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Biomedical subjects

R B McGhee

Publications and source records attributed to R B McGhee.

At least 19 recordsLinked to original sources
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↗
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↗
PubMed1976

Immunologic and electrophoretic characteristics of two species of Crithidia.

Crithidia harmosa and Crithidia fasciculata were compared immunologically by the indirect fluorescent antibody (FA) method and by agglutination. The FA technic yielded more specific results with cellular-debris than with whole-cell antigens. The immune sera collected from chickens 9 days after the last inoculations with whole-cell antigens had higher homologous titers than those collected after 4 days. Major antigenic differences between the 2 species were revealed by both methods. The electrophoretic patterns of C. harmosa and C. fasciculata obtained by polyacrylamide gel slab electrophoresis differed in the numbers and relative mobilities of their component bands.

Agglutination↗
PubMed1976

Fine structure of Plasmodium gallinaceum in embryonic and neonate chicks.

The erythrocytic stages of Plasmdoium gallinaceum in chicken embryos injected with parasited blood either from a syringe-passaged infection in chickens or from a chicken infected with sporozoites were characterized by abnormal structure. Particularly evident were large, unstained vacuoles within the cytoplasm; these occurred with greatest frequency in schizonts. The presence of myelin bodies within these vacuoles was revealed by transmission electron microscopy; abnormal cytokinesis and aberrant merozoites provided additional evidence of the parasite's inability to develop naturally within the milieu of the embryonic erythrocytes. Fifty-five passages were necessary to restore normal structure of the parasites in embryos, while only 5 passages were required for such restoration in neonate chicks. The probable adaptation of the parasite to the proportions of hemoglobin of the adult chicken may be responsible for the abnormal growth in the immature host.

Animals↗