Biomedical subjects

W A Zuelzer

Publications and source records attributed to W A Zuelzer.

11 recordsLinked to original sources

PubMed2001

pN collagen type III within tendon grafts used for anterior cruciate ligament reconstruction.

This study measured the amount of immature collagen type III present in tendon rafts obtained from anterior cruciate ligament (ACL) reconstructions. These values were compared with those obtained from control grafts typically used for reconstruction--Achilles, patellar, and fascia lata--and also to the normal ACL. Analyses were performed using a commercially available radioimmunoassay (RIA). The RIA made use of a rabbit polyclonal antibody specific to the amino terminus of procollagen type III. The specificity of the Ab was confirmed by a western blot. Fibril diameter of each of the above samples was measured by transmission electron microscopy (TEM). We thus were able to determine if there was a relationship between pN collagen III content and fibril diameter. The mean amount of pN collagen type III in the normal tendon control group was 0.8 +/- 0.3 ng/microg total protein (range 0.0-2.5 ng/microg). There was significantly greater pN collagen III (16 +/- 3.7 ng/microg total protein) in the grafts containing an average fibril diameter <55 nm than in the normal tendons or ACL (P < 0.05). Grafts with an average fibril diameter >55 nm had similar levels of pN collagen III (1.0 +/- 0.79 ng/microg) as the controls. There was also significantly less pN-collagen III within the functional grafts (5.3 +/- 1.9 ng/microg) as compared to failed grafts, (21.6 +/- 5.1 ng/microg, P < 0.05). These results indicate that incomplete processing of procollagen III may be responsible for some of the ultrastructural alterations seen in tendon grafts. Since ultrastructural organization is believed to influence mechanical properties of these tissues. pN collagen III levels may be a possible indicator of ligament or tendon weakness.

Achilles Tendon↗

PubMed1999

Differences in mRNA expression patterns between patellar tendons and anterior cruciate ligaments of immature pigs.

The patellar tendon is the most commonly used graft source in reconstruction of the anterior cruciate ligament. The performance of a patellar tendon graft in such a reconstruction is largely related to the structural and functional differences between patellar tendons and anterior cruciate ligaments. From a genetic point of view, the structural and functional differences are ultimately decided by the differential patterns of gene expression between the two tissues. In the present study, the genetic differences between normal patellar tendons and normal anterior cruciate ligaments were explored by screening a large number of mRNA species to detect the species unique to each tissue. Of the approximately 1,000 mRNAs screened, 20 differentially expressed mRNA species were detected. Eight were unique to patellar tendons, and 12 were unique to anterior cruciate ligaments. Of these 20 unique mRNA species, 12 did not match any of the known sequences in gene databases and were probably novel genes. Transcriptional control is a major step in the genetic pathway; therefore, the variations found between patellar tendons and anterior cruciate ligaments at this level of gene expression indicate that the differences between the two tissues are likely more extensive than previously thought. These differences probably influence the survival of patellar tendon autografts and should be explored further.

Animals↗

PubMed1997

Biochemical and molecular homogeneity in the patellar tendon of the immature pig.

Patellar tendon is widely used for reconstruction of the anterior cruciate ligament. However, few studies have investigated the tendon's homogeneity, a characteristic often assumed of it in experiments. In this study, the assumption that the patellar tendon is homogeneous was tested by dividing the central half of the tendon into six sections along its length and width and comparing commonly measured biochemical parameters and patterns of gene expression among these sections. No significant differences were found between the sections for any of the studied parameters: water content (p > 0.5), DNA content (p > 0.9), total collagen content (p > 0.8), amount of type I collagen (p > 0.7) or type-III collagen (p > 0.7), or expression of mRNA (p > 0.9). For all parameters, the minimum power value for statistical analyses was greater than 0.80. It was concluded that the central half of the tendon is homogeneous in terms of all of the measured parameters. The results provide important information for the many experiments that sample part of the patellar tendon to infer the characteristics of the whole tendon, e.g., biopsy studies.

Animals↗

PubMed1996

Magnetic resonance imaging in musculoskeletal assessment: a surgeon's perspective.

Magnetic resonance (MR) imaging is a significant advance in musculoskeletal noninvasive visualization, especially for the soft tissues including the menisci. The purpose of this article is to give the radiologist a surgeon's perspective on the role of this technology in clinical practice. For MR imaging to be cost effective, it must accurately define anatomy, and reveal changes that have an impact on patient care--i.e., be clinically relevant. For MR imaging to be accurate, optimum software, hardware, and an experienced radiologist are essential. However, even if an MR examination has high accuracy, the abnormal findings of this evaluation may not be related to the clinical problem that the patient presents with. This is supported by the demonstration that asymptomatic patients may have grade 3 meniscal tears, herniated discs, and rotator cuff changes. The MR examination may not change patient management even if it demonstrates pathologies such as a meniscal tear. The patient may tolerate the dysfunction and pain. The most cost-effective method of providing musculoskeletal care is still a careful history and competent physical examination.

Adolescent↗

PubMed1990

Traumatic pseudoaneurysm in a wrestler.

An 18-year-old man sought treatment for a pulsatile mass in the medial distal thigh four years after he had sustained blunt trauma during a wrestling match. Investigation, which included magnetic resonance imaging and arteriography, showed the mass to be a pseudoaneurysm, which should be considered in the differential diagnosis of masses resulting from direct, blunt trauma. At exploration, a pseudoaneurysmic thrombus in the superficial femoral artery was evacuated and the vessel was repaired with an interposition graft of reversed saphenous vein, followed by complete recovery of the patient.

Adolescent↗

PubMed1990

Core decompression for avascular necrosis of the femoral head: correlation between long-term results and preoperative MR staging.

A long-term radiographic follow-up study was conducted on 24 patients (34 hips) who underwent core decompression of the femoral head for avascular necrosis (AVN). The purpose of the study was to assess the potential correlation between the extent of AVN, as determined with preoperative magnetic resonance (MR) imaging, and development of collapse. The preoperative MR results were classified into four categories: group A, no AVN; group B, less than 25% involvement of the weight-bearing portion of the femoral head; group C, 25%-50% involvement; and group D, more than 50% involvement. Histologic evidence of AVN was found in all 34 hips. Collapse occurred in none of the hips in groups A and B (n = 12), in three of seven hips (43%) in group C, and in 13 of 15 hips (87%) in group D. It is concluded that MR estimation of the extent of femoral head involvement with AVN may help in predicting which femoral heads will collapse shortly after core decompression, so that this invasive procedure can be avoided in patients at risk.

Adult↗

PubMed1988

Femoral head avascular necrosis: MR imaging with clinical-pathologic and radionuclide correlation.

A retrospective evaluation of magnetic resonance (MR) imaging for the detection of avascular necrosis (AVN) of the femoral head was performed in 49 patients (85 hips) with clinical suspicion of AVN. Positive findings at bone biopsy or evidence on plain radiographs was considered proof of AVN. Absence of clinical symptoms and of radiographic findings for a minimum of 18 months after MR imaging was considered evidence of the absence of AVN. All patients were studied with plain radiography and technetium-99m methylene diphosphonate bone scintigraphy. Five hips had negative MR images, positive findings at bone marrow biopsy, positive bone pressure measurement (BMP), and positive bone scans. A comparison between MR images and bone scans showed MR imaging to be superior, with a sensitivity of 88.8% (vs. 77.5%) and a specificity of 100% (vs. 75%). BMP was the most sensitive (92%) but least specific test (57%).

Adolescent↗

PubMed1988

Arthroscopic training using pig knee joints.

Arthroscopy can be a difficult technique for the resident and staff physician to master. Various models have been constructed to allow the training arthroscopist time to perfect the technique. Aside from cadaver knees, there has been only one report of a successful in vivo training model. Sectioned pig knee joints for teaching and practicing arthroscopy satisfy many of the points suggested by others: they are cost effective, easy to use, mount and store, provide a realistic approach, and have comparable structural anatomy to the human knee.

Animals↗

PubMed1987

Avascular necrosis of the femoral head: early MRI detection and radiological correlation.

Magnetic Resonance Imaging (MRI) and conventional radiographs were compared in 49 hips with Avascular Necrosis (AVN). MRI detected AVN in 25% of the hips during the preradiological stage of the disease. Both MRI and conventional radiographs accurately detected AVN in the remaining 75% of hips. Correlation between the patterns observed with the two techniques reflected the underlying histopathologic events. The reactive interface between infarcted bone and viable bone could be identified on MRI as a low signal intensity (SI) band. On conventional radiographs the reactive interface appeared as a sclerotic band. The adjacent hyperemic zone was seen on MRI as a high SI band and as a lucent zone on the plain films. Variations of this pattern occurred as related to the extend and duration of AVN and to the individual's ability to mount a healing response. Minor degrees of collapse of the femoral head were better identified with plain radiographs but MRI demonstrated small areas of hyperintensity probably corresponding to early subchondral fractures.

Femur Head Necrosis↗

PubMed1986

Ankle: surface coil MR imaging at 1.5 T.

High-field surface coil magnetic resonance (MR) images were obtained of 12 ankles: two from healthy volunteers, seven from patients, and three from fresh cadavers. The cadaver ankles were sectioned in the coronal, sagittal, and axial planes for direct comparison with the MR images. Plain film confirmation of pathologic conditions was obtained in all patients, and five underwent arthroscopy or surgery, or both. MR imaging provided excellent delineation of ligaments and cartilaginous structures in all cases.

Ankle↗

PubMed1979

The dorsal ganglion with anomalous muscles.

Either an anomalous extensor indicis proprius muscle or an extensor digitorum brevis manus may coexist with a dorsal wrist ganglion. To assure relief of symptoms, treatment must include division of the fourth dorsal extensor compartment in the case of the former muscle, and excision in the case of the latter.

Adult↗