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Biomedical subjects

K Spence

Publications and source records attributed to K Spence.

15 recordsLinked to original sources
PubMed2004

Discovery of a granulovirus of Pandemis pyrusana (Lepidoptera: Tortricidae), a leafroller pest of apples in Washington.

Pandemis pyrusana (Kearfott) is an important leafroller pest of apples in Washington. Surveys for natural enemies discovered a pathogen infecting Pandemis leafrollers in an apple orchard in central Washington. The pathogen was propagated in the laboratory and light microscopy using an azan stain demonstrated that it infected fat body, epidermis, and tracheal matrix cells. The virus was identified morphologically as a granulovirus using electron microscopy and designated PpGV. Rates of infection were determined for each generation in an apple orchard for three years. Infection rates were variable and ranged from 2.6 to 67% of individuals collected from each generation.

Animals↗
PubMed2003

Gastroschisis: determinants of neonatal outcome.

This retrospective study elicits information regarding the dependence of neonatal outcome in gastroschisis upon: (1) the mode of delivery, (2) place of birth, (3) time for birth to surgery, (4) method of closure, (5) time from operation to commencement of first enteral feeds. The neonatal intensive care database from five major tertiary centres was used to identify 181 neonates with gastroschisis from 1990 to 2000. There were 8 deaths. There were no significant differences in outcome for infants delivered vaginally (102) versus Caesarean section (79), those born near the tertiary centre (133) as compared to infants born away (48), ones operated within 7 hours (125) compared with those operated after 7 hours (56), with delayed closure (30) versus primary closure (151). Neonates fed within 10 days of operation (85) had significantly lower incidence of sepsis, duration of TPN and hospital stay when compared to those fed after 10 days (96). Early commencement of feeds decreases the incidence of sepsis, duration of total parenteral nutrition (TPN) and hospital stay. Place of delivery, mode of delivery, time to surgery and type of closure do not influence neonatal outcome.

Delivery, Obstetric↗
PubMed2003

Deep versus shallow suction of endotracheal tubes in ventilated neonates and young infants.

BACKGROUND: Mechanical ventilation is commonly used in Neonatal Intensive Care Units to assist breathing in a variety of conditions. Mechanical ventilation is achieved through the placement of an endotracheal tube (ETT) which is left in-situ. The ETT is suctioned to prevent a build-up of secretions and therefore blockage of the airway. Methods of suctioning the endotracheal tube vary according to institutional practice and the individual clinician performing the task. The depth of suctioning is one of these variables. The catheter may be passed to the tip of the ETT or beyond the tip into the trachea or bronchi to facilitate removal of secretions. However, trauma to the lower airways may result from the suction catheter being passed into the airway beyond the tip of the endotracheal tube. OBJECTIVES: To compare the effectiveness and complications of deep (catheter passed beyond the tip of the ETT) versus shallow (catheter passed to length of ETT only) suctioning of the endotracheal tube in ventilated infants. SEARCH STRATEGY: Using text words and subject headings relevant to endotracheal suctioning, searches were made of the Oxford Database of Perinatal Trials, Cochrane Register of Controlled Trials (The Cochrane Library, Issue 3, 2002), MEDLINE (from January 1966 to December 2002, all languages), CINAHL (from 1982 to 2002). In addition, a call was placed on the list servers, NICU-NET and Neonatal-Talk for unpublished trials, conference presentations and current trials. SELECTION CRITERIA: Controlled trials using random or quasi-random allocation of neonates receiving ventilatory support via an endotracheal tube to either deep or shallow endotracheal suctioning. DATA COLLECTION AND ANALYSIS: No studies were found meeting the criteria for inclusion in this review MAIN RESULTS: No studies were found meeting the criteria for inclusion in this review REVIEWER'S CONCLUSIONS: There is no evidence from randomised controlled trials concerning the benefits or risks of deep versus shallow suctioning of endo-tracheal tubes in ventilated neonates and infants. Further high quality research would be required to conclusively establish whether there are any benefits to deep or shallow suctioning. However, as it may be considered unethical to conduct a trial of deep suctioning given anecdotal evidence regarding possible damage to the airway, it is proposed that a randomised controlled trial comparing deep with shallow suctioning may be considered in a NICU where the standard practice includes a deep suctioning technique.

Humans↗
PubMed2002

Excision duodenoplasty: a new technique for congenital duodenal obstruction.

Slow anastomotic function is a common problem in the management of congenital duodenal obstruction. We describe a simple technique of excision duodenoplasty (ED) that results in a fixed open anastomosis, which facilitates early commencement of feeds and discharge from hospital. A retrospective case-note review (1981-2000) was undertaken to compare the results of ED with side-to-side duodenoplasty (SSD) and diamond-shaped anastomosis (DD). The outcome measures were days to commencement of feeds, duration of total parenteral nutrition (TPN), and length of hospital stay. In ED a 1.0 to 1.5-cm elliptical segment of dilated duodenum is excised. A longitudinal incision is made in the smaller distal duodenum. A side-to-side one-layer anastomosis is performed. The wall of the proximal duodenal stump is thick, and excision of the ellipse keeps the anastomosis open by preventing apposition of the opposing walls. This facilitates good drainage across the anastomosis. The time to onset of feeding was longer after SSD (median 7 days) compared to ED (5 days) and DD (5 days). The total duration of TPN was also longer for SSD (9 days) in comparison to ED (7 days) and DD (7 days). Although the duration of hospital stay was more for SSD (18 days) than ED (13 days) and DD (16 days), this difference was not statistically significant. The ED technique thus gives an equally good result as DD and a better result than SSD. It is simple to perform and to teach.

Analysis of Variance↗
PubMed2000

Ancient Egyptian chronology and the astronomical orientation of pyramids.

The ancient Egyptian pyramids at Giza have never been accurately dated, although we know that they were built approximately around the middle of the third millennium BC. The chronologies of this period have been reconstructed from surviving lists of kings and the lengths of their reigns, but the lists are rare, seldom complete and contain known inconsistencies and errors. As a result, the existing chronologies for that period (the Old Kingdom) can be considered accurate only to about +/-100 years, a figure that radiocarbon dating cannot at present improve. Here I use trends in the orientation of Old Kingdom pyramids to demonstrate that the Egyptians aligned them to north by using the simultaneous transit of two circumpolar stars. Modelling the precession of these stars yields a date for the start of construction of the Great Pyramid that is accurate to +/-5 yr, thereby providing an anchor for the Old Kingdom chronologies.

Journal Article↗
PubMed2000

Nasal versus oral intubation for mechanical ventilation of newborn infants.

BACKGROUND: This section is under preparation and will be included in the next issue. OBJECTIVES: The purpose of the review was to compare the complications associated with intubation by the nasal route with those associated with intubation by the oral route for mechanical ventilation in newborn infants. SEARCH STRATEGY: The standard search strategy of the Neonatal Review Group as outlined in the Cochrane Library was used. This included searches of the Oxford Database of Perinatal Trials, Cochrane Register of Controlled Trials, MEDLINE and CINAHL. A call was placed on the list servers, NICU-NET and Neonatal Talk for unpublished trials, conference presentations and current trials. SELECTION CRITERIA: All trials using random or quasi-random allocation of patients to either the nasal or oral route of intubation were included. Study quality and eligibility were assessed independently by each author. DATA COLLECTION AND ANALYSIS: The standard method of the Cochrane Collaboration and the Neonatal Review Group was used to assess the methodological quality of the included studies. The methodological quality of each study was reviewed by the second author blinded to study authors and institutions. Each reviewer extracted data separately before comparison and resolution of differences. The standard method of the Neonatal Review Group was used to measure the effect of the different routes of intubation, using Relative Risk (RR) and 95% Confidence Intervals (CI). MAIN RESULTS: Only two eligible randomized trials were found. Data from these two trials failed to show significant differences between the oral and nasal route of intubation for mechanically ventilated neonates. The rate of failure to intubate using the nasal route was higher in one study. One study found post extubation atelectasis occurred more frequently in nasally intubated infants who weighed less than 1500 grams. The rates of malposition of the tube at the initial intubation, accidental extubation, tube blockage, re-intubation after extubation, septicaemia, clinical infection and local trauma (nasal erosion or palatal groove) were not significantly different for the two groups. REVIEWER'S CONCLUSIONS: Post extubation atelectasis may be more frequent after nasal intubation, particularly in very low birth weight infants. One route of intubation does not seem to be preferable to the other. There is a need for further randomized controlled trials containing larger numbers of infants.

Humans↗
PubMed2000

Nursing scripts and the organizational influences on critical thinking: report of a study of neonatal nurses' clinical reasoning.

During 1995-1997 a study was undertaken to explore the extent to which theoretical knowledge acquired through a distance education programme in neonatal nursing was brought to bear in the real-world clinical reasoning of course participants. The study utilized a think aloud technique and included both concurrent (on-the-job) and retrospective verbal reports at 0, 6 and 12 months into the programme. Participants (n=4) were also interviewed individually on completion of the study. Results indicated that important inconsistencies existed between participants' theoretical knowledge and their practice; they also pointed to some organizational influences on these theory-practice inconsistencies. Script (or schema) theory provided a useful explanatory framework for these results. The paper includes a brief description of data collection and analysis techniques; its main emphasis, however, is on these theory-practice inconsistencies and their explanation in terms of the nature and acquisition of nursing practice scripts. The implications of nursing scripts for the promotion of critical thinking and evidence-based practice are discussed.

Adult↗
PubMed2000

The best interest principle as a standard for decision making in the care of neonates.

In neonatal care, decisions are made on behalf of newborn infants by their parents or, in some instances, health professionals. This paper examines how the best interest standard is the most appropriate focus for decision-making concerning neonates. The components of surrogate decision-making are discussed from the perspective of the neonate's interests and the contribution of the various persons involved in caring for neonates. An argument is presented for the use of best interests when making decisions and the interpretation of best interests is explored. By examining the ethical approaches using best interests, an argument is put forward for caring as an expression of best interests. How some nurses use the best interest standard in their practice is described. The unique perspective nurses may have because of their philosophy, circumstances, experience and concern for neonates is discussed. Examples are used from the literature to support the argument for nurses being in roles and relationships where the neonate's interests are the basis of practice. How nurses classify infants on the basis of their future outcome is used to illustrate how nurses can apply the best interest standard. Ethical approaches of care and cure are used to show the best interest standard as applied to neonates. Caring as an expression of best interests is recommended for nursing decisions and actions using infant outcomes as a focus for caring and best interests.

Australia↗
PubMed1998

Ethical issues for neonatal nurses.

This article examines the involvement of neonatal nurses in ethical issues, achieved through a survey of Australian neonatal nurses. The aim was to discover if nurses were involved in ethical decisions, to examine various categories of neonates and the concerns that nurses felt about them, and to determine the extent to which nurses saw themselves as advocates. A response rate of 65% was achieved from nurses in two states who worked in intensive care and special care nurseries. The findings show that nurses were more likely to be involved in clinical decision making than in ethical decision making, showed the greatest concern for infants who had an uncertain prognosis, and saw themselves as advocates for their patients. The issues surrounding these findings are examined.

Attitude of Health Personnel↗
PubMed1997

Differential influence of TGFbeta1 and TGFbeta3 isoforms on cell cycle kinetics and postirradiation recovery of normal and malignant colorectal epithelial cells.

PURPOSE: A clonogenic assay was used to determine the effects of the growth factors TGFbeta1 and TGFbeta3 on the radiation responses of a normal rat epithelial cell line (IEC6) and a human colonic carcinoma epithelial cell line (Widr). METHODS AND MATERIALS: The radiation sensitivity and ability to recover from potentially lethal damage (PLD), of preconfluent monolayer cultures, was assessed in the presence of the growth factors for 24 h prior to, during, and after irradiation. RESULTS: The surviving fractions of both cell lines assessed immediately following irradiation were unaffected by TGFbeta1 or TGFbeta3. However, TGFbeta3 (but not TGFbeta1) significantly reduced the amount of PLD recovery in the Widr cells (but not in the IEC6 cells). This was associated with a reduction in the shoulder region of the survival curve, rather than a change in slope. A comparative analysis of the effects of TGFbetas 1 and 3 on cell cycle events in the two cell lines demonstrated significantly more Widr cells in the S phase, in the presence of TGFbeta3 only, compared to the controls. This remained constant both before and immediately following irradiation. In the IEC6 cell line TGFbeta3 produced an increase in the numbers of G1 phase cells, characteristic of a G1 arrest. CONCLUSION: It seems likely that TGFbeta3-induced radiosensitisation in Widr cells, 6 h after a single dose of irradiation, is related to its effects on cell cycle events such that the failure of these cells to arrest in G1, either before or after irradiation, results in significantly reduced recovery from DNA damage. This, however, may not be the only mechanism by which this growth factor produces this effect. Indeed, it will also be necessary to investigate these effects in in vivo models and to determine the response to fractionated irradiation before the potential therapeutic benefit of both the differential effects observed between the two TGFbeta isoforms and also between the malignant and normal cell lines can be fully assessed.

Animals↗
PubMed1997

Continuous infusion therapy with very high purity von Willebrand factor concentrate in patients with severe von Willebrand disease.

Five patients with severe (type III) von Willebrand disease received, by continuous infusion, a solvent-detergent treated von Willebrand factor high purity concentrate to control haemostasis. The clinical indications for treatment included prophylaxis prior to orthopaedic, abdominal and tympanic membrane surgery, and treatment of epistaxis and trauma-related bleeding. Plasma vWf antigen and activity were normalized sooner than factor VIII:C levels after initial bolus followed by infusion of the concentrate. Haemostasis was established in all five patients. The degree of shortening of the bleeding time correlated with concentrate infusion rate and, therefore, with administered dose of high molecular weight multimers. Concentrate clearance decreased over time with continued infusion. The product was shown to be stable and sterile at 24 h after reconstitution with no evidence of neoantigen expression. This report illustrates the effectiveness of high purity vWf concentrate administered by continuous infusion and shows that high-molecular-weight multimers are required to shorten the bleeding time to within the normal range.

Adolescent↗
PubMed1991

Mutation spectrum of copper-induced DNA damage.

The ability of metal ions to damage DNA and cause mutagenesis has been analyzed with reversion and forward mutation assays using single-stranded DNA templates. We previously reported that incubation of phi X174 am3 DNA with Fe2+ in vitro results in mutagenesis when the treated DNA is transfected into Escherichia coli spheroplasts (Loeb, L. A., James, E. A., Waltersdorph, A. M., and Klebanoff, S. J. (1988) Proc. Natl. Acad. Sci. U.S.A. 85, 3918-3922, 1988). We now extend these studies to other metal ions. Of the metal ions tested, copper ions were the most mutagenic; the frequency of mutants produced was equal to or greater than that produced by Fe2+. Mutagenesis by Cu+ was diminished by catalase, mannitol, and superoxide dismutase suggesting the involvement of H2O2, hydroxyl ions, and superoxide, respectively. However, the findings that Cu+ and Cu2+ are nearly equally mutagenic and that the mutagenic activities are not completely inhibited by oxygen free radical scavengers make it unlikely that the mechanism for mutagenesis is simply the production of hydroxyl free radicals. The spectra of mutations produced by either copper ion using the lacZ gene as a target are very similar and differ from those reported with other agents. The predominant mutagenic sequence changes are single-base substitutions, the most frequent being replacement of a template C by a T. This transition presumably results from mispairing of an altered C with deoxyadenosine. Copper-induced mutations are not randomly distributed. Instead, they are found predominantly in clusters suggesting direct interaction of copper ions with specific nucleotide sequences in DNA. Evidence is considered that the high frequency of C----T transitions may be a common manifestation of DNA damage by oxygen radicals.

Bacteriophage phi X 174↗