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Biomedical subjects

R Riley

Publications and source records attributed to R Riley.

At least 19 recordsLinked to original sources
PubMed1999

Intragraft cytokine expression and tolerance induction in rat renal allografts.

BACKGROUND: Intragraft cytokine expression was evaluated in a model of renal transplantation. ACI and Lewis rats were used as donors and recipients, respectively, for heterotopic renal transplantation. METHODS: Treated allograft rats (n=10) received a preoperative dose of rapamycin and cyclosporine, followed by 7 days of cyclosporine postoperatively. Isograft rats (n=5) and control allograft rats (n=4) received no immunosuppression. Sacrifice was performed after 120 days. Expression of interleukin (IL)-4, IL-10, and interferon-gamma (IFN-gamma) transcripts was determined with semiquantitative reverse transcriptase-polymerase chain reaction. RESULTS: All treated allograft rats had normal function with 50% histologic rejection. All isografts had normal function. IL-4 and IL-10 were in greater density in allografts with normal histology, whereas IFN-gamma was only seen in allografts with cellular rejection. No IL-10 was seen in isografts, but IL-4 was detected in 3/5 isografts. CONCLUSIONS: We conclude that the lymphocyte population's elaboration of IL-4 and IL-10 is associated with tolerance, whereas the production of IFN-gamma and absence of IL-4 is associated with histology suggestive of acute cellular rejection.

Animals↗
PubMed1998

Sharing in nursing governance: creating opportunities for change.

Shared governance has created a radical shift in the management and systems thinking of organisations by empowering employees through increased accountability, ownership and decision making. This paper outlines the process of introducing the concept of shared governance to the nursing division of a large not-for-profit private hospital in Victoria. The objectives for change and the philosophy of shared governance are explained so as to clarify the reasons for selection of the shared governance model. The steps involved in planning for the introduction of the change process, implementation and integration of the model at both organisational departmental levels, and the actual structure of the working model of shared governance are described.

Decision Making, Organizational↗
PubMed1998

Physiological cardiac reserve: development of a non-invasive method and first estimates in man.

OBJECTIVE: To investigate whether physiological cardiac reserve can be measured in man without invasive procedures and whether it is a major determinant of exercise capacity. DESIGN: Development of method of measurement and an observational study. SETTING: A regional cardiothoracic centre. SUBJECTS: 70 subjects with a wide range of cardiac function, from heart failure patients to athletes. METHODS: Subjects underwent treadmill, symptom limited cardiopulmonary exercise tests to measure aerobic exercise capacity (represented by VO2max) and cardiac reserve. Cardiac output was measured non-invasively using the CO2 rebreathing technique. RESULTS: Cardiac power output (CPOmax) at peak exercise was found to be significantly related to aerobic capacity: CPOmax (W) = 0.35 + 1.5 VO2max (1/min), r = 0.87, p < 0.001. It also correlated well with exercise duration (r = 0.62, p < 0.001), suggesting that cardiac reserve is a major determinant of exercise capacity. In the study, cardiac reserve ranged from 0.27 to 5.65 W, indicating a 20-fold difference between the most impaired cardiac function and that of the fittest subject. CONCLUSIONS: A non-invasive method of estimating physiological cardiac reserve was developed. The reserve was found to be a major determinant of exercise capacity in a population of normal subjects and patients with heart disease. This method may thus be used to provide a clearer definition of the extent of cardiac impairment in patients with heart failure.

Adolescent↗
PubMed1997

Passive constriction of the upper airway during central apneas: fiberoptic and EMG investigations.

We studied five adult male patients with central sleep apnea syndrome (> 75% of the monitored events being central) during sleep using a fiberoptic scope and EMG monitoring of the superior and middle constrictors of the pharynx and the genioglossus and geniohyoid muscles. The fiberoptic investigation revealed a spontaneous decrease in the size of the airway during central apneas, without negative intrathoracic pressure or activation of the superior and middle pharyngeal constrictor muscles. We found a mean maximum decrease of 71 +/- 7% in the cross-sectional area of the airway and an absence of superior-middle pharyngeal constrictor EMG discharge. We did not observe any complete collapses of the airway.

Adult↗
PubMed1997

Combined radiofrequency ablation-cooling catheter for reversible cryothermal mapping and ablation.

Reversible cryothermal mapping of cardiac arrhythmias has been performed intraoperatively. However, a steerable cooling catheter for reversible mapping has not yet been developed. We therefore developed and tested a cooling system consisting of a -15 degrees C hypertonic saline reservoir and a 7F steerable catheter also capable of radiofrequency (RF) ablation. Using excised ovine hearts placed in a 37 degrees C circulating saline bath, we measured the temperatures at depths of 0 mm, 1 mm, and 2 mm. The temperature after 90 seconds of cooling was 16.5 +/- 2.1 degrees C at 0 mm compared to 23.9 +/- 4.1 degrees C at 1 mm and 31.1 +/- 3.9 degrees C at 2 mm depth (p < 0.01). These data suggest that a 7F steerable combined RF ablation-cooling catheter may achieve temperatures suitable for mapping arrhythmias such as atrial tachycardias and right ventricular outflow tract tachycardias. Further enhancements to achieve lower temperatures at depth may be needed to reversibly map other arrhythmias such as left ventricular tachycardias.

Animals↗
PubMed1996

Radiation therapy for subretinal neovascularization.

PURPOSE: To evaluate low-dose external beam irradiation and plaque radiotherapy for the treatment of subretinal neovascularization. METHODS: The authors treated 137 patients with radiation therapy for subretinal neovascularization. Herein, they examine a subset of 75 patients with exudative age-related macular degeneration who were treated with (4- or 6-MV photons) external beam irradiation at a dose of 1200 to 1500 cGy to the affected macula. In addition, six patients were treated with palladium 103 ophthalmic plaque brachytherapy to an equivalent retinal apex dose of 1200 to 1500 cGy. The authors compared the intralesional, intraocular, and intracranial radiation dose distributions of each treatment modality. Early Treatment Diabetic Retinopathy Study-type visual acuity determinations, ophthalmic examinations, and angiography were performed before and after treatment. Clinical evaluations were performed in a nonrandomized and unmasked fashion. RESULTS: Episcleral plaque brachytherapy was found to provide a higher average radiation dose within the neovascular tissues while delivering less radiation to most normal ocular (both eyes) and all intracranial structures. Both forms of radiotherapy were associated with decreased hemorrhages, exudates, and leakage of neovascular membranes. Ten (13 percent) patients receiving external beam radiotherapy had transient epiphora and ocular irritation. CONCLUSION: Observation and laser photocoagulation of subfoveal neovascularization have been associated with poor visual outcomes. Pilot experience suggests that low-dose radiotherapy offers a method to treat subretinal neovascularization without destroying the overlying retina. Although the authors' radiation distribution studies favored plaque radiotherapy, additional factors such as relative efficacy, expense, convenience, and safety must be investigated.

Aged↗
PubMed1996

A reversible uvulopalatal flap for snoring and sleep apnea syndrome.

Velopharyngeal incompetence (VPI) is a recognized complication of uvulopalatopharyngoplasty (UPPP) for obstructive sleep apnea. A new uvulopalatal flap (UPF) technique that modifies the UPPP and reduces this risk is presented. The technique achieves the same anatomic results as the UPPP but is reversible. To evaluate clinical outcomes of this new procedure, selected variables were compared in patients who underwent UPPP and UPF procedures. Eighty patients were examined (59/80 UPF, 21/80 UPPP) in a prospective and consecutive manner. Subjects underwent polysomnography and extensive airway evaluations. The characteristics of all patients, at baseline, were evaluated. The study variables included age, sex, body mass index (BMI), palatal length (PNS P) in millimeters, respiratory disturbance index (RDI), lowest oxygen saturation during sleep and a subjective snoring scale. Sixty-seven of the 80 patients underwent simultaneous hypopharyngeal surgery. Data were analyzed with a SAS program. No statistical difference existed between groups. The postoperative character of the palate and the change in snoring scores were the same in all patients (p = 0.584). A positive correlation existed between improvement in the snoring score and the amount of tissue removed or repositioned in the patients treated with UPF (correlation coefficient = 0.370, p = 0.004). In contrast, there was a negative correlation in the UPPP group for the same parameters (correlation coefficient = -0.195, P = 0.409). This suggests there was a difference between these two groups despite the fact that the baseline and postoperative lengths, as well as tissue removed or repositioned, were equivalent. This further suggests that the UPF may reduce snoring to a greater extent than the UPPP. No significant complications were seen in either group. There was no evidence of VPI, even in the early postoperative period. The new reported procedure is reversible and conservative and reduces the risk of VPI. Snoring is improved, which is consistent with a decrease in airway resistance or obstruction.

Adult↗
PubMed1996

Mental health statistics, 1982-83 to 1993-94.

The shift toward greater use of general hospitals for the treatment of mental disorders reflects the tendency to admit patients with the most serious diagnoses to psychiatric hospitals. However, admissions to both types of institution now tend to involve more serious cases than in early 1980s. To some extent, the increase in the number of patient-days provided for mental disorders, despite declining separation rates, is attributable to the time required for the treatment of disorders such as schizophrenia and affective psychoses. There is also growing emphasis on community care. Increasingly, mental disorders are treated on an outpatient basis without admission to hospital. The substantial annual fluctuations in the national number of separations-as many as 5,000 or 6,000 from one year to the next-may be due to the development of alternative facilities such as community health clinics. The opening of such a facility in one province could have noticeable impact on national figures on hospitalization for mental disorders.

Canada↗
PubMed1995

IL-7 drives donor T cell proliferation and can costimulate cytokine secretion after MHC-matched allogeneic bone marrow transplantation.

Transplantation of MHC-matched, allogeneic B10.D2 bone marrow plus T cells into BALB/c recipients ultimately results in chronic graft-vs-host disease (GVHD) and mortality 8 to 12 wk post-transplant. We have identified IL-7-specific mRNA in the spleens of BALB/c bone marrow transplantation (BMT) recipients during the first week post-transplant. The response by T cells from B10.D2-->BALB/c BMT recipients to stimulation with IL-7 in vitro during the early period after transplant was then examined. The findings indicated that within the first week post-transplant, spleen cells removed from recipients injected with allogeneic, but not syngeneic, T cells proliferated vigorously to rIL-7. Both IL-2-dependent and -independent components were identified. Depletion of responding cells before culture with anti-Thy-1.2 Ab virtually eliminated this response. We conclude that transplant of allogeneic T cells is required for the observed IL-7 response, and moreover, such cells proliferate after exposure to this cytokine in vitro. To determine whether IL-7 could have a functional effect on donor T cells, the production of IFN-gamma by T cells from allogeneic BMT recipients stimulated with anti-T cell receptor (i.e., anti-V beta) Ab was examined. IL-7 was demonstrated to enhance IFN-gamma production by donor T cells postallogeneic BMT. These results suggest that a cytokine presumably produced in the host for the physiologic function of hematologic reconstitution is playing an additional role during the early events after allogeneic BMT mediated via the expansion and augmented cytokine production by donor T cells.

Animals↗
PubMed1995

Cytogenetic and flow cytometric analysis of a pancreatoblastoma.

A pancreatoblastoma from a 4-year old male was examined by flow cytometric ploidy analysis and cytogenetics. To detect differences within the tumor, the specimen was divided into four portions and sampled separately. Flow analysis revealed that each sample contained a diploid and a tetraploid population of tumor cells. These findings correlated well with the cytogenetic analysis, which also revealed differences in structural rearrangements between samples. A t(13;22)(q10;q10) was the only rearrangement found in near-diploid cells as well as one near-tetraploid line. Other common structural changes in near-tetraploid cells included t(13;13)(q10;q10), i(6p)(p10), and del(1). Chromosomes 1, 6, 13, and 22 were consistently missing from all near-tetraploid cells lines. To our knowledge, this is the first flow cytometric and cytogenetic study of a pancreatoblastoma.

Child, Preschool↗
PubMed1995

Aboriginal wellbeing and liquor licensing legislation in Western Australia.

This paper is based on the results of a project undertaken as the basis for a submission to the committee established to review the Western Australian Liquor Licensing Act 1988. It reports on key issues relating to liquor licensing, as identified by members of regional Aboriginal organisations. Among these issues are the promotion of alcohol consumption and misuse, discriminatory practices by licensees and the police and the need for greater community involvement in liquor licensing decisions. To address these issues, members of the participating organisations proposed: inclusion of a harm-minimisation objective in the Act, education and training programs for the public, licensees and the police, and industry funding for harm-minimisation programs.

Alcohol Drinking↗
PubMed1995

Serum G-CSF levels in patients undergoing G-CSF/chemotherapy mobilized peripheral stem cell harvest and predictors of neutrophil and platelet recovery.

Granulocyte colony-stimulating factor (G-CSF)/Chemotherapy mobilized peripheral blood progenitors are an effective source of stem cells which affords rapid and complete hematopoietic engraftment after myeloablative chemotherapy regimens. The dose of G-CSF most commonly used for mobilization is 5 micrograms/kg. We measured G-CSF levels in patients with chemosensitive malignancies undergoing peripheral stem cell harvest to determine whether there was a relationship between serum G-CSF levels and the yield of CD34+ hematopoietic progenitors. Peripheral blood stem cells (PBSCs) were mobilized by chemotherapy followed by G-CSF (5 micrograms/kg) started 24 hours after completion of chemotherapy. PBSCs were collected by daily leukapheresis during G-CSF stimulation once the WBC had recovered to 1.0 x 10(9)/L, with 10 liters of blood processed using a Fenwall CS 3000. G-CSF levels were monitored daily before and after leukapheresis. CD34+ cells from daily leukapheresis collections were determined in 11 patients. Immunophenotyping analyses of CD34+ and non-CD34+ cells for surface antigens CD38+, HLA-DR, CD71+, CD61+ and CD42a+ were performed on these daily leukapheresis. The mean (SD) number of days to neutrophil recovery (NR: > or = 0.5 x 10(9)/L) after stem cell reinfusion was 9.2 (1.92). The corresponding values for platelet recovery (PR: > or = 20 x 10(9) L) were 8.1 (2.39) days. Using multiple regression analyses, the best predictors for NR were: last G-CSF (R2 = 0.21); last G-CSF and CD34+ (R2 = 0.67); last G-CSF, CD34+ and number of chemotherapy cycles (R2 = 0.72).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Soluble and membrane-bound TNF-alpha are involved in the cytotoxic activity of B cells from tumor-bearing mice against tumor targets.

Splenic B cells from BALB/c mice bearing mammary adenocarcinomas are capable of performing Ab-dependent cellular cytotoxicity. Effector-target conjugation after 18 h results in minimal cytoplasmic damage, whereas extensive nuclear disintegration is observed. To determine whether splenic B cells from tumor-bearing mice can effect direct cytotoxicity against tumor cells, L929 and WEHI 164 cells were used as targets. B lymphocytes from tumor-bearing mice, but not from normal animals, were capable of lysing these two types of tumor cells. However, only a low level of cytotoxicity could be detected when the nontumorigenic 3T3 cells were used as targets. To elucidate the mechanism of cytotoxicity of these killer B cells, RNase protection assays were performed using perforin, granzyme A, TNF-alpha, and lymphotoxin probes. No perforin, granzyme A, or lymphotoxin RNA could be detected in purified preparations of B cells from normal and tumor-bearing mice. B cells from normal mice did not have TNF-alpha RNA. In contrast, B cells from tumor bearers expressed TNF-alpha RNA. TNF-alpha could be detected in supernatants from both unstimulated and stimulated tumor bearers' splenic B cells, as measured by ELISA, and its lytic activity was neutralized by anti-TNF-alpha Ab. Western blots revealed the presence of TNF-alpha on the surface of the killer B cells. Paraformaldehyde-fixed B cells from tumor-bearing mice but not from normal animals were able to lyse TNF-alpha-sensitive tumor targets. This cytotoxicity was neutralized by anti-TNF-alpha Ab. These results suggest that TNF-alpha in soluble and membrane-bound forms may be involved in the mechanism of cytotoxicity exerted by B cells from tumor-bearing mice.

Animals↗