SEARCH · PubMed Health
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Many cosmeseuticals and drugs are available to treat and augment therapy for the aging face. Patients frequently have misconceptions about the use of these agents, and it is important that today's cosmetic surgeon know how to maximize the benefits while minimizing side effects. The role of retinoids, antioxidants, hydroxy acids, bleaching agents, moisturizers, and sunscreens are reviewed as they relate to skin rejuvenation.
The formation of thromboxane B2 (TxB2), 12L-hydroxy-5,8,10 heptadecatrienoic acid (HHT) and 12L-hydroxy-5,8,10,14 eicosatrienoic acid (HETE) was determined in the platelets of normal human males and of patients with disorders in which an abnormal platelet aggregation occurs. Platelets were labelled with [1-14C] arachidonic acid. After Aggregation and extraction the metabolites wee separated by TLC and determined. In the platelets of normal males, TxB2 values were in the range 4.4-12.4%, expressed as a percentage of total radioactivity. Curves were constructed for the following ratios: TxB2 :HHT, TxB2 :HETE and (TxB2 + HHT) :HETE. These ratios were fairly contant. A comparison was made with the ratios obtained in the platelets of a small number of patients with either an enhanced or a diminished aggregation.
Peroxisome proliferation has been induced with 2-methyl-2-(p-[1,2,3,4-tetrahydro-1-naphthyl]-phenoxy)-propionic acid (Su-13437). DNA, protein, cytochrome oxidase, glucose-6-phosphatase, and acid phosphatase concentrations remain almost constant. Peroxisomal enzyme activities change to approximately 165%, 50%, 30%, and 0% of the controls for catalase, urate oxidase, L-alpha-hydroxy acid oxidase, and D-amino acid oxidase, respectively. For catalase the change results from a decrease in particle-bound activity and a fivefold increase in soluble activity. The average diameter of peroxisome sections is 0.58 +/- 0.15 mum in controls and 0.73 +/- 0.25 mum after treatment. Therefore, the measured peroxisomal enzymes are highly diluted in proliferated particles. After tissue fractionation, approximately one-half of the normal peroxisomes and all proliferated peroxisomes show matric extraction with ghost formation, but no change in size. In homogenates submitted to mechanical stress, proliferated peroxisomes do not reveal increased fragility; unexpectedly, Su-13437 stabilizes lysosomes. Our results suggest that matrix extraction and increased soluble enzyme activities result from transmembrane passage of peroxisomal proteins. The changes in concentration of peroxisomal oxidases and soluble catalase after Su-13437 allow the calculation of their half-lives. These are the same as those found for total catalase, in normal and treated rats, after allyl isopropyl acetamide: about 1.3 days, a result compatible with peroxisome degradation by autophagy. A sequential increase in liver RNA concentration, [14C]leucine incorporation into DOC-soluble proteins and into immunoprecipitable catalase, and an increase in liver size and peroxisomal volume per gram liver, characterize the trophic effect of the drug used. In males, Su-13437 is more active than CPIB, another peroxisome proliferation-inducing drug; in females, only Su-13437 is active.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Niemann-Pick disease, type C, was diagnosed in a 3-month-old boy with hepatosplenomegaly, mild signs of cholestasis, hepatic inflammation and extramedullary erythropoiesis, together with chronic airway disease. He developed muscular hypotonia, psychomotor retardation, rickets, and signs of peripheral neuropathy. The patient was found to excrete abnormal amounts of unusual bile acids in urine at 3 and 5 months of age. These acids were shown to have a 3beta-hydroxy-Delta(5) structure and to carry an oxo or hydroxy group at C-7. They were sulfated at C-3 and nonamidated or conjugated with glycine or taurine at C-24. Part of the 7-hydroxy acids, presumably the 7beta-hydroxylated one, was also conjugated with N-acetylhexosamine, probably N-acetylglucosamine, at the 7-hydroxy group. Possible metabolic pathways for the formation of the 7-oxo and 7beta-hydroxycholenoic acids are discussed. Based on previous data concerning the effects of 3beta-hydroxy-Delta(5) bile acids on bile acid transport, it is suggested that the formation of such bile acids is responsible for the cholestasis in this patient.
This article describes the production of stereoselective antibodies using both classical immunological and modern molecular biological techniques. Stereoselective antibodies against alpha-hydroxy acids were raised in rabbits and mice and compared with previously produced anti-alpha-amino acid antibodies. It was found that both types of antibodies combine stereoselectivity with class-specificity. Sequence analyses revealed that antibodies with opposing stereoselectivities can be formed during the affinity maturation process from a common progenitor or independently using nonhomologous binding sites. For the first time, phage display was employed to obtain stereoselective antibody fragments. The versatility of stereoselective antibodies as chiral selectors was demonstrated by applying them in several immunosensors and in chiral chromatography. A simple, membrane-based optical sensor allowed detection of enantiomeric impurities at the 1/2,000 level (99.9% ee). Silica-based antibody chiral stationary phases could be used for enantiomer separation of aliphatic amino acids in standard-sized columns, while miniaturized columns allowed interfacing with an MS-detector.
Biotransformation of oleic acid with Pseudomonas sp. 42A2 has been found to produce(E)-10-hydroxy-8-octadecenoic acid (2a), (E)-10-hydroperoxy-8-octadecenoic acid (3a), and (E)-7,10-dihydroxy-8-octadecenoic acid (4a). Structures of the metabolites were fully characterized by infrared and 1H and 13C NMR spectra of the acids, by fast atom bombardment (FAB) and electron impact (EI) and chemical ionization (CI) mass spectrometry of the corresponding methyl esters. This is the first time that the two former compounds of trans stereochemistry have been described to have originated from a Pseudomonas sp. cell culture. Time course of products accumulation showed that biotransformation started with bacterial growth, the amount of products 2a (5.58 g/l) and 4a (2.63 g/l) being optimum after 24 h of incubation while hydroperoxide 3a (1.15 g/l) reached its maximum after 16 h of the biotransformation process. Experiments conducted to ascertain whether the conversion enzyme(s) was cell-bound or extracellular, showed that the enzyme(s) is cell bound, located in the periplasmic space and has lipoxygenase activity.
Evaluation of the aging face reveals many changes such as lentigines, coarseness, senile purpura, and fine lines that can be blamed primarily on photoaging. There are many topical preparations that are now being used or are under investigation for facial rejuvenation. These include retinold creams, alpha-hydroxy acids, Ethocyn (Chantal Skin Care Corp, Los Angeles, CA), topical vitamins, and topical hormonal treatments. There has been substantial media attention devoted to these "antiaging" cures but there is a lack of scientific evidence to support some of these claims. After review of these agents, a practical approach to the patient requesting younger-looking skin is presented.
Sales of soft drinks has been increasing by 56% over the last 10 years and are estimated to keep rising at about 2-3% a year. Further, the reported incidence of tooth erosion has been increasingly documented. Whilst these factors could well be linked, many individuals with erosive diets are not presenting with erosion. This would suggest the effects of many variables, hence the aim of these investigations. Methodologies included preparing enamel and dentine samples from unerupted human third molars. Groups of five specimens were placed in citric acid over a temperature range of 5-60 degrees C for 10-min exposures; placed in citric, lactic, malic or phosphoric acid (0.05, 0.1, 0.5, and 1% (w/v)) for 10-min exposures; and placed in the same three organic hydroxy acids at 0.3% (w/v) or phosphoric acid at 0.1% (w/v) for 3 x 10-min exposures. Tissue loss was determined by profilometry. Results showed that increasing temperature, concentration and exposure time increased the erosion of dentine and enamel. This study has shown that under highly controlled conditions, erosion of dentine and enamel by dietary acids can be greatly influenced in vitro by temperature, concentration, type of acid and exposure time. These factors could be employed in order to reduce the erosivity of soft acidic drinks.
Two NADPH-dependent oxidoreductases catalyzing the enantioselective reduction of 3-oxo esters to (S)- and (R)-3-hydroxy acid esters, [hereafter called (S)- and (R)-enzymes] have been purified 121- and 332-fold, respectively, from cell extracts of Saccharomyces cerevisiae by means of streptomycin sulfate treatment, Sephadex G-25 filtration, DEAE-Sepharose CL-6B chromatography, Sephadex G-150 filtration, Sepharose 6B filtration and hydroxyapatite chromatography. The relative molecular mass Mr, of the (S)-enzyme was estimated to be 48,000-50,000 on Sephadex G-150 column chromatography and 48,000 on sodium dodecyl sulfate/polyacrylamide gel electrophoresis. The enzyme was most active at pH 6.9 and reduced 3-oxo esters, 4-oxo and 5-oxo acids and esters enantioselectively to (S)- hydroxy compounds in the presence of NADPH. The Km values for ethyl 3-oxobutyrate, ethyl 3-oxohexanoate, 4-oxopentanoic and 5-oxohexanoic acid were determined as 0.9 mM, 5.3 mM, 17.1 mM and 13.1 mM, respectively. The Mr of the (R)-enzyme, estimated by means of column chromatography on Sepharose 6B, was 800,000. Under dissociating conditions of SDS/polyacrylamide gel electrophoresis the enzyme resolved into subunits of Mr 200,000 and 210,000, respectively. The enzyme is optimally active at pH 6.1, catalyzing specifically the reduction of 3-oxo esters to (R)-hydroxy esters, using NADPH for coenzyme. Km values for ethyl 3-oxobutyrate and ethyl 3-oxohexanoate were determined as 17.0 mM and 2.0 mM, respectively. Investigations with purified fatty acid synthase of baker's yeast revealed that the (R)-enzyme was identical with a subunit of this multifunctional complex; intact fatty acid synthase (Mr 2.4 X 10(6)) showed no activity in catalyzing the reduction of 3-oxo esters.
Aldol products (3-hydroxy acids) with an allyl-protected hydroxy group were converted to amino alcohols by Curtius rearrangement. Combination of the carboxylic acid with the amino alcohols gave the amides 10. Ring-closing metathesis led to the 12-membered lactams 12 as mixtures of E/Z-isomers. The scheme was also transferred to the solid-phase. In this case the macrolactams are formed via cyclorelease. For a pair of E/Z-isomers the solution conformation was determined by ROESY spectroscopy.
When Pseudomonas putida ATCC 39167 and plant-deleterious Pseudomonas fluorescens A225 were grown in an iron-deficient culture medium, they each produced two different novel yellow-green fluorescent pseudobactins: P39167-I, II and PA225-I, II. Pseudobactin P39167-I has a molecular formula of C46H65O23N13 and is monoanionic at neutral pH. P39167-II has the molecular formula of C46H63O22N13 and no charge at neutral pH. Pseudobactin PA225-I has a molecular formula of C46H65O24N13 and is monoanionic at neutral pH whereas pseudobactin PA225-II has the molecular formula of C46H63O23N13 and no charge at neutral pH. All four of the pseudobactins contain a dihydroxyquinoline-based chromophore. The amino acid sequence for the octapeptide in case of pseudobactins from P. putida ATCC 39167 is Chr-Ser(1)-Ala(1)-AcOHOrn-Gly-Ala(2)-OHAsp-Ser(2)-Thr. In case of pseudobactins from P. fluorescens A225, the octapeptide has the sequence Chr-Ser(1)-Ala-AcOHOrn-Gly-Ser(2)-OHAsp-Ser(3)-Thr. For all four pseudobactins (P39167-I, II and PA225-I, II), the serine(1) residue of the octapeptide is attached to the carboxylic acid group on the C-11 of the fluorescent quinoline via an amide bond. Additionally, for pseudobactin P39167-II and PA225-II, the hydroxyl group of the serine(1) residue is also attached to the carboxyl group of threonine residue at the carboxy terminus of the peptide via an ester bond, resulting in a cyclic depsipeptide in contrast to the linear peptide chain of P39167-I and PA225-I. For all four pseudobactins, a malamide group is attached to the C-3 of the quinoline derived chromophore. The three bidentate iron(III) chelating groups in all four pseudobactins consist of a 1,2-dihydroxy aromatic group of the fluorescent chromophore, a hydroxy acid group of beta-hydroxy aspartic acid, and a hydroxamate group from the acylated Ndelta-hydroxyornithine. The amino acid constituents of the pseudobactins P39167 I, II are the same as those in pseudobactin A214, whereas those in A225 I, II are the same as in 7SR1, but in both cases the sequences are different. The uptake results indicate a single outer membrane receptor protein for ferric-pseudobactins in both organisms. The receptor proteins in the two species are similar but not identical.
Cunninghamella elegans metabolized 1- and 2-methylnaphthalene primarily at the methyl group to form 1- and 2-hydroxymethylnaphthalene, respectively. Other compounds isolated and identified were 1- and 2-naphthoic acids, 5-hydroxy-1-naphthoic acid, 5-hydroxy-2-naphthoic acid, 6-hydroxy-2-naphthoic acid, and phenolic derivatives of 1- and 2-methylnaphthalene. The metabolites were isolated by thin-layer and reverse-phase high-pressure liquid chromatography and characterized by the application of UV-visible absorption, 1H nuclear magnetic resonance, and mass spectral techniques. Experiments with [8-14C]2-methylnaphthalene indicated that over a 72-h period, 9.8% of 2-methylnaphthalene was oxidized to metabolic products. The ratio of organic-soluble in water-soluble metabolites at 2 h was 92:8, and at 72 h it was 41:59. Enzymatic treatment of the 48-h aqueous phase with either beta-glucuronidase or arylsulfatase released 60% of the metabolites of 2-methylnaphthalene that were extractable with ethyl acetate. In both cases, the major conjugates released were 5-hydroxy-2-naphthoic acid and 6-hydroxy-2-naphthoic acid. The ratio of the water-soluble glucuronide conjugates to sulfate conjugates was 1:1. Incubation of C. elegans with 2-methylnaphthalene under an 18O2 atmosphere and subsequent mass spectral analysis of 2-hydroxymethylnaphthalene indicated that hydroxylation of the methyl group is catalyzed by a monooxygenase.
OBJECTIVE: To evaluate the efficacy and tolerability of 2 widely used topical alpha-hydroxy acids at low concentrations, 8% glycolic acid and 8% lactic (L-isoform) acid creams, in the treatment of photodamaged skin. DESIGN: A single-center, 22-week, double-blind, vehicle-controlled, randomized clinical trial assessed the overall severity of photodamage on the faces and forearms of volunteers, based on 7 individual clinical components of cutaneous photodamage. SETTING: The study was performed in an outpatient clinical research unit at the Massachusetts General Hospital, Boston. PATIENTS: Seventy-four women, aged 40 to 70 years, with moderately severe photodamaged facial skin were enrolled in the study. One subject withdrew from the study early because of skin irritation, and 6 subjects withdrew from the study for personal reasons. INTERVENTIONS: Glycolic acid, L-lactic acid, or vehicle creams were applied twice daily to the face and outer aspect of the forearms. MAIN OUTCOME MEASURES: Improvement in alpha-hydroxy acid-treated photodamaged skin as determined by patient self-assessments and physician evaluations of efficacy and irritancy. RESULTS: The percentage of patients using either 8% glycolic acid or 8% L-lactic acid creams on the face achieving at least 1 grade of improvement (using a scale from 0 through 9) in overall severity of photodamage was significantly greater than with the vehicle cream (76% glycolic acid, 71% lactic acid, and 40% vehicle; P < .05). On the forearms, after 22 weeks, treatment with glycolic acid cream was superior to the vehicle in improving the overall severity of photodamage and sallowness (P < .05). L-Lactic acid cream was significantly superior to the vehicle in reducing the overall severity of photodamage (P < .05), mottled hyperpigmentation (P < .05), sallowness (P < .05), and roughness on the forearms (P < .05) at week 22. CONCLUSIONS: Topical 8% glycolic acid and 8% L-lactic acid creams are modestly useful in ameliorating some of the signs of chronic cutaneous photodamage. These agents are well tolerated and available without prescription.
A very unusual pattern of organic acid excretion was established in the urine of two premature newborns with severe respiratory distress and cerebral haemorrhages. By combined gas chromatography/mass spectrometry the following acids were identified: lactic acid, alpha-hydroxy-butyric acid, beta-hydroxy-butyric acid, alpha-hydroxy-isovaleric acid, and p-hydroxy-phenyllactic acid. Calculation of the concentration revealed an excessive excretion of lactic acid and also very high excretion of the other acids. A postmortem blood sample from one of the patients revealed a comparable pattern. The abnormal urinary organic acid excretion pattern was most probably caused by severe tissue hypoxia.
We used gas chromatography--tandem mass spectrometry to analyze microbial components in 85 samples of airborne dust from schools in Jordan, Sweden, and Poland. To collect the samples, we allowed dust to settle on plexiglass plates hanging in the breathing zone in school buildings during both summer and winter. In each of the three countries, we conducted such sampling in two schools: one in an urban environment and the other in rural surroundings. The microbial marker profiles differed significantly between the schools and seasons. For example, samples from Jordan contained remarkably low levels of ergosterol (marker of fungal biomass) and high levels of 3-hydroxy acids (markers of lipopolysaccharide) of 10, 12, and 14 carbon chain lengths relative to such acids of 16 and 18 carbons in comparison with samples from Sweden and Poland. This dissimilarity in 3-hydroxy fatty acid distribution indicates significant differences in the populations of Gram-negative bacteria. We also noted that muramic acid (marker of bacterial biomass) exhibited the smallest variation between schools and seasons. In summary, our results demonstrate that exposure to microorganisms in indoor air in school buildings may differ markedly between countries, between seasons, and between urban and rural environments.