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R B McGhee

Publications and source records attributed to R B McGhee.

At least 19 recordsLinked to original sources
PubMed1996

Disseminated neuroblastoma in the nude rat. A xenograft model of human malignancy.

BACKGROUND: The overall survival of children with neuroblastoma remains less than 30% due to disease dissemination at the time of diagnosis. An animal model of neuroblastoma, with characteristics similar to those observed clinically in children, would be beneficial to investigations into the diverse biology of this tumor. The purpose of this study was (1) to develop a model of disseminated neuroblastoma in the nude rat by intracardiac injection of neuroblastoma cells derived from cell lines with different N-myc copy numbers; (2) to investigate the effect of age on tumor growth and dissemination; and (3) to assess progression of disease radiologically and correlate with autopsy findings. METHODS: Nude rats (n = 38), 5-13 weeks of age, underwent intracardiac injection of the human neuroblastoma cell lines IMR-32 with amplified N-myc oncogene and SKNSH with 1 N-myc copy. The animals were observed for at least six weeks for the development of tumor. Twelve rodents injected with IMR-32 cells underwent imaging studies including magnetic resonance imaging (MRI), skeletal radiographs, and indium-111(IN-111)-diethylenetriamine penta-acetic acid-D-Phe1-octreotide scintigraphy. Autopsies with standardized microscopic examinations were performed on all animals. RESULTS: Most of the nude rats (95%) developed neuroblastoma following intracardiac injection of neoplastic cells. Disseminated tumor was evident in 66% of animals. Anatomic sites of neuroblastoma growth were similar to those observed clinically in children, including adrenal glands, paraspinal ganglia, bone, bone marrow, and skin, but no tumor was identified in the liver. Disseminated disease occurred in more animals injected with IMR-32 (78% of animals) than with SKNSH cells (34% of animals) (P < 0.05). Tumor spread appeared to be age dependent; only rodents 5-8 weeks old at the time of injection developed disseminated disease when compared with animals 9 weeks of age or older (P < 0.0001). Radioreceptor scintigraphy demonstrated only pericardial tumor; MRI identified pericardial, adrenal gland, and subcutaneous neoplasms; only skeletal radiographs detected neuroblastoma in cortical bone. CONCLUSIONS: (1) Following intracardiac injection of human neuroblastoma cell lines into nude rats, a xenograft model of disseminated disease develops that closely parallels the malignant process in children. (2) Tumor dissemination is associated with the cell line that demonstrates N-myc amplification and with young age of the recipient at the time of injection. (3) Tumor growth and dissemination may be assessed radiologically. (4) This model of human malignancy may offer an opportunity to investigate the pathophysiologic mechanisms underlying tumor development and dissemination in advanced stage neuroblastoma.

Age Factors↗
PubMed1992

Magnetic resonance imaging correlates of neuropsychological impairment in multiple sclerosis.

The authors examined whether specific neuropsychological abnormalities in multiple sclerosis (MS) are associated with focal lesion areas detected by MRI. Lesion area, regardless of distribution, correlated with performance on the vast majority of neuropsychological procedures. No significant difference appeared between groups with normal/mild and moderate overall cognitive impairment on any of the MRI measures. However, patients with severe cognitive impairment had greater lesion area, regardless of location, and had significant atrophy of the corpus callosum compared with the other two groups. These results suggest that severe atrophy of the corpus callosum reflects global disease and provides a relatively focal morphological marker of severe cognitive impairment in MS.

Adult↗
PubMed1991

Cyclosporine-associated seizures in bone marrow transplant recipients given busulfan and cyclophosphamide preparative therapy.

Five of 182 recipients of allogeneic bone marrow transplants performed between 2/84 and 6/90 developed seizures while receiving cyclosporine and methylprednisolone to prevent acute graft-versus-host disease. All received a radiation-free regimen of busulfan and cyclophosphamide as preparative therapy. Two patients received HLA-mismatched allografts; and three patients received marrow from HLA-identical sibling donors. Two patients had received extensive intrathecal therapy prior to transplantation. All patients were receiving standard prophylactic doses of CsA and MP at the time of onset (median 31 days posttransplantation) of seizures. Three patients had mild-to-moderate hypertension and varying degrees of morphologic evidence of microangiopathic hemolytic anemia. None had unusually low magnesium levels. Cyclosporine levels were not in the toxic range. Cranial magnetic resonance imaging and computed tomography (CT) showed bilateral abnormalities primarily in the posterior temporal, occipital, and parietal lobes. These abnormalities were shown to be transient on sequential MRI exams in two patients. Seizures as well as radiologic abnormalities resolved on stopping CsA and did not recur in 2 patients who subsequently received CsA in lower doses. These findings confirm and expand previous observations of CsA-associated seizures and demonstrate that they occur in allogeneic bone marrow transplant recipients following a radiation-free preparative regimen of busulfan and cyclophosphamide.

Adolescent↗
PubMed1991

Cerebellorubral degeneration after resection of cerebellar dentate nucleus neoplasms: evaluation with MR imaging.

The authors describe the magnetic resonance (MR) findings in seven patients who developed severe cerebellar symptoms and atrophy of the contralateral red nucleus following removal of unilateral neoplasms in the deep nuclei of the cerebellum. For most patients, pre- and postoperative spin-echo MR images were obtained with long repetition times (TRs) at 1.5 T. The long TR images obtained before surgery demonstrated unilateral masses involving the dentate nucleus. Long TR images obtained after surgical resection of the dentate nucleus showed increased signal intensity in all of seven contralateral red nuclei, three of seven ipsilateral superior cerebellar peduncles, and two of seven contralateral inferior olivary nuclei. Three other patients who underwent surgery for cerebellar neoplasms without resection of the dentate nuclei showed no postoperative brain stem changes on MR images. The authors speculate that the changes in the contralateral red nuclei are due to cerebellorubral degeneration (since well-described neural tracts interconnect the dentate nucleus and the contralateral red nucleus). Injury of the dentate nucleus may result in degeneration of distant neural connections.

Adolescent↗
PubMed1990

Improving diagnostic accuracy of cervical metastases with computed tomography and magnetic resonance imaging.

Elective neck dissection in patients with head and neck cancer continues to be controversial. The management of these patients would be greatly facilitated by improvements in predicting cervical metastases. Recent investigations have suggested that computed tomography and magnetic resonance imaging are more sensitive in detecting cervical metastases than physical examination. The Department of Otolaryngology at the Ohio State University Hospitals, Columbus, undertook a prospective study to compare the preoperative sensitivities of physical examination, computed tomography, and magnetic resonance imaging with pathologic findings in 27 patients undergoing neck dissections for head and neck cancer. The results indicate that computed tomography and magnetic resonance imaging were more sensitive (84% and 92%, respectively) than physical examination (75%), although the results did not achieve statistical significance. The sensitivity of combined computed tomography and magnetic resonance imaging was 90%.

Head and Neck Neoplasms↗
PubMed1990

Ligaments of the lateral aspect of the ankle and sinus tarsi: an MR imaging study.

The normal anatomy of the lateral ankle and subtalar ligaments seen at magnetic resonance (MR) imaging was studied in four cadaver ankles. Sixteen ankles of 11 healthy volunteers were imaged with four different MR imaging protocols to optimize technique. The anterior talofibular ligament was identified in 100% of the ankles of the volunteers in the axial plane, the calcaneofibular ligament in 81% of the ankles in the coronal plane, the cervical ligament in 69% of the ankles in the coronal plane and in 88% of the ankles in the sagittal plane, and the talocalcaneal ligament in 56% of the ankles in the coronal plane and in 62% of the ankles in the sagittal plane. It is concluded that thin-section (1-3-mm) MR imaging techniques, especially the one in which data are acquired with three-dimensional Fourier transform, are best for visualization of the ligaments. These techniques may play a role in the evaluation of patients with chronic ankle pain and instability.

Adult↗
PubMed1988

Experimental infections of the musculoskeletal system: evaluation with MR imaging and Tc-99m MDP and Ga-67 scintigraphy.

Acute osteomyelitis, soft-tissue infection, or both were experimentally produced in 38 New Zealand white rabbits, and three-phase technetium-99m methylene diphosphonate, gallium-67, and magnetic resonance (MR) images were obtained 7 or 14 days after infection. There was no significant difference between radionuclide studies and MR images in the detection of osteomyelitis, but MR imaging was significantly more sensitive (100% vs. 69%; P less than .01) in the detection of soft-tissue infection. In addition, cellulitis could not be distinguished from soft-tissue abscess on radionuclide studies, whereas MR imaging was 92% accurate in depicting soft-tissue abscesses. Further research is necessary to determine how to relate these findings to true human clinical situations.

Abscess↗
PubMed1987

Infections of the musculoskeletal system: high-field-strength MR imaging.

Twenty-two patients with clinical findings consistent with osteomyelitis, soft-tissue infection, or both were studied with magnetic resonance (MR) imaging at 1.5 T. Another 15 patients with joint effusion but no clinical or laboratory signs of infection served as controls. Soft-tissue abscesses, osteomyelitis, joint and tendon sheath effusion, and cellulitis were well depicted on MR imaging, allowing the correct diagnosis of presence and extent of infection in all but two cases. MR imaging was as sensitive as technetium-99m methylene diphosphonate bone scintigraphy in demonstrating osteomyelitis and was more specific and more sensitive than other scintigraphic techniques in demonstrating soft-tissue infections, primarily because of its superior spatial resolution. Computed tomography, performed in seven cases, was as accurate as MR imaging in demonstrating bone and soft-tissue infections. Infected and noninfected synovial effusions had the same signal intensity, but associated findings such as soft-tissue fluid collections or osteomyelitis made the distinction possible.

Abscess↗
PubMed1984

Rheumatoid factor in otitis media with effusion.

Because of the pathologic similarities between rheumatoid arthritis and otitis media with effusion (OME), rheumatoid factor (RF) was measured in 156 human middle ear effusion (MEE) and serum samples from patients with chronic OME. Using a quantitative latex agglutination test, we were able to demonstrate RF in the MEEs of 85% of patients with OME. Demonstrable RF titers were found in only 8% of the patients' serum samples. The titers of mucoid MEE samples were seven times higher than those observed in serous MEE samples. The presence of RF was not related to the age of the patient, the presence of viable bacteria in the MEEs, or history of OME.

Adolescent↗
PubMed1979

Variations in the virulence of Plasmodium gallinaceum for avian embryos after repeated passages in mosquitos and chickens.

Inoculation of 1 x 10(6) parasites of Plasmodium gallinaceum from chicks infected with sporozoites into 10-day chicken embryos produced infections with wide ranges of peak parasitaemia. It is thought that these variations reflect alterations in the genetic moiety of the parasites after recombinations occurring during the sexual cycle in different batches of mosquitos.

Animals↗