2H(e,e(')p)n reaction at high recoil momenta

The 2H(e,e(')p)n cross section was measured in Hall A of the Thomas Jefferson National Accelerator Facility near the top of the quasielastic peak (x(Bj)=0.964) at a four-momentum transfer squared, Q(2)=0.665 (GeV/c) (2) (omega=0.368 GeV, W=2.057 GeV), and for recoil momenta up to 550 MeV/c. The measured cross section deviates by 1-2sigma from a state-of-the-art calculation at low recoil momenta. At high recoil momenta the cross section is well described by the same calculation; however, in this region, final-state interactions and interaction currents are predicted to be large, and alternative choices of nucleon-nucleon potential and nucleon current operator may result in significant spread in the calculations.

Measurement of G(E(p))/G(M(p)) in e(-->)p---> e(-->)p to Q(2) = 5.6 GeV(2)

The ratio of the electric and magnetic form factors of the proton G(E(p))/G(M(p)), which is an image of its charge and magnetization distributions, was measured at the Thomas Jefferson National Accelerator Facility (JLab) using the recoil polarization technique. The ratio of the form factors is directly proportional to the ratio of the transverse to longitudinal components of the polarization of the recoil proton in the elastic e(-->)p---> e(-->)p reaction. The new data presented span the range 3.5< Q(2)< 5.6 GeV(2) and are well described by a linear Q(2) fit. Also, the ratio sqrt[Q(2)] F(2(p))/F(1(p)) reaches a constant value above Q(2) = 2 GeV(2).

Diversity and biogeographical relationships of the Australian cestode fauna

The Australian cestode fauna remains poorly documented with a total of 342 species recorded to date. The best-studied host groups are the elasmobranchs and the marsupials, but even in these groups, only 32 and 25% of known host species, respectively, have been examined for parasites. Overall, cestodes have been reported from only 5% of the known vertebrate species. Representatives of virtually all cestode orders and most of the cyclophyllidean families have been recorded from Australia. In spite of these deficiencies, some biogeographical patterns are discernible. In the elasmobranchs, a significant proportion of the known cestodes is endemic while other associations exist with eastern Pacific and Indo-west Pacific faunas. Also identifiable is a group of cosmopolitan species. The nematotaeniids of amphibians suggest Gondwanan affiliations, while the known proteocephalideans, parasitic in reptiles and amphibians, may represent an Asian invasion. Associations of the avian cestodes represent an unexplored but potentially rewarding avenue of biogeographical study. The cestodes of mammals include families with a Gondwanan distribution (Linstowiidae, Hymenolepididae) as well as those (Anoplocephalidae) with an apparent origin in southeast Asia. In addition, a number of genera of cyclophyllidean cestodes (Anoplotaenia, Dasyurotaenia) occurring in marsupials represent biogeographical challenges, not being accommodated within any of the known cestode families. The Australian cestode fauna therefore provides potentially outstanding opportunities for studies of the biogeographical relationships of a number of cestode groups.

Multifocal fibrosclerosis: a case of thyroiditis and bilateral lacrimal gland involvement

A patient with invasive fibrous thyroiditis (Riedel's thyroiditis), dysphagia, and bilateral lacrimal gland involvement is described. Resolution of the thyroid mass and orbital swellings followed corticosteroid therapy. The unusual ocular features of this case are briefly discussed and the use of corticosteroid and other immunosuppressant therapy in multifocal fibrosclerosis is reviewed.

Despite activation of EGF-receptor-ERK signaling pathway, epithelial proliferation is impaired in portal hypertensive gastric mucosa: relevance of MKP-1, c-fos, c-myc, and cyclin D1 expression

Portal hypertensive (PHT) gastric mucosa has increased susceptibility to injury and impaired mucosal healing. Our previous study demonstrated increased ERK activation and MAP kinase phosphatase-1 (MKP-1) overexpression in PHT gastric mucosa. However, it remains unknown which tyrosine kinase receptors are involved in ERK activation and whether ERK activation results in increased cell proliferation. We examined whether EGF receptor (EGF-R) is involved in ERK activation and whether ERK activation triggers epithelial proliferation in PHT gastric mucosa. In gastric mucosa of PHT and sham-operated (SO) rats we studied: (1) EGF-R mRNA and protein expression as well as phosphorylation and membrane protein tyrosine kinase (PTK) activity; (2) ERK2 phosphorylation and activity; (3) MKP-1 mRNA and protein; (4) c-fos, c-myc and cyclin D1 mRNAs, and gastric epithelial proliferation. In PHT gastric mucosa: (1) EGF-R mRNA, protein and phosphorylation and membrane PTK activity were all significantly increased by 38%, 49%, 43% and 49%, respectively; (2) ERK2 phosphorylation and activity were significantly increased by 40% and 50 %, respectively; (3) MKP-1 mRNA and protein expression were significantly increased by 27% and 34%, respectively. In contrast, (4) c-fos, c-myc, and cyclin D1 mRNAs expression were all significantly decreased in PHT gastric mucosa by 36%, 33%, and 49%, respectively, and cell proliferation was significantly lower that in SO rats (11% in PHT vs. 18% in SO). These results suggest that in PHT gastric mucosa, ERK activation is mediated through EGF-R upregulation, but the gastric epithelial proliferation is impaired, possibly by MKP-1 overexpression, leading to reduction of c-fos, c-myc and cyclin D1.

MAPK (ERK2) kinase--a key target for NSAIDs-induced inhibition of gastric cancer cell proliferation and growth

Limited clinical and experimental studies indicate that nonsteroidal anti-inflammatory drugs (NSAIDs) may inhibit gastric cancer growth. However, the mechanisms involved are not completely understood and cannot be explained by COX-2 inhibition alone. MAPK signaling pathway is essential for cell proliferation, but the effect of NSAIDs on MAPK activity and phosphorylation in gastric cancer has never been studied. Since increased and unregulated cell proliferation and reduced cell apoptosis are important features of cancer growth, we studied whether NS-398, a selective COX-2 inhibitor and/ or indomethacin (IND), a non-selective NSAID: 1) inhibit gastric cancer cell proliferation, 2) whether this inhibition is mediated via MAPK (ERK2), and 3) whether NSAIDs enhance apoptosis in gastric cancer cells. Human gastric epithelial cells (MKN28) derived from gastric tubular adenocarcinoma were cultured and treated with either vehicle, IND (0.25-0.5mM) or NS-398 (50-100 microM) for 6, 16, 24 and 48h.

STUDIES

1) Cellular proliferation was determined by 3H-thymidine uptake. 2) MAPK activity was measured by incorporation of radiolabeled phosphate into myelin basic protein. 3) Apoptosis was evaluated using TUNEL assay. IND and NS-398 significantly inhibited the proliferation of MKN28 cells at 24h by 3.5 - 5 fold (p<0.002) and at 48h by 2.5 - 10 fold (p<0.02). Both NSAIDs also significantly inhibited ERK2 activity: IND >53% inhibition, NS-398, 100 microM >72% inhibition; all p<0.05. Both IND and NS-398 significantly increased apoptotic index. In conclusion, IND and NS-398 significantly inhibit proliferation and growth of human gastric cancer cell line MKN28. This effect is mediated by NSAID-induced inhibition of MAPK (ERK2) kinase signaling pathway, essential for cell proliferation. NSAIDs also increase apoptosis in MKN28 cells. In addition to inhibiting cyclooxygenase, NSAIDs inhibit phosphorylating enzymes--kinases essential for signaling cell proliferation.

Activation of hypoxia inducible factor-1alpha in gastric mucosa in response to ethanol injury: a trigger for angiogenesis?

Gastric mucosal injury triggers angiogenesis and activation of VEGF expression, but the mechanism(s) of VEGF gene activation are not known. In some tissues (e.g. myocardium), hypoxia triggers activation of hypoxia-inducible factor-1alpha (HIF-1alpha), a transcription factor known to activate VEGF gene expression. This study was aimed to determine whether hypoxia and/or alcohol injury may induces HIF-1alpha in gastric mucosa. Normal rat gastric tissue was incubated in organ culture under either hypoxic or normoxic conditions for 6hrs. Rats received, intragastrically, either saline or alcohol and gastric mucosa bordering necrosis was obtained at 1-24hrs. HIF-1alpha mRNA and protein were determined by RT-PCR and Western-blot analysis. HIF-1alpha and VEGF proteins were localized by immunostaining. Incubation of normal gastric mucosa under hypoxia caused a significant elevation of HIF-1alpha mRNA (20+/-2%, p<0.05) and protein (262+/-15%, p<0.005) vs. normoxia. Following alcohol injury, gastric mucosa bordering necrosis demonstrated a significant increase in HIF-1alpha mRNA at 3 and 6hrs (40+/-4%, 19+/-2%; p<0.05), and protein (>300+/-16%; p<0.02 at all time points; highest at 1-3hrs). HIF-1alpha signal was detected in regenerating mucosal microvessels, where it co-localized with VEGF. Since HIF-1alpha initiates transcription of VEGF mRNA, HIF-1alpha activation by ethanol-induced injury is likely responsible for activation of VEGF gene and induction of angiogenesis.

Defective mitogen-activated protein kinase (ERK2) signaling in gastric mucosa of portal hypertensive rats: potential therapeutic implications

Portal hypertensive (PHT) gastropathy is a frequent, serious complication of liver cirrhosis. PHT gastric mucosa has numerous abnormalities such as reduced mucosal potential differences, reduced surface oxygenation, and increased susceptibility to injury caused by alcohol, aspirin, and other noxious factors. Because such mucosal injury is initially mediated by oxygen free radicals, and because mitogen-activated protein (MAP) kinase (ERK2) protects against cellular stress and induces cell proliferation, we postulated that oxidative stress-induced ERK2 activation is defective in PHT gastric mucosa. Here we show that in PHT gastric mucosa, ERK2 activation by oxidative stress is impaired. This impairment is mediated by overexpression of MAP kinase phosphatase-1 (MKP-1), which results from the underlying and continual oxidative state associated with portal hypertension, and is ameliorated by inhibiting MKP-1. Furthermore, we found that supplementing vitamin E, a free radical scavenger, reduces the oxidative state in PHT gastric mucosa, normalizes MKP-1 expression, and thereby reverses impairment of oxidative stress-induced ERK2 activation. Finally, we show that orally administered vitamin E completely reverses the increased susceptibility of PHT gastric mucosa to alcohol injury. Our findings point to a new molecular and mechanistic basis for PHT gastropathy and provide a new therapeutic modality for protection of PHT gastric mucosa.

Gene therapy for gastric ulcers with single local injection of naked DNA encoding VEGF and angiopoietin-1

BACKGROUND & AIMS

Angiogenesis, formation of new capillary blood vessels, is crucial for gastroduodenal ulcer healing because it enables delivery of oxygen and nutrients to the healing site. Because angiogenesis is stimulated by vascular endothelial growth factor (VEGF) and angiopoietin-1 (Ang1), we studied whether local gene therapy with nonviral DNA encoding VEGF and/or Ang1 into the ulcer base could accelerate ulcer healing through enhanced angiogenesis.

METHODS

Gastric ulcers were induced in rats by acetic acid applied to the serosal surface of the stomach, and the site around the ulcer was injected with nonviral plasmid-encoding full-length complementary DNA (cDNA) of human recombinant (rh) VEGF165, rhAng1, or their combination. For some studies, neutralizing anti-VEGF antibody was administered.

RESULTS

Single local injection of plasmids encoding VEGF165 and Ang1 significantly increased neovascularization and accelerated ulcer healing. A neutralizing anti-VEGF antibody significantly reduced the acceleration of ulcer healing resulting from the treatment. Coinjection of both plasmids encoding rhVEGF165 and rhAng1 resulted in formation of more mature vessels and to more complete restoration of gastric glandular structures within the ulcer scar. However, this did not result in further reduction of ulcer size.

CONCLUSIONS

VEGF and Ang1 gene therapy, with limited duration of target gene expression, significantly accelerates gastric ulcer healing. Coinjection of both plasmids leads to more complete structural restoration. Inhibition of accelerated healing by a neutralizing anti-VEGF antibody indicates an essential role for VEGF and enhanced angiogenesis in ulcer healing.

Echinobothrium chisholmae n. sp. (Cestoda, Diphyllidea) from the giant shovel-nose ray Rhinobatos typus from Australia, with observations on the ultrastructure of its scolex musculature and peduncular spines

Echinobothrium chisholmae n. sp. is described from Rhinobatos typus Bennett (Rhinobatidae), collected from Heron Island, Great Barrier Reef, Australia. E. chisholmae differs from all congeners in possessing 11 hooks in each dorsal and ventral group on the rostellum and groups of 3-6 hooklets on either side of the hooks. A single metacestode of E. chisholmae was collected from the decapod crustacean Penaeus longistylus Kubo. Yellow pigmentation of the cephalic peduncle in immature adults is caused by the accumulation of large vesicles in the distal cytoplasm of the tegument. The vesicles probably provide materials for spine formation. Ultrastructural examination of the rostellar musculature revealed that the muscles are stratified (striated-like), consisting of a periodic repetition of sarcomeres separated by perforated Z-like lines that are oblique to the long axes of the myofilaments.

Giardia trophozoites in dog hookworm, Ancylostoma caninum: accident or hyperparasitism?

During the course of transmission electron microscopic studies of adult Ancylostoma caninum removed from a dog, several Giardia trophozoites were found in sections of the buccal cavity, oesophagus and intestine of several hookworms. Although the protozoa appeared viable, this unusual finding probably represents accidental uptake by, rather than an established infection of, the hookworm. It is feasible, however, that the trophozoites might have survived and even multiplied in this aberrant site.

Structure of apolipoprotein B-100 in low density lipoproteins

There is general consensus that amphipathic alpha-helices and beta sheets represent the major lipid-associating motifs of apolipoprotein (apo)B-100. In this review, we examine the existing experimental and computational evidence for the pentapartite domain structure of apoB. In the pentapartite nomenclature presented in this review (NH(2)-betaalpha(1)-beta(1)-alpha(2)-beta(2)-alpha(3)-COOH), the original alpha(1) globular domain (Segrest, J. P. et al. 1994. Arterioscler. Thromb. 14: 1674;-1685) is expanded to include residues 1;-1,000 and renamed the betaalpha(1) domain. This change reflects the likelihood that the betaalpha(1) domain, like lamprey lipovitellin, is a globular composite of alpha-helical and beta-sheet secondary structures that participates in lipid accumulation in the co-translationally assembled prenascent triglyceride-rich lipoprotein particles. Evidence is presented that the hydrophobic faces of the amphipathic beta sheets of the beta(1) and beta(2) domains of apoB-100 are in direct contact with the neutral lipid core of apoB-containing lipoproteins and play a role in core lipid organization. Evidence is also presented that these beta sheets largely determine LDL particle diameter. Analysis of published data shows that with a reduction in particle size, there is an increase in the number of amphipathic helices of the alpha(2) and alpha(3) domains associated with the surface lipids of the LDL particle; these increases modulate the surface pressure decreases caused by a reduction in radius of curvature. The properties of the LDL receptor-binding region within the overall domain structure of apoB-100 are also discussed. Finally, recent three-dimensional models of LDL obtained by cryoelectron microscopy and X-ray crystallography are discussed. These models show three common features: a semidiscoidal shape, a surface knob with the dimensions of the betaC globular domain of lipovitellin, and planar multilayers in the lipid core that are approximately 35 A apart; the multilayers are thought to represent cholesteryl ester in the smectic phase. These models present a conundrum: are LDL particles circulating at 37 degrees C spheroidal in shape, as generally assumed, or are they semidiscoidal in shape, as suggested by the models? The limited evidence available supports a spheroidal shape.

Danger Ideation Reduction Therapy (DIRT) for treatment-resistant compulsive washing

Five intractable cases of obsessive-compulsive disorder were treated with the Danger Ideation Reduction Therapy (DIRT) program. All five cases: (1) had displayed excessive washing/cleaning behaviour for at least 10 years; (2) had failed to respond to a minimum of two separate, 12-week drug trials with serotonergic agents; (3) failed to respond to at least 15 sessions of exposure and response prevention at the beginning of the present trial, and; (4) satisfied the DSM-IV criteria for OCD with Poor Insight. DIRT was conducted in 14, weekly, individual sessions or until, in the judgement of the treating clinician: (1) clinically significant gains were apparent with minimal symptomatology remaining, and (2) clients displayed a sound grasp of the cognitive model underpinning DIRT procedures. At post-treatment, substantial reductions in scores on the Padua Inventory (PI), Maudsley Obsessional-Compulsive Inventory (MOCI), Beck Depression Inventory-II (BDI-II) and two global rating scales were apparent for four of the five subjects. These improvements were maintained at 4-to-6 month follow-up, with four of the five cases meeting Jacobson and Truax's (1991) criteria for 'recovery' on the MOCI and the PI by this assessment stage. While one subject remained non-responsive, the present findings suggest that DIRT may be a viable option for treatment-resistant cases of compulsive washing. The theoretical implications of the findings are discussed.

Immunolocalization of the 38.3 kDa calponin-like protein in stratified muscles of the tail of Schistosoma japonicum cercariae

Calponins are proteins present in vertebrate smooth musculature where they occur in association with thin myofilaments. Calponins are not present in vertebrate or invertebrate striated muscles. The blood fluke Schistosoma japonicum expresses a 38.3-kDa protein that bears substantial homology with vertebrate calponin and occurs entirely within smooth musculature of adults. Calponin-like immunoreactivity has been demonstrated in smooth muscles of many invertebrate phyla. The Schistosoma japonicum calponin has been localised in smooth myofibrils of adults where it is associated with myofilaments and sarcoplasmic reticulum. In this study, the ultrastructural localisation of the protein in muscles of S. japonicum cercariae is described. The protein is present in smooth muscles of the forebody and the stratified muscle of the tail. Within the stratified layer, the protein occurs predominantly in transverse arrays of sarcoplasmic reticulum. The localisation data suggest that the calponin-like protein of S. japonicum is involved in contraction of the stratified tail muscle. Furthermore, the presence of a calponin system in the stratified muscle suggests that this muscle is simply a superior form of muscle, closely related to smooth muscles that use a caldesmin-calponin system in contraction.

Receptor for Fc on the surfaces of schistosomes

Schistosoma mansoni masks its surface with adsorbed host proteins including erythrocyte antigens, immunoglobulins, major histocompatibility complex class I, and beta(2)-microglobulin (beta(2)m), presumably as a means of avoiding host immune responses. How this is accomplished has not been explained. To identify surface receptors for host proteins, we biotinylated the tegument of live S. mansoni adults and mechanically transformed schistosomula and then removed the parasite surface with detergent. Incubation of biotinylated schistosome surface extracts with human immunoglobulin G (IgG) Fc-Sepharose resulted in purification of a 97-kDa protein that was subsequently identified as paramyosin (Pmy), using antiserum specific for recombinant Pmy. Fc also bound recombinant S. mansoni Pmy and native S. japonicum Pmy. Antiserum to Pmy decreased the binding of Pmy to Fc-Sepharose, and no proteins bound after removal of Pmy from extracts. Fluoresceinated human Fc bound to the surface, vestigial penetration glands, and nascent oral cavity of mechanically transformed schistosomula, and rabbit anti-Pmy Fab fragments ablated the binding of Fc to the schistosome surface. Pmy coprecipitated with host IgG from parasite surface extracts, indicating that complexes formed on the parasite surface as well as in vitro. Binding of Pmy to Fc was not inhibited by soluble protein A, suggesting that Pmy does not bind to the region between the CH2 and CH3 domains used by many other Fc-binding proteins. beta(2)m did not bind to the schistosome Fc receptor (Pmy), a finding that contradicts reports from earlier workers but did bind to a heteromultimer of labeled schistosomula surface proteins. This is the first report of the molecular identity of a schistosome Fc receptor; moreover it demonstrates an additional aspect of the unusual and multifunctional properties of Pmy from schistosomes and other parasitic flatworms.

Dynamics of the 16O(e, e'p) reaction at high missing energies

We measured the cross section and response functions for the quasielastic 16O(e,e'p) reaction for missing energies 25< or =E(m)< or =120 MeV at missing momenta P(m)< or =340 MeV/c. For 25<E(m)<50 MeV and P(m) approximately 60 MeV/c, the reaction is dominated by a single 1s(1/2) proton knockout. At larger P(m), the single-particle aspects are increasingly masked by more complicated processes. Calculations which include pion exchange currents, isobar currents, and short-range correlations account for the shape and the transversity, but for only half of the magnitude of the measured cross section.

Tetraphyllidean metacestodes of teleosts of the Great Barrier Reef, and the use of in vitro cultivation to identify them

The tetraphyllidean metacestode diversity of 310 teleost fishes, including 87 species from 31 families, was examined from Heron Island, The Great Barrier Reef, Australia. Eleven metacestode 'types' were identified with the use of light microscopy. Host-specificity varied greatly among metacestode types. Incorporation of in vitro cultivation allowed generic identification for some types. Types 1 and 2 belong to Uncibilocularis Southwell, 1925, and have triloculate bothridia and one pair of forked hooks with unequal prongs; Type 3 has quadriloculate bothridia. Hook development was insufficient to determine in which genus, Acanthobothrium van Beneden, 1849 or Calliobothrium van Beneden, 1850, this type may belong. Type 4 has unilocular bothridia with simple edges and belongs to Anthobothrium van Beneden, 1850. Type 5 has multiloculated bothridia which are invaginated within pouches. This type belongs to the Rhinebothriinae although its generic identity cannot be determined. The bothridia of Type 5 everted within 24 hours of in vitro cultivation and revealed the presence of two forms, one having 48 loculi per bothridium, the other 72 per bothridium. In vitro studies provide additional support for existing theories of onchobothriid scolex development.

Polarization measurements in high-energy deuteron photodisintegration

We present measurements of the recoil proton polarization for the d(gamma-->,p-->)n reaction at straight theta(c.m.) = 90 degrees for photon energies up to 2.4 GeV. These are the first data in this reaction for polarization transfer with circularly polarized photons. The induced polarization p(y) vanishes above 1 GeV, contrary to meson-baryon model expectations, in which resonances lead to large polarizations. However, the polarization transfer Cx does not vanish above 1 GeV, inconsistent with hadron helicity conservation. Thus, we show that the scaling behavior observed in the d(gamma,p)n cross sections is not a result of perturbative QCD. These data should provide important tests of new nonperturbative calculations in the intermediate energy regime.