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Results for “Essential elements”

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PubMed1987

Effect of dietary silicon and aluminum on silicon and aluminum levels in rat brain.

This preliminary study was undertaken to investigate the effect of dietary silicon and aluminum on levels of these elements in brain. Two ages of rats, 22 day and 10 month, were assigned to 1 of 4 diets: 1) low silicon; 2) low silicon plus aluminum; 3) silicon supplemented; and 4) silicon supplemented plus aluminum. Rats were 23 and 28 months old upon termination of the experiment. Twelve brain regions were analyzed for silicon and aluminum. Regional variations in silicon, which were independent of dietary silicon supplementation, suggest that silicon may be an essential element in brain. Aluminum supplementation decreased the silicon content in selected brain regions, including those thought to be involved in Alzheimer disease. A relationship has been established between silicon, aluminum and age. In 23-month rats, aluminum supplementation did not increase brain aluminum content. By contrast, in 28-month rats, aluminum supplementation of the low silicon diet increased brain aluminum content in most regions. No increase occurred in silicon supplemented groups of the same age. Dietary silicon supplementation thus appeared to be protective against aluminum accumulation in aging brain.

Aging↗

PubMed1996

Teaching the craft of operative surgery.

(a) Recent changes in practice and organisation of surgery make it even more important than formerly to focus attention on the acquisition of operative skills. Once the elements of good operative technique are inculcated, the trainees need practice to establish and refine the natural skill patterns that convert competence into mastery. As opportunities to acquire practical operative experience diminish in Britain, we should encourage our future surgeons to spend a period in less affluent countries where there is a heavy workload of predominantly open surgery. At present such periods are too often dismissed as 'experience, not training'. (b) Apprenticeship remains the essential element for acquiring the craft skills. Apprenticeship does not imply merely allowing trainees to watch and assist. They must also perform under supervision while being assisted by the master. (c) Craft workshops are valuable adjuncts for formal instruction and 'hands on' experience as a preliminary to continued practice of the skills. They allow the principles of good surgery to be formally stated and reinforced. (d) We do not yet have objective tests of operative skill and should not judge trainees at an early stage, except in their adherence to accepted precepts and by their results. (e) Those of us who are privileged to train the next generation of surgeons should critically assess the standards of our own technique, not just in relation to our surgical success but also to the standards we are passing on to our successors.

Education, Medical, Graduate↗

PubMedDate not supplied

Both upstream and intragenic sequences of the human neurofilament light gene direct expression of lacZ in neurons of transgenic mouse embryos.

Initial expression of the neurofilament light gene coincides with the appearance of postmitotic neurons. To investigate the molecular mechanisms involved in neuron-specific gene expression during embryogenesis, we generated transgenic mice carrying various regions of the human neurofilament light gene (hNF-L) fused to the lacZ reporter gene. We found that 2.3 or 0.3 kb of the hNF-L promoter region directs expression of lacZ in neurons of transgenic embryos. Addition of 1.8 kb hNF-L intragenic sequences (IS) enlarges the neuronal pattern of transgene expression. The 2.3-kb hNF-L promote lacZ-IS construct contains all regulatory elements essential for both spatial and temporal expression of the hNF-L gene during embryogenesis and in the adult. The use of a heterologous promoter demonstrated that the 1.8-kb hNF-L intragenic sequences are sufficient to direct the expression of lacZ in a NF-L-specific manner both temporally and spatially during development and in the adult. We conclude that these hNF-L intragenic sequences contain cis-acting DNA regulatory elements that specify neuronal expression. Taken together, these results show that the neurofilament light gene contains separate upstream and intragenic elements, each of which directs lacZ expression in embryonic neurons.

Animals↗

PubMed2002

[Determination of trace elements in lychee of different growth periods].

Conditions for determination of multi-trace elements simultaneously in lychee fruit by ICP-AES. Al, Ba, Cr, Mg, Mn, Sr, Mo, Pb, Se, Zn, Fe, Cu and Ca in different parts and different growth periods of lychee fruit in Dongguan area were determined, relative standard deviation of the method is between 1.3%-4.9%, and recovery is between 89%-124%, analytical results were satisfactory. And compared the concentration and distribution of those trace elements with those in other areas. We find that the concentration of Mo in lychee fruit sample we determine is much lower, which implies that we can improve the production and quality of lychee by applying Mo to the tree. Some elements essential to human such as Zn, Fe, Mg and Ca are high in lychee fruit, implied that nutritive value of this fruit breed is higher.

Calcium↗

PubMed1997

[Current treatment of malignant epithelial tumors of the ovary].

Surgery is the essential element of staging and treatment of malignant ovarian tumours. Regardless of the stage, it must include peritoneal cytology, hysterectomy with bilateral adnexectomy, omentectomy, pelvic and lumbo-aortic lymphadenectomy, appendicectomy and multiple peritoneal biopsies. In stage I tumours, in young women desiring a subsequent pregnancy, preservation of the uterus and contralateral ovary can be proposed. In stages II, III and IV, the therapeutic strategy consists of primary surgery and systematic chemotherapy (6 cycles). Radical surgery is essential in these cases, as the size of the residual tumour at the end of operation constitutes the major prognostic factor. To optimize the quality of tumour debulking, the maximum of visible carcinomatous nodules must be resected with, if necessary, gastrointestinal resections. The value of second-look surgery, after 6 cycles of chemotherapy, is currently controversial: it is only indicated in the context of randomized trials. Borderline malignant ovarian tumours have a good prognosis regardless of their stage. Surgery can very often be conservative, particularly in young women. Adjuvant chemotherapy has been shown to be effective in these tumours. Many studies are underway to define the value of new cytostatic molecules and "interval" surgery (intercalated between several courses of chemotherapy).

Adult↗

PubMed1976

Management of mutilating injuries of the hand.

In the devastating destruction of parts associated with mutilating injuries of the hand, it is often not possible to salvage the elements essential to normal function of the hand. The objective of primary treatment is re-establishment of circulation to the devitalized part, realignment of the remaining skeletal structures, and skin cover of the denuded portions. Definitive reconstruction has to be delayed until survival of the salvaged parts is assured. Occasionally, complex procedures have to be carried out to convert a marginal remnant of the hand into a useful functional unit. These may comprise rearrangement of bony elements to provide a radial digit with intervening space to permit pinch and grasp. Lack of sensibility can be corrected by shifting neurovascular pedicle or by immediate transfer of free neurovascular flap from a distance. Challenge met by skill, tempered by knowledge and sound judgment, comprise the elements of reconstructive hand surgery in the face of mutilating trauma. It is a field in which the surgeon is continually reminded of humility and yet it is filled with rewards for both patient and plastic surgeon.

Adult↗

PubMed2003

Expression of a structurally unique osteoclastic protein-tyrosine phosphatase is driven by an alternative intronic, cell type-specific promoter.

An osteoclastic protein-tyrosine phosphatase (PTP-oc), essential for osteoclast activity, shows sequence identity with the intracellular domain of GLEPP1, a renal receptor-like transmembrane PTP. PTP-oc has been assumed to be a truncated variant of GLEPP1, resulting from alternative splicing. However, the 5'-untranslated region sequence of PTP-oc mRNA contains 217 bp from an intron of GLEPP1. There are no splicing acceptor sites at the PTP-oc transcription site. The intronic sequence flanking the 5' end of the PTP-oc transcription start site contains potential promoter elements essential for transcriptional initiation. To test the hypothesis that the PTP-oc gene has an alternative, tissue-specific, intronic promoter, the promoter activity of a 1.3-kb PCR fragment covering the 5'-flanking region of the PTP-oc gene was measured. The putative PTP-oc promoter fragment showed strong promoter activity in U937 cells. Mutation of the putative TATA box within the PTP-oc promoter abolished 60-90% of its promoter activity. The PTP-oc promoter fragment showed strong promoter activity in cells that express PTP-oc (U937 cells and RAW264.7 cells) but not in cells that do not express the enzyme (skin fibroblasts, TE85 cells, and HEK293 cells). These findings strongly support the conclusion that the 1.3-kb intronic fragment contains the tissue-specific, PTP-oc proximal promoter. Deletion and functional analyses indicate that the proximal 5' sequence flanking the TATA box of the PTP-oc contains potential repressor elements. The removal of the putative repressor elements led to the apparent loss of tissue specificity. In summary, we conclude that an intronic promoter within the GLEPP1 gene drives the expression of the PTP-oc in a cell type-specific manner. This GLEPP1/PTP-oc gene system is one of the very few systems in which two important tissue-specific enzymes are derived from the same gene by the use of alternative intronic promoters.

Alternative Splicing↗

PubMed2005

Bio-accumulation of some trace metals in the short-neck clam Paphia malabarica from Mandovi estuary, Goa.

Monthly collections of the clam Paphia malabarica were made for period of 1 year from May 2002 to April 2003 from Verem, Mandovi estuary, Goa. Clams were categorised into two groups, 25-35 mm (small size) and 35-40 mm (big size). Significant difference was not observed in the accumulation of metals in the whole soft tissue between the two size groups. Irrespective of size, annual mean, metal content recorded as microg/g dry weight in the whole soft tissue was 3.8, 30.3, 13.5, 36.6 and 105.7, respectively, for Cd, Pb, Cu, Zn and Fe. Of the two toxic elements Cd and Pb, Cd content was almost uniform throughout the year except for a rise in September for the small size and October for the big size. Pb, on the other hand, was low from the beginning of the monsoon and exhibited distinct accumulation from December onwards up to April, May and, to some extent, June. The pattern was similar in both the size groups, the values being higher for the bigger size group. The three essential elements Cu, Fe and Zn exhibit trends similar to one another with peaks in September and December-January in both the size groups. Cadmium accumulation was highest in the mantle and adductor muscle, Lead, in foot, Copper, in digestive gland and gonad, and Zn and Fe, in gills. Correlation coefficient between different metal couplings as tested statistically revealed significant coupling for Zn-Fe (r 0.92) in the bigger size group, the same was observed between Cu-Fe (r 0.62) and Cd-Zn (r 0.94). Seasonal difference in Pb accumulation was highly significant.

Animals↗

PubMedDate not supplied

Intervention research: establishing fidelity of the independent variable in nursing clinical trials.

BACKGROUND: Internal validity of a randomized clinical trial of a nursing intervention is dependent on intervention fidelity. Although several methods have been developed, evaluating audio or audiovisual tapes for prescribed and proscribed interventionist behaviors is considered the gold standard test of treatment fidelity. This approach requires development of a psychometrically sound instrument to meaningfully categorize and quantify interventionist behaviors. OBJECTIVE: To outline critical steps necessary to develop a treatment fidelity instrument. METHODS: A comprehensive literature review was conducted to determine procedures used by other researchers. The literature review produced five quantitative studies of treatment fidelity, all in the field of psychotherapy, and two replication studies. A synthesis of methodologies across studies combined with researchers' experiences resulted in identification of the steps necessary to develop a treatment fidelity measure. RESULTS: Seven sequential steps were identified as essential to the development of a valid and reliable measure of treatment fidelity. These steps include (a) identification of the essential elements of the experimental and control treatment modalities; (b) construction of scale items; (c) development of item scaling; (d) identification of the units for coding; (e) item testing and revision; (f) specification of rater qualifications and development of rater training program; and (g) development and completion of pilot testing to test psychometric properties. Development of the Possibilities Project Psychotherapy Coding Questionnaire is described as an illustration of the seven-step process. DISCUSSION: The results show the essential steps that are unique to the development of treatment fidelity measures and show the feasibility of using these steps to construct a psychometrically sound treatment-specific fidelity measure.

Adolescent↗

PubMed1981

The concentration of the elements Zn, Cu, Mg, Fe, Na, K in human amniotic fluid during birth.

In order to determine the influence of the course of pregnancy and exogenous factors on the quantitative distribution of the cations sodium, potassium, magnesium, zinc, copper and iron in amniotic fluid, these cations were assayed in the amniotic fluid of 197 pregnant women with atom absorption spectrophotometry. There were 124 normal pregnancies, 34 with toxemia, 23 with green amniotic fluid and 15 smokers. The results of sodium, potassium, and magnesium concentrations correspond well with values found by other authors. In contrast, normal mean values for zinc, copper, and iron are different from those published to date. The course of pregnancy and exogenous factors do not influence sodium concentration in the amniotic fluid. Smokers when compared with normal controls showed a significantly increased potassium in green amniotic fluid. Magnesium concentration in green amniotic fluid is also significantly increased. Similarly, values for zinc, copper and iron in pathologic amniotic fluid was significantly above normal means. This corresponds to the significantly decreased in copper and zinc values in blood and serum of newborns and infants in various disease states. The essential elements zinc, copper and magnesium are important both for the course of pregnancy as well as for the development of fetus and newborn. APGAR and others have indicated the importance of the replacement of bioelements, especially zinc, during pregnancy. We also may conclude that during pregnancy essential cations should be determined in serum or better yet in avoid the pathophysiologic consequences of severe cation disturbances in mother and infant by appropriate replacement therapy.

Amniotic Fluid↗

PubMed1998

Distribution of 14 elements in tissues and organs of oceanic seabirds.

The concentrations of 14 trace elements (Li, V, Mn, Co, Cu, Zn, Se, Rb, Sr, Ag, Cd, Cs, Pb, and Hg) were determined in tissues and organs of three species and in the liver of 11 species of seabirds. Comparatively high concentrations of Li, Co, Sr, and V were found in the femur. Cd, Se, Cu, and Mn concentrations were relatively higher in the kidney than in other tissues and organs. Rb, Cs, and Pb concentrations were rather uniform among tissues. Concentrations of essential elements such as Mn, Cu, and Co were comparable among seabird species, except high Cu concentrations in northern giant petrel. Among nonessential elements, concentrations of Cd and Hg were variable according to seabird species. Pb levels were low in all the species. High Se levels (100 microg/g dry weight) were found in the liver of black-footed albatross and grey petrel. There were significant positive correlations between Se and Cd concentrations in three species and between Se and Hg in black-footed albatross, suggesting that Se has an antagonistic action on the toxic effects of Cd and Hg. Concentrations of Li, V, Ag, and Cs were usually low (less than 1 microg/g dry weight).

Animals↗

PubMed2005

Variations in the level of some trace elements in hair of participants in the Italian expeditions in Antarctica.

As a part the Italian National Programme of Research in Antarctica (PNRA) a monitoring study has been undertaken to quantify the concentrations of some selected trace elements in human hair of participants in the Antarctic expeditions. Such concentrations may vary as a consequence of the extreme environmental conditions and changes in lifestyle experienced by participants in the expeditions, as some evidence in previous investigations seems to suggest. The present study regards samples collected on the occasion of the 2002-2003 expedition to the Italian Base of Terra Nova Bay (now Mario Zucchelli Base), i.e., just before the expedition and about one month later. Seven essential elements were taken into account, namely, Ca, Cu, Cr, Fe, Mg, Mn and Mo. Determinations were performed by Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) and Dynamic Reaction Cell Inductively Coupled Plasma Mass Spectrometry (DRC-ICP-MS). Data obtained were statistically treated by using the non-parametric Friedman test. The concentrations of Ca, Cu and Mg were found to decrease (P < 0.05). The stress caused by the severe environmental conditions might well play a role in the observed decrease.

Antarctic Regions↗

PubMedDate not supplied

Ineffectiveness of nickel in augmenting the hepatotoxicity in protein deficient rats.

This study was designed to determine the toxic effects of nickel sulfate on the biochemical and elemental profile of liver in protein deficient rats. Nickel sulfate in the dose of 800mg/l in drinking water was administrated to Sprauge Dawley (S.D) normal control as well as protein deficient rats for a total duration of eight weeks. The effects of nickel treatment and protein deficiency when given separately and in combination were studied on rat liver marker enzymes like Alkaline phosphatase (ALP),Glutamate oxaloacetate transaminase (GOT), Glutamate pyruvate transaminase (GPT) and also on the status of essential elements in rat liver. Protein deficient, Ni treated as well as combined protein deficient and nickel treated rats showed significant reductions in the body weight and hepatic protein contents as compared to normal control rats. Hepatic alkaline phosphatase activity and alanine aminotransferase showed a significant elevation in rats subjected to protein deficiency, nickel treatment and combined protein deficiency and nickel treatment. As regards to hepatic levels of aspartate aminotransferase a significant elevation was observed in protein deficient and nickel treated protein deficient animals. Nickel administration to normal and protein deficient rats has resulted in a significant increase in concentrations of nickel, phosphorus and sulfur in liver tissue. The concentration of zinc and copper in liver tissue decreased significantly in protein deficient, nickel treated and nickel treated protein deficient animals. Tissue iron concentrations were found to be decreased in protein deficient animals, but the concentrations of iron got elevated significantly in nickel treated and nickel treated protein deficient animals. It has been observed that selenium got decreased significantly in protein deficient, nickel treated and nickel treated protein deficient animals when compared to normal animals. The elevation of selenium in nickel treated protein deficient animals was also significantly higher when compared to protein deficient animals.

Animals↗

PubMed1983

Use of spleen organ cultures in the analysis of hemopoietic alterations induced by irradiation and allogeneic marrow transplantation.

The transplantation of 0.5-1 X 10(7) BALB/c mouse bone marrow cells into lethally irradiated CBA recipient mice and the subsequent explantation of the recipient spleens resulted in active hemopoietic progenitor cell (colony forming cell; CFC) regeneration in organ cultures but not in vivo. In order to establish what hemopoietic elements essential for CFC regeneration are altered in vivo as a consequence of allogeneic donor/recipient interactions, the ability of spleens to support CFC regeneration in organ cultures was analysed when these were removed from irradiated recipients at various time intervals after allogeneic marrow transplantation. It was found that an inhibition of differentiation of hemopoietic stem cells (CFUs) and committed hemopoietic progenitor cells (CFC) occurred initially in allogeneic marrow graft recipients followed by an alteration of growth supportive spleen stromal elements. The latter appears to consist of at least two distinct components: a nonspecific component and a specific component with the features of immunologic memory.

Animals↗

PubMed1986

An estrogen-responsive element derived from the 5' flanking region of the Xenopus vitellogenin A2 gene functions in transfected human cells.

In the human breast cancer cell line MCF-7, we observe estrogen induction of the stable transfected Xenopus vitellogenin A2 gene. An estrogen-responsive element (ERE) could be defined by using a vitellogenin-chloramphenicol acetyltransferase hybrid gene in transient transfection experiments. The ERE is located in the 5' flanking region and is able to confer estrogen inducibility to the thymidine kinase gene promoter. By 5' and 3' deletions we have determined a 35 bp sequence sufficient for high stimulation by estradiol. Even 18 bp give a small estrogen response. The 35 bp ERE contains the palindromic sequence 5'GGTCACAGTGACC-3' as an essential element. The fact that the ERE of a frog gene functions in human cells demonstrates that signals and factors involved in the control have been conserved during evolution.

Acetyltransferases↗

PubMed1981

Simian virus 40 tandem repeated sequences as an element of the early promoter.

On the late side of the simian virus 40 (SV40) DNA replication origin are several sets of tandem repeated sequences, the largest of which is 72 base pairs long. The role of these sequences was examined through construction of deletion mutants of SV40. A mutant from which one of the 72-base-pair repeated units was removed is viable upon transfection of monkey kidney cells with viral DNA. Extension of this deletion into the second repeated unit, however, leads to nonviability, as recognized by the absence of early transcription and of tumor antigen production. These observations indicate that the 72-base-pair repeated sequences form an essential element in the early viral transcriptional promoter and explain the inability of such a deleted genome to complement an early temperature-sensitive mutant of SV40, tsA, as well as the failure to replicate its DNA. In a parallel experiment it was found that the extended deletion mutant was also unable to complement a late temperature-sensitive mutant of SV40, tsB. This suggests that the extended mutant is also defective in DNA replication or late transcription (or both).

Base Sequence↗

PubMed2005

[Spectrometric determination of trace elements in 'Jinguang' prunus mume var. bungo of different growth periods].

A study was carried out on the content of trace elements such as Ca, Fe, Zn, Mn and Cu of prunus mume var. bungo in different growth periods by WFX-110 atomic absorption spectrometry. The results indicated that the linear relationships of different elements within the limits of working curves are good and the range of the recovery is 98% -105%, hence showing that the results are satisfactory. The total content of these five trace elements increases as the fruit grows, but the concentration is related to the growth of fruit and fruit core, which provides us with valuable data. The contents of the trace elements essential to human body are relatively high, which shows that this fruit breed has a relatively high nutritive value.

Calcium↗

PubMedDate not supplied

[The most informative abstracts of research papers: suggestion of a model].

Considering proposals on research work writing which point out importance elements for dissemination of scientific findings, the authors have as aims testing a structured and a more informative abstract model. For a research done in Rio de Janeiro, in 1994, the quantitative method and documental analyses in 68 abstracts published in REBEn between 1990 a 1993 was applied. It has been found that the majority of indicative abstracts whose communication doesn't facilitates findings comprehension on nursing. It has been concluded that the tested model can be applied because all essential elements have been found in the majority of works that originated the investigated abstracts. So it is recommended the implementation this structured and informative model usage among the research beginners.

Abstracting and Indexing↗