Determinants of exposure to Aedes mosquitoes: A comprehensive geospatial analysis in peri-urban Cambodia

Aedes mosquitoes are some of the most important and globally expansive vectors of disease. Public health efforts are largely focused on prevention of human-vector contact. A range of entomological indices are used to measure risk of disease, though with conflicting results (i.e. larval or adult abundance does not always predict risk of disease). There is a growing interest in the development and use of biomarkers for exposure to mosquito saliva, including for Aedes spp, as a proxy for disease risk. In this study, we conduct a comprehensive geostatistical analysis of exposure to Aedes mosquito bites among a pediatric cohort in a peri‑urban setting endemic to dengue, Zika, and chikungunya viruses. We use demographic, household, and environmental variables (the flooding index (NFI), land type, and proximity to a river) in a Bayesian geostatistical model to predict areas of exposure to Aedes aegypti bites. We found that hotspots of exposure to Ae. aegypti salivary gland extract (SGE) were relatively small (< 500 m and sometimes < 250 m) and stable across the two-year study period. Age was negatively associated with antibody responses to Ae. aegypti SGE. Those living in agricultural settings had lower antibody responses than those living in urban settings, whereas those living near recent surface water accumulation were more likely to have higher antibody responses. Finally, we incorporated measures of larval and adult density in our geostatistical models and found that they did not show associations with antibody responses to Ae. aegypti SGE after controlling for other covariates in the model. Our results indicate that targeted house- or neighborhood-focused interventions may be appropriate for vector control in this setting. Further, demographic and environmental factors more capably predicted exposure to Ae. aegypti mosquitoes than commonly used entomological indices.

Genomic epidemiology of SARS-CoV-2 in Cambodia, January 2020 to February 2021

The first case of coronavirus disease 2019 (COVID-19) in Cambodia was confirmed on 27 January 2020 in a traveller from Wuhan. Cambodia subsequently implemented strict travel restrictions, and although intermittent cases were reported during the first year of the COVID-19 pandemic, no apparent widespread community transmission was detected. Investigating the routes of severe acute respiratory coronavirus 2 (SARS-CoV-2) introduction into the country was critical for evaluating the implementation of public health interventions and assessing the effectiveness of social control measures. Genomic sequencing technologies have enabled rapid detection and monitoring of emerging variants of SARS-CoV-2. Here, we detected 478 confirmed COVID-19 cases in Cambodia between 27 January 2020 and 14 February 2021, 81.3 per cent in imported cases. Among them, fifty-four SARS-CoV-2 genomes were sequenced and analysed along with representative global lineages. Despite the low number of confirmed cases, we found a high diversity of Cambodian viruses that belonged to at least seventeen distinct PANGO lineages. Phylogenetic inference of SARS-CoV-2 revealed that the genetic diversity of Cambodian viruses resulted from multiple independent introductions from diverse regions, predominantly, Eastern Asia, Europe, and Southeast Asia. Most cases were quickly isolated, limiting community spread, although there was an A.23.1 variant cluster in Phnom Penh in November 2020 that resulted in a small-scale local transmission. The overall low incidence of COVID-19 infections suggests that Cambodia's early containment strategies, including travel restrictions, aggressive testing and strict quarantine measures, were effective in preventing large community outbreaks of COVID-19.

1176. Metagenomic Next-Generation Sequencing of Nasopharyngeal Swabs in Acute Febrile Illness in Cambodia

Background

There is growing recognition of metagenomic next-generation sequencing (mNGS) as a valuable diagnostic tool capable of providing unbiased pathogen detection, but data on performance in low-resource settings remains scant. Here, we use mNGS of nasopharyngeal (NP) swabs taken from subjects in Cambodia to identify potential pathogens causing acute febrile illness.

Methods

Febrile subjects aged 2 months to 65 years were enrolled in a cross-sectional study conducted across 4 tertiary hospitals in Cambodia. NP swabs were collected at hospital presentation. Depending on reported symptom constellations, sera was also taken in a subset of subjects for comparison of mNGS results. RNA was isolated from biosamples, converted to cDNA libraries, and sequenced on a NextSeq2000 (Illumina). Raw sequence reads were stripped for host reads and aligned to NCBI nucleotide and protein databases using a cloud-based bioinformatics platform (CZID).

Results

NP swabs were collected from 97 subjects between April 2020 and June 2021. Subjects were predominantly male (53.6%) and young (median age 3 years [IQR 1-25]). Pathogens were identified in 42 (43.2%) NP swabs; of these, 26 (61.9%) were respiratory viruses including 9 rhinovirus, 7 coronavirus (1 SARS-CoV-2), and 5 respirovirus cases. Co-infection was identified in 3 subjects with coronavirus and respirovirus (N=2) and coronavirus and rhinovirus (N=1). Of subjects with paired sera and NP samples (N=61), 18 (29.5%) had positive NP swabs but negative sera, 7 (11.5%) had negative NP swabs but positive sera, 12 (19.7%) had positive NP swabs and sera, and 24 (39.3%) had negative NP swabs and sera. Pathogen hits correlated in NP swabs and sera in 10 of 12 subjects, including six subjects with chikungunya.

Conclusion

mNGS can be successfully implemented in low-resource settings to identify emerging pathogens and common respiratory pathogens, including co-infecting pathogens, from NP swabs of febrile patients. mNGS may also be able to detect chikungunya from NP swab alone, raising the possibility of non-invasive diagnostics for infections associated with high viremic states.

Disclosures

All Authors: No reported disclosures.

SARS-CoV-2 Cross-Reactivity in Prepandemic Serum from Rural Malaria-Infected Persons, Cambodia

Inhabitants of the Greater Mekong Subregion in Cambodia are exposed to pathogens that might influence serologic cross-reactivity with severe acute respiratory syndrome coronavirus 2. A prepandemic serosurvey of 528 malaria-infected persons demonstrated higher-than-expected positivity of nonneutralizing IgG to spike and receptor-binding domain antigens. These findings could affect interpretation of large-scale serosurveys.

Pre-pandemic SARS-CoV-2 serological reactivity in rural malaria-experienced Cambodians

Greater Mekong inhabitants are exposed to pathogens, zoonotic and otherwise, that may influence SARS-CoV-2 seroreactivity. A pre-pandemic (2005 to 2011) serosurvey of from 528 malaria-experienced Cambodians demonstrated higher-than-expected (up to 13.8 %) positivity of non-neutralizing IgG to SARS-CoV-2 spike and RBD antigens. These findings have implications for interpreting large-scale serosurveys.

ARTICLE SUMMARY LINE

In the pre-COVID19 pandemic years of 2005 to 2011, malaria experienced Cambodians from rural settings had higher-than-expected seroreactivity to SARS-CoV-2 spike and receptor binding domain proteins.

Macrophages as IL-25/IL-33-responsive cells play an important role in the induction of type 2 immunity

Type 2 immunity is essential for host protection against nematode infection but is detrimental in allergic inflammation or asthma. There is a major research focus on the effector molecules and specific cell types involved in the initiation of type 2 immunity. Recent work has implicated an important role of epithelial-derived cytokines, IL-25 and IL-33, acting on innate immune cells that are believed to be the initial sources of type 2 cytokines IL-4/IL-5/IL-13. The identities of the cell types that mediate the effects of IL-25/IL-33, however, remain to be fully elucidated. In the present study, we demonstrate that macrophages as IL-25/IL-33-responsive cells play an important role in inducing type 2 immunity using both in vitro and in vivo approaches. Macrophages produced type 2 cytokines IL-5 and IL-13 in response to the stimulation of IL-25/IL-33 in vitro, or were the IL-13-producing cells in mice administrated with exogenous IL-33 or infected with Heligmosomoides bakeri. In addition, IL-33 induced alternative activation of macrophages primarily through autocrine IL-13 activating the IL-4Rα-STAT6 pathway. Moreover, depletion of macrophages attenuated the IL-25/IL-33-induced type 2 immunity in mice, while adoptive transfer of IL-33-activated macrophages into mice with a chronic Heligmosomoides bakeri infection induced worm expulsion accompanied by a potent type 2 protective immune response. Thus, macrophages represent a unique population of the innate immune cells pivotal to type 2 immunity and a potential therapeutic target in controlling type 2 immunity-mediated inflammatory pathologies.

A new type of leukoencephalopathy with metaphyseal chondrodysplasia maps to Xq25-q27

BACKGROUND

The authors report a three-generation family with four male patients presenting with a novel type of X-chromosomal leukoencephalopathy associated with skeletal abnormalities.

METHODS

The index patient and his brother reached their early motor milestones in due time and had normal language development. Between the ages of 2 and 3 years, first signs of spastic paraplegia were noticed. Furthermore, the patients developed tremor, ataxia, optic atrophy, and spastic tetraparesis. Both boys had broad wrists and knees without significant contractures. A maternal uncle and a granduncle had the same disease.

RESULTS

Leukoencephalopathy (MRI, MRS) and metaphyseal chondrodysplasia (X-ray, MRI) were diagnosed. MRS showed a reduction of choline-containing compounds in the white matter. An autopsy on one of the patients, who died at age 37 years, revealed an orthochromatic type of leukoencephalopathy. In bone and cartilage tissue, unspecific signs of a mild chondrodysplasia were found. At the PLP gene locus an obligate recombination was observed, which excludes the Pelizaeus-Merzbacher locus on Xq21-22. However, affected males share a fragment of the long arm of chromosome X.

CONCLUSION

The authors report a new type of leukoencephalopathy associated with metaphyseal chondrodysplasia located on Xq25-q27.

Contribution of diffusion tensor imaging to delineation of gliomas and glioblastomas

PURPOSE

To determine if the diffusion tensor imaging (DTI) parameters fractional anisotropy (FA) and mean diffusivity (MD) can differentiate between accompanying edema and tumor cell infiltration of white matter (WM) beyond the tumor edge as defined from conventional MRI in low- and high-grade gliomas.

MATERIALS AND METHODS

We examined 12 patients with high-grade gliomas/glioblastomas and eight patients with low-grade gliomas and compared them to 10 patients with meningiomas, in which no tumor infiltration is expected. The tumor was defined as the enhancing area in glioblastomas and meningiomas and as the area of increased T2-signal in low-grade gliomas. FA and MD were measured in the center of the tumor and in the adjacent WM. The contralateral WM and internal capsule were used as an internal standard.

RESULTS

Comparing the WM areas of increased T2-signal adjacent to meningiomas and glioblastomas, we saw a trend (without significance) towards a reduction of FA, but not of MD, in glioblastomas. We found no changes of FA and MD in the WM adjacent to low-grade gliomas (without T2-signal increase) compared to the WM of the contralateral hemisphere. In meningiomas and high-grade gliomas/glioblastomas, a narrow rim of significantly (P < 0.01) increased FA and decreased MD values around the enhancing tumor area was seen, whereas in low-grade gliomas, such a rim could not be defined. There was no contribution of FA or MD to grading of gliomas.

CONCLUSION

In glioblastomas, a reduction of FA in the edematous area surrounding the tumor may indicate tumor cell infiltration, but a reliable differentiation between infiltration and vasogenic edema is not yet possible on the basis of DTI. The additional finding of a narrow rim of increased FA and decreased MD at the edge of glioblastomas (as well as in meningiomas) may be caused by com-pressed WM fibers and/or increased vascularity, but does not contribute to exclude peripheral cellular infiltration.

Extended pathoanatomical studies point to a consistent affection of the thalamus in spinocerebellar ataxia type 2

The involvement of the thalamus during the course of the currently known polyglutamine diseases is still a matter of debate. While it is well-known that this diencephalic nuclear complex undergoes neurodegeneration in some polyglutamine diseases such as Huntington's disease (HD), it has remained unclear whether and to what extent the thalamus is also involved in spinocerebellar ataxia type 2 (SCA2) patients. Encouraged by our recent post-mortem findings in one German SCA2 patient and the results of a recent nuclear magnetic resonance (NMR) study, we extended our pathoanatomical analysis to serial thick sections stained for lipofuscin granules and Nissl substance through the thalami of four additional German and Cuban SCA2 patients. According to this analysis the thalamus is consistently affected by the destructive process of SCA2. In particular, during our study we observed a consistent involvement of the lateral geniculate body, the lateral posterior, ventral anterior, ventral lateral, ventral posterior lateral, and ventral posterior medial thalamic nuclei as well as the extraterritorial reticular nucleus. In four of the SCA2 cases studied additional damage was seen in the inferior and lateral nuclei of the pulvinar, whereas in the minority of the patients a subset of the limbic nuclei of the thalamus (i.e. anterodorsal, anteroprincipal, laterodorsal, fasciculosus, mediodorsal, central lateral, central medial, cucullar, and paracentral nuclei, medial nucleus of the pulvinar) underwent neurodegeneration. These interindividual differences in the distribution pattern of thalamic neurodegeneration indicate that the thalamic nuclei differ in their proclivities to degenerate in SCA2 and may suggest that they become involved at different phases in the evolution of the underlying degenerative process.

Spinocerebellar ataxias types 2 and 3: degeneration of the pre-cerebellar nuclei isolates the three phylogenetically defined regions of the cerebellum

The pre-cerebellar nuclei act as a gate for the entire neocortical, brainstem and spinal cord afferent input destined for the cerebellum. Since no pathoanatomical studies of these nuclei had yet been performed in spinocerebellar ataxia type 2 (SCA2) or type 3 (SCA3), we carried out a detailed postmortem study of the pre-cerebellar nuclei in six SCA2 and seven SCA3 patients in order to further characterize the extent of brainstem degeneration in these ataxic disorders. By means of unconventionally thick serial sections through the brainstem stained for lipofuscin pigment and Nissl material, we could show that all of the pre-cerebellar nuclei (red, pontine, arcuate, prepositus hypoglossal, superior vestibular, lateral vestibular, medial vestibular, interstitial vestibular, spinal vestibular, vermiform, lateral reticular, external cuneate, subventricular, paramedian reticular, intercalate, interfascicular hypoglossal, and conterminal nuclei, pontobulbar body, reticulotegmental nucleus of the pons, inferior olive, and nucleus of Roller) are among the targets of both of the degenerative processes underlying SCA2 and SCA3. These novel findings are in contrast to the current neuropathological literature, which assumes that only a subset of pre-cerebellar nuclei in SCA2 and SCA3 may undergo neurodegeneration. Widespread damage to the pre-cerebellar nuclei separates all three phylogenetically and functionally defined regions of the cerebellum, impairs their physiological functions and thus explains the occurrence of gait, stance, limb and truncal ataxia, dysarthria, truncal and postural instability with disequilibrium, impairments of the vestibulo-ocular reaction and optokinetic nystagmus, slowed and saccadic smooth pursuits, dysmetrical horizontal saccades, and gaze-evoked nystagmus during SCA2 and SCA3.

Flow-cytometric DNA analysis of intracranial tumors in children

The objective of this study was to investigate flow-cytometric DNA values of pediatric intracranial tumors, and to establish DNA analysis as a potential prognostic parameter. Twenty-nine brain tumor specimens from 26 pediatric patients were cryo-preserved within a 3-year period. The DNA content was measured by flow cytometry. Six of the tumor specimens had aneuploid DNA patterns. The median of the proliferation index was lower in the survivor group compared with the non-survivor group (36.4% and 47.5%, respectively). Ten of the 26 patients are still alive, eight were lost to follow up, and eight died. Flow-cytometric DNA analysis may be a helpful tool for examining brain tumors in children. The small size of this study could not establish flow cytometry as a definite prognostic factor, but further prospective multicenter studies will evaluate the prognostic significance of flow-cytometric DNA analysis.

Colocalization of different types of amyloid in the walls of cerebral blood vessels of patients suffering from cerebral amyloid angiopathy and spontaneous intracranial hemorrhage: a report of 5 cases

Four cases of spontaneous intracranial hemorrhage (ICH) are described in which the diagnosis of a cerebral amyloid angiopathy (CAA) was made in the biopsy specimens. In one further case CAA was detected on autopsy after intracranial hemorrhage (ICH). Amyloidotic degeneration of the vessel walls appeared to be the most likely reason for the ICH which in these cases especially involved superficial neocortical regions. In all cases, co-deposition of A4beta-amyloid and ALlambda-amyloid was found in diseased leptomeningeal and cortical vessels. Besides CAA, all 5 patients suffered from other diseases which had affected the blood vessel walls such as atherosclerosis, diabetes mellitus or arterial hypertension. However, no signs of systemic amyloidosis could be detected in these cases. It is suggested that the observed co-deposition of 2 amyloid subtypes is based on the combination of 2 different diseases, one of which results in a local production of A4beta-amyloid in the tunica media of cerebral blood vessels and another one, e.g. arterial hypertension, which impairs the permeability of the blood vessels by affection of the tunica intima allowing for the pathological penetration of circulating immunoglobulin lambda-light chains into the vessel wall. Subsequently, the preexisting A4beta-amyloid might have induced the polymerization of the lambda-light chains to ALlambda-amyloid in the media of the vessels and could have aggravated the amyloidotic degeneration of the vessel walls.

Organisation and maturation of the human thalamus as revealed by CD15

The distribution of the CD15 antigen (CD15, 3-fucosyl-N-acetyl-lactosamine, Lewis x) has been studied immunohistochemically in the fetal human thalamus. Its changing patterns could be related to three successive, but overlapping, periods primarily due to its association with radial glial cells, neuropil, and neural cell bodies, respectively. From 9 weeks of gestation (wg), a subset of CD15-positive radial glial cells distinguished the neuroepithelium of the ventral thalamus, a characteristic also seen in the developing mouse. Distal processes of the radial glial cells converged at the root of the forebrain choroid tenia, which was also CD15 positive. From 13 wg until approximately 20 wg, CD15-positive neuropil labeling marked the differentiation areas of prospective nuclei within the dorsal thalamus and progressively outlined their territories in a time sequence, which appeared specific for each nucleus. CD15 labeling of differentiating nuclei of the ventral, medial, anterior, and intralaminar thalamic divisions showed a transient topographic relationship with restricted areas of the ventricular wall. After 26 wg, CD15 immunoreactivity was observed in subpopulations of glial cells and neurons. Transient CD15 immunoreactivity was also found in delimited compartments within the subventricular region. The time of CD15 expression, its location, and cellular association suggest that CD15 is involved in segmentation of diencephalon, in the specification of differentiating nuclear areas and initial processes regarding the formation of intercellular contacts and cellular maturation.

[Bilateral progressive hearing loss as the first manifestation of metastatic carcinoma of the head of the pancreas. Case report]

We report the history of a patient who presented first with a progressive unilateral hearing loss and later with a bilateral deafness and an unilateral facial nerve palsy as first and only symptoms of a pancreatic adenocarcinoma. By means of magnetic resonance tomography tumor-suspect lesions in both internal auditory canals were detected. Referring to the results of further examinations these intracanalicular lesions are most probably due to rarely seen bilateral metastasis of a pancreatic adenocarcinoma in the temporal bone. In addition to this rarely diagnosed localisation of metastasis it is rather uncommon that this kind of primary malignoma had not been detected because of gastrointestinal symptoms or extracranial metastasis.

Development-related expression of AKAP79 in the striatal compartments of the human brain

The expression of AKAP79 which tethers regulatory proteins within postsynaptic densities has been studied in the two striatal compartments, i.e. patches and matrix, at different stages of the developing human brain by means of immunohistochemistry. The two striatal compartments exhibit various intensities of diffuse immunolabelling and a different number of immunoreactive nerve cells. From the 14th to 20th gestational week a nearly homogeneous distribution of immunoreactive structures in the two compartments of the striatum is seen. Thereafter, a decrease in immunoreactive structures within the matrix is observed (22nd-25th week, intermediate stage). From the 27th week onwards the patch compartment contains distinctly more immunoreactive puncta and nerve cells. Thus, the patches stand out clearly in the immunopreparations. This distribution pattern does not change during proceeding development. AKAP79-immunoreactive nerve cells closely resemble those constituting the class of medium-sized inhibitory projection neurons that receive the dopaminergic input of the striatum. Literature data suggest that AKAP79 may be functionally attributed to dopaminergic inputs. Accordingly, the patterns of AKAP79 expression can at least in part be correlated with the sequential occurrence of dopaminergic innervation. The mature matrix containing a dopaminergic innervation being as dense as in the patches displays distinctly less AKAP79-immunoreactive neurons and puncta than the patches. This discrepancy might indicate that a subpopulation of matrix neurons may, despite dopaminergic input, not express AKAP79.

[Fatal outcome during physiotherapy (Vojta's method) in a 3-month old infant. Case report and comments on manual therapy in children]

Detailed clinical and neuropathological report on a fatal incident during the first manual therapy according to Vojta conducted in a 3 months old baby: during forced active rotation and head retraction the baby suffered from a bleeding into the adventitia of both her vertebral arteries at the level of C1 prompting ischemia of the caudal brainstem with subarachnoid haemorrhage around. It has to be suggested that similar cases already have occurred but have not been reported yet. There might be a time lag between the performance of physiotherapy and the beginning of neurologic symptoms. The risks of manual therapy in children will be discussed.

Neurodegenerative diseases

This article briefly discusses and illustrates the major important neurodegenerative diseases of adulthood and neurometabolic (neurodegenerative in a broader sense) diseases of childhood and their gross neuropathology. Macroscopic views of the brain including the cerebellum and the brain stem and the spinal cord are given by external inspection as well as gross sections after brain cutting. Histologic details and photographs are supplied to explain and corroborate certain gross findings. This article attempts to correlate nosologic and neuropathologic features as the basis for interpreting neuroimaging data.

Cooperative transformation and coexpression of bovine papillomavirus type 1 E5 and E7 proteins

Productively infected bovine fibropapillomas were examined for bovine papillomavirus type 1 (BPV-1) E7 localization. BPV-1 E7 was observed in the cytoplasm of basal and lower spinous epithelial cells, coexpressed in the cytoplasm of basal cells with the E5 oncoprotein. E7 was also observed in nucleoli throughout the basal and spinous layers but not in the granular cell layer. Ectopic expression of E7 in cultured epithelial cells gave rise to localization similar to that seen in productive fibropapillomas, with cytoplasmic and nucleolar expression observed. Consistent with the coexpression of E7 and E5 in basal keratinocytes, BPV-1 E7 cooperated with E5 as well as E6 in an anchorage independence transformation assay. While E5 is expressed in both basal and superficial differentiating keratinocytes, BPV-1 E7 is only observed in basal and lower spinous epithelial cells. Therefore, BPV-1 E7 may serve to modulate the cellular response of basal epithelial cells to E5 expression.

Effect of fetal hydrocephalus on the distribution patterns of calcium-binding proteins in the human occipital cortex

Neuronal pathology in the cerebral cortex (CC) of fetal hydrocephalus brains is quite subtle when applying routine Nissl staining. This study is aimed at investigating alterations of interneurons which can be immunolabelled by antibodies against the calcium-binding proteins calretinin (CR), calbindin (CB) and parvalbumin (PV). The subplate (SP) subjacent to the cortex anlage is included as this transient zone plays a pivotal role in the establishment of cortical connections. Nine occipital lobes from cases of fetal hydrocephalus and 9 controls were categorized according to age: 21-25 weeks of gestation (group 1) and 32-36 weeks (group 2). No differences in the distribution, number and morphology of CR-immunoreactive (ir) neurons are seen when comparing hydrocephalic with control brains of group 1. In severely altered hydrocephalic brains of group 2, the distribution and number of CR-, PV- and CB-ir nerve cells are not altered; however, they appear shrunken and processes are less immunolabelled. In extremely altered tissue PV-, CB-ir neurons cannot be detected, whereas the number of CR-ir somata is not reduced. The data indicate that subpopulations of interneurons of the CC may be differentially damaged. The alterations observed in the SP may implicate a possible impairment of transient neuronal circuitries that are essential for the development of cortical connections. On the whole, these neuronal alterations may account for residual deficits observed after shunting.

Expression of MAP1a and MAP1b in the ganglionic eminence and the internal capsule of the human fetal brain

The expression of microtubule-associated proteins 1a and 1b (MAP1a and 1b) were investigated in two transient structures, the ganglionic eminence (GE) being a prominent part of the telencephalic proliferative zone and the perireticular nucleus (PR) within the internal capsule (IC). Anti-MAP1a immunolabels PR neurons from 18 weeks of gestation (wg) onwards, whereas anti-MAP1b immunolabels long IC fibers between 18 and 22 wg. MAP1b is further present in thalamic fibers that seem to terminate at the medial margin of the GE, in a moderate number of cells of the GE and its medial extension, the gangliothalamic body (GTB). From 26 to 33 wg MAP1b is expressed in short fiber bundles of the IC, a few MAP1b-positive cells are seen in the GE. MAP1a has so far been described to appear in differentiated neurons and to be related to late developmental events. However, the transient PR being involved in axonal guidance as an intermediate target shows a precocious MAP1a-expression. The MAP1b-finding that thalamocortical fibers accumulate at the GE-margin indicates that this region represents an intermediate target for these fibers. The short MAP1b fiber bundles found in the IC are in accordance with cell culture experiments showing that MAP1b is concentrated in distal parts of outgrowing axons.

Transient expression of synaptogyrin in the ganglionic eminence of the human fetal brain

The ganglionic eminence (GE) representing a conspicuous bulb-like elevation of the telencephalic proliferative zone has recently been shown to be involved in the establishment of cortical connections. This study demonstrates the presence of synaptogyrin-immunoreactivity in a large number of cell bodies of the human GE between 12 and 20 weeks of gestation. From the 20th week onwards synaptogyrin expression sharply declines. No immunoreactive structures are detectable in the 23rd week or later. As the GE persists nearly throughout the entire fetal period these results show that its neurochemical features change distinctly in the course of development. The synaptogyrin-immunoreactive GE-cells may form an early corticopedal connection which provides a scaffold for outgrowing cortical axons.

Transient architectonic features in the basolateral amygdala of the human fetal brain

The architectonical differentiation in the basolateral nuclei of the human fetal amygdala - with special reference to transient structures - was studied using series of relatively thick Nissl-stained sections. These architectonic features were correlated with the process of migration. Radial glial fibers providing the scaffold of migratory routes can reliably be marked with the aid of antivimentin. In the 5th gestational month a transient feature is conspicuous in the inferior portions of the basolateral nuclei bordering upon the ganglionic eminence (proliferative zone): columnar cell clusters, separated by cell-sparse septa, extend from the poliferative zone to the nuclei. The width of the cell columns vary considerably between the different nuclei. In vimentin immunopreparations fibers are found inside these cell columns. So they most probably reflect clustered migratory streams. Two months later, instead of this merging area between the ganglionic eminence and the amygdaloid nuclei a cell-free capsule envelopes the nuclei and clearly separates them from the ganglionic eminence. Changes in cytoarchitectonics are accompanied by a distinct rearrangement of radial glial fibers. A basket-like arrangement of the vimentin-immunoreactive fibers around the cell columns inside the cell sparse septa is found. Towards the end of pregnancy radial glial fibers gradually vanish. A comparison of Nissl and vimentin preparations reveals that transient architectonic characteristics as visible in relatively thick Nissl sections may be correlated with migrational routes.

Transient structures of the human fetal brain: subplate, thalamic reticular complex, ganglionic eminence

Morphological features of the subplate, the thalamic reticular complex and the ganglionic eminence, which represent three major transient structures of the human fetal forebrain, are summarized with special reference to their functional roles. The subplate harboring various neuronal types is an outstandingly wide zone subjacent to the cortical plate in the human fetal brain. Within the subplate various cortical afferents establish synaptic contacts for a prolonged period before entering the cortical plate. Therefore, the subplate is regarded as a "waiting compartment" which is required for the formation of mature cortical connections. Next to the thalamic reticular nucleus, within the fibers of internal capsule, the perireticular nucleus is located which has been established as a distinct entity during development. Its various neuronal types express a number of different neuroactive substances. Perinatally, the perireticular nucleus is drastically reduced in size. It is involved in the guidance of corticofugal and thalamocortical fibers. The ganglionic eminence is a conspicuous proliferative area that persists throughout nearly the entire fetal period. In the human fetal brain it extends medially upon the dorsal thalamic nuclei which receive precursor cells from the ganglionic eminence. Postmitotic cells in the marginal zone of the ganglionic eminence serve as an intermediate target for growing axons. On the whole, all three structures establish transient neural circuitries that may be essential for the formation of adult projections. The characteristics of the three transient structures are particularly relevant for developmental neuropathology as these structures may be damaged in disorders that preferentially occur in preterm infants.

Pathological changes in the parahippocampal region in select non-Alzheimer's dementias

The transentorhinal and entorhinal regions of the human brain extend over the ambient gyrus and anterior portions of the parahippocampal gyrus. They are important components of the limbic loop which receives its major afferents from the neocortical sensory association areas and generates powerful efferent projections both directly and via intermediary relay stations to the prefrontal cortex. The bilateral structural preservation of limbic loop components is a prerequisite for the maintenance of intact memory functions. In progressive neurodegenerative diseases, such as Alzheimer's disease, argyrophilic grain disease, Pick's disease, idiopathic Parkinson syndrome, and Huntington's disease, the transentorhinal and entorhinal regions are particularly susceptible to severe pathological changes. The transentorhinal region typically registers the initial alterations and becomes the most severely involved. From this transitional region of the mesocortex, the alterations usually invade with decreasing severity both the entorhinal region and temporal proneocortex. Each type of lesion that develops in the above-mentioned neurodegenerative disorders hampers or even interrupts data-transport from the sensory neocortex to the prefrontal neocortex, thereby contributing to the insidious development of progressive changes in personality, cognitive decline, and, ultimately, dementia.

Competitive binding to a charged leucine motif represses transformation by a papillomavirus E6 oncoprotein

E6 oncoproteins from HPV-16 and bovine papillomavirus type 1 (BPV-1) bind to similar leucine-rich peptides termed charged leucine motifs found on the cellular focal adhesion protein paxillin and the E3 ubiquitin ligase E6AP. BPV-1 E6 (BE6) mutants that do not bind to paxillin are defective at inducing cellular transformation. It is possible, however, that BE6 mutants that do not bind paxillin are defective for transformation for an unrelated reason than the ability to bind to charged leucine motifs. To address the role of BE6 interaction with charged leucine motifs, we fused a BE6-binding charged leucine motif to the amino terminus of BE6, thereby creating an autoinhibitory binding domain. We found that the fusion protein failed to bind to paxillin or transform murine C127 cells. Mutation of the amino terminal binding motif in the fusion protein restored both interaction with paxillin and transformation. This demonstrates that BE6 transformation requires binding to charged leucine motifs on particular cellular proteins and that transformation by papillomavirus oncoproteins can be repressed by competitive interactions with charged leucine motifs.

Distribution of SNAP-25 in transient neuronal circuitries of the developing human forebrain

The distribution of SNAP-25 is demonstrated within prominent transient structures in the developing human forebrain. During early fetal development SNAP-25 is mainly expressed in axons of the intermediate zone and the internal capsule. The fibers appear directed towards the mantle zone of the ganglionic eminence and the perireticular nucleus located within the internal capsule. Cells of these two areas are shown to interact with SNAP-25 immunoreactive structures with the aid of double-labellings. The SNAP-25 immunoreactive fibers may represent corticofugal axons which contact the perireticular nucleus and ganglionic eminence which are regarded as intermediate targets providing a scaffold for growing axons. Anti-SNAP-25, thus, is an appropriate marker of intermediate targets which are involved in brain injuries of preterm infants.

Neuropathology of Alzheimer's disease: what is new since A. Alzheimer?

Alzheimer's disease results from severe cytoskeletal alterations in only a few neuronal types within the human central nervous system. These intraneuronal changes take the form of neurofibrillary tangles and neuropil threads. Beginning in predisposed induction sites in the allocortex, the lesions follow a predictable sequence as they engulf other territories of the cerebral cortex and a specific set of subcortical nuclei. Some components of the brain are devastated, while others remain intact until the end phase of the disease. Assessment of the location of the afflicted neurons and the severity of the lesions allows the distinction of stages in the development of the disease. The degenerative process begins with the emergence of the first lesions, at whatever age it occurs. The illness remains subclinical for years, and proceeds inexorably, gradually laying waste to higher order limbic system centers. Clinical symptoms are observed only late in the course of the disease, and their appearance is usually concurrent with the encroachment of the destructive process upon neocortical association areas. The sequence of destruction bears a striking resemblance to the inverse sequence of cortical myelination. Late myelinating areas and layers develop the disease-related changes earlier and at higher densities than those which are myelinated early. The brain of the human adult is heavily laden with intraneuronal deposits of lipofuscin and neuromelanin pigment. The average density of neuronal pigmentation in given cortical areas mirrors the density of cytoskeletal lesions that develop in the course of the disease. Pigment-laden neuronal types giving rise to a single long, thin, unmyelinated or sparsely myelinated axon are particularly prone to developing Alzheimer's disease-related cytoskeletal changes.

Identification of a second transforming function in bovine papillomavirus type 1 E6 and the role of E6 interactions with paxillin, E6BP, and E6AP

Papillomavirus E6 oncoproteins transform mammalian cells through interaction with cellular proteins. Bovine papillomavirus type 1 E6 (BE6) interacts with three previously described cellular targets: the E6AP E3 ubiquitin ligase, the calcium-binding protein E6BP (also known as ERC-55), and paxillin, which is a focal adhesion adapter protein. BE6 interacts strongly with each of these proteins in vitro, binding to similar peptide sequences found in E6AP, E6BP, and paxillin. To determine which BE6 interactions are necessary for transformation by BE6, we used a novel selection strategy for temperature-sensitive BE6 mutants in yeast that could discriminate in their interaction between E6AP, E6BP, and paxillin. All BE6 mutants that retained transforming ability retained association with paxillin, while some mutants that were transformation positive failed to interact with E6AP or E6BP. This study demonstrates that oncogene mutants that are temperature sensitive for transformation can be selected in yeast and that the induction of anchorage-independent cell proliferation by BE6 does not require strong association of BE6 with either E6AP or E6BP. Of particular interest is the identification of a BE6 mutant that interacts strongly with the acidic charged leucine motifs of E6AP, E6BP, and paxillin but is devoid of transformation activity, thereby genetically identifying a second essential transformation function in BE6 that is independent of interaction with acidic charged leucine motifs.

[Clinical aspects of "argyrophilic grain disease"]

Argyrophilic grain disease (AGD) is a frequently occurring degenerative illness of the aging human brain. It is accompanied by progressive pathological alterations of the cytsokeleton which are traceable to an abnormal phosphorylation of the microtubule associated tau protein. Histologically, it is possible with the help of suitable staining techniques to identify pathognomonic spindle-shaped cellular inclusions (argyrophilic grains). These cellular inclusions display a typical cortical as well as subcortical distribution pattern. The goal of the present study is the retrospective evaluation of the clinical findings from 53 individuals with neuropathologically demonstrable AGD-related changes of the brain. Nearly one-half of the cases (49%) was classifiable as demented in accordance with DSM IV-criteria. Moreover, the frequency of the dementia increased significantly in relation to the growing severity of the AGD-associated pathological cytoskeletal degeneration. These results confirm the assumption that AGD can cause degenerative changes ranging from cognitive impairment all the way to dementia. They also underscore the necessity of further prospective studies pertaining to the clinical aspects of this still enigmatic disease.

Apolipoprotein E isoforms and the development of low and high Braak stages of Alzheimer's disease-related lesions

In recent research, apolipoprotein-E (apoE) polymorphism has been shown to influence the formation of neurofibrillary changes and the accumulation of beta/A4-amyloid, the histopathological hallmarks of Alzheimer's disease (AD). Clinical studies associate the apoE allele epsilon4 with earlier onset of the disease, although the clinical speed of progression remains unchanged. Time course estimates have also provided evidence which indicates that the clinical phase of AD constitutes only 10-20% of the total time span needed for the development of this slowly progressing degenerative brain disorder. Due to the lack of reliable clinical tests for the detection of pre-symptomatic stages of AD, we set out with an autopsy approach to monitor neuropathology of the long pre-clinical phase of AD. This study examined beta/A4-peptide deposition and the formation of neurofibrillary changes staged according to the Braaks' classification in groups of individuals matched for age and sex with different genotypes. In comparison with epsilon3 homozygotes, the presence of the epsilon4 allele is statistically associated with a higher stage of beta/A4-peptide deposition and neurofibrillary change formation (chi2-test, P<0.01 for beta/A4-stage and P<0.001 for neurofibrillary changes). The effect of the epsilon2 allele differs. Its presence is associated with a lower stage of neurofibrillary pathology in individuals below the age of 80 but with a higher stage thereafter compared to age- and sex-matched epsilon3 homozygotes. Accordingly, the statistical juxtaposition of individuals over 80 years with epsilon4 alleles and those with epsilon2 alleles showed no significant difference with respect to the stages. Our findings indicate that apoE-variants have different effects on the speed of histopathology formation, even in the pre-clinical stages of AD. This suggests that clinical onset, course and pathogenesis of AD are influenced by the apoE genotype.

Leptomeningeal carcinomatosis and cranial nerve palsy as presenting symptoms of a clinically inapparent gallbladder carcinoma

We present an occult metastatic signet-ring cell gallbladder carcinoma in a 78-year-old woman, who complained of recurrent headaches, dysarthria, and paresis of the tongue. Cranial imaging showed contrast enhancement of the basal leptomeninges, and the cerebrospinal fluid displayed clusters of adenocarcinoma cells proposed as leptomeningeal carcinomatosis of the breast, lung or gut. However, postmortem examination revealed the gallbladder as the site of the primary carcinoma with focal signet-ring cell differentiation. In patients with progressive neurologic deterioration due to leptomeningeal carcinomatosis, adenocarcinomas from the gastrointestinal and hepatic systems should be considered. It is likely that signet-ring cell carcinomas display an increased affinity to leptomeningeal spread.

Distribution patterns of vimentin-immunoreactive structures in the human prosencephalon during the second half of gestation

Neuronal migration is guided by long radially oriented glial fibres. During late stages of development radial glial cells are transformed into astrocytes. A predominant intermediate filament protein within radial glial cells and immature astrocytes is vimentin. In this study fetal brain sections were used to demonstrate the transient features of vimentin-positive radial glia. In the lower half of the cerebral wall of the 6th gestational month bundles, curvature, and crossing of vimentin-positive fibres are regularly seen. Moreover, fibres terminating on vessels are observed. In the upper half fibres are radially oriented; when ascending towards the pial surface the number and diameter of fibres appears conspicuously decreased. Radially aligned fibres display numerous varicosities. In the 8th month the bulk of vimentin-positive fibres is encountered next to the ganglionic eminence and below isocortical cerebral fissures. The dentate gyrus is conspicuous due to its high amount of immunolabelled fibres. Furthermore, densely packed fibres are visible within the internal and external capsule and in the vicinity of the anterior commissure. Radial glial somata are found in the proliferative areas as well as in the adjacent white matter. In the latter location bipolar, monopolar and stellate vimentin-positive cells are present. The results demonstrate an area-specific distribution pattern of vimentin-positive structures which can be correlated with migrational events. Areas maturing late in development for instance, reveal dense immunolabelling in the 8th month. The orientation and position of radial fibres point to an additional developmental role of these fibres, i.e. their involvement in the guidance of growing axons. Moreover, the arrangement and morphology of vimentin-positive fibres, such as retraction of fibres or occurrence of varicosities, are indicative of degenerative events. Accordingly, a transformation of radial glial somata, their displacement towards the white matter and finally the growth of stellate processes can clearly be demonstrated.

Psychic stress as a trigger of the spontaneous development and rupture of an aneurysm? A case report

SUMMARY

We present angiographical and neuropathological data of a 51-year-old woman, who primarily suffered from a recurrent glomus temporale tumour on the left side and who finally died after a spontaneous rupture of a distal basilar aneurysm which developed during angiography. As a second important finding the existence of a vasospasm at the time of the rupture is also confirmed.

Distribution of GAP-43-immunoreactive structures in the human fetal amygdala

The growth-associated protein GAP-43 is a developmentally regulated protein which is involved in the formation of neuronal contacts. In immunohistochemical studies, GAP-43 is detected within axons during their elongation; thus a fibrous immunoreactivity is visible. After axonal growth is completed there is a shift from a fibrous to a punctate immunoreactivity. The latter has been shown to correlate with synaptogenesis. In the amygdala of the 5th gestational month, a fibrous GAP-43-immunoreactivity is seen in the basolateral nuclei, whereas the corticomedial nuclei exclusively show a punctate immunoreactivity. In the 7th month, all amygdaloid nuclei display immunoreactive puncta, but no fibers. In the 9th month GAP-43-immunoreactivity is no longer visible within the amygdala. The results demonstrate the differential distribution of GAP-43-immunoreactive structures in the amygdaloid nuclei. The nuclear specific immunostaining and its changes may indicate the sequential appearance of the monoaminergic innervation of the amygdala, as GAP-43 is known to occur in monoaminergic systems. Nuclei involved in high levels of the cortical processing hierarchy such as the lateral or basal nucleus display a late occurrence of GAP-43-immunoreactivity. In general, anti-GAP-43 has been shown to be an appropriate tool to investigate axonal growth and synaptogenesis in the developing human brain.

Alterations in the organization of the isocortical layer I in trisomy 22

The isocortical layer I of human fetal brains obtained from different cases of chromosomal abnormalities (trisomy 18, 21, 22) and controls without pathological disturbances were investigated histologically and immunohistochemically by using the antibodies SMI 311, SMI 35 and SMI 81 (SNAP 25) as well as antibodies against GAP 43 and calretinin. In cases of trisomy 22 the Cajal-Retzius cells in Nissl-sections and in SMI 311-immunopreparations do not reveal any alterations regarding their location or morphology. However, the axonal plexus, selectively labelled with SMI 35, normally located in layer Ib, is malpositioned in Ia. Likewise, SNAP 25- and GAP 43-immunoreactive structures, which were taken as signs of synaptogenesis, are displaced and appear in Ia instead of Ib. Cases of trisomy 18 and 21 show no changes within the organization of layer I. In trisomy 22 the isocortical layer I reveals malpositioned axonal plexus and a corresponding displacement of synaptic proteins. The possible significance of this alteration in the developmental process of the isocortex is discussed.

Evolution of Alzheimer's disease related cortical lesions

Alzheimer's disease is an immutably progressing dementing disorder. Its major pathologic hallmark is the gradual development of neurofibrillary changes in a few susceptible nerve cell types. The cortical changes do not occur inevitably with advancing age. Once the disease has begun, spontaneous recovery or remissions are not observed. The initial changes develop in poorly myelinated areas of the temporal lobe. The destructive process then follows a predictable pattern as it extends into other cortical areas. Advanced age is not a prerequisite for the evolution of the lesions. Alzheimer's disease is thus an age-related, but not an age-dependent disease. The spread of the neurofibrillary changes resembles the process of cortical myelination, however in reverse order.

Transient features of the thalamic reticular nucleus in the human foetal brain

The architectonic organization and neuronal types of the human foetal reticular nucleus (RN)--with special reference to transient characteristics--have been investigated using antisera against calretinin, parvalbumin and neurofilament epitopes of somata and dendrites (SMI 311). The RN consists of four subdivisions (clearly distinguishable in the 6/7th gestational month): The main portion appears as a prominent structure on account of its extension and high packing density of neurons which coexpress calretinin and parvalbumin. These two calcium-binding proteins are also expressed by the perireticular nucleus forming a conspicuous grey within the internal capsule. Perireticular cells form clusters which are in continuity with the main portion, globus pallidus, ganglionic eminence and pregeniculate nucleus. In double-labellings, a medial subnucleus stands out distinctly as it only expresses calretinin. SMI 311-immunopreparations show neurons revealing a high degree of diversification and elaborated dendritic trees. Several transient characteristics become obvious: the perireticular nucleus, not visible in the adult, represents a distinct entity in the human foetal brain. The main portion and the pregeniculate nucleus appearing as prominent greys are dramatically reduced in size later on. The percentage of RN-neurons expressing calretinin, the diversity of neuronal types and elaborated dendritic trees are reduced. The transient features can be correlated with the RN's putative functional roles in development: early RN-afferents to the dorsal thalamus may represent pioneer fibres providing guiding cues for outgrowing axons from or into the thalamus. Moreover, the RN may serve as an intermediate target for growing axons which are sorted and directed towards different final targets.

[Evaluating the risk of sciatic nerve damage in the rabbit by administration of low and intermediate energy extracorporeal shock waves]

AIM

The aim of the study was to evaluate the likeliness for peripheral nerve lesions following extracorporeal shock wave application.

MATERIAL AND METHOD

82 rabbit sciatic nerves were randomized to undergo low-energetic (0.08 mJ/mm2), middle-energetic (0.28 mJ/mm2) or no (controls) shock wave therapy. After 1 to 28 days an independent neuropathologist checked the specimen for signs of neural lesions.

RESULTS

Only after 14 and 28 days vacuolic swelling of the axons was noted, somewhat pronounced in the middle-energetic group. In no case was there any disruption of the nerve's continuity. We did not observe any neurapraxia.

CONCLUSION

Shock wave application does not threaten peripheral nerve integrity in an animal model.