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Biomedical subjects

W A Cohen

Publications and source records attributed to W A Cohen.

At least 19 recordsLinked to original sources
PubMed2001

Withdrawal of support in intracerebral hemorrhage may lead to self-fulfilling prophecies.

BACKGROUND: Withdrawal of support in patients with severe brain injury invariably leads to death. Preconceived notions about futility of care in patients with intracerebral hemorrhage (ICH) may prompt withdrawal of support, and modeling outcome in patient populations in whom withdrawal of support occurs may lead to self-fulfilling prophecies. METHODS: Subjects included consecutive patients with supratentorial ICH. Radiographic characteristics of the hemorrhage, clinical variables, and neurologic outcome were assessed. Attitudes about futility of care were examined among members of the departments of neurology and neurologic surgery through a written survey and case presentations. RESULTS: There were 87 patients with supratentorial ICH; overall mortality was 34.5% (30/87). Mortality was 66.7% (18/27) in patients with Glasgow Coma Score < or = 8 and ICH volume > 60 cm(3). Medical support was withdrawn in 76.7% (23/30) of patients who died. Inclusion of a variable to account for the withdrawal of support in a model predicting outcome negated the predictive value of all other variables. Patients undergoing surgical decompression were unlikely to have support withdrawn, and surgery was less likely to be performed in older patients (p < 0.01) and patients with left hemispheric hemorrhage (p = 0.04). Survey results suggested that practitioners tend to be overly pessimistic in prognosticating outcome based upon data available at the time of presentation. CONCLUSIONS: The most important prognostic variable in determining outcome after ICH is the level of medical support provided. Withdrawal of support in patients felt likely to have a "poor outcome" biases predictive models and leads to self-fulfilling prophecies. Our data show that individual patients in traditionally "poor outcome" categories can have a reasonable neurologic outcome when treated aggressively.

Aged↗
PubMed2001

NHE-RF, a merlin-interacting protein, is primarily expressed in luminal epithelia, proliferative endometrium, and estrogen receptor-positive breast carcinomas.

NHE-RF, a regulatory cofactor for NHE (Na(+)-H(+) exchanger) type 3, interacts with ion transporters and receptors through its PDZ domains and with the MERM proteins (merlin, ezrin, radixin and moesin) via its carboxyl terminus. Thus, NHE-RF may act as a multifunctional adaptor protein and play a role in the assembly of signal transduction complexes, linking ion channels and receptors to the actin cytoskeleton. NHE-RF expression is up-regulated in response to estrogen in estrogen receptor-positive breast carcinoma cell lines, suggesting that it may be involved in estrogen signaling. To further understand NHE-RF function and its possible role in estrogen signaling, we analyzed NHE-RF expression in normal human tissues, including cycling endometrium, and in breast carcinomas, tissues in which estrogen plays an important role in regulating cell growth and proliferation. NHE-RF is expressed in many epithelia, especially in cells specialized in ion transport or absorption, and is often localized to apical (luminal) membranes. NHE-RF expression varies markedly in proliferative versus secretory endometrium, with high expression in proliferative (estrogen-stimulated) endometrium. Furthermore, estrogen receptor status and NHE-RF expression correlate closely in breast carcinoma specimens. These findings support a role for NHE-RF in estrogen signaling.

Adult↗
PubMed2000

Radiologic spectrum of craniocervical distraction injuries.

Injuries to the atlanto-occipital region, which range from complete atlanto-occipital or atlantoaxial dislocation to nondisplaced occipital condyle avulsion fractures, are usually of critical clinical importance. At initial cross-table lateral radiography, measurement of the basion-dens and basion-posterior axial line intervals and comparison with normal measurements may help detect injury. Computed tomography (CT) with sagittal and coronal reformatted images permits optimal detection and evaluation of fracture and luxation. CT findings that may suggest atlanto-occipital injury include joint incongruity, focal hematomas, vertebral artery injury, capsular swelling, and, rarely, fractures through cranial nerve canals. Magnetic resonance (MR) imaging of the cervical spine with fat-suppressed gradient-echo T2-weighted or short-inversion-time inversion recovery sequences can demonstrate increased signal intensity in the atlantoaxial and atlanto-occipital joints, craniocervical ligaments, prevertebral soft tissues, and spinal cord. Axial gradient-echo MR images may be particularly useful in assessing the integrity of the transverse atlantal ligament. All imaging studies should be conducted with special attention to bone integrity and the possibility of soft-tissue injury. Atlanto-occipital injuries are now recognized as potentially survivable, although commonly with substantial morbidity. Swift diagnosis by the trauma radiologist is crucial for ensuring prompt, effective treatment and preventing delayed neurologic deficits in patients who survive such injuries.

Atlanto-Axial Joint↗
PubMed1999

Extravasation of radiographic contrast is an independent predictor of death in primary intracerebral hemorrhage.

BACKGROUND AND PURPOSE: Hematomas that enlarge following presentation with primary intracerebral hemorrhage (ICH) are associated with increased mortality, but the mechanisms of hematoma enlargement are poorly understood. We interpreted the presence of contrast extravasation into the hematoma after CT angiography (CTA) as evidence of ongoing hemorrhage and sought to identify the clinical significance of contrast extravasation as well as factors associated with the risk of extravasation. METHODS: We reviewed the clinical records and radiographic studies of all patients with intracranial hemorrhage undergoing CTA from 1994 to 1997. Only patients with primary ICH were included in this study. Univariate and multivariate logistic regression analyses were performed to determine the associations between clinical and radiological variables and the risk of hospital death or contrast extravasation. RESULTS: Data were available for 113 patients. Contrast extravasation was seen in 46% of patients at the time of CTA, and the presence of contrast extravasation was associated with increased fatality: 63.5% versus 16.4% in patients without extravasation (P=0.011). There was a trend toward a shorter time (median+/-SD) from symptom onset to CTA in patients with extravasation (4.6+/-19 hours) than in patients with no evidence of extravasation (6.6+/-28 hours; P=0.065). Multivariate analysis revealed that hematoma size (P=0.022), Glasgow Coma Scale (GCS) score (P=0.016), extravasation of contrast (P=0.006), infratentorial ICH (P=0.014), and lack of surgery (P<0.001) were independently associated with hospital death. Variables independently associated with contrast extravasation were hematoma size (P=0.024), MABP >120 mm Hg (P=0.012), and GCS score of </=8 (P<0.005). CONCLUSIONS: Contrast extravasation into the hematoma after ICH is associated with increased fatality. The risk of contrast extravasation is increased with extreme hypertension, depressed consciousness, and large hemorrhages. If contrast extravasation represents ongoing hemorrhage, the findings in this study may have implications for therapy of ICH, particularly with regard to blood pressure management.

Adolescent↗
PubMed1999

Follow-up of conservatively managed epidural hematomas: implications for timing of repeat CT.

BACKGROUND AND PURPOSE: Small asymptomatic epidural hematomas (EDHs) are frequently managed nonoperatively with good neurologic outcome. Our goals were to determine the frequency and timing of enlargement of acute traumatic EDHs that are not immediately surgically evacuated as well as to identify factors associated with rehemorrhage. METHODS: Of 252 consecutive patients with acute traumatic EDH who were treated over a 5-year period, 160 were managed nonoperatively. Their CT scans, imaging reports, and medical records were reviewed retrospectively. Parameters analyzed as possible predictors of rehemorrhage during nonoperative management were size of the EDH, presence of an associated fracture, contralateral brain injury, midline shift, coagulopathy, and neurologic and physiological injury as measured by the Revised Trauma Score. We compared discharge discharge disposition as a proxy for neurologic condition at discharge. RESULTS: The EDH enlarged in 37 (23%) of the 160 patients during conservative management. Mean enlargement was 7 mm, and the mean time to enlargement was 8 hours after injury and 5.3 hours after CT diagnostics. EDH enlargement occurred within 36 hours after injury in all cases. Of the parameters analyzed, only a high Revised Trauma Score correlated significantly with EDH rehemorrhage, suggesting that intubation and chemical paralysis may prevent rehemorrhage through the restriction of head movement and the control of blood pressure. The subgroup of patients with rehemorrhage experienced no difference in neurologic outcome despite a higher rate of clinical deterioration. CONCLUSION: EDH enlargement occurs frequently, but early. Repeat imaging with CT is most appropriate within 36 hours after injury.

Acute Disease↗
PubMed1998

High-resolution inter-ictal SPET and phased-array MRI in partial epilepsy: an imaging comparison with video/EEG and outcome correlation.

To assess the clinical utility of high-resolution inter-ictal single photon emission tomography (SPET) of regional cerebral perfusion and high-resolution magnetic resonance imaging (MRI) of the brain with a phased-array temporal lobe coil, 35 patients with presumed partial epilepsy were evaluated prospectively by these techniques in addition to prolonged video/electroencephalographic (EEG) monitoring. Twenty of these patients had surgical treatment of partial epilepsy with outcome determinations spanning from 12 months to 3 years at follow-up. There were four categories of imaging findings as compared to scalp/sphenoidal EEG localization. Category I included 12 patients (34% of total) in whom there was complete imaging and EEG concordance. Category II included 4 patients (11%) in whom MRI and EEG were concordant but SPET was divergent or normal. Category III included 13 patients (37%) in whom SPET and EEG were concordant but MRI was divergent or normal. Category IV included 4 patients (11%) in whom neither SPET nor MRI was concordant with EEG. In this study, the relative sensitivities of SPET and MRI for localization of partial epilepsy based on prolonged scalp/sphenoidal video/EEG recordings were 76% and 49%, respectively. We conclude that these neuroimaging techniques (phased-array MRI and inter-ictal cerebral perfusion SPET) are complementary and useful in the pre-operative evaluation of patients with partial epilepsy.

Adolescent↗
PubMed1998

Imaging of intracranial aneurysms and subarachnoid hemorrhage.

Advances in CT, MR imaging, and catheter angiography provide the radiologist and neurosurgeon with a variety of imaging options for screening, diagnosis, presurgical evaluation, and postoperative monitoring of patients with intracranial aneurysms. Noninvasive imaging techniques have not replaced conventional angiography for the comprehensive evaluation o aneurysms but are effective in screening patients suspected to have an unruptured aneurysm or for preoperative planning in emergency situations that preclude catheter angiography. CT, CT angiography, MR imaging, and MR angiography can all complement the information obtained with catheter angiography in presurgical planning, and the choice of supplemental studies should be individualized. Rotational and intraoperative angiography are problem-solving options used for selected cases at our institution. Continuous improvements in techniques for CT and MR angiography may someday reach the point where surgery can be undertaken on the basis on noninvasive imaging alone, with catheter angiography reserved for endovascular therapy planning and guidance.

Catheterization↗
PubMed1997

Intracranial bacterial infections in patients with AIDS.

Nontuberculous, nonsyphilitic intracranial bacterial infections in HIV-positive individuals may be nonspecific presentations of unusual organisms, such as R. equi, B. henselae, Nocardia sp. or L. monocytogenes. In addition, more common organisms, such as Staphylococcus, Streptococcus, or Salmonella sp. may cause an unusually severe infection. In general, the imaging appearance of these bacterial infections is similar to that in immunocompetent individuals.

AIDS-Related Opportunistic Infections↗
PubMed1996

Neurologic Manifestations of HIV Infection Without AIDS:Follow-UP of a Cohort of Homosexual and Bisexual Men.

To identify neurological abnormalities in HIV infection, 159 HIV-seropositive men without AIDS and 76 seronegative controls underwent standardized general and neurological examinations, lumbar puncture (LP), neuropsychological (NP) assessment, and brain magnetic resonance (MR) imaging. History, physical, and laboratory evaluations were repeated every six months. NP tests (all subjects) and MR imaging (seropositives only) was repeated every 6-12 months; LP (seropositives only) was repeated yearly. Mean follow-up was 24.6 months. Neurological abnormalities, most related to hearing, were seen in 60 (38.2%) of 157 seropositives and 23 (30.3%) of 76 controls at baseline (p = NS). During follow-up, 43 (31.6%) of 136 seropositives had persistent hearing abnormalities compared to 9 (14.1%) of 64 seronegatives (p = 0.008). Seven HIV-seropositives developed peripheral neuropathy; this was more common among those with hearing abnormalities (p = 0.03). HIV-seropositives performed less well on NP tests than controls, but overall performance did not decline. Worsening brain atrophy by MR imaging or cerebrospinal fluid abnormalities are more common in HIV-seropositives than seronegatives and may share a common mechanism with peripheral neuropathy. Further study is needed to determine whether these abnormalities portend more serious neurological disease.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Judicial hanging: postmortem radiographic, CT, and MR imaging features with autopsy confirmation.

PURPOSE: To assess postmortem radiologic and pathologic findings by using modern imaging and autopsy techniques in two recent cases of judicial hangings. MATERIALS AND METHODS: Cervical spine radiography; computed tomography (CT) of the head, neck, and chest; magnetic resonance (MR) imaging of the head and cervical spine; and vertebral angiography were followed by a complete autopsy, including head and neck dissection. RESULTS: The first case (subaural knot) showed cervical spine ligamentous injury and partial disruption of the vertebral arteries without vertebral subluxation or injury to the cervical cord. The second case (submental knot) showed complete ligamentous disruption and subluxation at C2-3 with complete cord transection. In both cases, minimally displaced transverse process fractures were present, and CT and MR imaging of the head showed diffuse subarachnoid hemorrhage. CONCLUSIONS: The extent and distribution of injuries differed markedly in the two cases. The first case involved loss of consciousness probably from subarachnoid hemorrhage or cerebral hypoxia, followed by death due to cerebral anoxia. The second case involved a major spinal cord injury with subarachnoid hemorrhage.

Autopsy↗
PubMed1994

White matter ischemia on brain SPECT.

Four patients were shown to have ischemic injury to the posterior limb of the internal capsule on brain SPECT with 99mTc-HMPAO. These findings were later corroborated by transmission CT scans in three patients. In the interpretation of high-resolution SPECT imaging of regional cerebral blood flow, it is important to inspect the deep white and gray matter activity for asymmetry and perfusion deficits. The blood flow to the diencephalon, which is critical for brain function, can be imaged with high-resolution brain SPECT. The early ascertainment of ischemic changes in the diencephalon may lead to important patient management decisions.

Adult↗
PubMed1993

Viral infections of the CNS in children: imaging features.

In this paper, we review the imaging findings associated with the major viral infections of the CNS in infants and children. We approach these infections by grouping them into several categories: congenital infections in neonates, aseptic meningitis and encephalitis, acute disseminated encephalomyelitis and other postviral syndromes in older children, and HIV infection.

Brain↗
PubMed1992

Brain SPECT and the effect of cerebral angioplasty in delayed ischemia due to vasospasm.

Cerebral vasospasm is a major determinant of outcome after subarachnoid hemorrhage (SAH). Brain SPECT with 99mTc-HMPAO was obtained before and after cerebral angioplasty in 10 patients with delayed ischemia due to vasospasm. Eight patients had clinically evident neurologic improvement after the procedure. Visual interpretation and an internal-reference (cerebellum), manual, semi-quantitative region of interest (ROI) analysis revealed improvement of regional cerebral blood flow (rCBF) in 9 out of 10. There were disagreements between the visual and ROI analysis in the two that did not improve clinically. For all 10, the average increase per anterior circulation vessel dilated (n = 17) was 8.8% by comparison of the corticocerebellar ratios. For the eight that improved, the average increase was 10.5%. Brain SPECT is valuable for evaluating delayed cerebral ischemia caused by vasospasm after SAH and is useful to document the changes in rCBF induced by angioplasty. It is possible that SPECT may be useful to detect critical reductions in perfusion before clinical deficits develop, thereby offering the potential to identify candidates for early treatment with angioplasty.

Adult↗
PubMed1990

Correlation of motor cortex brain mapping data with magnetic resonance imaging.

Brain maps derived intraoperatively from patients undergoing tumor resection were correlated retrospectively with magnetic resonance (MR) images with respect to the precise localization of the motor cortex in an attempt to identify useful preoperative MR imaging landmarks that correspond to functional brain regions. Superior axial T2-weighted MR images consistently localized the central sulcus, whereas parasagittal and farlateral sagittal images readily identified the rolandic (sensorimotor) cortex, as a functional unit, based on the cingulate-marginal sulcus and insula, respectively. It is therefore concluded that multiplanar MR images may serve as a useful preoperative planning aid prior to removing intrinsic brain tumors within or adjacent to the motor cortex.

Brain Mapping↗
PubMed1988

Benign lymphoepithelial parotid cysts and hyperplastic cervical adenopathy in AIDS-risk patients: a new CT appearance.

The contrast material-enhanced computed tomographic (CT) scans of 18 patients at risk for acquired immunodeficiency syndrome (AIDS) who had painless facial swelling were reviewed. All scans demonstrated parotid cysts and diffuse homogeneous cervical adenopathy. The cysts were bilateral in all but three cases. Eleven of 13 patients tested had antibodies to the human immunodeficiency virus (HIV), and two of the five untested patients later developed AIDS. The authors believe that the CT findings of multiple parotid cysts and cervical adenopathy suggest that the patient may be infected with the HIV virus, and the radiologist should alert the referring physician so that appropriate precautions and treatment may be initiated.

AIDS-Related Complex↗
PubMed1987

Pitfalls in the CT diagnosis of atlantoaxial rotary subluxation.

CT was used to examine six patients with clinically evident atlantoaxial rotary fixation, two patients with torticollis, and six normal subjects who had turned their heads to the side as far as voluntarily possible. The CT appearances of the atlantoaxial complex were identical in all three groups. To differentiate these groups, we propose a functional scan through C1-C2 in which patients are scanned initially as they present, with their heads fixed in lateral rotation. Subsequent scans are obtained with their heads turned to the maximum contralateral rotation. CT scans in patients with atlantoaxial rotary fixation demonstrate no motion at C1-C2 during this maneuver, while those in patients with transient torticollis show a reduction or reversal of the rotation of C1 on C2.

Adolescent↗