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Biomedical subjects

A Jordan

Publications and source records attributed to A Jordan.

At least 55 records · Page 3Linked to original sources
PubMed1998

The Copenhagen Neck Functional Disability Scale: a study of reliability and validity.

OBJECTIVE: To determine whether a newly developed disability scale for patients with neck pain demonstrated acceptable reliability and validity. METHODS: Testing was conducted using three different samples of patients with neck pain (n = 162). Test-retest reliability of the scale was carried out on the same day with one sample (n = 39), and between-day reliability was carried out with another (n = 21). Differential item functioning with regard to the influence of gender and age was carried out with these two patient groups, as was construct validity. Responsiveness was measured using patients participating in a clinical trial involving patients with chronic neck pain (n = 102). Additionally, scale scores were compared with a wide range of physical measurements using the patients in the clinical trial. RESULTS: Short-term, between-day and postal questionnaire reliability coefficients were all extremely high. The Cronbach's alpha coefficient for internal consistency was 0.9 for the entire scale, and the coefficients for individual items were all greater than 0.88. Disability scale scores correlated strongly to pain scores as well as to doctor and patient global assessments, indicating good construct validity. Relative changes in disability scores demonstrated a moderately strong correlation to changes in pain scores after treatment. Scale scores correlated weakly to all physical measurements. CONCLUSIONS: The disability scale demonstrated excellent practicality and reliability. The scale accurately reflects patient perceptions regarding functional status and pain as well as doctor's global assessment and is responsive to change over long periods of time. We feel that this scale can be a valuable tool for the assessment of patients in future clinical trials and quality of care studies.

Adult↗
PubMed1997

B12-dependent ribonucleotide reductases from deeply rooted eubacteria are structurally related to the aerobic enzyme from Escherichia coli.

The ribonucleotide reductases from three ancient eubacteria, the hyperthermophilic Thermotoga maritima (TM), the radioresistant Deinococcus radiodurans (DR), and the thermophilic photosynthetic Chloroflexus aurantiacus, were found to be coenzyme-B12 (class II) enzymes, similar to the earlier described reductases from the archaebacteria Thermoplasma acidophila and Pyrococcus furiosus. Reduction of CDP by the purified TM and DR enzymes requires adenosylcobalamin and DTT. dATP is a positive allosteric effector, but stimulation of the TM enzyme only occurs close to the temperature optimum of 80-90 degrees C. The TM and DR genes were cloned by PCR from peptide sequence information. The TM gene was sequenced completely and expressed in Escherichia coli. The deduced amino acid sequences of the two eubacterial enzymes are homologous to those of the archaebacteria. They can also be aligned to the sequence of the large protein of the aerobic E. coli ribonucleotide reductase that belongs to a different class (class I), which is not dependent on B12. Structure determinations of the E. coli reductase complexed with substrate and allosteric effectors earlier demonstrated a 10-stranded beta/alpha-barrel in the active site. From the conservation of substrate- and effector-binding residues we propose that the B12-dependent class II enzymes contain a similar barrel.

Amino Acid Sequence↗
PubMed1997

Characterization of Escherichia coli NrdH. A glutaredoxin-like protein with a thioredoxin-like activity profile.

Ribonucleotides are converted to deoxyribonucleotides by ribonucleotide reductases. Either thioredoxin or glutaredoxin is a required electron donor for class I and II enzymes. Glutaredoxins are reduced by glutathione, thioredoxins by thioredoxin reductase. Recently, a glutaredoxin-like protein, NrdH, was isolated as the functional electron donor for a NrdEF ribonucleotide reductase, a class Ib enzyme, from Lactococcus lactis. The absence of glutathione in this bacterium raised the question of the identity of the intracellular reductant for NrdH. Homologues of NrdH are present in the genomes of Escherichia coli and Salmonella typhimurium, upstream of the genes for the poorly transcribed nrdEF, separated from it by an open reading frame (nrdI) coding for a protein of unknown function. Overexpression of E. coli NrdH protein shows that it is a functional hydrogen donor with higher specificity for the class Ib (NrdEF) than for the class Ia (NrdAB) ribonucleotide reductase. Furthermore, this glutaredoxin-like enzyme is reduced by thioredoxin reductase and not by glutathione. We suggest that several uncharacterized glutaredoxin-like proteins present in the genomes of organisms lacking GSH, including archae, will also react with thioredoxin reductase and be related to the ancestors from which the GSH-dependent glutaredoxins have evolved by the acquisition of a GSH-binding site. We also show that NrdI, encoded by all nrdEF operons, has a stimulatory effect on ribonucleotide reduction.

Amino Acid Sequence↗
PubMed1997

Detection of isoprene in expired air from human subjects using proton-transfer-reaction mass spectrometry.

A new analytical method using proton-transfer-reaction mass spectrometry (PTRMS) is described for the determination of trace constituents in human breath. PTRMS is sufficiently sensitive and specific that it does not require preconcentration or separation. At its present stage of development it is capable of detecting trace constituents present in air at the part-per-billion level. These capabilities are illustrated for isoprene, one of the most abundant endogenous hydrocarbons. Our results confirm recent observations of a diurnal level variation associated with sleep or wakefulness; a new finding is that young children have much lower levels of isoprene in breath than adults. To address the metabolic origin of human isoprene, we used PTRMS to analyze expired air for allylic C5 alcohols that have been proposed to be non-enzymatic precursors of isoprene. The lack of correlation between peak breath isoprene and these alcohols suggests that the hydrocarbon is formed by some other mechanism.

Adult↗
PubMed1997

Analysis of the effect of prior therapy on progenitor cell yield: use of a chemotherapy scoring system.

A quantitative analysis of peripheral blood stem cell (PBSC) yield, measuring absolute numbers of CD34+ cells x 10(6)/kg and CFU-C x 10(4)/kg was performed in 74 consecutive patients. The interval or 'gap' from the end of previous chemotherapy to the date of priming was recorded in weeks. Geometric mean CD34 and CFU-C values were significantly higher in patients with a score of < or = 60 compared to those with score > 60 (P = 0.003 and 0.02, respectively) and a significant difference in CD34 values was also found when scores of < or = 38 were compared with scores > 38 (P = 0.003), with the difference in CFU-C values approaching significance (P = 0.08). Patients exposed to toxicity factor 4 drugs had significant lowering of both CD34 and CFU-C values (P < 0.001 and P = 0.038) and this emerged as the only independent factor when analysed using linear regression. No significant difference in the geometric mean CD34 or CFU-C values of patients was found in any of the gap categories analysed. Prior exposure to toxicity factor 4 drugs had a significant adverse effect on stem cell yield and should be avoided or minimized prior to stem cell harvesting.

Adolescent↗
PubMed1997

Endogenous production of methanol after the consumption of fruit.

After the consumption of fruit, the concentration of methanol in the human body increases by as much as an order of magnitude. This is due to the degradation of natural pectin (which is esterified with methyl alcohol) in the human colon. In vivo tests performed by means of proton-transfer-reaction mass spectrometry show that consumed pectin in either a pure form (10 to 15 g) or a natural form (in 1 kg of apples) induces a significant increase of methanol in the breath (and by inference in the blood) of humans. The amount generated from pectin (0.4 to 1.4 g) is approximately equivalent to the total daily endogenous production (measured to be 0.3 to 0.6 g/day) or that obtained from 0.3 liters of 80-proof brandy (calculated to be 0.5 g). This dietary pectin may contribute to the development of nonalcoholic cirrhosis of the liver.

Acetone↗
PubMed1997

A comparison of physical characteristics between patients seeking treatment for neck pain and age-matched healthy people.

OBJECTIVE: To compare physical characteristics of the cervical musculature, including maximal isometric strength of the flexors and extensors, relative isometric endurance of the extensors and the active range of motion (ROM) in extension in a group of patients seeking treatment for chronic neck pain and a group of age-matched healthy people. SETTING: Department of Medical Orthopedics, National University Hospital, Denmark. METHODS: One hundred and nineteen chronic neck-pain patients underwent physical testing for active ROM in extension, maximal isometric torque in extension and flexion and relative isometric endurance in extension before entering a clinical controlled trial studying the treatment of chronic neck pain. Their results were then compared with those of 80 age-matched healthy people. RESULTS: The reliability study demonstrated good within-day and day-to-day reproducibility for active ROM. Active ROM was significantly reduced in female patients, but not in all male age groups. Patients exhibited clinically and statistically significant reductions in maximal isometric torque in both the flexors and extensors of the cervical spine, with the greatest reduction seen in the extensor muscle group. Most patient groups demonstrated a significant reduction in relative isometric endurance of the extensors. CONCLUSIONS: In agreement with most low-back comparisons between patients and age-matched healthy people, the greatest relative muscular deficiencies seem to be in the extensor muscle group. Additionally, most patients exhibit a significant decrease in active ROM during extension. The clinical utility of physical measurements has not been firmly established.

Adult↗
PubMed1997

[Nutrition in the etiopathogenesis of chronic inflammatory bowel diseases].

It is currently held that the pathogenesis of inflammatory bowel disease (IBD) involves a complex interaction of host responses, some immunologic and genetically determined, and external influences including microbial and dietary factors. Nutritional surveys and studies testing stepwise exclusion dietary compounds have suggested that dietary factors might be linked to the occurrence of IBD. Food allergy was suggested early as a possible trigger for the inflammatory response; however, no firm evidence has been gathered over the years to substantiate this possibility. The possibility that patients with Crohn's disease may have an unusual premorbid pattern of dietary intake has also been examined since the early seventies. Several groups of investigators report a high intake of refined sugars (i.e. sucrose), recycled cooking oil, a more frequent consumption of fast foods in patients with Crohn's disease and ulcerative colitis respectively. However, a critical comparison of incidence and prevalence studies published from 1976 until 1994 clearly showed no pre-existing nutritional abnormality that has been identified consistently in patients who develop inflammatory bowel disease.

Adolescent↗
PubMed1996

nrdD and nrdG genes are essential for strict anaerobic growth of Escherichia coli.

In Escherichia coli ribonucleotide reduction is catalyzed by two separate enzymes during aerobic and anaerobic growth. The aerobic enzyme is coded by the nrdAB genes, the anaerobic enzyme by nrdDG. We now show that knock-out mutants of either nrdD or nrdG cannot grow during strict anaerobiosis, achieved by inclusion of sodium sulfide in the medium. Interestingly, these mutants grow well under microaerophilic conditions by overproducing the aerobic enzyme. Under such conditions wild-type bacteria turn off nrdAB and switch on nrdDG.

Aerobiosis↗
PubMed1996

Allosteric regulation of the third ribonucleotide reductase (NrdEF enzyme) from enterobacteriaceae.

Enterobacteriaceae contain genes for three separate ribonucleotide reductases: nrdAB code for a class Ia enzyme, active during aerobiosis, nrdDG for a class III enzyme, active during anaerobiosis, and nrdEF for a cryptic class Ib enzyme. The NrdEF enzyme provides the active reductase in other, widely different bacteria. Here, we describe the allosteric regulation of the Salmonella typhimurium NrdEF enzyme. It consists of two tightly bound homodimeric proteins, R1E and R2F. Nucleoside triphosphates (ATP, dATP, dGTP, and dTTP) regulate the substrate specificity by binding to a single site of the R1E protein (one nucleotide per polypeptide). Regulation is similar to that of the NrdAB enzyme, with one major exception: dATP stimulates reduction of CDP (and UDP) under conditions when dATP strongly inhibits all activity of the NrdAB enzyme. The nrdA-coded R1 protein contains a second binding site for dATP (and ATP) that controls general enzyme activity. All known R1E proteins lack the 50 N-terminal amino acids of R1, and we propose that the activity site is located in this area of the protein. The more sophisticated regulation of NrdAB enzymes of eukaryotes provides protection against the possibly harmful overproduction of dNTPs.

Allosteric Regulation↗
PubMed1996

The ribonucleotide reductase system of Lactococcus lactis. Characterization of an NrdEF enzyme and a new electron transport protein.

Escherichia coli contains the genetic information for three separate ribonucleotide reductases. Two of them (class I enzymes), coded by the nrdAB and nrdEF genes, respectively, contain a tyrosyl radical, whose generation requires oxygen. The NrdAB enzyme is physiologically active. The function of the nrdEF gene is not known. The third enzyme (class III), coded by nrdDG, operates during anaerobiosis. The DNA of Lactococcus lactis contains sequences homologous to the nrdDG genes. Surprisingly, an nrdD- mutant of L. lactis grew well under standard anaerobic growth conditions. The ribonucleotide reductase system of this mutant was shown to consist of an enzyme of the NrdEF-type and a small electron transport protein. The coding operon contains the nrdEF genes and two open reading frames, one of which (nrdH) codes for the small protein. The same gene organization is present in E. coli. We propose that the aerobic class I ribonucleotide reductases contain two subclasses, one coded by nrdAB, active in E. coli and eukaryotes (class Ia), the other coded by nrdEF, present in various microorganisms (class Ib). The NrdEF enzymes use NrdH proteins as electron transporter in place of thioredoxin or glutaredoxin used by NrdAB enzymes. The two classes also differ in their allosteric regulation by dATP.

Amino Acid Sequence↗
PubMed1996

Relation of depressive symptoms to the structure of self-knowledge in childhood.

Measures of positive, negative, and total self-complexity (or self-concept differentiation), self-compartmentalization, self-reported negative events, and self-reported symptoms of depression, anxiety, and conduct disorder were completed by 4th-, 6th-, and 8th-grade public school students. Measures of self-complexity and self-compartmentalization related positively to depression. Results were consistent across grade level. Controlling for anxiety and conduct disorder did not attenuate these effects. Results for positive and negative self-complexity were essentially equivalent to those for total self-complexity. Interactions between self-complexity and negative event and between self-compartmentalization and differential importance were not significant. The authors propose that self-complexity in childhood constitutes a response to negative self-relevant information sometimes conveyed by negative events. The authors conjecture that self-complexity does not buffer the impact of negative events in childhood but may serve as a buffer later in life.

Adolescent↗
PubMed1996

Promoter identification and expression analysis of Salmonella typhimurium and Escherichia coli nrdEF operons encoding one of two class I ribonucleotide reductases present in both bacteria.

Salmonella typhimurium and Escherichia coli cells have two different class I ribonucleotide reductases encoded by the nrdEF and nrdAB operons. Despite the presence of one additional ribonucleotide reductase, the nrdAB-encoded enzyme is essential to the aerobic growth of the cell because nrdAB-defective mutants of both species are not viable in the presence of oxygen. Several factors controlling nrdAB gene transcription have been analysed intensively. Nothing is known about the expression of the nrdEF genes. To study this subject, and after cloning of E. coli nrdEF genes and sequencing of their 5' ends, the promoter of this operon has been identified by primer extension in both bacterial species. The +1 position was 691 bp and 692 bp upstream of the translational start points of the nrdE genes of S. typhimurium and E. coli, respectively. Downstream of the +1 position, and before the nrdE gene, two open reading frames (ORFs) of 81 and 136 amino acid residues are present in both bacteria. The synthesis of a polypeptide with a molecular mass of 9 kDa, corresponding to the first of these two ORFs, was observed by using the T7 RNA polymerase expression system. Comparison of the amino acid predicted sequence of this ORF reveals a significant similarity with glutaredoxin proteins. Competitive, reverse-transcription polymerase chain reaction experiments indicate that transcription from the nrdEF promoter normally takes place in wild-type cells. nrdEF transcription is increased by hydroxyurea, which inhibits class I ribonucleotide reductase activity, in both RecA+ and RecA- cells. nrdA(ts) mutants show a higher level of nrdEF transcription than wild-type cells at either the permissive or the restrictive temperature. nrdEF expression was unaffected by changes in DNA supercoiling whether caused by the introduction of either topA::Tn10 and hns::Tn10 mutations or by the inhibition of DNA gyrase with the antibiotic novobiocin. In contrast to the nrdAB genes, the nrdEF operon is not essential to the cells because nrdEF-defective mutants are viable under both aerobic and anaerobic conditions.

Amino Acid Sequence↗
PubMed1996

Developing a new method to record care at home for children with cancer: an example of research and practice collaboration in a regional paediatric oncology unit.

Academics need to address the facilitation of nurses in practice to research and develop the care given to patients if nursing is to move closer towards a research-based profession. This paper describes a project involving collaboration between an academic department of nursing and nurses working in clinical practice providing care at home for children with cancer. The project involved an audit of the nursing care records for the service, and the development of a new style of record-keeping which described and quantified complex nursing care. The authors discuss the method and results of the project, describing the benefits of research and practice collaboration.

Child↗
PubMed1996

Group interviewing for the purpose of selection.

This paper describes the process of utilizing group interview techniques combined with elements of qualitative methodology to facilitate the selection of newly registered nurses for acceptance into a graduate nurse programme. The paper demonstrates the flexibility and adaptability of group interviewing large numbers of candidates for a limited number of positions. It explores the process from a humanistic perspective and identifies the strengths and weaknesses of the instrument, which will enable further refinement and applicability.

Education, Nursing, Graduate↗
PubMed1996

Functional restoration in chronic low back pain.

Conventional treatments have not slowed down the ever expanding low back pain (LBP) problem. Traditional treatment has most probably contributed to the growth of the problem. Therefore, in a search for new solutions, 'functional restoration' has been devised. In connection with chronic LBP the term has been associated with a full-day program lasting from 3 to 5 weeks. It includes multidisciplinary treatment of patients in groups with intensive physical and ergonomic training, psychological pain management, back school, as well as teaching in social/work related issues. The key concepts are 'acceptance of the pain', 'activity', 'self-responsibility', 'multidisciplinary' and 'quantitative functional evaluation (QFE)'. The latter is aimed so that the participants can feel the physical improvement, encouraging them to be able to go back to work, or at least to lead a more active life style. Several controlled studies suggest a lasting effect in terms of regaining their ability to work and improving pain behavior for a good part of disabled chronic LBP patients. However, it is noteworthy that randomized studies seemingly show poorer results than studies not employing randomized controls.

Ergonomics↗
PubMed1996

Rehabilitation of neck/shoulder patients in primary health care clinics.

OBJECTIVE: To review the literature pertaining to neck/shoulder pain and its treatment primarily through rehabilitation. A discussion regarding the theoretical basis for clinical rehabilitation is presented. DATA SOURCE: A Medline literature search was performed. English and Scandinavian language articles were reviewed. Key words included neck/shoulder pain, neck pain, rehabilitation and exercise. STUDY SELECTION: The studies included used rehabilitation of the cervical musculature as the main treatment therapy on patients suffering from neck/shoulder pain as defined by the Standardized Nordic Questionnaires. DATA SYNTHESIS: The relatively new concept of neck/shoulder rehabilitation seems to result in pain reduction, restoration of functional values and psychological benefit for patients suffering from chronic, recurrent, post-traumatic or postoperative neck/shoulder pain. Successful protocols seem to be dependent upon sufficient dosage, duration and a relative disregard of pain. Side effects seem to be rare. CONCLUSIONS: Rehabilitation of patients with neck/shoulder pain offers great promise; sufficient documentation exists to warrant serious consideration from all practitioners in the primary health sector. Future studies will be necessary to further clarify which rehabilitative procedures are most suitable for different patient types.

Arthralgia↗