Biomedical subjects
Publications and source records attributed to A McCarthy.
Impaired fetal growth may cause reduced compliance of the aorta and other large arteries, and predispose an individual to higher blood pressure in later life. We found that neither low birth size nor interaction between birth size and adult size were associated with arterial pulse-wave velocity in men and women aged 25 years.
This paper presents the findings of an analysis of the activities of rural nurses from a national audit of the role and function of the rural nurse (Hegney, Pearson and McCarthy 1997). The results suggest that the size of the health service (defined by the number of acute beds) influences the activities of rural nurses. Further, the study reports on the differences of the context of practice between different size rural health services and the impact this has on the scope of rural nursing practice. The paper will conclude that the size of the health service is an outcome of rurality (small population densities, distance from larger health facilities, lack of on-site medical and allied health staff). It also notes that the size of the health service is a major contextual determinant of patient acuity and staff skill-mix in small rural hospitals, and therefore the scope of rural nursing practice.
BACKGROUND: Although Cryptosporidium parvum is known to cause significant morbidity in immunocompromised individuals, including adults with cancer, the epidemiology of this pathogen in paediatric oncology patients is not known. OBJECTIVE: We prospectively investigated the incidence of symptomatic C. parvum infection in children receiving treatment for malignancy. METHODOLOGY: Over a 9 month period, all oncology inpatients with diarrhoea had stool analysis for C. parvum oocysts. The incidence of cryptosporidiosis was also recorded in non-oncology patients who had a stool analysed for C. parvum during the 6 years of the study period. RESULTS: None of the 149 stool samples from 60 oncology patients analysed contained C. parvum oocysts. Thirteen per cent of 173 samples from non-oncology patients were positive for C. parvum oocysts. CONCLUSIONS: In contrast to studies of adult oncology patients, paediatric oncology patients in our institution appear at low risk of cryptosporidiosis.
The population of ammonia-oxidizing bacteria in a temperate oligotrophic freshwater lake was analyzed by recovering 16S ribosomal DNA (rDNA) from lakewater and sediment samples taken throughout a seasonal cycle. Nitrosospira and Nitrosomonas 16S rRNA genes were amplified in a nested PCR, and the identity of the products was confirmed by oligonucleotide hybridization. Nitrosospira DNA was readily identified in all samples, and nitrosomonad DNA of the Nitrosomonas europaea-Nitrosomonas eutropha lineage was also directly detected, but during the summer months only. Phylogenetic delineation with partial (345 bp) 16S rRNA gene sequences of clones obtained from sediments confirmed the fidelity of the amplified nitrosomonad DNA and identified two sequence clusters closely related to either N. europaea or N. eutropha that were equated with the littoral and profundal sediment sites, respectively. Determination of 701-bp sequences for 16S rDNA clones representing each cluster confirmed this delineation. A PCR-restriction fragment length polymorphism (RFLP) system was developed that enabled identification of clones containing N. europaea and N. eutropha 16S rDNA sequences, including subclasses therein. It proved possible to analyze 16S rDNA amplified directly from sediment samples to determine the relative abundance of each species compared with that of the other. N. europaea and N. eutropha are very closely related, and direct evidence for their presence in lake systems is limited. The correlation of each species with a distinct spatial location in sediment is an unusual example of niche adaptation by two genotypically similar bacteria. Their occurrence and relative distribution can now be routinely monitored in relation to environmental variation by the application of PCR-RFLP analysis.
The purpose of the study is to validate the training efficacy of the PC-based Sheffield Knee Arthroscopy Training System (SKATS, as described in MMVR6). Based on a task analysis of real arthroscopy, an evaluation module has been designed to test the core psycho-motor skills used in arthroscopy. The evaluation simulates a joint inspection and triangulation task, which is used to assess the research hypothesis that experienced arthroscopists will perform significantly better on the virtual arthroscopy simulator, than a trainee arthroscopist group and a control group. A group of experienced arthroscopic knee surgeons, a trainee surgeon group and a control group were tested on the simulator. The preliminary results indicate that experienced surgeons performed best with fewer instrument collisions and faster task-completion times. The results indicate that the core skills of arthroscopy used on the SKATS simulator are similar to those used in real arthroscopy. Further validation work is required to assess the training transfer effects. Once the simulator has been validated fully, it may prove beneficial in minimising patient risk.
The apoprotein of flavodoxin from Desulfovibrio vulgaris forms a complex with riboflavin. The ability to bind riboflavin distinguishes this flavodoxin from other short-chain flavodoxins which require the phosphate of FMN for flavin binding. The redox potential of the semiquinone/hydroquinone couple of the bound riboflavin is 180 mV less negative than the corresponding complex with FMN. To elucidate the binding of riboflavin, the complex has been crystallized and the crystal structure solved by molecular replacement using native flavodoxin as a search model to a resolution of 0.183 nm. Compared to the FMN complex, the hydrogen-bonding network at the isoalloxazine sub-site of the riboflavin complex is severely disrupted by movement of the loop residues Ser58-Ile64 (60-loop) which contact the isoalloxazine by over 0.35 nm, and by a small displacement of the isoalloxazine moiety. The 60-loop movement away from the flavin increases the solvent exposure of the flavin-binding site. The conformation of the site at which 5'-phosphate of FMN normally binds is similar in the two complexes, but in the riboflavin complex a sulphate or phosphate ion from the crystallization buffer occupies the space. This causes small structural perturbations in the phosphate-binding site. The flexibility of the 60-loop in D. vulgaris flavodoxin appears to be a contributing factor to the binding of riboflavin by the apoprotein, and a feature that distinguishes the protein from other 'short chain' flavodoxins. In the absence of the terminal phosphate group, free movement at the 5'-OH group of the ribityl chain can occur. Thus, the 5'-phosphate of FMN secures the cofactor at the binding site and positions it optimally. The structural changes which occur in the 60-loop in the riboflavin complex probably account for most of the positive shift that is observed in the midpoint potential of the semiquinone/hydroquinone couple of the riboflavin complex compared to that of the FMN complex.
Whole-embryo culture was used as the model system to study the effects of pulsed ultrasound on embryonic development. Rat embryos (9.5 days old) were exposed to a wide range of ultrasound levels at ultrasound frequencies between 1-4 MHz for 30 min in vitro. After 48 h in culture, absolute control, sham and treatment embryos were assessed for viability, morphology, growth and development. At an ambient temperature of 37 degrees C, no significant effects were observed for spatial peak temporal average intensities below 4 W/cm2 or peak negative pressures below 1.9 MPa. At higher acoustic levels, there was a significant increase in the number of nonviable embryos and the number of morphological abnormalities in viable embryos increased. Abnormal cephalocaudal flexion and abnormal head development were the most common gross morphological abnormalities. Both thermal and nonthermal bioeffect mechanisms are involved.
This literature review is an exploration of issues related to evidence-based practice and rural nursing. Given the contribution that nursing research can make to improved client care in rural areas, it is important that nurses' awareness and understanding of evidence-based practice be enhanced, and that strategies for fostering the development of clinically relevant programs of nursing research be identified for rural health services. The review highlights the deficiencies in the current metropolitan-based approaches to evidence-based practice that may disadvantage rural clients and nursing practitioners, because they do not accommodate the inherent differences in rural and metropolitan healthcare cultures. It emphasises the need to seek approaches to research-based practice that arise from the specific needs of the rural setting.
A novel way of using teicoplanin in situ to treat central venous catheters is described. Profound immunosuppression and the fact that the lines remain indwelling for long periods are two of the main reasons for these infections. In children it is also difficult to prevent these lines being played with, which increases the likelihood of infection. The different types of infection that can occur in a central venous catheter are described and the clinical definition of a catheter infection is provided. In an initial study, infective episodes in a small group of 11 children were treated successfully with in situ amikacin. Most pathogens were Gram-negative cocci. None of the catheters had to be removed, and catheter life was prolonged by a mean of 118 d. Due to the high incidence of Staphylococcus epidermidis in the initial study, in situ teicoplanin was assessed in a subsequent study. Over the course of 1 yr, 20 line infections occurred in 12 children. Empirical amikacin therapy was instituted and switched to teicoplanin once the pathogen was confirmed as Gram-positive. An antibiotic-heparin mixture was introduced into the line and left in place for 24 h, after which time it was replaced with fresh mixture until cultures were sterile. All pathogens were sensitive to teicoplanin, all infections were treated successfully and no catheters had to be removed. Overall, catheter life was prolonged by a mean of 136 d. It was concluded that in situ teicoplanin was effective and well tolerated for line infections (no side-effects were reported during the study). A minimum of 6 d therapy was recommended. The patients with less severe infections would have been suitable for treatment at home by their parents, district nurse or general practitioner (GP).
The objective of this investigation was to measure the quantity of residual blood remaining in neonatal cardiopulmonary bypass (CPB) circuits after they had been drained and to assess the overall significance with regards to total patient blood volume. The residual blood volume left in three infant/neonatal CPB circuits-Medtronic Minimax 3381 (Group MM; n = 5), Polystan Safe Micro (Group SM; n = 6), and Terumo Capiox 308 (Group CX; n = 3)--after they had been drained was determined. This was done by using an electronic scale to weigh the circuit before setup and after CPB when all possible blood was recovered from it. Total priming volume, estimated patient blood volume, residual blood volume, surgical blood loss in theater, and autogeneic blood usage were recorded in each case. Mean residual blood volumes measured were MM = 161 ml (SD 27 ml), SM = 103 ml (SD 19 ml), and CX = 133 ml (SD 15 ml). These volumes were significant, because calculations show that the volume of red cells lost in the circuit is equivalent to fourteen percent of the total patient blood volume. In view of this, neonatal oxygenator design should be minimized to reduce the priming volume and more consideration should be given to ease of residual blood recovery.
A 14-year-old girl presented with symptoms resembling acute appendicitis. Five days after appendectomy and continued fever and severe abdominal pain, blood cultures were found positive for Streptococcus pyogenes. Two days later a diagnosis of group A streptococcal peritonitis with necrotizing retroperitoneal fasciitis was confirmed by retroperitoneal cultures obtained at laparotomy. Although multiple organ systems showed impaired functioning, including hepatic, renal and respiratory changes, she did not meet the criteria for streptococcal toxic shock syndrome. She was treated with a combination of high-dose parenteral penicillin and clindamycin, followed by prolonged treatment with clindamycin orally. Recovery was complicated by persistent hydronephrosis, which was slow to resolve.
OBJECTIVE: Cord entanglement is a common complication of monoamniotic twins and it is associated with high perinatal mortality. Apart from preterm delivery, no treatment has previously been used to reduce the risks of this complication. We postulated that reducing amniotic fluid volume would stabilize fetal lie and reduce the risk of cord compression. STUDY DESIGN: Cord entanglement was documented in three cases of monoamniotic twins in the midtrimester. Sulindac was administered to the mother. Amniotic fluid index, fetal urine output, and umbilical artery and ductus arteriosus Doppler waveforms were investigated before and during treatment by use of real-time and pulsed Doppler techniques. RESULTS: Sulindac was associated with a dose-related reduction in amniotic fluid index and fetal urine production without alteration in fetal flow velocity waveforms. Fetal lie stabilized after commencement of treatment. All six twins were delivered with no complications. CONCLUSION: Medical amnioreduction with sulindac is a new management option in monoamniotic twins to reduce cord complications.
OBJECTIVE: To determine obstetricians personal choices in relation to Down syndrome screening and mode of delivery for themselves or their partners. STUDY DESIGN: Structured anonymous postal survey. All 282 obstetric consultants, senior registrars and registrars in NHS obstetric units within London's M25 region were surveyed. RESULTS: The response rate was 73% (206). Fifty one per cent (105) chose to have elective amniocentesis/CVS without a previous screening test when maternal age was > or = 35 years and 11% (23) when < 35 years. Of the remainder, the majority wanted both maternal serum screening and nuchal translucency rather than a single screening test. In relation to mode of delivery, 17% (33) of obstetricians chose elective caesarean section (CS) in the absence of any clinical indication. Of those who chose CS, 88% did so out of fear of perineal damage. However when faced with a mid-cavity instrumental delivery in the second stage, only 5% (8) wanted CS, the remainder choosing operative vaginal delivery. With an uncomplicated breech presentation, only 27% (55) opted for external cephalic version while 57% (114) chose elective CS. CONCLUSION: This study demonstrates interventionist attitudes among a sizeable percentage of obstetricians in relation to antenatal screening and their own preferred mode of delivery. It suggests that obstetricians regard management options not normally available to pregnant women as valid choices for themselves or their partners.
BACKGROUND: Patients with cancer often receive broad spectrum antibiotics in addition to antineoplastic chemotherapy. Both treatments predispose adult oncology patients to infection and colonization with Clostridium difficile, but the role of this pathogen in pediatric oncology patients is poorly defined. METHODS: A prospective study of 149 fecal samples from symptomatic pediatric oncology patients and 58 samples from asymptomatic patients was performed. Each sample was analyzed for the presence of C. difficile and its toxins A and B. RESULTS: In 8.7% of the symptomatic samples and 19% of the asymptomatic samples toxigenic C. difficile was found. No association was found between either the use of antibiotics and/or the administration of chemotherapy and the presence of toxigenic C. difficile. Younger children were more likely to be infected or colonized with C. difficile, and there was no evidence of nosocomial transmission of C. difficile within the study population. CONCLUSIONS: As toxigenic C. difficile may form part of the normal flora in young children, this study indicates that in the absence of a defined outbreak, C. difficile does not appear to be an important pathogen in pediatric oncology patients.
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This article seeks to review the key concepts and issues central to environmental health in relation to the protection of public health. It will focus on the holistic framework in which environmental health operates and the major threats faced. The key issue to be addressed is the need for collaboration at the professional and organisational level as a central prerequisite for a healthy nation.
The endothelial cells of cardiac capillaries have been reported to swell as a result of ischaemia and reperfusion although there has not previously been any attempt to quantify this observation. Whole capillary and luminal cross-sectional areas, abluminal and luminal membrane lengths were measured from electron micrographs of isolated rat hearts subjected to 30 or 60 min of global ischaemia both with and without subsequent reperfusion for 15 min. All the experimental protocols resulted in capillaries which appeared swollen by electron microscopy. Measurements, however, showed that, after 30 and 60 min ischaemia, this appearance was brought about by a decrease in both whole capillary and luminal area causing an increase in the distance between abluminal and luminal membranes without any change in the endothelial cell cross-sectional area. Reperfusion after 30 min caused an increase in capillary dimensions to larger than control levels. Only after 60 min ischaemia with reperfusion were the cells really swollen with an increase in cross-sectional area. We conclude that (1) we may be observing capillary constriction and (2) the word "swelling" in this context should be used with caution.