SEARCH · PubMed Health

Results for “Essential elements”

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.

At least 757 records · Page 42Linked to original sources

PubMed1991

Prosthetic valve endocarditis: a continuing challenge for infection control.

Conventional medical thought accepts the risks of nosocomial prosthetic valve endocarditis (PVE) to be between 0.7 and 1.4%, the incidence within several months after surgery. More careful actuarial analysis of recent series suggests the risk of nosocomial PVE is 1.4-3.0%, with cases occurring throughout the year after surgery. Methicillin-resistant coagulase-negative staphylococci are the predominant cause of nosocomial PVE and account for 60% of cases. Intraoperative contamination by Staphylococcus epidermidis of nosocomial origin has led to small epidemics of PVE. Aside from the fundamental elements of aseptic surgical technique, studies have failed to identify elements of intraoperative or postoperative care that might be modified to reduce the incidence of sporadic cases of nosocomial PVE. Prophylactic antibiotics have become an essential element in the effort to prevent PVE. Some recent studies have advocated using cefamandole or cefuroxime for prophylaxis; however, other studies have failed to find these agents more effective than cefazolin. The use of vancomycin for prophylaxis requires additional study. Intensive studies are needed to define elements of perioperative and postoperative care that can be modified to reduce the frequency of nosocomial PVE.

Anti-Bacterial Agents↗

PubMed1997

Determination of various nutrients and toxic elements in different Brazilian regional diets by neutron activation analysis.

The concentration of 19 elements (As, Br, Ca, Cd, Cl, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Rb, Sb, Sc, Se and Zn) was evaluated in some diets taken from different regions of Brazil by Instrumental and Radiochemical Neutron Activation Analysis. Several populations with different socio-economic living conditions and inhabiting in different regions of Brazil were studied in order to estimate and to detect the variability of the mineral and toxic element content among Brazilian populational groups. The data obtained showed a significant difference between the contents of these elements in the diets from the regions studied. The general conclusions from the data obtained in this study were: 1) regarding the daily amounts of essential elements (Ca, Cl, Co, Fe, Mn, Na, K, Fe, Se and Zn), the Santa Catarina 2 diet showed the closest values when compared to the recommended values of RDA (Recommended Dietary Allowance) and/or WHO (World Health Organization). The Santa Catarina 1(low income groups) showed the lowest when compared to the same values. 2) The intake of toxic elements (As, Br, Cd, Hg, Sb) among the diets does not seem to be a major problem when compared to PTWI (Provisional Tolerable Weekly Intake, WHO), except for Hg intakes in regions near gold mining activities, like Manaus and Mato Grosso, where the values found were near the upper limit set by WHO.

Adolescent↗

PubMed1993

Free amino acids and protein in Scots pine seedlings cultivated at different nutrient availabilities.

Scots pine (Pinus sylvestris L.) seedlings of a provenance from northern Sweden were cultivated hydroponically for 7 weeks in a climate chamber. The nutrient solution contained either 2.5 (low-N) or 50 (high-N) mg N l(-1) with other essential elements added in a fixed optimal proportion to the nitrogen. After 5 and 7 weeks, the seedlings were analyzed for growth, total nitrogen and other essential nutrients, protein and free amino acids. Low-N seedlings grew more slowly and had higher root/shoot ratios than high-N seedlings. With respect to total nitrogen, the effect of the lower nutrient supply was mainly on the nitrogen content of the whole plant and the allocation of nitrogen among tissues, not on tissue nitrogen concentration. This was also the case for potassium, phosphorus, calcium and magnesium. The proportions by weight among these macronutrients in the whole seedlings were similar in both nutrient regimes. The proportion and concentration of sulfur were significantly lower in low-N seedlings than in high-N seedlings, because of a lower net uptake of sulfur than of other macronutrients. The shoot, needles and stem of low-N seedlings had higher concentrations of free amino acids and lower concentrations of protein than the shoot, needles and stem of high-N seedlings. Arginine dominated the pool of free amino acids in the low-N seedlings, whereas glutamine predominated in the high-N seedlings. We conclude that Scots pine seedlings accumulated soluble nitrogen as arginine when net protein synthesis was limited by factors other than nitrogen availability. Nutritional imbalance, as revealed by growth characteristics and a suboptimal proportion and concentration of sulfur in the seedlings, probably affected synthesis of S-amino acids, resulting in the diversion of assimilated nitrogen to arginine instead of protein.

Journal Article↗

PubMed1986

Trace elements in serum, packed cells, and dialysate of CAPD patients.

Neutron Activation Analysis (NAA) was used to investigate trace element patterns in serum, packed cells, and dialysate of CAPD patients. The concentrations of the elements Cs, Cu, Fe, and Mn in serum and packed cells appeared to be maintained within the normal range, while the levels of the non-essential element Br in both serum and packed cells were subnormal. The serum Cr values were extremely high (20 to 50 times higher than the normal serum level). The amount of Cr absorbed from the dialysate was calculated to be ten times higher than the daily dietary uptake. The Co concentrations were normal in packed cells but were significantly increased in serum. The Rb content in packed cells was slightly lower than normal, while the serum value was normal. Se was maintained within the normal range in packed cells, but the serum concentration was slightly lower than normal. The concentrations of Zn were low in serum and appeared to be higher than normal in packed cells. In conclusion, this analysis of the trace element status of CAPD patients reveals two major abnormalities. There is an apparent loss of Br from the blood towards the dialysate and on the other hand, a dramatic accumulation of Cr into the blood as a result of the very high Cr content in the dialysate.

Erythrocytes↗

PubMed2000

Positive and negative control of the expression of parathyroid hormone (PTH)/PTH-related protein receptor via proximal promoter P3 in human osteoblast-like cells.

Three promoters, P1, P2, and P3, regulate the expression of the receptor for the human PTH/PTH -related protein. The P3 promoter, proximal to the gene, seems to be turned on in many tissues and to be the most active of the three in the human adult kidney. P3 is also active in human osteoblastic SaOS-2 cells. Its structure to function relationship is, however, still poorly understood. To address this issue we assayed, in transiently transfected SaOS-2 cells, the expression of reporter gene constructs containing truncated P3 promoter fragments and substitution mutants. We thus localized cis-acting elements essential for P3 promoter activity and identified two key Sp1 binding sites. We also found in the 5'-untranslated exon U4, transcribed from promoter P3, an element that inhibits the expression of the receptor and is not promoter specific. This study provides new insights into PTH receptor expression in human osteoblast-like cells.

5' Untranslated Regions↗

PubMed2003

The first intron of the human osteopontin gene contains a C/EBP-beta-responsive enhancer.

The osteopontin (OPN) protein is found expressed at high level in several processes including fibrotic evolution of organ injuries, tumorigenesis, and immune response. The molecular mechanisms that underly overexpression, especially at the transcriptional level, have been only partially clarified. Therefore, this study was undertaken in search for additional DNA elements in the regulatory regions of the OPN gene and cognate transcription factors. Our results on the region upstream of the transcription start site confirmed that essential elements are located within the first 100 bp. Analysis of the sequence that includes the first untranslated exon and first intron revealed that it could enhance the promoter activity. Experiments of transfection of constructs containing different fragments of this sequence showed that most of the enhancer activity was confined in the terminal 30-bp tract of the first intron, although it was not functioning in a myofibroblast cell line. DNA/protein binding assays and cotransfection experiments showed that the C/EBP-beta transcription factor was able to bind a recognition sequence in this 30-bp segment. We found a bi-allelic sequence polymorphism at +245 in the first intron, which did not show a significant functional effect, but is a useful tool for future association studies.

Base Sequence↗

PubMed1987

Purified RNA polymerase II recognizes specific termination sites during transcription in vitro.

We have studied the ability of certain well-defined prokaryotic DNA sequences to act as specific termination signals for highly purified calf thymus RNA polymerase II. We used duplex DNA fragments modified to direct efficient and specific transcription of defined DNA templates to follow transcription with RNA polymerase alone in the absence of additional protein factors. Elongation of RNA chains by RNA polymerase II is processive through most DNA sequences. However, certain DNA sequences serve as effective "intrinsic" terminators for RNA polymerase II; in this they resemble the "rho-independent" terminators for the bacterial RNA polymerase. Several rho-independent bacterial terminators are also able to act as termination signals for RNA polymerase II. However, there is no apparent correlation between the efficiency of termination for the bacterial enzyme and that found for the calf thymus enzyme. One very efficient bacterial terminator (phage T7 early terminator) gives no termination with RNA polymerase II, and we have identified at least two sites that cause the eukaryotic enzyme to terminate but have no effect on transcription by the bacterial enzyme. Hence, the signals recognized as intrinsic termination sites for the two enzymes are substantially different. All of the sites that act as intrinsic terminators for RNA polymerase II contain a series of consecutive thymidine residues in the nontranscribed DNA strand (T-run), and the 3' end of the completed RNA normally lies within this sequence. It is plausible that the T-run is part of the signal for an RNA polymerase II termination site; however, there is no apparent correlation between the number of T residues and the efficiency of the terminator, suggesting that other sequence elements are required for, or modulate, termination. Several lines of evidence suggest that the formation of RNA secondary structures in the nascent transcript is not an essential element of the intrinsic RNA polymerase II termination signal.

Animals↗

PubMed1994

The PIR-International Protein Sequence Database.

PIR-International is an association of macromolecular sequence data collection centers dedicated to fostering international cooperation as an essential element in the development of scientific databases. A major objective of PIR-International is to continue the development of the Protein Sequence Database as an essential public resource for protein sequence information. This paper briefly describes the architecture of the Protein Sequence Database and how it and associated data sets are distributed and can be accessed electronically.

Amino Acid Sequence↗

PubMed1993

[Quality of services in a small hospital].

The nursing services department of a 64 bed hospital in Caraquet, New Brunswick, (serving a widespread population of 25,000 people) decided to check the quality of care offered to their patients. A search was conducted among numerous quality of care management models to find the one that best suited their needs. They chose a structured quality appraisal and management program currently being used by the Royal Victoria Hospital in Montreal. The author outlines the way quality assurance directors in this Montreal hospital empower their health care providers. The author describes the concept of quality and summarizes the oriental and occidental ideologies that influence it. The nursing staff's perception of the essential elements of quality assurance are explained and the stages are identified. The author maintains that decentralization and delegation empowers individuals and instills confidence while maintaining the essential personal touch. She believes that the organization of the future is one that will promote teamwork. She also believes that motivation, participative management and workplace satisfaction promote quality care--"care that doesn't cost a dime." This program has numerous advantages. It allows employees to fully participate in the process. It also averts potential problems, and provides employees with the ability to discover and problem solve when necessary. It also allows for the strengths and weaknesses of each service to be outlined and identified deficiencies corrected.

Humans↗

PubMed1985

Identification of a sequence element on the 3' side of AAUAAA which is necessary for simian virus 40 late mRNA 3'-end processing.

Our previous studies of the 3'-end processing of simian virus 40 late mRNAs indicated the existence of an essential element (or elements) downstream of the AAUAAA signal. We report here the use of transient expression analysis to study a functional element which we located within the sequence AGGUUUUUU, beginning 59 nucleotides downstream of the recognized signal AAUAAA. Deletion of this element resulted in (i) at least a 75% drop in 3'-end processing at the normal site and (ii) appearance of readthrough transcripts with alternate 3' ends. Some flexibility in the downstream position of this element relative to the AAUAAA was noted by deletion analysis. Using computer sequence comparison, we located homologous regions within downstream sequences of other genes, suggesting a generalized sequence element. In addition, specific complementarity is noted between the downstream element and U4 RNA. The possibility that this complementarity could participate in 3'-end site selection is discussed.

Base Sequence↗

PubMed2003

Soil-to-plant transfer factors for natural radionuclides and stable elements in a Mediterranean area.

The transfer factors (TF) for natural uranium isotopes (238U and 234U), thorium isotopes (232Th, 230Th and 228Th), and 226Ra were obtained in plant samples (grass-pasture) growing in granitic and alluvial soils around a disused uranium mine located in the Extremadura region in the south-west of Spain. Affected and non-affected areas of the mine presented large differences in the activity concentrations of radionuclides of the uranium series. We also determined transfer factors for several stable elements (essential and non-essential). A set of statistical tests were applied to validate the data. The results showed that the transfer factors for both the natural radionuclides and the stable elements are independent of the two substrate types involved and also of the two areas considered in the study.

Environmental Monitoring↗

PubMed1991

Alternative splicing in the neural cell adhesion molecule pre-mRNA: regulation of exon 18 skipping depends on the 5'-splice site.

Two isoforms of the neural cell adhesion molecule (NCAM), termed NCAM-180 and NCAM-140, derive from a single gene via inclusion or exclusion of the penultimate exon 18 (E18). This alternative splicing event is tissue-specific and regulated during differentiation. To explore its structural basis, we have analyzed the pattern of spliced mRNA generated from transiently transfected minigenes construct containing this exon and portions of the adjacent introns and exons faithfully reproduces the differentiation state-dependent alternative splicing of the endogenous pre-mRNA. By systematic deletion and replacement analysis, we scanned the minigene for the presence of functionally important cis-elements. We identified two sequences that affected differentiation state-dependent regulation. One, the central part of E18, does not seem to contain a specific cis-element essential for proper splice site choice, because extending the deletion restored correctly regulated expression of the splicing products. In contrast, the 5'-splice site is an important element for regulation. Replacing it with a corresponding sequence from the alpha-globin gene resulted in constitutive use of the optional exon. When placed in the alpha-globin gene it did not promote alternative splicing. Instead, we observed a strongly decreased efficiency of splicing of the downstream intron in undifferentiated cells. This block of splicing was partially relieved after differentiation. The results are consistent with a model in which skipping of E18 is controlled in part at the associated 5'-splice site by trans-acting factors that undergo quantitative or qualitative changes during differentiation of N2a cells.

Animals↗

PubMed1986

Structure and transforming function of transduced mutant alleles of the chicken c-myc gene.

A small retroviral vector carrying an oncogenic myc allele was isolated as a spontaneous variant (MH2E21) of avian oncovirus MH2. The MH2E21 genome, measuring only 2.3 kilobases, can be replicated like larger retroviral genomes and hence contains all cis-acting sequence elements essential for encapsidation and reverse transcription of retroviral RNA or for integration and transcription of proviral DNA. The MH2E21 genome contains 5' and 3' noncoding retroviral vector elements and a coding region comprising the first six codons of the viral gag gene and 417 v-myc codons. The gag-myc junction corresponds precisely to the presumed splice junction on subgenomic MH2 v-myc mRNA, the possible origin of MH2E21. Among the v-myc codons, the first 5 are derived from the noncoding 5' terminus of the second c-myc exon, and 412 codons correspond to the c-myc coding region. The predicted sequence of the MH2E21 protein product differs from that of the chicken c-myc protein by 11 additional amino-terminal residues and by 25 amino acid substitutions and a deletion of 4 residues within the shared domains. To investigate the functional significance of these structural changes, the MH2E21 genome was modified in vitro. The gag translational initiation codon was inactivated by oligonucleotide-directed mutagenesis. Furthermore, all but two of the missense mutations were reverted, and the deleted sequences were restored by replacing most of the MH2E21 v-myc allele by the corresponding segment of the CMII v-myc allele which is isogenic to c-myc in that region. The remaining two mutations have not been found in the v-myc alleles of avian oncoviruses MC29, CMII, and OK10. Like MH2 and MH2E21, modified MH2E21 (MH2E21m1c1) transforms avian embryo cells. Like c-myc, it encodes a 416-amino-acid protein initiated at the myc translational initiation codon. We conclude that neither major structural changes, such as in-frame fusion with virion genes or internal deletions, nor specific, if any, missense mutations of the c-myc coding region are necessary for activation of the basic oncogenic function of transduced myc alleles.

Alleles↗

PubMed2002

The role of the osteoconductive scaffold in synthetic bone graft.

Autogenous bone is regarded as the gold standard for bone graft materials as it provides 3 elements necessary to generate and maintain bone: scaffolding for osteoconduction, growth factors for osteoinduction, and progenitor cells for osteogenesis. Allograft is more limited than autograft in these essential elements and yields more variable clinical results. Composite synthetic grafts offer an alternative that can potentially unite the 3 salient bone-forming properties in more controlled and effective combinations than can be obtained in many clinical situations, without the disadvantages found with autograft. This article examines the underemphasized but crucial role of the osteoconductive scaffold in the composite synthetic bone graft.

Animals↗

PubMed1999

[Incisional hernia. Patient management. Approach to the future operated patients].

Incisional hernia, an abnormal orifice of the midline abdominal wall secondary to an operation, presents in a wide range of forms to the plastic surgeon: small orifice (< 6 cm) in a young, muscular subject, or vast defect (> 10 cm) in an obese subject who has undergone multiple operations, or who presents one or more diseases. Regardless of this presentation, the approach to the patient must always be just as rigorous, based on a precise assessment of the clinical signs. This clinical examination is irreplaceable, but is often insufficient, incomplete, and misleading. Only CT imaging of the abdominal wall provides a good analysis of the damage. Beyond the simple orifice, a large incisional hernia is responsible for a whole range of disease. This "incisional hernia disease", with its visceral and respiratory components, requires a multidisciplinary assessment. The anaesthetist and respiratory physician must assess the repercussions of this lesion and detect any risk factors. Based on this assessment, major incisional hernias (2/3 of the 350 operated patients of our series) require specific preparation involving the following elements: eradication of any site of wound infection, weight loss, muscle building, abdominal and chest physiotherapy, and pneumoperitoneum. Pneumoperitoneum according to the Goni Moreno protocol is an essential element of the preparation of the most difficult forms (irreducible, double, or complicated incisional hernias). Only this gaseous expansion of the abdomen can facilitate reintegration of the viscera and reconstruction of the abdominal wall. In our practice, the operation itself consists of 2 types of procedures: simple local abdominoplasty (e.g. Judd's technique) for small incisional hernias (about 20% of cases), or a combination of reconstitution of the deep fascia by extensive cleavage of the posterior sheath of the rectus abdominis and prosthesis. This prosthesis, which lines the fascial plane, is placed extraperitoneally. This technique, with several variants described here, is based on a similar concept to that promoted by Rives et al. and Stoppa et al. It is the preferred procedure in all large incisional hernias (80% in our experience). Patient selection, intensive preparation, meticulous technique, and intensive postoperative nursing give stable, solid results (90% of patients) and ensure optimal security, bearing in mind that repair of a large incisional hernia is always difficult and sometimes dangerous (1% mortality, 6 to 10% morbidity in all large series).

Abdominal Muscles↗

PubMed1992

[Participation of mental workload in circulatory system reaction to occupational work].

The aim of the study was to determine the degree to which the heart rate during and after work of variable physical and mental load was affected by the mental workload of moderate intensity. The subjects were 150 women aged 17-57. 24-hour recordings of their heart rates during work, leisure and sleep were taken using the Medilog recording-analysing system. Mental workload was determined in two ways: by the AET method, which enabled objective evaluation of the load, and by a method which involved subjective evaluation of work requirements and the ability to cope with them. Using the multiple regression analysis, the degree to which concurrent elements of mental and physical workload an serve as predictors of heart rate during work, leisure and sleep. The results show that physical workload is the more essential factor affecting the reaction of the circulatory system under the circumstances of concurrent mental and physical workload. By extending the measurements to involve off-duty hours, it was possible to determine that the consequences of mental workload manifested also after the work. The prolonged effect of mental workload on the heart rate was evident only when the subjective method of workload estimation was used. This points to the individual character of mental workload. The findings indicate on one hand that the share of mental workload should not be neglected during evaluation of the effects of occupational workload on the physiological reactions and, on the other, that the heart rate measurement is a useful tool for indicating essential elements of workload.

Adolescent↗

PubMed2003

A novel sequence in the coiled-coil domain of Stat3 essential for its nuclear translocation.

Stat3 is activated by cytokines and growth factors via specific tyrosine phosphorylation, dimerization, and nuclear translocation. However, the mechanism involved in its nuclear translocation is unclear. In this study, by systematic deletion and site-directed mutagenesis we identified Arg-214/215 in the alpha-helix 2 region of the coiled-coil domain of Stat3 as a novel sequence element essential for its nuclear translocation, stimulated by epidermal growth factor as well as by interleukin-6. Furthermore, we identified Arg-414/417 in the DNA binding domain as also required for the nuclear localization of Stat3. This sequence element corresponds to Lys-410/413 of Stat1, a reported sequence for Stat1 nuclear translocation. On the other hand, Leu-411 of Stat3, corresponding to Leu-407 of Stat1, a necessary residue for Stat1 nuclear transport, is not essential for Stat3 nuclear import. The mutant of Arg-214/215 or Arg-414/417 was shown to be tyrosyl-phosphorylated normally but failed to enter the nucleus in response to epidermal growth factor or interleukin-6. The defect, however, can be rescued by the wild-type Stat3 but cannot be compensated by these two mutants. Mutations on Arg-414/417, but not Arg-214/215, destroy the DNA binding activity of Stat3. Our data for the first time identified a sequence element located in the coiled-coil domain that is involved in the ligand-induced nuclear translocation of Stat3. This novel sequence together with a conserved sequence element in the DNA binding domain coordinates to mediate the nuclear translocation of Stat3.

Amino Acid Sequence↗

PubMed1990

Lack of significantly positive correlations between elemental concentrations in hair and in organs.

Elemental concentrations (Ca, Cu, Fe, Mg, P, Se and Zn) in the hair of Japanese were examined in relation to those in internal organs (cerebrum, cerebellum, heart, spleen, liver, kidney and rib). No significantly positive correlation was found between elemental concentration in hair and that in internal organ. This result indicates the restricted use of hair as a medium for the estimation of nutritional status of the essential elements examined in the present study, at least on an individual basis. The correlations between the concentrations in organs are also presented.

Bone and Bones↗