Cyst-like cerebral lesions in tuberous sclerosis

Known brain manifestations of tuberous sclerosis (TSC) are cortical sclerotic tubera, giant cell astrocytomas, subependymal calcified nodules in the lateral walls of the lateral ventricles, and white matter heterotopias. In addition, small cyst-like lesions in the white matter have been described. We report on three TSC patients with hitherto undescribed large cyst-like cerebral lesions in subcortical and white matter locations. We emphasize that cystoid brain degeneration is a rare but typical cerebral manifestation of TSC and suggest that, in patients with such lesions, TSC should be taken into consideration.     

Recombinant dissection of myosin heavy chain of Toxocara canis shows strong clustering of antigenic regions

Myosins from nematode parasites elicit strong humoral and cellular immune responses and have been investigated as vaccine candidates. In this study we cloned and sequenced a cDNA coding for myosin heavy chain from Toxocara canis, a nematode parasite of canids which may also infect humans and cause various unspecific symptoms. To determine the major antigenic regions the myosin heavy chain was systematically dissected into ten overlapping recombinant fusion polypeptides which were purified by metal chelate chromatography. Single fragments were then tested for their IgG reactivity in sera from toxocarosis patients and healthy probands. Two regions, one region at the mid to carboxy-terminal end of the head domain and one region in the rod domain, were identified as major antigens, which in combination were positive with 86% of the sera. The other domains were less reactive. This shows that the patients' IgG reactivity was not directed evenly against all parts of the molecule, but was rather clustered in few regions.     

Interinstitutional variations of sensitometric curves of radiographic dosimetric films

Depth and field size dependence of the sensitometric curves of radiographic films have been studied by various groups. Limited information is, however, available on the magnitude of the variations in sensitometric curves applied in clinical practice in different institutions. In this study we assessed in a systematic way the effect of the various parameters influencing the shape of the sensitometric curve: batch composition, irradiation conditions, film processing, and film scanning. Two types of film, Kodak X-Omat V and CEA TVS, were irradiated, processed, and analyzed in three different institutions. The interinstitutional variation of the sensitometric curves, expressed as the OD variation at 50 cGy, can be up to 32% and is mainly caused by differences in film processing and to a lesser degree to differences in batch composition, film scanning, and irradiation conditions. For the Kodak films, the average OD difference at 50 cGy between the three institutions is 17% as a result of differences in batch composition and 25% due to differences in processing conditions. For the CEA films these data are 6% and 24%, respectively. The long-term variation of the sensitometric curves of KODAK films in one institution was smaller than the differences in batch composition between the three institutions. The sensitometric curves of CEA films showed in one institution a large variation with time; the shape gradually varied from sigmoidal to quasilinear. By using relative OD values rather than absolute OD values, variations in sensitometric curves of KODAK films can be reduced to 2%. Consequently, one sensitometric curve is sufficient to derive relative dose values. If processing conditions are well controlled, it might therefore be advantageous to determine the absolute OD only at one or two dose values, in combination with a "universal" relative sensitometric curve.     

The Etruscan skulls of the Rostock anatomical collection — How do they compare with the skeletal findings of the first thousand years B.C.?

Seven Etruscan skulls were found in Corneto Tarquinia in the years 1881 and 1882 and were given as present to Rostock's anatomical collection in 1882. The origin of the Etruscans who were contemporary with the Celts is not yet clear; according to Herodotus they had emigrated from Lydia in Asia Minor to Italy. To fit the Etruscan skulls into an ethnological grid they were compared with skeletal remains of the first thousand years B.C. E. All skulls were found to be male; their age ranged from 20 to 60 years, with an average age of about thirty. A comparison of the median sagittal outlines of the Etruscan skulls and the contemporary Hallstatt-Celtic skulls from North Bavaria showed that the former were shorter and lower. Maximum skull length, minimum frontal breadth, ear bregma height, bizygomatical breadth and orbital breadth of the Etruscan skulls were statistically significantly less developed compared to Hallstatt-Celtics from North Bavaria. In comparison to other contemporary skeletal remains the Etruscan skulls had no similarities in common with Hallstatt-Celtic skulls from North Bavaria and Baden-Württemberg but rather with Hallstatt-Celtic skulls from Hallstatt in Austria. Compared to chronologically adjacent skeletal remains the Etruscan skulls did not show similarities with Early Bronze Age skulls from Moravia but with Latène-Celtic skulls from Manching in South Bavaria. Due to the similarities of the Etruscan skulls with some Celtic skulls from South Bavaria and Austria, it seems more likely that the Etruscans were original inhabitants of Etruria than immigrants.     

Mild phenotype in two unrelated patients with a partial deletion of 21q22.2-q22.3 defined by FISH and molecular studies

We describe two unrelated patients with cytogenetically visible deletions of 21q22.2-q22.3 and mild phenotypes. Both patients presented minor dysmorphic features including thin marfanoid build, facial asymmetry, downward-slanting palpebral fissures, depressed nasal bridge, small nose with bulbous tip, and mild mental retardation (MR). FISH and molecular studies indicated common deleted areas but different breakpoints. In patient 1, the breakpoint was fine mapped to a 5.2 kb interval between exon 5 and exon 8 of the ETS2 gene. The subtelomeric FISH probe was absent on one homologue 21 indicating a terminal deletion spanning approximately 7.9 Mb in size. In patient 2, the proximal breakpoint was determined to be 300-700 kb distal to ETS2, and the distal breakpoint 2.5-0.3 Mb from the 21q telomere, indicating an interstitial deletion sized approximately 4.7-7.3 Mb. The 21q- syndrome is rare and typically associated with a severe phenotype, but different outcomes depending on the size and location of the deleted area have been reported. Our data show that monosomy 21q of the area distal to the ETS2 gene, representing the terminal 7.9 Mb of 21q, may result in mild phenotypes comprising facial anomalies, thin marfanoid build, and mild MR, with or without signs of holoprosencephaly.     

Cells of the central nervous system as targets and reservoirs of the human immunodeficiency virus

The availability of highly active antiretroviral therapies (HAART) has not eliminated HIV-1 infection of the central nervous system (CNS) or the occurrence of HIV-associated neurological problems. Thus, the neurobiology of HIV-1 is still an important issue. Here, we review key features of HIV-1-cell interactions in the CNS and their contributions to persistence and pathogenicity of HIV-1 in the CNS. HIV-1 invades the brain very soon after systemic infection. Various mechanisms have been proposed for HIV-1 entry into the CNS. The most favored hypothesis is the migration of infected cells across the blood-brain barrier ("Trojan horse" hypothesis). Virus production in the CNS is not apparent before the onset of AIDS, indicating that HIV-1 replication in the CNS is successfully controlled in pre-AIDS. Brain macrophages and microglia cells are the chief producers of HIV-1 in brains of individuals with AIDS. HIV-1 enters these cells by the CD4 receptor and mainly the CCR5 coreceptor. Various in vivo and cell culture studies indicate that cells of neuroectodermal origin, particularly astrocytes, may also be infected by HIV-1. These cells restrict virus production and serve as reservoirs for HIV-1. A limited number of studies suggest restricted infection of oligodendrocytes and neurons, although infection of these cells is still controversial. Entry of HIV-1 into neuroectodermal cells is independent of the CD4 receptor, and a number of different cell-surface molecules have been implicated as alternate receptors of HIV-1. HIV-1-associated injury of the CNS is believed to be caused by numerous soluble factors released by glial cells as a consequence of HIV-1 infection. These include both viral and cellular factors. Some of these factors can directly induce neuronal injury and death by interacting with receptors on neuronal membranes (neurotoxic factors). Others can activate uninfected cells to produce inflammatory and neurotoxic factors and/or promote infiltration of monocytes and T-lymphocytes, thus amplifying the deleterious effects of HIV-1 infection. CNS responses to HIV-1 infection also include mechanisms that enhance neuronal survival and strengthen crucial neuronal support functions. Future challenges will be to develop strategies to prevent HIV-1 spread in the brain, bolster intrinsic defense mechanisms of the brain and to elucidate the impact of long-term persistence of HIV-1 on CNS functions in individuals without AIDS.     

Human TLR-7-, -8-, and -9-mediated induction of IFN-alpha/beta and -lambda Is IRAK-4 dependent and redundant for protective immunity to viruses

Five TLRs are thought to play an important role in antiviral immunity, sensing viral products and inducing IFN-alpha/beta and -lambda. Surprisingly, patients with a defect of IRAK-4, a critical kinase downstream from TLRs, are resistant to common viruses. We show here that IFN-alpha/beta and -lambda induction via TLR-7, TLR-8, and TLR-9 was abolished in IRAK-4-deficient blood cells. In contrast, IFN-alpha/beta and -lambda were induced normally by TLR-3 and TLR-4 agonists. Moreover, IFN-beta and -lambda were normally induced by TLR-3 agonists and viruses in IRAK-4-deficient fibroblasts. We further show that IFN-alpha/beta and -lambda production in response to 9 of 11 viruses tested was normal or weakly affected in IRAK-4-deficient blood cells. Thus, IRAK-4-deficient patients may control viral infections by TLR-3- and TLR-4-dependent and/or TLR-independent production of IFNs. The TLR-7-, TLR-8-, and TLR-9-dependent induction of IFN-alpha/beta and -lambda is strictly IRAK-4 dependent and paradoxically redundant for protective immunity to most viruses in humans.     

Seven novel and four recurrent point mutations in the factor VIII (F8C) gene

Haemophilia A is a X‐linked bleeding disorder, caused by deficiency in the activity of coagulation factor VIII due to mutations in the corresponding gene. The most common defect in patients is an inversion of the factor VIII gene that accounts for nearly 45% of individuals with severe hemophilia A. Point mutations and small deletions/insertions are responsible for the majority of cases with moderate to mild clinical course and for half of the severe hemophilia A occurrences. The majority of these mutations are “private”, because of the high mutation rate for this particular gene. We report on eleven pathological changes in the factor VIII sequence detected in male patients with haemophilia A or in female obligate carriers. Seven of these mutations are novel [E204N, E265X, M320T, F436C, S535C, N2129M and R2307P] and four have been previously identified [V162M, R527W, R1966X, and R2159C]. Genotype‐phenotype correlations and computer prediction analysis on the effect of missense mutations on the secondary structure of the factor VIII protein are performed and the relationships evaluated. © 2001 Wiley‐Liss, Inc.     

Studies on intracellular transport of secretory proteins in the rat exocrine pancreas

Summary The possible role of microtubules and microfilaments in the secretory process of the rat exocrine pancreas was analysed in vitro using isolated pancreatic lobules. Colchicine and vinblastine as microtubule inhibitors, hexylene glycol as a microtubule stabilizer, and cytochalasin B as a disruptive agent for microfilaments were used in increasing concentrations to test their effects on protein synthesis, intracellular transport, zymogen discharge, and cellular respiration.Colchicine only at 10^–2 M concentrations inhibits protein synthesis, while vinblastine inhibits at 10^–6 and 10^–5 M by 20% and at 10^–4 M by 55%. A similar inhibition is observed with 1.5% concentrations of hexylene glycol while cytochalasine B at 1,5 and 10 g/ml is without effect on protein synthesis. Colchicine and vinblastine have their major effects on intracellular transport both in secretion studies and cell fractionation experiments. Colchicine in concentrations between 10^–3 to 10^–5 M inhibits discharge of newly synthesized proteins by 50%, while vinblastine shows a dose-response relationship of 40% inhibition at 10^–6 M to 90% at 10^–4 M. Discharge of amylase is uniformly reduced by 30% by both colchicine and vinblastine in the whole dose range. The pronounced effect of colchicine and vinblastine is evident in cell fractionation studies: both drugs inhibit the disappearance of protein radioactivity from microsomes and its appearance in zymogen granules; similarly the peak radioactivity in smooth microsomes (Golgi) appears delayed. No differential effect on the secretory process was observed with 1.5% concentrations of hexylene glycol or cytochalasin B at 1.5 and 10 g/ml concentrations. A fines tructural analysis of microtubules and microfilaments in the exocrine pancreatic cell reveals their distribution in all parts of the cytoplasm and in relation to all cell organelles. Both systems (microtubules, microfilaments) seem to be connected, at least in certain areas of the cytoplasm and at the plasma membrane.The reduction of transport efficiency by microtubule inhibitors results in a deposition of secretory material in the cisternal space of the rough endoplasmatic reticulum, which leads to the formation of paracrystals. Colchicine at 10^–3 M concentrations leads to an enlargement of condensing vacuoles in the Golgi complex.A short communication on the same subject was presented at a Symposion on Stimulus-Secretion-Coupling in the Gastro-intestinal Tract, Titisee (May 27–29, 1975).Supported by Deutsche Forschungsgemeinschaft (Ke 113/8).     

In vitro study on the impact of fish sera on the survival and fine structure of the eel-pathogenic acanthocephalanParatenuisentis ambiguus

The effects of fish sera on the growth and fine structure of infective larvae of the eel-pathogenic acanthocephalanParatenuisentis ambiguus (Eoacanthocephala: Tenuisentidae) were studied under in vitro conditions using sera from the final hostAnguilla anguilla and from two accidental fish hosts as well as fetal calf serum. As controls larvae were also kept in medium in the absence of serum and in experimentally infected eels. Sera from the accidental fish hosts carp and rainbow trout exerted toxic effects on the acanthocephalans. Worms maintained in medium containing sera from these two fish were contracted and displayed inverted probosces. Moreover, the tegument exhibited vacuolization and the formation of necrotic areas, including lysis of the mitochondria. Due to these effects, the parasites died at 21 (rainbow trout) or 21–50 days (carp) postincubation. Eel sera had no toxic effect on the infective larvae. The growth of the larvae in medium depended on the composition of the latter, but was reduced as compared with that in the natural final host. Based on these results, we conclude that components of the hosts' blood sera play a role in the determination of the host specificity ofP. ambiguus.