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S Sharp

Publications and source records attributed to S Sharp.

70 records · Page 4Linked to original sources
PubMed1983

Holoprosencephaly in infants of diabetic mothers.

We report seven infants of diabetic mothers, affected with holoprosencephaly malformation sequence. An additional 15 cases assembled from personal communications and the literature indicate that holoprosencephaly, like neural tube, cardiac, and caudal defects, is specifically increased in children of diabetic mothers. Incidence figures from newborn surveys demonstrate a risk for holoprosencephaly in infants of diabetic mothers comparable to the 1% risk for caudal regression malformation sequence. The embryologic timing of cranial, cardiac, and caudal defects emphasizes the need for pregnancy planning and diabetes control.

Abnormalities, Multiple↗
PubMed1983

Human monocytes, B lymphocytes, and non-B lymphocytes each have structurally unique Fc gamma receptors.

Human Fc gamma-binding macromolecules were isolated from subpopulations of mononuclear cells by repetitive affinity chromatography. Mononuclear cells, nylon wool-filtered cells, plastic-nonadherent cells, and plastic-adherent cells from normal donors were radiolabeled by using 125I and lactoperoxidase. Washed cells were solubilized in 1% NP-40 buffer containing proteinase inhibitors at 0 degrees C. Fc gamma receptors were purified on human IgG-Sepharose columns by use of the repetitive affinity chromatography procedure. Analysis by SDS-polyacrylamide gel electrophoresis demonstrated only a 52,000 to 58,000 Mr Fc gamma receptor from nonadherent cell populations. Both rosetting and nonrosetting subpopulations of non-B lymphocytes expressed the 52,000 to 58,000 Mr receptor. The predominant Fc gamma receptor isolated from plastic-adherent cells was a 60,000 to 68,000 Mr macromolecule. Cell preparations enriched in B lymphocytes yielded prominent 43,000 Mr Fc gamma receptors. Thus human monocytes, B lymphocytes, and non-B lymphocytes each appear to have structurally distinct and unique Fc gamma receptors.

Chemical Phenomena↗
PubMed1982

The 5- flanking sequences of Drosophila tRNAArg genes control their in vitro transcription in a Drosophila cell extract.

The transcription efficiencies of four Drosophila tRNAArg genes located in a tRNA gene cluster at region 42A on chromosome 2, and containing identical coding sequences, were studied in Drosophila Kc cell extracts. Transcription is modulated by the 5' flanking sequences; efficient transcription is dependent on the presence of an optimal 5' flanking sequence. One of the genes, p17D Arg, is not transcribed in the homologous extract but does compete with the other genes for transcription factors. Deletion of a specific sequence from the 5' flank of the gene of p17D Arg leads to an increase in transcription efficiency. All tRNAArg genes are efficiently transcribed in extracts from HeLa cells. However, introduction of small amounts of Drosophila extract reduces the efficiency of transcription in HeLa extracts. This is due to incompatibility between transcriptional components of the two extracts.

Animals↗
PubMed1982

The minimum intragenic sequences required for promotion of eukaryotic tRNA gene transcription.

Transcription of eukaryotic tRNA genes is controlled by two intragenic regions, the D-control region (which in the tRNA codes for the D-stem and -loop) and the T-control region (which in the tRNA codes for the T psi C loop). To determine whether these sequences alone are sufficient to promote tRNA gene transcription in vitro, the two control regions of a Drosophila tRNAArg gene were cloned separately from the context of the parental DNA (these constructions are called tRNA minigenes). The tRNA minigene that contains both intragenic control regions supports in vitro RNA synthesis in Xenopus laevis oocyte and HeLa cell transcription systems. The mutant which has deletions to nucleotide 7 within the mature tRNA coding region, pArg5.7, and minigenes derived from it do not support RNA synthesis in a Drosophila Kc cell transcription system. Xenopus and Hela extracts transcribe pArg5.7 albeit at reduced levels compared to the wild-type gene. The tRNA minigene that contained only the D-control region was not able to support RNA synthesis in any of these three transcription systems. A mutant tRNA gene comprising the 3' half of the tRNAArg gene similarly was not able to support RNA synthesis. These experiments show that the DNA sequence from nucleotides 7-58, which contains both intragenic control regions of the tRNA gene, possesses sufficient information to initiate specific transcription by RNA polymerase III in Xenopus and HeLa systems. The transcription efficiency of this tRNA minigene however is reduced to about 20% the transcription level of the wild type tRNA gene. This lowered level of transcriptional efficiency results from deleting the ends of the native tRNA gene and its adjacent flanking sequences. The affects of deleting 5' sequences are most pronounced in the Drosophila transcription system.

Animals↗
PubMed1982

The 5S RNA genes of Schizosaccharomyces pombe.

The genomic arrangement and sequences of S. pombe 5S RNA genes are reported here. The 5S gene sequences appear to be dispersed within the genome, and are found independently of other rRNA genes. The sequences of two 5S genes examined show identical coding regions of 119 base pairs but have widely varying flanking sequences. A tRNAAsp gene is found in the 3' flanking region of one of the 5S genes. The tRNAAsp gene is faithfully transcribed in an X. laevis in vitro system, while the 5S genes are not transcribed in this system. The phylogenetic position of S. pombe is examined through comparison of 5S RNA sequences.

Animals↗
PubMed1982

Eukaryotic tRNA gene transcription is controlled by signals within and outside the mature coding sequence.

We have identified the region within a eukaryotic tRNA gene required for initiation of transcription. These results were obtained by systematically constructing deletions extending from the 5'- or the 3'-flanking regions into a cloned Drosophila tRNAArg gene using nuclease BAL-31. Two control regions within the coding sequence were identified. The first was essential for transcription and was contained between nucleotides 8 to 25 of the mature tRNA sequence. Genes devoid of the second control region, which was contained between nucleotides 50 to 58 of the mature tRNA sequence, could be transcribed but with reduced efficiency. Thus, the promoter regions within a tRNA gene encode the tRNA sequences of the D-stem and D-loop, the invariant U at position 8, and the semi-invariant GTpsi C sequence. While transcription of Drosophila tRNA genes is controlled by signals within the mature tRNA coding region deletion analysis has revealed an oligonucleotide sequence in the 5'-flanking region of a Drosophila tRNA2Lys gene to be responsible for the poor transcriptional activity of this and of other tRNA genes. The oligonucleotide responsible for transcriptional repression is GGCAGTTTTTG and is located 13 nucleotides upstream from the mature tRNA coding sequence. Since the sequence of the undecanucleotide is well conserved within the 5'-flanking region of Drosophila tRNA2Lys genes an investigation of why the transcription of all these genes is not similarly repressed revealed that the position of this oligonucleotide, relative to the mature coding sequence, influences the extent of transcriptional repression.

Animals↗
PubMed1981

Identification of regulatory sequences contained in the 5'-flanking region of Drosophila lysine tRNA2 genes.

Transcription of Drosophila tRNA genes is controlled by signals within and outside the region coding for the mature tRNA. Deletion analysis has revealed an oligonucleotide sequence in the 5'-flanking region of a Drosophila tRNA2Lys gene to be responsible for the poor transcriptional activity of this and of other tRNA genes. The low template activity of this gene was maintained even after deletion of the 5'-flanking region up to nucleotide -23. Removal of nine additional nucleotides resulted in complete loss of transcriptional repression. The oligonucleotide responsible for transcriptional repression is GGCAGTTTTTG and is located 13 nucleotides upstream from the mature tRNA coding sequence. Since the sequence of the undecanucleotide is well conserved within the 5'-flanking region of all known Drosophila tRNA2Lys genes, we have investigated why the transcription of all these genes is not similarly repressed. Deletion or insertion of nucleotides between the mature tRNA coding region and this oligonucleotide resulted in tRNA genes with increased template activity. This observation suggests that the position of this oligonucleotide relative to some element downstream influences the extent of transcriptional repression.

Animals↗
PubMed1981

The initiator tRNA genes of Drosophila melanogaster: evidence for a tRNA pseudogene.

We have isolated four segments of Drosophila melanogaster DNA that hybridize to homologous initiator tRNAMet. Three of the cloned fragments contain initiator tRNA genes, each of which can be transcribed in vitro. The fourth clone, pPW568, contains an initiator tRNA pseudogene which is not transcribed in vitro by RNA polymerase III. The pseudogene is contained in a 1.15 kb DNA fragment. This fragment has the characteristics of dispersed repetitive DNA and hybridizes in situ to at least 30 sites in the Drosophila genome. The arrangement of the initiator tRNA genes we have isolated, is different to that of other Drosophila tRNA gene families. The initiator tRNA genes are not clustered nor intermingled with other tRNA genes. They occur as single copies within an approximately 415-bp repeat segment, which is separated from other initiator tRNA genes by a mean distance of 17 kb. In situ hybridization to polytene chromosomes localizes these genes to the 61D region of the Drosophila genome. Hybridization analysis of genomic DNA indicates the presence of 8-9 non-allelic initiator tRNA genes in Drosophila melanogaster.

Animals↗
PubMed1981

Internal control regions for transcription of eukaryotic tRNA genes.

We have identified the region within a eukaryotic tRNA gene required for initiation of transcription. These results were obtained by systematically constructing deletions extending from the 5' or the 3' flanking regions into a cloned Drosophila tRNAArg gene by using nuclease BAL 31. The ability of the newly generated deletion clones to direct the in vitro synthesis of tRNA precursors was measured in transcription systems from Xenopus laevis oocytes, Drosophila Kc cells, and HeLa cells. Two control regions within the coding sequence were identified. The first was essential for transcription and was contained between nucleotides 8 and 25 of the mature tRNA sequence. Genes devoid of the second control region, which was contained between nucleotides 50 and 58 of the mature tRNA sequence, could be transcribed but with reduced efficiency. Thus, the promoter regions within a tRNA gene encode the tRNA sequences of the D stem and D loop, the invariant uridine at position 8, and the semi-invariant G-T-psi-C sequence.

Animals↗
PubMedDate not supplied

Blood glucose monitoring in the intensive care unit.

Patients in intensive care units may have high blood glucose levels for a variety of reasons. Careful control of blood glucose has a number of advantages. Nurses need to be trained in the use of blood glucose meters to obtain accurate results.

Blood Glucose↗
PubMedDate not supplied

Understanding stress in the ICU setting.

This article discusses the physiological effects of stress on patients, relatives and staff in the intensive care unit (ICU). It examines the short- and long-term effects of cortisol on various systems in the body. The information contained in this article encompasses the recognition and understanding of the general adaptation syndrome as described by Seyle (1975). Many nurses working in ICU may identify with the symptoms and subsequent physiological and psychological responses to stress and thus enable informed discussion when planning the care of their patients or support of the relatives, colleagues and themselves.

Autonomic Nervous System↗
PubMedDate not supplied

[The Clock Test: drawing a clock for detection of cognitive disorders in geriatric patients].

Patients of a geriatric hospital (n = 263; 145 women, 118 men) had the task of drawing a clock and indicating a given time by the placements of hands. Errors were classified hierarchically by using a five-category-panel based on defined criteria. Its use as a "first-line" screening test for cognitive disorders in old age was evaluated. Retest- (r = 0.89) and interrater- correlations (r = 0.81) were satisfying. The results of this "clock drawing test" were compared both to the outcome in the Abbreviated Mental Test (AMT) and to the general judgment of the patients' cognitive status, based on the history, the report of informants, on clinical observation and examination. Patients with faultless clock drawings performed well in the AMT. However, prediction of the outcome in the AMT gradually became impossible with poorer performance in the clock drawing test, resulting in a low specificity (0.74) for a normal AMT. Specificity of the clock drawing test increased (0.79) for the general judgment of cognitive disorder, with sensitivity remaining constant (0.84). Sudden onset of cognitive disorder (most commonly confusion) in case of acute disease was discovered by the clock drawing test. Focusing on all patients without apparent cognitive disorder and with normal AMT-result, the subgroup of patients with faultless clock drawings was significantly younger (t = 5.0); p < 0.001). It is suggested to use the clock drawing test in addition to conventional psychometric screening tests because it requires visuospatial skills and conceptual thinking in addition to mere mnestic and verbal qualities.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗