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At least 145 records · Page 8Linked to original sources
PubMed2005

Maxilla sinus grafting with marine algae derived bone forming material: a clinical report of long-term results.

PURPOSE: Autogenous bone grafting continues to be considered the gold standard for sinus grafting. For the past 15 years the author has used an alternative graft material and followed-up the input/output statistic of implants to evaluate if this material results similar to the autogenous bone graft. Histomorphometric evaluations of graft materials show how much new bone is formed and if the graft material is resorbed. MATERIALS AND METHODS: In our study we used a marine derived carbonated red algae that is chemically converted into hydroxyapatite (HA). This material is distributed worldwide as the Communauté Européenne approved material AlgiPore (Dentsply Friadent, Mannheim, Germany), as the US Food and Drug Administration approved material C GRAFT (The Clinician Preference LLC, Golden, CO), and the Russian approved material AlgOss (Unexim Co, Moscow, Russia). A total of 209 sinus grafts were performed on 118 patients who presented with a severely resorbed maxillary alveolar process with 1 to 5 mm (mean, 3.6 mm) of remaining bone. The available bone was comparable to Class D bone as described by Simion et al. After 6 months implants were placed and 6 months later the implants were loaded. RESULTS: From September 5, 1990, to September 1, 2004, the author performed 209 sinus grafts on 118 patients. The longest observation period of loaded implants in this study is 156 months (13 years). Implant loss was 27 out of 614 loaded implants (4.4%), showing a survival rate of 95.6%. Smokers and women over 50 are included. Although AlgiPore/C GRAFT/AlgOss (ACA) undergoes a resorption process, we found only 14% volume loss after 6.4 months compared with 49.5% after 6 months when autogenous bone was used. CONCLUSION: This retrospective study of over 14 years shows once again that the sinus lift procedure with grafting of the sinus floor and subsequent implant placement is a proven method. This 14-year longitudinal study shows that the marine derived HA material ACA in a mixture with approximately 10% autogenous collector bone and blood or platelet rich plasma is able to enhance enough new bone in 6 months to allow implant osseointegration after 6 more months with a high implant survival rate.

Absorbable Implants↗
PubMed1992

Iron-induced changes in light harvesting and photochemical energy conversion processes in eukaryotic marine algae.

The role of iron in regulating light harvesting and photochemical energy conversion processes was examined in the marine unicellular chlorophyte Dunaliella tertiolecta and the marine diatom Phaeodactylum tricornutum. In both species, iron limitation led to a reduction in cellular chlorophyll concentrations, but an increase in the in vivo, chlorophyll-specific, optical absorption cross-sections. Moreover, the absorption cross-section of photosystem II, a measure of the photon target area of the traps, was higher in iron-limited cells and decreased rapidly following iron addition. Iron-limited cells exhibited reduced variable/maximum fluorescence ratios and a reduced fluorescence per unit absorption at all wave-lengths between 400 and 575 nm. Following iron addition, variable/maximum fluorescence ratios increased rapidly, reaching 90% of the maximum within 18 to 25 h. Thus, although more light was absorbed per unit of chlorophyll, iron limitation reduced the transfer efficiency of excitation energy in photosystem II. The half-time for the oxidation of primary electron acceptor of photosystem II, calculated from the kinetics of decay of variable maximum fluorescence, increased 2-fold under iron limitation. Quantitative analysis of western blots revealed that cytochrome f and subunit IV (the plastoquinone-docking protein) of the cytochrome b(6)/f complex were also significantly reduced by lack of iron; recovery from iron limitation was completely inhibited by either cycloheximide or chloramphenicol. The recovery of maximum photosynthetic energy conversion efficiency occurs in three stages: (a) a rapid (3-5 h) increase in electron transfer rates on the acceptor side of photosystem II correlated with de novo synthesis of the cytochrome b(6)/f complex; (b) an increase (10-15 h) in the quantum efficiency correlated with an increase in D1 accumulation; and (c) a slow (>18 h) increase in chlorophyll levels accompanied by an increase in the efficiency of energy transfer from the light-harvesting chlorophyll proteins to the reaction centers.

Journal Article↗
PubMed1995

Toxin of the marine alga Prymnesium patelliferum enhances voltage dependent Ca(2+)-currents, elevates the cytosolic Ca(2+)-concentration and facilitates hormone release in clonal rat pituitary cells.

The marine flagellate Prymnesium patelliferum produces toxins lethal to fish. The toxin extracted from the alga has haemolytic, cytotoxic and neurotoxic effects, but the action mechanisms of the toxin are not known in detail. We have examined the toxin effects on the voltage sensitive Ca(2+)-currents, the cytosolic Ca(2+)-level ([Ca2+]i) and the prolactin release in clonal rat anterior pituitary GH4C1 cells, which possess T- and L-type Ca(2+)-channels. The trans-membrane Ca(2+)-current was recorded using whole-cell voltage clamp. After 5-15 min exposure to the algal toxin at a final concentration of 50,000-100,000 cells mL-1, the Ca(2+)-currents through both the T- and L-channels showed a 2-3-fold enhancement. The voltage sensitivity of the Ca(2+)-currents was not affected by the algal toxin, and the toxin-induced currents were inhibited by 100 microM of the Ca(2+)-channel blocker D-600. In toxin-exposed cells microfluorometric measurements based on fura-2 revealed an increase of [Ca2+]i from 100-150 to 300-500 nM. This elevation was delayed and partially inhibited by 100 microM D-600. The algal toxin induced prolactin release in a dose-dependent manner, and this effect was inhibited by the Ca(2+)-channel blocker verapamil. We therefore conclude that the toxin of P. patelliferum affects the Ca2+ homeostasis of the pituitary cells by increasing the leak through voltage sensitive Ca(2+)-channels, resulting in increased [Ca2+]i and secretion of prolactin.

Animals↗
PubMed1996

Extract of the marine alga Prymnesium patelliferum induces release of acetylcholine from cholinergic nerves in the rat bronchial smooth muscle.

An extract of the marine algal flagellate Prymnesium patelliferum enhanced the spontaneous as well as the K+ evoked (51 mM K+) release of [3H]acetylcholine and endogenous acetylcholine from autonomic cholinergic nerves of rat bronchial smooth muscle. The effects were concentration-dependent and reversible. The enhancement of the K+ evoked release by the algal extract was partly dependent on extracellular Ca2+ and was significantly suppressed by the organic Ca2+ blockers omega-conotoxin GVIA (1 microM), diltiazem (100 microM), nifedipine (100 microM) and flunarizine (100 microM). The enhancement of the spontaneous release seemed Ca2+ independent and not sensitive to the Na+ channel blocker tetrodotoxin. Sphingosine (20 microM), a protein kinase C inhibitor, strongly potentiated the enhancement of spontaneous release of [3H]acetylcholine induced by the algal extract whereas another protein kinase C inhibitor. 1-(5-quinolinesulphonyl)-2-methylpiperazine (H-7) (20 microM), was without effect. A similar potentiation as seen with sphingosine was observed with procaine (100 microM) and flunarizine (100 microM). The results indicate that the enhancement of the K+ evoked release of [3H]acetylcholine by the toxic extract of P. patelliferum was partly caused by activation of voltage-dependent Ca2+ channels. The increase in the spontaneous release of [3H]acetylcholine and endogenous acetylcholine induced by the algal extract alone may be caused by an ionophore-like property of the algal extract. This effect of the algal extract may be enhanced by compounds that facilitate the interaction of the algal toxin with the plasma membrane such as the lipophilic compounds flunarizine, procaine and sphingosine.

Acetylcholine↗
PubMed1998

Dietary marine algae maintains egg consumer acceptability while enhancing yolk color.

A drum-dried docosahexaenoic acid (DHA; C22:6n-3) enriched marine microalgal product (MA) was investigated as a n-3 fatty acid (n-3 FA) source in laying hen diets. Hen diets were supplemented with 2.4 or 4.8% MA. Eggs were analyzed for yolk color following 4 wk of feeding as well as weekly for 4 wk. Egg flavor was evaluated by consumer panelists. Feeding MA significantly (P < 0.01) increased yolk a* values in a dose response manner as early as 1 wk post-MA feeding. Consumer panelists found n-3 FA enriched eggs as acceptable as typical eggs. These data suggest that dietary MA is useful for enhancing yolk n-3 FA and color while maintaining consumer acceptability of the resulting egg product.

Animal Feed↗
PubMed1995

Marine algae that display anti-tumorigenic activity against Agrobacterium tumefaciens.

Thirty-five extracts representing different seasonal growths of 17 marine algal species collected from the Alexandria coast were tested for anti-tumorigenic activity against Agrobacterium tumefaciens galls on potato discs. Eleven extracts (nine species) displayed > 20% inhibition of tumor initiation, with three of these (Codium tomentosum, winter; Jania rubens, summer; Padina pavonia, winter) displaying relatively high activity. Bacterial viability tests showed that the inhibitory effects were directly due to anti-tumorigenesis rather than an indirect result of anti-bacterial activity.

Agrobacterium tumefaciens↗
PubMed1988

Levels of zinc, cadmium and lead in some marine algae from Aqaba-Red Sea.

Jordan has witnessed a rapid industrial development in the last twenty years. This has lead to the release of waste materials or pollutants into the marine environment, particularly nearby Aqaba Port. The present study investigates the levels of zinc, cadmium and lead in four brown algae, three red algae and four green algal species collected from Aqaba. Three different levels of lead and zinc concentrations were found: the highest level of both metals is exhibited among brown algae; intermediate level is exhibited among red algae and the lowest level is seen among the green algae. Very low concentrations of cadmium were found in all examined algal species. The results indicate that the brown algal species Cystosira myrica, Sargassum asperifolium, Sargassum neglectum, and Sargassum subrepandum always contain the highest concentrations of lead and zinc, but these algae are less contaminated than brown algae from industrial European seas.

Cadmium↗
PubMed2006

Improved arsenic speciation analysis for extracts of commercially available edible marine algae using HPLC-ES-MS/MS.

Their increasing commercial availability and their rather high total arsenic contents necessitate a more detailed arsenic speciation analysis of marine algal products. Compared to current HPLC-ICPMS methods, HPLC on-line with electrospray tandem mass spectrometry in the selected reaction monitoring mode (HPLC-ES-SRM) offers much higher detection selectivity with similarly high sensitivity for most known organoarsenic species. This study demonstrates the advantages of HPLC-ES-SRM for the detection of the main as well as trace arsenic species in extracts of 12 commercially available marine algal powders. The main focus was the unambiguous identification of the detected arsenic species. Four quality control tools were applied for this purpose, including matching chromatographic retention times, comparing SRM transition ratios, recording product ion spectra, and determining accurate masses. As a result, evidence was obtained for the presence of 19 organoarsenic species in the analyzed algal extracts. The method of standard addition was used for quantification. Estimated matrix effects on the analyte signal were similar for most of the investigated arsenic species in extracts of different types of brown algae. This allowed the comparison of the contents of the arsenic species present in the 12 algal extracts on the basis of normalized peak areas. A partial correlation of the arsenic speciation pattern with the algal family or algal order, respectively, was found.

Arsenicals↗
PubMed2005

Refuge function of marine algae complicates selection in an intertidal snail.

Species with restricted gene flow often show trait-shifts from one type of environment to another. In those rock-dwelling marine gastropods that lack larval dispersal, size generally decreases in wave-exposed habitats reducing risk of dislodgement, while increases in less exposed habitats to resist crab-crushing. In Littorina fabalis, however, snails of moderately exposed shores are generally much larger (11-14 mm) than snails of sheltered shores (5-8 mm). Observations from the White Sea (where crabs are not present) indicate that in the absence of crabs snails are small (6-7 mm) in both habitats. We assumed that the optimal size for L. fabalis in the absence of crabs is less than 8 mm, and thus that increased size in moderately exposed habitats in areas with crabs might be a response to crab predation. In a crab-rich area (Sweden) we showed that crab predation is an important mortality factor for this snail species in both sheltered and moderately exposed habitats. In sheltered habitats, snails were relatively more protected from crab-predation when dwelling on their habitual substrate, fucoid algae, than if experimentally tethered to rocks below the algae. This showed that algae function as snail refuges. Snail dislodgement increased, however, with wave exposure but tethering snails in moderately exposed habitats showed that large snails survived equally well on rocks under the algae as in the canopy of the algae. Thus in sheltered habitats a small snail size is favored, probably due to life-history reasons, while increased risk of being dislodged from the algae refuges promotes a large size in moderately exposed habitats. This study shows an example of selection of a trait depends on complex interactions of different factors (life-history optimization, crab predation, wave induced dislodgement and algal refuges).

Analysis of Variance↗
PubMedDate not supplied

A five-year study of solar ultraviolet radiation in southern Chile (39 degrees S): potential impact on physiology of coastal marine algae?

This study reports 5 years of (1998-2003) data on continuous solar-irradiation measurements from a scanning spectroradiometer (SUV-100) in Valdivia, Chile (39 degrees S), accompanied by evaluation of the impact of ultraviolet radiation (UVR) on marine macroalgae of this site. UVR conditions showed a strong seasonal variation, which was less pronounced toward longer wavelengths. Daily maximum dose rates (clear days) averaged in winter-summer: UV-B(290-315 nm) 0.30-2.1, UV-B(290-320 nm) 0.70-3.7, UV-A(315-400 nm) 20.6-62.1, UV-A(320-400 nm) 20.2-60.5 W m(-2), and photosynthetically active radiation (PAR) 969-2423 micromol m(-2) s(-1). The corresponding daily doses (all the days) ranged: UV-B(290-315 nm) 2.6-40.7, UV-B(290-320 nm) 6.7-78.5, UV-A(315-400 nm) 228-1539, UV-A(320-400 nm) 224-1501, and PAR 2008-13308 kJ m(-2) d(-1). Taking into consideration action spectra of a biological interest, the risk of UV exposure could be up to 37 times higher in summer than in winter. The photosynthetic activity (as maximum quantum yield of chlorophyll fluorescence, F(v)/F(m)) of the brown alga Lessonia nigrescens from the infralittoral zone was markedly more sensitive to UVR than of the green alga Enteromorpha intestinalis from the upper midlittoral, and the UV-B wave band increased markedly photoinhibition. In L. nigrescens, maximal photoinhibition (40%) took place at weighted (the action spectrum for photoinhibition of photosynthesis) UVR doses of 800 kJ m(-2), irrespective of the season (corresponding midsummer daily dose in Valdivia is 480 kJ m(-2)). In winter, when this alga was at its most sensitive, the weighted UV dose causing 35-40% photoinhibition was around 200 kJ m(-2). In E. intestinalis, weighted doses of 800 kJ m(-2) resulted in low photoinhibition (<10 %) and no clear seasonal patterns could be inferred. These results confirm that midday summer levels of UV-B and their daily doses in southern Chile are high enough to produce stress to intertidal macroalgae.

Animals↗
PubMed2002

Influence of N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid pH buffer on the biological response of marine algae.

The N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES) is extensively used as pH buffer in culture media for testing chemicals. However, this study demonstrates that 0.01 M HEPES significantly reduces the rate of Cu, Pb, and Cd binding to Porphyra spp. and Enteromorpha spp. marine macroalgae. The HEPES also decreased the accumulation of Cu, Pb, and Cd but not Hg by these macroalgae. Both the extracellular adsorption and the intracellular uptake of the metals were influenced by HEPES to a similar extent. The HEPES also promoted the release of exudates by the algae, and these exudates form very stable complexes with Cu (and probably with other trace metal ions). The HEPES interference varied with the nature of the metal, the macroalga, and the season. The presence of 0.01 M HEPES in seawater cultures of the Emiliania huxleyi (a microalga) also interfered with E. huxleyi growth, liberation of Cu-complexing organic ligands, and Cu uptake. The HEPES, which displays surface activity, may facilitate the binding of metals to the algae for an initial exposure period. The metal taken up appears to stimulate the liberation of exudates that subsequently control the bioavailability of the metals and therefore metal uptake. Because HEPES can control the uptake of trace metals by algae and the production of organic ligands, the results obtained in cultures containing the HEPES pH buffer can be influenced by this component of the media.

Biological Availability↗
PubMed2004

Laurenditerpenol, a new diterpene from the tropical marine alga Laurenciaintricata that potently inhibits HIF-1 mediated hypoxic signaling in breast tumor cells.

The degree of tumor hypoxia correlates with advanced disease stages and treatment resistance. The transcription factor hypoxia-inducible factor-1 (HIF-1) promotes tumor cell adaptation and survival under hypoxic conditions. Therefore, specific HIF-1 inhibitors represent an important new class of potential tumor-selective therapeutic agents. A T47D human breast tumor cell-based reporter assay was used to examine extracts of plants and marine organisms for inhibitors of HIF-1 activation. Bioassay-guided fractionation of the lipid extract of the red alga Laurencia intricata yielded a structurally novel diterpene, laurenditerpenol (1). The structure of 1 was determined spectroscopically. The relative configurations of the substituents of each ring system were assigned on the basis of NOESY correlations. The absolute configuration of position C-1 was determined by the modified Mosher ester procedure (directly in NMR tubes). Compound 1 potently inhibited hypoxia-activated HIF-1 (IC50: 0.4 microM) and hypoxia-induced VEGF (a potent angiogenic factor) in T47D cells. Compound 1 selectively inhibits HIF-1 activation by hypoxia but not iron chelator-induced activation. Further, 1 suppresses tumor cell survival under hypoxic conditions without affecting normoxic cell growth. Compound 1 inhibits HIF-1 by blocking the induction of the oxygen-regulated HIF-1alpha protein. Mitochondrial respiration studies revealed that 1 suppresses oxygen consumption.

Antineoplastic Agents↗
PubMed1979

[Anti-inflammatory action of extracts from marine algae collected in the area of Burgas seacoast].

It was established by a series of experiments with white Wistar rats that intraperitoneal injection of water extracts (infusions) of a mixed sample of dried algae (Cystosira barbata, Ulva lactica and Zostera nona) collected at the Bourgas coastal region, respectively leveled to an isotonic solution by use of 0.9% NaCl produces well expressed antiinflammatory effect in Caragina provoked oedema. The mixed sample of algae has LD0--0.250 g dry drug per kg body weight, LD'100--0.500 g/kg b. w. and LD50--0.407 g/kg b. w. The therapeutic index of the algae is relatively high -- LD50/U50+20.

Animals↗