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Biomedical subjects

D Resnick

Publications and source records attributed to D Resnick.

At least 37 records · Page 2Linked to original sources
PubMed1992

Knee effusion: normal distribution of fluid.

Although visualization of articular fluid on MR images of the knee is common, no specific MR criteria that enable assessment of the quantity of the effusion have been established. We performed MR of three cadaveric knee specimens after the instillation of increasingly large volumes of fluid and studied the distribution of the fluid. When 4 ml of fluid was injected, the anteroposterior diameter of the suprapatellar recess was 4 mm on midline sagittal MR images and 10.0-12.5 mm on lateral sagittal MR images, corresponding to the usual routine radiographic criteria for a knee effusion.

Humans↗
PubMed1992

Injuries of the superior portion of the glenoid labrum involving the insertion of the biceps tendon: MR imaging findings in nine cases.

The goal of this investigation was to describe the MR appearance of traumatic fraying or detachment of the superior portion of the glenoid labrum including the insertion of the tendon of the long head of the biceps. This condition is caused either by an acute injury or by repeated overhead motion during participation in sports. In nine patients with such a lesion, the arthroscopic report and MR images were available for review. These patients were 22-64 years old (mean, 38). In four patients only fraying was noted during arthroscopy, in four patients the superior part of the labrum was detached together with the insertion of the biceps tendon, and in one case there was a bucket-handle tear of the superior portion of the labrum. The MR images were retrospectively evaluated by three osteoradiologists in conference. Signal changes within the labrum and detachment of the labrum were noted, and the findings were compared with the results of arthroscopy. MR imaging did not allow recognition of simple fraying. In two of the five cases with arthroscopic findings of detachment of the superior labrum from the glenoid rim, differentiation between complete and partial labral detachments was not possible even with MR arthrography. However, in these cases the patient's age and history led to the correct diagnosis. We conclude that early traumatic abnormalities of the superior portion of the labrum cannot be detected with MR imaging. Complete detachment, however, can be demonstrated if the patient's age and history are taken into consideration.

Adult↗
PubMed1991

The type I and type II bovine scavenger receptors expressed in Chinese hamster ovary cells are trimeric proteins with collagenous triple helical domains comprising noncovalently associated monomers and Cys83-disulfide-linked dimers.

Scavenger receptors have been implicated in the development of atherosclerosis and other macrophage-associated functions. The structures and processing of type I and type II bovine macrophage scavenger receptors were examined using polyclonal anti-receptor antibodies. Pulse/chase metabolic labeling experiments showed that both types of scavenger receptors expressed in Chinese hamster ovary (CHO) cells behaved as typical cell surface membrane glycoproteins. They were synthesized as endoglycosidase H-sensitive precursors which were converted to endoglycosidase H-resistant mature forms expressed on the cell surface. The reduced precursor and mature forms were doublets on sodium dodecyl sulfate-gel electrophoresis, primarily because of heterogeneous N-glycosylation. The approximate molecular sizes were: type I precursor, 65/63 kDa; type I mature, 82/76 kDa; type II precursor, 57/53 kDa; and type II mature, 72/65 kDa. During post-translational processing, the cysteine-rich C terminus (SRCR domain) of some of the type I receptors was proteolytically removed to form a relatively stable, approximately 69-kDa degradation product. Type II receptors differ from type I receptors in that they do not have SRCR domains and an analogous proteolytic cleavage was not observed. Several experiments provided strong evidence that the Gly-X-Y-repeat domains in the scavenger receptors oligomerize into collagenous triple helices. For example, alpha,alpha'-dipyridyl, an inhibitor of the collagen-modifying enzymes prolyl and lysyl hydroxylases, interfered with both the kinetics and nature of post-translational receptor processing, and both precursor and mature forms of the receptors in intact cells could be cross-linked with difluorodinitrobenzene into reduction-resistant trimers. In intact cells, precursor receptor trimers (type I, 198 kDa; type II, 176 kDa) were assembled in the endoplasmic reticulum by the noncovalent association of monomers and Cys83-disulfide-linked dimers (type I, 129 kDa; type II, 119 kDa). When cells were lysed in the absence of the sulfhydryl trapping agent iodoacetamide, oxidation of the side chain of Cys17 in the cytoplasmic domain leads to the artifactual formation of reduction-sensitive covalently linked trimers. The approximate masses of the mature dimer and trimer forms were 162 and 237 kDa for type I receptors and 147 and 219 kDa for type II receptors. Cys83-disulfide-linked dimer formation was not required for function because mutant receptors (Cys83----Gly83) assembled into trimers of noncovalently associated monomers and exhibited normal receptor activity. Treatment of cells with difluorodinitrobenzene cross-linked some of the receptors into complexes larger than trimers, raising the possibility that the trimers may assemble into higher order oligomers.

2,2'-Dipyridyl↗
PubMed1991

Metastases to bone affected by Paget's disease. A report of three cases.

Three cases of metastatic disease in bone affected by Paget's disease are presented. The literature has been reviewed and a total of 26 similar cases found. The occurrence is rare compared to the frequency of sarcomatous transformation in Paget's disease, and low considering the frequency with which metastatic disease and Paget's disease each affect the elderly. This suggests that pagetic bone may resist the implantation of metastatic tumour cells.

Adenocarcinoma↗
PubMed1991

Human immunodeficiency virus infection in cases presenting to the Philadelphia Medical Examiner's Office.

Serum samples were available from 492 of 1,058 cadavers seen at the Philadelphia Medical Examiner's Office between August 4 and December 15, 1989. These sera were tested for the presence of antibodies to human immunodeficiency virus (HIV) by enzyme-linked immunosorbent assay (ELISA) and Western blot. The overall prevalence of HIV in the autopsy population was 2.24%. The following populations showed increased prevalence as compared to the total sampled population: blacks (3.60%, p less than 0.01), males (2.51%, n.s.), and homicide victims (3.74%, n.s.). Seroprevalence data from this study are compared with those from earlier studies of other related populations, with regard to overall prevalence and risk factor analysis.

Black or African American↗
PubMed1991

Knee hyaline cartilage evaluated with MR imaging: a cadaveric study involving multiple imaging sequences and intraarticular injection of gadolinium and saline solution.

Magnetic resonance (MR) imaging of cadaveric knees was performed to determine optimal sequences for visualization of hyaline cartilage. Six fresh-frozen cadaveric knees were imaged with a 1.5-T imager by means of standard and hybrid fat suppression (HFS) spin-echo techniques, with and without intraarticular injection of saline solution and gadopentetate dimeglumine. The knees then were sectioned at 4-mm intervals. Both the real and the imaged cartilage thicknesses were measured. Areas of cartilage thinning and focal defects seen in the cadaveric sections were most accurately matched, in both the presence and the absence of intraarticular saline solution simulating joint fluid, by images obtained with the T1-weighted HFS sequences. Accurate imaging of hyaline cartilage thickness with differentiation of cartilage from fluid was possible routinely. Standard and HFS spin-echo images obtained after intraarticular injection of gadopentetate dimeglumine depicted cartilage less accurately than HFS sequences either with or without saline injection. MR imaging with T1-weighted HFS sequences provided superior visualization of cartilage, enabling accurate measurements of cartilage thickness and differentiation of cartilage from saline solution simulating joint fluid.

Cartilage, Articular↗
PubMed1991

Medial dislocation of the biceps brachii tendon: appearance at MR imaging.

Abnormalities of the long tendon of the biceps brachii muscle commonly accompany other lesions about the shoulder, especially rotator cuff rupture, and are a frequent cause of a painful shoulder. The spectrum of abnormalities associated with medial displacement of the biceps tendon seen at magnetic resonance (MR) imaging was reviewed in six patients. MR imaging was performed on a 1.5-T system with use of a dedicated surface coil. The findings at MR imaging were correlated with those at surgery. Two types of medial displacement of the biceps tendon were identified. More frequently observed was a defect in the subscapularis apparatus that allowed intraarticular entrapment of the biceps tendon. Less commonly observed was incomplete dislocation, with the biceps tendon lying between a partially disrupted subscapularis tendon. MR imaging enabled accurate identification of medial dislocation of the biceps tendon and entrapment of the tendon within the glenohumeral joint. MR imaging also demonstrated the associated disruption of the subscapularis tendon that must be present to allow the biceps tendon access to the joint space.

Aged↗
PubMed1991

Triangular fibrocartilage and intercarpal ligaments of the wrist: MR imaging. Cadaveric study with gross pathologic and histologic correlation.

To provide further understanding of the magnetic resonance (MR) signal intensities in the triangular fibrocartilage (TFC) and interosseous ligaments of the wrist, the authors performed MR imaging with gross pathologic and histologic analysis in 10 cadaveric wrists. Spin-echo T1- and T2-weighted coronal images were obtained, and 3-mm coronal sections of the specimens were then made that correlated precisely with the MR images. Normal portions of the TFC showed asymmetrical bow tie-like low signal intensity, except near the radial and ulnar attachments. Degeneration of the TFC, present in all cases, was more severe on the proximal surface and was characterized by high signal intensity on T1-weighted images and less high signal intensity on T2-weighted images. These findings differed from those in TFC perforation, which showed high signal intensity on T2-weighted images. Similar signal intensity characteristics could allow differentiation of degeneration and perforation of the scapholunate and lunotriquetral ligaments. These findings suggest that in vivo MR imaging may accurately delineate degeneration and perforation of the TFC and intercarpal ligaments.

Cadaver↗
PubMed1991

Alterations in the supraspinatus tendon at MR imaging: correlation with histopathologic findings in cadavers.

To determine the histopathologic correlates of alterations in the rotator cuff at magnetic resonance (MR) imaging, 13 cadaveric shoulders (in subjects aged 26-83 years at the time of death) underwent MR imaging in the coronal oblique plane at 1.5 T with proton-density- and T2-weighted spin-echo sequences. Areas corresponding to sites of MR imaging alterations were then examined histologically. Increased signal intensity on proton-density-weighted images (without further increased signal intensity on T2-weighted images) and an indistinct margin at the articular side of the supraspinatus tendon corresponded to eosinophilic, fibrillar, and mucoid degeneration and scarring. Areas of increased signal intensity on T2-weighted images were associated with severe degeneration and disruption of the supraspinatus tendon. Although other authors have suggested that certain MR findings are indicative of tendinitis, the histologic data in this study were not those of active inflammation but rather tendon degeneration.

Adult↗
PubMed1991

Cervical paraspinal calcification in collagen vascular diseases.

Although soft-tissue calcification is common in collagen vascular disease, paraspinal calcification in the cervical spine has not been described before. We studied five women with large, lobulated, predominantly homogeneous calcific masses centered on synovial articulations in the neck. Changes consisting of either osteolysis or erosions were evident. All patients had radiculopathy, focal pain, or stiffness. In two patients, the presence of hydroxyapatite crystals was confirmed on biopsy. Symptomatic cervical paraspinal calcifications in patients with collagen vascular disease cause large soft-tissue masses that mimic tumoral calcinosis.

Aged↗
PubMed1991

Magnetic resonance imaging of the wrist.

Until recently magnetic resonance imaging of the musculoskeletal system tended to be confined to the larger joints, such as the knee and shoulder. Advances in magnetic resonance technology, especially in the area of improved software and development of surface coils, have made feasible the imaging of smaller joints, such as the wrist. This article reviews the potential applications of magnetic resonance in evaluating disorders of the wrist.

Carpal Tunnel Syndrome↗
PubMed1990

A guanosine diphosphatase enriched in Golgi vesicles of Saccharomyces cerevisiae. Purification and characterization.

We have recently described a luminal guanosine diphosphatase activity in Golgi-like vesicles of Saccharomyces cerevisiae (Abeijon, C., Orlean, P., Robbins, P. W., and Hirschberg, C. B. (1989) Proc. Natl. Acad. Sci. U. S. A. 86, 6935-6939). The presumed in vivo role of this enzyme is to convert GDP into GMP. GDP is a reaction product following outer-chain mannosylation of luminal proteins and a known inhibitor of mannosyltransferases. It is hypothesized that GMP then returns to the cytosol. We have purified this enzyme to apparent homogeneity. Following solubilization from a membrane pellet using a buffer containing Triton X-100, the enzyme was purified on a concanavalin A-Sepharose column followed by Mono Q fast protein liquid chromatography (FPLC) and Superose-12 FPLC columns. After treatment with endoglycosidase H, the deglycosylated active enzyme was applied to a second Mono Q FPLC column and a phenyl-Superose FPLC column. The final enzyme activity was enriched 6500-fold over that of the Triton X-100 extract. The apparant molecular mass of the deglycosylated enzyme is 47 kDa. The purified enzyme is highly specific for guanosine diphosphate, requires Ca2+ for maximal activity, and has a broad pH optimum between 7.4 and 8.2. The apparent Km for GDP is 0.1 mM; the Vmax is 4.9 mmol/min/mg of protein. An enzyme activity with similar substrate specificity has also been detected in membranes of Schizosaccharomyces pombe.

Chromatography, Affinity↗
PubMed1990

Magnetic resonance appearance of sacral insufficiency fractures.

Insufficiency fractures of the sacrum are a commonly recognized form of stress fracture typically occurring in elderly patients. As such patients usually present with low back pain, MR imaging is often performed initially as a means of evaluation. We present 5 patients with sacral insufficiency fractures imaged with MR. Metastatic disease was a leading clinical suspicion as all patients were elderly and three had known primary neoplasms. T1-weighted sequences demonstrated bands of decreased signal intensity, usually paralleling the sacral aspect of the sacroiliac joints and occasionally occurring as a horizontal band across the sacral body. Four of five patients underwent further evaluation with computed tomography (CT) or nuclear bone scanning, which confirmed the diagnosis of sacral insufficiency fracture. We conclude that MRI is sensitive but not specific in detecting sacral insufficiency fractures. As MR imaging is rapidly becoming the method of choice for evaluating back pain, it is important to consider this diagnosis in elderly persons.

Aged↗
PubMed1990

The effect of intra-articular gadolinium-DTPA on synovial membrane and cartilage.

This investigation evaluated the potential effect of gadolinium (Gd)-DTPA-dimeglumine on synovial membrane and joint cartilage, using macroscopic, microscopic, and x-ray fluorescent spectroscopic techniques. Thirteen New Zealand white rabbits (26 knees) were used in this study, ten receiving 500 micromolar injections of Gd-DTPA-dimeglumine in their right knees; the remainder of the knees served as controls. One injected knee had minimal joint effusion and one had mild hyperemia. Microscopically four knees exhibited mild focal hyperplasia of the synovium, another three minimal focal mononuclear cell infiltration. X-ray fluorescent spectroscopy demonstrated no evidence of Gd-DTPA-dimeglumine in the synovium or articular cartilage. Neither macroscopic nor microscopic evaluation detected any Gd-DTPA-dimeglumine related effects. Gd-DTPA-dimeglumine was found to be safe for intra-articular injection in this animal model.

Animals↗
PubMed1990

Detection of thoracolumbar vertebral body destruction with lateral spine radiography. Part I: Investigation in cadavers.

Despite few and inconclusive studies, radiography is generally believed to be insensitive for detection of osteolytic lesions of the spine. A more detailed investigation was undertaken to study the detectability of laboratory-produced osteolytic lesions in cadaveric thoracolumbar vertebral bodies using conventional lateral radiographs. The radiographs were presented to four radiologists in two sessions over a two month period. In the first session, the films were arranged in a composite of five vertebral bodies, T11 to L3 all from the same spine, in which one contained a lesion and the other four were normal. In the second session, each vertebral body film was presented individually. Area (Az) under the receiver-operating characteristic (ROC) curve was used to measure the performances of readers. Observer detection was similar in the two formats with Az ranging from 0.67 +/- 0.05 to 0.79 +/- 0.04 for the composite film arrangement and 0.57 +/- 0.08 to 0.85 +/- 0.10 for the films of individual vertebral bodies. Lesions were grouped into three relative size categories: 18% to 25%, 26% to 40%, and 41% to 60% of transverse vertebral body diameter. The mean increase in ROC area between the small and large lesions was 0.29 (P less than 0.04) for the composite films and 0.16 (P less than 0.05) for the individual films. In the composite study, all readers showed significant (P less than 0.05) increases in lesion detection in spines reflecting large increases (P less than 0.01) in bone mineral content.(ABSTRACT TRUNCATED AT 250 WORDS)

Cadaver↗