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Biomedical subjects

R Lowe

Publications and source records attributed to R Lowe.

At least 19 recordsLinked to original sources
PubMed2001

An automated results notification system for PACS.

The purpose of this study was to determine if the interval between an examination being ordered by an Emergency Department physician and his or her review of the report and images could be shortened by notifying the physician that the results were available. This hypothesis was based on work done previously in the Medical Intensive Care Unit that showed that physicians would wait to review results for a time considerably longer than the time required for the radiologist to review the images and provide a preliminary report. The software developments operate properly and show that even simple integration of multiple information systems (PACS, RIS, speech recognition) can provide useful features. Early results indicate that the Emergency Department (ED) physicians prefer the notification system over the previous (travel to check on images and reports) methods. The hypothesized time reductions did occur, although it is not clear that the notification system accounted for all of them. A system for automated notification of radiology results availability has been shown to be possible and practical. To do this automated interaction of 3 systems with a low-level or no electronic integration was required. Although not fully successful for this study, early physician response has been positive, and requests to expand this service hospitalwide now are common.

Emergency Service, Hospital↗
PubMed2001

Low-dimensional manifolds in tropospheric chemical systems.

Ordinary differential equations derived from large nonlinear systems of chemical reactions are computationally expensive to solve because of the large number of coupled species and the large range of time-scales present. The range of time-scales often spans several orders of magnitude leading to stiff systems of equations requiring implicit numerical techniques. The use of slow manifolds for the description of long time-scale chemical processes has two advantages in that it reduces the number of variables required and also the stiffness of the chemical system by assuming that the fast time-scales are in local equilibrium with respect to the slower ones. The method exploits the existence of a low-dimensional manifold within a large-dimensional species phase space onto which the system quickly collapses. This paper investigates the existence of slow manifolds for nonlinear tropospheric chemical systems and presents a simple method for estimating the local dimension of the manifold using linear perturbation theory. The method is demonstrated for several tropospheric mechanisms over diurnal simulations including a subset of the Master Chemical Mechanism describing butane oxidation and the formation of ozone in the troposphere. It is shown that the intrinsic dimension of the slow manifold varies diurnally and depends on photolytic processes and the relative concentrations of major pollutants.

Journal Article↗
PubMed2001

Hypogastric artery embolization in endovascular abdominal aortic aneurysm repair.

PURPOSE: Iliac artery anatomy is a central factor in endoluminal abdominal aortic aneurysm therapy. It serves as the conduit for graft deployment and as the region of distal graft seal. Thirty-eight percent of iliac vessels in our patients require special treatment because of aneurysms, tortuosity, or small size. Bilateral hypogastric artery exclusion has been avoided because of concerns of colorectal ischemia, hip/buttock claudication, and impotence. We suggest that elective, staged, bilateral hypogastric embolization can be performed safely with reasonably low morbidity and can expand the anatomic boundaries for stent-graft abdominal aortic aneurysm repair. METHODS: This study was performed as a retrospective chart review of patients requiring hypogastric artery embolization for endovascular repair of abdominal aortic aneurysms between June 1998 and June 2000. Patients with otherwise appropriate anatomy and common iliac artery aneurysms were informed of the option for stent-graft repair with internal iliac artery embolization with its risks of impotence, hip/buttock claudication, and bowel ischemia. Patients underwent unilateral or staged bilateral coil embolizations of their proximal hypogastric arteries with an approximate 1-week interval between procedures. Hospital and office records were reviewed; phone interviews were performed. Follow-up ranged from 1 to 12 months. RESULTS: During a 24-month period, 65 patients underwent endovascular abdominal aortic aneurysm repair; 18 patients (28%) required hypogastric artery embolization. Seven (39%) of these patients underwent bilateral embolization. There were no episodes of clinically evident bowel ischemia. Lactate levels were normal in all measured patients. Postoperative fevers (> 101.0 degrees F) were documented in 10 (56%) of 18 patients. The average white blood cell count was 12.8 x 10(9)/L (range, 8.5-22.9). There were no positive blood culture results. The return to the full preoperative diet occurred in 1 to 3 days. Hip/buttock claudication occurred in approximately 50% of patients with persistent but improved symptoms at 6 months. Eighty-seven percent of patients had preoperative erectile dysfunction. Only two patients noted worsening of erectile function postoperatively. CONCLUSIONS: Preliminary results indicate that bilateral hypogastric artery embolization can be performed, when necessary, with reasonable morbidity in patients undergoing stent-graft abdominal aortic aneurysm repair.

Aged↗
PubMed2001

Cardiac rupture caused by Staphylococcus aureus septicaemia and pericarditis: an incidental finding.

A 35 year old woman with a long history of intravenous drug abuse presented to a local hospital with severe anaemia, fever, raised markers of inflammation, and positive blood cultures for Staphylococcus aureus. She responded to treatment with antibiotics with improvement in her symptoms and markers of inflammation. Four weeks later a "routine" echocardiogram showed a rupture of her left ventricular apex and a large pseudoaneurysm. There had been no deterioration in her symptoms or haemodynamic status to herald this new development. It was successfully repaired surgically and the patient made a good recovery.

Adult↗
PubMed2000

Two different concentrations of Opti-Plus(R) compared for daily protein cleaning of a disposable contact lens.

The aim of this study was to compare the relative safety, efficacy, comfort, and convenience of the daily use of a pancreatin-based, liquid enzyme daily protein remover (DPR) at two different concentrations for protein cleaning of Group IV disposable contact lenses.We enrolled 73 subjects (146 eyes) into a 3-month, randomized, investigator-masked clinical study comparing a test regimen of DPR (Opti-Plus(R) or Supra-Clens(R)) containing four drops per 10 mL of multifunctional solution (Opti-Free(R)) to a control regimen containing only two drops per 10 mL of multifunctional solution.The liquid enzyme regimens provided safe and effective protein cleaning of the Group IV lenses with no additional cleaning benefit observed at the higher concentration. Three convenience parameters (steps required, time required, and dexterity required) had mean improvements for both regimens at Day 90 compared to baseline (Day 0). Thus, subjects perceived the DPR regimen as more convenient than their pre-study regimen, which required weekly use of an enzymatic cleaning tablet. Comfort remained consistent with baseline levels throughout the study regardless of concentration of DPR for 72 of 73 subjects.This study provided evidence that the daily use of a low concentration pancreatin enzymatic solution admixed with multifunctional solution is well tolerated and provides a more convenient method of achieving simultaneous disinfection and protein cleaning during contact lens storage than enzyme tablets.

Journal Article↗
PubMed2000

Supervising self-supervision: constructive inquiry and embedded narratives in case consultation.

The development of self-supervision has been suggested as a universal supervisory goal. However, the principle of isomorphism suggests that supervisors from different orientations will view this practice quite differently. This article elaborates an approach to self-supervision that is consistent with constructive therapies, though the intention is to provide flexible guidelines that can accommodate a range of supervisory activities. Case consultation is viewed as an "embedded narrative" involving the case story, the therapist story, and the supervision story. A process of "constructive inquiry" is used to connect these stories in order to construct the identity of a self-sustaining therapist. This process requires a conceptual shift from supervising practice to supervising self-supervision.

Family Therapy↗
PubMed1999

Comparison of the breaking strength of polyglactin mesh in urine, serum, and cell culture media.

OBJECTIVES: This study was designed to determine the durability of polyglactin woven mesh in various in vitro environments, including urine, since polyglactin 901 mesh has been considered for implementation in urinary tract reconstruction. METHODS: Segments of 1 x 1-cm sterile woven and knitted polyglactin 910 mesh with and without collagen coating were exposed to the following conditions: dry (at room temperature and at 37 degrees C, humidified air), in porcine and human serum and urine, in porcine urine over a range of pH levels, in infected urine, in cell culture media (MCDB 105 with 5% fetal bovine serum), and in cell culture media with porcine bladder fibroblasts. The mesh breaking strength was measured at 0, 12, 21, 28, and 36 days. RESULTS: The mean breaking strength for dry, room temperature mesh segments measured 350 g for all time intervals. At day 21, the breaking strength for all mesh types in human and porcine serum, cell culture media, and cell culture media with bladder fibroblasts was less than 10% of the control, but the human and porcine urine maintained 12% to 24% of the control breaking strength (this difference did not reach statistical significance). There was no significant difference in the breaking strength in human and porcine urine or human and porcine serum. By day 38, the breaking strength for all mesh types in all solutions was less than 5% of the control breaking strength. The presence of fibroblasts increased the rate of degradation of the mesh compared with the urine, serum, and cell culture media alone. There was a significant prolongation of degradation with decreasing pH, as well as with infected urine. This prolongation was additive; in fact, all mesh types in low pH (5.0), infected urine showed minimal degradation at 38 days. CONCLUSIONS: In acidic infected urine, the durability of polyglactin 910 mesh is significantly prolonged compared with the other conditions tested. Therefore, when used in urinary tract reconstruction, as in other organ systems, the integrity of the polyglactin mesh should diminish rapidly after 3 weeks as long as the urine is kept sterile and a neutral to alkaline pH is maintained.

Animals↗
PubMed1999

HLA associations in type 1 diabetes among patients not carrying high-risk DR3-DQ2 or DR4-DQ8 haplotypes.

Type 1 diabetes is a complex disease where numerous genes are involved in the pathogenesis. Genes that account for approximately 50% of the familial clustering of the disease are located within or in the vicinity of the HLA complex on chromosome 6. Some DRB1, DQA1 and DQB1 genes are known to be involved, in addition to as yet unidentified HLA-linked genes. The DR4-DQ8 and DR3-DQ2 haplotypes are known to confer high risk for developing the disease, particularly when occurring together. Approximately 10% of patients, however, do not carry any of these high-risk HLA class II haplotypes. We have performed genotyping of DRB1, DQA1 and DQB1 alleles in non-DR3-DQ2/non-DR4-DQ8 patients and controls from Sweden and Norway to test if any HLA associations were observed in these patients. Our results clearly demonstrate several statistically significant differences in the frequency of HLA haplotypes between patients and controls. Case-control analysis including the relative predispositional effect test, and transmission disequilibrium test (TDT) analysis in Norwegian type 1 diabetes families revealed that the DQA1*03-DQB1*0301, DQA1*0401-DQB1*0402, DQA1*0101-DQB1*0501, DQA1*03-DQB1*0303 and DQA1*0102-DQB1*0604 haplotypes may also confer risk. Our analyses also supported independent risks of certain DRB1 alleles. The study clearly demonstrates that HLA associations in type 1 diabetes extends far beyond the well-known associations with the DR4-DQ8 and DR3-DQ2 haplotypes. Our data suggest that there is a hierarchy of HLA class II haplotypes conferring risk to develop type 1 diabetes.

Cohort Studies↗
PubMed1997

The beta cell glucokinase promoter variant is an unlikely risk factor for diabetes mellitus. Diabetes Incidence Study in Sweden (DISS).

Glucokinase plays an important role in the regulation of insulin secretion and is therefore an attractive candidate gene for both insulin dependent (IDDM) and non-insulin-dependent (NIDDM) diabetes mellitus. A single G-A nucleotide polymorphism at the -30 position of the beta-cell specific promoter region of the glucokinase gene was previously associated with reduced beta-cell function. In the present study we analysed 268 consecutive newly diagnosed Swedish patients classified with either IDDM (n = 205), NIDDM (n = 31) or unclassifiable (n = 32) diabetes between the ages of 15 and 35 years along with a group of 158 age- and sex-matched control subjects. The beta-cell promoter region was amplified by the polymerase chain reaction and the G-A variant identified by single strand conformational polymorphism. There was no significant difference in allele frequencies of G and A between any of the subject groups and likewise, no significant difference in the frequencies of the G/G, G/A, or A/A genotypes. Eight subjects were homozygous for the less common A allele, five had IDDM and three were control subjects. Our results suggest that the -30 beta-cell glucokinase promoter variant is not associated with IDDM.

Adolescent↗
PubMed1996

Molecular cloning of an avian anti-Müllerian hormone homologue.

Anti-Müllerian hormone (AMH) is responsible for regression of the Müllerian ducts in males during embryonic development. This peptide hormone of the transforming growth factor-beta family is also believed to play a broader role in sex determination, affecting differentiation and morphogenesis of the testes. Accordingly, in mammals, AMH is produced at much higher levels in male fetuses than in female fetuses. In contrast, in birds, both male and female embryonic gonads produce AMH at high levels, although in males it is still responsible for regression of the Müllerian ducts. Its persistent expression by the embryonic ovaries and its role in female sex determination in birds is not understood. We have cloned an avian homologue to AMH. Avian AMH cDNA encodes a 644 amino acid protein that is 42% identical to human AMH overall with increased identity at the carboxyl terminus. Similarities to human AMH include motifs of sequence identity, a conserved putative plasmin cleavage site and cysteine alignments, and similar genomic intron/exon structure. Antibodies to recombinant avian AMH cross-react with recombinant human AMH and were used to show that avian AMH is glycosylated as has been shown for the human form. The avian AMH gene is transcribed in both male and female gonads but not in liver, heart, kidney or muscle.

Amino Acid Sequence↗
PubMed1996

Occupational health nurses and occupational hygiene: a study of South African nurses' attitudes.

The objectives of this study were to assess the current occupational hygiene practices of occupational health nurses and to assess their attitudes to the identification and initial quantification of workplace hazards. A questionnaire was mailed to all occupational health nurses registered with the South African Society of Occupational Health Nurses. Responses were obtained from 221 (53.7%). Responders and non-responders did not differ on key characteristics. Only 14 (6%) of the respondents performed occupational hygiene tasks as part of their routine work and only 31 (14%) volunteered hazard identification and quantification as tasks that would significantly improve practice. Nevertheless, when asked directly, 120 (54%) agreed that occupational hygiene fell into the ambit of occupational health nursing. Over 70% were positive about receiving theoretical and practical hygiene training. Constraints to greater hazard identification included limited time and resources and concern about intruding into the domains of other practitioners. Sufficient numbers of occupational health nurses were interested in identifying hazards in the workplace for training courses to be planned and offered now; however, restraints to practice need to be clarified and removed for these new skills to be used effectively.

Attitude of Health Personnel↗
PubMed1995

Traumatic spinal cord injury and psychological impact: a cross-sectional analysis of coping strategies.

Many studies have suggested a relationship between coping strategies used to deal with stressors and levels of psychological well-being. To explore this further the current study examined such relationships in people who have sustained a spinal cord injury. Measures of psychological impact and coping strategies were taken from those in their sixth week post-injury (N = 41) and those between four and seven years post-injury (N = 30). The results were analysed using stepwise multiple regression. This provided a number of models containing coping strategies that accounted for a certain proportion of the variance in each of the psychological impact variables. While the results help to identify specific coping strategies associated with better adjustment, they also highlight the need to adopt a longitudinal approach in the investigation of psychological responses to spinal cord injury.

Activities of Daily Living↗
PubMed1994

Tumors expressing the cytosine deaminase suicide gene can be eliminated in vivo with 5-fluorocytosine and induce protective immunity to wild type tumor.

Successful expression of the cytosine deaminase (CD) suicide gene in vivo is demonstrated in three weakly immunogenic murine tumor models: the 102 and 205 fibrosarcomas and the 38 adenocarcinoma. Normal mammalian cells do not contain cytosine deaminase, but tumor cells transduced with retroviral vectors containing the CD gene metabolize the relatively nontoxic prodrug 5-fluorocytosine to the highly toxic 5-fluorouracil. In vitro cells expressing the CD gene are killed by 5-fluorocytosine while unmodified cells are not. When injected into syngeneic mice, CD+ tumors can also be eliminated in vivo by systemic treatment with 5-fluorocytosine without significant toxicity to the host. Animals whose CD+ tumors were eliminated with prodrug treatment resist subsequent rechallenge with unmodified wild type tumor. This posttreatment immunity appears to be tumor specific. Applications of the CD system in gene therapy models are discussed.

Animals↗