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PubMed2004

Morphological, chemical and functional analysis of catuaba preparations.

Fourteen commercial samples of the popular Brazilian aphrodisiac Catuaba specified as bark drugs of Anemopaegma, Erythroxylum and Trichilia species were examined for identity and purity. Only a minority of the examined Catuaba samples contained the crude drugs claimed on the labels. More than half of the products were adulterated with different crude drugs. The majority of the samples contained a bark originating from Trichilia catigua. The TLC fingerprints confirmed the heterogeneity, in 50% of the samples tropane alkaloids of various concentrations were detected. TLC and HPLC methods for separation and identification of the tropane alkaloids were developed and their analytical data (RF values, retention times, ESI-MS) given. The structure elucidation of the two main alkaloids, catuabine D and its hydroxymethyl derivative, is presented. The 1H- and 13C-NMR assignments of these alkaloids are discussed with regard to literature data. Neither aqueous nor methanolic extracts of the Trichilia catigua reference material nor alkaloid-enriched fractions of commercial samples showed any effect on the rabbit corpus cavernosum in an in vitro test.

Animals↗
PubMedDate not supplied

[Acid-base regulation in premature babies and infants fed on human milk and cow milk nutrients].

Babies receiving formulas based on cow's milk show a higher renal net acid excretion than babies receiving human milk. Nutrition producing a high renal net acid excretion may cause clinical problems. Formula based on cow's milk should be modified in order to decrease the acid load. Renal net acid excretion may be estimated from the analytical data of a diet. Possibilities to decrease renal acid excretion in infant feeding are discussed.

Acid-Base Equilibrium↗
PubMed2002

A gene encoding a protein modified by the phytohormone indoleacetic acid.

We show that the expression of an indole-3-acetic acid (IAA)-modified protein from bean seed, IAP1, is correlated to the developmental period of rapid growth during seed development. Moreover, this protein undergoes rapid degradation during germination. The gene for IAP1, the most abundant protein covalently modified by IAA (iap1, GenBank accession no. ) was isolated and cloned from bush bean (Phaseolus vulgaris) seeds. The 957-bp sequence encodes a 35-kDa polypeptide. IAA-modified proteins represent a distinct class of conjugated phytohormones and appear in bean to be the major form of auxin in seeds. IAA proteins also are found at other stages of development in bean plants. Our immunological and analytical data suggest that auxin modification of a small class of proteins may be a feature common to many plants.

Amino Acid Sequence↗
PubMed1972

Binding proteins for an ecdysone metabolite in the crustacean hepatopancreas.

When crustacean hepatopancreas is incubated in the presence of alpha-(3)H]ecdysone of high specific activity and is then homogenized and centrifuged, a peak of protein-radioactivity is recovered after gel filtration of the 105,000 x g supernatant. Analysis of this peak by sucrose gradient centrifugation revealed the presence of two complexes of protein and labeled material ( approximately 11.5 S and 6.35 S). The same results were obtained in vivo. On standing at low ionic strength, the lighter component disappeared, suggesting that the heavier component is an aggregate of the lighter one. Chemical analysis of radioactive material in the complex revealed that it is not alpha- or beta-ecdysone nor any previously described metabolite of the ecdysones. This new metabolite of alpha-ecdysone is found mainly in the incubated hepatopancreas. Partial structures consistent with the analytical data are inferred for this metabolite. It is suggested that the metabolite may be active in the action of molting hormone.

Animals↗
PubMed1981

Primary structure of corticotropin-releasing factor from ovine hypothalamus.

Sequence analysis was performed of an ovine hypothalamic 41-residue polypeptide that had been postulated to be a putative corticotropin-releasing factor (CRF) because of its high intrinsic corticotropin releasing activity. The NH2-terminal 39 residues of CRF were determined by Edman degradation of 0.6-3.5 nmol of peptide in a Wittmann-Liebold modified Beckman 890C spinning cup sequencer with reverse-phase high-pressure liquid chromatography for the identification of amino acid phenylthiohydantoins (direct micro-sequence analysis). Evidence for residue 40 (isoleucine) was provided by direct micro-sequence analysis of 2.0 nmol of acetylated CRF selectively cleaved at its arginine residues by trypsin prior to analysis. The thermolytic COOH-terminal fragment isoleucyl-alanineamide was characterized as its dansyl derivative. Based on the analytical data, the following primary structure is proposed for ovine hypothalamic CRF: H-Ser-Gln-Glu-Pro-Pro-Ile-Ser-Leu-Asp-Leu-Thr-Phe-His-Leu-Leu-Arg-Glu-Val-Leu-Glu-Met-Thr-Lys-Ala-Asp-Gln-Leu-Ala-Gln-Gln-Ala-His-Ser-Asn-Arg-Lys-Leu-Leu-Asp -Ile-Ala-NH2. In agreement with this proposal, the synthetic replicate of CRF is highly potent in stimulating secretion of both corticotropin and beta-endorphin-like immunoactivities.

Adrenocorticotropic Hormone↗
PubMed1995

The pH-sensitive actin-binding protein hisactophilin of Dictyostelium exists in two isoforms which both are myristoylated and distributed between plasma membrane and cytoplasm.

The histidine-rich protein hisactophilin is known to be associated with the inner surface of the plasma membrane and to be present as a soluble protein in the cytoplasm of Dictyostelium discoideum cells. Mass spectrometry of hisactophilin from the cytosol or extracted from a membrane fraction showed that none of the hisactophilin purified from D. discoideum cells had the mass predicted from the known cDNA-derived amino acid sequence of the protein. Electrospray mass spectrometry and liquid secondary ion mass spectrometry of tryptic fragments separated by reversed-phase high performance liquid chromatography (HPLC) identified the most hydrophobic peptide as a myristoylated fragment from the N terminus of hisactophilin. Taken together the analytical data, it is concluded that all hisactophilin in D. discoideum cells is N terminally modified by myristoylation. By reversed-phase HPLC, two isoforms of hisactophilin, HsI and HsII, were recovered from the cytosolic as well as the membrane fraction of D. discoideum cells. Whereas the masses of HsI fragments produced by trypsin fit into the previously published sequence of hisactophilin (myristoylation considered), HsII is another protein distinguished from HsI by several amino acid exchanges. HsI and HsII can form homo- and heterodimers by disulfide bridges. Hisactophilin is phosphorylated in vivo. Both isoforms proved to be substrates of membrane-associated threonine/serine kinase from D. discoideum, which may regulate the interaction of hisactophilin with the plasma membrane.

Actins↗
PubMed1999

Analysis of the pre-S2 N- and O-linked glycans of the M surface protein from human hepatitis B virus.

The surface antigen of hepatitis B virus comprises a nested set of small (S), middle (M), and large (L) proteins, all of which are partially glycosylated in their S domains. The pre-S2 domain, present only in M and L proteins, is further N-glycosylated at Asn-4 exclusively in the M protein. Since the pre-S2 N-glycan appears to play a crucial role in the secretion of viral particles, the M protein may be considered as a potential target for antiviral therapy. For characterization of the pre-S2 glycosylation, pre-S2 (glyco)peptides were released from native, patient-derived hepatitis B virus subviral particles by tryptic digestion, separated from remaining particles, purified by reversed-phase high performance liquid chromatography, and identified by amino acid and N-terminal sequence analysis as well as matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Pre-S2 N-glycans were characterized by anion exchange chromatography, methylation analysis, and on target sequential exoglycosidase digestions in combination with MALDI-TOF-MS, demonstrating the presence of partially sialylated diantennary complex-type oligosaccharides. In addition, the pre-S2 domain of M protein, but not that of L protein, was found to be partially O-glycosylated by a Gal(beta1-3)GalNAcalpha-, Neu5Ac(alpha2-3)Gal(beta1-3)GalNAcalpha-, or GalNAcalpha-residue. The respective O-glycosylation site was assigned to Thr-37 by digestion with carboxypeptidases in combination with MALDI-TOF-MS and by quadrupole time-of-flight electrospray mass spectrometry. Analytical data further revealed that about 90% of M protein is N-terminally acetylated.

Amino Acid Sequence↗
PubMed2004

Backpropagation and regression: comparative utility for neuropsychologists.

The aim of this research was to compare the data analytic applicability of a backpropagated neural network with that of regression analysis. Thirty individuals between the ages of 64 and 86 (Mean age = 73.6; Mean years education = 15.4; % women = 50) participated in a study designed to validate a new test of spatial ability administered in virtual reality. As part of this project a standard neuropsychological battery was administered. Results from the multiple regression model R(2) = .21, p < .28; Standard Error = 18.01) were compared with those of a backpropagated ANN (R(2) = .39, p < .02; Standard Error = 13.07). This 18% increase in prediction of a common neuropsychological problem demonstrated that an ANN has the potential to outperform a regression.

Aged↗
PubMed2001

A critical assessment of some biomarker approaches linked with dietary intake.

In this review many examples are given of the complexities involved in using some biomarkers in relation to assessing the effects of dietary exposure, when there is frequently a need to determine changes following long-term low level exposure to dietary components. These range from understanding why the biomarker might be valuable and how best it can be measured, to the pitfalls which can occur in the interpretation of data. Analytical technique is considered in relation to folate and selenium, and flavonoid and carotenoid species are used to illustrate how the metabolism of a compound may alter the validity or adequacy of a marker. Vitamin A is discussed in relation to the difficulties which can arise when there are several biomarkers that may be available to assess exposure to one nutrient. Vitamin B12 is discussed in relation to the dietary choices made by individuals. Possible interactions and the role of measuring total antioxidant capacity is considered in some detail. In contrast to most nutrients, there is a marked lack of biomarkers of either exposure or effect for most non-nutrients. The role of biological effect monitoring is considered for dietary contaminants, fumonisins and polyhalogenated aromatic hydrocarbons. Aflatoxins are discussed to exemplify food contaminants for which the biomarker approach has been extensively studied. Finally some compounds which are deliberately added to foods and some which appear as processing contaminants are each considered briefly in relation to the requirement for a biomarker of exposure to be developed.

Aflatoxins↗
PubMed2001

A critical evaluation of the application of biomarkers in epidemiological studies on diet and health.

One of the problems which may beset epidemiological studies is the difficulty of accurately measuring the dietary intakes of participants. Biomarkers of diet promise to provide a more accurate measure of dietary intake and a more objective one in that they are not reliant on the subject's memory. This review considers some issues of importance in epidemiology when information is obtained from biomarkers. The approach taken is to use examples both of normal dietary constituents and of contaminants in relation to a range of diet and health questions to illustrate these points. A brief overview of the role of sample collection, processing and storage is given including some generic recommendations for maximising the reliability of subsequent analytical data. Using the examples of phytoestrogens and iodine the question of whether biomarkers can accurately reflect the intake of the dietary constituents of interest at the population level or at the individual level is considered. The relationship of the biomarker to the natural history of the disease is exemplified using the role of folate in neural tube defects. Finally, intakes of vitamin D and heterocyclic amines are used to illustrate the integration of biomarkers into epidemiological studies of prostate and colorectal cancer, respectively. It is concluded that biomarkers may provide a more accurate and objective measure of diet than estimates of current or usual intake but that this approach also has limitations. A combination of methods will probably prove to be most valuable and this approach is being taken in current large prospective studies.

Biomarkers↗
PubMed2005

The absorption, metabolism and excretion of flavan-3-ols and procyanidins following the ingestion of a grape seed extract by rats.

Rats were fed a grape seed extract (GSE) containing (+)-catechin, (-)-epicatechin and dimers, trimers, tetramers and polymeric procyanidins. Liver, kidney, brain and gastrointestinal (GI) tract together with plasma, urine and faeces were collected over a 24 h period and their flavan-3-ol content was analysed by HPLC with tandem mass spectrometry and diode array detection. Small amounts of the GSE flavan-3-ols moved out of the stomach and into the duodenum/jejunum, and to a greater extent the ileum 1 h after ingestion, and into the caecum after 2 h with relatively small amounts being detected in the colon after 3 h. The GI tract contained the parent GSE flavan-3-ols and procyanidins with only trace amounts of metabolites and there were no indications that proanthocyanidins were depolymerised in the GI tract releasing monomeric flavan-3-ols. Plasma contained exclusively catechin glucuronides and methylated glucuronide metabolites which were also detected in the liver and kidneys. These metabolites were also present in urine together with sulphated metabolites and low amounts of the procyanidin dimers B1, B2, B3 and B4 as well as the trimer C2 and an unknown GSE trimer. The amounts of (+)-catechin and (-)-epicatechin metabolites excreted in urine relative to the quantity of the monomers ingested were 27 and 36 %, respectively, after 24 h. This is similar to the levels of urinary excretion reported to occur by other investigators after feeding (-)-epicatechin to rats and provides further, albeit indirect, evidence that the procyanidin oligomers in the GSE were not depolymerised to monomers to any extent after ingestion. No convincing analytical data were obtained for the presence of flavan-3-ol metabolites in the brain.

Absorption↗
PubMed2001

Food composition issues--implications for the development of food-based dietary guidelines.

Sound food composition databases that are both comprehensive and representative of available foods are an essential basic tool to develop Food Based Dietary Guidelines (FBDG). The main drawbacks of current food composition databases available in the European Union are: partial coverage of foods and nutrients, variability of analytical data, lack of accuracy in the description of food items, need for harmonisation of the expression of nutrients. An inappropriate use of these databases could lead to gross errors in the assessment of the nutrient intake levels, in the identification of the major sources of a nutrient, in the comparison of data between countries and in the analysis of time trends. Inadequacy of food composition data is, in part, responsible for the failure to understand some relationships between nutrient intakes and health or disease and for difficulties in establishing quantitative dietary guidelines in terms of nutrients. Recommendations are made for the compilation of future food composition databases and tools are proposed to enhance the quality of existing data. A careful study of the food composition databases is always necessary before nutrition recommendations are given and before trends in nutrient intakes are interpreted.

Data Interpretation, Statistical↗
PubMed1987

Family factors related to the persistence of psychopathology in childhood and adolescence.

DATA collected in a large prospective longitudinal study of an epidemiological sample of children were employed to identify family risk factors for future psychopathology. Three data analytic models were used to distinguish between variables with effects on the subsequent onset of disorders, those in which increase in risk factor was accompanied by increase in disorder, and those specifically related to the duration of disorders present in the earlier assessment. Power assertive punishment techniques were most consistently related to future problems of the child, and children in unstable families who exhibited behavior or affective disorders in early childhood were more likely to have continuing problems 8 years later than were children in stable families. The relevance of these findings for primary, secondary, and tertiary prevention efforts is discussed.

Adolescent↗
PubMed1987

A process model for the development of schizophrenia.

Less than two decades ago scientists interested in the etiology of schizophrenia were still vigorously debating the nature-nurture controversy, with many adhering to the view that the illness grew either out of a constitutional deficit or a pathological family environment. Today, virtually all researchers adopt interactional models that include both constitutional and environmental factors. Interactional models are most often expressed in diathesis-stress terms: Development of schizophrenia requires both a biological vulnerability (diathesis) and stressful life circumstances that facilitate expression of the illness. Modern debate within the field now primarily focuses on understanding the characteristics of the biological diathesis, the stressful environment, and their interaction. Scientists using diathesis-stress theories have employed several research strategies (Rosenthal 1970): (1) consanguinity studies exploring the distribution of illness among the relatives of schizophrenics, (2) twin studies comparing the concordance of schizophrenic illness in monozygotic and dizygotic twin pairs reared together or apart, (3) retrospective studies examining the premorbid behavior and development of schizophrenic parents, and (4) prospective studies of children at high risk for schizophrenia. The population most frequently followed in prospective high-risk studies has been offspring of schizophrenics. Biological offspring of schizophrenics who are reared by their parents are at extremely high risk for becoming schizophrenic themselves, approximately ten times greater risk than the general population. The present paper will make use of the Israeli High-Risk Study to test a diathesis-stress model for the transmission of schizophrenia. The goodness of fit of this model to the data will be explored using a simple decision tree data analytic approach.

Child↗
PubMed2004

The Nordic Reference Interval Project 2000: recommended reference intervals for 25 common biochemical properties.

Each of 102 Nordic routine clinical biochemistry laboratories collected blood samples from at least 25 healthy reference individuals evenly distributed for gender and age, and analysed 25 of the most commonly requested serum/plasma components from each reference individual. A reference material (control) consisting of a fresh frozen liquid pool of serum with values traceable to reference methods (used as the project "calibrator" for non-enzymes to correct reference values) was analysed together with other serum pool controls in the same series as the project samples. Analytical data, method data and data describing the reference individuals were submitted to a central database for evaluation and calculation of reference intervals intended for common use in the Nordic countries. In parallel to the main project, measurements of commonly requested haematology properties on EDTA samples were also carried out, mainly by laboratories in Finland and Sweden. Aliquots from reference samples were submitted to storage in a central bio-bank for future establishment of reference intervals for other properties. The 25 components were, in alphabetical order: alanine transaminase, albumin, alkaline phosphatase, amylase, amylase pancreatic, aspartate transaminase, bilirubins, calcium, carbamide, cholesterol, creatine kinase, creatininium, gamma-glutamyltransferase, glucose, HDL-cholesterol, iron, iron binding capacity, lactate dehydrogenase, magnesium, phosphate, potassium, protein, sodium, triglyceride and urate.

Biomarkers↗
PubMed2000

Flow injection determinations of artificial sweeteners: a review.

A review is presented to show the advantages involved in the use of Flow Injection Analysis (FIA) for the determination of artificial sweeteners. The FI methods proposed for the determination of artificial sweeteners are described and compared on the basis of the detection technique used. Analytical data of interest and interferences are discussed for each sweetener.

Aspartame↗
PubMed2000

Evaluation of mycotoxin-contaminated cereals for their use in animal feeds in Hungary.

In the period between December 5, 1991 and September 17, 1998, 760 maize, 367 wheat, 119 soybean, 222 barley, 85 bran, 32 triticale, 60 oat, 14 rye and 22 sunflower samples were investigated for the presence and concentration of seven fusariotoxins (T-2 toxin, zearalenone, deoxynivalenol, nivalenol, diacetoxyscirpenol, HT-2 toxin, fusarenone-X) and OTA. The comparison of analytical data with those of the relevant literature revealed that although the incidence rate and/or concentration of Fusarium mycotoxins and OTA in Hungarian-grown cereals is occasionally considerable, the position of the country is not worse that the average of countries. Our findings indicate that soybean tends to be good substrate for trichothecene-producing fungi and the rate of contamination is regarded as substantial. The commodities were assorted into one of three quality categories. The proportion of objectionable samples was only 3.0, 2.2, 2.3 and 1.7% in maize, wheat, barley and soybean samples, respectively. However, this low rate of objection might still be a source of great economic loss. The proportion of objectionable samples was much higher in the case of bran, oat and triticale (7.1, 6.7, and 6.3%, respectively). The results of the present investigation indicate a need for regular screening for mycotoxins of importance and individual appraisal of each commodity from the point of their use in animal feeds.

Animal Feed↗