FAT-SOLUBLE VITAMINS AND BIOLOGICAL MEMBRANES

Perceiving the functions of vitamin E through neutron and X-ray scattering

Take your vitamins, or don't? Vitamin E is one of the few lipophilic vitamins in the human diet and is considered an essential nutrient. Over the years it has proven to be a powerful antioxidant and is commercially used as such, but this association is far from linear in physiology. It is increasingly more likely that vitamin E has multiple legitimate biological roles. Here, we review past and current work using neutron and X-ray scattering to elucidate the influence of vitamin E on key features of model membranes that can translate to the biological function(s) of vitamin E. Although progress is being made, the hundred year-old mystery remains unsolved.

Cold pressed Pinus halepensis Mill. seed oil for potential health applications: Analgesic, anti-inflammatory effects, and assessment of inflammatory mediators by RT-qPCR in skin wound healing

ETHNOPHARMACOLOGICAL RELEVANCE

Pinus halepensis Mill. seed (Pinaceae), commonly known as "Zgougou," is widely consumed in the Mediterranean region and has long been used to treat diseases including bronchitis, rheumatism, infection, and inflammation.

AIM OF THE STUDY

The present study was focused on the investigation of some pharmacological activities, such as analgesic, anti-inflammatory, and wound healing effects, of cold-pressed oil of Pinus halepensis Mill. seed (COPHS).

MATERIALS AND METHODS

The fixed oil of Pinus halepensis seed was extracted by a cold pressing process. The analgesic activity of COPHS was examined by acetic acid and formalin-induced contortion and pain tests. The anti-inflammatory effects were evaluated in carrageenan and formalin induced paw and ear edema models. Wound healing potential was assessed on an experimental skin wound, and the expression levels of inflammation mediators were determined by RT-qPCR in skin wound healing.

RESULTS

The results showed analgesic efficacy through significant inhibition of abdominal cramps (59.15%) and pain (75.91%). In addition, this oil exerted an anti-inflammatory effect by inhibiting ear (62.25%) and paw (70.00%) edema. The COPHS stimulated wound contraction in experimental skin wound healing with a contraction rate of 89.23% with notable reduction of TNF-α and NF-kB expression levels in the treated groups.

CONCLUSIONS

This study provided for the first time the pharmacological profile, particularly the analgesic, anti-inflammatory, and healing effects, of fixed oil extracted by cold pressing from the seed of Pinus halepensis Mill.

Photosynthetic microorganisms and their bioactive molecules as new product to healing wounds

Wounds are a public health problem due to long periods required to repair damaged skin, risk of infection, and amputations. Thus, there is a need to obtain new therapeutic agents with less side effects, more effective oxygen delivery, and increased epithelial cell migration. Photosynthetic microorganisms, such as microalgae and cyanobacteria, may be used as a source of biomolecules for the treatment of different injuries. The aim of this review article focuses on healing potential using phytoconstituents from photosynthetic microorganisms. Cyanophyte Spirulina and Chlorophyte Chlorella are more promising due to steroids, triterpenes, carbohydrates, phenols, and proteins such as lectins and phycocyanin. However, there are few reports about identification and specific function of these molecules on the skin. In other microalgae and cyanobacteria genus, high contents of pigments such as β-carotene, chlorophyll a, allophycocyanin, and hydroxypheophytin were detected, but their effects on phases of wound healing is absent yet. The development of new topical drugs from photosynthetic microorganisms could be a potential alternative to maximize healing. KEY POINTS: • Conventional treatment to skin injuries has limitations. • Proteins, terpenes, and phenols increase collagen deposition and re-epithelialization. • Microalgae and cyanobacteria may be used as a source of biomolecules to wound healing.

From fat to bilayers: Understanding where and how vitamin E works

Vitamin E was one of the last fat-soluble vitamins to be discovered. We provide here an historical review of the discovery and the increasingly more detailed understanding of the role of α-tocopherol both as an antioxidant and as a structural component of phospholipid bilayer membranes. Despite the detailed descriptions now available of the orientation, location, and dynamics of α-tocopherol in lipid bilayers, there are still gaps in our knowledge of the effect of α-tocopherol and its potential receptors than control gene transcription.

In Search for the Membrane Regulators of Archaea

Membrane regulators such as sterols and hopanoids play a major role in the physiological and physicochemical adaptation of the different plasmic membranes in Eukarya and Bacteria. They are key to the functionalization and the spatialization of the membrane, and therefore indispensable for the cell cycle. No archaeon has been found to be able to synthesize sterols or hopanoids to date. They also lack homologs of the genes responsible for the synthesis of these membrane regulators. Due to their divergent membrane lipid composition, the question whether archaea require membrane regulators, and if so, what is their nature, remains open. In this review, we review evidence for the existence of membrane regulators in Archaea, and propose tentative location and biological functions. It is likely that no membrane regulator is shared by all archaea, but that they may use different polyterpenes, such as carotenoids, polyprenols, quinones and apolar polyisoprenoids, in response to specific stressors or physiological needs.

Evaluation of Wound Healing Properties of Grape Seed, Sesame, and Fenugreek Oils

Background. Medicinal plants have proved at all times to be a powerful remedy for health care. Accordingly, grape seed, sesame, and fenugreek extracted oils with pharmacological properties are investigated as wound treatments. This study assesses the potential of our oils for healing wounds induced on rats. Methods. Phytochemical analyses of oils have involved: quality value, polyphenol, chlorophylls, carotene, and fatty acids. Antibacterial activity was carried out. Antioxidant activity was evaluated: the scavenging effect on DPPH radicals, the reducing power, and β-carotene discoloration. Uniform wound excision was induced on rats dorsum randomly divided into five groups: groups treated with "CICAFLORA®" and tested oils and untreated one. The posthealing biopsies were histologically assessed. Results. Wound biopsies treated with oils showed the best tissue regeneration compared to control groups. Groups treated with our oils and "CICAFLORA" had higher wound contraction percentage. Polyunsaturated fatty acids in oils act as inflammatory mediators increasing neovascularization, extracellular remodeling, migration, and cell differentiation. Wound healing effect was attributed to antibacterial and antioxidant synergy. Conclusion. According to findings, oils showed better activity in wound healing compared to "CICAFLORA" due to a phytoconstituents synergy. However, clinical trials on humans are necessary to confirm efficacy on human pathology.

The protective effect of vitamin E against changes in fatty acid composition of phospholipid subclasses in gill tissue of Oreochromis niloticus exposed to deltamethrin

The effects of deltamethrin on the fatty acid composition of phospholipid subclasses (phosphatidylchlonine (PC), phosphatidylethanolamine (PE), phosphatidylinositole (PI) and phosphatidylserine (PS)) in gill tissue of Oreochromis niloticus (Perciformes: Cichlidae) and the possible protective effect of vitamin E against deltamethrin were determined by gas chromatography. The changes in the fatty acid profile were analysed after 14 d of exposure. Treatments included Group I (fed with basal diet only), Group II (fed with vitamin E-supplemented diet), Group III (fed with basal diet and exposed to deltamethrin) and Group IV (fed with vitamin E-supplemented diet and exposed to deltamethrin). The effects of deltamethrin on PI, PE and PS were valid for the total saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs). The effect on PC was detected in total SFAs and total PUFAs. The vitamin E-supplemented diet did not show complete protective effect on fatty acid composition of the fish exposed to deltamethrin. However, the protective effect was observed in total SFAs, total MUFAs and total PUFAs in PC. In PI, protective effect was only recorded on total PUFAs. There was no protective effect in PS and PE. The results of the present study demonstrated that deltametrin exposure had harmful effects on cell membrane and treatment with vitamin E could only partially protect fish gills.

The protective role of vitamin E on gill and liver tissue histopathology and micronucleus frequencies in peripheral erythrocytes of Oreochromis niloticus exposed to deltamethrin

Deltamethrin, is a commonly used pyrethroid pesticide. Vitamin E is a antioxidant that plays an important role in protecting cells against toxicity by inactivating free radicals generated following pesticides exposure. Therefore, it was evaluated whether deltamethrin induced histopathological changes and nuclear abnormalities using micronucleus test in Oreochromis niloticus, and the possible protective effect of vitamin E against deltamethrin inducing adverse effects in O. niloticus were investigated. Fish was fed with no pesticide+control diet, no pesticide+vitamin E-supplemented diet, 1.45μg/l deltamethrin+control diet, 1.45μg/l deltamethrin+vitamin E-supplemented diet for 30 days. Pesticide and diet quality made an impact on histopathological lesions. In treatments of deltamethrin, group fed with control diet showed much greater damage in comparison with group fed with vitamin E supplemented diet. Vitamin E decreased some histopathological changes induced by deltamethrin, but did not confer complete protection. Deltamethrin treatment has been shown to results in a significant increase in the frequency of micronucleus. However, coadministration of deltamethrin and vitamin E showed decrease in the frequency of micronucleus as compared to deltamethrin treated fish. Our results indicate that, the MN assay and histopathology can be used as bioassays for monitoring pollution in aquatic medium. On the other hand, it was observed that vitamin E decreased the genotoxicity and histopathological changes induced by deltamethrin.

The protective role of vitamin E on the fatty acid composition of phospholipid structure in gill and liver tissues of Oreochromis niloticus exposed to deltamethrin

Deltamethrin is a commonly used pyrethroid pesticide. Vitamin E is a antioxidant that plays an important role in protecting cells against toxicity by inactivating free radicals generated following pesticides exposure. Therefore, in the present study, it was evaluated whether deltamethrin induced changes on the fatty acid composition of phospholipid in gill and liver tissues in Oreochromis niloticus and, the possible protective effect of vitamin E against deltamethrin was determined. Fish was fed with no pesticide+control diet, no pesticide+vitamin E-supplemented diet, 1.45 μg/l deltamethrin+control diet, 1.45 μg/l deltamethrin+vitamin E-supplemented diet for twenty days. Pesticide and diet quality made an impact on the fatty acid composition of phospholipid. In treatments of deltamethrin, group fed with control diet showed much greater damage in comparison with group fed with vitamin E supplemented diet. The results indicated that the deltamethrin led to an increase in the percentages of total SFAs (saturated fatty acids) and total MUFAs (monounsaturated fatty acids) and a decrease in total PUFAs (polyunsaturated fatty acids) in the gill tissues. However, coadministration of deltamethrin and vitamin E showed decrease in the percentages of saturated fatty acids and increase in the percentages of polyunsaturated fatty acids in the gill tissues. In group fed with control diet, deltamethrin led to a decrease in the percentage of SFAs and a increase in total MUFAs in the liver. Coadministration of deltamethrin and vitamin E showed increase in the percentages of polyunsaturated fatty acids in the liver tissues. These results have demonstrated that administration of vitamin E along with deltamethrin decreases the peroxidation of unsaturated fatty acids and thus protects the cell membranes.

Theory of the origin, evolution, and nature of life

Life is an inordinately complex unsolved puzzle. Despite significant theoretical progress, experimental anomalies, paradoxes, and enigmas have revealed paradigmatic limitations. Thus, the advancement of scientific understanding requires new models that resolve fundamental problems. Here, I present a theoretical framework that economically fits evidence accumulated from examinations of life. This theory is based upon a straightforward and non-mathematical core model and proposes unique yet empirically consistent explanations for major phenomena including, but not limited to, quantum gravity, phase transitions of water, why living systems are predominantly CHNOPS (carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur), homochirality of sugars and amino acids, homeoviscous adaptation, triplet code, and DNA mutations. The theoretical framework unifies the macrocosmic and microcosmic realms, validates predicted laws of nature, and solves the puzzle of the origin and evolution of cellular life in the universe.

Incorporation of vitamin E in poly(3hydroxybutyrate)/Bioglass composite films: effect on surface properties and cell attachment

This study investigated the possibility of incorporating alpha-tocopherol (vitamin E) into poly(3hydroxybutyrate) (P(3HB))/Bioglass composites, which are being developed for bone tissue engineering matrices. P(3HB) films with 20 wt% Bioglass and 10 wt% vitamin E were prepared using the solvent casting technique. Addition of vitamin E significantly improved the hydrophilicity of the composites along with increasing the total protein adsorption. The presence of protein adsorbed on the composite surface was further confirmed using X-ray photoelectron spectroscopy analysis. Preliminary cell culture studies using MG-63 human osteoblasts showed that the addition of vitamin E in the P(3HB)/20 wt% Bioglass films significantly increased cell proliferation. The results achieved in this study confirmed the possibility of incorporating vitamin E as a suitable additive in P(3HB)/Bioglass composites to engineer the surface of the composites by promoting higher protein adsorption and increasing the hydrophilicity.

The effect of resveratrol on surgery-induced peritoneal adhesions in an experimental model

Adhesion formation is a common cause of complications following surgery. The aim of this study was to investigate the effect of resveratrol on intra-abdominal adhesion prevention in a rat model. Twenty one Wistar-Albino rats weighing 200-250 g were assigned to three groups, of 7 rats each. After a midline laparotomy was performed, a 1 cm area of the ceacum was abraded in two of the groups. They were then given either resveratrol (Group 1), or saline (Group 2) intraperitoneally. Group 3 rats (sham operation) received no treatment, without the serosal damage. On the 14th day, the rats were killed and the adhesion score was determined according to Mazuji's adhesion grade scale. The tissue levels of malondialdehyde (MDA), nitric oxide (NO), and reduced glutathione (GSH) were measured. The mean Mazuji's adhesion grade in the resveratrol group was 1.0 +/- 0.0, in the saline group 2.57 +/- 1.51, and zero in the sham operated group (p < 0.05 between the resveratrol group and saline group comparison). The levels of MDA and NO in the resveratrol group were significantly lower than those of the saline group (p < 0.001). The level of GSH in the resveratrol group was significantly higher than in the saline and sham operated groups (p < 0.001 and p < 0.001, respectively). Introduction of resveratrol into the peritoneal cavity at the time of surgery reduced adhesion formation effectively in this model. Resveratrol probably acts through reduction of lipid peroxidation products.

The effect of vitamin A deficiency and dietary alpha-tocopherol on the stability of rat-liver lysosomes

1. Vitamin A-deficient rats and pair-fed controls were maintained on either normal or raised amounts of dietary alpha-tocopherol. 2. Their livers were fractionated and ;free' and ;total' lysosomal phosphatase were determined in the various fractions. The rate of release of this enzyme was determined in the mitochondria-lysosome-rich fraction during incubation at pH5 and 37 degrees . 3. The deficient livers showed increased enzymic activity. 4. Prolonged incubation caused more rapid enzyme release from the mitochondria-lysosome-rich fraction of the vitamin A-deficient rats receiving the normal amount of dietary alpha-tocopherol than from the equivalent fraction of their pair-fed controls receiving vitamin A. Raised dietary alpha-tocopherol reversed this phenomenon.

Characterization of the effect of retinol on Plasmodium falciparum in vitro

A preliminary study from our laboratory found retinol (vitamin A alcohol) to have in vitro activity against Plasmodium falciparum at concentrations close to those in normal human serum (1-3 microM). To characterize the antimalarial potential of retinol in more detail, the 3D7 and K1 laboratory strains of P. falciparum were maintained in continuous culture and [3H]hypoxanthine incorporation and microscopy were used to assess the effect of retinol against asexual stages of the parasite life-cycle. Losses of retinol and retinol-associated hemolysis were also quantified in the in vitro culture system. There were retinol losses of >50% but no hemolysis was observed with added retinol concentrations up to 100 microM. All stages of parasite development showed comparable sensitivity to retinol including merozoite invasion (range of mean IC50 values 10.1-21.4 microM after adjustment for losses). Retinol pre-treatment of uninfected RBC did not inhibit merozoite invasion. Retinol treatment was associated with increased vacuolization within the parasite food vacuole and evidence of parasite membrane rupture. These appearances were similar to those seen with quinoline and artemisinin compounds. Although these data do not support a role for acute retinol supplementation in the treatment of falciparum malaria, they add to knowledge regarding potential antimalarial therapies and justify assessment of more potent synthetic retinoids and their metabolites.

New acrylic bone cements conjugated to vitamin E: curing parameters, properties, and biocompatibility

Acrylic bone cement formulations with antioxidant character were prepared by incorporation of a methacrylic monomer derived from vitamin E (MVE). Increasing concentrations of this monomer provided decreasing peak temperature values, ranging from 62 to 36 degrees C, and increasing setting time with values between 17 and 25 min. Mechanical properties were evaluated by compression and tension tests. Compressive strength of the new formulations were superior to 70 MPa in all cases. The cement containing 25 wt % MVE, however, showed a significant decrease in tensile properties. Biocompatibility of the new formulations was studied in vitro. The analysis of the effect of leachables from cements into the media showed continued cell proliferation and cell viability with a significant increase for the cement containing 15 wt % MVE. This formulation also showed a significant increase in cellular proliferation over a period of 7 days as indicated by the Alamar Blue test. The cells were able to differentiate and express phenotypical markers in presence of all materials. A significant increase in alkaline phosphatase activity was observed on the cements prepared in presence of 15-25 wt % MVE compared with PMMA. Morphological assessment showed that the human osteoblast (HOB) cells were able to adhere, retain their morphology, and proliferate on all the cements.

Increased systemic oxidative stress after elective endarterectomy: relation to vascular healing and remodeling

It has been reported that systemic and local redox state may have an important role in the functional and organic changes characterizing the process of vascular response to injury. Carotid endarterectomy to remove atherosclerotic plaque is followed by a long lasting healing and remodeling process that can be carefully followed over time with noninvasive ultrasonography. Plasma vitamin C concentration and native LDL (n-LDL) content in lipid peroxides, vitamin E, beta-carotene, and lycopene as well as LDL susceptibility to peroxidation were assessed in 45 patients undergoing elective endarterectomy for internal carotid stenosis, at baseline, 24 hours, 3 and 15 days, and 1 month after surgery. Serial duplex scans were performed in all patients postoperatively and 3, 6, and 12 months. The changes in far wall thickness (FW) and % renarrowing from postoperatively to 12 months were used as remodeling indices. Plasma antioxidant vitamins and lag-phase showed a sharp and significant decrease during the first 24-hours after surgery remaining unchanged until the third day, whereas, an opposite trend was evidenced for n-LDL content in lipid peroxides and serum ceruloplasmin. After the third day all the parameters returned progressively to baseline within one month from endarterectomy. Interestingly, the n-LDL lipid peroxide content, the serum ceruloplasmin and the plasma vitamin C concentration, measured at 24 and 3 days from surgery, were significantly associated to the change in % renarrowing from postoperatively to 12 months. The higher the LDL content in lipid peroxides, the higher the serum level of ceruloplasmin, the lower the plasma content in vitamin C and the higher the % of vessel renarrowing. In conclusion, carotid endarterectomy with atherosclerotic plaque removal is associated with an acute and prolonged increase in systemic oxidative stress that influences vascular healing and late luminal loss.

beta-carotene as a high-potency antioxidant to prevent the formation of phospholipid hydroperoxides in red blood cells of mice

In order to investigate the antioxidant effect of beta-carotene in vivo, phospholipid hydroperoxides and beta-carotene isomers in red blood cells (RBC), plasma and tissue organelles were quantitatively measured after the oral administration of beta-carotene (94.8% all-trans-beta-carotene) to mice. Three groups of 24 mice each were fed for 1 week on a semisynthetic diet supplemented with either 0.6% or 3.0% beta-carotene/diet or maintained on a control (beta-carotene-unsupplemented) diet. The RBC phospholipid hydroperoxides showed a significant decrease followed by an increase of beta-carotene intakes; i.e., 201, 16 and 4 pmol of phosphatidylcholine hydroperoxide/ml packed RBC, and 108, 22 and 8 pmol of phosphatidylethanolamine hydroperoxide/ml packed RBC, in the mice given the control diet, 0.6% carotene diet and 3.0% carotene diet, respectively. The RBC beta-carotene increased from 14 to 43 pmol/ml packed RBC as followed by the increase of beta-carotene intakes. Such a potent antioxidant effect of beta-carotene as observed in RBC was not confirmed in the plasma, liver or lungs, although their beta-carotene contents increased. The beta-carotene ingestion increased the all-trans-beta-carotene and retinol contents in RBC, plasma, liver and lungs, but the alpha-tocopherol content decreased. In the beta-carotene-supplemented (6 g and 30 g/kg diet) mice, cis-beta-carotene content was relatively higher in the RBC (25-35% of total beta-carotene) than that in the plasma, liver and lungs. The present findings indicate that not only does beta-carotene act as a potent antioxidant in vivo but also its antioxidant effect is very specific in the RBC phospholipid bilayers rather than in the plasma and other tissue organelles.

Age-dependent survival-promoting activity of vitamin K on cultured CNS neurons

Neurons from the central nervous system (CNS) of rat embryos die within several days when seeded at a low density of 10(4) cells/cm2 and cultured in a serum-free defined medium. Using these culture systems, we searched for agents to promote the survival of these neurons. As a consequence, a fat-soluble vitamin, vitamin K1, was found to possess such kind of activity: more than 50% of the cortical neurons from 19-day-old rat embryos could survive for 4 days in the presence of vitamin K1, whereas almost all neurons died in its absence. The survival-promoting effect of vitamin K1 was found on neurons from not only cortex, but also hippocampus, striatum, and septum. In addition to vitamin K1, vitamin K2 and K3 also showed the same effect on cortical neurons. The effect of vitamins K1 and K2 was observed at concentrations from 10(-8) to 10(-6) M, and that of vitamin K3 was slightly detected at 10(-6) M. Furthermore, we examined the effect on the neurons from 16- and 21-day-old embryos, too. The activity of vitamin K1 was weaker toward the neurons from 21-day-old embryos compared with that toward 19-day-old ones, and was not recognized toward 16-day-old ones. These results suggest the potential role of the K vitamins on the maintenance of the survival of CNS neurons during the later stages of embryogenesis in vivo.

Intracellular actions of vitamin A

Because the effects of vitamin A vary with tissue type and often with the form of vitamin A itself, a complete understanding of the mechanism(s) of action still has not been attained. The action of vitamin A may be at the level of genomic expression, at the membrane level, or both. Intercellular and intracellular transport of vitamin A are facilitated by specific binding proteins but probably not in the cellular uptake of vitamin A. Subcellularly, vitamin A may exert a direct effect on transit through the Golgi apparatus, as observed from both biochemical and morphological studies. In my laboratory, recent work using cell-free systems has shown that retinol stimulates transition vesicle formation from endoplasmic reticulum in a GTP-requiring step.

Deuterium NMR study of the interaction of phytanic acid and phytol with the head group region of a phospholipid bilayer. Evidence of magnetic orientation

Deuterium nuclear magnetic resonance (2H-NMR) spectra of multilamellar dispersions of 1,2-dipalmitoyl-sn-glycero-3-phospho-[1',2'-methylene-2H4]choline (DPPC-d4) containing 20 mol% of the isoprenoid compounds phytol or phytanic acid in excess deuterium-depleted water, or Tris buffer (pH 7.4), have been recorded over the temperature range 15-55 degrees C. Phytol (20 mol%) causes a decrease in the residual quadrupolar splitting, delta vQ, of the choline 1'-deuterons (i.e., those adjacent to the phosphate moiety) by 3%, while delta vQ, of the 2'-deuterons decrease by 22%. Phytanic acid (20 mol%) reduces delta vQ of the 2'-deuterons by 43% and increases delta vQ of the 1'-deuterons by approx. 16%. First (M1) and second (M2) moments were calculated from the spectra. Plots of M1 and M2 versus temperature suggest phytol and phytanic acid have a significant effect on the pretransition. Spin-lattice relaxation times (T1) and transverse relaxation times (T2e, the time constant for decay of the quadrupolar echo) have been determined over the temperature range 15-50 degrees C. The presence of 20 mol% phytanic acid results in orientation of the DPPC bilayers in the magnetic field with the phospholipid long axes oriented perpendicular to the magnetic field as shown by 2H- and 31P-NMR. The sample must be carried through several freeze-thaw cycles in the presence of Tris buffer in order that the phospholipid magnetic field ordering occur. Possible explanations for the effect of phytol and phytanic acid on the dynamic structure of the choline head group of phospholipids in the bilayer are suggested.

Carcinogenesis induced by black pepper (Piper nigrum) and modulated by vitamin A

Painting and feeding of mice with 2mg of an extract from black pepper on 3 days a week for 3 months results in a significant increase of the number of tumor-bearing mice. Tumor incidence is reduced in those groups of experimental animals receiving 5 or 10mg Vitamin A-palmitate twice weekly for 3 months by feeding or painting during and subsequent to application of pepper extract. Feeding of mice with powder of black pepper in diet (50g/3kg food) has no impact on carcinogenesis.

Experimental craniofacial malformations induced by retinoids and resembling branchial arch syndromes

A syndrome which showed similarities to human branchial arch syndromes could be induced in Sprague-Dawley rat embryos by exposing them to retinoids prenatally. Treatment of pregnant rats with 40 mg/kg retinoic acid or 10 mg/kg etretinate on pregnancy day 8.5-9 resulted in craniofacial defects in 100% of the embryos. A scanning electron microscopic investigation of the early stages in the development of these malformations showed abnormal skull form, disorganised surface epithelium with "cell blebbing", lateral facial clefts, facial fistulas, narrowed skull-base and reduced size of the nasal and maxillary complexes. Histological examination confirmed these findings and supported the hypothesis that a main reason for this syndrome is hindrance of migration of the cranial neural crest cells to the facial processes during early craniofacial formation.

Regulatory role of retinoic acid on cultured mouse keratinocyte inositol phospholipid metabolism: dose-dependent release of inositol triphosphate

The incorporation of precursor 14C-myoinositol into the three cellular inositol phospholipids (PtdIns, PtdInsP, and PtdInsP2) of cultured, rapidly proliferating keratinocytes is significantly enhanced by the exogenous addition of a high concentration (1 X 10(-7) M) of all-trans retinoic acid or its analog 13-Cis analog, whereas a similar incubation with a low concentration (1 X 10(-10) M) of the same retinoid resulted in an insignificant incorporation of the radio-precursor into the three inositol phospholipids. Incorporation was most marked into the more phosphorylated PtdIns4P and PtdIns4,5P2. These results indicate that retinoic acid affects the biosynthesis of the inositol phospholipids at high concentrations. In contrast, the hydrolysis of 14C-PtdIns4,5P2 and release of 14C-InsP3 from the prelabeled keratinocytes is markedly enhanced by a low physiologic concentration (1 X 10(-10) M) of retinoic acid or its 13-Cis analog. The hydrolysis is rapid, with an accompanying elevated transient release of 14C-InsP3. High concentration (1 X 10(-5) M), on the other hand, supresses 14C-InsP3 release. These results taken together underscore a bifunctional, dose-dependent effect of both the all-trans-RA and its 13-Cis analog on the synthesis and hydrolysis of keratinocyte PtdIns4,5P2. Furthermore, the results suggest that at low physiologic concentrations, these retinoids may function as agonists to perturb the membrane resulting in induced rapid hydrolysis of cellular PtdIns4,5P2, which is coupled to a "transient" generation of InsP3 (an intracellular second messenger). The rapid formation of this putative "second messenger" may in turn play a role in the cellular proliferative or differentiating biochemical events in the murine keratinocytes.

Inhibition of Ca2+-induced cytosolic enzyme efflux from skeletal muscle by vitamin E and related compounds

1. Efflux of an intracellular enzyme (creatine kinase) from normal rat skeletal muscles was induced by treatment with the Ca2+ ionophore A23187. Addition of alpha-tocopherol (230 microM) to the incubation medium was found to significantly diminish this efflux, and this effect was mimicked by alpha-tocopherol acetate, phytol and isophytol, but not by Trolox C (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid). 2. Analysis of muscle cation content has shown that these protective effects of alpha-tocopherol etc. are not due to an inhibition of the Ca2+ accumulating effects of the ionophore. 3. Non-enzymic lipid peroxidation of skeletal-muscle homogenates was found to be inhibited by alpha-tocopherol and Trolox C, partially inhibited by phytol and isophytol, but unaffected by alpha-tocopherol acetate. 4. The activity of lipoxygenase enzymes was partially inhibited by alpha-tocopherol, phytol and isophytol, but not by alpha-tocopherol acetate or Trolox C. 5. Prostaglandin E2 efflux from isolated skeletal muscles was stimulated by treatment with the Ca2+ ionophore, but this was unaffected by alpha-tocopherol treatment.

Physiological antioxidants and antioxidative enzymes in vitamin E-deficient rats

The effects of feeding vitamin E-deficient diets to rats for one year were investigated to analyse the relationship of the vitamin with other antioxidants and some antioxidative enzymes. Long-term vitamin E deficiency lowered the levels of antioxidants like vitamin E, ascorbic acid and glutathione (GSH) in all tissues analysed and thus increasing the extent of tissue peroxidisability. Vitamin E deficiency had also influenced the activities of superoxide dismutase (SOD), catalase and glutathione peroxidase, the enzymes that are involved in detoxification mechanisms of products arising from free radical metabolism.

Potentiation of vincristine by vitamin A against drug-resistant mouse leukaemia cells

Vitamin A has been shown to potentiate the cytotoxic action of anticancer agents like vincristine (VCR) against drug resistant mouse P388 leukaemia cells. In vitro tests showed enhancement by retinyl acetate of cytocidal activities of VCR against drug-sensitive leukaemia (P388/S) and VCR-resistant leukaemia (P388/VCR) cells in culture; retinyl acetate rather specifically potentiated VCR against cultured P388/VCR cells than P388/S cells. The cellular accumulation of radioactive VCR was significantly enhanced in cultured P388/VCR cells when retinyl acetate was present. The efflux of VCR from drug-resistant cells was blocked by retinyl acetate. The effect of the combination of vitamin A and VCR was also tested in vivo on the life-span of mice bearing P388/S or P388/VCR. Intraperitoneal administration of retinyl palmitate at 41.75 or 83.5 mg kg-1 was effective to potentiate the antileukaemic activity of VCR against P388/S bearing mice, and it also overcame vincristine-resistance in P388/VCR bearing mice.

An assessment of the safety of tocopherols as food additives

This paper is a critical review of data relevant to the safety of tocopherols as food additives. Tocopherols are considered from the standpoint of their chemical-physical properties, occurrence in nature and use in commercial products. Dietary intake and kinetic and metabolic data, as well as biological activity and interactions with other vitamins, are also examined. The subjects discussed include acute, subchronic and chronic toxicity data, reproduction and teratogenesis studies, and observations in humans following high intakes of tocopherols. On the basis of the comprehensive experimental and clinical data available on alpha-tocopherol, the chemical and biological similarity of the alpha-, beta-, gamma- and delta-tocopherols and the information available on the levels of tocopherols used as food antioxidants, it is concluded that tocopherols are safe food additives.

Radiobiologic response of CHO-KI cells treated with vitamin A

Treatment of CHO-KI cells with vitamin A altered their response to subsequent gamma irradiation. In general longterm preincubation with low doses of the vitamin caused a relative increase in the number of cells surviving a given radiation dose. The effect resulted in an increase in the D0 of the survival curve. Long or short term exposure to high concentrations of the vitamin caused a decrease in the number of surviving cells leading to a decrease in the extrapolation number of the survival curve. Recovery of cells from radiation damage, assessed using the split dose technique, was also impaired by vitamin A pretreatment. A mechanism involving repair of potentially lethal damage may explain the protective effect of vitamin A since this was highly dependent on the cell density of cultures at the time of irradiation. However, in view of the data showing that the vitamin A concentrations necessary to alter the radiation survival curve shoulder caused a significant release of sialic acid into the medium, a mechanism involving membrane stability may account for both the reduction in repair/recovery capacity of the treated cells and the radioprotective effect.

Inhibition of cutaneous paresthesia resulting from synthetic pyrethroid exposure

Synthetic pyrethroids are potent lipophilic insecticides recognized as nerve toxins. Their increased usage in recent years has established them as a serious competitor against the currently available pesticides. Reported cases of occupational exposure have noted the presence of paresthesia without the clinical symptoms of erythema, edema, or vesiculation. Pilot studies were performed with six prophylactic agents to assess their capability of preventing or ameliorating the paresthesia that accompanies exposure. Vitamin E oil (dl-alpha tocopheryl acetate) proved the most efficacious.

Protective effect of 4-(3,7,11,15-tetramethyl-6,10,14-hexadecatrienoyl)morpholine on liver injury induced by hepatotoxins in rats

The effect of 4-(3,7,11,15-tetramethyl-6,10,14-hexadecatrienoyl)morpholine (E-0712), a new synthetic compound, on liver injury induced by two hepatotoxins in rats was studied. Oral doses of E-0712 four times at 0, 6, 12 and 18 hr significantly attenuated elevated SGPT values and prolonged prothrombin time (PT) at 24, 36, 48, 60 and 72 hr in rats with a single s.c. dose of D-galactosamine in which SGPT values and PT reached the peak within 48 hr. In cases in which a dose of carbon tetrachloride (i.p.) produced peak SGPT values and PT within 36 hr attenuation occurred likewise at 24, 36 and 60 hr. In the control and E-0712-treated rats dosed with D-galactosamine or carbon tetrachloride, SGPT values were positively correlated with PT at 24 hr. In addition, morphological degrees of acidophilic body formation or centrizonal necrosis were significantly reduced by E-0712. These results suggest that E-0712 protects against liver injury, particularly hepatocellular necrosis, induced by D-galactosamine and carbon tetrachloride in rats.

Retinoic acid alters subcellular compartmentalization of ATP pools in 3T3 cells but not in HeLa cells

Retinoic acid (RA; beta-all-trans) inhibits the proliferation of both murine 3T3 cells and human HeLa cells. Flow cytometric analyses of exponentially growing cultures show that 3T3 cells are inhibited during the S phase of their cell cycle, while HeLa cells show only a small increase in G1 phase cells. RA (10 microM) causes a 50% increase in total cellular adenosine triphosphate (ATP) pools of 3T3 cells, but not of HeLa cells. We have previously demonstrated that the effects of RA on cellular ATP pools of 3T3 cells are directly related to its inhibition of cellular growth, and now report data which provide a biochemical basis for this process. Established procedures were utilized to investigate the effects of RA on the functional compartmentalization of the nuclear ATP pool which serves as a precursor for RNA synthesis in these cells, and which is shown to be a small pool in comparison with cytoplasmic ATP pools. Expansion of total cellular ATP pools by 1 mM of exogenously supplied unlabeled adenosine is ineffective in reducing the subsequent incorporation of [3H]adenosine into RNA of 3T3 cells. Similar treatment of HeLa cells yields a modest reduction in the incorporation of [3H]adenosine into RNA. RA treatment of HeLa cells does not affect the preferential uptake of exogenous [3H] adenosine into the immediate precursor ATP pool for RNA synthesis. RA treatment of 3T3 cells markedly reduces the incorporation of [3H] adenosine into RNA, indicating a lesser degree of functional compartmentalization of the nuclear ATP pool. Similar conclusions are drawn from correlations of the specific radioactivities of total cellular [3H] ATP pools and the levels of incorporation of radioactive label into cellular RNA. In addition, pulse-chase experiments show that RA-treated 3T3 cells continue to incorporate radioactive label from pools prelabeled with [3H]adenosine despite the presence of a large excess of unlabeled adenosine in the chase medium. Control 3T3 and both control and RA-treated HeLa cells cease to incorporate label immediately upon the start of the chase, suggesting that the functional precursor ATP pool for RNA synthesis is small and readily diluted. These data suggest that RA decreases the degree of functional compartmentalization for 3T3, but not HeLa cell ATP pools, and provides a probable mechanism for expansion of nuclear ATP pools of 3T3 cells. The expanded nuclear ATP pools may provide the biochemical mechanism for the inhibition of DNA synthesis during the S phase of the 3T3 cell cycle.

Influence of animal hibernation on the development of mycoses

The development of adiaspiromycosis and trichophytosis depending upon the state of activity of red-cheeked squirrels is described. The conidia of Chrysosporium (Emmonsia) parvum var. crescens, are not transformed into adiaspores when injected into hibernating animals. During the hibernation period of four months, most of the conidia die. After awakening, the remaining viable conidia are transformed into adiaspores. During hibernation the squirrels, which had been infected with Trichophyton mentagrophytes var. granulosum, developed a symptom-free infection.

Safety of megavitamin therapy

Carbon compounds that are needed in small amounts in the diet because they are not made in the body of vertebrates are defined as vitamins. Excluded from this definition are vitamins D, K, and niacin which can be synthesized by the organism or, as in the case of vitamin K, by the host's intestinal bacteria. Lack of such vitamins can result in characteristic deficiency diseases. The therapeutic use of such compounds (megavitamin intake) is based on the spectacular effect of vitamins on deficiency diseases; however, evidence that the ingestion of large amounts of vitamins beyond the "Recommended Daily Allowances" (RDA) is beneficial is not within the basic concept of nutrition. Vitamins, like many substances, may be toxic when taken in large quantities, especially the fat-soluble vitamins, and the concept of "more is better" is a common misconception. Vitamin supplements can be suggested only in the unusual cases of patients having inadequate intake, disturbed absorption (genetic or otherwise), or increased tissue requirements. A well-balanced diet that includes a wide variety of foods from each of the four food groups is adequate for the supply of vitamins, as well as other nutrients, in healthy people. This paper will review some of the recent findings regarding vitamin toxicity and the mechanisms of toxicity.

Prevention of 3-methylcholanthrene-induced skin tumors in mice by simultaneous application of 13-cis-retinoic acid and retinyl palmitate (vitamin A palmitate)

Two retinoids (13-cis-retinoic acid and retinyl palmitate ) have been shown to exert a good preventive effect in chemically induced papillomas and carcinomas of the skin in female Swiss mice; this effect was investigated over a period of 23 weeks. The tumors were induced by repeated topical application of 3-methylcholanthrene (0.3% MCA, dissolved in acetone; 14 applications). Retinyl palmitate (RP; 6 mg in 0.1 ml acetone/mouse; 10 applications) and 13-cis-retinoic acid (RA; 3 mg in 0.1 ml acetone/mouse; 10 applications) were also administered topically for the 3rd to 9th week from the start of the experiment. This investigation gave evidence for the fact that both the retinoids did not only inhibit the development of skin papillomas but had also a marked effect on skin carcinomas.

Effect of lipophilic vitamins on the erythrocyte membrane. 31P NMR and fluorescence studies

Structural changes induced by the fat-soluble vitamins A, D3, E and K1 in natural membranes were studied by 31P NMR and fluorescence anisotropy on erythrocyte ghosts; the occurrence of cell fusion following vitamin addition was detected by optical microscopy of intact cells. Vitamins A, E and K1, which produce cell fusion, also induce the formation of configurational phases other than the bilayer and increase, at a different extent for the different vitamins, membrane fluidity. Vitamin D3, on the contrary, induces aggregation without fusion, paralleled by bilayer phase stabilization and microviscosity increase. A correlation between fusion phenomena and structural variations in the bilayer organization is therefore suggested.

Immunological role of vitamin A and its related substances in prevention of cancer

The antitumor effects of vitamin A and its related substances, vitamin E, vitamin K, beta-carotene, ubiquinone, phytol, and squalene, were examined using a syngeneic murine tumor system. Intraperitoneal administration of these substances (0.19 mumol/mouse/day) slightly suppressed the growth of Meth A fibrosarcoma cells inoculated s.c. into Balb/c mice. Administration of all test substances except beta-carotene significantly suppressed the growth of Meth A fibrosarcoma cells rechallenged in Meth A-primed mice on day 10, but did not influence the growth of Meth 1 fibrosarcoma cells (another syngeneic tumor of Balb/c origin) rechallenged in Meth A-primed mice on day 10. The growth of Meth A tumor cells was suppressed when Meth A was inoculated together with lymph node cells obtained from the Meth A-primed Balb/c mice treated with vitamin A, vitamin E, phytol, or squalene. Our findings suggest that certain constituents in green-yellow vegetables may contribute to the prevention of cancer by augmenting an immunological response against tumor cells in the early stages of carcinogenesis.

The effects of retinol (vitamin A alcohol) and various non-ionic detergents on he surfaces of schistosomula and adult Schistosoma mansoni

It was found that retinol at concentrations of 0.2-1.0 mg . ml-1 caused significant 51Cr release from schistosomula, while adult worms appeared unaffected. Retinol was shown, by spectrofluorimetry and fluorescence microscopy, to be absorbed into the membrane systems of both schistosomulum and adult worm, particularly when the parasites were incubated in retinol dissolved in non-ionic detergents (Tweens 20, 40 and 80). The retinol within the adult membrane could be induced to cause detectable 51Cr and 125I wheat germ agglutinin release if the adult was treated with retinol in combination with Tween 20. The effect of the combination of Tween 20 and retinol, was synergistic for the release of both isotopes. Their synergism was also observed when haemolysis of human erythrocytes was measured. Thus it is possible to greatly enhance the effect on the schistosome and the erythrocyte membrane of one membrane-active compound by presenting it in combination with another. This may have implications in chemotherapy when membrane active drugs are employed.

Retinoic acid delays the terminal differentiation of keratinocytes in suspension culture

The effect of retinoic acid (RA) on the terminal differentiation of guinea pig keratinocytes maintained in suspension culture was studied. Keratinocytes obtained from trypsinized guinea pig skin were suspended in medium containing 20% calf serum and 1.2% methyl cellulose. RA, which was added at the beginning of culture, delayed differentiation as judged by a decrease in the percent of cells that developed disulfide cross-linked keratin (sodium dodecyl sulfate insoluble cells) and cornified envelopes (sodium dodecyl sulfate and 2-mercaptoethanol insoluble cells). RA inhibited differentiation maximally at 5 microgram/ml on day 3 of 5 day culture; concentrations as low as .005 microgram/ml were also inhibitory. Because the disulfide cross-linking of keratin and the formation of cornified envelopes are thought to occur when the cell membrane becomes permeable, we determined whether RA inhibited these processes by stabilizing the cell membrane. Two agents (ionophore X537A and Triton X-100) which permeate cell membranes rapidly reversed the inhibitory effect of RA on cornified envelope formation. In addition, when cultured with RA, the percent of cells which became permeable to trypan blue was reduced, also suggesting that RA acts on the cell membrane. These studies show that RA can inhibit keratinocyte differentiation by stabilizing the cell membrane thereby delaying transition from a living epidermal cell to a dead cornified cell.

The influence of excess vitamin A on neural tube closure in the mouse embryo

The effect of excess vitamin A on the closure of the neural tube in mouse embryos was examined with light microscopy, transmission and scanning electronmicroscopy. The embryos were treated with the vitamin just before closure of the brain vesicles and examined during the following 24 h, a period during which under normal conditions the brain completely closes. At 18--24 h after treatment the external features of the treated specimens began to differ from those of the controls. In the treated embryos the neural walls folded laterally and became widely separated, whereas those of the controls folded dorsomedially and fused in the midline. Histologically, the first difference between treated and control embryos was noted at two hours after treatment, when large intercellular spaces appeared between the neuroepithelial cells of the treated embryos. These spaces were mainly present between the apical ends of the wedge-shaped neuroepithelial cells. This accumulation of intercellular spaces interfered with the normal morphogenetic movement of the neural walls which remained convex instead of becoming concave. This convex bending resulted in non-closure of the neural tube. In addition to the appearance of large intercellular spaces some neuroepithelial cells as well as some mesenchymal, endothelial, and surface ectoderm cells showed swelling and degeneration as a result of the vitamin A treatment. This cell degeneration probably contributes to failure of the neural tube to close due to loss of cohesion at the luminal surface and the lack of mesenchymal support needed for the elevation of the neural walls. However, the increase of intercellular spaces at the apical side of the neuroepithelium is in all probability the major cause for the failure of the neural tube to close.