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Biomedical subjects

J Norris

Publications and source records attributed to J Norris.

At least 55 records · Page 3Linked to original sources
PubMed1995

Identification of a new subclass of Alu DNA repeats which can function as estrogen receptor-dependent transcriptional enhancers.

We have utilized a genetic selection system in yeast to identify novel estrogen-responsive genes within the human genome and to define the sequences in the BRCA-1 gene responsible for its estrogen responsiveness. This approach led to the identification of a new subclass within the Alu family of DNA repeats which have diverged from known Alu sequences and have acquired the ability to function as estrogen receptor-dependent enhancers. Importantly, these new elements confer receptor-dependent estrogen responsiveness to a heterologous promoter when assayed in mammalian cells. This transcriptional activity can be attenuated by the addition of either of three different classes of estrogen receptor antagonists, indicating that these elements function as classical estrogen receptor-dependent enhancers. Furthermore, this enhancer activity is restricted to a specific subset of DNA repeats because consensus Alu elements of four major subfamilies do not respond to the estrogen receptor. Previously, most Alu sequences have been considered to be functionally inert. However, this work provides strong evidence that a significant subset can confer estrogen responsiveness upon a promoter within which they are located. Clearly, Alu sequences must now be considered as important contributors to the regulation of gene transcription in estrogen receptor-containing cells.

Animals↗
PubMed1995

Invasive rhinosino-orbital aspergillosis with precipitous visual loss.

OBJECTIVE: To describe the clinicopathological and radiologic features in five cases of primary and secondary orbital aspergillosis. DESIGN: Case series. SETTING: Ophthalmology department of a university hospital. PATIENTS: Five patients over 65 years of age with invasive rhinosino-orbital aspergillosis. RESULTS: Presenting features were abrupt onset of proptosis, ophthalmoplegia and blepharoptosis with precipitous visual loss. All had debilitating periorbital pain or headache, but none had orbital inflammatory signs or appeared "toxic." Predisposing causes included alcoholism, low-dose prednisone therapy and insulin-dependent diabetes mellitus. One patient, suspected of having mucormycosis based on tissue biopsy and results of potassium hydroxide preparations, harboured Aspergillus fumigatus, which grew on culture. Secondary bacterial infections developed in three patients. Three patients died from their disease despite aggressive surgical treatment, including exenteration and sinus extirpation. The one patient with primary orbital aspergillosis survived after exenteration. CONCLUSIONS: Sinonasal aspergillosis with orbital extension and primary orbital aspergillosis have a precipitous clinical course that mimics that of mucormycosis and may be fatal despite early exenteration. Computed tomography and magnetic resonance imaging of the sinuses, orbit and head provide complementary diagnostic signs. While results of potassium hydroxide preparations and tissue biopsy guide treatment of fungal infection, definitive diagnosis requires fungal culture. Relatively good vision may be associated with massive orbital and secondary intracranial extension.

Aged↗
PubMed1994

Glycosyl-phosphatidylinositol anchor synthesis in paroxysmal nocturnal hemoglobinuria: partial or complete defect in an early step.

The defect in the biosynthesis of the glycosyl-phosphatidyl inositol (GPI) anchor in paroxysmal nocturnal hemoglobinuria (PNH) appears to be in the initial steps. In biosynthetic studies using [3H]mannose, abnormal granulocytes of eight patients, and B lymphocytes transformed by Epstein-Barr virus of six different patients synthesized dolichyl phosphoryl mannose, but little or no later mannosylated intermediates. When fused with murine cell lines known to be deficient at different biosynthetic steps of the GPI anchor, the GPI-anchor-deficient granulocytes of 21/21 patients and lymphocytes from 6/6 patients complemented all murine cell lines except those of class A; cells of this class are not able to add N-acetylglucosamine to phosphatidylinositol. These studies indicate that the defect in GPI-anchor synthesis in PNH is early in the pathway, and is the same as that of class A mutants, but may be partial in some patients, resulting in the production of small amounts of mannosylated intermediates.

Antigens, CD↗
PubMed1994

Informatics issues for nursing's future.

Automated clinical databases are crucial to the future of nursing but presently are not meeting the needs of clinicians, administrators, educators, or researchers. This article examines theoretical, empirical, and practical issues relating to the development of automated nursing clinical databases that will foster safe, effective practice and further nursing's knowledgebase. A series of key questions are identified relevant to each issue. These issues must be resolved if nurses are to take full advantage of the possibilities inherent in the evolving information technology.

Costs and Cost Analysis↗
PubMed1993

Convulsive threshold differences in right unilateral and bilateral ECT.

UNLABELLED: This study examines how the convulsive threshold in electroconvulsive therapy (ECT) varies with electrode placement (bilateral [BL] versus right unilateral [RUL]), age, gender, weight, and the nasion-inion measurements of the head. METHOD: Twenty-eight subjects underwent stimulus dose titration to determine the convulsive threshold. Titration was accomplished for each subject with both electrode placements during the first and second ECT in a balanced design. Head measurements were made prior to the first ECT. Results indicated that the convulsive threshold was higher for BL than RUL, higher for men than women, increased with age, and increased with an increasing nasion-inion measurement in women but not in men. We concluded that the convulsive threshold varies according to the choice of electrode placement, gender, and age as has been reported by others. We additionally report that the convulsive threshold increases with increasing head size as reflected in the nasion-inion distance.

Adult↗
PubMed1993

Alcohol and violent pornography: responses to permissive and nonpermissive cues.

Both alcohol consumption and violent pornography have been implicated independently in the commission of sexual aggression. In addition to alcohol consumption, the presence of alcohol in the context of violent pornography may act as a permissive cue to influence judgments of such material's acceptability and self-reported likelihood of engaging in sexually violent behavior. To test this proposition, an experiment which varied beverage condition (alcohol vs no alcohol), expectancy set (expect vs do not expect alcohol) and a permissive (presence of alcohol) vs nonpermissive (absence of alcohol) cue was conducted on both male and female subjects. Secondary analyses on male subjects alone investigated the role of the personality trait hypermasculinity in affecting judgments. Results showed that (1) alcohol itself rather than expectancy set influenced judgments and willingness to engage in sexual violence; (2) the presence of alcohol interacted with alcohol consumption to affect willingness to engage in sexual violence; (3) men high in hypermasculinity judged the violent pornographic story more positively than did men low in this trait; and (4) alcohol interacted with hypermasculinity to affect acceptability judgments, but only for men low on this trait. These findings are consistent with cognitive disruption models and show promise for future investigations of the influence of permissive cues, as well as the role of hypermasculinity.

Adult↗
PubMed1993

A semi-natural habitat for housing small, nonhuman primates.

A semi-natural habitat that was designed to house a social group of squirrel monkeys (Saimiri sciureus sciureus) at Goucher College, in Maryland is described. The design could be readily adapted for use with other small primate species.

Animal Husbandry↗
PubMed1992

Striving for safety: experiences of nurses in a hospital under siege.

The hospital in which this study took place served as a centre for emergencies, critically ill patients and maternity cases during a nurses' strike in 98 hospitals in Alberta, Canada. Nurses at this hospital were not members of the striking union; they belonged to their own independent union and they worked throughout the 19-day siege. Thirty-two nurses at the hospital responded to posters seeking volunteers for telephone interviews. The objective of the research was to discover the perceptions and experiences of nurses coping with extraordinarily heavy workloads arising out of a labour dispute. Interview data were gathered and analysed according to the conventions of grounded theory. Nurses voiced many concerns about the care patients received and they coped as best they could in a process described as 'striving for safety'. Fearing they would make mistakes that would harm their patients, they engaged in two subordinate processes of 'assessing competence' and 'preserving integrity'. Several organizational factors were identified that, if present, contributed to nurses' ability to continue or 'hang in' but if absent, contributed to despair or 'feeling demoralized'. The study was exploratory in nature and thus limited, but several implications for supporting nurses and managing such crises were discussed.

Adaptation, Psychological↗
PubMed1992

Accelerated destruction of large, calcified gallstone burdens by performing lithotripsy in the presence of methyl t-butyl ether: an in vitro study.

Numerous, large, or calcified gallstones hinder successful extracorporeal fragmentation. The purpose of this study was to investigate an in vitro method that could accelerate the destruction of these types of gallstone burdens. Matched sets of partially calcified gallstones, each set having a combined stone diameter greater than 3 cm, underwent lithotripsy while immersed in either 15 cc of bile, methyl t-butyl ether (MTBE), or dimethyl sulfoxide (DMSO), with a fourth set serving as a control. Results showed a 20% reduction in the relative weight of all fragments, an eightfold reduction of the relative weight of fragments greater than 3 mm, and a 50% reduction of the number of large fragments when the stones were immersed and shocked in MTBE rather than when shocked in bile. Dimethyl sulfoxide hindered gallstone destruction. These results indicate that large, partially calcified gallstone burdens can be more successfully destroyed if lithotripsy is performed in the presence of a small quantity of MTBE rather than in bile alone or in the presence of DMSO. If proven safe in vivo, this technique could expand the applicability of lithotripsy to those with larger, partially calcified stone burdens.

Cholelithiasis↗
PubMed1992

Fire safety in the operating room.

1. To understand why and how a fire occurs, one needs to look at what is ignited, how it was ignited, and any other factors that may have changed either of these concepts. The three most common ignition sources are lasers, electric cautery equipment, and high intensity light cords. 2. There are four human reactions to fire: disbelief; do nothing; reconsideration of the existence of fire; and taking some action. 3. The best method of fighting a fire is to avoid having one. Emphasis should be placed on prevention. Every OR education program should include elements of a prefire plan that is consistent with the prefire plan for the institution.

Fires↗
PubMed1991

Structure of the membrane-bound protein photosynthetic reaction center from Rhodobacter sphaeroides.

The structure of the photosynthetic reaction center (RC) from Rhodobacter sphaeroides was determined at 3.1-A resolution by the molecular replacement method, using the Rhodopseudomonas viridis RC as the search structure. Atomic coordinates were refined with the difference Fourier method and restrained least-squares refinement techniques to a current R factor of 22%. The tertiary structure of the RC complex is stabilized by hydrophobic interactions between the L and M chains, by interactions of the pigments with each other and with the L and M chains, by residues from the L and M chains that coordinate to the Fe2+, by salt bridges that are formed between the L and M chains and the H chain, and possibly by electrostatic forces between the ends of helices. The conserved residues at the N-termini of the L and M chains were identified as recognition sites for the H chain.

Amino Acids↗
PubMed1991

Comparison of reaction centers from Rhodobacter sphaeroides and Rhodopseudomonas viridis: overall architecture and protein-pigment interactions.

Photosynthetic reaction centers (RCs) from the photosynthetic bacteria Rhodobacter sphaeroides and Rhodopseudomonas viridis are protein complexes closely related in both structure and function. The structure of the Rps. viridis RC was used to determine the structure of the RC from Rb. sphaeroides. Small but meaningful differences between the positions of the helices and the cofactors in the two complexes were identified. The distances between helices AL and AM, between BL and BM, and between bacteriopheophytins BPL and BPM are significantly shorter in Rps. viridis than they are in Rb. sphaeroides RCs. There are a number of differences in the amino acid residues that surround the cofactors; some of these residues form hydrogen bonds with the cofactors. Differences in chemical properties and location of these residues account in some manner for the different spectral properties of the two RCs. In several instances, the hydrogen bonds, as well as the apparent distances between the histidine ligands and the Mg atoms of the bacteriochlorophylls, were found to significantly differ from the Rb. sphaeroides RC structure previously described by Yeates et al. [(1988) Proc. Natl. Acad. Sci. U.S.A. 85, 7993-7997] and Allen et al. [(1988) Proc. Natl. Acad. Sci. U.S.A. 85, 8487-8491].

Amino Acids↗
PubMed1991

Interaction between advancing ice fronts and erythrocytes. Mechanism of erythrocyte destruction upon freezing and influence of cryoprotective agents.

It can be shown theoretically and experimentally that in purely aqueous suspension, cells (as well as microsolutes) are excluded by advancing freezing fronts. This puts the cells under considerable osmotic stress and may be considered to be the major source of cell destruction upon freezing. It is also shown theoretically and experimentally that in aqueous suspensions, admixed with appropriate concentrations of a cryoprotectant (e.g., glycerol), cells are engulfed by advancing freezing fronts: Under such conditions, cells do not undergo any osmotic stress and remain undamaged when frozen. The influence of various common cryoprotectants is discussed, as is the reason why penetrating as well as nonpenetrating agents can be equally effective cryoprotective agents. The reason why leukocytes require lower cryoprotectant concentrations than erythrocytes is also elucidated.

Cell Communication↗
PubMed1990

Nursing education application of a computerized nursing expert system.

Nurse educators are required to be knowledgeable about a wide variety of complex health care problems in order to provide quality education. At the same time, they are given a multitude of other responsibilities such as participating in scholarly activity, advising students, maintaining an active role in nursing practice, and performing community service. These educators must find innovative ways to present current lectures while at the same time meeting their other obligations. The use of Creighton Online Multiple Modular Expert System (COMMES), a computerized decision support consultant, was evaluated as a technique for faculty use in developing and organizing new lecture content. The study found that COMMES was beneficial as a systematic prompt for lecture content, as a tool for organizing content, and as a means to verify completeness of lecture material.

Curriculum↗
PubMed1989

Structure of spheroidene in the photosynthetic reaction center from Y Rhodobacter sphaeroides.

The structure of the reaction center of Y Rhodobacter sphaeroides has been solved at 3 A resolution, using the atomic coordinates of the reaction center from the carotenoidless mutant R26 Rhodobacter sphaeroides. The structure has been refined by a stimulated annealing with the computer program X-PLOR, leading to a crystallographic R factor of 0.22 using reflections between 8 and 3 A. The spheroidene molecule which is bound to the Y reaction center has been fitted in the electron density map as a 15-cis isomer with a highly asymmetric structure. The cis-bond is located at proximity from ring 1 of the accessory bacteriochlorophyll on the inactive M side. The nature of the cis-bond was confirmed by resonance Raman spectra obtained from Y reaction center crystals. The structure of spheroidene in Y reaction center is compared to that proposed for 1,2-dihydroneurosporene in Rhodopseudomonas viridis reaction center crystals.

Bacterial Proteins↗
PubMed1988

From inquiry to judgment: age and sex differences in patterns of adult moral thinking and information-seeking.

This research examined age and sex variations in moral judgment processes across the life-span, primarily using objective questionnaire techniques. Both stage level of judgment and patterns of requests for further information following dilemma presentation were studied in 242 respondents, ages fourteen to ninety-two, in order to measure individual differences in judgment orientations hypothesized by Gilligan and suggested by theorists of aging. There were few indications of sex differences in either stage or patterns of information-seeking, except for a generally greater preference for additional information in decision-making by women. With respect to age trends, participants over age seventy-five scored at significantly lower stage levels than younger adult groups. However, elderly adults' judgments did not appear simply "regressed" to earlier developmental levels. On both objective and open-ended measures, older participants seemed more likely than younger groups to assimilate moral dilemma information to their own general cognitive frameworks, consistent with an hypothesis of greater synthesis in judgment among the elderly.

Adolescent↗