In situ monitoring of artificial aging and solution heat treatment of a commercial Al-Mg-Si alloy with a high intensity positron beam.

Microstructural changes of a commercial Al-Mg-Si alloy were studied during artificial aging by in situ Doppler broadening spectroscopy using a high-intensity positron beam. The in situ positron annihilation characteristics at high temperatures differ considerably from the conventionally applied ex situ measurements at low temperatures. Therefore, a more comprehensive view of precipitation processes in Al-Mg-Si alloys is obtained. Further, in situ positron-electron annihilation techniques allow for an investigation of aging processes with increased sensitivity. For the artificial aging temperatures of 180 °C and 210 °C pronounced variations of the Doppler broadening S-parameter reveal (i) the evolution of clusters into larger precipitates and (ii) the time of the formation of [Formula: see text]" precipitates and the role of vacancies in connection to this. Towards higher aging times, the transformation from coherent [Formula: see text]" to semi-coherent [Formula: see text]' precipitates could be verified. Additional insights are gained by in situ measurements of the S-parameter during the solution heat treatment of the previously overaged sample. Here, the S-parameter reveals both the dissolution of precipitates starting from temperatures of 364 °C and the thermal generation of vacancies.

MIB-1 staining index of pediatric meningiomas.

OBJECTIVE: For adult meningiomas, the staining index (SI) for the anti-Ki-67 monoclonal antibody MIB-1 is well correlated with histological atypia and tumor recurrence. MIB-1 SIs for meningiomas in the pediatric population have not been previously reported. Meningiomas tend to be more histologically aggressive and to recur more frequently in children, compared with adults. The objectives of this study were to determine whether MIB-1 SIs are correlated with pathological atypia and recurrence among pediatric meningiomas and to compare the MIB-1 SIs of pediatric meningiomas with those of adult meningiomas. METHODS: MIB-1 SIs were assessed on paraffin-embedded sections of 14 pediatric meningiomas (patient age, 2-17 yr), 5 of which contained atypical or malignant features. For comparison with benign pediatric meningiomas, MIB-1 SIs were also assessed on paraffin-embedded sections of 14 adult meningiomas (patient age, 38-90 yr), none of which displayed atypical or malignant features or recurred within a 5-month median follow-up period. RESULTS: MIB-1 SIs of pediatric meningiomas ranged from 1.2 to 31.6% (median, 9.1%). Significant differences were observed between the MIB-1 SIs for tumors with atypical or malignant features (median, 12.3%; range, 7.0-31.6%) and those for tumors without atypia (median, 7.0%; range, 1.2-12.6%; P = 0.045). There were six recurrences after gross total resection, during a 36.5-month median follow-up period. All five of the tumors with pathological atypia recurred; one tumor without atypia recurred. Significant differences were observed between MIB-1 SIs for nonrecurrent tumors (median, 6.6%; range, 1.2-12.2%) and those for recurrent tumors (median, 12.5%; range, 7.0-31.6%; P = 0.012). The median MIB-1 SI for adult control specimens was 8.8% (range, 1.2-19.3%), which did not differ significantly from that for pediatric meningiomas without atypia (P = 0.68). CONCLUSION: For this cohort of pediatric meningiomas, pathological atypia and the tendency to recur were correlated with elevated MIB-1 SIs. The median MIB-1 SI for pediatric meningiomas without histological atypia did not differ significantly from that for adult meningiomas without atypia, suggesting that the more aggressive clinical features of meningiomas in children may be attributable to factors other than the rate of cellular proliferation.

Concurrent acute lymphoblastic leukemia and juvenile pilocytic astrocytoma in a pediatric patient.

The concurrence of acute lymphoblastic leukemia (ALL) and an asymptomatic juvenile pilocytic astrocytoma is described. A 6-year-old boy without clinical evidence of neurofibromatosis had a juvenile pilocytic astrocytoma diagnosed on radiologic examination and before treatment of acute pre-B cell lymphoblastic leukemia. The patient has had a partial resection of the astrocytoma and is 9 months into treatment of his ALL, which is in complete remission. p53 gene mutation was not identified in this patient. The concurrent diagnosis before treatment of ALL and juvenile pilocytic astrocytoma, the latter normally an indolent tumor, suggests that some cases of astrocytoma previously ascribed to radiotherapy or other treatment may in fact be caused by other factors.

Lipid-laden macrophages in the tracheal aspirate of ventilated neonates receiving Intralipid: A pilot study.

Lipid-laden macrophages (LLM) in tracheal aspirates are reported to be pathognomonic findings in exo- and endogenous lipoid pneumonia in adults. A pilot study was carried out to evaluate the effect of lipid infusion on the LLM index of the tracheal aspirates from ventilated neonates. All intubated infants were eligible for the study. Infants receiving parenteral nutrition had intravenous (IV) lipid introduced by 4-7 days of age; most samples after 7 days were from infants receiving IV lipid. Four infants received minimal gastric feeding; none had evidence of aspiration pneumonia. Tracheal aspirates from 28 infants were analyzed for the LLM index. Alveolar macrophages were graded 0-4 in direct relation to the amount of lipid per cell. One hundred macrophages were graded; the maximum possible LLM index was 400. Two hundred forty-five of 387 tracheal aspirate samples were acceptable for analysis. LLM indices increased during the first week after birth; the mean LLM index then continued in the same range, but with a wide distribution of individual values. The mean LLM index from infants receiving an IV lipid infusion during days 4-7 was 87.9 (SD = 44.8), and was significantly higher compared to 58.7 (SD = 40.8) in infants receiving no IV lipid (P < 0. 003). Tracheal aspirates from infants with and without IV lipid infusion yielded many LLM index values >100. These observations invalidate the use of the LLM index >100 as proof of aspiration pneumonia in this group of infants.

Unique desmoplastic cerebral tumor in a patient with complex partial seizures.

Primary brain tumors with prominent desmoplasia include the gliofibroma, desmoplastic infantile ganglioglioma (DIG), pleomorphic xanthoastrocytoma (PXA), and desmoplastic cerebral astrocytoma. In the present report, we describe unusual pathological appearances in two successive resections of a left temporal tumor in a patient with complex partial seizures. Both tumors showed focal astroglial and very prominent neuronal differentiation. In the first resection at age 11 years, the tumor showed only focal desmoplastic areas and prominent neuronal differentiation with bizarre atypical giant cells. In the second resection at age 14 years, the morphology was dramatically different. Now the tumor showed marked desmoplasia with tumor cells coexpressing neuronal and glial markers. Electron microscopy showed prominent neuronal differentiation in both resections and presence of basal lamina around tumor cells. Our case represents a unique example of an extraordinary degree of neuronal differentiation in a desmoplastic cerebral tumor. While cellular pleomorphism in a desmoplastic tumor traditionally suggests the diagnosis of PXA, we wish to underscore that many cells exhibiting marked cytologic atypia may in fact be of neuronal rather than of glial origin as in our case.

Agonist narcotics.

Pain management has been shown to be an area that has been neglected in health care. Health care professionals need to become educated in the importance of addressing and managing pain. Narcotic pain relievers carry many negative connotations to both patients and health care staff. While there are many non-pharmacologic methods of pain management that should be incorporated into patient care, medication management is an area with which we must be comfortable.

Perianal ependymoma presenting in the neonatal period.

Extraspinal ependymomas are a rare type of glioma that may arise in the sacrococcygeal region, presenting as a pelvic mass in an infant or child. Ependymoma presenting in the newborn period has not been described previously. Herein we describe a case of a newborn boy who presented with a perianal ependymoma, which was subsequently found to have presacral extension. The major diagnostic challenge this case presented was to rule out the alternative diagnosis of sacrococcygeal teratoma or a developmental malformation/heterotopia.

Case report: congenital retroperitoneal fibrosarcoma.

We report a case of congenital retroperitoneal fibrosarcoma presenting in a 17-day-old male in which surgical tumor debulking was followed by chemotherapy. His clinical course was complicated. Intraoperatively, 80% of the tumor was removed and he experienced massive blood loss and significant cardiac arrhythmias. Following surgery he received chemotherapy and suffered life-threatening hepatic, hematological and gastrointestinal toxicity. The treatment resulted in clinical remission after 9 months of follow-up. A review of the current literature revealed the changing opinion of the optimal treatment of fibrosarcomas in children. Chemotherapy is playing an increasingly important role in the treatment of fibrosarcoma, both preoperatively and postoperatively.

Omental-mesenteric inflammatory pseudotumor. Cytogenetic demonstration of genetic changes and monoclonality in one tumor.

BACKGROUND: Extrapulmonary inflammatory pseudotumor (plasma cell granuloma) is an uncommon lesion in adults and children, and little is known either of its etiology or clinical characteristics. However, it remains a significant source of morbidity to patients and confusion to clinicians. METHODS: Case reports are presented of three patients with intraabdominal inflammatory pseudotumor who recently underwent surgery. A review of the recent world literature is also presented. Clinical and laboratory characteristics of omental-mesenteric inflammatory pseudotumor are reviewed along with a discussion of its etiology. RESULTS: Cytogenetic data from cells of one patient show a derivative chromosome evolved from a translocation between the long arm of chromosome 2 and the short arm of chromosome 9 [(2;9)(q1,3;p2,2)]. CONCLUSIONS: The lesion is monoclonal, and genetic changes may play a crucial role in the development of this neoplasm. Omental-mesenteric inflammatory pseudotumor appears to represent a distinct clinicopathologic entity as a benign neoplasm in children.

Brain damage from 125I brachytherapy evaluated by MR imaging, a blood-brain barrier tracer, and light and electron microscopy in a rat model.

Changes in normal rat brain were studied acutely, and at 3, 6, 9, and 12 months following interstitial brachytherapy with high-activity 125I seeds. An 80-Gy radiation dose was administered to an area with a 5.5-mm radius. Effects were measured with magnetic resonance (MR) imaging (with and without gadolinium enhancement), leakage of horseradish peroxidase (HRP), electron microscopy, and light microscopy. Significant histological damage was seen at radiation doses above 295 Gy, and breakdown of the blood-brain barrier was observed only in tissue receiving a dose of 165 Gy or greater. Blood-brain barrier breakdown increased up to the 6-month time point, and thereafter appeared to stabilize or decrease. The area of blood-brain barrier disruption indicated by gadolinium-enhanced MR imaging was greater than that indicated by leakage of HRP.

Cortical-basal ganglionic degeneration.

We report our experience with 15 patients believed to have cortical-basal ganglionic degeneration. The clinical picture is distinctive, comprising features referable to both cortical and basal ganglionic dysfunction. Characteristic manifestations include cortical sensory loss, focal reflex myoclonus, "alien limb" phenomena, apraxia, rigidity and akinesia, a postural-action tremor, limb dystonia, hyperreflexia, and postural instability. The asymmetry of symptoms and signs is often striking. Brain imaging may demonstrate greater abnormalities contralateral to the more affected side. Postmortem studies in 2 patients revealed the characteristic pathologic features of swollen, poorly staining (achromatic) neurons and degeneration of cerebral cortex and substantia nigra. Biochemical analysis of 1 brain showed a severe, diffuse loss of dopamine in the striatum. This condition is more frequent than previously believed, and the diagnosis can be predicted during life on the basis of clinical findings. However, as with other "degenerative" diseases of the nervous system, a definitive diagnosis of cortical-basal ganglionic degeneration requires confirmation by autopsy.

Intradural granulocytic sarcoma presenting as a lumbar radiculopathy. Case report.

Granulocytic sarcoma usually occurs in the setting of leukemia and myeloproliferative disorders. Rarely, it can occur in isolation at various anatomical sites without hematological evidence of leukemia. The unique case of an elderly man presenting with right L2-3 radiculopathy is described. Intradural granulocytic sarcoma of the L-2 and L-3 nerve roots with extradural extension was found at surgery and he was treated with incomplete resection and antileukemic chemotherapy. Local recurrence at 3 months was treated with irradiation. Granulocytic sarcoma is frequently misdiagnosed and invariably progresses to acute leukemia. The chloroacetic acid esterase, granulocytic immunohistochemical markers, and electron microscopy appearance can aid in diagnosis. The prognosis is improved with initial aggressive antileukemic chemotherapy and local irradiation.

High-resolution MR imaging of the cadaveric human spinal cord: normal anatomy.

The purpose of this study was to demonstrate the regional MR anatomy of a normal human spinal cord under near optimal conditions. A spinal cord and meninges were excised and segments from the cervical (C6), thoracic (T6), lumbar (L3), and sacral/cauda equina regions were examined on a 2-T MR system. By using a 2.5 x 2.0 cm solenoid coil and a multislice spin-echo sequence, we achieved a resolution of 58 microns in the readout direction and 117 microns in the phase-encode direction. Histological sections corresponding to the areas imaged by MR were retained and treated with stains that demonstrated the distributions of collagen (hematoxylin, phloxine, saffron), myelin (Luxol fast blue/H and E), or neuritic processes (Bielschowsky's). Subarachnoid vascular, white matter, and gray matter structures were demonstrated by MR and light microscopy. The resulting MR images and photomicrographs were correlated. Different signal intensities were observed in the gracile and cuneate fasciculi, and these differences were similar to the pattern seen with the myelin stain. Decreased signal intensity was present in the region of the spinocerebellar tracts. The anatomic detail demonstrated by this study was clearly superior to that shown by clinical MR examinations.

Intervertebral disc embolization resulting in spinal cord infarction. Case report.

A case of spinal cord infarction resulting from embolization of fibrocartilaginous intervertebral disc material is presented. Cases from the literature are reviewed and the theories of pathogenesis are discussed, in all reported cases the diagnosis was not made until postmortem examination.

Subependymoma of the thoracolumbar cord. Case report.

Subependymomas are benign, usually asymptomatic, intraventricular tumors, the origin of which remains controversial. Spinal cord subependymomas are rare: a literature review yields 10 previous cases which are critically appraised in this report. A case of thoracolumbar intramedullary subependymoma is reported, and the histology, ultrastructure, and pre- and postoperative management are reviewed. Awareness that subependymomas may occur as a separate entity in the spinal cord should lead to increased frequency of diagnosis and a better understanding of the biological behavior of these tumors.

Brain tumours presenting with tias and strokes.

A review of 905 consecutive cases of pathologically confirmed brain tumour yielded 25 cases in which the initial presentation strongly suggested the diagnosis of occlusive cerebrovascular disease. Most of these 25 patients were admitted through the emergency department of our hospital and referred to the general medical service for investigation. Nineteen cases of transient ischemic attack and six cases of completed stroke were found in 12 cases of glioblastoma, seven of meningioma, two of metastatic renal cell carcinoma, and one case each of malignant astrocytoma, low-grade astrocytoma, oligodendroglioma, and metastatic squamous cell carcinoma. We document the clinical overlap between neoplastic and vascular syndromes, and stress the need for "tumour awareness" in the work-up of patients presenting to non-neurological practitioners with the clinical picture of occlusive cerebrovascular disease.

Microsurgical resection of solitary intramedullary spinal cord metastases.

Two cases of solitary intramedullary spinal cord metastasis treated primarily by surgical excision are presented. It has been generally thought that appropriate management for the rare metastasis within the spinal cord is radiation and corticosteroids. The excellent palliative results obtained in our patients suggest that, in selected cases, surgical removal is technically feasible and can be of considerable benefit to the patient.