Polishing the information on silver.
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Bandages↗
Biomedical subjects
D Parsons
Publications and source records attributed to D Parsons.
Comparison of the antioxidant properties of HYAFF-11p75, AQUACEL and hyaluronan towards reactive oxygen species in vitro.
In chronic wounds, a number of host factors are released which perpetuate the inflammatory process, including polymorphonuclear leukocyte (PMN)-derived reactive oxygen species (ROS), such as superoxide radical (O2*-) and hydroxyl radical (*OH) species. The glycosaminoglycan. hyaluronan, has been shown to act as an antioxidant towards ROS, although the potential for biomaterials, such as HYAFF -11p75 (the 75% benzyl ester of hyaluronan) and AQUACEL (carboxymethylcellulose), to act in this manner has yet to be elucidated. This study compared the antioxidant properties of high and low molecular weight hyaluronan (HMWT HA and LMWT HA), HYAFF -11p75, AQUACEL and an AQUACEL /hyaluronan composite (AQUACEL /HA) against O2*- and *OH. The antioxidant capacities of each material were assessed by their ability to inhibit cytochrome C reduction by O2*- fluxes, generated via the oxidation of hypoxanthine by xanthine oxidase, and their inhibition of 2-deoxy-D-ribose degradation by *OH fluxes, generated by the reaction of hydrogen peroxide (H2O2) and iron (Fe2+). All materials studied possessed dose dependent antioxidant properties towards O2*-, with HYAFF 11p75 having the greatest antioxidant potential towards these species, followed by AQUACEL, HMWT HA, AQUACEL /HA and LMWT HA. Only HMWT HA exhibited dose dependent antioxidant properties towards *OH at the fluxes examined. Gas chromatography/mass spectrometry analysis implied that ester bonds between the hyaluronan backbone and benzyl groups of HYAFF -11p75 are highly susceptible to O2*- hydrolysis, with the de-esterified benzyl alcohol being rapidly degraded in the presence of *OH. This data supports the hypothesis that HYAFF -11p75 has greater antioxidant capacity towards O2*-, due to the esterified benzyl groups providing alternative sites for O2*- attack other than the hyaluronan backbone of HYAFF -11p75 itself and explains the inability of HYAFF -11p75 to scavenge *OH, due to benzyl alcohol degradation by *OH. The antioxidant activities of these biomaterials, particularly HYAFF -11p75 and AQUACEL, towards O2*- could be beneficial, as the scavenging of PMN-derived O2*- may remove initial sources of O2*- and further prevent the secondary formation of *OH. These ROS are thought to be a primary causal factor for the extensive degradation and metabolic alterations observed in chronic wounds.
Antioxidants↗
Hippocampal sympathetic ingrowth occurs following 192-IgG-Saporin administration.
Electrolytic lesions of the medial septal region leads to an unusual neuronal reorganization in which peripheral sympathetic fibers, originating from the superior cervical ganglia, grow into the cholinergically denervated areas of the hippocampus. Since these lesions disrupt cells and fibers of passage which are non-cholinergic, there has been a debate whether Hippocampal Sympathetic Ingrowth is due only to cholinergic denervation of the hippocampus. Using the intraseptal administration of 192-IgG-Saporin, a specific cholinergic neurotoxin, we have found that hippocampal sympathetic ingrowth occurs in the cholinergically denervated hippocampus at 4, 8 and 12 weeks post Saporin injection. These results clearly suggest that hippocampal sympathetic ingrowth is due to the specific loss of the cholinergic projection from the medial septum.
Acetylcholine↗
Physico-chemical characterisation of carboxymethylated spun cellulose fibres.
A new fibrous material for the treatment of exudative wounds is characterised in terms of its physico-chemical properties. The chemistry of the material is analysed and its crystalline structure hypothesised. The influence of the structure on the hydration properties of the carboxymethylated cellulose fibre in fabric form is also demonstrated by physical test methods in comparison with fibrous alginate dressings. The methods illustrate the ability of the material to immobilise fluid by gel blocking and suggest how this can be beneficial in the treatment of chronic wounds by protecting the delicate peri-ulcer area from maceration by exudate.
Bandages↗
The CF salt controversy: in vivo observations and therapeutic approaches.
There is controversy over whether abnormalities in the salt concentration or volume of airway surface liquid (ASL) initiate cystic fibrosis (CF) airway disease. In vivo studies of CF mouse nasal epithelia revealed an increase in goblet cell number that was associated with decreased ASL volume rather than abnormal [Cl(-)]. Aerosolization of osmolytes in vivo failed to raise ASL volume. In vitro studies revealed that osmolytes and pharmacological agents were effective in producing isotonic volume responses in human airway epithelia but were typically short acting and less effective in CF cultures with prolonged volume hyperabsorption and mucus accumulation. These data show that (1) therapies can be designed to normalize ASL volume, without producing deleterious compositional changes in ASL, and (2) therapeutic efficacy will likely depend on development of long-acting pharmacologic agents and/or an increased efficiency of osmolyte delivery.
Aerosols↗
Brief report: Lack of correlation between age of symptom onset and contemporaneous presentation.
The parents/guardians of 50 individuals were surveyed using a semistructured interview to determine the feasibility of this method and to establish ages of symptom onset. Thirty-eight informants were able to recall sufficient detail to allow categorization of the age of symptom onset. Chi-square analysis confirmed a significant association between investigators' categorization and informants' categorization. Contemporaneous presentation was indexed using Childhood Autism Rating Scale, the Autism Behavior Checklist, the Conners Hyperactivity Index, and the Ritvo-Freeman Real Life Rating Scale for Autism. No significant correlations were determined between any of these indices of symptom severity and age of symptom onset.
Adolescent↗
Skeletal muscle morphology and exercise response in congenital generalized lipodystrophy.
OBJECTIVE: Congenital generalized lipodystrophy (CGL) is an autosomal recessive genetic disorder characterized by almost complete absence of adipose tissue, muscular appearance, and severe insulin resistance since birth. We investigated whether insulin resistance in CGL patients is associated with abnormal muscle morphology and whether increased muscularity imparts increased muscle strength and exercise capacity RESEARCH DESIGN AND METHODS: We obtained quadriceps muscle biopsies to study muscle fiber types and capillary density in three African-American women (aged 17-20 years) with CGL. We also assessed quadriceps muscle strength, muscle metabolism, and maximal O2 consumption in the patients. RESULTS: Quadriceps muscle biopsies revealed a markedly higher percentage of type II (fast-twitch glycolytic) muscle fibers in patients with CGL versus sedentary young women (75-78 vs. 47-57%, respectively). The capillary-to-fiber ratio (2.7-3.0), however, was normal. Cross-sectional areas of type I (slow-twitch oxidative) (1,262-2,685 microm2) and type II (2,304-3,594 microm2) fibers were far below the normal values (3,811-4,310 and 3,115-4,193 microm2, respectively), suggesting muscle hyperplasia but not hypertrophy The quadriceps muscle strength, as measured by Cybex, was below average; the maximal O2 consumption (23-32 ml x kg(-1) x min(-1)) was also below average. 31P nuclear magnetic resonance spectroscopy of the forearm muscles revealed normal pH and metabolic responses to static and dynamic exercises. CONCLUSIONS: We conclude that insulin resistance in patients with CGL is associated with an increased proportion of type II muscle fibers but not reduced capillary density. Increased muscularity in CGL is due to muscle hyperplasia and is not associated with increased muscle strength.
Adipose Tissue↗
Equine proliferative enteropathy: a cause of weight loss, colic, diarrhoea and hypoproteinaemia in foals on three breeding farms in Canada.
Proliferative enteropathy (PE) is a transmissible enteric disease caused by Lawsonia intracellularis. An outbreak of equine PE was diagnosed in foals from 3 breeding farms. Most foals had been weaned prior to the appearance of clinical signs, which included depression, rapid and marked weight loss, subcutaneous oedema, diarrhoea and colic. Poor body condition with a rough haircoat and a potbellied appearance were common findings in affected foals. Respiratory tract infection, dermatitis and intestinal parasitism were also found in some foals. Haematological and plasma biochemical abnormalities included hypoproteinaemia, transient leucocytosis, anaemia and increased serum creatinine kinase concentration. Postmortem diagnosis of PE was confirmed on 4 foals based on the presence of characteristic intracellular bacteria within the apical cytoplasm of proliferating crypt epithelial cells of the intestinal mucosa, using silver stains, and by results of PCR analysis and immunohistochemistry. Antemortem diagnosis of equine PE was based on the clinical signs, hypoproteinaemia and the exclusion of common enteric infections. Faecal PCR analysis was positive for the presence of L. intracellularis in 6 of 18 foals tested while the serum of all 7 foals with PE serologically evaluated had antibodies against L. intracellularis. Most foals were treated with erythromycin estolate alone or combined with rifampin for a minimum of 21 days. Additional symptomatic treatments were administered when indicated. All but one foal treated with erythromycin survived the infection. This study indicates that equine PE should be included in the differential diagnosis of outbreaks of rapid weight loss, diarrhoea, colic and hypoproteinaemia in weanling foals.
Animal Husbandry↗
Use of the Amplatz thrombectomy device for severe deep venous thrombosis.
Venous thromboembolism is a significant cause of morbidity in the United States. Thrombectomy devices are not currently the standard of treatment in deep venous thromboses. The Amplatz thrombectomy device is used for arterial occlusions and pulmonary emboli, but its regular use in venous thromboses has not been documented in the literature. We report a unique case of treatment of lower extremity deep venous thrombosis with the Amplatz thrombectomy device.
Catheterization↗
End-stage renal disease projections for Canada to 2005 using Poisson and Markov models.
BACKGROUND: End-stage renal disease (ESRD) incidence and prevalence are increasing in many countries worldwide. Due to the high cost of therapy, predicting future numbers of patients requiring dialysis and transplantation is necessary for health care planners. Projecting therapy-specific chronic disease prevalence is inherently problematic, and examples of suitable models and their application are sparse. When applied, rarely was the adequacy of such models evaluated. METHODS: We describe and illustrate a method for projecting therapy-specific ESRD prevalence in Canada for 1995-2005 using data obtained from the Canadian Organ Replacement Register. The projections combine the Poisson model for incidence rates and a Markov model for patient follow-up. Model adequacy is empirically validated by data-splitting. RESULTS: Large increases in ESRD prevalence are expected in Canada, with an average annual increase of 6.9% projected for 1995-2005. Upon validation, the projection model based on 1981-1987 data was able to predict 1994 prevalence within 1%, while projected therapy-specific prevalences closely approximated those observed. CONCLUSIONS: Therapy-specific ESRD prevalence was successfully projected using Poisson and Markov models. Where multistate prevalence forecasts are required, the method could be augmented for application to various other chronic diseases.
Adult↗
The effect of patellar taping on the onset of vastus medialis obliquus and vastus lateralis muscle activity in persons with patellofemoral pain.
BACKGROUND AND PURPOSE: The purpose of this study was to investigate the effect of patellar taping on the onset of activity of the vastus medialis obliquus muscle (VMO) and the vastus lateralis muscle (VL). SUBJECTS AND METHODS: Fourteen female subjects with patellar pain walked up and down stairs in two conditions: (1) with the patellofemoral joint of the painful lower extremity taped so that the pain was reduced by at least 50% on a pain provocation test and (2) without patellar taping. RESULTS: When the patellofemoral joint was not taped, there was no difference in the onset of activity between the VMO and the VL during the step-up and step-down tasks. During the step-up task, the onset of VMO activity occurred earlier with taping but there was no change in the onset of VL activity with taping. During the step-down task, the onset of VMO activity occurred earlier and the onset of VL activity was delayed with taping. When the patellofemoral joint was taped, the VMO was activated earlier than the VL during the step-up and step-down tasks. CONCLUSION AND DISCUSSION: Taping of the patellofemoral joint in the manner used in this study changed the timing of VMO and VL activity in subjects with patellofemoral pain during step-up and step-down tasks. The earlier activation of the VMO may alter the movement of the patella, and further research is needed to determine whether this occurs and whether it is beneficial.
Adolescent↗
Sodium sensitivity in young adults with high resting end-tidal CO2.
BACKGROUND: Previous research with normotensive adults aged over 40 years ('older') found that sensitivity of blood pressure of subjects with high resting end-tidal partial pressures of CO2 to high sodium intake was greater than normal. OBJECTIVE: To test the hypothesis that the lesser sensitivity of blood pressure of young normotensive adults to high sodium intake is also a function of resting end-tidal partial pressure of CO2. DESIGN: Forty-eight Caucasian men and women (age 28.5 +/- 1.4 years) had a lower than normal dietary intake of sodium chloride for 4 days, and then ingested sodium chloride capsules for 7 days (an additional 190 mmol/day sodium chloride). Resting end-tidal partial pressure of CO2 and blood pressure, and 24 h ambulatory blood pressure, were measured before and after the high-sodium diet. Overnight urine samples were collected before and after the high-sodium diet to determine dietary compliance, and to assess changes in urinary excretion of endogenous digitalis-like factors (a ouabain-like factor, and a marinobufagenin-like factor) that covary with plasma volume. RESULTS: Subjects with high end-tidal partial pressures of CO2 had lower resting heart rates and lower urinary excretion of ouabain-like factor before sodium loading. Sodium loading decreased mean partial pressure of CO2 (by 0.8 +/- 0.2 mmHg) and increased only ambulatory systolic blood pressure (by 2.1 +/- 0.8 mmHg) for the whole group. However, the changes in resting systolic (r = 0.32, P < 0.025) and diastolic (r = 0.36, P < 0.01) blood pressures and in 24 h systolic (r = 0.28, P < 0.05) blood pressure after sodium loading were all positive functions of individual resting end-tidal partial pressures of CO2. Sodium loading increased urinary excretion of marinobufagenin-like factor (by 1.78 +/- 0.88 nmol) and the magnitude of the individual increase was a function of end-tidal partial pressure of CO2. CONCLUSIONS: The results indicate that a high resting partial pressure of CO2 augments the effects of high sodium intake on plasma volume, levels of endogenous digitalis-like factors, and blood pressure in young normotensive humans.
Adult↗
The use of group process in the education of renal patients and families: a multi-centred collaborative approach.
As health care systems are redefined in the 1990s, and as resources decrease, group work is effective as an intervention. Social workers from three acute care hospitals utilized group process as the primary theoretical framework to develop a four-week education/support program for renal patients and families. In collaboration with other health care team members, program format and content were defined within a group development model. In addition, an understanding of the adjustment process, and educational and emotional needs of group participants were inherent in the planning. Interdisciplinary team members from three centres shared responsibility for the agenda which created greater investment and ownership. Evaluation of the program incorporated patient and family feedback from each session and, as a result, content was further developed and refined. This collaborative approach has become a standard component of renal care in the community. However, the integrity of each centre's nephrology program has been maintained. This article describes an educational program for renal patients and families which was developed collaboratively by three nephrology programs. Data collected from 1993 to 1997 have been incorporated.
Adult↗
Healthcare in the United States and the practice of laboratory medicine.
US healthcare and the impact of the changes in the healthcare system on the current and future practice of laboratory medicine are analyzed. Factors considered include--population and government, healthcare expenditure, organization of healthcare delivery (institutions, personnel, healthcare industry, knowledge-personnel production, financing), the impact of managed care, and political and public health issues. The effect of the changing healthcare scene on laboratories and the consequent cost-containment measures for laboratory medicine are examined, including centralization, consolidation, supplier relationships, reengineering and automation (total lab automation), expert systems, CQI, and the move to point-of-care testing.
Clinical Laboratory Techniques↗
The addition of continuous intravenous infusion of ketorolac to a patient-controlled analgetic morphine regime reduced postoperative myocardial ischemia in patients undergoing elective total hip or knee arthroplasty.
This double-blind randomized trial assessed the effect of adding an intravenous continuous infusion of ketorolac to a patient-controlled analgesia (PCA) morphine regimen on analgesia, heart rate, arterial blood pressure, and postoperative myocardial ischemia. Patients having elective total hip or knee replacement were randomized to receive ketorolac 30 mg bolus, followed by an infusion of 5 mg/h for 24 h or placebo. All patients had access to PCA morphine (20 microg/kg bolus, with a lockout of 6 min). Patients were monitored for pain visual analog scale, blood pressure, heart rate, and ST segment depression via a continuous Holter monitor. ST depression of 1 mm 60 ms after the J point was considered significant if it lasted more than 1 min. There was no difference in demographics, risk factors, or cardiac medications between the groups. Ketorolac-treated patients had significantly better pain control at 2, 6, and 24 h. There was significant morphine sparing at all times after 3 h. There was no difference in the number of ischemic events between the groups. The ischemic episodes of the patients who received ketorolac occurred at slower heart rates (97 +/- 15 vs 114 +/- 16 bpm, P = 0.001) than those of patients in the placebo group. The duration of ST depression was shorter in ketorolac-treated patients (24 +/- 35 vs 76 +/- 95 min, P < 0.05). All ST depressions were clinically silent. Logistic regression of factors predicting ischemia included the use of calcium channel blockers and low pain score. These results suggest that analgesia with ketorolac reduces the duration of ischemic episodes in the first 24 h postoperatively.
Aged↗
Marginally effective medical care: ethical analysis of issues in cardiopulmonary resuscitation (CPR)
Outcomes from cardiopulmonary resuscitation (CPR) remain distressingly poor. Overuse of CPR is attributable to unrealistic expectations, unintended consequences of existing policies and failure to honour patient refusal of CPR. We analyzed the CPR outcomes literature using the bioethical principles of beneficence, non-maleficence, autonomy and justice and developed a proposal for selective use of CPR. Beneficence supports use of CPR when most effective. Non-maleficence argues against performing CPR when the outcomes are harmful or usage inappropriate. Additionally, policies which usurp good clinical judgment and moral responsibility, thereby contributing to inappropriate CPR usage, should be considered maleficent. Autonomy restricts CPR use when refused but cannot create a right to CPR. Justice requires that we define which medical interventions contribute sufficiently to health and happiness that they should be made universally available. This ordering is necessary whether one believes in the utilitarian standard or wishes medical care to be universally available on fairness grounds. Low-yield CPR fails justice criteria. Cardiopulmonary resuscitation should be performed when justified by the extensive outcomes literature; not performed when not desired by the patient or not indicated; and performed infrequently when relatively contraindicated.
Beneficence↗
Efficacy of apraclonidine ophthalmic solution (Iopidine) in presumed silicon oil-induced glaucoma and primary open-angle glaucoma.
BACKGROUND: This pilot study evaluated the acute effects of topical ocular apraclonidine 1% (Iopidine) in 10 patients with presumed silicone oil-induced secondary glaucoma (SOIG) and in 10 patients with high-pressure primary open-angle glaucoma (POAG) despite maximum tolerated medical therapy. METHODS: Intraocular pressure (IOP) measurements were carried out before and 1, 2 and 3 h after a single drop of apraclonidine. RESULTS: Patients with SIOG presented with a mean IOP of 30.0 +/- 2.8 mmHg, which was reduced to 21.7 +/- 2.9 mmHg (P < 0.001) after 1 h, to 20.4 +/- 2.3 mmHg (P < 0.001) after 2 h and to 20.0 +/- 2.5 mmHg (P < 0.001) after 3 h. In the POAG group, IOP was reduced from 25.9 +/- 1.9 mmHg before treatment to 18.9 +/- 1.4 mmHg after 1 h (P < 0.001), 17.7 +/- 1.2 mmHg after 2 h (P < 0.001) and 16.9 +/- 0.9 mmHg after 3 h (P < 0.001). There were no significant changes in blood pressure or pulse rate. CONCLUSION: This study confirmed the activity of apraclonidine as an IOP suppressant.
Adolescent↗
Continuous intravenous administration of ketorolac reduces pain and morphine consumption after total hip or knee arthroplasty.
The purpose of this study was to determine the analgesic efficacy, opioid-sparing effect, and tolerability of ketorolac administered as an intravenous (i.v.) bolus followed by a continuous infusion after total hip or knee arthroplasty. After general anesthesia, patients received either placebo or ketorolac 30 mg i.v. as a bolus over 15-30 s followed by a continuous i.v. infusion of ketorolac 5 mg/h for 24 h. All patients received patient-controlled i.v. morphine with no background infusion. Patients were assessed at 2, 4, 6, and 24 postoperatively with respect to analgesia, morphine consumption, side effects, and blood loss. Patients receiving ketorolac reported were less sedated and required fewer antiemetics. There was no difference in blood loss. Patients receiving ketorolac reported better analgesia and used less morphine (35% for hips and 44% for knees) than those receiving placebo.
Aged↗