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Biomedical subjects

M R Roberts

Publications and source records attributed to M R Roberts.

32 records · Page 2Linked to original sources
PubMed1995

Status epilepticus in children.

The emergency physician caring for children should have a thorough understanding of all aspects of SE. The morbidity and mortality attributable to this condition can be minimized through rapid recognition of the disorder, a rational therapeutic and diagnostic plan, and recognition and management of typical complications. Promising developments include new drugs, such as the phenytoin prodrug and the use of newer dosing methods and routes of administration for current drugs, such as very high-dose phenobarbital, thiopental barbiturate coma, and continuously infused midazolam.

Anticonvulsants↗
PubMed1994

Targeting of human immunodeficiency virus-infected cells by CD8+ T lymphocytes armed with universal T-cell receptors.

We have developed an immunotherapeutic approach with potential application in the treatment of viral and malignant disease. We show that primary CD8+ T cells isolated from peripheral blood can be genetically modified by retroviral transduction to express high levels of universal (major histocompatibility complex-unrestricted) chimeric T-cell receptors specific for human immunodeficiency virus (HIV) antigens. Two classes of HIV-specific URs in which the antigen-binding domain is comprised of either CD4 or a single-chain antibody are capable of activating a number of T-cell effector functions in response to target cells, including cytolysis, in a highly sensitive and specific manner. Importantly, we have addressed a number of issues which, although particularly relevant to the clinical application of this approach in the treatment of HIV infection, may also impact on the potential of UR immunotherapy for other disease targets. The UR immunotherapeutic system is particularly suited for evaluation in the clinical setting.

Animals↗
PubMed1994

A DNA-binding activity, TRAC, specific for the TRA element of the transferrin receptor gene copurifies with the Ku autoantigen.

We have previously described purification and characterization of a nuclear protein, TREF, which interacts specifically with the transcriptional control element, TRA, of the human transferrin receptor (TR) gene. In this report we show that TREF can be separated into two functionally distinct DNA-binding activities. The first DNA-binding activity (TRAC) is highly specific for the 8-bp element TRA and the related Escherichia coli cAMP receptor binding site. This motif is homologous to the phorbol 12-tetradecanoate 13-acetate- and cAMP-responsive elements of eukaryotic genes and the regulatory proximal sequence elements of the U1 small nuclear RNA gene and is also present in the promoter of the Drosophila melanogaster yolk protein factor 1 gene. In striking contrast, the second activity exhibits high affinity for the ends of double-stranded DNA in a sequence-unspecific manner and is attributable to the heterodimeric Ku autoantigen. Notably, transcription of Ku is induced during mid-late G0/G1 with kinetics similar to the TR gene. Ku is a highly abundant nuclear protein possessing nonspecific affinity for the ends of DNA, whose biological role remains to be elucidated. A transcriptional role for this protein has been proposed, however, on the basis of studies attributing DNA sequence-specific binding activity, notably for TRA-like sequences described above, directly to the Ku heterodimer. The observation that Ku-mediated nonspecific DNA-binding activity copurifies with the TRA-specific activity, TRAC, clearly has implications for these and related studies. The unusual properties of TRAC activity and its relationship, if any, with the enigmatic Ku protein, are discussed.

Antigens, Nuclear↗
PubMed1994

kat: a high-efficiency retroviral transduction system for primary human T lymphocytes.

We describe a novel retroviral packaging system in which high titer amphotropic retrovirus was produced without the need to generate stable producer clones. kat expression vectors, which produce high levels of retroviral vector transcripts and retroviral packaging functions, were transfected into 293 cells followed by virus harvest 48 hours posttransfection. Viral titers as high as 3.8 proviral copies/cell/mL of frozen supernatant in 3T3 cells were obtained, 10- to 50-fold greater than transient viral titers reported using 3T3-based retroviral packaging lines. Cocultivation of primary human CD8+ T lymphocytes after transient transfection of 293 cells with kat plasmids resulted in transduction efficiencies of 10% to 40%, 5- to 10-fold greater compared to cocultivation with a high titer PA317 producer clone and significantly greater than previously reported results for transduction of primary human T lymphocytes with retroviral vectors. Virus produced using the kat system was shown to be free of detectable replication competent retrovirus by an extended provirus mobilization assay, demonstrating that this system is as safe as currently available stable packaging lines. The kat virus production system should be of general use for the rapid production of high titer viral supernatants, as well as for high-efficiency transduction hematopoietic cell types refractory to retroviral transduction.

3T3 Cells↗
PubMed1993

Characterization of a new class of oleosins suggests a male gametophyte-specific lipid storage pathway.

The expression and sequences of two related antherspecific cDNAs (I3 and C98) of Brassica napus (oilseed rape) were examined. These cDNAs were found to exhibit significant predicted amino acid sequence similarity with a group of seed-specific proteins, the oleosins, which are involved in oil body membrane structure. Pollen of B. napus also contains oil bodies, and the synthesis and accumulation of these organelles correlates with expression of the I3 and C98 transcripts. The protein content of purified pollen oil bodies was therefore examined in order to determine the presence or absence of possible oleosins. One major protein species of 14 kDa was identified and subjected to N-terminal amino acid sequence determination. The sequence of this pollen oil body associated protein is homologous to the predicted sequence of one of the anther-specific cDNs, I3, implying that this cDNA represents an anther-specific oleosin gene expressed in developing pollen. The expression of other genes active during seed oil body formation was also examined, and these were found to be specific to the sporophyte, inferring the existence of specific components of the pathway of lipid synthesis and storage in the male gametophyte. These possibilities and the relationship between different oleosin genes are discussed.

Amino Acid Sequence↗
PubMed1993

Gametophytic and sporophytic expression of an anther-specific Arabidopsis thaliana gene.

Genomic and cDNA clones of the anther-specific APG gene from Arabidopsis thaliana and Brassica napus, which encodes a novel proline-rich protein, were isolated and characterized. Southern blotting and Northern analysis of male fertile and cytoplasmic male sterile varieties of B. napus showed that the APG gene is present as a single copy in the Arabidopsis genome, and that the B. napus APG gene is a member of a small anther-specific gene family. Analysis of developmentally staged B. napus flower buds indicated that APG transcript is confined to the anther during the period of microspore development. Reporter gene fusions established that the APG promoter directs expression in a number of cell types in anthers of transformed plants. This expression is consistent with the temporal pattern of mRNA accumulation in B. napus buds and follows a complex developmental pattern. Most significantly, the promoter is active in both sporophytic and gametophytic cell types, with activity of the transgene in each cell type being delineated by various cytological markers.

Amino Acid Sequence↗
PubMed1991

A Brassica napus mRNA expressed specifically in developing microspores.

The I3 cDNA isolated from a library made from 2-4 mm (immature) anthers of Brassica napus shows microspore-specific expression. Homologous transcripts are detected in buds and anthers of male-fertile plants, but not in green tissues, roots, or in cytoplasmic male-sterile buds. High expression of the transcript is limited to microspores entering and undergoing mitosis. The predicted peptide sequence of the cDNA shows an unusual repeated alanine/proline motif at the C-terminus, which may be of importance in the native protein structure.

Amino Acid Sequence↗
PubMed1991

Evaluation of behavioral and cognitive changes: the mental status examination.

Patients who present to the Emergency Department with a behavioral or cognitive disorder should be treated in an organized fashion. The most important element of their care is determining the etiology of their abnormality, whether organic or functional. The history and physical examination, along with laboratory and ancillary testing, should be directed toward this objective. The mental status examination plays a critical role in establishing the diagnosis. It must be focused and brief. By focusing on seven major areas (affect, attention, language, orientation, memory, visual-spatial ability, and conceptualization), a quick and thorough examination of the patient's mental status can be performed.

Behavior↗
PubMed1990

Binding of nuclear factors to the 5'-interferon consensus sequence of the HLA-A2 class I gene.

To investigate the regulatory role of the conserved interferon consensus sequence (ICS) found in the 5' flanking region of HLA class I genes, we studied the binding of nuclear proteins to the ICS of HLA-A2 gene (ICS-A2) by the gel shift assay. Nuclear extracts from several human cell lines expressing different levels of surface class I molecules reveal an ICS-A2-protein complex of similar mobility, the amount of which varies in a cell type-dependent manner. In some cell lines, interferon-gamma treatment decreased the level of this complex. The overlapping enhancer A element also competes for the formation of this ICS-A2-protein complex. Footprinting and methylation interference analyses demonstrate that nuclear protein(s) protect specific sequences within the ICS-A2 element, suggesting that these protein(s) may represent interferon-sensitive transcription factors.

Base Sequence↗
PubMed1989

Nuclear proteins TREF1 and TREF2 bind to the transcriptional control element of the transferrin receptor gene and appear to be associated as a heterodimer.

Two novel proteins that bind specifically to the transferrin receptor (TR) promoter, have been isolated from HeLa cell nuclear extract using a combination of ion exchange and oligonucleotide-affinity chromatography. TREF1 and TREF2, which have apparent molecular weights of 82 and 62 kDa, respectively, appear to be associated as a heterocomplex (TREF), and both proteins are able to contact target DNA directly. TREF interacts specifically with a region of the TR promoter which contains the TR transcriptional control element. This region is similar in sequence to the cAMP-responsive and phorbol ester-responsive elements found in several viral and cellular genes. Binding of TREF to the TR promoter results in modification of DNA topology over multiple helical turns, including a sequence revealed by a helical periodicity map as having an unusual structure.

Base Sequence↗
PubMed1982

Diagnosis of ruptured ectopic pregnancy with peritoneal lavage.

A case of ruptured ectopic pregnancy with a nondiagnostic culdocentesis is presented. Diagnosis was made by using open diagnostic peritoneal lavage. The patient underwent laparotomy, left salpingectomy, and cornual resection, and had no postoperative complications. In selected patients with suspected ectopic pregnancy, peritoneal lavage may serve as a helpful diagnostic procedure.

Adult↗
PubMedDate not supplied

Exercise effects on withdrawal and mood among women attempting smoking cessation.

This study investigated both acute and longer term ("chronic") effects of vigorous exercise training on affect, nicotine withdrawal, and cigarette craving among women enrolled in a smoking cessation research study. All subjects participated in a 12-week cognitive behavioral smoking cessation program and were randomly assigned to attend three sessions per week of either a vigorous exercise program or contact control. Measures of positive and negative affect, cigarette craving, and nicotine withdrawal were administered immediately before, and again immediately after the final exercise or contact session each week of the program. Study I enrolled 24 women who had been assigned to the exercise condition. Significant reductions in negative affect, nicotine withdrawal and cigarette craving were observed following exercise most weeks of the program. No significant changes in positive affect were observed. In Study II this protocol was repeated among 62 women (44 exercise, 18 contact control) in two consecutive cohorts of the larger study. Significant reduction were observed in negative affect, nicotine withdrawal and cigarette craving during most weeks of the program among exercise subjects but not contact condition subjects. No chronic (baseline to posttreatment) changes in positive or negative affect, cigarette craving or withdrawal symptoms were observed in either study. Vigorous exercise appears to produce acute improvements in withdrawal symptoms, cigarette craving, and negative affect among sedentary women attempting to quit smoking.

Adult↗