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Biomedical subjects

K Conard

Publications and source records attributed to K Conard.

13 recordsLinked to original sources
PubMed2001

Experimental epiphysiodesis: magnetic resonance imaging evaluation with histopathologic correlation.

We performed an experimental epiphysiodesis on the tibia in 16 immature New Zealand white rabbits. The purpose was to study the process of trauma-induced growth plate closure. The animals were killed at weekly intervals over 8 weeks. We correlated the histological findings with serial magnetic resonance images. The undamaged, central part of the growth plate became histologically abnormal within 1 week. Mature bone bridge formation in the area of the epiphysiodesis was seen after 3 to 4 weeks. The study suggests that growth arrest starts before the bone bridge formation. Factors regulating cartilage growth may also play a role.

Animals↗
PubMed1999

Congenital disseminated malignant rhabdoid tumor: a distinct clinicopathologic entity demonstrating abnormalities of chromosome 22q11.

The clinical, pathologic, and immunohistochemical features of a widely disseminated tumor with rhabdoid phenotype are described in nine infants < or = 3 months of age. Five neonates had tumor evident at birth, two of which had placental metastases. The average survival following diagnosis was < 6 weeks. None of the infants had an apparent primary tumor in either the kidney or brain. In four cases, the dominant mass involved the head and neck region, and in two cases, the primary mass was paraspinal. The histologic features were those of a high-grade, round cell neoplasm with abundant cytoplasm and containing cells with cytoplasmic filamentous inclusions. Immunohistochemical studies revealed polyphenotypic antigen expression. Genetic information was available from eight of nine cases. Karyotype analysis revealed abnormalities of chromosome band 22q11-12 in three of six tumors. Fluorescence in situ hybridization studies or molecular studies demonstrated 22q11.2 deletions in all five cases with available frozen tissue, two of which had translocations involving 22q by karyotype analysis. The similar clinical and pathologic findings in these rapidly fatal tumors in infants and the demonstration of abnormalities of chromosome 22q11 in a majority of the cases supports their histogenetic and nosologic relationship to the family of malignant rhabdoid tumors that typically occur in young children in several anatomic sites, including kidney, soft tissues, liver, and brain. Like neuroblastoma and rhabdomyosarcoma, malignant rhabdoid tumor can appear as disseminated disease at birth or shortly thereafter.

Chromosomes, Human, Pair 22↗
PubMed1998

Bone scintigraphy in the detection of chronic recurrent multifocal osteomyelitis.

UNLABELLED: In this study, we describe the importance of the whole-body bone scan in diagnosing the multifocality of chronic recurrent multifocal osteomyelitis (CRMO) and in distinguishing it from unifocal acute hematogenous osteomyelitis. MATERIALS: The medical records and two-phase, whole-body bone scans of 14 patients (mean age 10.5 yr) with the diagnosis of CRMO, were retrospectively reviewed. The diagnosis of CRMO was based on bone biopsy in 9 patients and clinical course/laboratory findings in 5. Bone scans were evaluated for geographic and anatomic locations of their lesions. Correlative radiographs of areas of abnormal uptake were performed to assess the radiographic appearance of the lesions. RESULTS: The presentation of the disease was localized to one painful, tender and swollen periarticular site 86% of the time. The number of lesions detected by bone scan varied from 1-18 (mean 6). Most lesions were metaphyseal, proximal or distal tibial lesions. Purely sclerotic or mixed (sclerosis and lysis) lesions were found on radiographs. Bilateral lesions were seen in 64% of patients. Biopsies were negative for organisms in all patients and exhibited subacute or chronic histologic changes in most instances. Complications of chronic hyperemia included marked overgrowth (5), diffuse demineralization (1), angular deformity (1) and length discrepancy (1). CONCLUSION: The identification of the multifocal configuration of the disease process by two-phase (soft-tissue and delayed) whole-body bone scintigraphy results in appropriate diagnosis and therapy of CRMO. Additional sites for possible bone biopsy become apparent for exclusion of other diagnoses. Supportive (nonsteroidal, anti-inflammatory medication) instead of antimicrobial therapy can be initiated with significant cost savings.

Bone and Bones↗
PubMed1997

Mesenchymal chondrosarcoma of the cervical spine in a child.

Mesenchymal chondrosarcoma is a rare small-cell neoplasm of bone and soft tissue. After reviewing the literature, we believe that the patient in this report is the youngest in whom mesenchymal chondrosarcoma originating in a cervical vertebra has been diagnosed.

Cervical Vertebrae↗
PubMed1996

Hairy polyp of the oropharynx: case report and literature review.

Hairy polyp of the oronasopharynx is an uncommon developmental malformation that is most frequently seen as a pedunculated tumor in the neonate. Derived from the ectoderm and mesoderm, this benign tumor generally has been classified as dermoid. The clinical presentation is dependent on the polyp's size and location. A full-term girl was evaluated for an oral mass that was first noted at the time of birth. Evaluation showed a 5- x 2.5-cm soft, nontender, skin-covered mass that protruded from the oral cavity. During surgery, it was noted that the stalk was attached to the superior pole of the left tonsil. The histology of the mass was consistent with a hairy polyp. Knowledge of this type of malformation facilitates early intervention and avoids significant morbidity.

Dermoid Cyst↗
PubMed1993

Inflammatory arthropathies in children with chromosomal abnormalities.

There are few observations of inflammatory synovitis in association with specific chromosomal abnormalities in children or adults. We review the genetic and rheumatic disease literature and describe the clinical, radiologic and pathologic features of a 14-year-old boy with trisomy 5q, terminal 2p deletion, developmental delay, and a 5-year course of a polyarticular, symmetrical arthropathy similar to juvenile rheumatoid arthritis. He was treated with multiple nonsteroidal antiinflammatory drugs, intramuscular gold, and oral methotrexate, but developed iridocyclitis, joint space narrowing with erosions, and multiple flexion contractures; disease progression slowed after addition of chlorambucil. The frequency and manner of association of genetic disorders with inflammatory arthropathies is presently unknown. Additionally, children with 2 major disabilities often require aggressive medical intervention to maximize their potential for adult independence.

Adolescent↗
PubMed1992

Bone marrow transplantation for Niemann-Pick type IA disease.

Bone marrow transplantation has been undertaken with encouraging results as therapy for a wide variety of lysosomal storage diseases. We report a case of Niemann-Pick disease Type IA in which, despite the presence of only mild hypotonia with depressed reflexes, the clinical course of the disease appeared to be only slightly modified by this procedure, which was performed at the earliest practical opportunity. The patient was diagnosed early when asymptomatic, because of a family history of an affected sibling who died at 14 months. He received a bone marrow transplant from an HLA-identical, MLC non-reactive sibling donor, whose leukocyte sphingomyelinase activity was in the homozygote normal range. There was adequate engraftment as evidenced by persistently normal leukocyte sphingomyelinase activities, and there was no evidence of graft-versus-host disease. Visceral storage and neurological impairment were less rapidly progressive than in his untreated sibling but he eventually died at 30 months. Autopsy confirmed that this was essentially due to the effects of the underlying Niemann-Pick disease. We conclude that despite some success in other neurovisceral lysosomal storage disorders, bone marrow transplantation is not likely to be an adequate treatment for Niemann-Pick disease Type IA.

Bone Marrow Transplantation↗
PubMed1991

Chromosomal translocation t(1;13)(p36;q14) in a case of rhabdomyosarcoma.

Cytogenetic studies of a rhabdomyosarcoma of mixed embryonal and alveolar histology in an 11-month-old male revealed a single structural abnormality, t(1;13)(p36;q14). This abnormality may define a subset of patients with a variant of the t(2;13)(q35;q14) translocation frequently seen in alveolar rhabdomyosarcoma.

Chromosomes, Human, Pair 1↗
PubMed1988

Genetic disorders and major extracardiac anomalies associated with the hypoplastic left heart syndrome.

All pediatric autopsies of patients with hypoplastic left heart syndrome seen during an 11-year interval were reviewed to determine the frequency of underlying chromosomal and single-gene defects and idiopathic major extracardiac anomalies associated with this common, lethal congenital heart abnormality. Of 83 patients identified, nine had underlying chromosomal abnormalities, four had single-gene defects, ten had one or more major extracardiac anomalies without an identifiable chromosomal or mendelian disorder, and two were infants of insulin-dependent diabetic mothers. Overall, 23 patients (28%) had a genetic disorder and/or major extracardiac anomaly. The substantial prevalence of genetic causes of and major extracardiac anomalies associated with hypoplastic left heart syndrome underscores the need for a detailed genetic evaluation for all patients with hypoplastic left heart syndrome.

Abnormalities, Multiple↗