Allergic cross-reactivity: from gene to the clinic

A large number of allergenic proteins have now their complete cDNA sequences determined and in some cases also the 3D structures. It turned out that most allergens could be grouped into a small number of structural protein families, regardless of their biological source. Structural similarity among proteins from diverse sources is the molecular basis of allergic cross-reactivity. The clinical relevance of immunoglobulin E (IgE) cross-reactivity seems to be influenced by a number of factors including the immune response against the allergen, exposure and the allergen. As individuals are exposed to a variable number of allergenic sources bearing homologous molecules, the exact nature of the antigenic structure inducing the primary IgE immune response cannot be easily defined. In general, the 'cross-reactivity' term should be limited to defined clinical manifestations showing reactivity to a source without previous exposure. 'Co-recognition', including by definition 'cross-reactivity', could be used to describe the large majority of the IgE reactivity where co-exposure to a number of sources bearing homologous molecules do not allow unequivocal identification of the sensitizing molecule. The analysis of reactivity clusters in diagnosis allows the interpretation of the patient's reactivity profile as a result of the sensitization process, which often begins with exposure to a single allergenic molecule.

RXR alpha deficiency confers genetic susceptibility for aortic sac, conotruncal, atrioventricular cushion, and ventricular muscle defects in mice

Retinoid-dependent pathways play a central role in regulating cardiac morphogenesis. Recently, we characterized gene-targeted RXR alpha -/- embryos, which display an atrial-like ventricular phenotype with the development of heart failure and lethality at embryonic day 14.5. To quantitate the frequency and complexity of cardiac morphogenic defects, we now use microdissection and scanning electron microscopy to examine 107 wild-type, heterozygous, and homozygous embryos at embryonic day 13.5, 14.5, and 15.5. RXR alpha -/- embryos display complex defects, including ventricular septal, atrioventricular cushion, and conotruncal ridge defects, with double outlet right ventricle, aorticopulmonary window, and persistent truncus arteriosus. In addition, heterozygous RXR alpha embryos display a predisposition for trabecular and papillary muscle defects, ventricular septal defects, conotruncal ridge defects, atrioventricular cushion defects, and pulmonic stenosis. Lastly, we show that the intermediate anatomic phenotype displayed by heterozygous embryos is mirrored in the molecular marker MLC-2a. The intermediate phenotype of RXR alpha heterozygous embryos documents a gene dosage effect for RXR alpha in maintaining normal cardiac morphogenesis. In addition, some defects in RXR alpha mutant mice are phenocopies of human congenital heart defects, thereby suggesting that a relative deficiency in RXR alpha or molecules downstream in its signaling pathway may represent congenital heart disease-susceptibility genes.

Mutations in apoptosis genes: a pathogenetic factor for human disease

Cell death by apoptosis is exerted by the coordinated action of many different gene products. Mutations in some of them, acting at different levels in the apoptosis process, have been identified as cause or contributing factor for human diseases. Defects in the transmembrane tumor necrosis factor receptor 1 (TNF-R1) lead to the development of familial periodic fever syndromes. Mutations in the homologous receptor Fas (also named CD95; Apo-1) are observed in malignant lymphomas, solid tumors and the autoimmune lymphoproliferative syndrome type I (ALPS I). A mutation in the ligand for Fas (Fas ligand; CD95 ligand, Apo-1 ligand), which induces apoptosis upon binding to Fas, was described in a patient with systemic lupus erythematodes and lymphadenopathy. Perforin, an other cytotoxic protein employed by T- and NK-cells for target cell killing, is mutated in chromosome 10 linked cases of familial hemophagocytic lymphohistiocytosis. Caspase 10, a representative of the caspase family of proteases, which plays a central role in the execution of apoptosis, is defect in autoimmune lymphoproliferative syndrome type II (ALPS II). The intracellular pro-apoptotic molecule bcl-10 is frequently mutated in mucosa-associated lymphoid tissue (MALT) lymphomas and various non-hematologic malignancies. The p53, an executioner of DNA damage triggered apoptosis, and Bax, a pro-apoptotic molecule with the ability to perturb mitochondrial membrane integrity, are frequently mutated in malignant neoplasms. Anti-apoptotic proteins like bcl-2, cellular-inhibitor of apoptosis protein 2 (c-IAP2) and neuronal apoptosis inhibitory protein 1 (NAIP1) are often altered in follicular lymphomas, MALT lymphomas and spinal muscular atrophy (SMA), respectively. This article reviews the current knowledge on mutations of apoptosis genes involved in the pathogenesis of human diseases and summarises the gradual transformation of discoveries in apoptosis research into benefits for the clinical management of diseases.

Perinatal and early surgical outcome for the fetus with hypoplastic left heart syndrome: a 5-year single institutional experience

OBJECTIVES

To review our experience with the prenatal diagnosis of hypoplastic left heart syndrome (HLHS). Our goal was to establish the benchmark for perinatal and early surgical outcome in the current era, from a center with an aggressive surgical approach and a cohort with a high level of intention-to-treat.

METHODS

Outcome was assessed in fetuses with HLHS following stratification into high-risk and standard-risk categories. High risk was defined as the presence of any of the following: extracardiac, genetic or chromosomal anomalies; prematurity of < 34 weeks' gestation; additional cardiac findings such as intact or highly restrictive atrial septum, severe degree of tricuspid regurgitation or severe ventricular dysfunction. Standard risk was defined as absence of these risk factors.

RESULTS

Of 240 fetuses evaluated over 5 years, 162 (67.5%) were in the standard-risk group and 78 (32.5%) were in the high-risk group. Of the 240 sets of parents, 38 (15.8%) chose termination or non-intervention at birth at initial prenatal counseling and 185 of the neonates (77.1%) underwent first-stage Norwood surgery with 155 surviving and 30 deaths, giving an overall Norwood operative survival of 83.8%. Breakdown by risk class reveals a significant Norwood operative survival advantage for the standard-risk group (92.8%) over the high-risk group (56.5%) (P < 0.001).

CONCLUSIONS

Following prenatal diagnosis of HLHS, families should be strongly encouraged to undertake comprehensive prenatal evaluation in order to obtain an accurate prognosis. One-third have additional risk factors that limit survival outcome, however two-thirds do not and have an excellent chance of early survival.

Artemisia and Ambrosia hypersensitivity: co-sensitization or co-recognition?

BACKGROUND

Ragweed and mugwort have nearly identical flowering periods. Clinical and serological studies showed that ragweed and mugwort sensitization are often associated and this poses relevant clinical problems in patients for whom specific immunotherapy is warranted.

OBJECTIVE

To establish whether the concurrent ragweed and mugwort pollen hypersensitivity is the result of co-sensitization or of co-recognition by using purified recombinant allergens.

METHODS

Sensitization to ragweed and mugwort pollen was assessed by skin prick test (SPT) in all patients reporting allergic symptoms in August and September. IgE reactivity of sera from 42 patients (26 Amb+/Art+, 14 Amb+/Art-, and two Amb-/Art+) to ragweed and mugwort pollen extract as well as to several recombinant ragweed (rAmb a 1, rAmb a 5, rAmb a 6, rAmb a 8, rAmb a 9, and Amb a 10) and mugwort (rArt v 1, rArt v 4, rArt v 5, rArt v 6, and three EF-hand calcium-binding protein) allergens was detected by dot-blot and ELISA analyses.

RESULTS

IgE reactivity of 372 weed pollen-allergic patients was studied. Mugwort reactivity was strongly associated with ragweed hypersensitivity: only 10/147 (7%) mugwort-hypersensitive patients were not sensitized to ragweed, whereas 225/362 (62%) ragweed-hypersensitive patients were not sensitized to mugwort. In vitro, 90% of ragweed-allergic patients reacted with rAmb a 1. Reactivity to other ragweed allergens ranged between 20% and 35%. Forty-six percent of the mugwort-sensitized patients recognized rArt v 1%, 25% reacted to Art v 4, Art v 5, and Art v 6, and 7% recognized the three-EF hand calcium-binding protein. Immunoblot inhibition experiments showed that pre-incubation with ragweed pollen extract only weakly decreased IgE reactivity to mugwort allergens.

CONCLUSION

Patients showing both ragweed- and mugwort-positive SPT and/or RAST are co-sensitized. Future studies will establish whether IgE reactivity translates into clinical symptoms and, hence, if co-sensitized patients should undergo specific immunotherapy with extracts of both mugwort and ragweed pollen.

Role of diet modification in cancer prevention

Carcinogenesis encompasses a prolonged accumulation of injuries at several different biological levels and include both genetic and biochemical changes in the cells. At each of these levels, there are several possibilities of intervention in order to prevent, slow down or even halt the gradual march of healthy cells towards malignancy. Diet modification is one such possibility. A number of natural foodstuffs, especially fruits and vegetables contain substantial quantities of molecules that have chemopreventive potential against cancer development. Such compounds include vitamins, trace elements and a variety of other molecules with antioxidant properties. Carotenoids, flavanoid polyphenols, isoflavones, catechins, and several other components that found in cruciferous vegetables are molecules that are known to protect against the deleterious effect of reactive oxygen species. A number of epidemiological and experimental studies have shown that vitamin C and E, Beta-carotene and the essential trace element selenium can reduce the risk of cancer. Consistent observations during the last few decades that cancer risk is reduced by a diet rich in vegetables, fruits, legumes, grains and green tea have encouraged research to identify several plant components especially phytochemicals that protect against DNA damage. Many of these substances block specific carcinogen pathways. Dietary supplements are part of an overall health program, along with a high intake of fruits and vegetables that help to combat damage to cells, which in turn may initiate cancer development. This paper will review current knowledge concerning diet modification and cancer prevention with special reference to minerals and trace elements.

Surgical management and indication of left ventricular retraining in arterial switch for transposition of the great arteries with intact ventricular septum

OBJECTIVE

Arterial switch is the operation of reference for the surgical treatment of transposition of the great arteries. In cases of late referral, perinatal complications or early left ventricular (LV) dysfunction, the one stage arterial switch is contra indicated. Anatomical repair remains possible in these patients following a LV retraining.

METHODS

From January 1992 to January 2000, a LV retraining was attempted in 22 patients with transposition of the great arteries with intact ventricular septum (TGA IVS), whereas 470 direct arterial switch and 2 Senning were performed. Indication for LV retraining was based on a combination of factors including: an age older than 3 weeks, a "banana shape" aspect of the inter-ventricular septum and mainly a LV mass <35G/m(2).

RESULTS

The mean age at LV retraining was 3.2 months ranging from 9 days to 8 months. Usually conducted by sterntomy, it associated a loose PA banding with a LV/RV at 65% with a systemico-pulmonary shunt. The first stage was associated with frequent LV dysfunction and the LV retraining was discontinued in two patients in favor of one Senning and one early switch followed by ECMO. One patient died at first stage from a mediastinitis. Nineteen patients underwent a second stage arterial switch that was performed when the LV mass had reached 50 G/m(2) after a mean delay of 10 days, ranging from 5 days to 6 weeks. After a mean follow up of 25 months, there was one non-cardiac late death. The 17 patients followed and leaving with an arterial switch are in NYHA class I, with a mean LV shortening fraction of 39%.

CONCLUSIONS

Arterial switch following LV retraining in TGA IVS is a satisfactory option. The inferior limit of 35 G/m(2) adopted, to indicate LV retraining, seems a safe landmark. The quality of the myocardium generated and the respective roles played by the LV afterload, LV wall shear stress, LV inflow and outflow to induce the LV remodeling remain under debate.

Presence of fever and leukocytosis in acute cholecystitis

STUDY OBJECTIVE

To determine the frequency of fever and leukocytosis in patients presenting to the emergency department with acute cholecystitis (AC).

METHODS

We carried out a retrospective review of charts from 1990 to 1993 at a university-affiliated hospital. Our subjects were ED patients with hepato-iminodiacetic acid (HIDA) scans interpreted as showing AC and who had undergone cholecystectomy during hospitalization. Final diagnosis was determined on the basis of the pathology report. Fever was defined as an oral temperature of 100 degrees F (37.7 degrees C) or greater or a rectal temperature of 100.4 degrees F (38.0 degrees C) or greater. Leukocytosis was defined as a WBC count of 11,000/mm3 or greater.

RESULTS

Of the 198 cases studied, the pathologic diagnosis of nongangrenous AC was made in 103 (52%), gangrenous AC was diagnosed in 51 (26%), and chronic cholecystitis was diagnosed in 44 (22%). In patients with nongangrenous AC, 71% were afebrile, 32% lacked leukocytosis, and 28% lacked fever and leukocytosis. In patients with gangrenous AC, 59% were afebrile, 27% lacked leukocytosis, and 16% lacked fever and leukocytosis.

CONCLUSION

We found that patients with AC diagnosed in the ED frequently lacked fever or leukocytosis. The clinician should not rely on the presence of these signs in making the diagnosis of acute cholecystitis.

Gastric emptying of nondigestible solids in the fasted dog

Gastric emptying of nondigestible solid particles was studied in the fasted dog. Particles of varying sizes (0.5-6.4 mm), density (0.5-2.9 gm/cm3), and surface characteristics were coadministered orally with 50 mL of saline and collected from a permanent duodenal cannula implanted approximately 15 cm from the gastroduodenal junction. The phase of the motility pattern was ascertained by the appearance of bile, which occurs during phase II, as well as by mucus discharge, which stops at the onset of phase I. A lag phase, due to the 'quiet' phase I, was observed in the gastric emptying of coadministered saline. This is in contrast with gastric processing of large volumes (i.e., greater than 200 mL) which can usually be approximated by first-order discharge. Most coadministered saline was discharged before the solid particles. The pH of the duodenal effluent was elevated approximately 1 pH unit during mucus discharge and its pH can be as high as 8.3. In the fasted dog, gastric emptying of nondigestible particles closely followed the gastric motility patterns. The onset of discharge of the particles correlated with the late phase II and the phase III activity. Except for a few cases, which took two migrating motor complexes (MMC), greater than 90% of administered particles was discharged from the stomach after one MMC. The discharged particles were entrapped within mucous plugs. In the fasted state, gastric emptying of nondigestible particles appeared to be independent of size, density, and surface characteristics. Mucus seems to play a significant role in the distribution and discharge of the administered particles.

Microbodies (Glyoxysomes and Peroxisomes) in Cucumber Cotyledons: Correlative Biochemical and Ultrastructural Study in Light- and Dark-grown Seedlings

The changes in activities of glyoxysomal and peroxisomal enzymes have been correlated with the fine structure of microbodies in cotyledons of the cucumber (Cucumis sativus L.) during the transition from fat degradation to photosynthesis in light-grown plants, and in plants grown in the dark and then exposed to light. During early periods of development in the light (days 2 through 4), the microbodies (glyoxysomes) are interspersed among lipid bodies and contain relatively high activities of glyoxylate cycle enzymes involved in lipid degradation. Thereafter, these activities decrease rapidly as the cotyledons expand and become photosynthetic, and the activity of glycolate oxidase rises to a peak (day 7); concomitantly the microbodies (peroxisomes) become preferentially associated with chloroplasts.In seedlings grown in the dark for 10 days, the reserve lipid and the glyoxylate cycle enzyme activities persist for a longer time than in the light; correlated with this, there is a continued association of the microbodies with the lipid bodies. When these dark-grown seedlings are then exposed to 51 hours of the light-dark cycle, peroxisomal marker enzymes increase rapidly in activity, and the microbodies become appressed to chloroplasts. We conclude that the characteristic association observed between glyoxysomes and lipid bodies reflects their mutual involvement in net gluconeogenesis through the conversion of fatty acids to carbohydrate, while the close spatial relationship observed between peroxisomes and chloroplasts at later stages of development reflects their mutual involvement in glycolate metabolism.Although glyoxysomal enzyme activities are dropping rapidly while peroxisomal enzyme activities are increasing rapidly during the transition period in the light, the electron microscopic evidence does not indicate that glyoxysomes are being degraded or peroxisomes are being formed. Since in the dark-grown seedlings the activities of peroxisomal enzymes remain low and do not increase as they do in the light, an opportunity is afforded to compare quantitatively any changes in numbers of microbodies per cell with the changes in activities of glyoxysomal enzymes. It is found that the magnitude of the decrease in numbers of microbodies is considerably less than that of the decrease in glyoxysomal enzyme activities between days 4 and 10. When the cotyledons are exposed to light, peroxisomal enzyme activities increase greatly, but again there is no ultrastructural evidence for the synthesis of a new population of microbodies to accommodate this increase. These results allow us to conclude that the developmental transition from glyoxysomal to peroxisomal function almost certainly does not involve the actual replacement of one population of microbodies by another. Rather, the transition probably occurs within existing particles, either by a sequential functioning of two different kinds of microbodies or by a change in enzyme complement within a single population. Our findings with both light- and dark-grown cotyledons favor the latter possibility. The cytoplasmic invaginations into microbodies seen during greening of both light-grown cotyledons and etiolated cotyledons exposed to light may be morphological manifestations of the mechanism by which the microbodies lose or gain enzymes.

High-efficiency, long-term cardiac expression of foreign genes in living mouse embryos and neonates

BACKGROUND

The development of improved strategies for efficient and reproducible in vivo gene transfer into the murine heart will ultimately allow the intersection of somatic and germline gene transfer strategies to study complex features of cardiac biology and diseases.

METHODS AND RESULTS

For embryonic gene transfer, an adenovirus vector expressing beta-galactosidase was injected in utero into the ventricular cavity of living embryos via microsurgical approaches. The injected embryos were developed to term, and efficient expression of the transgene was detected in all cell types in the heart. For postnatal cardiac gene transfer, adenovirus was injected into the cardiac ventricle of neonatal mice, resulting in efficient expression of the transgene in the outer layer of the myocardium as well as cardiomyocytes in the middle and inner layers of the cardiac wall. Mice examined after 3 weeks displayed a pattern of expression that completely mimicked the pattern seen after 3 days, and gene expression was also found after 6 months. The infected myocytes can be identified by coinfection of an adenovirus expressing green fluorescent protein without affecting their normal physiological function.

CONCLUSIONS

We have developed a new strategy to achieve efficient and long-term foreign gene expression in both embryonic and postnatal mouse myocardium via direct intracardiac injection of recombinant adenovirus. The strategy should allow the functional assessment of the expression of dominantly acting exogenous genes, overexpression of wild-type genes, and Cre recombinase-mediated gene ablations at the single-cell level in the context of the intact adult mouse myocardium.

Molecular and immunological characterization of novel weed pollen pan-allergens

BACKGROUND

Pan-allergens like profilins, calcium-binding proteins (CBPs), and nonspecific lipid transfer proteins have been suggested as possible specific markers for multiple pollen sensitizations, and could be used to predict cross-sensitization/poly-sensitization to several pollen allergens. Therefore, the purification and characterization of cross-reacting allergens in pollen is an extremely important task towards correct allergy diagnosis.

METHODS

New pan-allergens were identified by screening a ragweed pollen cDNA library with sera of patients allergic to mugwort pollen. Resulting proteins were cloned, expressed, purified and characterized.

RESULTS

We report complete cDNA sequences of two profilin isoforms (Amb a 8.01 and Amb a 8.02), two isoforms of a 2EF-hand CBP (Amb a 9.01 and Amb a 9.02), a new 3EF-hand CBP (Amb a 10) from ragweed pollen and a 2EF-hand CBP from mugwort (Art v 5). All these proteins were expressed in Escherichia coli, purified to homogeneity and characterized by biochemical and immunological means.

CONCLUSIONS

The identified proteins are novel pan-allergens and can be used as diagnostic markers for polysensitization and used in component-resolved diagnosis.

The occurrence of glycolate dehydrogenase and glycolate oxidase in green plants: an evolutionary survey

Homogenates of various lower land plants, aquatic angiosperms, and green algae were assayed for glycolate oxidase, a peroxisomal enzyme present in green leaves of higher plants, and for glycolate dehydrogenase, a functionally analogous enzyme characteristic of certain green algae. Green tissues of all lower land plants examined (including mosses, liverworts, ferns, and fern allies), as well as three freshwater aquatic angiosperms, contained an enzyme resembling glycolate oxidase, in that it oxidized l- but not d-lactate in addition to glycolate, and was insensitive to 2 mm cyanide. Many of the green algae (including Chlorella vulgaris, previously claimed to have glycolate oxidase) contained an enzyme resembling glycolate dehydrogenase, in that it oxidized d- but not l-lactate, and was inhibited by 2 mm cyanide. Other green algae had activity characteristic of glycolate oxidase and, accordingly, showed a substantial glycolate-dependent O(2) uptake. It is pointed out that this distribution pattern of glycolate oxidase and glycolate dehydrogenase among the green plants may have phylogenetic significance.Activities of catalase, a marker enzyme for peroxisomes, were also determined and were generally lower in the algae than in the land plants or aquatic angiosperms. Among the algae, however, there were no consistent correlations between levels of catalase and the type of enzyme which oxidized glycolate.

Prevalence of IgE-binding to Art v 1, Art v 4 and Amb a 1 in mugwort-allergic patients

BACKGROUND

Mugwort (Artemisia vulgaris) represents an important source of weed pollen allergens. The objectives of the present study were (i) to analyze the IgE binding profiles in a group of mugwort-allergic patients, (ii) to identify individual marker allergens crucial for the diagnosis of mugwort allergy and (iii) to identify potential crossreactive allergens present in ragweed (Ambrosia artemisiifolia) pollen extract.

METHODS

Sera from 100 pediatric mugwort-allergic patients were analyzed for their IgE binding pattern to natural mugwort and ragweed pollen proteins, purified natural and recombinant Art v 1, recombinant Art v 4 and recombinant Amb a 1 using immunoblots and ELISA.

RESULTS

91% of the patients' sera tested displayed IgE binding to one or more mugwort pollen allergens in ELISA and 88% were positive in immunoblot. Purified natural Art v 1 was recognized by 79%, the recombinant protein by 39% of the patients tested and purified recombinant Art v 4 by 34% of the patients' sera. 67% of the sera displayed crossreactive IgE to one or more ragweed pollen allergens. Recombinant Amb a 1 was noted in only 14% of the mugwort-allergic sera.

CONCLUSIONS

Allergen-specific in vitro diagnosis was performed in 100 pediatric mugwort-allergic serum samples. Using two allergens (Art v 1 and Art v 4), 91% of the patients could be identified as mugwort pollen-sensitized patients by IgE in vitro tests. Crossreactivity to ragweed pollen allergens was demonstrated by in vitro experiments, suggesting a new important and potent allergen source expanding across Europe.

Apo CIII gene transcription is regulated by a cytokine inducible NF-kappa B element

Overproduction of Apo CIII causes elevated plasma triglyceride levels in transgenic animals and is associated with hypertriglyceridemia in humans. The regulation of apo CIII production is likely to play an important role in controlling plasma triglyceride levels. As an initial step in determining the role of transcriptional regulation in the production of apo CIII and in triglyceride metabolism, we have begun to characterize the activity of specific transcriptional regulatory elements in the CIII promoter. In the current study, we have identified and characterized an NF-kappa B regulatory element located 150 nucleotides upstream from the transcriptional start site of the apo CIII gene. Purified NF-kappa B, as well as an NF-kappa B protein in HepG2 cell nuclear extracts, bound specifically to this sequence element. The hepatic protein was induced by phorbol ester (PMA), and reacted with antibodies to the p50 and p65 subunits of NF-kappa B. The NF-kappa B element conferred PMA and IL1-beta inducible transcriptional activity to a heterologous promoter/reporter construct when transfected into HepG2 cells. Analysis of the full length CIII promoter demonstrated that the inducible activity of the NF-kappa B element was suppressed by sequences in the apo CIII enhancer element located approximately 500 nucleotides upstream of the NF-kappa B binding site. A deletion removing the enhancer restored the PMA inducible activity of the NF-kappa B binding site. These results indicate that apo CIII gene expression is regulated by NF-kappa B, and suggest that apo CIII production may be modulated by cellular signals, like inflammatory cytokines, that activate NF-kB.

The development of microbodies and peroxisomal enzymes in greening bean leaves

The ontogeny of leaf microbodies (peroxisomes) has been followed by (a) fixing primary bean leaves at various stages of greening and examining them ultrastructurally, and (b) homogenizing leaves at the same stages and assaying them for three peroxisomal enzymes. A study employing light-grown seedlings showed that when the leaves are still below ground and achlorophyllous, microbodies are present as small organelles (e.g., 0.3 microm in diameter) associated with endoplasmic reticulum, and that after the leaves have turned green and expanded fully, the microbodies occur as much larger organelles (e.g., 1.5 microm in diameter) associated with chloroplasts. Specific activities of the peroxisomal enzymes increase 3- to 10-fold during this period. A second study showed that when etiolated seedlings are transferred to light, the microbodies do not appear to undergo any immediate morphological change, but that by 72 h they have attained approximately the size and enzymatic activity possessed by microbodies in the mature primary leaves of light-grown plants. It is concluded from the ultrastructural observations that leaf microbodies form as small particles and gradually develop into larger ones through contributions from smooth portions of endoplasmic reticulum. In certain aspects, the development of peroxisomes appears analogous to that of chloroplasts. The possibility is examined that microbodies in green leaves may be relatively long-lived organelles.

A correlative ultrastructural and enzymatic study of cotyledonary microbodies following germination of fat-storing seeds

Sunflower, cucumber, and tomato cotyledons, which contain microbodies in both the early lipid-degrading and the later photosynthetic stages of post-germinative growth, were processed for electron microscopy according to conventional procedures and examined 1, 4 and 7 days after germination. Homogenates of sunflower cotyledons were assayed for enzymes characteristic of glyoxysomes and leaf peroxisomes (both of which are defined morphologically as microbodies) at stages corresponding to the fixations for electron microscopy. The particulate nature of these enzymes was demonstrated by differential and equilibrium density centrifugation, making it possible to relate them to the microbodies seen in situ.One day after germination, the microbodies are present as small organelles among large numbers of protein and lipid storage bodies; the cell homogenate contains catalase but no detectable isocitrate lyase (characteristic of glyoxysomes) or glycolic acid oxidase (characteristic of leaf peroxisomes). 4 days after germination, numerous microbodies (glyoxysomes) are in extensive and frequent contact with lipid bodies. The microbodies often have cytoplasmic invaginations. At this stage the cells are rapidly converting lipids to carbohydrates, and the homogenate has high isocitrate lyase activity. 7 days after germination, microbodies (peroxisomes) are appressed to chloroplasts and frequently squeezed between them in the green photosynthetic cells. The homogenate at this stage has substantial glycolic acid oxidase activity but a reduced level of isocitrate lyase. It is yet to be determined whether the peroxisomes present at day 7 are derived from preexisting glyoxysomes or arise as a separate population of organelles.

Chemoselective synthesis of peptides containing major advanced glycation end-products of lysine and arginine

Useful methodologies have been developed, enabling the straightforward synthesis of peptides containing N(epsilon)-(carboxymethyl)-L-lysine (CML) and N(epsilon)-(carboxyethyl)-L-lysine (CEL), the major glycation end-products of lysine. These lysine derivatives were successfully incorporated into growing peptide chains via standard Fmoc/Ot-Bu peptide synthesis procedures. For the synthesis of peptides containing major glycation end-products of arginine, synthetic routes have been developed enabling the transformation of ornithine residues in peptides into the well-known arginine-derived advanced glycation end-products (AGEs) Glarg, carboxymethyl-L-arginine (CMA), MG-H1, MG-H2, MG-H3, and carboxyethyl-L-arginine (CEA), respectively, by means of special modifying agents. Furthermore, it was shown that Glarg-containing peptides become quantitatively hydrolyzed into CMA-peptides under physiologic conditions. A similar reaction was observed in case of a MG-H3-peptide, which turned into a CEA-peptide under these conditions.

Intermediate filament antigens of 60 and 65 kDa in the nuclear matrix of plants: their detection and localization

Although the presence of a matrix in plant nuclei has been reported, major questions remain about its structural and biochemical features. We have used an intermediate filament antibody of broad specificity to explore whether Daucus carota (carrot) nuclei and nuclear matrices contain intermediate filament/lamin antigens and, if so, where specifically they are localized. SDS-PAGE and Western blotting revealed two bands, at 60 and 65 kDa, that were highly immunoreactive with the intermediate filament antibody (IFA) of Pruss et al. (1981, Cell 27, 419-428). This pattern was observed consistently, not only with carrot cell-free nuclei and nuclear matrices, but also with nuclear preparations from Vicia faba (broad bean) and Pisum sativum (pea). Immunofluorescence studies with whole carrot nuclei localized the IFA antigens to the nucleoplasm and disclosed no accentuated peripheral labeling. Agarose-embedded nuclear matrices showed not only fluorescence throughout the nucleoplasm but also heavy labeling surrounding the nucleoli and suggestions of peripheral labeling. At the ultrastructural level, immunogold results from pre- and postembedment treatments supported the conclusion that IFA antigens occur throughout the nucleoplasm, with possibly a slight concentration at the periphery. These combined results provide substantial evidence that plant nuclei and their matrices possess at least two major intermediate filament antigens with molecular weights characteristic of animal lamins. Whether or not these antigens represent plant lamins, their nonperipheral localization hints at significant differences among the eukaryotic kingdoms in nuclear organization.

Automatic removal of high-amplitude artefacts from single-channel electroencephalograms

In this work, we present a method to extract high-amplitude artefacts from single channel electroencephalogram (EEG) signals. The method is called local singular spectrum analysis (local SSA). It is based on a principal component analysis (PCA) applied to clusters of the multidimensional signals obtained after embedding the signals in their time-delayed coordinates. The decomposition of the multidimensional signals in each cluster is achieved by relating the largest eigenvalues with the large amplitude artefact component of the embedded signal. Then by reverting the clustering and embedding processes, the high-amplitude artefact can be extracted. Subtracting it from the original signal a corrected EEG signal results. The algorithm is applied to segments of real EEG recordings containing paroxysmal epileptiform activity contaminated by large EOG artefacts. We will show that the method can be applied also in parallel to correct all channels that present high-amplitude artefacts like ocular movement interferences or high-amplitude low frequency baseline drifts. The extracted artefacts as well as the corrected EEG will be presented.

Dexterous helical magnetic robot for improved endovascular access

Treating vascular diseases in the brain requires access to the affected region inside the body. This is usually accomplished through a minimally invasive technique that involves the use of long, thin devices, such as wires and tubes, that are manually maneuvered by a clinician within the bloodstream. By pushing, pulling, and twisting, these devices are navigated through the tortuous pathways of the blood vessels. The outcome of the procedure heavily relies on the clinician's skill and the device's ability to navigate to the affected target region in the bloodstream, which is often inhibited by tortuous blood vessels. Sharp turns require high flexibility, but this flexibility inhibits translation of proximal insertion to distal tip advancement. We present a highly dexterous, magnetically steered continuum robot that overcomes pushability limitations through rotation. A helical protrusion on the device's surface engages with the vessel wall and translates rotation to forward motion at every point of contact. An articulating magnetic tip allows for active steerability, enabling navigation from the aortic arch to millimeter-sized arteries of the brain. The effectiveness of the magnetic continuum robot has been demonstrated through successful navigation in models of the human vasculature and in blood vessels of a live pig.

[Compression syndrome of the radial nerve in the area of the supinator groove. Experiences with 110 patients]

Both radial tunnel syndrome and posterior interosseous nerve (PIN) compression syndrome are caused by compression of the posterior interosseous nerve. There is a controversy about certain features of PIN compression especially with regard to diagnostic criteria and therapy as well as differentiation from tennis elbow. From 1992 to 1997, we operated 110 patients because of PIN compression. Diagnosis was based on clinical examination only. As a rule, we decompressed the PIN directly using an anterior approach. With regard to radial tunnel syndrome, we could review 69 from 103 operations with an average follow-up of 41 months. Using the criteria originally proposed by Roles and Maudsley, only 60% showed excellent or good results. The mean DASH score was 32. Recompression of the PIN by scarring was found in as much as 17% of patients and proved to be a serious complication of direct decompression of the PIN. Furthermore, 52% of our patients operated on because of PIN compression suffered from tennis elbow as well. We therefore believe that radial tunnel syndrome is a specific form of tennis elbow. From an anatomical point of view, the inseparable origin of the radial wrist extensors and supinator muscle seems to link tennis elbow and radial tunnel syndrome. To avoid recompression of the PIN by scarring, we have abandoned direct decompression and now routinely use Wilhelm's denervation procedure for the treatment of tennis elbow as well as radial tunnel syndrome. This procedure indirectly decompresses the PIN by cutting the superficial origin of the supinator muscle with consecutive relaxation of Frohse's arcade. Preliminary results are promising and show improvement of preoperative neurologic status by indirect decompression.

Downregulation of atrial markers during cardiac chamber morphogenesis is irreversible in murine embryos

Vertebrate cardiogenesis is a complex process involving multiple, distinct tissue types which interact to form a four-chambered heart. Molecules have been identified whose expression patterns co-segregate with the maturation of the atrial and ventricular muscle cell lineages. It is not currently known what role intrinsic events versus external influences play in cardiac chamber morphogenesis. We developed novel, fluorescent-based, myocardial, cellular transplantation systems in order to study these questions in murine embryos and report the irreversible nature of chamber specification with respect to the downregulation of atrial myosin light chain 2 (MLC-2a) and alpha myosin heavy chain (alpha-MHC). Grafting ventricular cells into the atrial chamber does not result in upregulation of MLC-2a expression in ventricular cells. Additionally, wild-type ventricular muscle cells grafted into the wild-type background appropriately downregulate MLC-2a and alpha-MHC. Finally, grafting of RXRalpha gene-deficient ventricular muscle cells into the ventricular chambers of wild-type embryos does not rescue the persistent expression of MLC-2a, providing further evidence that ventricular chamber maturation is an early event. These studies provide a new approach for the mechanistic dissection of critical signaling events during cardiac chamber growth, maturation and morphogenesis in the mouse, and should find utility with other approaches of cellular transplantation in murine embryos. These experiments document the irreversible nature of the downregulation of atrial markers after the onset of cardiogenesis during ventricular chamber morphogenesis and temporally define the response of cardiac muscle cells to signals regulating chamber specification.

Developmental expression of the murine spliceosome-associated protein mSAP49

We have isolated the mouse homologue of human spliceosome-associated protein SAP49, mSAP49. mSAP49 contains two RNA recognition motifs (RRM) in the N terminus of the predicted amino acid sequence, and a highly basic C terminus rich in glycine/proline. mSAP49 displayed a plastic of expression in cardiac development. In the adult mouse, mSAP49 is widely distributed, although it was found at relatively lower levels in the heart. In situ hybridization analysis of mSAP49 mRNA distribution in staged mouse embryos showed that mSAP49 onset occurs later in the heart than in other embryonic tissues. While mSAP49 expression was found at day 10.0 postconception (pc) in the optic eminence, optic vesicle, hindbrain, and somites, it was not in cardiac structures. mSAP49 was detected in the ventricles at day 11.5, and at day 13.5 it was also detected in the atria. Northern analysis showed that mSAP49 mRNA displayed a peak of expression in the heart at days 14.0-15.0 pc, and its abundance decayed in the adult. This dynamic pattern of cardiac expression suggests that mSAP49 may be contributing to a change in the ratio of spliceosome components during cardiac growth and development, which may have consequences for tissue-specific splicing, RNA stabilization, or translation.