Lead and zinc dust depositions from ore trains characterised using lead isotopic compositions.

This study investigates an unusual source of environmental lead contamination - the emission and deposition of lead and zinc concentrates along train lines into and out of Australia's oldest silver-lead-zinc mine at Broken Hill, Australia. Transport of lead and zinc ore concentrates from the Broken Hill mines has occurred for more than 125 years, during which time the majority was moved in uncovered rail wagons. A significant amount of ore was lost to the adjoining environments, resulting in soil immediately adjacent to train lines elevated with concentrations of lead (695 mg kg(-1)) and zinc (2230 mg kg(-1)). Concentrations of lead and zinc decreased away from the train line and also with depth shown in soil profiles. Lead isotopic compositions demonstrated the soil lead contained Broken Hill ore in increasing percentages closer to the train line, with up to 97% apportioned to the mined Broken Hill ore body. SEM examination showed ceiling dusts collected from houses along the train line were composed of unweathered galena particles, characteristic of the concentrate transported in the rail wagons. The loss of ore from the uncovered wagons has significantly extended the environmental footprint of contamination from local mining operations over an area extending hundreds of kilometres along each of the three train lines.

The antithrombotic effects of CI-1031 (ZK-807834) and enoxaparin in a canine electrolytic injury model of arterial and venous thrombosis.

Factor Xa is a serine protease positioned at the convergence point of the intrinsic and extrinsic coagulation pathways and is therefore an attractive target in the development of novel anticoagulant drugs. The objective of this study was to evaluate the efficacy of CI-1031 (N-[2-[5-amidino-2-hydroxyphenoxy]-6-[3-(1-methyl-1H-imidazolin-2-yl)-phenoxy]-3,5-difluoropyrid), a potent and selective inhibitor of Factor Xa, in a canine electrolytic injury model of arterial and venous thrombosis. Enoxaparin (enoxaparin sodium), a low molecular weight heparin currently approved for treatment and prevention of deep vein thrombosis and unstable angina, was also tested for efficacy in this model. CI-1031 was administered intravenously to anesthetized dogs at three doses: 1.25, 2.5 and 5 microg/kg/min (n=5 for each group) as a continuous infusion for 5.5 h. The control group (n=5) received a continuous infusion of vehicle (3.69 mmol citric acid and 0.9% sodium chloride solution) at a rate of 1 ml/kg/h. Ninety minutes after administration of CI-1031 prothrombin times increased 1.2-, 1.6- and 2.0-fold over baseline values in the 1.25, 2.5 and 5 microg/kg/min groups, respectively. The time to formation of an occlusive thrombus in the femoral arteries averaged 69+/-5 min in the control group compared to 127+/-19, 192+/-33 and 219+/-15 min in the low-, mid- and high-dose CI-1031 groups. In the femoral veins, occlusion time in the controls averaged 56+/-11 min compared to 153+/-22, 137+/-30 and 214+/-26 min in the three treatment groups. Thrombus weights in the control arteries averaged 51+/-4 mg compared to 45+/-5, 28+/-10 and 15+/-3 mg in the CI-1031 treated groups. On the venous side, control thrombus weights averaged 96+/-18 mg compared to 75+/-16, 51+/-16 and 25+/-4 mg in the low-, mid- and high-dose CI-1031 groups. A plasma CI-1031 concentration of approximately 400 ng/ml was associated with a 50% reduction in thrombus weight relative to control animals. Enoxaparin was administered intravenously at a loading dose of 50, 100 or 200 IU/kg for 1 h followed by a maintenance infusion of 25, 50 or 100 IU/kg/h for 4.5 h. The most dramatic changes in coagulation parameters were observed in thrombin time with virtually no changes in prothrombin time. Enoxaparin elicited a dose-dependent increase in time to thrombotic occlusion and a dose-dependent decrease in thrombus weight similar to that observed with CI-1031. Time to occlusion in the enoxaparin-treated groups averaged 117+/-33, 188+/-32 and 217+/-22 min in the low-, mid- and high-dose groups in the femoral arteries and 84+/-22, 171+/-31 and 133+/-33 min in the femoral veins. Thrombus weights averaged 33+/-10, 12+/-5 and 10+/-4 mg in the arteries and 32+/-9, 13+/-2 and 21+/-6 mg in the veins in the low-, mid- and high-dose groups. Blood loss with CI-1031 tended to be less than enoxaparin at doses that provided comparable efficacy. These results demonstrate that CI-1031, like enoxaparin, is an effective antithrombotic agent in an established canine model of arterial and venous thrombosis. CI-1031 provided dose-dependent efficacy with minimal changes in ex vivo coagulation parameters, suggesting it may be a safe and effective antithrombotic agent for both arterial and venous indications.

A clinicopathological study of 15 patients with neuroglial heterotopias and encephaloceles of the middle ear and mastoid region.

OBJECTIVES/HYPOTHESIS: Heterotopic masses of neuroglial tissue involving non-midline structures, specifically, the middle ear region, are exceptional. The pathogenesis of these lesions and, in particular, their relation to encephaloceles, is uncertain. STUDY DESIGN AND METHODS: H&E-stained sections from 15 lesions diagnosed as neuroglial heterotopias or encephaloceles involving the middle ear region were reviewed. Radiographic or operative evidence of a central nervous system (CNS) relation and clinical factors possibly related to pathogenesis were analyzed. RESULTS: All 15 lesions (from six men and nine women; mean age, 49 y; range, 16-67 y), regardless of their relation to the CNS, were composed of varying proportions of neurons and glia with associated chronic inflammatory cells and reactive gliosis. No significant ependymal or choroid plexus component was present. Operative findings revealed that two lesions had definite CNS connections and two were unrelated to the CNS; this relation could not be determined in the remaining cases. Seven of 10 patients for whom clinical information was available had a history of chronic otitis media or mastoiditis or both; four of these seven patients also had a history of previous trauma or surgery. Three patients, including both patients whose lesions had no demonstrable CNS attachment, had no predisposing factors. CONCLUSIONS: Most neuroglial heterotopias of the middle ear are probably acquired encephaloceles. These lesions occur in older patients than do their midline counterparts. Determination of the relation of these lesions to adjacent CNS structures must be done radiographically or using operative findings, because histology alone cannot be reliably used to render an accurate diagnosis.

Ultrasound: impact on diagnostic peritoneal lavage, abdominal computed tomography, and resident training.

Our objective was to determine the impact of abdominal ultrasound (US) on 1) the use of diagnostic peritoneal lavage (DPL) and abdominal computed tomography (ACT) for diagnosing blunt abdominal trauma (BAT) and on 2) surgical resident training. The study design was a retrospective chart review. Patients sustaining BAT who had ACT or DPL done during the 1-year period before the introduction of US (pre-US) were compared with those from a 1-year period beginning 6 months after US (post-US). Data collected included diagnostic modality, demographic data, mortality, associated injuries, length of stay, mechanism of injury, and number of exploratory laparotomies. Of 128 patients in the pre-US group, 35 patients (27%; P < 0.001) underwent DPL, 0 patients (0%; P < 0.001) received US, and 92 patients (72%) received ACT, with positive results for 31 patients (34%). Exploratory laparotomy was performed on 35 patients (27%) in the pre-US group. Of 140 patients in the post-US group, 8 patients (6%; P < 0.001) underwent DPL, 120 patients (85%; P < 0.001) received US, and 108 patients (77%) received ACT, with positive results for 44 patients (42%). Exploratory laparotomy was performed on 22 patients (15%; P < 0.001) in the post-US group. Resident experience with DPL before and after the introduction of US and availability of US for graduated residents was documented. Chi-square and Fisher's exact test were used for statistical analysis. Resident experience changed from 22 to 3 DPLs per year in the pre- and post-US groups, respectively. Ten per cent of graduating residents had US available for use after leaving this institution. US replaced DPL and resulted in slightly more positive ACT scans in assessing BAT at our institution. Paradoxically, only 10 per cent of graduating residents had US available after leaving this institution. Until the use of US for diagnosing BAT has widespread use in the community, we must question our adequacy of resident preparation for diagnosing BAT.

Dysembryoplastic neuroepithelial tumor: an immunohistochemical study with myelin oligodendrocyte glycoprotein.

CONTEXT: The dysembryoplastic neuroepithelial tumor (DNT) is an uncommon lesion characterized by a heterogeneous population of neurons, astrocytes, and oligodendroglia-like cells (OLCs). The basic nature of the DNT and its constituent cells, particularly the OLCs, remains unresolved; some authors favor a neuronal origin, and others propose a glial or mixed origin for these cells. DESIGN: We examined 11 DNTs with antibodies to myelin oligodendrocyte glycoprotein, a marker of mature oligodendrocytes. RESULTS: All DNTs studied (7 from males, 4 from females; age range of patients, 2-37 years) were composed of varying proportions of neurons, astrocytes, and OLCs. Membrane or cytoplasmic immunoreactivity for myelin oligodendrocyte glycoprotein was found in many OLCs in 9 of 11 cases. The number of myelin oligodendrocyte glycoprotein-positive OLCs was variable: >75% of the OLCs were positive in 5 cases, 25% to 75% of the OLCs were positive in 2 cases, and <25% of the OLCs were positive in 2 cases. CONCLUSION: These findings suggest that many of the OLCs represent mature oligodendrocytes and support the notion that DNTs are heterogenous lesions composed of multiple, mature cell types.

The effects of nursing staff inexperience (NSI) on the occurrence of adverse patient experiences in ICUs.

Although many studies have attempted to define levels of staff experience appropriate for the care of critically ill patients, minimal data is available on the effect of nursing staff inexperience (NSI) on the occurrence of incidents in the intensive care environment. The Australian Incident Monitoring Study in Intensive Care Units (AIMS-ICU), an anonymous, voluntary incident reporting system, can help to identify problems in which NSI may be implicated. NSI may be an incident in itself or contribute to the occurrence of other incidents. The objective of this paper was to identify incidents associated with NSI and estimate their effect on the quality of patient care. Incidents related to NSI were extracted from the AIMS-ICU database and analysed using descriptive methodology. Seven hundred and thirty five reports covering 1,472 incidents were identified as relating to NSI. Of these, 282 were described in the narrative section and 453 were selected as a contributing factor by the reporter. Major categories for the 1,472 incidents included airway and ventilation (317) drugs and therapeutics (468), procedures, lines and equipment (219), patient environment (234) and unit management (234). An undesirable major adverse patient outcome was selected in 20 per cent of reports. NSI associated incidents reported to AIMS-ICU suggest that NSI can have a negative impact on the quality of care delivered to critically ill patients as shown by the occurrence and outcome of incidents related to such inexperience. Errors are more likely to occur when NSI is combined with staff shortage, inadequate supervision and high unit activity. When rostering or employing staff, nurse managers and educators must consider the special requirements of inexperienced nurses. Safe patient care requires these issues be included in discussions about ICU resource allocation.

Cytokeratin 7 and 20 expression in choroid plexus tumors: utility in differentiating these neoplasms from metastatic carcinomas.

Tumors derived from choroid plexus epithelium are uncommon and may exhibit a wide variety of histologic patterns. They often are difficult to distinguish from metastatic carcinomas. Previous studies that addressed this issue yielded conflicting results. Recent reports have demonstrated that evaluation of coordinate expression of cytokeratin (CK) 7 and CK20 aids in distinguishing primary from metastatic lesions in a number of anatomic sites and that tumors that commonly are metastatic to the brain retain their CK7/CK20 immunophenotype in this location. We examined 35 choroid plexus tumors with a panel of antibodies to determine their CK7/CK20 immunophenotype. Tumors from 35 patients (7 male, 28 female; mean age, 25 years), including 31 choroid plexus papillomas and 4 atypical papillomas, were evaluated. All tumors were intraventricular or within the cerebellopontine angle and composed predominantly of orderly columnar epithelial cells resting on distinct fibrovascular cores. Atypical papillomas contained combinations of focal loss of architectural pattern, increased mitotic activity, necrosis, and brain parenchymal invasion. No lesion was unequivocally malignant. Twenty-six tumors (74%), including all atypical papillomas, were CK7 positive and CK20 negative. Two tumors stained with both markers, one stained with CK20 only, and six stained with neither marker. Other findings included expression of glial fibrillary acidic protein in 24 tumors, S-100 protein in 19 tumors, transthyretin in 31 tumors, Ber EP4 in 1 tumor, CAM5.2 in 33 tumors, epithelial membrane antigen in 4 tumors, and pancytokeratin in 27 tumors. Our results indicate that the majority of choroid plexus tumors have a CK7-positive/CK20-negative immunophenotype. This finding may be useful in differentiating these lesions from metastatic carcinomas that have differing CK7/CK20 profiles.

Neoplasms of the spinal cord and filum terminale: radiologic-pathologic correlation.

Intramedullary spinal cord neoplasms are rare, accounting for about 4%10% of all central nervous system tumors. Despite their rarity, these lesions are important to the radiologist because magnetic resonance (MR) imaging is the preoperative study of choice to narrow the differential diagnosis and guide surgical resection. On contrast materialenhanced MR images, intramedullary spinal tumors almost always manifest as expansion of the spinal cord and show enhancement. Syringohydromyelia and cystic lesions are frequently associated with intramedullary tumors. Nontumoral cysts tend to be located at the poles of the tumors and do not enhance on contrast-enhanced MR images, whereas cysts within the substance of the tumor are considered tumoral cysts and typically demonstrate peripheral enhancement. Spinal cord ependymomas are the most common type in adults, and cord astrocytomas are most common in children. Both entities constitute up to 70% of all intramedullary neoplasms. A central location within the spinal cord, presence of a cleavage plane, and intense homogeneous enhancement are imaging features that favor an ependymoma. Intramedullary astrocytomas are usually eccentrically located within the cord, are ill defined, and have patchy enhancement after intravenous contrast material administration. Even with these characteristics, it may not be possible to differentiate these two entities on the basis of imaging features alone. Cord hemangioblastomas are the third most common type of intramedullary spinal tumor. Gangliogliomas commonly extend over more than eight vertebral segments. Paragangliomas and primitive neuroectodermal tumors have an affinity for the filum terminale and cauda equina. Other spinal cord tumors include metastatic disease, which is characterized by prominent cord edema for the size of the enhancing portion, and primary lymphoma.

Intracranial extracerebral neuroglial heterotopia: A case report and review of the literature.

Heterotopic masses of neuroglial tissue are uncommon and most frequently involve extracranial midline structures. We report an unusual case of an intracranial, extracerebral neuroglial heterotopia involving the middle and anterior cranial fossae of a 5-year-old girl who presented with facial asymmetry. The lesion was composed of mature but disorganized gray and white matter admixed with surrounding soft tissues and exhibited histologic features reminiscent of cortical dysplasia. These rare lesions have been postulated to arise from a protrusion of tissue from the neuraxis through a pial defect, from abnormalities in the migration of embryonic neuroepithelial tissue, or from an accessory evagination of the neural tube inferior to the telencephalic vesicles. Regardless of the underlying pathogenic mechanism, these lesions must be histologically distinguished from both teratomas and primary central nervous system neoplasms.

How low is too low, revisited: sentence repetition and AVLT-recognition in the detection of malingering.

Sentence Repetition (SR) and Rey Auditory Verbal Learning Test-Recognition Task (AVLT-R) scores of 5 groups of examinees (severe traumatic brain injury [TBI], mild TBI nonlitigants, normal controls, mild TBI litigants, and actors) were compared with the intent of determining cutoffs for the detection of malingering. Cutoff scores were set below the minimum of the severe TBI group, resulting in a specificity of 100% for both tests. At this level of specificity, the AVLT-R detected 10 of the 20 known actors (50% sensitivity), whereas SR correctly identified 14 of the 20 actors (70% sensitivity). Among litigants with mild injury, 12.24% were identified by the AVLT-R and 6.12% by SR as malingerers. These findings are similar to those found utilizing a variety of other common neuropsychological instruments. Employing commonly used neuropsychological tests as measures of motivation is both practical and clinically useful.

Postmortem diagnosis of cerebral malaria.

Human cerebral malaria is a frequent encephalopathy that occurs in the endemic tropical-subtropical zones. There are a smaller number of imported cases in continental zones where the diagnosis sometimes remains difficult to establish. Fifteen days after the death of a 36-year-old male French citizen in Africa, an investigation to determine the cause of death was conducted. Histologic examination of the brain permitted the diagnosis of cerebral malaria. Because of the popularity of overseas tourism and because this disorder may appear as "sudden death," these victims may be referred to a forensic pathologist. This case demonstrates the role a forensic pathologist may play in determining the cause of death in cerebral malaria.

Central neurocytomas express photoreceptor differentiation.

BACKGROUND: Central neurocytomas are composed of mature neuronal elements, frequently arranged in rosettes similar to those present in pineocytomas. This suggests the possibility of similar patterns of differentiation, including photoreceptor differentiation. The authors analyzed the immunoreactivity of central neurocytomas for retinal S-antigen, neuronal, glial, and neuroendocrine markers. METHODS: Thirty-three central neurocytomas were analyzed with reference to their clinicopathologic characteristics, immunoreactivity, and the possibility that anaplastic histologic features correlated with aggressive clinical behavior. RESULTS: There were 18 male and 15 female patients. The median age at diagnosis was 30 years (range, 3-69 years). All of the tumors with specified location were related to the ventricles. Thirty-two tumors were diagnosed at surgery and 1 at autopsy. Histologic features included mineralization (20 of 33), foci of necrosis (4 of 33), chronic inflammation (4 of 33), ganglion cell differentiation (1 of 33), and lipomatous differentiation (1 of 33). None of the lesions had significant nuclear pleomorphism, mitotic activity, or vascular endothelial proliferation. Immunohistochemistry included expression of synaptophysin (33 of 33), neuron specific enolase (31 of 33), S-100 protein (25 of 33), retinal S-antigen (14 of 24), somatostatin (8 of 27), glial fibrillary acidic protein (4 of 33), neurofilament protein (3 of 22), and leucine enkephalin (1 of 27). At follow-up, 15 of 23 patients were alive an average of 8.1 years (range, 0.91-35.9 years) after surgery. CONCLUSIONS: Central neurocytomas behave as slowly growing neoplasms that remain confined within one or several supratentorial ventricles and are associated with long survival after surgical excision. Malignant forms with aggressive clinical behavior were not found. The neoplastic cells can express photoreceptor differentiation possibly relating central neurocytomas to pineocytomas. Adipocyte differentiation may be present, and the possibility of a relation between the central neurocytoma and cerebellar liponeurocytoma should be entertained.

Air bag-associated injury to a child in the front passenger seat.

We report the case of a 3.5-year-old front seat passenger who suffered significant head and neck injuries as a result of air bag deployment in a collision of <30 mph. These lesions included multiple abrasions of the lower half of the face, nose, forehead, and right ear, torn frenula, conjunctival petechiae, comminuted fractures of the left and right lateral frontal regions and right parietal bone, diastatic fracture of the coronal suture, subgaleal and subarachnoid hemorrhages, cortical contusions, subluxation of the atlantooccipital joint, and fracture of the C4 vertebral body. These lesions are consistent with trauma secondary to the deploying air bag and the head striking the interior of the car. The findings in this case further support the Centers for Disease Control and Prevention (CDC) guidelines of keeping children properly restrained, preferably in the back seat, or as far as possible from air bags.

Acceleration-deceleration injuries to the brain in blunt force trauma.

Blunt force trauma to the stationary head is generally associated with cortical-subcortical injuries located at the site of impact (i.e., coup contusions). We present 2 cases of cerebral contusion injury secondary to falling tree limbs hitting the head, illustrating an exception to this observation. In each case, the most prominent lesions were white matter hemorrhagic contusions similar to those associated with acceleration-deceleration types of injuries characterizing falls or motor vehicle accidents (i.e., contrecoup contusions). The proposed pathogenesis for these observed lesions is a forceful impact resulting in the acceleration of the head and brain of a magnitude comparable with that in a motor vehicle accident or a fall.

Foamy cells with oligodendroglial phenotype in childhood ataxia with diffuse central nervous system hypomyelination syndrome.

Childhood ataxia with diffuse central nervous system hypomyelination syndrome (CACH) is a recently described leukodystrophy of unknown etiology. To characterize the neuropathological features and gain insight as to the pathogenesis of this disorder, we studied cerebral tissue from six patients with the CACH syndrome. Evaluation of toluidine blue-stained, semithin sections of white matter from CACH patients disclosed unusual cells with "foamy" cytoplasm, small round nuclei and fine chromatin. Electron microscopy (EM) revealed cells in the white matter with abundant cytoplasm containing many mitochondria and loosely clustered, membranous structures, but lacking the lysosomal structures seen in macrophages. Further analysis of tissue sections with antibodies and special stains demonstrated that the abnormal cells with abundant cytoplasm labeled with oligodendroglial markers, but did not react with macrophage or astrocytic markers. Double immunolabeling with macrophage and oligodendroglial markers clearly distinguished macrophages from the "foamy" oligodendroglial cells (FODCs). Proteolipid protein (PLP) mRNA in situ hybridization demonstrated PLP mRNA transcripts in a high proportion of oligodendrocytes in CACH patients compared to control patients, and PLP mRNA transcript signal in cells, morphologically consistent with FODCs. Normal and pathological brain control tissues did not contain FODCs. These neuropathological findings will be useful pathological identifiers of CACH, and may provide clues to the pathogenesis of this disorder.