Showing papers by "University of Würzburg published in 1996"

Association of Anxiety-Related Traits with a Polymorphism in the Serotonin Transporter Gene Regulatory Region

Abstract: Transporter-facilitated uptake of serotonin (5-hydroxytryptamine or 5-HT) has been implicated in anxiety in humans and animal models and is the site of action of widely used uptake-inhibiting antidepressant and antianxiety drugs. Human 5-HT transporter (5-HTT) gene transcription is modulated by a common polymorphism in its upstream regulatory region. The short variant of the polymorphism reduces the transcriptional efficiency of the 5-HTT gene promoter, resulting in decreased 5-HTT expression and 5-HT uptake in lymphoblasts. Association studies in two independent samples totaling 505 individuals revealed that the 5-HTT polymorphism accounts for 3 to 4 percent of total variation and 7 to 9 percent of inherited variance in anxiety-related personality traits in individuals as well as sibships.

Excitation energies from time-dependent density-functional theory.

Abstract: A new density-functional approach to calculate the excitation spectrum of many-electron systems is proposed. It is shown that the full linear density response of the interacting system, which has poles at the exact excitation energies, can rigorously be expressed in terms of the response function of the noninteracting (Kohn-Sham) system and a frequency-dependent exchange-correlation kernel. Using this expression, the poles of the full response function are obtained by systematic improvement upon the poles of the Kohn-Sham response function. Numerical results are presented for atoms.

Attempted suicide in Europe: rates, trends and sociodemographic characteristics of suicide attempters during the period 1989-1992. Results of the WHO/EURO Multicentre Study on Parasuicide

Abstract: The World Health Organization/EURO Multicentre Project on Parasuicide is part of the action to implement target 12 of the WHO programme, "Health for All by the Year 2000', for the European region. Sixteen centres in 13 European countries are participating in the monitoring aspect of the project, in which trends in the epidemiology of suicide attempts are assessed. The highest average male age-standardized rate of suicide attempts was found for Helsinki, Finland (314/100,000), and the lowest rate (45/100,000) was for Guipuzcoa, Spain, representing a sevenfold difference. The highest average female age-standardized rate was found for Cergy-Pontoise, France (462/100,000), and the lowest (69/100,000) again for Guipuzcoa, Spain. With only one exception (Helsinki), the person-based suicide attempt rates were higher among women than among men. In the majority of centres, the highest person-based rates were found in the younger age groups. The rates among people aged 55 years or over were generally the lowest. For the majority of the centres, the rates for individuals aged 15 years or over decreased between 1989 and 1992. The methods used were primarily "soft' (poisoning) or cutting. More than 50% of the suicide attempters made more than one attempt, and nearly 20% of the second attempts were made within 12 months after the first attempt. Compared with the general population, suicide attempters more often belong to the social categories associated with social destabilization and poverty.

Increased MRI activity and immune activation in two multiple sclerosis patients treated with the monoclonal anti-tumor necrosis factor antibody cA2

Abstract: There is evidence that treatment with an antibody to tumor necrosis factor alpha (TNF alpha) improves an animal model of multiple sclerosis (MS) and is beneficial in two systemic inflammatory disease in humans, but there are no reports about anti-TNF treatment of MS. Therefore, we treated two rapidly progressive MS patients with intravenous infusions of a humanized mouse monoclonal anti-TNF antibody (cA2) in an open-label phase I safety trial and monitored their clinical status, gadolinium-enhanced brain magnetic resonance imaging (MRI), and peripheral blood and cerebrospinal fluid (CSF) immunologic status. We did not notice any clinically significant neurologic changes in either patient. The number of gadolinium-enhancing lesions increased transiently after each treatment in both patients. CSF leukocyte counts and IgG index increased after each treatment. The transient increase in the number of gadolinium-enhancing lesions that followed each infusion of cA2 together with the increase in cells and immunoglobulin in the CSF of each patient suggest that the treatment caused immune activation and an increase in disease activity. These results suggest that further use of cA2 in MS is not warranted and that studies of other agents that antagonize TNF alpha should be carried out with frequent monitoring of gadolinium-enhanced MRIs.

A novel functional polymorphism within the promoter of the serotonin transporter gene: possible role in susceptibility to affective disorders

Abstract: The serotonin transporter (5-HTT) is a candidate locus for aetiological involvement in affective disorders. Biochemical studies in suicides and depressed patients suggest that 5-HT uptake function is frequently reduced in affective illness. Furthermore, 5-HTT is targeted by widely used antidepressant drugs such as fluoxetine. We have performed an association study of a short variant of the 5-HTT-linked polymorphic region (5-HTTLPR), which restricts transcriptional activity of the 5-HTT promoter leading to low functional expression of the 5-HTT, in 454 patients with bipolar or unipolar affective disorder and 570 controls, derived from three European Centres (London, Milan and Wurzburg). In all three centres, the frequency of the low activity allele was higher in patients than in controls (50% vs 45% in London, 45% vs 43% in Milan, 47% vs 40% in Wurzburg). Although these differences were not individually significant, a stratified analysis of all three samples gave a significant overall odds ratio of 1.23 (95% confidence interval 1.02-1.49, P = 0.03). The excess of the homozygous low-activity genotype among the patients was even greater (odds ratio 1.53, 95% confidence interval 1.04-2.23, P = 0.02), suggesting partial recessively of the low-activity allele. Given the functional role of 5-HTT, our findings suggest that 5-HTTLPR-dependent variation in functional 5-HTT expression is a potential genetic susceptibility factor for affective disorders. If this finding is replicated, further work on genetic variants with low 5-HTT activity may facilitate the differential diagnosis of affective disorders, the assessment of suicidal behaviour, and the prediction of good clinical response to antidepressants.

Density functional theory of time-dependent phenomena

Abstract: A density-functional formalism comparable to the theory of Hohenberg, Kohn and Sham is developed for electronic systems subject to time-dependent external fields. The formalism leads to a set of time-dependent Kohn-Sham equations which, in addition to the external potential, contain a time-dependent Hartree term and a local time-dependent exchange-correlation potential. Rigorous properties and explicit approximations of the latter are discussed in detail. Generalizations of the basic formalism to incorporate the nuclear motion and to deal with magnetic effects are described. Within the regime of linear-response theory, the time-dependent Kohn-Sham equations lead to a formally exact representation of the frequency-dependent linear density response. Applications within the linear-response regime include the computation of photoabsorbtion cross sections, the determination of van der Waals forces and the calculation of excitation energies. The latter is based on the fact that the frequency-dependent linear density response has poles at the true excitation energies of the interacting many-body system. The time-dependent Kohn-Sham formalism then leads to a simple additive correction of the Kohn-Sham single-particle excitation energies. Beyond the linear-response regime, the time-dependent Kohn-Sham scheme is applied to atoms in strong femto-second laser pulses to describe multi-photon ionization and harmonic generation in a non-perturbative way.

Human bone morphogenetic protein 2 contains a heparin-binding site which modifies its biological activity

Abstract: Bone morphogenetic protein 2 (BMP-2) plays a decisive role during bone regeneration and repair as well as during various stages of embryonal development. A cDNA encoding mature human BMP-2 could be efficiently expressed in Escherichia coli, and after renaturation a dimeric BMP-2 protein of M(r) 26,000 was prepared with a purity greater 98%. The recombinant BMP-2 was functionally active as demonstrated by the induction of alkaline phosphatase activity in the C3H10T1/2 fibroblast cell line (EC50 of 70 nM) and proteoglycan synthesis in embryonic chicken limb bud cells (EC50 of 15-20 nM). A peptide 1-17 representing the N-terminal basic part of BMP-2 as well as heparin increased the specific activity of the protein about fivefold in the limb bud assay. These observations suggested that the N-terminai reduce the specific activity of BMP-2, probably by interacting with heparinic sites in the extracellular matrix. This conclusion was supported by a variant EHBMP-2, where the N-terminal residues 1-12 of BMP-2 had been substituted by a dummy sequence of equal length and which showed an EC50 value of around 1 nM which was affected neither by heparin nor by peptide 1-17. A physical interaction between BMP-2 and heparin could be seen in biosensor experiments, where BMP-2 bound to immobilized heparin with a dissociation constant, Kd, of approximately 20 nM, whereas the heparin-binding of variant EHBMP-2 was negligible. These results identify the basic N-terminal domains of dimeric BMP-2 as heparin-binding sites that are not obligatory for receptor activation but modulate its biological activity.

Animal models of Parkinson's disease: an empirical comparison with the phenomenology of the disease in man.

Abstract: Animal models are an important aid in experimental medical science because they enable one to study the pathogenetic mechanisms and the therapeutic principles of treating the functional disturbances (symptoms) of human diseases Once the causative mechanism is understood, animal models are also helpful in the development of therapeutic approaches exploiting this understanding On the basis of experimental and clinical findings Parkinson's disease (PD) became the first neurological disease to be treated palliatively by neurotransmitter replacement therapy The pathological hallmark of PD is a specific degeneration of nigral and other pigmented brainstem nuclei, with a characteristic inclusion, the Lewy body, in remaining nerve cells There is now a lot of evidence that degeneration of the dopaminergic nigral neurones and the resulting striatal dopamine-deficiency syndrome are responsible for its classic motor symptoms akinesia and bradykinesia PD is one of many human diseases which do not appear to have spontaneously arisen in animals The characteristic features of the disease can however be more or less faithfully imitated in animals through the administration of various neurotoxic agents and drugs disturbing the dopaminergic neurotransmission The cause of chronic nigral cell death in PD and the underlying mechanisms remain elusive The partial elucidation of the processes underlie the selective action of neurotoxic substances such as 6-hydroxydopamine (6-OHDA) or 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), has however revealed possible molecular mechanisms that give rise to neuronal death Accordingly, hypotheses concerning the mechanisms of these neurotoxines have been related to the pathogenesis of nigral cell death in PD The present contribution starts out by describing some of the clinical, pathological and neurochemical phenomena of PD The currently most important animal models (eg the reserpine model, neuroleptic-induced catalepsy, tremor models, experimentally-induced degeneration of nigro-striatal dopaminergic neurons with 6-OHDA, methamphetamine, MPTP, MPP+, tetrahydroisoquinolines, β-carbolines, and iron) critically reviewed next, and are compared with the characteristic features of the disease in man

Invertebrate Synapsins: A Single Gene Codes for Several Isoforms in Drosophila

Abstract: Vertebrate synapsins constitute a family of synaptic proteins that participate in the regulation of neurotransmitter release. Information on the presence of synapsin homologs in invertebrates has been inconclusive. We have now cloned a Drosophila gene coding for at least two inferred proteins that both contain a region with 50% amino acid identity to the highly conserved vesicle- and actin-binding “C” domain of vertebrate synapsins. Within the C domain coding sequence, the positions of two introns have been conserved exactly from fly to human. The positions of three additional introns within this domain are similar. The Drosophila synapsin gene ( Syn ) is widely expressed in the nervous system of the fly. The gene products are detected in all or nearly all conventional synaptic terminals. A single amber (UAG) stop codon terminates the open reading frame (ORF1) of the most abundant transcript of the Syn gene 140 amino acid codons downstream of the homology domain. Unexpectedly, the stop codon is followed by another 443 in-frame amino acid codons (ORF2). Using different antibodies directed against ORF1 or ORF2, we demonstrate that in the adult fly small and large synapsin isoforms are generated. The small isoforms are only recognized by antibodies against ORF1; the large isoforms bind both kinds of antibodies. We suggest that the large synapsin isoform in Drosophila may be generated by UAG read-through. Implications of such an unconventional mechanism for the generation of protein diversity from a single gene are discussed.

Taste receptor-like cells in the rat gut identified by expression of alpha-gustducin

Abstract: The alpha-subunit of the trimeric G-protein complex specific for taste receptor cells of the tongue, alpha-gustducin, is described here to be also expressed in the stomach and intestine. The alpha-gustducin-containing cells were identified as brush cells that are scattered throughout the surface epithelium of the gut and share structural features of taste receptor cells of the tongue. These findings provide clues to the long-sought molecular and cellular basis for chemoreception in the gut.

Bcl-2 interacting protein, BAG-1, binds to and activates the kinase Raf-1

Abstract: The Bcl-2 protein blocks programmed cell death (apoptosis) through an unknown mechanism. Previously we identified a Bcl-2 interacting protein BAG-1 that enhances the anti-apoptotic effects of Bcl-2. Like BAG-1, the serine/threonine protein kinase Raf-1 also can functionally cooperate with Bcl-2 in suppressing apoptosis. Here we show that Raf-1 and BAG-1 specifically interact in vitro and in yeast two-hybrid assays. Raf-1 and BAG-1 can also be coimmunoprecipitated from mammalian cells and from insect cells infected with recombinant baculoviruses encoding these proteins. Furthermore, bacterially-produced BAG-1 protein can increase the kinase activity of Raf-1 in vitro. BAG-1 also activates this mammalian kinase in yeast. These observations suggest that the Bcl-2 binding protein BAG-1 joins Ras and 14-3-3 proteins as potential activators of the kinase Raf-1.

No .NO from NO synthase.

Abstract: The nitric-oxide synthase (NOS; EC 1.14.13.39) reaction is formulated as a partially tetrahydrobiopterin (H4Bip)-dependent 5-electron oxidation of a terminal guanidino nitrogen of L-arginine (Arg) associated with stoichiometric consumption of dioxygen (O2) and 1.5 mol of NADPH to form L-citrulline (Cit) and nitric oxide (.NO). Analysis of NOS activity has relied largely on indirect methods such as quantification of nitrite/nitrate or the coproduct Cit; we therefore sought to directly quantify .NO formation from purified NOS. However, by two independent methods, NOS did not yield detectable .NO unless superoxide dismutase (SOD; EC 1.15.1.1) was present. In the presence of H4Bip, internal .NO standards were only partially recovered and the dismutation of superoxide (O2-.), which otherwise scavenges. .NO to yield ONOO-, was a plausible mechanism of action of SOD. Under these conditions, a reaction between NADPH and ONOO- resulted in considerable overestimation of enzymatic NADPH consumption. SOD lowered the NADPH:Cit stoichiometry to 0.8-1.1, suggesting either that additional reducing equivalents besides NADPH are required to explain Arg oxidation to .NO or that .NO was not primarily formed. The latter was supported by an additional set of experiments in the absence of H4Bip. Here, recovery of internal .NO standards was unaffected. Thus, a second activity of SOD, the conversion of nitroxyl (NO-) to .NO, was a more likely mechanism of action of SOD. Detection of NOS-derived nitrous oxide (N2O) and hydroxylamine (NH2OH), which cannot arise from .NO decomposition, was consistent with formation of an .NO precursor molecule such as NO-. When, in the presence of SOD, glutathione was added, S-nitrosoglutathione was detected. Our results indicate that .NO is not the primary reaction product of NOS-catalyzed Arg turnover and an alternative reaction mechanism and stoichiometry have to be taken into account.

Distribution and characterization of microglia/macrophages in human brain tumors.

Abstract: The role of inflammatory reactions in brain tumors is still unclear. In particular, there is little information about the participation of the microglia/macrophage cell system. We therefore investigated 72 surgical biopsy samples of brain tumors (astrocytoma, glioblastoma, oligodendroglioma, ependymoma, medulloblastoma, cerebral lymphoma, gangliocytoma, neurocytoma and germinoma) and the brains of eight cases with malignant gliomas that came to autopsy, using immunohistochemical markers for the monocyte/macrophage lineage (Ki-M1P, HLA-DR, KP1, My4, My7, Ki-M1, Ki-M6, EBM 11). These markers allowed us to characterize four subtypes of the microglia/macrophage cell system: ramified microglia, ameboid microglia, perivascular microglia and brain macrophages. Among the different tumors, glioblastomas and anaplastic gliomas showed the largest number of mixed cell populations, which consisted of macrophages and ramified and ameboid microglia. In glial tumors of low malignancy fewer, predominantly ameboid, microglia were found. Neuronal tumors showed only a mild increase of microglia. Cerebral lymphomas contained macrophages diffusely distributed within the tumor center, while activated microglia were prominent at the border zone and in the adjacent brain tissue. The autopsy cases were used to study the morphometric distribution of microglia/macrophages. There was a significant increase of microglia/macrophages within the tumor, but no differences were seen between central and peripheral tumor areas. The non-neoplastic gray and white matter contained more microglial cells than controls. We conclude that the distribution pattern of ameboid and ramified microglial cells and macrophages is distinct in most of the investigated tumor types, underlining the complex immunological function of the microglia/macrophage cell system.

Human Papillomavirus Infections in Nonmelanoma Skin Cancers From Renal Transplant Recipients and Nonimmunosuppressed Patients

Abstract: Background : Nonmelanoma carcinomas of the skin represent the most frequent cancers among the Caucasian population worldwide. They occur with high frequency in renal allograft recipient patients after prolonged immunosuppression. Purpose : We analyzed tumors obtained from both immunosuppressed and nonimmunosuppressed patients for human papillomavirus (HPV) DNA. Methods : Twenty-nine specimens of nonmelanoma carcinomas of the skin were obtained from 19 renal allograft recipient patients ; these included 20 specimens of squamous cell carcinoma (SCC) from 11 patients, five specimens of basal cell carcinoma (BCC) from four patients, and four specimens of carcinoma in situ (CIS) from four patients. Forty-one specimens of nonmelanoma carcinomas of the skin were obtained from 32 nonimmunosuppressed patients ; these included 26 SCC specimens from 19 patients, 11 BCC specimens from nine patients, and four keratoacanthoma (benign epithelial tumor) specimens from four patients. A polymerase chain reaction method involving use of degenerate oligonucleotide primers, in which the conserved region of the open reading frame of the HPV L1 (major capsid protein) gene is amplified, was used to amplify total cellular DNA purified from individual tumors. The DNA of each specimen was subjected to 16 different amplification reactions ; different primer combinations were used in order to increase the sensitivity and specificity of HPV detection. Resulting products were probed with a radioactively labeled, degenerate oligonucleotide. HPV-specific DNA was either sequenced directly after elution from the gel or amplified with semi-nested, degenerate primers, after which the products were cloned and sequenced. Sequences were compared with all known papillomavirus sequences. Results : Thirteen (65%) of the 20 SCC specimens and three of the five BCC specimens from immunosuppressed (renal allograft recipient) patients contained identifiable HPV-related sequences, among them 13 putative novel HPV genomes. In addition, all other malignant tumor specimens from this patient group revealed faint signals upon amplification and hybridization ; the origin of these signals has not been identified in the present study. In nonimmunosuppressed patients, eight (31%) of 26 SCC specimens and four (36%) of 11 BCC specimens contained sequences of HPV types. Two putative novel HPV sequences could be identified in this group. Faint signals of yet undetermined origin were observed in eight of the SCC specimens and in two of the BCC specimens. Two of four keratoacanthoma specimens contained sequences of known HPV type. (Keratoacanthoma is a nonmalignant lesion for which the natural history has not been defined.) The spectrum of HPV types in both groups of patients differed substantially. Conclusions : These data point to the frequent presence of HPV sequences in SCCs and BCCs of the skin. The etiologic relationship of these infections to the respective malignant tumors remains to be evaluated. Implications : The presence of HPV DNA in a large percentage of specimens of nonmelanoma carcinomas of the skin from immunosuppressed patients, as well as from nonimmunosuppressed patients, renders a papillomavirus infection as a possible factor in the etiology of this disease

KatP, a novel catalase-peroxidase encoded by the large plasmid of enterohaemorrhagic Escherichia coli O157:H7.

Abstract: A gene coding for a catalase-peroxidase activity was identified on a 9.7 kb Smal DNA fragment derived from the large plasmid pO157 of enterohaemorrhagic Escherichia coli (EHEC) O157:H7 strain EDL 933. Nucleotide sequencing revealed an ORF of 2208 bp and predicted a 736 amino acid polypeptide with a molecular mass of 81.8 kDa. This putative protein was found to be highly homologous to members of the bacterial bifunctional catalase-peroxidase family. Analysis of its amino acid sequence revealed the presence of characteristic peroxidase 1 and 2 motifs. In addition, an N-terminal signal sequence was found, suggesting that the catalase-peroxidase is transported through the cytoplasmic membrane. EHEC catalase-peroxidase activities were investigated in cytoplasmic and periplasmic crude extracts as well as in culture supernatants from wild-type and recombinant E. coli strains. EHEC-specific catalase-peroxidase activity was detected primarily in the periplasm in strain EDL 933. The newly discovered enzyme was designated KatP, to indicate its plasmid origin. PCR analysis of representative strains of all enteric E. coli pathogroups (i.e. enterohaemorrhagic, enterotoxigenic, enteropathogenic, enteroaggregative and enteroinvasive E. coli) revealed a close association between the occurrence of EHEC-haemolysin and the katP gene in Shiga-like-toxin-producing E. coli O157 strains.

Rapid carrier relaxation in self-assembled inxga1-xas/gaas quantum dots

Abstract: Carrier capture and relaxation processes in self-assembled 15-nm ${\mathrm{In}}_{0.5}$${\mathrm{Ga}}_{0.5}$As/GaAs quantum dots are investigated by means of time-resolved photoluminescence spectroscopy. In a systematic study of photoluminescence rise times and barrier decay times (variation of temperature, excitation energy, and excitation density) we aim to identify the physical mechanisms responsible for fast carrier capture and relaxation in quantum dots. Both processes are separated by using appropriate excitation energies. Carrier capture and relaxation are shown to proceed with rates as high as \ensuremath{\sim}2\ifmmode\times\else\texttimes\fi{}${10}^{10}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$ at low temperature even if less than one electron-hole pair per dot and excitation pulse is created. We interpret our results in terms of multiphonon processes at low excitation densities and in terms of Auger processes at high excitation densities. \textcopyright{} 1996 The American Physical Society.

Impaired Differentiation of Schwann Cells in Transgenic Mice with Increased PMP22 Gene Dosage

Abstract: An intrachromosomal duplication containing the PMP22 gene is associated with the human hereditary peripheral neuropathy Charcot-Marie-Tooth disease type 1A, and PMP22 overexpression as a consequence of increased PMP22 gene dosage has been suggested as causative event in this frequent disorder of peripheral nerves. We have generated transgenic mice that carry additional copies of the pmp22 gene to prove that increased PMP22 gene dosage is sufficient to cause PNS myelin deficiencies. Mice carrying approximately 16 and 30 copies of the pmp22 gene display a severe congenital hypomyelinating neuropathy as characterized by an almost complete lack of myelin and marked slowing of nerve conductions. Affected nerves contain an increased number of nonmyelinating Schwann cells, which do not form onion bulbs but align in association with axons. The mutant Schwann cells are characterized by a premyelination-like state as indicated by the expression of embryonic Schwann cell markers. Furthermore, continued Schwann cell proliferation is observed into adulthood. We hypothesize that Schwann cells are impaired in their differentiation into the myelinating phenotype, leading to a disorder comparable to severe cases of hereditary motor and sensory neuropathies. Our findings, combined with the analysis of heterozygous and homozygous PMP22-deficient mice, indicate that aberrant pmp22 gene copy numbers cause various forms of myelination defects.

Control of the Gene optomotor-blind in Drosophila Wing Development by decapentaplegic and wingless

Abstract: Diffusible factors of several protein families control appendage outgrowth and patterning in both insects and vertebrates. In Drosophila wing development, the gene decapentaplegic (dpp) is expressed along the anteroposterior compartment boundary. Early wingless (wg) expression is involved in setting up the dorsoventral boundary. Interaction between dpp- and wg-expressing cells promotes appendage outgrowth. Here, it is shown that optomotor-blind (omb) expression is required for distal wing development and is controlled by both dpp and wg. Ectopic omb expression can lead to the growth of additional wings. Thus, omb is essential for wing development and is controlled by two signaling pathways.

Age-dependent and task-related morphological changes in the brain and the mushroom bodies of the ant Camponotus floridanus

Abstract: Based on a brief description of the general brain morphology of Camponotus floridanus, development of the brain is examined in ants of different ages (pupa to 10 months). During this period, brain volume increases by approximately 20 % while the antennal lobes and the mushroom body neuropile show a more substantial growth, almost doubling their volume. In addition to the age-dependent changes, the volume of the mushroom body neuropile also increases as a consequence of behavioural activity associated with brood care and foraging. Foraging activity may lead to a more than 50 % additional increase in mushroom body neuropile volume. It is unlikely that the growth of mushroom body neuropile results from cell proliferation because no neurogenesis could be observed in adult ant brains.

Penetration of M cells and destruction of Peyer's patches by Yersinia enterocolitica: an ultrastructural and histological study.

Abstract: Yersinia enterocolitica is enteropathogenic for man and rodents. Previous studies provided evidence that Y. enterocolitica invades the lymphoid follicles of the Peyer's patches (PP) of the small intestine. In this study Y. enterocolitica-induced tissue alterations of the follicle-associated epithelium (FAE) and the underlying PP tissue were analysed by scanning (SEM) and transmission electron microscopy (TEM) as well as by conventional histological examination. For this purpose, an experimental mouse infection model including orogastric infections as well as ileal loop experiments were used. A rapid and selective colonisation of the FAE after orogastric yersinia infection was observed by SEM. TEM studies confirmed that Y. enterocolitica adhered closely to the FAE including M cells and enterocytes. Histological studies and TEM revealed that Y. enterocolitica selectively invaded the PP via M cells but not via other cells of the FAE. One day after Y. enterocolitica infection the FAE was altered and small micro-abscesses comprising yersiniae expressing the major outer-membrane protein YadA were observed immediately beneath the FAE. Adjacent villi were dilated from lymphangiectasis and transmigrating polymorphonuclear leucocytes (PMNL) were found within the epithelium. At 5-7 days after infection the FAE and parts of PP were destroyed. Profound alterations of the cyto-architecture of the PP were due to the enormous recruitment of PMNL. By day 5 after infection, abscesses were found in the mesenteric lymph nodes. However, TEM studies revealed evidence that Y. enterocolitica may disseminate from the PP not only via the lymphatics but also by invasion of blood vessels. Taken together, the results of this study demonstrate that the FAE is the primary site of host-pathogen interaction in Y. enterocolitica infection and that this pathogen penetrates M cells and subsequently induces destruction of the PP.

Ecophysiology of cuticular transpiration: comparative investigation of cuticular water permeability of plant species from different habitats

Abstract: Water permeabilities of astomatous, isolated cuticular membranes (CM) of 24 different plants species were measured. Permeances varied from 1.7×10−11 m·s−1 (Vanilla planifolia leaf) up to 2.1×10−9 m·s−1 (Malus cf. domestica fruit) among different plant species, thus covering a range of over 2 orders of magnitude. Ranking of species according to permeances resulted in four distinct groups. The first group, of species with the lowest cuticular transpiration rates, included evergreen species growing in warm dry tropical climates (e.g. Vanilla planifolia and Monstera deliciosa leaves). The second class, with slightly higher water permeabilities, included evergreen species with typical scleromorphic leaf properties, adapted to a typical mediterranean type of climate with a dry period during the year (e.g. Citrus limon and Olea europaea leaves). The third group of species, where the highest leaf cuticular transpiration rates were observed, included deciduous species normally growing in a tempeate climate (e.g. Juglans regia and Forsythia suspensa leaves). Fruit cuticular membranes (CM) made up the fourth group (e.g. Capsicum annuum and Malus cf. domestica fruits), with even higher permeances than leaves of species from group 3. Thus, it appears that the plant species investigated show ecophysiological adaptations to the climatic demands of their natural habitats in cuticular water permeability.

Inflammatory infiltrates in sural nerve biopsies in Guillain-Barré syndrome and chronic inflammatory demyelinating neuropathy

Abstract: Prompted by observations in experimental autoimmune neuritis we reanalyzed immunohistochemically the inflammatory infiltrates in sural nerve biopsies of 22 cases with Guillain-Barre syndrome (GBS) and 13 cases with chronic inflammatory demyelinating polyneuropathy (CIDP). Endoneurial infiltration of CD3+ T cells was found in 20 cases of GBS (median 5.5 cells/mm(2)) and in 10 cases of CIDP (5 cells). Epineurial T cells were present in all GBS cases (19.5 cells) and in 11 CIDP cases (21 cells). CD68+ macrophages were abundant in these neuropathies and often occurred in endoneurial perivascular clusters. In GBS subgroups the number of endoneurial T cells was significantly higher in patients with hypoesthesia and abnormal electrophysiological findings in the sural nerve. In CIDP hypoesthesia was associated with significantly higher numbers of macrophages. Our study also indicates that other factors including the time point of biopsy or previous corticosteroid treatment may influence the inflammatory cell profile. Quantifying cell infiltration may aid in establishing the diagnosis of an immunoneuropathy in patients with mild and noncharacteristic pathology.