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Biomedical subjects

R W Hendrix

Publications and source records attributed to R W Hendrix.

At least 91 records · Page 5Linked to original sources
PubMed1982

Radiologic evaluation of surgical cervical spine fusion.

Preoperative, intraoperative, and postoperative radiologic evaluation of surgical cervical spine fusion plays an integral part in the management of cervical spine injuries. The radiographic anatomy of the basic types of anterior, posterior, and combined fusions and the indications for their performance are discussed. A retrospective review of 210 consecutive cervical spine fusions showed a 21.1% radiographic complication rate for anterior fusions and only 3.9% for posterior fusions. The high complication rate of anterior fusions is related to the performance of anterior fusion in the presence of unrecognized posterior instability. Radiographically identified complications must be correlated with the clinical neurologic examination in each case since the spectrum of radiographic complications may be compatible with a clinically satisfactory result.

Adolescent↗
PubMed1981

Radiology of pressure sores.

Pressure sores occur frequently in patients with spinal cord injuries and require radiographic evaluation for adequate management. Plain radiography, computed tomography, direct magnification radiography, sinography, and ultrasonography were used to evaluate 218 pressures sores. The role of each of these modalities in the management of patients with pressure sores is defined, and recommendations for their use are made.

False Positive Reactions↗
PubMed1981

Arthrographic and radiologic evaluation of prosthetic joints.

Arthrography is indicated for the evaluation of a prosthetic joint for suspected infection, possible loosening based on clinical or plain radiographic findings, or unexplained pain following the insertion of a prosthesis. Interpretative difficulties most frequently occur when the acetabular component of the hip is evaluated. Also, the femoral component of a total knee arthroplasty is not optimally evaluated with arthrography. The decision to revise a loose prosthetic component is based on a clinical judgment. Arthrographic findings may facilitate this decision, but the decision does not depend solely on the arthrographic results. Rather, they must be evaluated in conjunction with other clinical and radiographic findings to eliminate false positive studies, thereby avoiding unnecessary surgery. In the presence of an equivocal arthrogram, radionuclide bone imaging shows promise as an adjunct for evaluating possible failure of a prosthetic component. It is also useful for evaluating the suspected failure of the femoral component of a knee prosthesis.

Bone Cements↗
PubMed1979

The radiologic significance of the left pulmonary ligament. Experience with 26 patients.

Pathologic processes confined to or by the left pulmonary ligament present a confusing radiographic appearance. Such processes may simulate pleural scarring, parenchymal scarring, or even left lower lobe collapse. Radiologic awareness of this structure is limited because in the normal state, it is not visualized on either posteroanterior or lateral chest x-ray films. The absence of secondary signs of left lower lobe collapse, together with a process which may extend above the level of the left hilum, is valuable in confirming that such a triangular density seen behind the left cardiac border is disease in or confined by the pulmonary ligament, rather than left lower lobe collapse.

Adult↗
PubMed1978

Role of the host in virus assembly: cloning of the Escherichia coli groE gene and identification of its protein product.

Correct assembly of the heads of bacteriophages lambda and T4 requires the function of the groE gene of the Escherichia coli host. We have isolated a transducing derivative of lambda, called lambda gt-Ec.groE, that carries a functional copy of the groE gene. Unlike wild-type lambda, this phage is able to form plaques on hosts with a mutant groE gene. We have isolated an amber mutation in the groE gene carried by the phage, and this has made it possible to identify the groE product as a protein of molecular weight 65,000. In the phage, the groE gene is under the control of an early phage promoter.

Bacterial Proteins↗
PubMed1978

Symmetry mismatch and DNA packaging in large bacteriophages.

A model is presented for the mechanism of packaging double-stranded DNA into phage heads. The model is based on, and rationalizes, the mismatch in symmetry between the heads and tails of large bacteriophages. DNA movement is postulated to be mediated by a rotating protein structure at the tail-proximal vertex of the head.

Bacteriophages↗
PubMed1977

Scintigraphic evaluation of lymphoma: a comparative study of 67Ga-citrate and 111In-Bleomycin.

Sequential whole-body scans with both 67Ga-citrate and 111In-bleomycin were performed for 14 patients undergoing staging for Hodgkin's disease or other lymphomas. A comparison or these scans gave a sensitivity in detecting the pathologically-proved tumor sites of 84% for 67Ga-citrate and only 56% for 111In-bleomycin. In 12 patients, the gallium scan demonstrated the lesions more clearly; in the others, the uptake of the two radionuclides was equal. In no case was a clinically diagnosed or histologically proved lesion identified by 111In-bleomycin that was not also demonstrated by 67Ga-citrate. 111In-bleomycin does not complement the 67Ga-citrate scan in the scintigraphic evaluation of lymphomas.

Adolescent↗
PubMed1976

Efficacy of emergency radionuclide perfusion lung studies.

Over a one-year period, 206 patients with suspected pulmonary embolism received gamma camera perfusion lung images on an emergency 24 hr. basis. Clinical diagnosis listed pulmonary embolism in 37 of 39 patients whose images showed a high probability of it, in 28 of 69 whose images were abnormal but rated uncertain probability, and 5 of 98 with normal images. Retrospective clinical evaluation indicated 89 of the emergency images to be considered important, 95 contributory, and 22 not helpful in clinical management. As a result of the images, 80 patients were placed on heparin therapy of 198 considered for it, and 22 of 29 patients referred for hospital admission were placed on an outpatient basis. Delay in obtaining lung images creates the possibility of diagnostic uncertainty in interpreting the image.

Adolescent↗
PubMed1975

The matrix of the optic vesicle-presumptive lens interface during induction of the lens in the chicken embryo.

The cell coats of the presumptive lens cells and the extracellular interface between the lens rudiment and optic vesicle were investigated in the chicken embryo throughout the period during which lens induction is presumed to take place. Histochemical methods showed that the cell coats contained both glycoproteins and glycosaminoglycans. Autoradiography after [3H]glucosamine injection indicated incorporation of the precursor with subsequent localization primarily at the cell surface. No obvious changes in the properties of the coat were noted with the progression of early lens morphogenesis. The extracellular matrix at the interface between ectoderm and optic vesicle also contained glycoprotein and glycosaminoglycan. There was a heavy concentration of [3H]glucosamine-containing macromolecules in the area. Electron microscopy revealed that the interface consisted of the basement membrane systems of lens and optic vesicle, fused with their external fibrillar layers. In contrast to the findings on cell coats the density of the interfacial matrix increases appreciably during the lens induction period. Evidence suggests that the cells of the two ocular epithelia are themselves the source of the matrix materials. It is proposed that the macromolecules excreted by the epithelial cells into the interface interact at different concentrations to form aggregates of various structure by a process of self-assembly. This may be reflected in the different ultrastructure of the layers of the interfacial matrix. Quantitative changes in the density of the matrix, leading to increased adhesion between lens rudiment and optic vesicle, may restrict the lateral spreading of the lens cells and so fix the basal area of the lens rudiment. This, together with continued cell replication, may produce the cell crowding, placode formation and invagination characteristic of lens morphogenesis.

Amylases↗