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Biomedical subjects

J C Hoffman

Publications and source records attributed to J C Hoffman.

At least 19 recordsLinked to original sources

Ascending pharyngeal artery-internal jugular vein fistula complicating radical neck dissection.

Arteriovenous fistulae of the ascending pharyngeal artery (AP) and internal jugular vein (IJ) are rare. Only two spontaneous AP-IJ fistulae have been described previously, both of which presented with pulsatile tinnitus. A unique case of an AP-IJ fistula developing after radical neck dissection is described in which the clinical presentation was identical to that of a carotid-cavernous fistula.

Angiography

Magnetic resonance artifact in the postoperative cervical spine. A potential pitfall.

An magnetic resonance imaging artifact that stimulates hypertrophic bone formation is described in patients who have had an anterior cervical discectomy. The magnetic resonance images of 26 patients with anterior cervical discectomy were retrospectively reviewed. Comparison was made to the available concurrent computed tomographic scans, computed tomographic myelograms, and operative reports. A bovine spine was drilled with a drill only at one level and with a metal suction tip in close proximity to the drill at another level, and magnetic resonance images were obtained. Artifact was present in 12 patients and absent in 14; this was confirmed in the 8 patients with comparison studies. Close correlation was seen with the prospective reading of the presence of artifact and operative drill use in the seven patients with available operative reports. The bovine spine model showed no artifact at the drill-only level and significant artifact at the level where the metal suction tip was positioned next to the drill. Small metal flecks were seen grossly at the second level, but not on plain roentgenograms. The metallic magnetic resonance artifact seen in postoperative cervical spines is probably from small bits of metal from the metal suction tip as it occasionally hits the drill. Bone abnormalities seen on magnetic resonance imaging at the level of a previous anterior cervical discectomy may need a cervical computed tomogram to confirm the findings.

Adult

Pituitary adenoma: correlation of half-dose gadolinium-enhanced MR imaging with surgical findings in 26 patients.

Sellar magnetic resonance imaging studies obtained with half doses of gadopentetate dimeglumine (0.05 mmol/kg) were prospectively interpreted and retrospectively rated in 26 patients who subsequently underwent transsphenoidal sellar surgery for suspected pituitary adenoma. Studies included a sagittal scout view followed by a non-contrast-material-enhanced, an immediate postcontrast, and a delayed postcontrast T1-weighted image (obtained at 1.0 or 1.5 T). Ten of 11 confirmed microadenomas were identified prospectively; all were identifiable in retrospect. Macroadenomas (12 cases) were well demonstrated. The high signal intensity of the posterior pituitary and of intrasellar hemorrhage was obscured on postcontrast studies. Delayed images proved unnecessary. This prospective evaluation suggests that a half-dose study is comparable to retrospective studies in which full-dose techniques were used for detection of micro- and macroadenomas. Imaging times are reasonably short, and cost of contrast material is potentially reduced. Confirmation with larger studies is required, and careful endocrinologic and clinical follow-up of nonsurgical patients is necessary.

Adenoma

Magnetic resonance findings in a patient with internuclear ophthalmoplegia. Neuroradiological-clinical correlation.

A 49-year-old female presented with symptoms compatible with internuclear ophthalmoplegia. Magnetic resonance using T2-weighted images showed an eccentric area of high signal intensity in the mid pons corresponding to the right medial longitudinal fasciculus. Magnetic resonance is the method of choice when internuclear ophthalmoplegia is suspected. The findings should be differentiated from the normal central hyperintensity called the "pseudo MLF hyperintensity."

Female

Nuclear and mitotically enhanced epitope.

Salt-extracted proteins of taxol-stabilized microtubules from Chinese hamster ovary cells arrested at mitosis were used to immunize mice for hybridoma production. From a group of related monoclonal antibodies (MAbs), one, C9, recognized an epitope on antigens localized by immunofluorescence microscopy to interphase centrosomes and nuclei. The availability of the nuclear antigen was cell cycle-dependent; however, permeabilization of cells before fixation revealed that the antigen was present throughout the cell cycle. The nuclear antigen was exposed during prophase and was released from the nucleus upon nuclear envelope breakdown filling the cytoplasm of the mitotic cell. Antigenic material re-accumulated at daughter nuclei and was concealed during G1 phase. Detergent extraction of the cytoplasmic antigen from mitotic cells enabled localization of antigens to centrosomes, kinetochores, and the furrowing region/midbody. Immunoblot analysis of cells of a variety of species of origin identified an approximate 250 kD polypeptide as corresponding to the nuclear antigen, whereas polypeptides of 107/117 kD as well as approximately 250 kD accounted for the mitotic cytoplasmic antigens. No polypeptides could be associated with antigens at centrosomes, kinetochores, or midbodies. This MAb joins the antibody preparations previously reported that describe nuclear antigens, or epitopes on antigens, enhanced at mitosis.

Animals

Intracranial ganglioglioma: MR, CT, and clinical findings in 18 patients.

Eighteen cases of pathologically proved intracranial gangliogliomas were reviewed to determine their MR, CT, and clinical characteristics. Seventeen patients were evaluated with contrast-enhanced CT and 14 were studied by MR imaging. Eight tumors were predominantly cystic; half of these demonstrated some contrast enhancement, and five contained calcifications. These cystic gangliogliomas were located, in order of decreasing frequency, in the cerebellum, temporal, frontal, and parietal lobes. Ten tumors were solid; eight of these showed contrast enhancement, and only one contained calcifications. Small cysts were present in one solid mass. Solid gangliogliomas occurred preferentially in the temporal lobes. On MR, the findings were nonspecific and reflected the CT findings. In one patient who received gadolinium-DTPA the lesion did not enhance. Clinically, all patients presented with nonfocal long-standing symptoms and all but three were alive an average of 18 months after the initial diagnosis. Pathologists are recognizing ganglioglioma with increasing frequency, and although its radiographic characteristics vary, it should be included in the differential diagnosis when the above-described findings are encountered.

Adolescent

Primary cerebral neuroblastoma: CT and MR findings in 12 cases.

A retrospective CT, MR, and clinical study was performed in 12 patients, five children and seven adults, with histologically proved primary CNS neuroblastoma. The CT and MR appearances of this neoplasia were more variable than generally recognized. Although seven tumors were predominantly intraparenchymal masses with calcification and cyst formation, five were intra- or juxtaventricular. CT was preferable to noncontrast MR both at initial diagnosis and follow-up for identification of calcification, recurrent tumor at surgical sites, and leptomeningeal disease. Noncontrast MR was useful primarily for localization of peri- and intraventricular lesions. We conclude that primary CNS neuroblastoma has a more variable radiographic appearance than is generally recognized, and that an intra- or periventricular epicenter is common.

Adult

Duplex Doppler sonography of the carotid artery: false-positive results in an artery contralateral to an artery with marked stenosis.

Anecdotal reports have described a false-positive "jet effect" or velocity increase in the carotid artery contralateral to an artery with significant stenosis or occlusion when using duplex Doppler sonography. In this study, the frequency, significance, and possible reasons for this finding were evaluated by a retrospective comparison of duplex sonography and angiography. Twenty-three patients with unilateral 81-100% carotid artery stenosis who underwent both duplex sonography (16 Acuson, seven Quantum) and angiography were evaluated. In 14 patients, there was an accurate or slight underestimate (less than 20%) of stenosis present in the internal carotid artery contralateral to an artery with tight stenosis/occlusion. In nine, a velocity increase in the internal carotid artery resulted in overestimation (10-80%) of the actual degree of stenosis. In one of these nine patients, real-time images were sufficient to explain the velocity increase on the basis of vessel tortuosity. In one, falsely elevated velocity resulted from inaccurate assignment of the Doppler angle of incidence in a patient in whom real-time visualization of a distal internal carotid lesion was poor. In four of the nine patients, cross filling via the circle of Willis toward the side of greater stenosis occurred. However, seven of 14 patients in whom there was duplex sonography/angiography agreement or slight duplex sonography underestimation also had cross filling. Vertebral artery patency did not correlate well with the presence of a "jet effect." These findings suggest that an increase in blood flow velocity with duplex Doppler sonography in the internal carotid artery on the side opposite an artery with a tight stenosis is a common source of error and is not readily explained by angiographic evidence of collateral flow.

Aged

Eddy-current-induced artifacts caused by an "MR-compatible" halo device.

Traction or halo devices thought to be compatible with magnetic resonance (MR) imaging and made of nonferromagnetic metals may actually cause MR image artifacts. The authors have observed such artifacts caused by eddy currents generated in the conducting frame of the device by the radio-frequency excitation field. The severity of the artifact depends on the orientation of the device in the MR unit and can be effectively eliminated by disrupting the electrical continuity of the supporting frame of the device.

Diagnostic Errors

Hemorrhage within pituitary adenomas: how often associated with pituitary apoplexy syndrome?

To determine the clinical significance and specificity of suspected intratumoral hemorrhage in pituitary adenomas, we reviewed the clinical presentations, CT results, and findings at surgery in 12 patients who had hyperintense signal within intrasellar and suprasellar masses on short TR/TE spin-echo MR pulse sequences. Eight of the cases were confirmed at surgery. In seven of the operated cases, hemorrhage was found within pituitary adenomas and in the eight case there was hemorrhage but no identifiable adenomatous tissue. Nine of the 12 patients had CT scans; three had focal areas of increased attenuation, four had focal areas of decreased attenuation, and two had uniform hypoattenuation. All nine of these CT abnormalities correlated with areas of hemorrhage on MR. Three patients had clinical apoplexy; in two there was increased attenuation on CT and in one it was decreased. We found that intratumoral hemorrhage may be seen without clinical evidence of pituitary apoplexy, and that the areas of hemorrhage can appear as low attenuation on CT. CT may be better for visualizing intratumoral hemorrhage within the first few days, but MR is more sensitive in detecting and following the hemorrhage in the subacute stage.

Adenoma

Neurological complications of human immunodeficiency virus infection in patients with lymphadenopathy syndrome.

To determine if there is a relationship between neurological abnormalities and human immunodeficiency virus (HIV) infection in patients with lymphadenopathy syndrome (LAS), we studied 39 homosexual/bisexual men with LAS (mean duration of LAS, 4.1 years) and 38 homosexual/bisexual men who were seronegative for HIV (controls). Six LAS patients had histories of symptoms suggesting mononeuropathy, 9 had symptoms suggesting distal symmetrical polyneuropathy, and 9 had histories of herpes zoster radiculitis. Overall, significantly more LAS patients (18) than controls (3) had histories of symptoms or signs of neurological abnormality (odds ratio, 10.0; p = 0.0003). By neuropsychological assessment, 9 of 18 LAS patients and 2 of 26 controls were abnormal (odds ratio, 12.0; p = 0.004). Of those abnormal on the neuropsychological assessment, the majority scored in the mildly impaired range. Magnetic resonance imaging was abnormal in 1 LAS patient and in 1 control. Neither neurological nor neuropsychological abnormalities correlated with duration of LAS, absolute T-helper lymphocyte count, or T-helper/T-suppressor lymphocyte ratio. These results indicate an association of neurological and neuropsychological abnormalities with HIV in patients with LAS. They suggest that mild neurological abnormalities in LAS are common and that HIV may directly or indirectly be the cause.

AIDS-Related Complex

Neurological symptoms and neuropsychological abnormalities in lymphadenopathy syndrome.

This case-control study of 39 homosexual or bisexual men who were human immunodeficiency virus (HIV)-seropositive and had lymphadenopathy syndrome and 38 HIV-seronegative homosexual or bisexual men indicates an association between neurological and neuropsychological abnormalities and HIV infection in patients with lymphadenopathy syndrome.

AIDS-Related Complex

Spinal abnormalities in pediatric patients: MR imaging findings compared with clinical, myelographic, and surgical findings.

Eighty-one pediatric patients with a variety of spinal disorders, including suspected dysrhaphism, scoliosis, neoplasia, and neurofibromatosis, underwent magnetic resonance (MR) imaging. The results were retrospectively compared with those of myelography followed by computed tomography (CT) and surgery. In patients with dysrhaphism, most abnormalities, including hydromyelia, inclusion tumors, and sites of cord tether, were demonstrated with MR imaging. Diastematomyelia and small hydromyelic cavities were indistinguishable on routine coronal and sagittal T1-weighted images; axial images with T2 weighting were optimal for this differentiation. MR imaging did not enable direct visualization of a thickened filum or evaluation of tethering with a thin, dorsally positioned neural placode. Congenital or severe scoliosis required lengthy studies with multiple planes of imaging or myelography and CT. Milder curvatures were readily evaluated with MR imaging, and neoplastic lesions, with the exception of intrathecal tumor seeding, were adequately defined.

Adolescent

Parotid masses: MR imaging.

Twenty patients with surgically proved neoplasms of the parotid gland were evaluated in order to compare contrast material-enhanced computed tomography (CT) and magnetic resonance (MR) imaging. In 14 patients both CT and MR imaging examinations were performed, while in six only MR imaging was performed. Because contrast resolution is better with MR imaging, it appears to be superior to CT in distinguishing the parotid gland from surrounding structures. Four intraparotid lesions were more conspicuous on T2-weighted MR images than on CT scans. MR imaging appears to be superior to CT for evaluating parotid masses and for distinguishing neoplasms of the parotid gland from those originating within the parapharyngeal space.

Adenoma

MR imaging of pituitary adenoma: CT, clinical, and surgical correlation.

Twenty-five patients with suspected pituitary adenoma were evaluated prospectively with CT and MR. Nine patients underwent transsphenoidal surgery, and three of these showed a documented decrease in size of mass on bromocriptine therapy. CT was more sensitive than MR for detecting focal lesions (seven vs three) and sellar-floor erosion (12 vs six). MR was superior to CT in identifying infundibular abnormalities (seven vs six), focal abnormalities of the diaphragma sellae (10 vs seven), cavernous sinus invasion (four vs two), and optic chiasm compression (six vs zero). Thus, MR may be the procedure of choice for optimal identification and localization of macroadenoma. For patients with suspected microadenoma, however, this preliminary series indicates that CT remains the radiographic procedure of choice.

Adenoma

Sinus pericranii. A case report.

A 7-month-old male presented with a 2 X 3 cm soft tissue mass overlying the right mastoid bone. An underlying bony defect was palpable. Plain skull films, CT scan and cerebral arteriogram showed the classic radiologic findings of a sinus pericranii. This rare vascular anomaly is briefly discussed.

Cranial Sinuses

The transformation-related protein p53 is not bound to the SV40 T antigen in BALB 3T12 cells expressing T antigen.

In most murine cells transformed by the SV40 virus, virtually all of the cellular phosphoprotein p53 is in a complex with the SV40 T antigen. Here, we report that, in SV40-infected T-antigen-positive Balb 3T12 mouse cells, most (approximately 80%) of the p53 is not in complex. Complex formation was determined by measuring the amounts of [35S]methionine-labeled p53 which coprecipitated with T antigen when using monoclonal antibody to T antigen. The amount of complex formation was expressed as a percentage of total p53 present, measured by the amount of p53 precipitated with the monoclonal antibody to the p53. The values were confirmed by Western blotting procedure, in which the steady-state levels of the proteins were measured. In these measurements after complete precipitation with antibody to T antigen, the residual p53 in the supernatant was precipitated by antibody to p53, and this amount was denoted as free p53. There was no significant difference seen between the [35S]methionine-labeled tryptic peptides of complexed and the free p53 (or between complexed and free T antigens) as determined by two-dimensional gel electrophoresis and chromatography. Virus rescue experiments and retransformation by the rescued virus showed that there was no mutation in the SV40 DNA coding for the T antigen which could account for the lack of complex formation. Both p53 and T antigen were underphosphorylated in cells which exhibited reduced complex formation. Tumorigenicity in syngeneic mice and anchorage-independent cell growth in culture of various cloned mouse cells with or without T antigen expression was compared. The changes in the biologic properties were explainable solely on the basis of known or expected effects of expression of the T antigen and were independent of complex formation or of absence of complex formation between p53 and T antigen.

Animals