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At least 883 records · Page 49Linked to original sources
PubMed1957

Synthesis of sulfomucopolysaccharides in thyroidectomized rats.

The thyroid glands of rats were made non-functional by a single dose of iodine-131 on the 1st day after birth or by surgical removal on the 28th day. The incorporation of sulfate-sulfur into the sulfomucopolysaccharides of skeletons and pelts was found to be significantly depressed by thyroidectomy. Daily supplements of 5 or 10 gamma of L-thyroxine, started on the 28th day, increased the uptake of sulfur-35, although it did not reach normal in the 2 weeks of treatment. Autoradiograms of sections of tibiae and pelts confirmed the analytical data. The findings suggest that the synthesis of sulfomucopolysaccharides is depressed in thyroidectomized rats.

Animals↗
PubMed1962

Isolation and properties of a surface antigen of Staphylococcus aureus.

A technique is described for the isolation and purification of an antigen released into the culture medium by Staphylococcus aureus strain Smith. The antigen was found to be homogeneous when examined by free electrophoresis and analytic ultracentrifugation. Immunologic homogeneity was established by immunoelectrophoresis and quantitative precipitin tests using high titer antiserum prepared against the homologous organism. Chemical analysis showed that the antigen contained 70 per cent carbohydrate, of which approximately 30 to 35 per cent was believed to be glucosamine. The analytic data suggested that another amino sugar, probably carboxylated, was also present, but extreme lability of this compound to mild hydrolytic procedures has thus far precluded further identification. The remainder of the antigen was composed of alanine, glutamic acid, aspartic acid, lysine, glycine, serine, and threonine. No muramic acid was found. The chemical and physical data indicate that the antigen described herein is a previously unrecognized component of Staphylococcus aureus. The purified compound was capable of absorbing agglutinating antibody from antiserum prepared against S. aureus Smith, indicating that it was a surface component of this encapsulated staphylococcus. It is proposed that the antigen be known as the Smith surface antigen (SSA). The injection of SSA into rabbits did not produce precipitating antibodies. However, SSA did precipitate at low concentrations (0.5 microg/ml) with antiserum prepared against S. aureus Smith and one other strain of S. aureus tested. Antiserum against two other aureus strains reacted only with high concentrations of SSA. SSA did not react with S. albus antiserum or with normal sera from several animal species. Experiments are in progress to define further the distribution of SSA. Intradermal injection of small quantities of SSA into rabbits immunized with S. aureus Smith evoked a reaction of cutaneous hypersensitivity, which was maximal in 8 to 12 hours. SSA appeared to be the substance responsible for the ability of S. aureus Smith to resist engulfment by phagocytes, since absorption of Smith antiserum with SSA effectively removed opsonizing antibodies. SSA induced protection in mice against experimental staphylococcal disease. The subcutaneous injection of 0.1 microg resulted in protection against a subsequent intraperitoneal challenge with 50 to 100 LD(50)'s of S. aureus Smith suspended in mucin. Increasing as well as decreasing the immunizing dose resulted in significantly less protection.

Animals↗
PubMed1958

The cation content of phospholipides from swine erythrocytes.

Phospholipides from swine erythrocytes were isolated and separated into four reproducible fractions. One of the fractions seems to be pure phosphatidylserine. The others are almost certainly not single compounds, although the analytical data indicate that they represent mixtures considerably simpler than the parent mixture extracted from the cells. All four fractions contained Na(+) and K(+), but very little Ca(2+). Sodium was the predominant cation in two of the fractions under all conditions although the major intracellular cation was potassium. In the other two fractions the ratio Na/K varied with the extraction procedure largely because the quantity of K(+) seemed to depend on the solvent system used. There appear to be reasons to believe that the entire system of phospholipides binds Na(+) preferentially. In addition, it was observed that the quantity of Na(+) found in the lipide extracts varied when the extrusion of Na(+) from the cells was made to vary. Both of these observations are consistent with the possibility that the phospholipides play some part in the extrusion of Na(+) from these cells.

Animals↗
PubMed2004

A review of measurements of radionuclides in members of the public in the UK.

This paper summarises a comprehensive review of radio-analytical data from autopsy, whole or partial body monitoring and the assay of teeth, foetuses and urine for non-occupationally exposed members of the public in the UK between 1957 and 2003. Most attention has been given to measurements of artificial radionuclides formed in the nuclear fuel cycle, uranium and thorium. The review concentrates on measurements on people in the UK who live or have lived in the vicinity of nuclear power sites. When UK data are unavailable, or for the purposes of comparison, information has been included from studies in other countries. Highlights of key findings of the document are listed: The concentrations of strontium-90 in bone and teeth have reflected changes in the amounts present in the environment due to fallout from nuclear testing. There are higher concentration levels of 239+240Pu in samples from West Cumbria compared with the rest of the UK. However, the levels are so low that any increase in risk of induced skeletal tumours (including leukaemia) would be very small compared with those arising from the intake of natural radionuclides. As expected there have been only a few published autopsy studies. Both tissue sample mass and radionuclide concentrations were low, leading to relatively large measurement uncertainties. Whole body measurements of 137Cs in residents in Berkshire and Oxfordshire clearly show the effect of atmospheric testing of nuclear weapons and of the Chernobyl accident. A survey of whole body 137Cs and 134Cs content following the Chernobyl accident showed that residents of Central Scotland, North-West England and North Wales had twice the radiocaesium content of residents in the rest of England and Wales. Measurements of 131I in the thyroid have been reported following the accidents at Windscale and Chernobyl for most regions of the UK. Few excretion studies have been reported although this does not diminish their importance. One study on the urinary excretion rate of 90Sr in adults and children living in the Dounreay area suggested that the results did not support this radionuclide as being the cause of increased childhood leukaemia. Similar conclusions were drawn from another study involving the assay of 239Pu. It is suggested that a national database of measurements made on members of the public should be initiated. The database would provide a means for identifying future trends.

Adolescent↗
PubMed1997

Sources of data for pharmacoepidemiological studies of child and adolescent psychiatric disorders.

In view of the dramatic shift to managed care models for United States health care delivery, reliable information on the prevalence and variations in psychopharmacological drug therapies for youth in community practice settings is essential. Pharmacoepidemiology, the study of medication use in large populations, aims to accomplish that challenging task. This article offers child psychopharmacologists a brief introduction to data sources for pharmacoepidemiology. Knowledge of these data sources combined with epidemiological methods for data analysis is a beginning step to assess the psychotropic medication prescribing patterns of community physicians. This review is organized in the following sequence: (1) characteristics of the "usual practice environment" according to setting, patient population, and physician characteristics; (2) validity issues related to data sources and their potential for outcomes research; (3) data sources divided into primary and secondary types that are described in terms of their features, advantages, and limitations, followed by examples of selected applied studies using such information; (4) procedures for analyzing secondary data; (5) data analytic and longitudinal approaches; and (6) access, confidentiality, and funding. A goal for future investigators in this emerging field is to develop applied research that is clinically sophisticated, methodologically sound, and public health-minded.

Adolescent↗
PubMed1997

Development of a biodegradable ureteric stent: surface modification and in vitro assessment.

The aim of the present study was to develop a short bioresorbable ureteric stent and to characterize the chosen polymers with respect to surface modification, biocompatibility, and loading of a biologically active compound. As materials for the stent, poly(D,L-lactide) and poly(D,L-lactide-co-glycolide) were chosen. Degradation experiments were carried out and analytical data were obtained by contact angle measurement, X-ray photoelectron spectroscopy (XPS), and infrared spectroscopy in the attenuated reflection mode (FTIR-ATR). Gas loading technology was used to incorporate biologically active compounds, and biocompatibility of the polymers was assessed by in vitro cellular assays, applying measures such as cell morphology, proliferative activity, and membrane integrity. Our results indicate that surface modification of bioresorbable polymers is a suitable and efficient approach to improve the surface properties. Incorporation of biologically active compounds was possible without loss of activity, and in vitro assessment of cellular responses demonstrated the biocompatibility of the chosen polymers and modifications.

Absorption↗
PubMed1990

Proposed structures for an amino-dimethylimidazofuropyridine mutagen in cooked meats.

New analytical data allow the structure of a potent mutagen previously reported present in cooked meats to be proposed. The mutagen was isolated from a fried mixture of beef, creatine and milk, simulating a meat recipe previously shown to produce this compound. High-resolution mass spectra indicate a mol. wt of 202 and the formula C10H10N4O. Mutagenic activity was 10,000 TA1538 revertants per microgram in the Ames Salmonella test. From the NMR data, peaks showing an amino group at 6.812 p.p.m. and an N-methyl group at 3.520 p.p.m. were found, typical for the amino-imidazo structure commonly found in cooked meats. Additional signals at 2.440 p.p.m. (three protons), 7.653 (one proton) and 6.531 (one proton) were observed. A structure of 2-amino-(1 or 3),6-dimethylfuro[2,3(or 3,2)-e]imidazo- [4,5-b]pyridine was proposed based on the mass and NMR spectral data and comparison to literature compounds. The methylimidazofuropyridine reported here is probably related to another mutagen in cooked meats with a mol. wt of 216 with an additional methyl group on either the furan or pyridine rings.

Animals↗
PubMed1992

Increased exposure to dietary amines and nitrate in a population at high risk of oesophageal and gastric cancer in Kashmir (India).

Analytical data on aliphatic amines and nitrate from the most commonly used fresh and sun-dried vegetables, red chillies and a widely consumed beverage, salted tea, are presented from a high risk area for oesophageal and gastric cancer in Kashmir. Exposure estimates for the adult population show that high consumption of boiled Brassica vegetables leads to a high nitrate intake of 237 mg/day. The frequent consumption of hot salted tea is shown to result in exceptionally high exposure to methylamine (1200 micrograms/day), ethylamine (14,320 micrograms/day), dimethylamine (150 micrograms/day) and diethylamine (400 micrograms/day). The indiscriminate use of red chillies in the area leads to exposure to dimethylamine (280 micrograms/day), pyrrolidine (517 micrograms/day) and methylbenzylamine (40 micrograms/day). This is to our knowledge the first report where a chronic exposure to methylbenzylamine has been shown in a population at high risk of oesophageal cancer.

Adult↗
PubMed2003

Prevention of heterocyclic amine-induced DNA damage in colon and liver of rats by different lactobacillus strains.

The aim of the present study was to investigate the impact of four different lactobacillus (LB) strains, namely Lactobacillus bulgaricus 291, Streptococcus thermophilus F4, S.thermophilus V3 and Bifidobacterium longum BB536, which are used for the production of yogurt, on the DNA-damaging effects of heterocyclic aromatic amines (HCAs). Male F344 rats were treated orally with HCA mixtures containing 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, 2-amino-3,4,8-trimethyl-3H-imidazo[4,5-f]quinoxaline, 2-amino-9H-pyrido[2,3-b]indole and 2-amino-3-methyl-3H- imidazo[4,5-f]quinoline, which were representative of the HCA contents found in fried beef ('beef mix') and chicken ('chicken mix'). Suspensions of LB were given by gavage to the animals simultaneously with and at different time periods before administration of the HCAs. Subsequently, the extent of DNA migration was measured in colon and liver cells in single cell gel electrophoresis (SCGE) assays. All four strains caused complete inhibition of DNA damage induced with beef mix after administration of 1 x 1010 LB cells/animal, whereas with chicken mix only marginal (non-significant) effects were seen. The inhibition of beef-induced DNA damage was dose dependent and was still significant when 1 x 107 cells/animal were administered. Kinetics studies showed that the protective effects were still significant when LB was given 12 h before the beef mix. A comparison of the present results with chemical analytical data from in vitro experiments suggests that the strong reduction in DNA migration seen in the animals can be only partly explained by direct binding effects. The results of the present study show that LB are highly protective against the genotoxic effects of HCAs under conditions which are relevant for humans and provide a possible explanation for the reduced colon cancer rates observed in some studies in individuals with either high LB counts in their feces or with a high consumption of LB-containing foods.

Amines↗
PubMed1996

Assessment of conducting polymer odour sensors for agricultural malodour measurements.

The major odoriferous components of fresh pig slurry were identified using gas chromatography coupled to mass spectrometry. From the analytical data, a standard artificial slurry was reconstituted. The performance of conducting polymer odour sensor arrays was evaluated using the individual chemical volatile components and the artificial slurry itself. Most of the components are discriminated from each other, when presented singly to the sensor array. The sensors are not poisoned by the chemicals and give reproducible responses over a 3 month period. The odour components being detected from an artificial alkaline pig slurry appear to be associated with patterns obtained from indole, skatole and ammonia. The intensity of the signal is proportional to the concentration of the volatiles presented to the sensor. The results indicate that conducting polymer sensor arrays show promise for measurement of agricultural malodours, and may complement olfactometric techniques.

Acetic Acid↗
PubMed2001

Evaluation of the key odorants of foods by dilution experiments, aroma models and omission.

The state of the art in aroma analysis is reviewed with emphasis on aroma-recombination studies using synthetic blends of odorants (aroma models) which have been prepared on the basis of analytical data. The model that matches the original aroma is the starting material for omission experiments which are performed to establish the odorants that actually contribute to the aroma. These experiments are discussed in detail for the aromas of two wine varieties, three olive oils of different provenance, French fries, boiled beef and coffee. The results indicate that odorants with higher odour activity values (OAV, the ratio of the concentration to the odour threshold) are frequently essential for the aroma. However, there are exceptions where odorants with high OAVs are suppressed in the aroma and compounds with lower OAVs are important contributors. These findings are discussed in the light of model experiments which have been reported in the literature to obtain an insight into the perceptual interactions of odorants in mixtures.

Chromatography, Gas↗
PubMed1979

Trenbolone acetate and trenbolone: trace analysis in animal chow, wastewater and human urine by high pressure liquid chromatography and electron capture gas chromatography.

Analytical methodology is described for determining residues of the synthetic anabolic steroid trenbolone acetate (TBA) and its hydrolysis product trenbolone (TBOH) in admixture in animal chow, human urine, and wastewater. Benzene extracts of the substrates are subjected to liquid-liquid partitioning, further cleanup on a column of silica gel, and direct analysis by high pressure liquid chromotography or derivatization with pentafluoropropionic anhydride and analysis by electron capture gas chromatography. Satisfactory recoveries were obtained with both compounds from all three substrates. Residue levels of TBA and TBOH as low as 0.32 and 0.04 ppm, respectively, could be detected in chow; about 0.6 ppb of each compound could be detected in urine and wastewater. Thin layer chromatographic behavior of the two compounds in 7 solvent systems and other ancillary analytical data are also presented.

Acetates↗
PubMed2002

Polymer-additive extraction via pressurized fluids and organic solvents of variously cross-linked poly(methylmethacrylates).

Variously cross-linked poly(methylmethacrylates) (PMMAs) are synthesized with three additives incorporated at theoretically 1000 microg of the additive per gram of prepared polymer. The additives are Irganox 1010, Irganox 1076, and Irgafos 168. The in-house" synthesized polyacrylates are then subjected to supercritical fluid extraction (SFE) to determine if additive recovery is a function of percent cross-linking. Although considerable work in this regard has been performed with non-cross-linked polyolefins, the literature is lacking regarding polyacrylates. Some additive degradation apparently occurs during the synthesis, as judged by the increased complexity of the extract high-performance liquid chromatographic trace and the low percent recoveries observed especially for the Irganoxes. For low polymer cross-linking (1%), it appears that both PMMA synthetic reproducibility and readily observed polymer swelling during SFE are serious issues that adversely affect additive percent recovery and precision of results. Higher percent cross-linking yields more consistent analytical data than low percent cross-linking, even though the amount of additive extracted in all PMMA samples (regardless of cross-linking percentage) is essentially the same whether the extraction is via SFE or liquid-solid extraction with methylene chloride. Results for comparably cross-linked poly(ethylmethacrylate) and poly(butylmethacrylate) are similar to PMMA.

Journal Article↗
PubMed2004

An Overview of Traditional Chinese Herbal Formulae and a Proposal of a New Code System for Expressing the Formula Titles.

Traditional Chinese herbal therapy can be characterized by the use of a large number of multi-herb formulae. To provide modern and Western scientists without knowledge of Chinese literature and cultural background easy access to information, a database with a total of 11 810 traditional Chinese herbal formulae was constructed. All the information was then translated into understandable scientific terms in English. While coining the formula titles in English, we discovered some principles governing the naming of titles by using computer analysis. In addition, we observed that about 92% of the formulae are in the range of single-herb formulae to thirteen-herb formulae. Most large number-herb formulae are formulated by combining pre-existing smaller number-herb formulae. The King herbs () with major therapeutic activity in a multi-herb formula were identified by the formulation concept using two parameters: the herbal dose and the herbal drug property (the degree of toxicity). Based on such analytical data, we established an English code system representing all formula titles written in ideographic Chinese characters: an array of important key words such as 'Herbal name in Latin + Efficacy (Target organs) + Preparation form + Number of herbs.' By searching the English version of the database with any of the above key words, a variety of information on the status of traditional Chinese herbal therapy can be accessed.

Journal Article↗
PubMed2003

Personality structure and process, variance between and within: integration by means of a developmental framework.

Hooker and McAdams (2003) offer a six-foci model of personality organized around the concepts of structure and process. The structure and process distinction is essentially one of emphasizing within- or between-person variance, yet both types of variance are valuable, especially in personality development. Cattell (1966) understood the distinction and incorporated it into his concept of the data box. Hooker and McAdams's model shares aspects of Cattell's scheme but is more explicitly developmental. We argue that the concept of the developmental trajectory fits neatly into both the Cattell and Hooker-McAdams models and affords a data analytic framework for understanding both within- and between-person variance, allowing greater integration of process and structure approaches.

Aged↗
PubMed1989

Endocrine profiles and luteal function during GnRH-analogue/HMG therapy.

We have found a significant improvement of pregnancy rates after pretreatment with an agonist of gonadotrophin releasing hormone (GnRH-a). The pregnancy rate in patients treated with HMG/HCG was 17% per patient and 5.5% per cycle, in patients treated with buserelin, 25% per patient and 15% per cycle and in the triptorelin group 25% per patient and 22% per cycle. From 740 HMG/HCG cycles without GnRH-a only 66% were sufficient according to the analytical data. In 16% we found a premature LH discharge and in 18% an irregular LH fluctuation during stimulation. It is clear that gonadotrophin stimulation during pituitary suppression provokes a more intense ovarian reaction with respect to the number of follicles, as well as the endocrine activity. There are also some important practical advantages: ovarian stimulation can be started without any respect to a definite time of menstruation or of the cycle. Of further importance is the much greater flexibility in the timing of HCG administration. Finally, it will be favourable for all patients who need ovulation induction, especially for oocyte retrieval for IVF or GIFT, because no cycle has to be cancelled.

Anovulation↗
PubMed1995

Analysis of cancer rates using excess risk age-period-cohort models.

BACKGROUND: Recently the age-period-cohort (APC) model has become a popular epidemiological tool. However, it is well known that the model suffers from the identifiability problem. The simple multiplicative formulation of the model in terms of the age, period, and cohort variables without resorting to the underlying biology also casts doubt on the interpretability of the model parameters. METHODS: Excess risk APC models for cancers are developed based on carcinogenesis processes in human populations. These models have the beneficial feature of biological plausibility and do not suffer from the identifiability problem. Apart from the age, period, and cohort effects, a new kind of effect, the impact effect, is also introduced into the models. A computer program has been developed to fit the models which contain non-linear as well as restricted parameters. RESULTS: Two published mortality datasets are used to demonstrate the methodology. The proposed models fit better than the conventional APC model in both examples. CONCLUSIONS: Despite all the merits of the proposed models, several statistical issues should be investigated further before accepting this methodology as a general data-analytical tool.

Adult↗
PubMed1997

Confirmation of ethanol compressed gas standard concentrations by an NIST-traceable, absolute chemical method and comparison with wet breath alcohol simulators.

This study compares compressed-gas Ethanol Breath Standards (EBS) with wet simulators as calibration standards for breath alcohol analyzers. After reviewing the technical basis and traceability for the two calibration sources, new analytical data verifying the ethanol content of EBS gas are presented. Based on collection of ethanol in an impinger and titration using a modified California Department of Health method, the data confirm the alcohol content of EBS compressed gas standards by an absolute, wet chemical method. These results establish the concentration accuracy and the NIST traceability of the EBS gas by two independent methods, gas chromatographic analysis traceable to NIST standards and the new wet chemical method. Effluent gas from a wet simulator standard is then analyzed by the wet method to show its equivalence with EBS gas.

Breath Tests↗