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Biomedical subjects

E Burgess

Publications and source records attributed to E Burgess.

At least 37 records · Page 2Linked to original sources
PubMed1998

Charged beads enhance cutaneous wound healing in rhesus non-human primates.

Enhanced cutaneous wound healing by positively charged cross-linked diethylaminoethyl dextran beads (CLDD) was studied in a standardized incisional wound model in 20 adult and 20 geriatric Macaca mulatta (rhesus) partitioned equally over five time periods. Physiologic saline served as a control. Soft-tissue linear incisions were prepared between and 1 cm inferior to the scapulae. There were four incisions per rhesus; each incision was 1.5 cm long with 1 cm of undisturbed tissue between incisions, and both the experimental CLDD and physiologic saline treatments were administered to each rhesus. The incision treatments were either CLDD and soft-tissue closure with 4-0 BioSyn sutures or sterile physiologic saline and closure with 4-0 BioSyn sutures. The hypothesis was CLDD would enhance cutaneous wound repair. Verification of the hypothesis consisted of clinical examinations and histologic and tensiometric evaluations on biopsy specimens at 10 and 15 days, whereas 5-day and 2- and 4-month groups were assessed clinically and biopsy specimens were assessed histologically. The clinical course of healing for all groups was unremarkable. At 10 days, incisions in adult rhesus treated with CLDD had a 30-percent greater tensile strength compared with the physiologic saline-treated incisions (p = 0.01), whereas for geriatric rhesus, the CLDD treatment proved to be 15 percent greater in tensile strength compared with the physiologic saline cohort (p = 0.11). By day 15, incisions in adult rhesus were 26 percent stronger than the saline treatment group (p = 0.07), and the difference was 36 percent (p = 0.02) for the geriatric rhesus. From 5 through 15 days, histologic observations revealed a gradual decrease in quantity and integrity of CLDD, with no remnants of CLDD at either 2 or 4 months. Macrophages and multinucleated giant cells were localized in the dermis and were associated with the CLDD. These cells decreased commensurately with the decrease of CLDD beads. The data suggest that CLDD can enhance significantly the tensile properties of healing cutaneous wounds in both adult and geriatric rhesus. Moreover, if the wound healing is enhanced in geriatric patients, this finding may be clinically germane to conditions where wound healing is compromised, such as in diabetics and patients on steroids.

Animals↗
PubMed1997

Report of the Canadian Hypertension Society Consensus Conference: 3. Pharmacologic treatment of hypertensive disorders in pregnancy.

OBJECTIVE: To provide Canadian physicians with evidence-based guidelines for the pharmacologic treatment of hypertensive disorders in pregnancy. OPTIONS: No medication, or treatment with antihypertensive or anticonvulsant drugs. OUTCOMES: Prevention of maternal complications, and prevention of perinatal complications and death. EVIDENCE: Pertinent articles published from 1962 to September 1996 retrieved from the Pregnancy and Childbirth Module of the Cochrane Database of Systematic Reviews and from MEDLINE; additional articles retrieved through a manual search of bibliographies; and expert opinion. Recommendations were graded according to levels of evidence. VALUES: Maternal and fetal well-being were equally valued, with the belief that treatment side effects should be minimized. BENEFITS, HARMS AND COSTS: Reduction in the rate of adverse perinatal outcomes, including death. Potential side effects of antihypertensive drugs include placental hypoperfusion, intrauterine growth retardation and long-term effects on the infant. RECOMMENDATIONS: A systolic blood pressure greater than 169 mm Hg or a diastolic pressure greater than 109 mm Hg in a pregnant woman should be considered an emergency and pharmacologic treatment with hydralazine, labetalol or nifedipine started. Otherwise, the thresholds at which to start antihypertensive treatment are a systolic pressure of 140 mm Hg or a diastolic pressure of 90 mm Hg in women with gestational hypertension without proteinuria or pre-existing hypertension before 28 weeks' gestation, those with gestational hypertension and proteinuria or symptoms at any time during the pregnancy, those with pre-existing hypertension and underlying conditions or target-organ damage, and those with pre-existing hypertension and superimposed gestational hypertension. The thresholds in other circumstances are a systolic pressure of 150 mm Hg or a diastolic pressure of 95 mm Hg. For nonsevere hypertension, methyldopa is the first-line drug; labetalol, pindolol, oxprenolol and nifedipine are second-line drugs. Fetal distress attributed to placental hypoperfusion is rare, and long-term effects on the infant are unknown. Magnesium sulfate is recommended for the prevention and treatment of seizures. VALIDATION: The guidelines are more precise but compatible with those from the US and Australia.

Antihypertensive Agents↗
PubMed1997

Natural behavior polymorphism due to a cGMP-dependent protein kinase of Drosophila.

Naturally occuring polymorphisms in behavior are difficult to map genetically and thus are refractory to molecular characterization. An exception is the foraging gene (for), a gene that has two naturally occurring variants in Drosophila melanogaster food-search behavior: rover and sitter. Molecular mapping placed for mutations in the dg2 gene, which encodes a cyclic guanosine monophosphate (cGMP)-dependent protein kinase (PKG). Rovers had higher PKG activity than sitters, and transgenic sitters expressing a dg2 complementary DNA from rover showed transformation of behavior to rover. Thus, PKG levels affected food-search behavior, and natural variation in PKG activity accounted for a behavioral polymorphism.

Animals↗
PubMed1996

Aluminum toxicokinetics.

In this study of the toxicokinetics of aluminum we have examined some of the fundamental issues that currently define our understanding of the toxicology of aluminum in humans. There is a vast literature on this subject, and it was not our aim to review this literature but to use it to develop our understanding of the toxicokinetics of aluminum and to identify critical and unresolved issues related to its toxicity. In undertaking this task we have chosen to define the term toxicokinetics to encompass those factors that influence both the lability of aluminum in a body and the sites at which aluminum is known to accumulate, with or without consequent biological effect. We have approached our objective from the classical pharmacological approach of ADME: the absorption, distribution, metabolism, and excretion of aluminum. This approach was successful in identifying several key deficits in our understanding of aluminum toxicokinetics. For example, we need to determine the mechanisms by which aluminum crosses epithelia, such as those of the gastrointestinal tract and the central nervous system, and how these mechanisms influence both the subsequent transport and fate of the absorbed aluminum and the concomitant nature and severity of the biological response to the accumulation of aluminum. Our hope in highlighting these unresolved issues (summarized in Table 1) is that they will be addressed in future research.

Absorption↗
PubMed1996

Systemic aluminum toxicity: effects on bone, hematopoietic tissue, and kidney.

Although the full mechanisms are not yet elucidated, research into the mechanism of toxicity of aluminum (Al) on bone formation and remodeling and on hematopoietic tissue is ongoing. In contrast little information exists on the interactive effects of systemic Al and the kidney. In bone, both clinically and experimentally, high doses of Al inhibit remodeling, slowing both osteoblast and osteoclast activities and producing osteomalacia and adynamic bone disease. In contrast, while very low levels of Al are mitogenic in bones of experimental animals, the effect of low levels of Al in humans is unknown. Aluminum has been shown to have its mitogenic action at the osteoblast, but whether the effect on resorption is viz osteoblast-directed changes in osteoclast activity has not yet been determined. Parathyroid hormone (PTH) levels are disrupted by Al in humans and animals. Whether altered PTH levels play a major or even a minor role in Al-dependent osteotoxicity requires clarification. In hematopoietic tissue, Al causes a microcytic anemia, not reversible by iron. Friend leukemia cells treated with Al have been reported to accumulate excess iron, without incorporating it into ferritin or heme. It is not yet known which steps in iron metabolism are disrupted by Al, if they involve a single mechanism of action, or even if this disruption in iron metabolism accounts for the anemia seen in Al toxicosis. In kidney, research is needed to evaluate Al nephrotoxicity; there are almost no studies in this area. Furthermore, research is needed to evaluate mechanisms of renal Al excretion, presently shown by one study to occur at the distal tubule. Such studies might well throw light on whether Al plays a role in aggravating renal insufficiency, or whether the role of the kidney in Al toxicosis is limited to the causative effect of renal compromise on Al accumulation. In summary, while a number of mechanisms have been proposed for the toxic action of Al, no single mechanism emerges to explain these diverse effects of systemic Al. Recommendations for future research are presented and summarized in Table 1.

Aluminum↗
PubMed1996

Prevention and treatment of aluminum toxicity including chelation therapy: status and research needs.

The prevention and treatment of aluminum (Al) accumulation and toxicity are reviewed. Recommendations to further our understanding of desferrioxamine (deferoxamine, DFO) treatment and to develop more effective chelation approaches are provided. Reduction of Al accumulation and toxicity may benefit end-stage renal disease (ESRD) patients and perhaps those suffering from specific neurodegenerative disorders as well as workers with Al-induced neurocognitive disorders. The clearance of Al may be increased by extracorporeal chelation, renal transplantation, perhaps complexation with simple ligands such as silicon (Si), and systemic chelation therapy. The abilities of extracorporeal chelation and Si to reduce Al accumulation require further evaluation. Although it may not be possible to design Al-specific chelators, chelators with greater Al selectivity are desired. Aluminum-selective chelation might be achieved by targeted chelator distribution or by the use of adjuvants with the chelator. The ability of carboxylic acids to facilitate Al elimination, under specific conditions, warrants further study. Desferrioxamine does not produce significant biliary Al excretion. A chelator with this property may be useful in ESRD patients. The necessity for an Al chelator to distribute extravascularly to be effective is unknown and should be determined to guide the selection of alternatives to DFO. The lack of oral efficacy and occasional side effects of DFO encourage identification of orally effective, safer Al chelators. The bidentate 3-hydroxypyridin-4-ones are currently the most encouraging alternatives to DFO. They have been shown to increase urinary Al excretion in rats and rabbits, but to have toxicity comparable to, or greater than, DFO. Their toxicity may relate to incomplete metal complexation. The ability of orally effective chelators to increase absorption of chelated metal from the gastrointestinal (Gl) tract needs to be evaluated. Orally effective, safe Al chelators would be of benefit to peritoneal dialysis patients and those with neurodegenerative disorders, if Al chelation therapy is indicated. The reduction of Alzheimer's disease (AD) progression and the reversal of Al-induced behavioral deficits and neurofibrillary tangles by DFO encourage further study of Al chelation therapy for selected neurodegenerative disorders.

Aluminum↗
PubMed1996

Sociotropy, autonomy, stress, and depression in Cushing syndrome.

Cognitive theory ascribes nonendogenous depression to latent dysfunctional beliefs activated by stressors impinging upon core values (e.g., rejection for a sociotropic person). To address ambiguities in past tests of the theory, this study measured personality (Sociotropy-Autonomy Scale) and recent stressors (Life Experience Survey and Hassles Scale) among 14 Cushing syndrome patients and 12 controls. Patients scored nonsignificantly higher in sociotropy, and sociotropy correlated positively with depression among patients. Because depression in Cushing syndrome presumably results from biological dysfunction rather than from the interaction of personality and relevant stressors, these results imply that sociotropy may be a consequence of depression as opposed to a contributory cause. There was no congruence between personality and types of stressors reported, which suggest that mood-dependent recall does not account for past evidence of congruence.

Adult↗
PubMed1995

Methyldopa kinetics before and after ingestion of methyldopa for eight weeks.

Methyldopa urine and plasma levels and urine metabolite levels were assessed following intravenous (IV) and oral (PO) methyldopa before, and after ingestion of methyldopa (500 mg) daily for eight weeks. There was no increase in (estimated) methyldopa absorption (8.4%) or renal clearance (PO 13.9%, IV 2.33%) after the eight weeks of methyldopa ingestion. However, the initial methyldopa absorption and renal clearance values in this study were higher than that in previous studies. There was an inverse relation between the initial methyldopa absorption and the change in absorption (r - 0.605) and between the initial methyldopa renal clearance and the change in renal clearance (PO r -0.874, IV r -0.891). Overall, this study did not confirm our previous studies showing induction of methyldopa absorption and renal clearance, possibly due to prior up regulation of transporter function. Consistent with methyldopa inducing drug transporters, those with low initial absorption and renal clearance values had the greatest increases.

Absorption↗
PubMed1995

Evidence-based recommendations for the clinical use of recombinant human erythropoietin.

In an era of increasing scrutiny regarding use of health care resources, it is critical that physicians have rational, evidence-based guidelines for treatment decisions. This review of more than 200 published papers constitutes a comprehensive approach to evaluating the current evidence regarding the clinical use of recombinant human erythropoietin therapy in renal failure patients. After this review, specific recommendations are provided regarding who should receive r-HuEPO; what the target hemoglobin should be; the best route of administration of r-HuEPO; how iron status should be evaluated and managed; and monitoring and follow-up of patients taking r-HuEPO. Throughout the article, areas for important future research are also identified.

Anemia↗
PubMed1993

Post-transplant conversion from cyclosporin to azathioprine: effect on cardiovascular risk profile.

The benefits of long-term cyclosporin (CyA) therapy are not yet established and must be weighed against its toxicity. We studied cardiovascular risk factors in 25 patients who received a kidney transplant between 1985 and 1989 and in whom CyA was discontinued. The protocol for discontinuing CyA involved starting azathioprine (Aza) and then weaning CyA over 6 weeks without changing the prednisone dose. Parameters collected from the patients' charts 3 months before (pre) and 3 months after conversion (post) and at the most current follow-up (cur) included serum creatinine, cholesterol, blood pressure, and anti-hypertensive medication. The severity of the hypertension was graded, based on a hypertension index reflecting the nature and dose of the anti-hypertensive medication. Of the 25 patients in whom CyA was discontinued, 2 experienced a rejection episode during conversion and were switched back to CyA; 1 patient had a rejection episode after conversion but remained on Aza. Converted patients demonstrated improved renal function (1/Cr pre 0.69 +/- 0.20, post 0.84 +/- 0.23, P < 0.05), lower serum cholesterol levels (pre 6.8 +/- 1.0, post 5.8 +/- 1.2, P < 0.05), lower mean arterial pressure (pre 111 +/- 14, post 102 +/- 8, P < 0.05) and a lower hypertension index (pre 2.45 +/- 2.77, cur 1.62 +/- 1.70, P < 0.05). Although conversion may carry some risk of acute rejection, it improves graft function and the cardiovascular risk profile significantly.

Adult↗
PubMed1992

Aluminum absorption and excretion following sucralfate therapy in chronic renal insufficiency.

PURPOSE: To measure serum aluminum levels and urinary aluminum excretion in patients with chronic renal insufficiency (CRF) receiving therapeutic doses of sucralfate. PATIENTS: Six patients with CRF were enrolled in the study. Creatinine clearances ranged from 0.2 to 0.9 mL/second (mean +/- SD 0.40 +/- 0.25 mL/second). Seven subjects with normal renal function were also studied. METHODS: Each subject received sucralfate 1 g four times daily for 21 days. Serum and urine samples (serum only) were collected on baseline and on Days 2, (3), 8, 15, 22, (23, 24), 29, and 36. Samples were assayed by graphite furnace atomic absorption spectrophotometry. RESULTS: In CRF, serum aluminum levels (mumol/L) increased by Day 2 and remained elevated to Day 24. Urinary aluminum excretion (mumol/day) was elevated throughout the study. The elimination half-life of serum aluminum after therapeutic dosing of sucralfate was 13.1 +/- 3.1 days. In subjects with normal renal function, baseline serum aluminum levels were similar to those in CRF (0.12 +/- 0.12 versus 0.11 +/- 0.12 mumol/L), but serum aluminum levels were higher at the end of the study in CRF (Day 22, 0.24 +/- 0.17 versus 0.83 +/- 0.48 mumol/L). CONCLUSIONS: After therapeutic doses of sucralfate, significant elevations of serum aluminum levels occurred in CRF. Serum aluminum levels were higher in patients with CRF than in normal subjects. Long courses of sucralfate should be used with caution or avoided in CRF.

Aluminum↗
PubMed1992

Prolonged hemodialysis in methanol intoxication.

Methanol poisoning may be treated conservatively by inducing a diuresis and administering ethanol to halt the metabolism of methanol to more toxic metabolites. In severe intoxications, hemodialysis may be necessary to remove the toxins and limit the metabolic disturbances. The duration of dialysis needed to achieve this is unclear. A case report of a severe methanol poisoning is reported which required 21 hours of hemodialysis to bring the serum methanol levels down to a nontoxic level.

Adult↗
PubMed1991

Plasma sodium-potassium ATPase inhibition activity in low- and normal-renin hypertension.

Thirty-seven subjects with low- and normal-renin hypertension (plasma renin activity less than 0.45 ng/L/sec on a 100 mmol Na diet) were studied on a 10 and 100 mmol sodium diet (100 mmol K and 25 mmol Ca) to examine the effect of varied sodium intake on plasma Na,K-ATPase inhibitory activity (NKAIA) (% inhibition). On the 10 mmol Na diet, plasma NKAIA correlated with mean arterial pressure (MAP) (r = 0.384, P = .019). On the 100 mmol Na diet, plasma NKAIA correlated with daily urinary sodium excretion (r = 0.384, P = .019). With the increase in sodium intake, the mean change in MAP was 0.5 +/- 7.8 mm Hg (range -12.7 to 16.3) and the mean change in plasma NKAIA was -4.2 +/- 11.2% inhibition (range -37.5 to 16). The change in MAP was correlated to the change in plasma NKAIA (r = 0.384, P = .019). Plasma NKAIA is related to mean arterial pressure or urinary sodium excretion depending on the dietary sodium intake, and is related to sodium-induced changes in MAP in low and normal renin hypertensive patients.

Adult↗
PubMed1991

Showcasing a profession: getting nursing on the newsstand.

Interacting with the media is a method of showcasing the nursing profession. Clinical nurse specialists (CNSs) have a variety of opportunities available for these interactions: appearing on television, participating in a radio program or writing to the media. A survey completed by the authors indicated that CNSs had many media interactions, yet overall, only 17% of all nurses surveyed used writing. This paper begins by discussing where to publish and how to prepare and target the audience. General and specific guidelines for publishing feature articles, health tips, letters to the editor, and other publishing possibilities are presented.

Humans↗