Search PubMed⌕ Search

Biomedical subjects

H S Schwartz

Publications and source records attributed to H S Schwartz.

At least 19 recordsLinked to original sources
PubMed2002

Clonality studies in giant cell tumor of bone.

Genetic studies including chromosome analysis, telomere reduction and telomere activity, DNA microsatellites and loss of heterozygosity (LOH) studies have been performed on giant cell tumor (GCT) of bone however whether this primary skeletal neoplasm represents a monoclonal or polyclonal proliferation is unknown. Utilizing a new assay to study the polymorphic human androgen receptor locus (HUMARA), the ratio of maternal inactive X-chromosome to the paternal inactive X (Lyon hypothesis) is determined via a methylation--specific polymerase chain reaction (PCR) technique to detect X-chromosome polymorphisms. Characterization of the genetic tumorigenesis of this unpredictable neoplasm may lend insight into its biological behavior and offer improvements in therapeutic intervention, as new information emerges regarding osteoclastic bone resorption. Seventeen female patients with giant cell tumor of bone had their DNA harvested and their X-chromosome inactivation pattern and polymorphisms determined and compared to control. A polyclonal proliferation pattern was identified in all informative samples studied.

Adult↗
PubMed2000

Microsatellite instability in sacral chordoma.

BACKGROUND AND OBJECTIVES: Microsatellite instability (MIN) is an indirect marker of globally defective DNA mismatch repair in the neoplastic cells of cancer patients. Chordomas are rare, primary skeletal malignancies for which few characteristic molecular genetic markers have been identified. Is MIN demonstratable in chordoma? METHODS: We evaluated sacral chordomas from 12 patients with sacral chordomas for the presence of MIN at 9 different genetic loci from chromosomes 1p, 5q, 7q, 9p, 11p, 12p, 13q, 17p, and 18q. Cells were scraped from glass slides so that tumor and control DNA could be isolated and then amplified by polymerase chain reaction (PCR). Heterozygosity indices were >/= 0.70. RESULTS: Six patients (50%) demonstrated MIN for at least 1 locus, and 2 patients demonstrated loss of heterozygosity (LOH) for at least 1 locus. Only 1 individual's chordoma manifested microsatellite instability (MIN) and loss of heterozygosity (LOH). Another patient manifested no MIN but LOH at 9p and 18q. Interestingly, this individual had the most aggressive clinical cancer course, presenting with lymph node metastasis and succumbing to widespread metastatic disease. CONCLUSIONS: Chordomas can be added to the list of malignancies demonstrating MIN. LOH may prove to portend a worse prognosis than MIN when more tumors are examined.

Adult↗
PubMed2000

Growth factor modulation of distraction osteogenesis in a segmental defect model.

A model was established in 39 dogs to investigate the growth factor modulation of regenerate bone in distraction osteogenesis. A segment of the diaphysis of the radius was resected unilaterally. An osteotomy was made proximal to the segmental defect to create a transport segment. A monolateral external fixator was applied. After a latency period, the segment was transported across the defect. One week after the transport assembly contacted the distal pin clamp, an ipsilateral osteotomy of the proximal ulna was performed. In 20 dogs, transforming growth factor-beta was injected into the regenerate bone halfway through the transport period. Four dogs were sacrificed before docking, when the regenerate bone was still immature. In specimens harvested halfway through the transport period, evidence was found of intramembranous ossification during distraction. In specimens harvested after the transport assembly contacted the distal pin clamp, evidence was found that the mature regenerate formed by endochondral ossification. Therefore, a combined mechanism of ossification is proposed for this segmental defect model that includes mechanical stimulus for bone differentiation. The one-time administration of transforming growth factor-beta retarded the formation of a stable, united regenerate. It is concluded that transforming growth factor-beta caused an effect opposite to that which was desired.

Animals↗
PubMed1999

Publication rates of abstracts presented at the 1993 annual Academy meeting.

What percent of abstracts presented at the American Academy of Orthopaedic Surgeons annual meeting are submitted, survive peer review, and eventually are published? The answer to this fundamental question is important because many national meeting attendees use the unscrutinized information that is presented to alter their surgical practices. At the 1993 American Academy of Orthopaedic Surgeons meeting, 573 abstracts were presented. After a 5-year period, 44% of abstracts presented were published as papers in a peer reviewed journal. The results suggest that for various reasons, the majority of presented material at the Academy meeting has not been authenticated scientifically to be as accurate as papers that survive the rigors of peer review.

Abstracting and Indexing↗
PubMed1999

Marjolin ulcers: secondary carcinomas in chronic wounds.

Marjolin ulcers are malignant tumors arising in chronic wounds. Strictly defined, they include carcinomas that transform from the chronic open wounds of pressure sores or burn scars. They behave aggressively and have a propensity for local recurrence and lymph node metastases. A retrospective study was done at a single institution identifying six individuals who had chronic wound ulcers that underwent malignant transformation into a carcinoma. Sinus tract degeneration in osteomyelitis was not included. The average latency time between ulcer formation and documentation of a malignancy was 30 years. All wounds were about the pelvis or flank. Major oncologic surgical procedures were done in an attempt to eradicate the cancer. High-grade tumors had positive lymph node metastases, portending a grave prognosis. All four individuals with nodal metastases eventually died of systemic disease. Early recognition and proper staging offers the best chance for cure.

Aged↗
PubMed1998

Microsatellite instability in malignant melanoma.

Defective mismatch repair has been detected in human colorectal and endometrial carcinomas which exhibit microsatellite instability (MIN). The purpose of this study was to search for MIN in melanoma. Paraffin-embedded neoplastic and non-neoplastic control cells were obtained from 20 untreated individuals with cutaneous malignant melanoma. Breslow thickness ranged from 0.2-7.4 mm (mean 1.4). Cells were carefully scraped from glass slides so that tumor and control DNA could be isolated and then amplified by polymerase chain reaction (PCR) at seven separate microsatellites localized to specific chromosome regions: 1p22 (D1S187), 5q11.2-13.3 (D5S107), 6q21-23.3 (D6S357), 9p21 (IFNA), 11p15.2 (D11S861), 17p13.1 (D17S786), and 18q11 (D18S34). Heterozygosity indices were > or = 0.70. Loci from these chromosome regions were chosen because of cytogenetic abnormalities reported in melanoma (1p, 6q, 9p), location of common oncogenes (11p-HRAS, 17p-TP53), or use in other MIN studies (5q, 18q). Five individuals (25%) demonstrated MIN. There was no correlation with tissue thickness. One individual demonstrated MIN at two loci and one individual demonstrated loss of heterozygosity. The results indicate that MIN occurs in melanoma, albeit less frequently than reported in carcinomas.

Adult↗
PubMed1998

Microsatellite instability in sarcomas.

BACKGROUND: Microsatellite instability (MIN) has been studied in a variety of carcinomas and gynecologic sarcomas, but never in musculoskeletal sarcomas. METHODS: We evaluated 16 skeletal and soft tissue sarcomas at nine genetic loci from chromosomal regions 1q, 5q, 7q, 12p, 13q, 17p, 19q, and two at 11p--all potential regions of interest regarding musculoskeletal sarcomas. RESULTS: MIN was identified at one or more loci in seven of the cancers studied (44%). Three tumors had more than one locus with MIN and one tumor, a high-grade osteogenic sarcoma, had five of nine loci positive for MIN. CONCLUSION: These results indicate that musculoskeletal sarcomas show instability in areas inside and outside the loci of known oncogenes. Areas of mismatch repair, as heralded by MIN, may contribute to the vast heterogeneity of these neoplasms.

Adolescent↗
PubMed1998

An analysis of concordance among hospital databases and physician records.

BACKGROUND: Hospital databases contain vital demographic patient information, which is increasingly being used as a basis to dictate care. It is hypothesized that the validity of data administratively generated from such sources is suboptimal, especially for rare subspecialties. The authors examined three databases to determine their concordance in an academic orthopaedic oncology subspecialty practice. METHODS: A 2-year retrospective review was performed on three databases searching for seven fundamental variables: additions/deletions; identification number; birthdate; procedure date; admit/discharge date; procedure code; and diagnostic code. Two university-maintained hospital databases (medical records and physician billing) were compared to the surgeon's personal handwritten daily log, which served as the "gold standard." RESULTS: All seven variables were in agreement with the physician's log in only 60% of the medical records and 61% of the physician billing patient entries (n = 564). On more detailed statistical analysis using chi(2), cross tabulations, and the K statistic for interobserver agreement, it was determined that poor concordance exists among the databases. CONCLUSION: Surgeons delivering quartenary care should maintain his or her own database because the hospital's information often differs on one or more important variables. Further investigation into the accuracy of hospital databases regarding commonly practiced medical disciplines appears warranted.

Academic Medical Centers↗
PubMed1998

Clear cell sarcoma or malignant melanoma of soft parts: molecular analysis of microsatellite instability with clinical correlation.

Malignant melanoma of soft parts, also termed clear cell sarcoma (CCS), is a rare malignancy of neural crest origin which is different from cutaneous malignant melanoma. Although a translocation involving chromosomes 12 and 22 is characteristic of clear cell sarcoma and not malignant melanoma, there are a paucity of methods to differentiate the two. Therefore, a study of microsatellite instability (MIN) was undertaken to determine if mechanisms of DNA mismatch repair can differentiate these malignancies. MIN has been described in a variety of malignancies including 25% of malignant melanomas. Paraffin-embedded neoplastic and non-neoplastic cells were obtained from 11 individuals (five males; six females; age range from seven to 60 years) with CCS. Isolated DNA was PCR amplified at 17 separate microsatellite loci using radioactive-labeled primers. Tumor tissue was compared to normal tissue for each analysis. No MIN was detected. Loss of heterozygosity was detected in only one patient at a single locus (IFNA). The lack of MIN in clear cell sarcoma further defines the distinction between this tumor and malignant melanoma. Clinically, local recurrence and metastasis were indicators of poor outcome. The size of the tumor was not a significant prognostic indicator. Local recurrence, satellitosis, or nodal metastasis was not proven to be uniformly fatal. Utilization of chemotherapy and/or radiation demonstrated no obvious survival advantage. The histologic parameters of mitotic rate and the presence of necrosis were not prognostic. Limb-preserving surgical procedures were as effective as amputation for local disease control. The actuarial survival rate was calculated to be 48% at five years.

Adolescent↗
PubMed1998

Update on giant cell tumor of bone.

Giant cell tumor of bone is a benign, primary skeletal neoplasm with an unpredictable pattern of biological aggressiveness. Molecular biological research has increased our understanding of these tumors. This article reviews recent advances in the study of this interesting bone tumor.

Bone Neoplasms↗
PubMed1997

Recognizable magnetic resonance imaging characteristics of intramuscular myxoma.

Extremity intramuscular myxoma is an uncommon, deep, benign soft-tissue neoplasm. It is characterized clinically by slow growth and minimal symptoms. Resection achieving wide surgical margins is curative. This article presents the imaging characteristics of five extremity intramuscular myxomas. Images of this benign neoplasm, especially magnetic resonance imaging, are characteristic enough for preoperative recognition. This knowledge can facilitate treatment by avoiding biopsy, permitting primary myectomy, and assisting the pathologist in diagnosing a neoplasm that frequently has overlapping histologic characteristics with other soft-tissue tumors.

Adult↗
PubMed1996

Analysis of variables affecting wound healing after musculoskeletal sarcoma resections.

Adjuvant treatment modalities, nutritional parameters, and allogenic blood transfusions are investigated as possible contributing variables which may adversely affect wound healing after tumor resections for musculoskeletal sarcomas. Statistical analysis determined that preoperative chemotherapy, depressed preoperative hematocrit, and allogenic blood transfusions (probably immunosuppression mediated) were the only significant factors affecting wound healing outcome. Suggestions to improve postoperative infection rates are discussed.

Analysis of Variance↗
PubMed1996

Chromosome telomere integrity of human solid neoplasms.

Eukaryotic chromosomes contain specialized structures at the termini called telomeres. This region of DNA is required for replication and stability of the chromosome. Telomere reduction can contribute to genetic instability and has been described in certain malignancies (e.g., colon, leukemia, giant cell tumor of bone). To determine whether telomere reduction is a generalized phenomenon in malignancies, the telomere integrity of genomic DNA isolated from tumor cells was determined from 39 individuals with 15 different malignancies categorized as musculoskeletal, epithelial, cranial, or other, and peripheral blood leukocytes from the same patient, when possible, or age-matched controls. Significant telomere reduction occurred randomly across histopathologic groups including giant cell tumor of bone, glioblastoma, colon cancer, and Wilms' tumor while telomere elongation occurred in chordoma. The other remaining 10 malignancies do not show significant differences in telomere lengths compared with controls.

Adolescent↗
PubMed1996

Lack of microsatellite instability in giant cell tumor of bone.

Microsatellite instability was searched for at six different loci on chromosome arms 5q, 18q, 15q, 17p, 19q, and 11p in 22 patients (12 men and 10 women; average age of 31.8 years, range of 20-55 years) with giant cell tumor of bone (GCT). These loci were chosen because of their use in microsatellite instability studies in other tumors such as colorectal cancer (e.g., 5q, 18q, 17p) or because of the presence of chromosomal abnormalities such as telomeric associations commonly occurring at 19q and 11p termini (thus the reason for including the 19q and 11p termini microsatellites in our study of GCT). No microsatellite instability or loss of heterozygosity were detected when comparing normal and tumor cells from any of the GCT patients. Unlike several other tumors, our study indicates that microsatellite instability does not appear to play a role in the tumorigenesis of GCT although other abnormal cytogenetic, biochemical, and molecular genetics data do exist for this musculoskeletal tumor.

Adult↗
PubMed1996

Heterogeneous survival rates for isolated skeletal metastases from melanoma.

In this study, the authors examine the survivorship of individuals who constitute the small subset of patients with Stage IV melanoma who present with their first and only detectable metastasis to the skeleton. One thousand two hundred six patients were identified with primary melanoma at the authors' institution since 1962. There were 14 patients with isolated (solitary) skeletal metastases. Survival was calculated by Kaplan-Meier technique. The survival rate for any individual with an isolated metastasis to the axial skeleton was 0. Three of 8 patients with melanoma metastases to the appendicular skeleton are alive at 18, 25, and 52 months after Stage IV detection. A statistically significant prolonged latency period (initial diagnosis to Stage IV) in the appendicular group compared with the axial group contributed to their significant survival rate advantage. The melanoma literature strongly supports the complete resection of soft tissue metastatic foci. These data support this concept and extend it to include isolated skeletal metastases. The mechanisms by which axial and appendicular skeletal metastases occur are significantly different. This difference manifests itself as a survival advantage for the appendicular group and warrants an aggressive surgical approach for these individuals.

Adult↗
PubMed1996

Operative treatment of fractures of the tibial plafond. A randomized, prospective study.

We performed a randomized, prospective study to compare the results of two methods for the operative fixation of fractures of the tibial plafond. Surgeons were assigned to a group on the basis of the operation that they preferred (randomized-surgeon design). In the first group, which consisted of eighteen patients, open reduction and internal fixation of both the tibia and the fibula was performed through two separate incisions. An additional patient, who had an intact fibula, had fixation of the tibia only through an anteromedial incision. The second group consisted of twenty patients who were managed with external fixation with or without limited internal fixation (a fibular plate or tibial interfragmentary screws). Ten (26 per cent) of the thirty-nine fractures were open, and seventeen (44 per cent) were type III according to the classification of Rüedi and Allgöwer. There were fifteen operative complications in seven patients who had been managed with open reduction and internal fixation and four complications in four patients who had been managed with external fixation. All but four of the complications were infection or dehiscence of the wound that had developed within four months after the initial operation. The complications after open reduction and internal fixation tended to be more severe, and amputation was eventually done in three patients in this group. At a minimum of two years postoperatively (average, thirty-nine months; range, twenty-five to fifty-one months), the average clinical score was lower for the patients who had had a type-II or III fracture, regardless of the type of treatment. With the numbers available, no significant difference was found between the average clinical scores for the two groups. All of the patients, in both groups, who had had a type-II or III fracture had some degree of osteoarthrosis on plain radiographs at the time of the latest follow-up. With the numbers available, there was no significant difference between the two groups with regard to the osteoarthrotic changes. We concluded that external fixation is a satisfactory method of treatment for fractures of the tibial plafond and is associated with fewer complications than internal fixation.

Adult↗