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Biomedical subjects

S Ward

Publications and source records attributed to S Ward.

At least 73 records · Page 4Linked to original sources
PubMed2000

Methanococcus jannaschii ORF mj0608 codes for a class C inorganic pyrophosphatase protected by Co(2+) or Mn(2+) ions against fluoride inhibition.

Openreading frame mj0608 of the Methanococcus jannaschii genome, recognized by its sequence similarity to that of the gene coding for class C inorganic pyrophosphatase in Bacillus subtilis, was cloned and over-expressed in Escherichia coli. The protein was purified and characterized by SDS-PAGE, M(r), and N-terminal sequence. Under suitable conditions it catalyzed the specific hydrolysis of PPi at about 600 micromol x min(-1) x mg(-1) at 25 degrees C, and at 8000 micromol x min(-1) x mg(-1) at 85 degrees C. Therefore this protein is a specific inorganic pyrophosphatase. The activities of Mg(2+), Mn(2+), Co(2+), and Zn(2+) ions as cofactors for hydrolysis of PPi were compared at pH 7.5 and 9.0. Unlike the class C pyrophosphatase of B. subtilis, this enzyme required no prior activation by low concentrations of Mn(2+) or Co(2+) ions. However, prior exposure to these ions afforded striking protection against inhibition by sodium fluoride, to which the enzyme was otherwise very sensitive.

Amino Acid Sequence↗
PubMed2000

Changes in gametogenesis and fecundity of acroporid corals that were exposed to elevated nitrogen and phosphorus during the ENCORE experiment.

Colonies of two scleractinian reef coral species, Acropora longicyathus and Acropora aspera were transplanted into patch reefs at One Tree Reef, Great Barrier Reef, Australia as part of the ENCORE experiment. These corals and colonies of A. aspera which were naturally present in the patch reefs were exposed to four treatments over two years: controls with normal seawater, elevated levels of nitrogen only, phosphorus only, or nitrogen plus phosphorus. These corals were sampled and used to determine whether gametogenic cycles and fecundity were affected by nutrient enrichment. Acropora longicyathus had a single annual gametogenic cycle. Corals exposed to elevated nitrogen produced significantly smaller and fewer eggs and contained less testes material than those which were not exposed to nitrogen. Exposure to elevated phosphorus only resulted in corals producing more but smaller eggs, and more testes material. Egg numbers of colonies from other treatments decreased as the gametogenic cycles continued, but those of the phosphorus colonies showed almost no reduction in egg numbers between the early and late stages of the gametogenic cycles. These results have important management implications for coral reefs as they demonstrate that small increases in concentrations of nitrogen and phosphorus can have severe effects on reproductive activity in these species of scleractinian corals.

Journal Article↗
PubMed2000

Preparation of hydrogen from water by reduction with lithium aluminium hydride for the analysis of delta(2)H by isotope ratio mass spectrometry.

An off-line technique is described for the preparation of H(2) from water prior to analysis of delta(2)H by dual-inlet isotope ratio mass spectrometry. H(2) is produced from sample water by reaction with LiAlH(4). This provides a rapid and inexpensive method for the analysis of delta(2)H in small (10 microL) samples of water. Precision was +/- 4.2 to 8.0 (1sigma(n), n = 8) delta(2)H(VSMOW) for samples between 428 and 1500 delta(2)H(VSMOW), +/- 14.5 delta(2)H(VSMOW) for water enriched to 3750 delta(2)H(VSMOW) and +/- 26.0 delta(2)H(VSMOW) for water enriched to 6100 delta(2)H(VSMOW). Accuracy was +/- 1.1 to 4.2 delta(2)H(VSMOW) for water standards from natural abundance to 1000 delta(2)H(VSMOW) (the highest enrichment at which water of accepted delta(2)H is currently available). This method for delta(2)H determination is most appropriate for use with small (<50 microL) samples of high delta(2)H enrichment such as those produced from doubly labelled water studies of small animals. The levels of measurement precision of delta(2)H would contribute 2.6-3.8% to the precision error in estimates of small animal energy expenditure made using the doubly labelled water technique when duplicate analyses are performed.

Aluminum Compounds↗
PubMed2000

An individualized intervention to overcome patient-related barriers to pain management in women with gynecologic cancers.

Concerns about reporting pain and using analgesics ultimately can contribute to poor pain management for many individuals. A nursing intervention to address these "patient-related barriers" was developed based on Johnson's self-regulation theory. The purpose of this pilot study was to determine whether provision of individually tailored sensory and coping information about analgesic side effects and specific information to counter misconceptions would enhance pain management in a sample of 43 women with gynecologic cancers. It was hypothesized that at 1-month post-test and 2-month follow-up, those subjects randomized to the information condition would (a) have lower barriers scores; (b) use more adequate analgesic medication; (c) have lower analgesic side effect scores; (d) have lower pain intensity scores; and (e) experience less pain interference with life and better overall quality of life compared to those in the care-as-usual control group. There was no main effect for group on any of the dependent variables. Rather, all women reported a decrease in barriers between baseline and 2-month follow-up (p<.05); all subjects experienced a decrease in pain interference with life scores between baseline and 1-month post-test (p<.05); and there was a significant shift of women from unacceptable pain management at baseline to acceptable pain management at 1-month post-test (p<.05). In addition, the majority of women reported that the intervention contained novel and useful information that helped them to feel more comfortable taking pain medication, to be less concerned about addiction, and helped them talk more openly about pain with a doctor or nurse.

Adaptation, Psychological↗
PubMed2000

Use of the internet by infertile couples.

OBJECTIVE: To evaluate and compare the extent of Internet use by infertile couples attending a government-funded and a private assisted reproductive technology clinic. DESIGN: A prospective study. SETTING: One private and one public tertiary care fertility clinic in Toronto. PATIENT(S): 250 patients were approached, and 150 (60%) responded. INTERVENTION(S): A self-administered questionnaire on socioeconomic status, fertility history, and computer and Internet use. MAIN OUTCOME MEASURE(S): The extent of Internet use on fertility-related issues was determined, correlated with socioeconomic status and fertility history, and compared between the two clinics. RESULT(S): Higher levels of education, employment, and combined family income characterized patients at the private clinic. A similarly high proportion of patients at both clinics had previous experience with the Internet (mean, 75.3%). Overall, 42% of the total study population and 55.8% of current Internet users had used the Internet for fertility-related issues. Using a logistic regression model, none of the patients' socioeconomic or clinical variables predicted Internet use. Thirty percent of the patients found the Internet helpful in their decision making process. CONCLUSION(S): A considerable proportion of infertile couples from all socioeconomic levels is actively using the Internet with regard to their fertility problems. Health care providers should consider the Internet an important tool for all aspects of their interaction with infertile persons.

Adult↗
PubMed2000

The choice of embryo transfer catheter affects embryo implantation after IVF.

OBJECTIVE: Comparison of two transfer catheters in an IVF program. DESIGN: Prospective, randomized clinical study. SETTING: A private tertiary care center for ART. PATIENT(S): 66 patients < 38 years of age undergoing IVF and/or ICSI. INTERVENTION(S): Patients were randomly assigned to undergo ET using the Tomcat catheter (n = 32) or the TDT catheter (n = 34). MAIN OUTCOME MEASURE(S): Primary outcome measures were implantation and pregnancy rates. Secondary outcome measures were contamination with blood and/or mucus on the tip of the catheter, cramping or patient discomfort, and time required to complete ET. RESULT(S): Use of the Tomcat catheter resulted in significantly higher implantation (25.2% vs. 8.4%) and clinical pregnancy rates (47% vs. 14.7%) compared with the TDT catheter. All secondary outcome measures were similar for both catheters. CONCLUSION(S): The choice of ET catheter may affect the success of IVF-ET cycles. Use of the Tomcat catheter compared with the TDT catheter seems to result in significantly better efficiency of the ET procedure and is more cost effective.

Adult↗
PubMed2000

A global profile of germline gene expression in C. elegans.

We used DNA microarrays to profile gene expression patterns in the C. elegans germline and identified 1416 germline-enriched transcripts that define three groups. The sperm-enriched group contains an unusually large number of protein kinases and phosphatases. The oocyte-enriched group includes potentially new components of embryonic signaling pathways. The germline-intrinsic group, defined as genes expressed similarly in germlines making only sperm or only oocytes, contains a family of piwi-related genes that may be important for stem cell proliferation. Finally, examination of the chromosomal location of germline transcripts revealed that sperm-enriched and germline-intrinsic genes are nearly absent from the X chromosome, but oocyte-enriched genes are not.

Animals↗
PubMed2000

Outcome of paediatric domiciliary mask ventilation in neuromuscular and skeletal disease.

Noninvasive positive pressure ventilation delivered by nasal mask or facemask has been used widely in the last decade to manage chronic ventilatory failure in adults with neuromuscular and chest wall disease. However, it has been thought that paediatric patients would not be able to tolerate masks, and previous anecdotal reports on the paediatric application of mask ventilation have not assessed the effects on nocturnal and arterial blood gas control. Domiciliary mask ventilation has been used in 40 children with ventilatory insufficiency due to congenital neuromuscular and skeletal disease aged 9 months-16 yrs. Eighteen patients had symptomatic nocturnal hypoventilation, 17 had diurnal ventilatory failure, three were referred for weaning and two had frequent chest infections associated with sleep-disordered breathing. Thirty eight of the 40 patients tolerated mask ventilatory support long-term. Diurnal mean+/-SD oxygen tension in arterial blood (Pa,O2) increased from 8.5+/-1.8-10.9+/-1.7 kPa (p<0.001) and mean carbon dioxide tension in arterial blood (Pa,CO2) fell from 7.0+/-1.6-5.9+/-0.8 kPa (p=0.01) following initiation of ventilatory support. Mean and minimum nocturnal Pa,O2 and peak transcutaneous carbon dioxide tension (Ptc,CO2) (n=21) improved significantly. Mask ventilation can be used successfully in young children and reverses ventilatory insufficiency due to congenital neuromuscular and skeletal disease.

Adolescent↗
PubMed2000

Bronchocentric granulomatosis: computed tomographic findings in five patients.

AIM: The aim of this study was to assess the CT manifestations of bronchocentric granulomatosis. SUBJECTS AND METHODS: The CT results of five patients with bronchocentric granulomatosis were retrospectively analysed. The patients ranged from 20 to 72 years of age and included three men and two women. The diagnosis of bronchocentric granulomatosis was made at lobectomy (n = 2), open lung biopsy (n = 2), and transbronchial biopsy (n = 1). Only one of the five patients had asthma. RESULTS: The main findings consisted of a spiculated mass lesion (n = 3) or lobar consolidation with associated mild volume loss (n = 2). One of the two patients with consolidation had extensive mucoid impaction. The abnormalities involved predominantly an upper lobe in four patients and a lower lobe in one patient. In the four resected specimens, the macroscopic pathological appearance was consolidation (n = 2) and mass lesion (n = 2). Microscopically, the typical histology of airway-centred necrotizing granulomata was present in all cases. Aspergillus hyphae were identified in two cases. Nocardia sp. was cultured from the biopsy specimen in one case. CONCLUSION: The CT manifestations of bronchocentric granulomatosis consist of a focal mass or lobar consolidation with atelectasis. These reflect the presence of granuloma formation with or without associated bronchial obstruction.

Adult↗
PubMed2000

Pulmonary complications following lung transplantation.

Lung transplantation has become an accepted procedure for the treatment of end-stage lung disease, being successful in improving the quality and length of life of many patients. The recognition and early treatment of complications is important for long-term survival of lung transplant recipients. The radiologist frequently plays a central role in investigation. The radiological appearance of pulmonary complications arising in the immediate, early (within 2 months) and late (after 2 months) stages post-transplantation are reviewed.

Graft Rejection↗
PubMed2000

Prenatal genotyping for the RhD blood group antigen: considerations in developing an accurate test.

Experience performing prenatal genotyping for RHD has shown that consideration must be given to developing a molecular test capable of detecting recombination/gene conversion events involving the RHD and RHCE genes that can lead to erroneous results. Out of 50 prenatal RHD tests performed over the past 5 years, four samples were encountered that gave false-positive results. In only one of the tests, incorrect results were issued to the physician. In the other three instances, the erroneous nature of the test results was revealed through the analysis of multiple regions of the RHD gene and, more importantly, because the mother, and sometimes the father, were tested in parallel with the fetus. In an extension of the observations obtained from the prenatal testing program, a large panel of RhD-negative blood donors were subjected to molecular analysis of the RHD gene. Of 1,183 donors screened, 187 were found to phenotype as RhD negative. Of the 187 donors confirmed RhD negative serologically, 22 (11.8%) were found to retain remnants of the RHD gene that, depending upon the characteristics of the molecular assay performed, could lead to a false-positive result in a genotyping assay. On the basis of the experience presented here, it is recommended that any molecular RHD assay include an analysis of multiple areas of the RHD gene so as to allow for the detection of recombination/gene conversion events between the RHD and RHCE genes. Moreover, it is strongly recommended that the mother (at a minimum) and father be subjected to molecular analysis simultaneously with the fetus to confirm that the known phenotypes of the parent(s) are consistent with their respective genotypes.

Exons↗