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Results for “Essential elements”

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At least 289 records · Page 16Linked to original sources

PubMed2002

H1t/GC-box and H1t/TE1 element are essential for promoter activity of the testis-specific histone H1t gene.

The testis-specific linker histone H1t gene is transcribed exclusively in mid to late pachytene primary spermatocytes. Tissue-specific expression of the gene is mediated primarily through elements located within the proximal promoter. Previous work in transgenic animals identified a unique 40-base pair promoter element designated H1t/TE that is essential for spermatocyte-specific expression. The H1t/TE element contains three subelements designated TE2, GC-box, and TE1 based on in vitro footprinting and electrophoretic mobility shift assays. Because GC-box is a consensus site for binding of Sp transcription-factor family members, experiments were performed demonstrating that two Sp family members, Sp1 and Sp3, were present in testis cells from 9-day-old and adult rats and in pachytene primary spermatocytes and early spermatids. A 95- to 105-kDa form of Sp1 is most abundant in the tissues and cell lines examined, but a 60-kDa form of Sp1 is the most abundant species in spermatocytes and early spermatids. Further examination of Sp1 and Sp3 from adult testis, primary spermatocytes, and early spermatids showed that they can bind to the H1t/TE element. In order to determine the contributions of the subelements to H1t transcription, we mutated each of them in H1t promoter luciferase reporter vectors. Mutation of the GC-box and TE1 subelement reduced expression 77% and 49%, respectively, compared with the wild-type H1t promoter in transient expression assays in a testis GC-2spd cell line that was derived from germinal cells. These studies suggest that Sp transcription factors may be involved in transcription of the H1t gene and the GC-box and the TE1 subelement are required for activation of the H1t promoter.

Animals↗

PubMed1999

Molecular mechanism of the multiple regulation of the Saccharomyces cerevisiae ATF1 gene encoding alcohol acetyltransferase.

The ATF1 gene encodes an alcohol acetyl transferase (AATase), that catalyses the synthesis of acetate esters from acetyl CoA and several kinds of alcohols. ATF1 transcription is negatively regulated by unsaturated fatty acids and oxygen. A series of analyses of the ATF1 promoter identified an 18 bp element essential for transcriptional activation. Ligation of the 18 bp element into a plasmid carrying the CYC1 promoter deleted UAS-activated transcription and conferred transcriptional repression by unsaturated fatty acids. The 18 bp element contains a binding sequence for Rap1p, which is a transcriptional repressor and activator. In vitro binding studies showed that Rap1p binds to the 18 bp element essential for transcriptional activation. The results of internal deletion studies of the promoter region suggested that there was also a region responsible for ATF1 oxygen regulation. This region contained the consensus binding sequence for the hypoxic repressor Rox1p. In vitro binding studies showed that Rox1p binds to the region responsible for oxygen regulation. To investigate the effect of the hypoxic repressor complex on transcription, ATF1 expression was measured in rox1, tup1 and ssn6 disruptant strains. It was found that rox1, tup1 and ssn6 disruption caused elevated expression of ATF1 under aerobic conditions. Thus, the activation of ATF1 transcription is dependent on Rap1p, and the Rox1p-Tup1p-Ssn6p hypoxic repressor complex is responsible for repression by oxygen. Furthermore, a study of ATF1 expression in a sch9 null mutant suggested that the Sch9p protein kinase is involved in ATF1 trancriptional activation.

Acetyltransferases↗

PubMed2026

Fluoride as a Modifier of Metallome Homeostasis: A Systematic Review of Animal Studies.

Fluoride is widely used for caries prevention due to its effects on mineralized tissues, yet its potential role as a modifier of systemic metal homeostasis remains insufficiently explored. This systematic review synthesizes preclinical evidence on the association between fluoride exposure and changes in metal and semi-metal concentrations across biological matrices. A comprehensive search strategy was conducted across major databases without language or date restrictions, following SyRF, CAMARADES and PRISMA 2020 guidelines. Thirty-one animal studies were included, encompassing multiple species, exposure conditions and analytical approaches. Despite substantial methodological heterogeneity, consistent patterns emerged. Fluoride exposure was associated with element-specific redistribution of the metallome rather than uniform change. Essential elements were predominantly depleted, most consistently zinc, copper and manganese, whereas the toxic metals lead and cadmium tended to be retained. This contrast between homeostatically regulated essential elements that are lost and non-regulated toxic metals that accumulate supports the hypothesis that fluoride differentially modifies the distribution and retention of co-existing elements. The novelty of this review lies in integrating metallomic outcomes across experimental models, highlighting fluoride as a potential systemic modulator rather than a tissue-specific agent. Although variability in study design and risk of bias limits causal inference, the consistent directionality of findings across models reinforces their biological plausibility and translational relevance.

Animals↗

PubMed2024

Association of urinary levels of trace metals with type 2 diabetes and obesity in postmenopausal women in Korea: A community-based cohort study.

Several toxic metals have been associated with metabolic diseases like obesity and diabetes mellitus (DM) in humans. However, knowledge regarding the influence of many trace elements, especially in combination with essential elements is limited. This study aims to address this research gap by investigating the associations of both non-essential and essential inorganic trace elements in urine with DM and obesity, employing a group of postmenopausal women (n = 851) from the Korean Genome and Epidemiology Study (KoGES) cohort. Urine samples were collected during 2017-2018, and were analyzed for 19 trace elements using inductively coupled plasma-mass spectrometry and an automatic mercury analyzer. Outcomes of interest were metabolic diseases (DM and obesity) and DM-related traits (insulin resistance and β-cell function). After adjustment of covariates, such as age, alcohol consumption, smoking status, educational level, and daily energy intake, urinary Zn, Ni, Tl, and U levels were associated with the prevalence of DM and homeostatic model assessment (HOMA) for insulin resistance (IR) in the postmenopausal women. In the whole mixture model, however, no significant association was observed for the prevalence of DM. Urinary levels of Zn were negatively associated with HOMA of β-cell function (HOMA-β), positively correlated with HbA1c levels, HOMA-IR, and prevalent DM. In addition, urinary Zn, Co, Tl, and Cs were positively associated with obesity (body mass index ≥25 kg/m2). The present observation shows that several individual elements and their mixtures may be associated with the prevalence of DM, IR, or obesity.

Humans↗

PubMed1994

A conserved upstream element is essential for transcription of the Leishmania tarentolae mini-exon gene.

We demonstrate that the mini-exon genes of Leishmania tarentolae are individually transcribed by an enzyme pharmacologically identified as RNA polymerase II. To study transcription in these ancient eukaryotes, a stable transformation assay using an episomal mini-exon gene was developed. The introduced mini-exon gene, which had been marked with a 40 bp tag, yielded the predicted tagged transcript. An upstream cis-acting element that was essential for transcription of the mini-exon gene was identified by site-directed mutagenesis. Block substitution mutagenesis of the -1 to +9 and +10 to +19 regions of the exon results in 20- to 100-fold decreased levels of the tagged transcript in steady-state RNA. However, since these two mutations resulted in only a 2- to 3-fold decrease in nascent RNA levels, steady-state levels appear to be affected greatest by the stability of the resulting transcript. In contrast, mutation of the -67/-58 region resulted in undetectable levels of both steady-state and nascent RNA from the introduced gene. We conclude, therefore, that this upstream element, which is highly conserved in all Leishmania species, is a component of the mini-exon gene promoter.

Animals↗

PubMed1993

[Gynecologic oncology and clinical trials].

Clinical trials have been developed tremendously in oncology because of its clear endpoints. In Japan, however, a concept of clinical trial has not been so accepted for long time. Recently, Minister of Health and Welfare announced guide lines of clinical evaluation of anticancer drug and statistical analysis. Elements essential to design of clinical trials are following; the first element is a clearly stated hypothesis. The hypothesis must be testable, that is, the investigator must have a clear idea of how these differences will be determined in this study subjects. The trial must have a well documented protocol and have a well defined primary endpoint by which the anticipated effect of the new treatment will be evaluated. Although one or two secondary endpoints may also be identified in the trial, the primary endpoint is the major focus of the trial and determines trial design, size, and early stopping rules. The clinical trial must be appropriately designed so that the hypothesis can be adequately tested and evaluated. The study may compare the new therapy to a standard treatment or assess the basic characteristics of the treatment. The clinical trial must be designed so that adequate sensitivity (significance level) and power to provide a high degree of confidence that results are not spurious. The next critical aspect to the performance of a successful clinical trial is the ability to accrue adequate numbers of patients within a reasonable period of time for the study to be completed. The next essential element to the design of a clinical trial is the prospective selection of statistical tool appropriate to the data to be collected.(ABSTRACT TRUNCATED AT 250 WORDS)

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1996

[Role of essential trace elements on sexual function and its disorder].

Recent reports on the role of trace elements in human reproductive potential were summarized. Zn has been known as an important element in male sexual function, and works as key element in several seminal reactions. Se, Fe, and Cu are also essential for male fertility. Intracellular Ca play an important role in many reactions such as sperm motility, acrosome reaction, capacitation, etc. Our data on 13 elements in semen samples from 110 male patients of infertile couples were also described; 1) element concentrations were Na > P, K > Ca > Zn > Mg > Fe > Cu > Se >> Sn, Ni, Co, Cd, 2) Correlation between Se concentration and sperm concentration (r = 0.589, p < 0.001), where Se contents in spermatozoa showed very high correlation (r = 0.886), 3) Zn in semen were not correlated with sperm parameters, but were correlated with concentrations of Mg (r = 0.903), K (r = 0.810), and Ca (r = 0.715). There has been few information on the role of trace elements in female sexual function.

Animals↗

PubMed1999

A strong constitutive positive element is essential for the ammonium-regulated expression of a soybean gene encoding cytosolic glutamine synthetase.

In order to identify important promoter elements controlling the ammonium-regulated expression of the soybean gene GS15 encoding cytosolic glutamine synthetase, a series of 5' promoter deletions were fused to the GUS reporter gene. To allow the detection of positive and negative regulatory elements, a series of 3' deletions were fused to a -90 CaMV 35S promoter fragment placed upstream of the GUS gene. Both types of construct were introduced into Lotus corniculatus plants and soybean roots via Agrobacterium rhizogenes-mediated transformation. Both spectrophotometric enzymatic analysis and histochemical localization of GUS activity in roots, root nodules and shoots of transgenic plants revealed that a strong constitutive positive element (SCPE) of 400 bp, located in the promoter distal region is indispensable for the ammonium-regulated expression of GS15. Interestingly, this SCPE was able to direct constitutive expression in both a legume and non-legume background to a level similar to that driven by the CaMV 35S full-length promoter. In addition, results showed that separate proximal elements, located in the first 727 bp relative to the transcription start site, are essential for root- and root nodule-specific expression. This proximal region contains an AAAGAT and two TATTTAT consensus sequences characteristic of nodulin or nodule-enhanced gene promoters. A putative silencer region containing the same TATTTAT consensus sequence was identified between the SCPE and the organ-specific elements. The presence of positive, negative and organ-specific elements together with the three TATTTAT consensus sequences within the promoter strongly suggest that these multiple promoter fragments act in a cooperative manner, depending on the spatial conformation of the DNA for trans-acting factor accessibility.

Base Sequence↗

PubMed1994

A 20 nucleotide upstream element is essential for the nopaline synthase (nos) promoter activity.

The nopaline synthase (nos) promoter is expressed in a wide range of plant cell types and regulated by various developmental and environmental factors. The nos upstream control region essential for this regulation was studied by means of synthetic oligomers using transient and stable transformation systems. Insertion of a 20 nucleotide sequence containing two hexamer motifs and a spacer region into deletion mutants lacking the upstream control region was essential for promoter activity. Mutation of one or more nucleotides of either hexamer sequence significantly altered the strength of expression of the nos promoter. Point mutations within the spacer region also strongly influenced promoter strength. Insertion of multiple copies of the 20 nucleotide sequence into the nonfunctional deletion mutants proportionally increased the promoter activity. These results suggest that this twenty nucleotide sequence is essential for the nos promoter to function. Substitution of the nos element with the ocs or 35S as-1 which contain similar hexamer motifs restored not only promoter activity but also responses to wounding, auxin, methyl jasmonate, and salicylic acid.

Amino Acid Oxidoreductases↗

PubMed1983

Vigorous supplementation of a hypocaloric diet prevents cardiac arrhythmias and mineral depletion.

We have previously demonstrated that a hypocaloric, nutritionally deficient, liquid protein diet is associated with potentially life-threatening cardiac arrhythmias, which increased in frequency and complexity over the duration of the study. The present investigation was designed to evaluate the metabolic and cardiac changes associated with a hypocaloric, but otherwise nutritionally complete, diet. Six healthy, obese females from 154 to 182 percent of ideal body weight were evaluated in a metabolic ward for 48 days. The subjects ingested a weight maintenance diet during an eight-day period, which was followed by 40 days of an experimental diet containing 472 kcal of a mixture of protein (60 percent of calories), carbohydrate (25 percent), and fat (15 percent). This diet equaled or exceeded the recommended daily allowances for minerals, trace elements, vitamins, and essential fatty acids. The subjects were monitored for balances of nitrogen and minerals, as well as for the appearance of cardiac arrhythmias by 24-hour electrocardiographic recordings. Nitrogen balance was positive, and the previously demonstrated negative balances for potassium, sodium, calcium, magnesium, and phosphorus were either reversed or markedly decreased. In contrast to our previous study, no arrhythmias were observed in subjects ingesting the present experimental diet, and no significant change in cardiac rhythm was found in 13 obese, but otherwise healthy, outpatients. The data, based on a limited number of subjects, suggest that a hypocaloric diet vigorously supplemented with essential elements, micronutrients, and vitamins appears to be safer than the once popular, incomplete liquid protein preparation.

Adult↗

PubMed1999

Closing the loop: optimizing physicians' operational and strategic behavior.

Clinical databases are essential elements in optimizing medical care. They are no finality by themselves, but essential elements in the generation of knowledge. Optimal medical care starts with optimal care based on existing knowledge. This care continues with the registration of the variability in morbidity, comorbidity, and therapy, but also the registration of the early and late outcome. This should then allow the generation of structured inferences based on this registration and the closure of the loop, by treating patients according to this newly created evidence.

Belgium↗

PubMedDate not supplied

Shaping the advanced practice psychiatric-mental health nursing role: a futuristic model.

As advanced practice psychiatric-mental health nursing has transitioned from earlier models of practice, elements of clinical specialist and psychiatric nurse practitioner roles are being blended to produce a new type of practitioner. The challenge of preserving mental health expertise while expanding advanced practice primary and primary mental health care competencies is addressed in several nursing education models. At New York University's Division of Nursing, faculty have designed a program around elements identified as essential to the autonomy demanded of the evolving role, knowledge, and skills basic to broad based health care and mental health care delivery with quality patient care outcomes and the competencies necessary for accountability as care providers in a changing health care delivery system. Essential elements, resources to identify them, and strategies to attain them are discussed. Approaches that promote student, clinician, and faculty development and maximize education affirm the specialty's capacity for innovation and the profession's capacity for new direction and futuristic change.

Curriculum↗

PubMed1998

Differentiation-stimulated activity binds an ETS-like, essential regulatory element in the human promyelocytic defensin-1 promoter.

The human HNP-defensin-1 gene encodes a peptide antibiotic found exclusively in neutrophils and is key to elimination of microbes. Expression is a marker for the granulocytic lineage and for certain stages of differentiation and is not known to be inducible in mature cells under physiological conditions. Low level of transcription also occurs in HL-60 promyelocytic leukemia cells and is greatly activated upon drug-induced granulocytic maturation and by low doses of retinoic acid, in a strictly cell-specific manner (Herwig, S., Su, Q., Ma, Y., and Tempst, P. (1996) Blood 87, 350-364). We have analyzed a 10-kilobase pair region, upstream of the defensin-1 cap site, for the presence of control elements, and we describe a minimal promoter (position -83 to +82) required to drive transcription in HL-60 cells in a quasi cell-specific manner. Our data also suggest the presence of negative regulatory elements in the -416/-191 region that may further contribute to cell specificity in a chromosomal context. The basal promoter contains two functionally essential, ETS-like (GGAA core sequence) elements. The proximal site (-22/-19) constitutively binds the PU.1 transcription factor in vitro and could function, together perhaps with an adjacent TA-rich sequence (-32/-25), in assembly of a myeloid-restricted, basal transcription factor complex. The distal site (-62/-59) interacts in vitro with an unidentified activity, distinct from PU.1, ETS-1, PEA3, and ELK-1 (factors with definite binding site similarities), and is greatly stimulated by phosphorylation during granulocytic differentiation of HL-60 cells. Identification of this protein will be important to resolve the molecular mechanisms controlling temporal, granulocytic restricted gene expression.

Amino Acid Sequence↗

PubMed1989

Identification of a promoter region for 3.6-kilobase mRNA of hepatitis B virus and specific cellular binding protein.

The promoter region for transcription of the 3.6-kilobase mRNA of hepatitis B virus was identified by the chloramphenicol acetyltransferase assay by using HuH-7 hepatoma cells and was found to function directly in virus production by way of the transient expression system of HBV. The 5'-upstream sequence from nucleotides 1573 to 1657 (the transcription start site) was indispensable for promoter function, while the AT-rich sequence (from nucleotides 1581 to 1604) containing a directly repeated sequence TGTT connecting the same flanking sequence PyAAAGAC (where Py is a pyrimidine) at both sides was an essential element within this promoter region. A specific cellular factor which interacted with the essential element was detected in the HuH-7 cell extract. A similar binding factor was also observed in HepG2 and huH2-2 hepatoma cells. This factor may thus be responsible for regulating 3.6-kilobase mRNA, pregenome RNA transcription, or both.

Base Sequence↗

PubMed1998

Streamlining outpatient geriatric assessment: essential social, environmental and economic variables.

There are no known standardized instruments that encompass all of the essential elements of a streamlined outpatient geriatric assessment. A process of arriving at a consensus on essential elements of streamlined geriatric assessment in 3 domains was initiated and described. Two rounds of the Delphi technique were conducted to identify social, environmental and economic variables essential for such an assessment. Consensus among an expert panel was achieved and a list of 27 variables was reduced to 16. This result is discussed in terms of assessment context and standardizing assessment, using case examples.

Aged↗

PubMed1995

Essential and toxic element concentrations in fresh and formalin-fixed human autopsy tissues.

The concentrations of five essential elements and six potentially toxic elements were determined in seven organs collected at autopsy from 30 human subjects. Elemental analyses were carried out by graphite furnace atomic absorption spectroscopy, and inductively coupled plasma emission spectroscopy, and inductively coupled plasma mass spectroscopy, and concentrations in fresh and formalin-fixed tissues were compared. Formalin-fixation long-term storage has little effect on most element concentrations in tissue, except for Al and Mn, which changed with prolonged storage in formalin. The kidney and liver contained the greatest concentrations of toxic elements compared with other organs, whereas the essential elements were uniformly distributed among all organs. There was no more than a 10-fold difference in the tissue concentration of the elements studied among the organs, except for the concentration of Fe in liver, and Ca and Mg in bone. We also demonstrate that these elements are homogeneously distributed in tissues.

Aluminum↗

PubMedDate not supplied

Collaborative practice: myth or reality?

In response to demands of internal constituencies and pressures from external forces, many healthcare institutions have been experimenting with collaborative practice, wherein professionals function interdependently in patient-centered healthcare. In this article, the authors move beyond philosophical constructs and focus on the essential elements of this important innovation. Making collaborative practice a reality in institutions requires an understanding of the essential elements, persistent and continuing efforts, and rigorous evaluation of outcomes. Satisfaction, quality, and cost effectiveness are essential factors on two dimensions: outcomes for patient care providers; and outcomes for patients. Ultimately, collaborative practice can be recognized by demonstrated effective communication patterns, achievement of enhanced patient care outcomes, and efficient and effective support services in place. If these criteria are not met, collaborative practice is a myth and not a reality in your institution.

Hospitals↗

PubMed1993

Molybdenum: an essential trace element.

Molybdenum is found in most foods, with legumes, dairy products, and meats being the richest sources. This metal is considered essential because it is part of a complex called molybdenum cofactor that is required for the three mammalian enzymes xanthine oxidase (XO), aldehyde oxidase (AO), and sulfite oxidase (SO). XO participates in the metabolism of purines, AO catalyzes the conversion of aldehydes to acids, and SO is involved in the metabolism of sulfur-containing amino acids. Molybdenum deficiency is not found in free-living humans, but deficiency is reported in a patient receiving prolonged total parenteral nutrition with clinical signs characterized by tachycardia, headache, mental disturbances, and coma. The biochemical abnormalities in this acquired molybdenum deficiency include very low levels of uric acid in serum and urine (low XO activity) and low inorganic sulfate levels in urine (low SO activity). Inborn errors of isolated deficiencies of XO, SO, and molybdenum cofactor are described. Although XO deficiency is relatively benign, patients with isolated deficiencies of SO or molybdenum cofactor exhibit mental retardation, neurologic problems, and ocular lens dislocation. These abnormalities seem to be caused by the toxicity of sulfite and/or inadequate amounts of inorganic sulfate available for the formation of sulfated compounds present in the brain. XO and AO may also participate in the inactivation of some toxic substances, inasmuch as studies suggest that molybdenum deficiency is a factor in the higher incidence of esophageal cancer in populations consuming food grown in molybdenum-poor soil.

Deficiency Diseases↗