OSIRIS-REx Contamination Control Strategy and Implementation.

OSIRIS-REx will return pristine samples of carbonaceous asteroid Bennu. This article describes how pristine was defined based on expectations of Bennu and on a realistic understanding of what is achievable with a constrained schedule and budget, and how that definition flowed to requirements and implementation. To return a pristine sample, the OSIRIS-REx spacecraft sampling hardware was maintained at level 100 A/2 and <180 ng/cm2 of amino acids and hydrazine on the sampler head through precision cleaning, control of materials, and vigilance. Contamination is further characterized via witness material exposed to the spacecraft assembly and testing environment as well as in space. This characterization provided knowledge of the expected background and will be used in conjunction with archived spacecraft components for comparison with the samples when they are delivered to Earth for analysis. Most of all, the cleanliness of the OSIRIS-REx spacecraft was achieved through communication among scientists, engineers, managers, and technicians.

Beta-amyloid peptide expression is sufficient for myotube death: implications for human inclusion body myopathy.

Inclusion body myositis (sIBM) is the most common disorder of skeletal muscle in aged humans. It shares biochemical features with Alzheimer's disease, including congophilic deposits, which are immunoreactive for beta-amyloid peptide (Abeta) and C'-terminal betaAPP epitopes. However, the etiology of myofiber loss and the role of intracellular Abeta in IBM is unknown. Here we report correlative evidence for apoptotic cell death in myofibers of IBM patients that exhibit pronounced Abeta deposition. HSV-1-mediated gene transfer of Abeta(42) into cultured C2C12 myotubes resulted in a 12.6-fold increase in dUTP-labeled and condensed nuclei over nonexpressing myotubes (P < 0.05). The C'-terminal betaAPP domain C99 also induced myotube apoptosis, but to a significantly lesser extent than Abeta. Apoptosis specific to Abeta-expressing myotubes was also demonstrated through DNA fragmentation, decreased mitochondrial function and the loss of membrane phospholipid polarity. Myotubes laden with Abeta(42), but not other transgene products, developed cytoplasmic inclusions consisting of fibrillar material. Furthermore, injection of normal mouse gastrocnemius muscle with HSV-encoding Abeta cDNA resulted in TUNEL-positive myofibers with pyknotic nuclei. We conclude that Abeta is sufficient to induce apoptosis in myofibers both in vivo and in vitro and suggest it may contribute to myofiber loss and muscle dysfunction in patients with IBM.

Venlafaxine extended release (XR) for the prophylaxis of migraine and tension-type headache: A retrospective study in a clinical setting.

OBJECTIVE: To assess the efficacy of extended-release venlafaxine in the prophylaxis of migraine and chronic tension-type headache. BACKGROUND: Venlafaxine, a structurally novel antidepressant, is a selective serotonin-norepinephrine reuptake inhibitor. This study is the first to test the effects of extended-release venlafaxine on headaches. METHODS: Patients were evaluated on a retrospective basis. Fifty-six patients with chronic tension-type headache and 114 patients with migraine were prescribed extended-release venlafaxine. Nearly all the study subjects had been resistant to several previous preventive medications. Patients took venlafaxine for an average of 6 months with a median dose of 150 mg (range, 37.5 to 300 mg). RESULTS: The mean frequency of headaches in the group with chronic tension-type headache fell from 24.0 to 15.2 per month (P <.0001). The group with migraine showed a reduction from 16.1 to 11.1 headaches per month (P <.0001). The medicine was well tolerated. CONCLUSIONS: This trial indicates that extended-release venlafaxine has potential in headache prophylaxis based on its efficacy and safety profile. We recommend a double-blind, placebo-controlled study to further assess the role of extended-release venlafaxine in headache prevention.

A case of Balamuthia mandrillaris meningoencephalitis.

Balamuthia mandrillaris is a newly described pathogen that causes granulomatous amebic encephalitis, an extremely rare clinical entity that usually occurs in immunosuppressed individuals. We report a case of pathologically proven Balamuthia encephalitis with unusual laboratory and radiologic findings. A 52-year-old woman with idiopathic seizures and a 2-year history of chronic neutropenia of unknown cause had a subacute illness with progressive lethargy, headaches, and coma and died 3 months after the onset of symptoms. Cerebrospinal fluid (CSF) glucose concentrations were extremely low or unmeasurable, a feature not previously described (to our knowledge). Cranial magnetic resonance imaging scans showed a single large temporal lobe nodule, followed 6 weeks later by the appearance of 18 ring-enhancing lesions in the cerebral hemispheres that disappeared after treatment with antibiotics and high-dose corticosteroids. The initial brain biopsy specimen and analysis of CSF samples did not demonstate amebae, but a second biopsy specimen and the postmortem pathologic examination showed Balamuthia trophozoites surrounded by widespread granulomatous inflammation and vasculitis. The patient's neutropenia and antibiotic use may have caused susceptibility to this organism. Amebic meningoencephalitis should be considered in cases of subacute meningoencephalitis with greatly depressed CSF glucose concentrations and multiple nodular lesions on cerebral imaging. Arch Neurol. 2000;57:1210-1212

Definitive classes of childhood supratentorial neuroglial tumors. The Childhood Brain Tumor Consortium.

Our objective in this study was to identify histologically homogenous classes of childhood supratentorial neuroglial tumors. Previously, we identified five quantitative histologic factors (differing linear combinations of 17 reliably recognized histologic features in neuroglial tumors). They account for much of the histologic variance in the 703 supratentorial tumors in the Childhood Brain Tumor Consortium (CBTC) database. In this study, we used the scores on the factors in cluster analyses and identified eight classes of neuroglial tumors. Each of these classes had significant differences in histology, allowing the separation of many of the conventional types of neuroglial tumors into two or more classes. For instance, fibrillary astrocytoma, pilocytic astrocytoma, subependymal giant cell astrocytoma, anaplastic astrocytoma, oligodendroglioma, and ependymoma were represented in two or more classes. Often these classes had statistically significant differences in survival distributions. For instance, the two classes of "anaplastic astrocytomas" have widely discrepant 5-year survival probabilities of 0.7 and 0.2. Use of the classes identified in this study ensures relatively homogeneous histologic subsets of tumors. We suggest that these classes will be useful for the selection of children for therapeutic clinical trials.

Favorable effect of VEGF gene transfer on ischemic peripheral neuropathy.

Ischemic peripheral neuropathy is a frequent, irreversible complication of lower extremity vascular insufficiency. We investigated whether ischemic peripheral neuropathy could be prevented and/or reversed by gene transfer of an endothelial cell mitogen designed to promote therapeutic angiogenesis. Intramuscular gene transfer of naked DNA encoding vascular endothelial growth factor (VEGF) simultaneously with induction of hindlimb ischemia in rabbits abrogated the substantial decrease in motor and sensory nerve parameters, and nerve function recovered promptly. When gene transfer was administered 10 days after induction of ischemia, nerve function was restored earlier and/or recovered faster than in untreated rabbits. These findings are due in part to enhanced hindlimb perfusion. In addition, however, the demonstration of functional VEGF receptor expression by Schwann cells indicates a direct effect of VEGF on neural integrity as well. These findings thus constitute a new paradigm for the treatment of ischemic peripheral neuropathy.

Limitations of the World Health Organization classification of childhood supratentorial astrocytic tumors. Children Brain Tumor Consortium.

BACKGROUND: In the context of many implied but not rigorously stated histologic feature combinations, the World Health Organization (WHO) classification of astrocytic tumors specifies only the presence or absence of endothelial proliferation, necrosis, and mitosis to distinguish astrocytoma, anaplastic astrocytoma, and glioblastoma multiforme. METHODS: The authors examined the effects of these and other reliably recognized histologic features on survival in the Childhood Brain Tumor Consortium (CBTC) sample of 340 children with supratentorial astrocytic tumors. RESULTS: Overall, the WHO criteria distinguished only two prognostically distinct classes of astrocytomas. When the specific combinations of the three features were unambiguously designated, three diagnostic categories resulted. These revised diagnostic categories are consistent with WHO guidelines and have significantly different survival distributions. However, neither the original WHO diagnoses nor the revised categories adequately separated these tumors prognostically, because histologic features other than those specified by WHO were significantly associated with improved or worsened survival. CONCLUSIONS: Classifications based on small numbers of specified histologic features may not be feasible because they inadequately separate childhood astrocytic tumors into prognostically homogeneous groups. Preferable classification techniques are those that simultaneously account for all reliably recognized histologic features.

Influence of diabetes mellitus on chronic inflammatory demyelinating polyneuropathy.

Patients with diabetes occasionally develop clinical and electrodiagnostic features suggestive of chronic inflammatory demyelinating polyneuropathy (CIDP). To clarify the role of diabetes in patients with a CIDP-like syndrome, we compared the clinical, pathological, and electrodiagnostic features of 14 patients (10 men, 4 women) with diabetes and CIDP (DM-CIDP) to 60 patients with idiopathic CIDP (I-CIDP). The average duration of diabetes was 9 years. The patients with DM-CIDP were older and more often complained of imbalance compared to the idiopathic group, but the frequency of other symptoms and neurologic findings were similar. The mean amplitude of the ulnar compound muscle action potential in the DM-CIDP group was comparatively reduced, the sural sensory nerve action potential was more often absent, and axonal loss was more commonly observed on nerve biopsy. The response rate to treatment was similar, but the magnitude of functional recovery was greater in patients with I-CIDP. Thus, our patients with diabetes and CIDP had clinical features similar to those with idiopathic CIDP, but their nerve conduction studies and nerve biopsies showed more severe axonal loss and the degree of improvement following treatment was less favorable. These differences most likely reflect the additive effects of superimposed diabetic axonal polyneuropathy in patients who develop CIDP.

Chronic motor axonal neuropathy: pathological evidence of inflammatory polyradiculoneuropathy.

Chronic immune and inflammatory motor neuropathies may resemble motor neuron disease, and the distinction may be particularly difficult if conduction block or GM1 antibodies are absent. The pathology of this axonal type of chronic motor neuropathy has not been characterized except in a few cases associated with paraproteinemia. We describe the clinical, electrophysiological, and pathological findings in a patient with a chronic motor axonal neuropathy, normal immunoelectrophoresis, and no GM1 antibodies. At autopsy the spinal cord was normal with the exception of chromatolytic motor neurons. All the ventral roots were greatly thinned. Of 10 mixed nerves and numerous spinal roots sampled, five showed areas of perineurial, perivascular lymphocytic infiltration. There was severe axonal loss in the motor roots that was not as evident in mixed nerves, and the sensory nerves and roots were virtually unaffected. Our findings suggest that a chronic motor axonal neuropathy without paraproteinemia or GM1 antibodies may, in some cases, result from an inflammatory process.

Prognostic limitations of the Daumas-Duport grading scheme in childhood supratentorial astroglial tumors.

The Daumas-Duport grading scheme (DDGS) is a commonly used method for determining the grade of a tumor. It scores 4 histologic features and is used as a prognostic tool in adult astroglial tumors. This system of assigning children to prognostically homogeneous groups has not been evaluated. The Childhood Brain Tumor Consortium (CBTC) database includes 327 children with a CBTC assigned World Health Organization (WHO) diagnosis of supratentorial astroglial tumor and histologic features necessary for Daumas-Duport grading. We compared survival estimates for tumors within and between DDGS grades using a slightly broadened definition of endothelial prominence. The DDGS yielded only 3 histologic groups in children and only 2 prognostically differing groups. Subgroups within DDGS grades had significantly different survival distributions. The summing of 4 disparate histologic features in the DDGS is inadequate for the assessment of childhood supratentorial astroglial tumors. A classification system more fully summarizing the complete histologic content of tumors is most likely to provide diagnoses useful for clinical purposes.

Intracerebral hemorrhage in two patients with Down's syndrome and cerebral amyloid angiopathy.

Cerebral amyloid angiopathy (CAA) is an important cause of spontaneous intracerebral hemorrhages in the elderly and is often seen in the brains of patients with Alzheimer's disease, Down's syndrome (DS), and hereditary cerebral hemorrhage with amyloidosis of the Dutch type. We report two patients with DS and extensive CAA who died of intracerebral hemorrhage; only two other such case reports exist in the literature. We believe the incidence of such cases is higher than is reported and that the likelihood of hemorrhage in the setting of CAA is independent of the patient's underlying disease.

Quantitative histologic factors for grouping childhood infratentorial neuroglial tumors.

We employed factors analysis to quantify the degree of histologic heterogeneity of childhood infratentorial neuroglial tumors. Our data were 26 reliably ascertained histologic features in 1068 children in the Childhood Brain Tumor Consortium database. The factor analysis identified five uncorrelated quantitative "factors," each derived from a different linear combination of the 26 histologic features, that accounted for much of the histologic variation. Histologic features differed in their importance in each factor. The most important features in each factor were used for naming using simple, histologic, familiar descriptive terms: Spongy, Proliferative, Ring, Fibrillary, and Nuclear. Each tumor has a score on each factor. Two-thirds of tumors had high scores for at least two factors, indicating frequent histologic heterogeneity among these tumors. Ninety-five percent of tumors were allocated to 1 of 11 nonoverlapping histologically homogeneous groups. The five quantitative factors complement standard qualitative taxonomies by making explicit the histologic heterogeneity or homogeneity of individual tumors and provide the pathologist with a method that takes advantage of more of the histology of each tumor than conventional nomenclatures. Histologically homogeneous groups of tumors are likely to be of value in clinical trials and biologic research. Prognostic models based on these factors have been published.

Recurrence of medulloblastoma: violation of Collins' law after two decades.

BACKGROUND: Medulloblastoma is a common tumor of childhood arising in the posterior fossa. The concept of a child with an embryonal tumor surviving the age of diagnosis plus 9 months as the period of risk for recurrence (Collins' Law) has been applied to medulloblastomas. This raises the question of "when should follow-up stop for a patient with this type of tumor?" METHODS: We present a case report of a patient with the longest documented exception to Collins' Law for medulloblastoma. RESULTS: The longest documented exception to Collins' Law, a medulloblastoma recurring 20 years and 8 months after the period of risk for recurrence is presented. Both the site of recurrence and the histopathology were identical to the original tumor. CONCLUSION: We present the longest documented exception to Collins' Law, to emphasize that even after decades the term "cure" should only be used cautiously.

New structure, the "olfactory pit," in human olfactory mucosa.

A whole-mount immunocytochemical method was devised to study the olfactory receptor neurons on the surface of the human olfactory mucosal sheet. Antibodies to neuron-specific tubulin and/or microtubule-associated protein 5 and phosphorylated neurofilament protein were used. Specimens taken at autopsy from 56 patients ranging in age from 2 days to 92 years revealed a structure not previously described, an olfactory pit. Round or oval openings with a diameter of 50 to 500 microns were observed on the surface of the olfactory epithelium in the whole-mount specimen. The morphology, number, and distribution of these openings varied among the different individuals. A detailed analysis of these structures was carried out by rehydrating and sectioning the whole-mount specimens. The olfactory pit (OP) is a blind pouch lined with olfactory epithelium (OE), which appears as an invagination of OE into the connective tissue, with a depth varying between 150 and 200 microns. In some sections through an OP, a thick axon bundle emerging from the bottom of the pouch was visible. The extension and termination of this axon bundle in the central nervous system has not been explored. We have found OPs in monkey olfactory mucosa, but none in rodents. The function of the pit specialization is unclear, but it appears to be a feature of normal, young epithelium. The configuration of the blind pouch may prolong odorant association with the olfactory receptor neurons, or the OP may contain specialized neurons that have not yet been recognized by morphological, biochemical, or functional techniques.

Survival of children with infratentorial neuroglial tumors. The Childhood Brain Tumor Consortium.

OBJECTIVE: The goal of this study is the improvement of the prognostic information associated with conventional diagnoses. Our previous factor analysis of 26 reliably identified histological features in infratentorial childhood neuroglial tumors yielded five interpretable, uncorrelated, quantitative histological factors that we named spongy, fibrillary, proliferative, nuclear, and ring. Five quantitative scores, one for each of the five factors, provide an objective method for quantifying the histological heterogeneity of a tumor. The scores, alone or in conjunction with conventional diagnoses, identify groups of histologically homogeneous tumors. METHODS: Multivariate Cox proportional hazards models were developed to assess the contribution of each factor to survival prognosis, after allowing patient-specific demographic and clinical data in the models as covariates. Hazard ratios, estimated for each statistically significant factor and covariate in the multivariate model, provide the basis for the determination of the prognosis. The hazard ratio is the ratio of the hazard function for subjects with an attribute, e.g., an age of 10 years, to the hazard function for subjects who have some chosen baseline attribute, e.g., an age of 1 year. The important criterion of this ratio is beta, a statistic estimated from the survival data in the Childhood Brain Tumor Consortium database of infratentorial neuroglial tumors. Kaplan-Meier survival curves were used to investigate differences in the survival of factor-determined subgroups of patients with various diagnoses. RESULTS: An increased likelihood of survival is associated with older age, more tumor removal, more recent decade of surgical intervention, and high spongy and fibrillary factor scores. A decreased likelihood of survival is associated with high nuclear, proliferative, and ring factor scores. Gender, location within the infratentorial compartment, and subsequent treatment did not add prognostic information. For certain subgroups of astrocytoma and for ependymoma and medulloblastoma, factors are important in predicting survival with greater accuracy. CONCLUSION: Factor scores provide clinically useful quantitative estimates of survival probability that are more specific and accurate than the general estimates based on the conventional diagnosis alone.

Clonal analysis of meningiomas.

Meningiomas are primary brain tumors arising from meningothelial cells. They usually grow slowly and are surgically easy to separate from the brain. A recent clonal analysis of meningiomas, using methylation-sensitive restriction fragment length polymorphisms, suggested a monoclonal origin. Using the same technique but with a highly informative X chromosome probe (M27 beta), we found that 17 (85%) of the 20 meningiomas analyzed were informative. Of the 17 informative tumors, 8 (47%) were monoclonal, 3 (18%) had loss of heterozygosity on the X chromosome, and, unexpectedly, 6 (35%) had a polyclonal pattern. Samples from two areas of one tumor showed a monoclonal pattern and loss of heterozygosity, respectively, on the X chromosome. A review of the histopathological and radiological features of the 17 informative tumors did not help to distinguish the clonal from the polyclonal tumors. We conclude that meningiomas are heterogeneous in clonal composition.

Homolateral hemiparesis as an early sign of cerebellar mass effect.

A patient with Wallenberg's syndrome and an inferior cerebellar infarction developed progressive hemiplegia ipsilateral to the infarction as cerebellar edema emerged. An MRI showed diagonal displacement of the medulla with impaction of the pyramids against the clivus; the hemiplegia resolved after posterior fossa decompression. In the pathologic specimen, the pyramids were flattened and showed small subpial ischemic lesions. Progressive ipsilateral hemiparesis in the setting of cerebellar infarction is an early sign of posterior fossa mass effect similar to the Kernohan's notch phenomenon.

Nerve conduction and biopsy correlation in over 100 consecutive patients with suspected polyneuropathy.

Neuropathy was classified physiologically and histologically as normal, axonal, demyelinative, or indeterminate using specific motor nerve conduction (NC) and sural sensory nerve biopsy (NB) criteria. Physiological and histological diagnoses were concordant in 63%, and minimally discordant in 14% of patients. The most important discordant patients were 6 with demyelinative neuropathy, 4 by NC, of which 2 were pure motor syndromes, and 2 by NB, both predominantly sensory syndromes. In the 55 patients with predominant axonal degeneration on biopsy, the extent of NC slowing was determined. As compound motor and sensory nerve action potential (CMAP and SNAP) amplitude declined, distal motor latency increased, whereas motor and sensory conduction velocity (CV) did not. Minimum F response latency increased as motor CV decreased, more in lower than upper extremity nerves. We conclude that: (1) except for sensory neuropathy, routine motor NC studies generally suffice in identifying demyelinative neuropathy; (2) NC slowing in axonal neuropathy is usually slight but may result in significantly prolonged distal motor latencies when CMAP amplitude is very low, and prolonged F wave latency when motor CV is slightly low; and (3) The physiologic criteria employed in this study rarely misclassifies neuropathy as demyelinative in patients with predominant axon loss on biopsy.

First febrile seizures. Characteristics of the child, the seizure, and the illness.

Through interviews with parents, data were gathered about 910 first febrile seizures in children aged 8 to 34 months. A male preponderance of 57% was found (P < .001). In 29% of cases, there was a family history of febrile seizures. Eighteen percent of seizures were focal, and 7% lasted 15 minutes or more. Focal seizures were much more likely to be of long duration (P < .001). Otitis media was diagnosed in 32% of cases, and tonsillitis or upper respiratory infection in 12%. When compared to febrile seizures after the first birthday, febrile seizures in children aged 8 to 11 months were more than twice as likely to be longer than 15 minutes (P = .015). They were also much more likely to be followed by further seizures in the same illness (P < .001). Thus, febrile seizures in children younger than 1 year are more likely to have the characteristics known to increase the risk of later nonfebrile seizures.