PubMed Health⌕ Search

Biomedical subjects

T W Bauer

Publications and source records attributed to T W Bauer.

At least 19 recordsLinked to original sources
PubMed1992

Ki-67-determined growth fraction versus standard staging and grading parameters in colorectal carcinoma. A multivariate analysis.

BACKGROUND: The antibody Ki-67 binds to nuclei in all cell cycle phases except GO and can be used to measure growth fraction. Because proliferative activity has been linked to prognosis in neoplasia, the authors analyzed 100 cases of colorectal carcinoma, each with 3 or more years of follow-up, using Ki-67 immunostaining. METHODS: The Ki-67-positive nuclear area and total nuclear area of carcinoma cells in 20 microscopic fields were measured by computed morphometry. A Ki-67 score (percent positive nuclear area x 100) was calculated. The following characteristics also were recorded for each case: patient age and sex, tumor site and size, modified Dukes' stage, spread beyond bowel wall, lymph node status, tumor grade, histologic type, extramural venous spread, tumor growth pattern, fibrosis, lymphocytic infiltration, and mitotic rate. RESULTS: Ki-67 scores ranged from 1 to 90 (mean, 34.6). Ki-67 scores were higher in Stage A disease (versus Stage B, C, and D disease) but were not associated with survival. Survival curves differed by stage, lymph node metastases, infiltrative growth pattern, lymphocytic infiltration, fibrosis, extramural venous spread, and tumor grade in a univariate analysis. The infiltrative growth pattern (P = 0.04) and lymphocytic infiltration (P = 0.003) were features associated independently with survival after adjusting for modified Dukes' stage. Furthermore, the lack of a significant lymphocytic infiltrate was associated with a death rate 3.4 times greater than that occurring in patients with Stage B disease with a significant infiltrate. CONCLUSIONS: The authors conclude that proliferative activity in colorectal carcinoma as measured by Ki-67 immunostaining was not associated with prognosis.

Cell Division↗
PubMed1992

Biological response to chopped-carbon-fiber-reinforced peek.

Polymer composites are being recognized as important implant materials for fracture fixation plates. The use of a composite material is dependent upon the mechanical properties of the material and its biocompatibility. The primary objective of this project was to evaluate 30% chopped-carbon-fiber-reinforced poly(etheretherketone) (CFRPEEK) as a potential material for use as a fracture fixation plate. A two-phase study was conducted. The first phase analyzed the short-term biocompatibility of CFRPEEK through rabbit muscle implant testing. CFRPEEK exhibited a nonspecific foreign body tissue reaction similar to the response observed with ultra-high-molecular-weight polyethylene (UHMWPE). In the second phase, four-hole CFRPEEK plates were implanted as internal fixation devices for transverse midshaft femoral osteotomies in beagles. The plates were effective in promoting fracture healing. A nonspecific foreign body reaction was observed to the plates and to particulate debris.

Animals↗
PubMed1992

Polyethylene debris-induced osteolysis and loosening in uncemented total hip arthroplasty. A cause of late failure.

Uncemented total hip arthroplasty has proven to be an acceptable alternative to cemented total hip arthroplasty with good short-term results. With the elimination of the use of polymethyl methacrylate for component fixation, failure at the bone-cement interface, with resultant osteolysis and progressive loosening, was thought to be preventable. Unfortunately the ultra-high-molecular-weight polyethylene acetabular insert can wear and produce particulate debris. This debris can stimulate an osteolytic reaction and lead to late aseptic loosening in a cementless total hip arthroplasty.

Acetabulum↗
PubMed1992

Tissue reactivity of anti-Leu19.

Monoclonal antibody anti-Leu19, is a marker of natural killer cells. Since reactivity between anti-Leu7, another natural killer cell marker, and small cell neuroendocrine carcinomas has been described, we evaluated the reactivity of anti-Leu19 in 92 neuroendocrine tumours. Frozen sections in each case were immunostained using the avidin-biotin-peroxidase complex method with monoclonal anti-Leu19. We found Leu19 expression in 93% of the cases. We also evaluated 149 other tumours, including adenocarcinomas, undifferentiated large cell carcinomas, lymphomas, melanomas and soft tissue tumours. We found Leu19 expression in 36% (by liberal interpretative criteria), or 29% (by conservative interpretative criteria) of these cases. Thus, while anti-Leu19 appears to be a sensitive marker for neuroendocrine tumours, a lack of specificity limits its practical application in diagnostic histopathology.

Antigens, CD↗
PubMed1992

Results of implant retrieval from postmortem specimens in patients with well-functioning, long-term total hip replacement.

The evaluation of postmortem specimens provides a unique opportunity to gain understanding of the interface between host and well-functioning prostheses unavailable from revision specimens that, by nature, are accompanied by the artifacts generated during their removal. The preliminary findings from the relatively limited number of specimens described in this collaborative study demonstrate the value of the effort and are presented to encourage surgeons to participate in this program and to make their patients aware of the value of the information they may provide.

Adult↗
PubMed1991

Juxta-articular osteoid osteoma.

Osteoid osteomas that arise at the end of a long bone, within the insertion of the joint capsule (juxta-articular, intra-articular), may cause misleading clinical, radiographic, and histologic findings, resulting in unnecessary diagnostic tests and a delay in definitive treatment. To clarify optimum diagnostic procedures, we reviewed 20 cases of juxta-articular osteoid osteomas and found a mean delay from presentation to correct diagnosis of 24 months. Plain radiographs were either negative or showed only secondary changes. A periosteal reaction and proliferative synovitis with chronic inflammation was common, which could be misinterpreted as rheumatoid arthritis. Optimum diagnostic procedures were a bone scan followed by plain tomograms and an excisional biopsy of the nidus.

Adolescent↗
PubMed1991

Hydroxyapatite-coated femoral stems. Histological analysis of components retrieved at autopsy.

Plasma-sprayed coating of hydroxyapatite are biocompatible and, because of their osteoconductive properties, may contribute to the early fixation of total joint prostheses. To evaluate this interface, we histologically analyzed five hydroxyapatite-coated femoral stems which, along with the surrounding bone, were retrieved from three humans at autopsy. The five femoral components had been in situ for a mean duration of twelve months (range, almost five to twenty-five months) and had been inserted for osteonecrosis (two), osteoarthrosis (two), and as an uncermented revision for failure of a cemented stem. The three patients had had a good or excellent clinical result and had died of causes unrelated to the joint arthroplasty. A coating of hydroxyapatite was identified on each stem. There was a variable amount of apposition of bone (32 to 78 per cent of available surface per section). The deposition of bone was most prominent on the surface of the prosthesis that was close to the endosteal surface of the bone, especially in areas that are predicted by Wolff's law (anterior and medial aspects of the implant, and at lateral-oblique corners). There were occasional foci of bone-remodeling around the implant, including osteoclast-mediated removal of the coating of hydroxyapatite along with adjacent bone. Occasional particles of ceramic were present within macrophages in the adjacent bone marrow. Other areas showed formation of new bone with a few areas of bone directly against the metal substrate. The over-all histological features suggest mechanically stable implants with bone-remodeling at the surface of the bone-implant interface.

Adult↗
PubMed1991

A new model to assess tibial fixation in knee arthroplasty. I. Histologic and roentgenographic results.

A model to assess tibial fixation in knee arthroplasty is described. Eighteen mongrel dogs were implanted with a right tibial hemiarthroplasty. Implantation was of a press-fit, smooth implant (eight dogs) or a titanium alloy beaded device (ten dogs). Animals were studied at six, 12, 18, and 24 weeks. Roentgenographic and histologic analysis was performed for all implants. All animals were ambulatory. Roentgenographically, smooth implants showed progressive radiolucencies with increasing trabecular sclerosis under the implants. These changes were less prominent under the porous implants. Histologically, fibrous interfaces were identified focally under all implants but were thicker under smooth devices. Eighteen- and 24-week specimens showed substantial ingrowth into the porous pegs but minimal ingrowth into the porous plateau. Concurrent histologic and biochemical evaluation in dogs demonstrates the possible fate of implants in knee arthroplasty in human beings. As has been observed, histologic analyses suggest that clinically satisfactory results do not constitute evidence of stabilization by bone ingrowth.

Animals↗
PubMed1991

A new model to assess tibial fixation. II. Concurrent histologic and biomechanical observations.

A tibial hemiarthroplasty model was designed to allow concurrent histologic and biomechanical analysis of the tibial implant-bone interface. In this study, micromotion was visually observed at the implant-bone interface of cemented and uncemented implants. Six dogs had staged bilateral implantation. Biomechanical analysis of three- and 12-month specimens was correlated with histologic analysis of the same specimen. Load transmission involved compression of trabecular bone and fibrous tissue at the interface. Failure of the interface occurred through cyclic fatigue and microfracture of trabeculae. Micromotion was seen at all interfaces, porous or smooth, cemented or uncemented. Displacement was greatest under an eccentrically loaded plateau. Micromotion at ingrown and cemented interfaces was because of trabecular compression. Uncemented smooth devices and uncemented porous devices with fibrous fixation of the plateau appeared unstable. The cemented implants and a single uncemented implant studied at 12 months showed no interface micromovement. The absence of micromovement in the uncemented implant was associated with subsidence and with ingrowth of 30% into the porous peg and porous plateau.

Animals↗
PubMed1991

Osteonecrosis of the femoral head. A prospective randomized treatment protocol.

Conservative treatment versus core decompression for cases of osteonecrosis (ON) of the femoral head was prospectively reviewed in 36 patients. A preoperative evaluation of the patients' history, physical examination, Harris Hip Score, roentgenograms, computed tomography, bone scan, magnetic resonance imaging, and measurement of the intraosseous pressure was used to grade the level of ON according to a rating system developed by Ficat. Hips were randomized to core decompression or conservative treatment groups. Fifty-five hips in 36 patients were randomized (29 surgical and 26 conservative). When success was gauged by Harris Hip Scores for Stage I hips, treatment was successful for seven of ten (70%) operatively treated hips and one of five (20%) non-operatively treated hips. Among Stage II hips, treatment was successful for five of seven (71%) decompressed hips and none of seven conservatively treated hips. Successful treatment was accomplished in eight of 11 hips (73%) and one of ten hips (10%) in decompression and conservative groups, respectively, for Stage III hips. Stages 0 and IV had groups too small for comparison. Less successful results were seen if roentgenographic criteria of success were used. Survival analysis showed more favorable results with surgical treatment. Core decompression produced better results than conservative treatment in the early stages of ON.

Adolescent↗
PubMed1990

Ki-67 and grading of malignant fibrous histiocytomas.

Although generally considered to be of high grade, malignant fibrous histiocytomas (MFH) show a range of histologic appearances and a diverse biologic behavior. More precise grading of this type of sarcoma is desirable. The rate of cell proliferation may reflect clinical behavior. A more sensitive measure of cell proliferation is the expression of the Ki-67 antigen. Frozen sections were prepared from 29 cases of MFH. Sections were immunohistochemically stained for Ki-67, and the results were quantitated by image analysis (CAS 100). The Spearman rank correlation test was used to compare the extent of the Ki-67 staining with the conventional histologic grade, nuclear grade, number of mitoses, extent of necrosis, and overall cellularity. There was a significant correlation between the extent of Ki-67 staining and the nuclear grade (cc = 0.56; P = 0.002) and overall histologic grade (correlation coefficient = 0.58; P = 0.001), but there was no significant, independent correlation between Ki-67 and prognosis.

Adult↗
PubMed1990

Hepatic giant cell carcinoma. An ultrastructural and immunohistochemical study.

Hepatocellular carcinoma with osteoclast-like giant cells (hepatic giant cell carcinoma [HGCC]) is a rare entity, with only three cases reported. The tumor is histologically similar to giant cell tumor (GCT) of bone, and the origin of the multinucleated giant cells and mononuclear stromal cells has not been determined. The purpose of this report is to present a case of this rare tumor and compare its ultrastructural and immunohistochemical features with those of a conventional GCT of bone. Histologically, the HGCC consists of sheets of osteoclast-like giant cells with a background of mononuclear cells. The giant cells lack the pleomorphism seen in hepatocellular carcinomas with anaplastic giant cells. At the light microscopic level, most of this tumor was nearly identical to a GCT of bone, but several microscopic fields (less than 5% of the tumor) had the histologic appearance of a "usual" hepatocellular carcinoma. The hepatic tumor was negative for HAM 56, epithelial cytokeratins, muramidase, and alpha-1-antitrypsin, with only focal positivity for chymotrypsin in mononuclear and giant cells. The GCT was strongly positive for alpha-1-antitrypsin and chymotrypsin in both the mononuclear and giant cells and showed focal, weak staining for AE1 and AE3 in the mononuclear stromal cells. Ultrastructurally, both mononuclear and giant cells of the HGCC showed features typical of hepatocellular carcinoma. Although the patient presented in this report died, the pattern of growth was different from most hepatocellular carcinomas. The overall histologic features of this tumor are distinctive and appear to justify separating this variant from other types of hepatocellular carcinoma.

Adult↗
PubMed1990

A prospective comparison of DNA quantitation by image and flow cytometry.

Advances in computer and video technology suggest that image analysis may be practical method of measuring DNA that also allows visual confirmation of cell type. The purpose of this study was to prospectively compare DNA quantitation from 92 solid tumors in which DNA indices had been measured by image analysis of touch preparations (CAS 100) and flow cytometry of cell suspensions (FACScan). For 81 cases, there was excellent correlation between the two methods. For nine cases, however, an aneuploid population, usually near tetraploid, was identified by image but not by flow cytometry. Three cases had aneuploid peaks by flow cytometry that were not identified by image. Although these methods show good correlation, rare populations may be missed by CAS, presumably because of sampling errors in the touch preparation. Aneuploid populations may also be missed by flow cytometry, either because of cell loss during processing or because visual identification by image can increase sensitivity.

Adenocarcinoma↗
PubMed1990

DNA quantitation by image cytometry of touch preparations from fresh and frozen tissue.

Using formalin-fixed, paraffin-embedded tissue for DNA quantitation has several disadvantages, including sacrifice of tissue and relatively poor resolution. DNA quantitation of touch preparations by image cytometry correlates well with flow cytometry, and analysis of touch preparations made from frozen tissue may offer an alternative method for retrospective studies. The authors compared the results of DNA quantitation of fresh and frozen tissue touch preparations in 59 solid tumors. For 54 cases there was excellent correlation. In three cases with multiple aneuploid peaks, the same populations were identified by each method, but different proportions of cells from each stemline were present in the fresh and frozen samples. In two cases there was a discrepancy between the DNA indices; the imprints showed different cell morphologic characteristics, suggesting different stemlines or areas of tumor differentiation. The authors conclude that DNA quantitation from touch preparations of frozen tissue by image cytometry provides a desirable alternative to sacrificing formalin-fixed tissue.

Cell Separation↗
PubMed1990

Nodular fasciitis presenting as an eyelid mass.

A case of nodular fasciitis occurring in the eyelid is presented. The clinical and pathologic features of this rare cause of an eyelid mass are discussed. Nodular fasciitis should be considered in the pathologic differential diagnosis of connective tissue tumors of the periorbital region. It is important not to confuse nodular fasciitis with fibrosarcoma, as simple excision is curative for this condition.

Child↗
PubMed1990

Making core decompression work.

Meaningful assessment of a treatment modality for osteonecrosis (ON) must take into account a number of factors: (1) an accurate diagnosis, (2) consistent staging of the disease process, (3) understanding of the variability of the disease, (4) consistent application of the treatment modality (or the surgical technique), and (5) a clear understanding of the goal of the treatment used. This article reviews the important steps of a diagnostic algorithm that has been used to accurately diagnose and stage the disease process of ON. A consistent surgical technique with clearly defined goals is also outlined. The results of two clinical studies that were based on these diagnostic and therapeutic philosophies and that assess the role of core decompression in the treatment of ON are reviewed. The first study compared core decompression to conservative management in a prospective randomized study of 55 hips. Decompression provided more predictable pain relief and changed the indications for further surgical intervention more consistently than did conservative management. The second study represents a preliminary review of a ten-year study of the decompression procedure; it showed that core decompression was particularly useful in Stage I and Stage II ON. Roentgenographic stabilization was most predictable for Stage I hips. Core decompression can be a safe, effective, and predictable procedure in the treatment of Stage I and Stage II ON.

Adult↗
PubMed1989

The rate of vascularization of coralline hydroxyapatite.

Coralline hydroxyapatite (CHAP) is a porous, biocompatible bone-graft substitute manufactured by the Replamineform process. The use of this material in the experimental and clinical settings for maxillofacial onlay grafting has been recently described. This study was designed to quantitate the rate of vascularization of coralline hydroxyapatite when used in an onlay application to membranous bone in an animal model. Sixteen onlay grafts of coralline hydroxyapatite (0.5 X 0.5 X 1.0 cm Interpore 200) were placed in a subperiosteal location on the nasal dorsum of 2- to 3-kg male New Zealand white rabbits. The grafts and nasal bones were harvested en bloc at 1, 2, 3 and 4 weeks after onlay. Prior to harvest, injectable silicone visualizing agent (Microfil*) was injected by means of carotid artery cutdown. The decalcified specimens were examined on a digitizing pad to count the number of vessels appearing in the blocks of hydroxyapatite. Counting was summed and integrated by an Apple IIe microcomputer. A significant difference (p less than 0.05) was noted in both the number of vessels and the fraction of implants infiltrated by vessels between 1 and 4 weeks. The usefulness of these previously undescribed data may be in their extrapolation to onlay grafts of coralline hydroxyapatite in maxillofacial reconstruction in humans.

Animals↗