Nine new Pristionchus (Nematoda: Diplogastridae) species from China

The model organism Pristionchus pacificus and the genus Pristionchus, Kreis, 1932 have been intensively studied in the last decade with contemporary work focusing on the development, evolution, ecology, behavior, neurobiology, and genomics of this group of organisms. In particular, mechanistic studies on the development and evolution of mouth-form plasticity, predation and associated self-recognition processes enabled unique insight into life history strategies and the evolution of novelty. These studies include a comparative research agenda making use of the 39 available species of Pristionchus, all of which can be studied in living cultures. Sampling efforts revealed that Asia represents a biodiversity hotspot for Pristionchus worms. However, previous samplings have a bias towards northern and island areas, largely for logistic reasons. Here, we report on two extensive sampling trips to the Yunnan and Shaanxi provinces in Mainland China. We report the isolation of nine new Pristionchus species by morphology, morphometrics, mating experiments and genome-wide sequence analysis.

Comparative genomics and community curation further improve gene annotations in the nematode Pristionchus pacificus

Background

Nematode model organisms such as Caenorhabditis elegans and Pristionchus pacificus are powerful systems for studying the evolution of gene function at a mechanistic level. However, the identification of P. pacificus orthologs of candidate genes known from C. elegans is complicated by the discrepancy in the quality of gene annotations, a common problem in nematode and invertebrate genomics.

Results

Here, we combine comparative genomic screens for suspicious gene models with community-based curation to further improve the quality of gene annotations in P. pacificus. We extend previous curations of one-to-one orthologs to larger gene families and also orphan genes. Cross-species comparisons of protein lengths, screens for atypical domain combinations and species-specific orphan genes resulted in 4311 candidate genes that were subject to community-based curation. Corrections for 2946 gene models were implemented in a new version of the P. pacificus gene annotations. The new set of gene annotations contains 28,896 genes and has a single copy ortholog completeness level of 97.6%.

Conclusions

Our work demonstrates the effectiveness of comparative genomic screens to identify suspicious gene models and the scalability of community-based approaches to improve the quality of thousands of gene models. Similar community-based approaches can help to improve the quality of gene annotations in other invertebrate species, including parasitic nematodes.

Two new Species of Pristionchus (Nematoda: Diplogastridae) include the Gonochoristic Sister Species of P. fissidentatus

The genus Pristionchus (Kreis, 1932) consists of more than 30 soil nematode species that are often found in association with scarab beetles. Three major radiations have resulted in the "maupasi species group" in America, the "pacificus species group" in Asia, and the "lheritieri species group," which contains species from Europe and Asia. Phylogenetic analysis indicates that a group of three species, including the gonochorists P. elegans and P. bucculentus and the hermaphrodite P. fissidentatus, is basal to the above-mentioned radiations. Two novel species are described here: Pristionchus paulseni sp. n. from Taiwan and P. yamagatae sp. n. from Japan by means of morphology, morphometrics and genome-wide transcriptome sequence analysis. Previous phylotranscriptomic analysis of the complete Pristionchus genus recognized P. paulseni sp. n. as the sister species of P. fissidentatus, and thus its importance for macro-evolutionary studies. Specifically, the gonochorist P. paulseni sp. n. and the hermaphrodite P. fissidentatus form a species pair that is the sister group to all other described Pristionchus species. P. paulseni sp. n. has two distinct mouth forms, supporting the notion that the mouth dimorphism is ancestral in the genus Pristionchus.

The genus Pristionchus (Kreis, 1932) consists of more than 30 soil nematode species that are often found in association with scarab beetles. Three major radiations have resulted in the “maupasi species group” in America, the “pacificus species group” in Asia, and the “lheritieri species group,” which contains species from Europe and Asia. Phylogenetic analysis indicates that a group of three species, including the gonochorists P. elegans and P. bucculentus and the hermaphrodite P. fissidentatus, is basal to the above-mentioned radiations. Two novel species are described here: Pristionchus paulseni sp. n. from Taiwan and P. yamagatae sp. n. from Japan by means of morphology, morphometrics and genome-wide transcriptome sequence analysis. Previous phylotranscriptomic analysis of the complete Pristionchus genus recognized P. paulseni sp. n. as the sister species of P. fissidentatus, and thus its importance for macro-evolutionary studies. Specifically, the gonochorist P. paulseni sp. n. and the hermaphrodite P. fissidentatus form a species pair that is the sister group to all other described Pristionchus species. P. paulseni sp. n. has two distinct mouth forms, supporting the notion that the mouth dimorphism is ancestral in the genus Pristionchus.

Two New Species of Pristionchus (Nematoda: Diplogastridae) from Taiwan and the Definition of the pacificus Species-Complex Sensu Stricto

Pristionchus pacificus Sommer, Carta, Kim, and Sternberg, 1996 is an important model organism in evolutionary biology that aims to integrate developmental biology and evo-devo with population genetics and ecology. Functional studies in P. pacificus are supported by a well-established phylogenetic framework of around 30 species of the genus Pristionchus that have been described in the last decade based on their entomophilic and necromenic association with scarab beetles. Biogeographically, East Asia has emerged as a hotspot of Pristionchus speciation and recent samplings have therefore focused on Islands and mainland settings in East Asia. Here, we describe in a series of three publications the results of our sampling efforts in Taiwan, Japan, and Hongkong in 2016 and 2017. We describe a total of nine new species that cover different phylogenetic species-complexes of the Pristionchus genus. In this first publication, we describe two new species, Pristionchus sikae sp. n. and Pristionchus kurosawai sp. n. that are closely related to P. pacificus . Together with five previously described species they form the " pacificus species-complex sensu stricto" that is characterized by all species forming viable, but sterile F1 hybrids indicating reproductive isolation. P. sikae sp. n. and P. kurosawai sp. n. have a gonochorist mode of reproduction and they are described using morphology, morphometrics, mating experiments, and genome-wide sequence analysis. We discuss the extreme diversification in the pacificus species-complex sensu stricto in East Asia and its potential power to study speciation processes.

Samplings of Millipedes in Japan and Scarab Beetles in Hong Kong result in five new Species of Pristionchus (Nematoda: Diplogastridae)

The authors describe five new species of Pristionchus from Japan and Hongkong. Scarab beetle samplings in Hongkong identified P. hongkongensis sp. n. and P. neolucani sp. n., representing the first beetle-associated Pristionchus species from China. Surprisingly, samplings of millipedes in Japan revealed a previously unknown association of Pristionchus nematodes with these arthropods. Specifically, the authors found three previously known Pristionchus species, P. arcanus, P. entomophagus, and P. fukushimae on Japanese millipedes. In addition, the authors found three new Pristionchus species on millipedes, which are described as P. riukiariae sp. n., P. degawai sp. n., and P. laevicollis, sp. n., the latter of which was also found on stag beetles. These species are most closely related to P. maxplancki, P. japonicus, and P. quartusdecimus and belong to the pacificus species-complex. The authors describe all species based on morphology, morphometrics, and genome-wide sequence analysis. Mating experiments indicated that all species are reproductively isolated from each other and in contrast to the species of the "pacificus species-complex sensu stricto" they do not form F1 hybrids.

The authors describe five new species of Pristionchus from Japan and Hongkong. Scarab beetle samplings in Hongkong identified P. hongkongensis sp. n. and P. neolucani sp. n., representing the first beetle-associated Pristionchus species from China. Surprisingly, samplings of millipedes in Japan revealed a previously unknown association of Pristionchus nematodes with these arthropods. Specifically, the authors found three previously known Pristionchus species, P. arcanus, P. entomophagus, and P. fukushimae on Japanese millipedes. In addition, the authors found three new Pristionchus species on millipedes, which are described as P. riukiariae sp. n., P. degawai sp. n., and P. laevicollis, sp. n., the latter of which was also found on stag beetles. These species are most closely related to P. maxplancki, P. japonicus, and P. quartusdecimus and belong to the pacificus species-complex. The authors describe all species based on morphology, morphometrics, and genome-wide sequence analysis. Mating experiments indicated that all species are reproductively isolated from each other and in contrast to the species of the “pacificus species-complex sensu stricto” they do not form F1 hybrids.

Large-scale diversification without genetic isolation in nematode symbionts of figs

Diversification is commonly understood to be the divergence of phenotypes accompanying that of lineages. In contrast, alternative phenotypes arising from a single genotype are almost exclusively limited to dimorphism in nature. We report a remarkable case of macroevolutionary-scale diversification without genetic divergence. Upon colonizing the island-like microecosystem of individual figs, symbiotic nematodes of the genus Pristionchus accumulated a polyphenism with up to five discrete adult morphotypes per species. By integrating laboratory and field experiments with extensive genotyping of individuals, including the analysis of 49 genomes from a single species, we show that rapid filling of potential ecological niches is possible without diversifying selection on genotypes. This uncoupling of morphological diversification and speciation in fig-associated nematodes has resulted from a remarkable expansion of discontinuous developmental plasticity.

Gap junctions composed of connexins 41.8 and 39.4 are essential for colour pattern formation in zebrafish

Interactions between all three pigment cell types are required to form the stripe pattern of adult zebrafish (Danio rerio), but their molecular nature is poorly understood. Mutations in leopard (leo), encoding Connexin 41.8 (Cx41.8), a gap junction subunit, cause a phenotypic series of spotted patterns. A new dominant allele, leo^tK3, leads to a complete loss of the pattern, suggesting a dominant negative impact on another component of gap junctions. In a genetic screen, we identified this component as Cx39.4 (luchs). Loss-of-function alleles demonstrate that luchs is required for stripe formation in zebrafish; however, the fins are almost not affected. Double mutants and chimeras, which show that leo and luchs are only required in xanthophores and melanophores, but not in iridophores, suggest that both connexins form heteromeric gap junctions. The phenotypes indicate that these promote homotypic interactions between melanophores and xanthophores, respectively, and those cells instruct the patterning of the iridophores.

DOI:http://dx.doi.org/10.7554/eLife.05125.001

The colour patterns that mark an animal's skin, hair, or feathers—called the pigmentation pattern—can be very important for its survival and fitness, helping it to hide from predators or to attract a mate. As a result, there is considerable interest in understanding how genes, proteins, and cells work together to produce the many different pigmentation patterns that exist in the animal world.

Adult zebrafish have a characteristic pigmentation pattern of horizontal dark and light stripes on their bodies and fins. There are three types of pigment cell that create this pattern. Xanthophores and iridophores are found all over the body, and the dark stripes also contain melanophore cells. The silvery, reflective iridophores are the first of the cells to populate the skin, giving rise to the first light stripe. They then form a dense network of cells that breaks up to form the darker stripes. However, iridophores are not required to form stripes in the fins, suggesting that patterning occurs differently in the fins and the body.

Mutations to a gene called leopard, or leo for short, cause spots to form on the skin of the zebrafish in place of the usual stripes. This gene encodes a member of the connexin family of proteins, which form channels in the membranes that surround cells. These channels—known as gap junctions—allow neighbouring cells to communicate with each other. Each gap junction is made up of two half channels, with one half coming from each neighbouring cells. If the two half channels are identical, the gap junction is known as ‘homomeric’; ‘heteromeric’ gap junctions are made from two different half channels, each consisting of a different connexin protein. The connexin encoded by leo is required for both types of gap junction to form between melanophores and xanthophores.

Irion et al. discovered a new mutation to the leo gene that completely disrupts the patterning of the zebrafish. A technique called a genetic screen revealed that the same patterning defects are also seen in the body of zebrafish with mutations to another gene called luchs, which encodes a different connexin protein to the one produced by leo. However, the fins of zebrafish with mutant versions of luchs remain striped.

The findings of Irion et al. suggest that heteromeric gap junctions formed from the connexins produced by leo and luchs are important for xanthophores and melanophores to communicate with each other and so form the stripy patterning seen on the body of the zebrafish. The signals transmitted through the gap junctions may also make the iridophores adopt the looser arrangement that is required for the dark stripes to form. As a next step, it will be important to identify the signals that pass through these gap junctions that allow the cells to communicate with their neighbours and establish the pigmentation pattern.

DOI:http://dx.doi.org/10.7554/eLife.05125.002

[In situ analysis of pathomechanisms of human intervertebral disc degeneration]

BACKGROUND

Low back pain is one of the major causes of pain and disability in the western world, with a constantly rising life-time prevalence of approximately 60-85 %. Degeneration of the intervertebral disc is believed to be a major cause of low back pain.

MATERIALS AND METHODS

Semiquantitative macroscopic and microscopic changes of the intervertebral disc were assessed and classified. Furthermore additional methods, such as immunohistochemistry, in situ hybridization and in situ zymography were used to analyze phenotypic cellular and matrix changes.

RESULTS

We have developed and tested a practicable, valid and reliable histological classification system for lumbar discs which can serve as a morphological reference framework to allow more sophisticated molecular biological studies on the pathogenesis of ageing and degeneration of discs. Secondly, we were able to demonstrate that intrinsic (genetic) and extrinsic (e.g. overweight) factors have a profound effect on the process of disc degeneration. Cells with a notochord-like phenotype are present in a considerable fraction of adult lumbar intervertebral discs. The presence of these cells is associated with distinct features of (early) age-related disc degeneration. During the process of disc degeneration, the intervertebral disc shows a progressive and significant reduction in height due to tissue resorption. This matrix loss is related to an imbalance between matrix synthesis and degradation. During this process an inflammatory reaction takes place and resident disc cells are causatively involved.

CONCLUSIONS

In summary, disc degeneration is a multifactorial disease with a strong intrinsic (hereditary) and extrinsic (e.g. mechanical factors) background. The process starts as early as in the second decade of life and shows high interindividual differences. The loss of regenerative capacity in the intervertebral disc is probably related to the loss of stem cells, e.g. notochord-like cells. Resident disc cells are involved in the inflammatory reaction with increased matrix degradation, resorption and reduced matrix synthesis.

Endothelin signalling in iridophore development and stripe pattern formation of zebrafish

Colour patterns of adult fish are composed of several different types of pigment cells distributing in the skin during juvenile development. The zebrafish, Danio rerio, displays a striking pattern of dark stripes of melanophores interspersed with light stripes of xanthophores. A third cell type, silvery iridophores, contributes to both stripes and plays a crucial role in adult pigment pattern formation. Several mutants deficient in iridophore development display similar adult phenotypes with reduced numbers of melanophores and defects in stripe formation. This indicates a supporting role of iridophores for melanophore development and maintenance. One of these mutants, rose (rse), encodes the Endothelin receptor b1a. Here we describe a new mutant in zebrafish, karneol (kar), which has a phenotype similar to weak alleles of rse with a reduction in iridophore numbers and defects of adult pigment patterning. We show that, unlike rse, kar is not required in iridophores. The gene defective in the kar mutant codes for an endothelin-converting enzyme, Ece2, which activates endothelin ligands by proteolytic cleavage. By morpholino-mediated knockdown, we identify Endothelin 3b (Edn3b) as the ligand for endothelin receptor signalling in larval iridophores. Thus, Endothelin signalling is involved in iridophore development, proliferation and stripe morphogenesis in larvae as well as adult zebrafish. In mammals the pathway is required for melanocyte development; therefore, our results indicate a previously unrecognized close evolutionary relationship between iridophores in zebrafish and melanocytes in mammals.

[Unilateral maxillary sinusitis: a cavernous haemangioma with bone destruction]

Haemangioma originating in the paranasal sinuses are a rare entity. In the case of unilateral sinusitis the differential diagnosis should include tumors. The following case of a 30-year-old female patient with a therapy-resistant sinusitis showed bone destruction and a maxillary shadow on computed tomography. The histological exam resulted in a cavernous haemangioma.

Age-related changes in human cervical, thoracal and lumbar intervertebral disc exhibit a strong intra-individual correlation

INTRODUCTION

Intervertebral disc (IVD) degeneration is characterized as a multifactorial disease, in which the hereditary background is thought to be of high importance. Accordingly, one would expect all spinal levels (lumbar/cervical/thoracal) to be affected by above-average disc degeneration in genetically predisposed individuals. The aim of this study, therefore, was to analyze the amount of degenerative changes in different spine levels in humans from different ages.

MATERIALS AND METHODS

In detail, the presence, localization and abundance of histomorphological changes in the annulus fibrosus (AF) and nucleus pulposus (NP) in the cervical (C5/C6), thoracic (T2/T3) and lumbar (L2/L3) spine were investigated in complete autopsy IVD specimens (47 individuals) covering a complete age range (0-95 years).

RESULTS

Results indicate that the highest degree of histo-degenerative changes were observed in the NP in all spine levels and showed an age-related expression pattern. With regard to the different spine levels, lumbar disc specimen showed significantly more degenerative changes compared to cervical and thoracic discs, whereas no statistical difference was observed between cervical and thoracic discs. In summary, highest grades of degeneration were observed in lumbar discs (especially in the NP). Intra-individual correlations between the degeneration score in the different levels showed a significant individual concordance.

CONCLUSIONS

The intra-individual correlation of degenerative changes in all three examined spine regions further supports the notion that individual, i.e. genetic factors are strong predisposing factor for the development of age-related disc alterations.

[Reduced bone density and bone pain :osteomalacia with hypophospatemia and hypophosphaturia]

Two patients aged 24 and 64 years presented at our hospital with similar symptoms including bone pain and muscle weakness. Basic laboratory tests and urinary diagnostics, bone densitometry and bone histology revealed severe osteomalacia with renal phosphate wasting. After the exclusion of other causes an extensive tumor search was performed due to suspected tumor-induced osteomalacia. In one patient a mesenchymal tumor was found in the thigh and completely resected. After surgery the patient showed a rapid recovery from osteomalacia. Because the search was unsuccessful in the other patient phosphorus supplementation in combination with calcitriol was started. Despite continuing renal phosphate wasting a significant increase in bone mineral density was observed.

Intraductal carcinoma is the precursor of carcinoma ex pleomorphic adenoma and is often associated with dysfunctional p53

AIMS

Although intraductal carcinoma has been demonstrated in intracapsular carcinoma ex pleomorphic adenoma (CEPA), the morphological and genetic stages of transformation of pleomorphic adenoma (PA) to CEPA are not fully understood. The aim of this study was to investigate the morphology of intracapsular CEPA.

METHODS AND RESULTS

The largest series of intracapsular CEPA studied was subject to immunohistochemical double-staining to detect p53 protein and cellular proliferation in different types of cell combined with mutational analysis of the p53 gene in laser-microdissected material. Intraductal carcinoma with high-grade cellular atypia and frequent accumulation of p53 protein was found in 15/19 cases. Purely intraductal carcinoma was found in eight cases. Mutation of p53 was found in 7/19 cases, of which it was found in intraductal carcinoma in 5/15 cases.

CONCLUSIONS

The frequent demonstration of intraductal carcinoma indicates that this preinvasive lesion is likely to be a constant feature in the malignant transformation of PA to CEPA. It appears to be a feature of CEPA developing from both primary and recurrent PA. The combined immunohistochemical and genetic data show that 14/19 cases of CEPA and 11/15 cases with intraductal carcinoma showed genetic or morphological evidence of dysfunctional p53, indicating that this is an early event in malignant transformation.

Large-scale mapping of mutations affecting zebrafish development

Background

Large-scale mutagenesis screens in the zebrafish employing the mutagen ENU have isolated several hundred mutant loci that represent putative developmental control genes. In order to realize the potential of such screens, systematic genetic mapping of the mutations is necessary. Here we report on a large-scale effort to map the mutations generated in mutagenesis screening at the Max Planck Institute for Developmental Biology by genome scanning with microsatellite markers.

Results

We have selected a set of microsatellite markers and developed methods and scoring criteria suitable for efficient, high-throughput genome scanning. We have used these methods to successfully obtain a rough map position for 319 mutant loci from the Tübingen I mutagenesis screen and subsequent screening of the mutant collection. For 277 of these the corresponding gene is not yet identified. Mapping was successful for 80 % of the tested loci. By comparing 21 mutation and gene positions of cloned mutations we have validated the correctness of our linkage group assignments and estimated the standard error of our map positions to be approximately 6 cM.

Conclusion

By obtaining rough map positions for over 300 zebrafish loci with developmental phenotypes, we have generated a dataset that will be useful not only for cloning of the affected genes, but also to suggest allelism of mutations with similar phenotypes that will be identified in future screens. Furthermore this work validates the usefulness of our methodology for rapid, systematic and inexpensive microsatellite mapping of zebrafish mutations.

[New bone formation by extracorporeal shock waves. Dependence of induction on energy flux density]

BACKGROUND

The purpose of this study was to test the hypothesis that shock waves can induce new bone formation even without cortical fractures and periosteal detachment as suggested in the literature.

METHODS

Extracorporeal shock waves with energy flux densities between 0 mJ/mm(2) (sham treatment) and 1.2 mJ/mm(2) were applied in vivo to the distal femoral region of rabbits (1500 pulses at 1 Hz frequency each). Oxytetracycline was injected on days 5-9 and the animals were sacrificed on day 10. Sections of both femora of all animals were investigated with broadband fluorescence microscopy and contact microradiography for new periosteal and endosteal bone, periosteal detachment, cortical fractures, and trabecular bone with callus.

RESULTS

Shock waves with energy flux densities of 0.9 mJ/mm(2) and 1.2 mJ/mm(2) resulted in new periosteal bone formation in the presence of cortical fractures and periosteal detachment. After application of shock waves with energy flux density of 0.5 mJ/mm(2), clearly detectable signs of new periosteal bone formation were observed without cortical fractures or periosteal detachment.

CONCLUSIONS

The results of this study challenge the current view in the literature that the creation of cortical fractures and periosteal detachment are prerequisites for new bone formation mediated by extracorporeal shock waves.

iguana encodes a novel zinc-finger protein with coiled-coil domains essential for Hedgehog signal transduction in the zebrafish embryo

Signaling by lipid-modified secreted glycoproteins of the Hedgehog family play fundamental roles during pattern formation in animal development and in humans; dysfunction of Hedgehog pathway components is frequently associated with a variety of congenital abnormalities and cancer. Transcriptional regulation of Hedgehog target genes is mediated by members of the Gli zinc-finger transcription factors. The relative nuclear concentrations of Gli activator (Gli(act)) and repressor (Gli(rep)) forms, together with their nucleocytoplasmic trafficking, appear to be critical determinants for target gene expression. Whereas such stringent controls of Gli activity are critical in ensuring appropriate levels of pathway activation, the mechanisms by which these processes are regulated remain inadequately understood. Here, using genetic analysis, we show that the zebrafish iguana gene product acts downstream of the Smoothened protein to modulate Gli activity in the somites of the developing embryo. Positional cloning reveals that iguana encodes the zebrafish ortholog of Dzip1, a novel zinc-finger/coiled-coil domain protein that we show can shuttle between the cytoplasm and nucleus in a manner correlated with Hedgehog pathway activity.

2002 SSE Award Competition in Basic Science: expression of major matrix metalloproteinases is associated with intervertebral disc degradation and resorption

During the process of degeneration, the intervertebral disc (IVD) shows a progressive and significant reduction in height due to tissue resorption. Intradiscal clefts and tears are major hallmarks of disc degeneration. Matrix-degrading enzymes such as matrix metalloproteinases (MMPs) are assumed to play a pivotal role in disc tissue degradation and resorption. The objective of this study was therefore to investigate the potential role of MMPs in extracellular matrix degradation leading to disc degeneration. This study was conducted on 30 formalin-fixed and EDTA-decalcified complete cross-sections of lumbar IVDs from cadavers of individuals aged between 0 and 86 years. Tissue sections were used for the immunolocalization of MMPs-1, -2, -3 and -9. The number of labeled cells was assessed by morphometric analyses, and was statistically correlated with the formation of clefts and tears, cellular proliferation, granular matrix changes and mucous degeneration. Furthermore, 30 disc specimens obtained during spinal surgery were used for in situ hybridization of MMP-2 and -3-mRNA. In addition, the enzymatic gelatinolytic activity was determined by in situ zymography in autopsy material. Immunohistochemistry showed the intradiscal expression of all four MMPs, which was confirmed by in situ hybridization, providing clear evidence for the synthesis of the enzymes within nucleus pulposus and annulus fibrosus cells. Gelatinolytic enzymatic activity was verified by in situ zymography. IVDs from infants and young adolescents remained almost completely unlabeled for all MMPs tested, while more MMPs-1 and -3 were seen in disc cells of younger adults than in those of a more advanced age; MMP-2 remained unchanged over the adult age periods, and MMP-9 was expressed in only relatively few cells. This pattern significantly correlated with the occurrence of clefts and tears. This correlation was strongest for MMP-1 ( P<0.0001), MMP-2 ( P<0.0017) and MMP-3 ( P<0.0005) in the nucleus, and MMP-1 ( P<0.0001) and MMP-2 ( P<0.038) in the annulus. In parallel, the proliferation of disc cells and matrix degeneration (granular changes and mucous degeneration) were related to MMP expression. Likewise, enzymatic activity was seen in association with cleft formation. Our data suggest that major MMPs play an important role in the degradation of the IVD. This is evidenced by the high correlation of MMP expression with the formation of clefts and tears. These findings implicate a leading function for MMPs in IVD degeneration resulting in the loss of normal disc function, eventually leading to low-back pain.

Influence of extracorporeal shock-wave application on normal bone in an animal model in vivo. Scintigraphy, MRI and histopathology

There is little information about the effects of extracorporeal shock-wave application (ESWA) on normal bone physiology. We have therefore investigated the effects of ESWA on intact distal rabbit femora in vivo. The animals received 1500 shock-wave pulses each of different energy flux densities (EFD) on either the left or right femur or remained untreated. The effects were studied by bone scintigraphy, MRI and histopathological examination. Ten days after ESWA (0.5 mJ/mm2 and 0.9 mJ/mm2 EFD), local blood flow and bone metabolism were decreased, but were increased 28 days after ESWA (0.9 mJ/mm2). One day after ESWA with 0.9 mJ/mm2 EFD but not with 0.5 mJ/mm2, there were signs of soft-tissue oedema, epiperiosteal fluid and bone-marrow oedema on MRI. In addition, deposits of haemosiderin were found epiperiosteally and within the marrow cavity ten days after ESWA. We conclude that ESWA with both 0.5 mJ/mm2 and 0.9 mJ/mm2 EFD affected the normal bone physiology in the distal rabbit femur. Considerable damaging side-effects were observed with 0.9 mJ/mm2 EFD on periosteal soft tissue and tissue within the bone-marrow cavity.

Influence of extracorporeal shock-wave application on normal bone in an animal model in vivo

There is little information about the effects of extracorporeal shock-wave about application the effects (ESWA) of on normal bone physiology. We have therefore investigated the effects of ESWA on intact distal rabbit femora in vivo. The animals received 1500 shock-wave pulses each of different energy flux densities (EFD) on either the left or right femur or remained untreated. The effects were studied by bone scintigraphy, MRI and histopathological examination.

Ten days after ESWA (0.5 mJ/mm2 and 0.9 mJ/mm2 EFD), local blood flow and bone metabolism were decreased, but were increased 28 days after ESWA (0.9 mJ/mm2). One day after ESWA with 0.9 mJ/mm2 EFD but not with 0.5 mJ/mm2, there were signs of soft-tissue oedema, epiperiosteal fluid and bone-marrow oedema on MRI. In addition, deposits of haemosiderin were found epiperiosteally and within the marrow cavity ten days after ESWA.

We conclude that ESWA with both 0.5 mJ/mm2 and 0.9 mJ/mm2 EFD affected the normal bone physiology in the distal rabbit femur. Considerable damaging side-effects were observed with 0.9 mJ/mm2 EFD on periosteal soft tissue and tissue within the bone-marrow cavity.

Peptide-based analysis of amino acid sequences important to the biological activity of eosinophil granule major basic protein

Synthetic peptides corresponding to amino acid sequences in eosinophil granule major basic protein (MBP) were evaluated for cytotoxic activity toward K562 cells and for ability to stimulate basophil mediator release. Results obtained using 14 peptides spanning the 117-amino acid sequence of MBP in overlapping fashion indicated that the activities mapped to peptide sequences near the amino and carboxy termini of MBP. The activity of these regions was confirmed using two peptides corresponding to MBP residues 18-45 and 89-117. A 20-h incubation with 5 microM peptide 18-45 or peptide 89-117 caused approximately the same levels (>60%) of cytotoxicity in K562 cells as 5 microM MBP. Similarly, a 30-min incubation with peptides 18-44 and 89-117 stimulated basophil histamine release in a concentration-dependent manner over the range of 5-20 microM. The level of release stimulated by 20 microM peptide 89-117 approached that stimulated by 2 microM MBP. A 20 microM concentration of peptide 89-117 also stimulated leukotriene C4 (LTC4) production by the basophils. Neither peptide 18-45 nor peptide 89-117 was cytotoxic for basophils under the experimental conditions for histamine and LTC4 release, as determined by 51Cr release. These results indicate that two MBP peptide sequences, including one (89-117) that contains a unique carbohydrate-binding region, share the biologic activities of MBP.

In situ compressive stiffness, biochemical composition, and structural integrity of articular cartilage of the human knee joint

OBJECTIVE

Reduction of compressive stiffness of articular cartilage has been reported as one of the first signs of cartilage degeneration. For the measurement of in situ compressive stiffness, a hand-held indentation probe has recently been developed and baseline data for macroscopically normal knee joint cartilage were provided. However, the histological stage of degeneration of the measured cartilage was not known. The purpose of this study was to investigate whether there is a relationship between the in situ measured compressive stiffness, the histological stage of degeneration, and the biochemical composition of articular cartilage.

DESIGN

Instantaneous compressive stiffness was measured for the articular cartilage of 24 human cadaver knees. Additionally, biochemical composition (total proteoglycan and collagen content) and histological appearance (according to the Mankin score) were assessed for each measurement location.

RESULTS

Despite visually normal surfaces, various histological signs of degeneration were present. A high correlation between Mankin score and cartilage stiffness was observed for the lateral patellar groove (R(2)=0.81), the medial (R(2)=0.83) and the lateral femoral condyle (R(2)=0.71), whereas a moderate correlation was found for the medial patellar groove (R(2)=0.44). No correlation was observed between biochemical composition and cartilage compressive stiffness.

CONCLUSIONS

Our results are in agreement with others and show that the instantaneous compressive stiffness is primarily dependent on the integrity of the extracellular matrix, and not on the content of the major cartilage constituents. The high correlation between stiffness and Mankin score in mild osteoarthrosis suggests that the stage of cartilage degeneration can be assessed quantitatively with the hand-held indentation probe. Moderate and severe case of osteoarthrosis remains to be investigated.

Impaired tensile strength after shock-wave application in an animal model of tendon calcification

Extracorporeal shock-wave application facilitates dissolution of rotator cuff calcifications. Therefore, disappearance or disintegration of tendon calcifications by shock waves might be appropriate for any kind of tendon calcification. Here, shock waves with various energy flux densities were applied to the mineralized medial gastrocnemius tendon of turkeys as an animal model. After application of shock waves in vivo, with energy flux density of 0.6 mJ/mm(2), histologic examination and microradiography did not show dissolution or disintegration of tendon calcifications. After shock-wave application in vitro, even for energy flux density of 1.2 mJ/mm(2) neither dissolution nor disintegration of tendon calcifications were observed. Biomechanical testing revealed significant impairment of tensile strength following shock-wave application in vitro, with energy flux density of 1.2 mJ/mm(2), but not with 0.6 mJ/mm(2). These results are important for considerations of clinical extracorporeal shock-wave application on tendon calcifications, as well as on tendon ossifications.

Quantification of laser-induced cartilage injury by confocal microscopy in an ex vivo model

BACKGROUND

The application of lasers in orthopaedic surgery is increasing. However, some investigators have reported that osteonecrosis may occur after laser meniscectomy. The objective of the present study was to evaluate the effect of laser wavelength and energy on cartilage injury in an ex vivo model.

METHODS

Fresh bovine articular cartilage was exposed to either holmium:yttrium-aluminum-garnet (Ho:YAG) or erbium:YAG-laser (Er:YAG) irradiation. Both lasers were operated in a free-running mode and at a pulse-repetition rate of 8 Hz. The effect of laser treatment at several energy levels (Er:YAG at 100 and 150 mJ and Ho:YAG at 500 and 800 mJ) was examined. For each light source and energy level, ten cartilage samples were assessed by conventional histological analysis and by confocal microscopy. Thermal damage was assessed by determining cell viability.

RESULTS

The extent of thermal damage demonstrated by confocal microscopy was much greater than that demonstrated by histological analysis. The extent of thermal injury after Ho:YAG-laser irradiation was much greater than that after Er:YAG-laser irradiation, which was associated with almost no damage. In addition, the ablation depth was greater after treatment with the Er:YAG laser than after treatment with the Ho:YAG laser.

CONCLUSIONS

In the present study, histological analysis underestimated thermal damage after laser irradiation. In addition, our findings highlighted problems associated with use of high-power settings of Ho:YAG lasers during arthroscopic surgery.

Foreign-body reaction to silastic burr-hole covers with seroma formation: case report and review of the literature

Because silastic material is one of the most commonly used biomaterials in modern medicine, the biocompatibility of these implants is still a source of long standing controversy. Though several studies have established silastic material as biologically inert, numerous authors have repeatedly described characteristic pathological tissue responses to silicone and its elastomeres. We report a case of foreign-body reaction to silastic burr-hole cover with successive formation of a seroma following resection of an olfactory groove meningioma. Within 30 days postoperatively, the patient developed a marked bulge in the glabbelar region. Histopathological examination revealed a seroma-like lesion obviously caused by a chronic inflammatory allergic reaction to the silastic burr-hole cover. Although the silicone-induced tissue damage clinically shows a wide variability and a conclusive model of pathogenesis is presently not available, the histopathological findings in some patients, in the form of granulomatous lesions and inflammatory cell response, might partly be due to an immunological reaction. Such a reaction has been previously described both clinically and experimentally, as detected in our patient. In addition, a review of the literature is given.

A radiation hybrid map of the zebrafish genome

Recent large-scale mutagenesis screens have made the zebrafish the first vertebrate organism to allow a forward genetic approach to the discovery of developmental control genes. Mutations can be cloned positionally, or placed on a simple sequence length polymorphism (SSLP) map to match them with mapped candidate genes and expressed sequence tags (ESTs). To facilitate the mapping of candidate genes and to increase the density of markers available for positional cloning, we have created a radiation hybrid (RH) map of the zebrafish genome. This technique is based on somatic cell hybrid lines produced by fusion of lethally irradiated cells of the species of interest with a rodent cell line. Random fragments of the donor chromosomes are integrated into recipient chromosomes or retained as separate minichromosomes. The radiation-induced breakpoints can be used for mapping in a manner analogous to genetic mapping, but at higher resolution and without a need for polymorphism. Genome-wide maps exist for the human, based on three RH panels of different resolutions, as well as for the dog, rat and mouse. For our map of the zebrafish genome, we used an existing RH panel and 1,451 sequence tagged site (STS) markers, including SSLPs, cloned candidate genes and ESTs. Of these, 1,275 (87.9%) have significant linkage to at least one other marker. The fraction of ESTs with significant linkage, which can be used as an estimate of map coverage, is 81.9%. We found the average marker retention frequency to be 18.4%. One cR3000 is equivalent to 61 kb, resulting in a potential resolution of approximately 350 kb.

Drug targeting and metabolic investigations of cryoprepared tumor cells with analytical electron energy loss spectroscopy

Analytical electron microscopy is an ideal tool for holistic data acquisition on biological systems. The use of analytical electron microscopy for both, the investigation of micropharmacokinetic problems and metabolic studies, is becoming more and more important. Depending on the mode of investigation, it is possible to localize drugs and xenobiotics precisely in situ under optical control or to quantify their uptake and distribution in the corresponding target cells without disintegrating the cell or tissue material. In this paper, we present instructive examples for the application of analytical electron energy loss spectroscopy in transmission electron microscopy in order to investigate the cellular uptake and distribution of cisplatin and cyclophosphamide and the metabolic changes induced by an alteration in the extracellular calcium concentration in a holistic manner.

The use of neuromuscular blocking drugs in the intensive care unit: a US perspective

Surprisingly little is known about the use of neuromuscular blockers (NMBs) in intensive care units (ICUs) in the USA. Recently, Klessig et al. surveyed anesthesiologists/intensivists in the USA and found that the 55% who responded used NMBs in the ICU in an average of 10 patients per ICU per month. Anxiolytics and analgesics were administered concomitantly with NMBs, but a majority of respondents did not use electrophysiologic measures of the degree of blockade. Another survey of predominantly medical ICUs also demonstrated widespread use of NMBs, but internists did not use sedation/analgesia as frequently as anesthesiologists for patients receiving NMBs, and infrequently monitored the degree of neuromuscular blockade. Because these were retrospective surveys, we decided to monitor prospectively the use of NMBs in our ICUs. The use of NMBs was ascertained by daily review of pharmacy records and, when use was documented, the patients' hospital records were reviewed. Where information was missing or not found, attending physicians were interviewed. On average, one patient per month per ICU received NMBs. Approximately 5% of neonatal and pediatric, and 1% of adult, ICU patients received NMBs. Eighty-three percent of patients received NMBs to facilitate mechanical ventilation, and mortality was high (51%) in those critically ill patients. More than half the patients were treated for < or = 24 h, the remainder for 2 days to > 3 weeks. Twitch monitors were used for monitoring the degree of neuromuscular blockade in adult patients, and all patients received sedatives/analgesics. We estimated that the risk of clinically significant, prolonged neuromuscular blockade following the discontinuation of NMBs was 5% per year.(ABSTRACT TRUNCATED AT 250 WORDS)

Increased prostaglandin PGE2 and 6-keto-PGF1 alpha immunoactivity in incubates of gastric mucosa and forestomach of nephrectomized rats

Prostaglandin E2 (PGE2)- and 6-keto-PGF1 alpha-like immunoactivity was measured in incubates of forestomach and gastric corpus mucosa in (a) unoperated rats, (b) rats with sham-operation of the kidneys and (c) rats with bilateral nephrectomy. In addition the mean ulcer area in the forestomach and gastric mucosa was assayed in all three groups of rats. The PGE2- and 6-keto-PGF1 alpha-like immunoactivity in gastric mucosa incubates and 6-keto-PGF1 alpha in the forestomach incubates was almost the same in unoperated and sham-operated rats. Increased 6-keto-PGF1 alpha in the forestomach and of PGE2 and 6-keto-PGF1 alpha in the gastric mucosa was found in rats with bilateral nephrectomy before gastric lesions were seen. A higher mean ulcer area occurred in the forestomach and gastric mucosa 24-48 h after bilateral nephrectomy. We conclude, that the increased PGE2- and 6-keto-PGF1 alpha production by the gastric mucosa and forestomach was associated with the loss of normal renal tissue function. Despite the protection of PGE2 and PGI2 by gastric tissue, gastric lesions nevertheless occur in acute uraemic rats.

Gastric mucosal PGE2 levels in gastric non-ulcer and ulcer patients with chronic renal failure or without renal diseases and in healthy subjects

PGE2-like immunoactivity in mucosal specimens from gastric corpus and antrum was measured in individuals with chronic uremia or without renal diseases in absence or presence of gastric ulcerations and in healthy subjects. Regardless the group of patients, compared to normal mucosa, a significant decrease in PGE2-like immunoactivity (50-70%) was found in mucosa from atrophic, but not from superficial gastritis. Whenever patients of the control group or patients with renal diseases suffered from ulcers, PGE2-like immunoactivity, compared to nonulcer subjects, revealed a decrease of about 60-70% in the nonulcerated mucosa. Compared to nonulcerated mucosa, the tissue of the ulcer rim in all patients with gastric ulcer showed a relative increase in PGE2-like immunoactivity, eg, PGE2-like immunoactivity was twice as high in tissue from the ulcer rim. The output of PGE2-like immunoactivity into the gastric juice of subjects without renal diseases was comparable to that found in patients with chronic uremia in both basal and pentagastrin-stimulated conditions. We therefore conclude that gastric mucosal formation is probably not influenced by chronic uremia.

Gastric mucosal prostaglandin E2 levels in gastric non-ulcer and ulcer patients with chronic renal failure or without renal disease, and in healthy subjects

Investigations were carried out as to whether a disturbance in the formation of cytoprotective prostaglandin (PG) E2 in gastric mucosa is implicated in chronic renal failure. PGE2-like immunoactivity in gastric mucosal specimens was measured in individuals with chronic renal failure (creatine clearance less than 10 ml/min), in individuals without any renal disease, presenting either gastric ulceration or not, as well as in healthy subjects. Regardless of the group of patients, compared to normal mucosa a significant decrease in PGE2-like immunoactivity (about 50-70%) was found in mucosa from atrophic gastritis but not from superficial gastritis. Whenever patients of the control group or patients with kidney disease suffered from ulcers, PGE2-like immunoactivity showed a decrease of about 60-70% in the non-ulcerated mucosa compared to that of non-ulcer subjects. Moreover, ulcer patients showed the same frequency of gastritis and similar mucosal PGE2-like immunoactivity in their non-ulcerated mucosa. Furthermore, compared to the tissue from the ulcer edge, independent of the presence of renal disease, a relative deficiency of PGE2-like immunoactivity of about 50-60% was detected in the non-ulcerated mucosa of ulcer patients. We therefore conclude that chronic renal failure probably has no impact on PGE2 formation in the gastric mucosa. All told, relative mucosal PGE2 deficiency in gastric ulcer disease seems not to be correlated with chronic renal failure.

Gastric mucosal prostaglandin E2 levels in cirrhosis and portal hypertension

Prostaglandin E2 (PGE2) tissue levels were measured, using radioimmunoassay, in specimens from the gastric antral mucosa in (a) healthy subjects, (b) patients without liver diseases in the absence or presence of gastric ulcers, and (c) patients with alcoholic cirrhosis in the absence or presence of gastric ulcers. These groups were divided further into subgroups with or without portal hypertension. PGE2 tissue levels in subjects without liver diseases were not significantly different from those of cirrhotic patients without portal hypertension. However, in cirrhotic patients with portal hypertension, the PGE2 content was significantly lower, especially in the presence of congestion in the mucosa (about 70-80%). When a gastric antral ulcer was present, a further statistically significant decrease of the PGE2 levels was observed. It was concluded that a decrease in the PGE2 tissue levels in the gastric mucosa of cirrhotic patients is related to the presence of portal hypertension. Congestion in the mucosa, as a pathogenetically relevant factor for mucosal PGE2 deficiency, may play a role.

Clinical trials of WR-2721 and cis-platinum

WR-2721 is an aminothiol compound; in the animal model it protects against the nephrotoxicity, neurotoxicity, and hematologic toxicity of cis-platinum. We initiated Phase I trials of WR-2721 and cis-platinum to determine toxicity when WR-2721 was given prior to escalating doses of cis-platinum. With mannitol diuresis and WR-2721, transient nephrotoxicity occurred in 9 of 30 (27%) patients treated with cis-platinum 150 mg/m2 and 7% of patients given with cis-platinum 120 mg/m2. Bone marrow suppression was mild and infrequent. Mild to moderate peripheral neuropathies occurred in 26% of patients courses following a mean cumulative cis-platinum dose of 725 mg/m2. Objective partial responses were observed in 53 of 118 (45%) patients with measurable disease. Antitumor responses were observed in 25 of 53 patients with metastatic melanoma, 12 of 22 patients with locally recurrent or metastatic head and neck cancer, and 7 of 13 patients with metastatic breast cancer refractory to conventional chemotherapy. Controlled studies of WR-2721 and cis-platinum will be performed in the Eastern Cooperative Oncology Group in these disease sites to better define the activity of this regimen and its toxicity.

Enhanced calcitonin secretion in the rat after parathyroidectomy and during chronic calcium deprivation

The thyroidal content of calcitonin (CT) and the serum calcitonin responses to acute hypercalcaemia were studied in female rats during chronic hypocalcaemia induced by parathyroidectomy (PTX), a low calcium (Ca) diet, or both. The thyroidal CT content of the PTX animals 50 days after surgery was twice that of intact rats. An acute intraperitoneal (i.p.) calcium load on day 50 after PTX resulted in an increase in serum CT twice as large as that observed in control animals. Reversal of the chronic hypocalcaemia with 1,25(OH)2D3 resulted in a reduction in thyroidal CT as well as a depression of the calcium-induced CT response. In each case the values were similar to those observed in normocalcaemic controls. A low calcium diet increased the thyroidal CT content in intact rats and induced a further increase in PTX rats. The CT response to an acute Ca load was exaggerated by a low calcium diet in intact as well as in PTX rats. These results suggest that in the rat chronic hypocalcaemia enhances CT storage and secretion.

WR-2721 and high-dose cisplatin: an active combination in the treatment of metastatic melanoma

Cisplatin, alone or in combination with other chemotherapeutic agents, is relatively inactive against metastatic melanoma. Prior trials have demonstrated partial response (PR) rates of less than 10% with cisplatin alone. WR-2721 is an organic thiophosphate compound, which in the animal model, selectively protects normal tissues against the toxicity of cisplatin chemotherapy. During the course of a phase I trial of WR-2721 and cisplatin, objective PRs were noted in patients with far advanced metastatic melanoma. These observations led us to perform a phase II trial of WR-2721 and cisplatin. Thirty-six patients received 128 courses of WR-2721 before cisplatin (60 to 150 mg/m2). All patients had progressive disease before treatment. Objective PRs were observed in 19 of 36 evaluable patients (53%). Three additional patients had minor responses (MRs). PRs occurred in 53% of patients with prior chemotherapy (ten of 19). Sites of responding metastases were subcutaneous disease (15 of 19 patients), lymph nodes (16 of 21 patients), lung (four of ten patients), and liver (eight of 17 patients). The median duration of response was 4 months, with a mean of 4.5 months (range, 1 to 8 months). Transient nephrotoxicity was observed in less than 5% of courses. In all cases, renal function returned to normal within 1 to 2 weeks. Hematologic toxicity was mild and infrequent. Nine patients developed peripheral neuropathy following a median cisplatin dose of 670 mg/m2. Twenty patients experienced mild clinical hearing loss. These data suggest that WR-2721 may potentiate the antitumor activity of cisplatin in metastatic melanoma.

[Catecholamine behavior, adrenoreceptor density of intact cells and sensitivity to catecholamines in a patient with orthostatic hypotension]

We evaluated sympathetic nervous system function in a patient with primary orthostatic hypotension. Plasma catecholamine levels--except for dopamine levels--and urinary catecholamine excretion were decreased, alpha-adrenoreceptor responsiveness to noradrenaline and beta-adrenoreceptor responsiveness to isoproterenol were increased according to increased beta-2-adrenoreceptor density on intact polymorphonuclear leukocytes. Alpha-2-adrenoreceptor density on intact platelets and adrenaline-induced platelet aggregation in vitro, however, were unchanged. We evolved a therapeutic regimen with fludrocortisone, propranolol, and dihydroergotamine that allowed the patient to resume nearly a regular degree of mobility.