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Biomedical subjects

V T Tolo

Publications and source records attributed to V T Tolo.

At least 19 recordsLinked to original sources
PubMed1994

Congenital dislocation of the hip.

Neonatal hip dysplasia remains a difficult condition to diagnose and treat. Early periodic infant hip examination is the primary screening tool, but subtle hip instabilities can go undetected until fixed dislocations are discovered when the child begins to walk. Early nonoperative intervention in the neonatal period is usually effective using a Pavlik-type harness. For infants in whom this disorder is discovered after walking age, surgery is often needed to successfully reduce the hip. Radiographic evaluation of neonatal hip dysplasia is often difficult, but the evolving use of ultrasound, computed tomography, and magnetic resonance imaging is making this easier. The role of ultrasound as a primary screening device in the United States remains to be defined.

Hip Dislocation, Congenital↗
PubMed1994

Immunocytochemical detection of cyclin A and cyclin D in formalin-fixed, paraffin-embedded tissues: novel, pertinent markers of cell proliferation.

Cyclin proteins in association with cyclin-dependent protein kinase subunits represent a new class of potentially oncogenic serine/threonine protein kinases that function to execute critical cell cycle transitions in all eukaryotic cells. Characterized by dramatic fluctuations in abundance, which occur in accordance with the periodicity of the cell cycle, the expression patterns of specific cyclins provide a unique and relevant indicator of cellular activation and cell cycle progression. In this study, we introduce a series of monospecific antibodies that are selective for human cyclin A and cyclin D, respectively, and we assess the feasibility of utilizing these reagents for immunocytochemical analyses. Conditions were optimized for detecting cyclin A and cyclin D in formalin-fixed, paraffin-embedded sections of the postnatal human palatine tonsil, in which normal cell proliferation is well characterized. Subsequent studies demonstrated the performance of these antibodies in the examination of pediatric bone tumors, in which decalcification methods are additionally performed. In both cases, the proliferative status of individual cells was monitored with an exceedingly high degree of resolution. Taken together with the available biochemical data, the results of these studies reveal a novel means of characterizing the proliferative status of normal as well as neoplastic tissues. The demonstrated utility of these immunochemical reagents will potentially facilitate retrospective studies aimed at examining cell proliferation in a wide variety of archival histopathologic specimens.

Antibodies↗
PubMed1994

Molecular cloning of the human CAK1 gene encoding a cyclin-dependent kinase-activating kinase.

Cyclin-dependent, proline-directed protein kinases normally function to execute critical cell cycle transitions; abnormal expression and/or viral subversion of the positive (cyclins) and negative (Pic1) regulatory subunits may contribute to neoplastic transformation and tumorigenesis. In addition to the binding of regulatory subunits, the enzymatic activities of the cyclin-dependent kinases, Cdc2 and Cdk2, are tightly regulated by site-specific protein phosphorylation events. Recent studies have identified a critical phosphorylation site (Thr-161) located within kinase Subdomain VIII that is necessary for Cdc2 activation, and enzymatic activities capable of carrying out this heterologous phosphorylation event have been detected in both Xenopus oocytes and human somatic cells. In this report, we characterize by molecular cloning a human homologue of the Xenopus Cdk-activating kinase (Cak, encoded by MO15); the novel human gene is designated (HS)CAK1. While only 75% identity is observed at the nucleotide level, the deduced amino acid sequence encoded by (HS)CAK1 is approximately 87% identical to that of the Xenopus MO15 gene in corresponding regions. The catalytic domain of (HS)Cak1, defined by conserved kinase Subdomains I through XI, exhibits considerable homology with (HS)Cdc2, suggesting that this kinase cascade involves closely related enzymes. Immunological studies with anti-Cak antibodies confirm the presence of specific immunoreactivity in highly purified preparations of the human Cdc2-activating kinase. The molecular characterization of (HS)CAK1 should facilitate studies of its physiological regulation, as well as its potential utility as a target for therapeutic intervention in the treatment of proliferative disorders.

Amino Acid Sequence↗
PubMed1993

Outcome of Wisconsin instrumentation in idiopathic scoliosis. Minimum 5-year follow-up.

Wisconsin segmental spinal instrumentation was developed by Drummond et al to provide rigid fixation for correction of spinal deformities without the risk of neurologic injury associated with the passage of sublaminar wires. Up to this point, there have been no outcome studies with follow-up of longer than 2 years. Thirty-five patients with adolescent idiopathic scoliosis treated by the Wisconsin procedure between 1984 and 1987 were reviewed by radiographs, physical examination, and an outcome scale. Minimum length of follow-up was 5 years with an average of 6.3 years. Curves were corrected from a mean of 59 degrees preoperatively to 32 degrees postoperatively (46%), and 36 degrees at final follow-up (39%). Wisconsin segmental spinal instrumentation did not increase thoracic kyphosis. There was evidence of slight lumbar flattening in long fusions. According to the criteria described, 92% had a successful outcome. Complications of the procedure included two wound infections (one superficial, one deep), one rod displacement, and two wire breakages. No pseudarthroses or neurologic complications were identified in this series. Wisconsin segmental spinal instrumentation safely achieves the objectives of partial correction, arthrodesis, and early return to function. The technique may still have a role, particularly in the thoracic region, in selective thoracic fusion of King type II curves, rigid curves, and double thoracic curves.

Adolescent↗
PubMed1991

Avoiding paraplegia during anterior spinal surgery. The role of somatosensory evoked potential monitoring with temporary occlusion of segmental spinal arteries.

Three patients paraplegic following anterior spinal fusion for congenital kyphoscoliosis were noted to have complete somatosensory evoked potential signal loss shortly after segmental arterial ligations at the apex of their respective kyphosis. This has prompted us to use temporary segmental arterial occlusion with somatosensory evoked potential monitoring prior to ligation during anterior spinal fusion. As a result, we have noted seven additional cases, out of a total of 44 cases monitored in this fashion, in which complete loss of somatosensory evoked potential signals, reversible by release of vascular clips, has occurred. For each of these additional cases the critical segmental arteries were identified and were not ligated, usually resulting in some modifications in the planned surgical procedure, and the patients remained neurologically intact. We recommend temporary segmental arterial occlusion with somatosensory evoked potential monitoring during thoracolumbar anterior spinal fusion to potentially avert ischemic neurologic injury. Based on published data and the experience described herein, this technique should be especially important in anterior spinal fusion for congenital kyphoscoliosis.

Adolescent↗
PubMed1990

The incidence and natural history of scoliosis in Rett syndrome.

A survey on spinal deformity was conducted by means of a questionnaire mailed to the 350 American families who are members of the International Rett Syndrome Association. 258 questionnaires were completed and further information (medical records and radiographs) was received from treating physicians. Scoliosis was present in 119 patients, whose clinical details are discussed. Patients with Rett syndrome frequently develop progressive scoliotic deformities. The incidence increases with age, occurring most commonly during the second decade. Bracing to control curve progression has been largely unsuccessful for adolescent patients.

Adolescent↗
PubMed1990

Spinal deformity in short-stature syndromes.

Although almost any spinal deformity can occur in any skeletal dysplasia, there are specific spinal problems in each disorder that require periodic assessment and a particular awareness. Atlantoaxial instability frequently accompanies spondyloepiphyseal dysplasia congenita and Morquio's syndrome. Severe progressive kyphoscoliosis is found in diastrophic dysplasia. Although scoliosis can be found in many of these syndromes to some degree, it is very rare in achondroplasia. The most common deformity found in skeletal dysplasias as a whole seems to be kyphosis: cervical kyphosis in diastrophic dysplasia and thoracolumbar kyphosis in achondroplasia, pseudoachondroplasia, and many of the short-stature syndromes of metabolic etiology. Spinal stenosis is extremely common in achondroplasia, both at the lumbar and cervical areas. It is important to establish the correct diagnosis early so that the orthopaedist is able to focus on the areas at highest risk of developing spinal problems, and proceed with efficacious and timely treatment.

Dwarfism↗
PubMed1990

External fixation in multiply injured children.

External fixation treatment for selected fractures can be as readily applied to children as to adults, although only a small percentage of pediatric fractures require this method. The best situations for the use of external fixation in children are in cases of multiple organ system injuries and in fractures associated with skin loss or large wounds. In these situations, while the child's other problems are being treated, external fixation provides excellent temporary stabilization to facilitate fracture management.

Adolescent↗
PubMed1990

Vascularized fibular grafts in the treatment of congenital pseudarthrosis of the tibia.

Free vascularized fibular bone grafts were used in nineteen children, seen consecutively, who had congenital pseudarthrosis of the tibia. The average age was 5.1 years (range, 1.4 to 11.4 years). Sixteen of the patients had been treated with electrical stimulation for at least one year, and the tibia had not united. All but four patients had had at least one previous operative procedure. At an average follow-up of 6.3 years (range, 2.0 to 11.0 years), eighteen (95 per cent) of the nineteen pseudarthroses had healed. The leg-length discrepancy averaged 1.6 centimeters (range, 0 to 4.0 centimeters), but ten tibiae had residual or progressive valgus or anteroposterior malalignment despite bracing. There was minimum morbidity at the donor site.

Bone Transplantation↗
PubMed1989

Surgical treatment of adolescent idiopathic scoliosis.

The surgical management of idiopathic scoliosis requires knowledge in several areas. In selecting patients for surgical care, it is necessary to know the natural history for the type of curve present during the teenage years, as well as what can be expected of this type of curve during adult life. Preoperative evaluation must include screening for other than idiopathic causes before surgery is advised. Appropriate attention to preoperative radiographs, possible autologous blood utilization, and planning for spinal cord monitoring are essential. Finally, the ability to use a variety of techniques in spinal deformity surgery is needed, as is the knowledge of which technique or instrumentation is best in each situation. Although the surgical care of spinal deformity has become more complex and requires attention in several areas, the advances in surgical care and in spinal instrumentation allow us to correct spinal deformity more safely and predictably in a more three-dimensional manner than was feasible even a decade ago.

Adolescent↗
PubMed1988

Pseudopseudohypoparathyroidism with spinal cord compression.

We describe a patient with pseudopseudohypoparathyroidism who had an osseous tubercle on the anterolateral margin of the foramen magnum causing compression of the spinal cord. This patient had no evidence for any endocrinopathies and had no other spinal canal anomalies. We suggest that the morphologic phenotype found in patients with pseudopseudohypoparathyroidism, also known as Albright's hereditary osteodystrophy, has an associated risk for spinal cord compression due to congenital vertebral anomalies. The poor recovery of neurologic function following spinal decompression mandates prompt recognition and therapy of this condition in patients with Albright's hereditary osteodystrophy.

Adolescent↗
PubMed1988

Nutritional deficiencies after staged anterior and posterior spinal reconstructive surgery.

The nutritional status was analyzed in 37 patients being treated with staged anterior and posterior spinal reconstructive procedures. Using stringent criteria for nutritional and immunologic incompetency, 31 patients (84%) became malnourished during hospitalization. Although the serum albumin on admission had been normal for all patients, it became significantly depressed in 77% following anterior and posterior spinal procedures. In a similar fashion, the total lymphocyte count became significantly depressed in 92%. The postoperative complications were clearly more extensive in patients who were malnourished and immune-deficient using these criteria--15 patients with urinary tract infections, four patients with bacterial sepsis, four patients with wound infections, and four patients with pneumonia (vs. one with a wound infection in the adequately nourished group). The length of hospitalization following the second operative procedure was significantly longer in the malnourished group: 16.2 days versus 12.4 days (p less than 0.05). The main purpose of this study is to create awareness of the ongoing nutritional demands placed on patients treated by two-stage spinal reconstruction surgical procedures. More aggressive nutritional intervention can reduce postoperative complications and length of hospital stay and improve the speed of functional recovery.

Adolescent↗
PubMed1986

A comparison of nitroglycerin and nitroprusside for inducing hypotension in children: a double-blind study.

Intravenous nitroglycerin (NTG) and sodium nitroprusside (SNP) were compared as hypotensive agents in anesthetized children and adolescents. The drugs were studied in a prospective, randomized, double-blind fashion in 14 patients anesthetized with nitrous oxide: oxygen, morphine, and thiopental. NTG in doses as high as 40 micrograms X kg-1 X min-1 was ineffective at decreasing mean arterial pressure (MAP) below 55 mmHg or causing a decrease in MAP greater than one-third of baseline values. SNP was uniformly successful at inducing hypotension in all patients, including those patients in whom NTG failed. The dose of SNP required to induce hypotension was 6-8 micrograms X kg-1 X min-1. Both NTG and SNP decreased systemic vascular resistance, although SNP did so to a much greater degree than NTG (64% vs. 29%; P less than 0.01). Only SNP increased cardiac index significantly (2.27 +/- 0.35 to 4.44 +/- 1.36; P less than 0.003). Both drugs reflexly increased heart rate, necessitating the use of intravenous propranolol (range from 1 to 3 mg) in all patients. Both drugs produced small decreases in arterial oxygen tension and increases in the average alveolar-arterial oxygen tension gradient (SNP, 44 +/- 13 vs. NTG, 41 +/- 6). SNP use was associated with a slight metabolic acidosis (pH = 7.38 +/- 0.01; base excess [BE] = -6 +/- 1). Neither drug produced any other untoward reaction. SNP appears to be the agent of choice for the reliable and sustained induction of deliberate hypotension in children and adolescents.

Adolescent↗