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At least 649 records · Page 36Linked to original sources
PubMed1998

Antiangiogenic properties of a novel shark cartilage extract: potential role in the treatment of psoriasis.

BACKGROUND: A number of inflammatory and immune diseases are associated with vascular changes. Psoriasis, as an example, is a common inflammatory skin disease with dilation of capillaries as an early histological change. In more developed psoriatic lesions there is proliferation of blood vessels and neovascularization. The use of agents that target these vascular changes represents a novel therapeutic strategy in the treatment of inflammatory diseases. Since cartilage is an avascular tissue, it has been hypothesized that there may be factors found in cartilage that inhibit blood vessel formation. OBJECTIVE: The objectives of this study were 1) to determine whether extracts of cartilage could inhibit angiogenesis, and 2) since altered angiogenesis is associated with certain diseases, including psoriasis, to examine whether inhibition of angiogenesis could potentially contribute to the treatment of psoriasis. METHODS: Extracts of shark cartilage were prepared by homogenization and ultrafiltration to derive the active agent termed AE -941. This agent was tested for antiangiogenesis activity using the embryonic vascularization test, which is a modification of the ex vivo chick embryo culture (CAM). Since one of the first steps in angiogenesis is degradation by metalloproteinases of the basement membrane of capillaries, AE -941 was tested for collagenase activity using a fluorogenic peptide substrate. Anti-inflammatory properties were tested using a cutaneous irritation model in humans. RESULTS: A dose dependent inhibition in embryonic neovascularization as well as in collagenase activity by AE -941 was demonstrated. When test compounds were applied on the forearms of test subjects, AE -941 was shown to have anti-inflammatory properties. Anecdotal data suggested that topical AE -941 had a beneficial effect in psoriasis. CONCLUSION: Our results show that AE -941 has anti-angiogenic and anti-inflammatory properties. Antiangiogenesis agents such as AE -941 provide an entirely new class of agents to treat cutaneous and systemic diseases associated with altered vascularity.

Animals↗
PubMed2003

The interleukin 1 (IL-1) system in the uteroplacental complex of a cartilaginous fish, the smoothhound shark, Mustelus canis.

Cartilaginous fish are the oldest extant jawed vertebrates and the oldest line to have placentae. Their pivotal evolutionary position makes them attractive models to investigate the mechanisms involved in the maternal-fetal interaction. This study describes the tissue expression of the cytokine interleukin-1 (IL-1) alpha, IL-1 beta and its specific membrane receptor, IL-1 receptor type I (IL-1R tI) in a placental cartilaginous fish, the smoothhound shark, Mustelus canis. The presence of this cytokine has been reported in many mammalian placentae, as well as in the placenta of a squamate reptile and this study extends these observations to the cartilaginous fishes. The uteroplacental complex in M. canis consists of a yolk sac modified into a functional yolk sac placenta and complimentary uterine attachment sites. Immunohistochemistry for IL-1 alpha, IL-1 beta and the receptor reveals leucocytes of both the mother and fetus to be positive, as well as the apical aspect of paraplacental cells and the apical vesicles in the umbilical cord epithelium. Yolk sac endoderm is also positive with all the stains while the ectoderm is positive only for IL-1 alpha. Immunoreactivity in the uterine epithelium was obtained for IL-1 alpha and the receptor. The egg envelope is always negative. In light of the recent finding of IL-1 beta gene in a cartilaginous fish and of the high level of conservation of proteins implicated in IL-1 action, our data suggest that IL-1 system is a key mediator of the materno-fetal interaction since the oldest extant placental vertebrates.

Animals↗
PubMed1998

Phase I/II trial of the safety and efficacy of shark cartilage in the treatment of advanced cancer.

PURPOSE: Patients with cancer and chronic inflammatory disorders have used shark cartilage (SC) preparations for many years. Preclinical studies that support their beneficial effects are scanty, and reports of clinical trials have been anecdotal. The proposed mechanisms of antitumor action include direct or indirect inhibition of angiogenesis. Because of the emerging use of SC as an alternative to conventional cancer therapy, this trial was launched to evaluate the safety and efficacy of SC. PATIENTS AND METHODS: Sixty adult patients with advanced previously treated cancer (breast, 16 patients; colorectal, 16 patients; lung, 14 patients; prostate, eight patients; non-Hodgkin lymphoma, three patients; brain, one patient; and unknown primary tumor, two patients) were enrolled. Eligibility criteria included confirmation of diagnosis, resistance to conventional therapy, objective measurable disease, life expectancy of 12 weeks or greater, Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2, no recent or concomitant anticancer therapy, no prior SC, and informed consent. Patients underwent evaluation of the extent of disease, quality-of-life score (Functional Assessment of Cancer Therapy-General [FACT-G] scale), and hematologic, biochemical, and selected immune function studies at baseline and after 6 and 12 weeks of SC therapy. The dose of SC was 1 g/kg daily orally in three divided doses. Standard criteria were used to evaluate adverse events and response. RESULTS: Ten of 60 patients were lost to follow-up(LTFU) or refused further treatment (RFT) before the 6-week evaluation and were not assessable for toxicity and response. Three patients with stable disease at 6 weeks were LTFU or RFT thereafter. Of the 47 fully assessable patients, five were taken off study because of gastrointestinal toxicity or intolerance to SC. Progressive disease (PD) at 6 or 12 weeks occurred in 22 and five patients, respectively. Five patients died of PD while undergoing SC therapy. No complete (CRs) or partial responses (PRs) were noted. Median time to tumor progression in the entire study population was 7+/-9.7 weeks (mean, 11.4 weeks; range, 3.7 to 45.7 weeks). Ten (20%) of 50 assessable patients, or 16.7% of the 60 intent-to-treat patients, had stable disease (SD) for 12 weeks or more. The median time to tumor progression was 27 weeks, the mean was 28.8+/-9.9 weeks, and the range was 18.6 to 45.7 weeks. In this subset, FACT-G scores improved in four patients, were unchanged in four patients, and declined in two patients. Twenty-one adverse events (grade 1, eight events; grade 2, seven events; and grade 3, six events) were recorded, 14 of which were gastroenterologic (nausea, vomiting, constipation). CONCLUSION: Under the specific conditions of this study, SC as a single agent was inactive in patients with advanced-stage cancer and had no salutary effect on quality of life. The 16.7% rate of SD was similar to results in patients with advanced cancer treated with supportive care alone.

Adolescent↗
PubMed2006

Metabolic organization of freshwater, euryhaline, and marine elasmobranchs: implications for the evolution of energy metabolism in sharks and rays.

To test the hypothesis that the preference for ketone bodies rather than lipids as oxidative fuel in elasmobranchs evolved in response to the appearance of urea-based osmoregulation, we measured total non-esterified fatty acids (NEFA) in plasma as well as maximal activities of enzymes of intermediary metabolism in tissues from marine and freshwater elasmobranchs, including: the river stingray Potamotrygon motoro (<1 mmol l(-1) plasma urea); the marine stingray Taeniura lymma, and the marine shark Chiloscyllium punctatum (>300 mmol l(-1) plasma urea); and the euryhaline freshwater stingray Himantura signifer, which possesses intermediate levels of urea. H. signifer also were acclimated to half-strength seawater (15 per thousand) for 2 weeks to ascertain the metabolic effects of the higher urea level that results from salinity acclimation. Our results do not support the urea hypothesis. Enzyme activities and plasma NEFA in salinity-challenged H. signifer were largely unchanged from the freshwater controls, and the freshwater elasmobranchs did not show an enhanced capacity for extrahepatic lipid oxidation relative to the marine species. Importantly, and contrary to previous studies, extrahepatic lipid oxidation does occur in elasmobranchs, based on high carnitine palmitoyl transferase (CPT) activities in kidney and rectal gland. Heart CPT in the stingrays was detectable but low, indicating some capacity for lipid oxidation. CPT was undetectable in red muscle, and almost undetectable in heart, from C. punctatum as well as in white muscle from T. lymma. We propose a revised model of tissue-specific lipid oxidation in elasmobranchs, with high levels in liver, kidney and rectal gland, low or undetectable levels in heart, and none in red or white muscle. Plasma NEFA levels were low in all species, as previously noted in elasmobranchs. D-beta-hydroxybutyrate dehydrogenase (d-beta-HBDH) was high in most tissues confirming the importance of ketone bodies in elasmobranchs. However, very low d-beta-HBDH in kidney from T. lymma indicates that interspecific variability in ketone body utilization occurs. A negative relationship was observed across species between liver glutamate dehydrogenase activity and tissue or plasma urea levels, suggesting that glutamate is preferentially deaminated in freshwater elasmobranchs because it does not need to be shunted to urea production as in marine elasmobranchs.

Acclimatization↗
PubMed1994

The molecular basis of chloride transport in shark rectal gland.

Transepithelial Cl- secretion in vertebrates is accomplished by a secondary active transport process brought about by the coordinated activity of apical and basolateral transport proteins. The principal basolateral components are the Na+/K(+)-ATPase pump, the Na+/K+/2Cl- cotransporter (symporter) and a K+ channel. The rate-limiting apical component is a cyclic-AMP-stimulated Cl- channel. As postulated nearly two decades ago, the net Cl- movement from the blood to the lumen involves entry into the epithelial cells with Na+ and K+, followed by active Na+ extrusion via the pump and passive K+ exit via a channel. Intracellular [Cl-] is raised above electrochemical equilibrium and exits into the lumen when the apical Cl- channel opens. Cl- secretion is accompanied by a passive paracellular flow of Na+. The tubules of the rectal glands of elasmobranchs are highly specialized for secreting concentrated NaCl by this mechanism and hence have served as an excellent experimental model in which to characterize the individual steps by electrophysiological and ion flux measurements. The recent molecular cloning and heterologous expression of the apical Cl- channel and basolateral cotransporter have enabled more detailed analyses of the mechanisms and their regulation. Not surprisingly, since hormones acting through kinases control secretion, both the Cl- channel, which is the shark counterpart of the CFTR (Cystic Fibrosis Transmembrane Conductance Regulator), and the cotransporter are regulated by phosphorylation and dephosphorylation. The primary stimulation of secretion by hormones employing cyclic AMP as second messenger activates CFTR via the direct action of protein kinase A (PKA), which phosphorylates multiple sites on the R domain. In contrast, phosphorylation of the cotransporter by as yet unidentified kinases is apparently secondary to the decrease in intracellular chloride concentration caused by anion exit through CFTR.

Animals↗
PubMed1976

An experimental model for the study of endolymphatic hydrops in sharks: implications for the clinician.

In recent years, attention has focused on the role of the endolymphatic sac (ELS) and the endolymphatic duct (ELD) in the pathogenesis of endolymphatic hydrops (ELH). Changes have been noted surgically and radiographically by others in the ELS and ELD in patients with ELH. This report summarizes the development of a shark model with which to study the pathophysiology of ELH. The background material and overall results of anatomic, histopathologic, and ultrastructural studies using the model are presented. Possible implications for the clinical handling of ELH as a result of this work is emphasized.

Animals↗
PubMed1993

Shark oil pneumonia. An overlooked entity.

Nonprescription drugs are often believed to be innocuous. We present a case of lipoid pneumonia from ingestion of squalene, a derivative of shark liver oil, a popular over-the-counter Asian folk remedy.

Animals↗
PubMed1985

The primary structure of the hemoglobin of the dogfish shark (Squalus acanthias). Antagonistic effects of ATP and urea on oxygen affinity of an elasmobranch hemoglobin.

The amino-acid sequence of the hemoglobin of the Dogfish Shark (Squalus acanthias) is presented. The alpha-chains consist of 141 residues and show a Thr/Ser ambiguity at position 3. The beta-chains consist of 142 residues and evidently have no D-helix; they show an Asn/Tyr ambiguity at position 104. Both chains have free N-terminal amino acids. The phylogenetic distance from the human alpha- and beta-chains is indicated by 49.3% and 56.2% amino-acid exchanges. The primary structure is discussed in relation to the oxygen-binding properties of elasmobranch hemoglobin, particularly as regards the antagonistic effects of urea and ATP, and the effects of proton concentration (the alkaline and acid Bohr effects, and the Root effect).

Adenosine Triphosphate↗
PubMed2004

The Dlx gene complement of the leopard shark, Triakis semifasciata, resembles that of mammals: implications for genomic and morphological evolution of jawed vertebrates.

Extensive gene duplication is thought to have occurred in the vertebrate lineage after it diverged from cephalochordates and before the divergence of lobe- and ray-finned fishes, but the exact timing remains obscure. This timing was investigated by analysis of the Dlx gene family of a representative cartilaginous fish, the leopard shark, Triakis semifasciata. Dlx genes encode homeodomain transcription factors and are arranged in mammals as three convergently transcribed bigene clusters. Six Dlx genes were cloned from Triakis and shown to be orthologous to single mammalian Dlx genes. At least four of these are arranged in bigene clusters. Phylogenetic analyses of Dlx genes were used to propose an evolutionary scenario in which two genome duplications led to four Dlx bigene clusters in a common ancestor of jawed vertebrates, one of which was lost prior to the diversification of the group. Dlx genes are known to be involved in jaw development, and changes in Dlx gene number are mapped to the same branch of the vertebrate tree as the origin of jaws.

Amino Acid Sequence↗
PubMed2000

Marine leech, Stibarobdella macrothela (Schmarda, 1861) (Hirudinea, piscicolidae), parasitic on the whaler shark, Carcharhinus Brachyurus (Günther, 1870) (Chondrichthyes, Carcharhinidae), in Southern Brazilian waters.

The presence of the sea leech, Stibarobdella macrothela (Schmarda, 1861) (Hirudinea, Piscicolidae), is marked in the south coast of Brazil, based on the single specimen with 67 mm (CT), collected in the intergill ventral region of a whaler shark, Carcharhinus brachyurus (Günther, 1870) (Chondrichtyes, Carcharhinidae), adult male with about 2 m (CT), being treated of the first registrations of S. macrothela in the Southwest Atlantic and the parasitic association with C. brachyurus.

Animals↗
PubMed2006

Description of a new diphyllidean parasite of triakid sharks from the deep Red Sea.

Specimens of Echinobothrium diamanti n. sp. (Cestoda: Diphyllidea) were recovered from the spiral intestine of Iago omanensis and Mustelus mosis (Carcharhiniformes: Triakidae), in the Gulf of Aqaba, Red Sea. The new species can be distinguished from all other species in Echinobothrium by the presence of a conspicuous vaginal sphincter. Echinobothrium diamanti possesses a corona of spines between the apical armature and the bothria, as in Echinobothrium notoguidoi, Echinobothrium musteli, and Echinobothrium scoliodoni, also parasites of sharks. However, E. diamanti possesses more testes per proglottid than E. notoguidoi and E. scoliodoni, and it is larger and has more spines per column on the cephalic peduncle than E. musteli and E. notoguidoi, and it also has circum-medullary vitelline follicles rather than distributed in lateral columns. Echinobothrium diamanti is the first species of diphyllidean reported from the triakid genus Iago.

Animals↗
PubMed2005

The sexually dimorphic cephalofoil of bonnethead sharks, Sphyrna tiburo.

Sexually dimorphic head shape is common in vertebrates from teleosts to mammals. Herein we document that cephalic sexual dimorphism is also found in the cartilaginous fishes (Chondrichthyes). Male bonnethead sharks develop a prominent bulge along the anterior margin of the cephalofoil at the onset of sexual maturity. This contrasts with the uniformly rounded anterior margin of adult females and juveniles and embryos of both sexes. The anterior cephalic bulge is produced by elongation of the rod-like rostral cartilages, and its appearance corresponds temporally with the elongation of the rod-like cartilages of the male intromittent organs (claspers). We propose that the rostral cartilage elongation is a byproduct of endocrinological changes at the onset of sexual maturity that stimulate growth of the clasper cartilages. The basal location of the chondrichthyan fishes within the vertebrate clade extends the earliest appearance of cephalic sexual dimorphism among the vertebrates.

Animals↗
PubMed2005

Study on hepatoprotective effect of peptide S-8300 from shark liver.

AIM: To explore the effects of peptide S-8300 from shark liver (S-8300) on liver function as well as in regulating immune functions in experimental injury models. METHODS: Mice were administered with different doses of S-8300 for four consecutive days, followed by mice injected with tetrachloromethane (CCl(4)) on d 3. The activity of ALT, AST, LDH, SOD and contents of MDA and GSH in the mice liver were tested. And mice were treated with Cy (100 mg/kg) at the beginning of the experiment to induce immunosuppression model. The S-8300 groups were treated with S-8300 seven days after the beginning of Cy administration. The effects of S-8300 on the formulation of serum hemolysin and the content of IL-2 in serum in the immunosuppression mice were observed. RESULTS: S-8300 obviously decreased the level of ALT (52.2+/-11.0 U/dL vs 135.9+/-6.5 U/dL, P<0.01), AST (67.5+/-6.9 U/dL vs 238.8+/-8.7 U/dL, P<0.01), LDH (155.1+/-46.8 U/dL vs 240.4+/-6.0 U/dL, P<0.01) and MDA (0.64+/-0.027 nmol/mg vs 1.06+/-0.040 nmol/mg, P<0.01) and increased SOD (24.51+/-1.01 U/mg vs 19.05+/-0.73 U/mg, P<0.01) and GSH (24.17+/-0.91 microg/mg vs 14.93+/-0.45 microg/mg, P<0.01) in mice liver damaged by CCl(4). S-8300 also markedly improved the formulation of serum hemolysin (0.094+/-0.005 A(540) vs 0.063+/-0.006 A(540), P<0.01) and increased the level of IL-2 (9.74+/-1.16 pg/mL vs 5.81+/-0.87 pg/mL, P<0.01) in serum of the immunosuppression mice. CONCLUSION: The results suggested S-8300 has significant hepatoprotective, immunomodulatory and inhibiting of lipid peroxidation activity.

Animals↗
PubMedDate not supplied

Inhibitory effect of shark liver oil on cutaneous angiogenesis induced in Balb/c mice by syngeneic sarcoma L-1, human urinary bladder and human kidney tumour cells.

The effect of shark liver oil on cutaneous angiogenesis induced in mice by intradermal grafting of tumour cells was evaluated. It was shown that this substance (Ecomer) suppressed neovascular response in mice grafted with sarcoma L-1 syngeneic cells, human kidney cancer and human urinary bladder cancer cells. In addition, strong stimulatory effect of this drug on mice blood granulocyte number and their metabolic activity was observed.

Animals↗
PubMed1987

Urogenital sinus calculi in a sand tiger shark (Odontaspis taurus).

Two calculi were found in the urogenital sinus of a 70 kg female sand tiger shark (Odontaspis taurus). The calculi were white in color, rough surfaced, and spherical in shape. Crystallographic examination revealed that they were composed of magnesium ammonium phosphate hexahydrate (80% struvite) and calcium phosphate (15% carbonate apatite). Approximately 5% of the stone matrix consisted of blood and protein and a distinct bacterial nidus was not present microscopically.

Animals↗
PubMed1993

Parasitic meningoencephalitis in nurse sharks (Ginglymostoma cirratum).

Based on microscopic examination of the brains of seven wild-caught nurse sharks (Ginglymostoma cirratum), we observed a severe meningoencephalitis associated with numerous parasitic granulomas. The parasites were larval nematodes with morphological characteristics of the Superfamily Dracunculoidea. Although meningeal larval aggregates were associated with chronic inflammation, additional parasitic nodules found on the endocardial surface and perimandibular region did not provoke an inflammatory response. Neither the route of infection nor life cycle were determined.

Animals↗
PubMed2000

Observations on a lesser-known monogenean, Udonella myliobati, from a copepod parasite, Lepeophtheirus natalensis, parasitizing the spotted ragged-tooth shark, Carcharias taurus, from South African waters.

The phylogeny of the genus Udonella has been disputed for quite some time, but recent phylogenetic analysis of molecular data confirms that the genus is a monopisthocotylean monogenean. Specimens of Udonella myliobati parasitizing the copepod Lepeophtheirus natalensis, an ectoparasite of the spotted ragged-tooth shark, (Carcharias taurus), were collected and studied. A total of 771 monogenean specimens were recovered from 54 infected copepods examined, with a mean intensity of 14,3 worms per copepod. Most of the monogeneans were found attached to the dorsal surface of the lateral and frontal marginal membranes of the copepod carapace. Eggs, with filaments and adhesive discs, were found ventrally on the host, mainly attached to the maxillae and maxillipeds, in clusters of 12-14. Observations on the morphology, distribution and behaviour of this monogenean are presented with the aid of light and scanning electron microscopy.

Animals↗
PubMed1975

Isolation and identification of prostaglandin E2 from gastrointestinal tract of shark Triakis scyllia.

A prostaglandin was isolated from the gastrointestinal tract of the shark Triakis scyllia and identified as prostaglandin E2 by bioassay, thin-layer chromatography, gas-liquid chromatography, ultraviolet absorption spectrometry and mass spectrometry. The fatty acid composition of the tissue was also determined. The amount of eicosatetraenoic acid in this tissue was 17.2% of the total fatty acids, but the percentages of eicosatrienoic acid and eicospentaenoid acid were low.

Animals↗