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Biomedical subjects

G Darling

Publications and source records attributed to G Darling.

9 recordsLinked to original sources
PubMed2006

The effect of reflux and bile acid aspiration on the lung allograft and its surfactant and innate immunity molecules SP-A and SP-D.

Gastro-esophageal reflux and related pulmonary bile acid aspiration were prospectively investigated as possible contributors to postlung transplant bronchiolitis obliterans syndrome (BOS). We also studied the impact of aspiration on pulmonary surfactant collectin proteins SP-A and SP-D and on surfactant phospholipids--all important components of innate immunity in the lung. Proximal and distal esophageal 24-h pH testing and broncho-alveolar lavage fluid (BALF) bile acid assays were performed prospectively at 3-month posttransplant in 50 patients. BALF was also assayed for SP-A, SP-D and phospholipids expressed as ratio to total lipids: phosphatidylcholine; dipalmitoylphosphatidylcholine; phosphatidylglycerol (PG); phosphatidylinositol; sphingomyelin (SM) and lysophosphatidylcholine. Actuarial freedom from BOS was assessed. Freedom from BOS was reduced in patients with abnormal (proximal and/or distal) esophageal pH findings or BALF bile acids (Log-rank Mantel-Cox p < 0.05). Abnormal pH findings were observed in 72% (8 of 11) of patients with bile acids detected within the BALF. BALF with high levels of bile acids also had significantly lower SP-A, SP-D, dipalmitoylphosphatidylcholine; PG and higher SM levels (Mann-Whitney, p < 0.05). Duodeno-gastro-esophageal reflux and consequent aspiration is a risk factor for the development of BOS postlung transplant. Bile acid aspiration is associated with impaired lung allograft innate immunity manifest by reduced surfactant collectins and altered phospholipids.

Bile Acids and Salts↗
PubMed2005

Endometrial and vaginal effects of low-dose estradiol delivered by vaginal ring or vaginal tablet.

AIMS: The major aims of the study were to compare the safety of a continuous low-dose estradiol-releasing vaginal ring (ESTring) to that of a vaginal estradiol tablet (Vagifem) on the endometrium and the relief of subjective symptoms and signs of urogenital estrogen deficiency. Quality of life and acceptability of treatment delivery were also assessed. STUDY DESIGN: A prospective, randomized study in which women were assigned in a 2:1 ratio to ESTring and Vagifem and followed for 12 months. The primary endpoint was endometrial safety, based on the results of ultrasound measurement of endometrial thickness and a progestogen challenge test at baseline and week 48. Efficacy was determined by subjective assessment of urogenital estrogen deficiency symptoms at baseline and weeks 3, 12, 24, 36 and 48 and assessment of signs of vaginal epithelial atrophy by the clinician at baseline, 12 and 48 weeks. In addition, pelvic floor strength, vaginal cytological evaluation and pH, bacteruria and patient acceptability were assessed. Quality of life was assessed using a menopause-specific quality-of-life questionnaire and a 2-day bladder diary at baseline and 12 and 48 weeks. The comparability of the two groups was assessed using ANOVA, chi2 or Fisher's exact tests. RESULTS: A total of 126 women were randomized to ESTring and 59 to Vagifem. There was no statistical difference between the groups in the alleviation of symptoms and signs of urogenital estrogen deficiency. Maturation indices increased in both groups, from generally atrophic at baseline to proliferative or highly proliferative at 48 weeks. After 48 weeks of treatment, there was no statistically significant difference in endometrial thickness between the two groups. A statistically smaller proportion of bleeding/spotting occurred in the ESTring group (n = 0) compared to the Vagifem users (n = 4). Estradiol and total estrone serum levels increased during treatment in both groups but remained within the normal postmenopausal range. General health status in both groups was unchanged but the urogenital component of health burden was significantly improved in both groups. Bladder diary variables showed no differences between treatment groups. CONCLUSION: Equivalent endometrial safety and efficacy in the relief of the symptoms and signs of urogenital estrogen deficiency were demonstrated for the 12 months' use of a low-dose estradiol-releasing vaginal ring and a vaginal estradiol tablet.

Administration, Intravaginal↗
PubMed2001

Breast disease and undergraduate medical education: a randomized trial to assess the effect of a home study module on medical student performance.

BACKGROUND: This study sought to demonstrate the effectiveness of a home study module (HSM) on student performance at a large urban medical school. METHOD: Second-year students were randomized to receive: 1) a HSM in addition to regular teaching of clinical breast examination or, 2) the regular teaching alone. The HSM included adult learning principles, problem-based learning, and practice guidelines. Students completed a pretest, a post-test, and course evaluation. The pre- and post-tests examined students' knowledge and comfort levels. RESULTS: Of 176 students, 136 agreed to participate and 127 completed both pre- and post-tests. Baseline pretest indicated no significant difference between the intervention and control groups. Post-test showed that students receiving the HSM gained significantly more knowledge than had the control group, and their comfort levels shifted nonsignificantly more. Student evaluations indicated perceived value of the HSM. INTERPRETATION: Student performance can be enhanced and comfort levels increased by providing a critical core of knowledge in the form of a HSM. This approach may be applicable to other important subjects.

Breast Diseases↗
PubMed1997

Adjuvant radiotherapy and chemotherapy for stage II or IIIA non-small-cell lung cancer after complete resection. Provincial Lung Cancer Disease Site Group.

GUIDELINE QUESTIONS: 1) Does the use of postoperative, adjuvant radiotherapy or chemotherapy, alone or in combination, improve survival rates among patients with completely resected, pathologically confirmed stage II or IIIA non-small-cell lung cancer (NSCLC)? 2) Does the use of radiotherapy reduce the risk of local recurrence among patients with completely resected stage II or IIIA NSCLC? OBJECTIVE: To make recommendations about the use of postoperative adjuvant radiotherapy and chemotherapy in the treatment of patients with completely resected stage II or IIIA NSCLC. OUTCOMES: Overall survival and disease-free survival are the primary outcomes of interest. A secondary outcome of interest is local disease control. PERSPECTIVES (VALUES): Evidence was collected and reviewed by 4 members of the Lung Cancer Disease Site Group (Lung Cancer DSG) of the Cancer Care Ontario Practice Guidelines Initiative. The evidence-based recommendation resulting from this review was approved by the Lung Cancer DSG, which comprises medical oncologists, radiation oncologists, pathologists, surgeons and a medical sociologist. A community representative was present at 1 meeting during which the recommendation was discussed. QUALITY OF EVIDENCE: One meta-analysis and 22 randomized controlled trials (RCTs) were published between 1962 and 1996. The RCTs compared surgery plus radiotherapy with surgery alone; surgery plus adjuvant chemotherapy with surgery alone; surgery plus radiotherapy with surgery plus both chemotherapy and radiotherapy. Many studies included patients with stage IIIB NSCLC; some included patients with incompletely resected stage I NSCLC or with small cell lung cancer (maximum 10%). Older studies used chemotherapy or radiation that would now be considered inferior according to current standards of practice. BENEFITS: There was no survival benefit with adjuvant radiotherapy alone, although 3 RCTs reported a reduction in the rate of local recurrence among patients treated with adjuvant radiotherapy. The meta-analysis showed that postoperative, cisplatin-based chemotherapy alone reduced the relative risk of death by 13% (hazard ratio [HR] 0.87, 95% confidence interval [CI] 0.74 to 1.02); in combination with radiotherapy it resulted in a 6% reduction in the relative risk of death (HR 0.94, 95% CI 0.79 to 1.11). HARMS: Postoperative adjuvant chemotherapy with alkylating agents was found in the meta-analysis to increase the relative risk of death by 15%. A study involving prolonged adjuvant chemotherapy (busulfan or cytoxan daily for 2 years) reported that 4 of 726 patients had hematologic malignancies. In 1 study, only 53% of patients received all 4 cycles of chemotherapy with cyclophosphamide-doxorubicin-cisplatin (CAP); in another, 22% of patients refused therapy with CAP because of nausea and vomiting. PRACTICE GUIDELINE: There is evidence from RCTs that postoperative radiotherapy reduces rates of local recurrence by 11% to 18% (or 1.6 to 19-fold) among patients with completely resected, pathologically confirmed stage II or IIIA NSCLC. Therefore, if the outcome of interest is a reduction in the frequency of local tumour recurrence, radiotherapy is recommended. However, there is no evidence of a survival benefit from postoperative radiotherapy alone. In a meta-analysis, postoperative chemotherapy with or without radiotherapy resulted in a slightly reduced (statistically nonsignificant) risk of death among patients with surgically resected stage II or IIIA NSCLC. The survival benefit was small and achieved only with chemotherapy regimens that produced substantial toxic effects and that are no longer used. Newer chemotherapy regimens are currently being evaluated as adjuvant therapy, but there is insufficient evidence of benefit at this time to recommend them. Therefore, if the outcome of interest is survival, there is insufficient evidence to recommend current chemotherapy regimens with or without radiotherapy as postoperative, adjuvant the

Carcinoma, Non-Small-Cell Lung↗
PubMed1992

Serum selenium levels in individuals on PKU diets.

Serum selenium levels in 73 patients with phenylketonuria were significantly lower than in controls. The phenylketonuric and hyperphenylalaninaemic individuals taking the non-supplemented amino acid mixture generally had lower levels: 36% were below the normal range as defined by our laboratory, compared with 19% in the supplemented group. The low levels were present even in those on diet, who had a greater phenylalanine tolerance--that is, a tolerance for more than 9 x 50 mg phenylalanine exchanges per day, in other words a higher intake of natural protein. Individuals on long-term synthetic diets may be at risk for selenium deficiency even on selenium supplements. In areas where the soil may be low in selenium, the deficiency may be aggravated. Long-term low levels may impair health but the required amount of selenium supplementation remains uncertain.

Adolescent↗
PubMed1990

Cachectic effects of recombinant human tumor necrosis factor in rats.

Treatment of rats with either intermittent bolus i.v. injections or continuous i.v. infusions of the same sublethal daily dose of tumor necrosis factor (TNF) results in decreased food intake and decreased nitrogen balance compared to saline-treated control rats. After 4 days of treatment, rats treated with intermittent bolus doses of TNF develop tolerance to the nutritional effects and consume normal amounts of food and have nitrogen balance similar to those of saline treated rats. Rats receiving the continuous infusion of TNF do not. Rats treated with both routes of TNF lose more weight than pair fed rats who eat the same mean amount as the continuous TNF treated group. In addition, 56% of rats receiving continuous infusion TNF die during the 8-day experimental period while rats receiving either intermittent bolus TNF or similar food intake (pair fed) do not. Body composition studies of rats that completed the 8 days of treatment indicate that rats receiving either continuous infusion or intermittent bolus TNF have increased percentages of body water and reduced percentages of body solid compared to saline treated control rats. Rats pair fed to the food intake of continuous TNF treated rats also had increased percentages of body water and reduced percentages of body solid, but changes were significantly less than those observed in continuous TNF infused rats. Continuous TNF infusion reduced total body nitrogen and potassium while pair feeding did not reduce potassium and reduced nitrogen to a lesser degree. Pair feeding and continuous TNF infusion reduced total body fat to a similar extent. Twice a day administration of TNF resulted in lesser changes in carcass water, solid, nitrogen, lipid, and potassium than continuous infusion of the same dose of TNF. The results indicate that continuous infusion of TNF can produce anorexia, weight loss, edema, loss of body protein, lipid and cell mass, and lethality which is markedly ameliorated with bolus doses of TNF. The findings are consistent with the hypothesis that slow continuous secretion of sublethal amounts of TNF may mediate cancer cachexia.

Animals↗
PubMed1990

Splenectomy in the management of systemic mast cell disease.

The records of 26 patients with systemic mast cell disease (SMCD) treated during the past decade at the National Institutes of Health were reviewed to determine the role of splenectomy in the management of SMCD. Seventeen (65%) patients had indolent SMCD, manifested primarily by urticaria pigmentosa and mast cell infiltration of the skin, bone marrow, or gastrointestinal tract. None of these patients underwent splenectomy. These patients required only symptomatic therapy. Nine (35%) patients, including those with associated hematologic disorders and those with a lymphoma-like illness termed lymphadenopathic mastocytosis with eosinophilia, had aggressive SMCD. Five of nine patients with aggressive SMCD underwent splenectomy. Of the five patients with splenectomy, three were alive at the time of this report, whereas none of the four who did not have a splenectomy was still alive. Length of survival without splenectomy was 26 months. With splenectomy, length of survival at the time of this report was 34 months. Patients without splenectomy died of bleeding caused by severe thrombocytopenia. Patients with splenectomy appeared better able to tolerate chemotherapy. We thus conclude that while splenectomy is of no value in the management of indolent mastocytosis, it should be considered in patients with aggressive SMCD.

Adult↗
PubMed1989

Tumor necrosis factor: immune endocrine interaction.

Tumor necrosis factor (TNF), a peptide produced by macrophages in response to endotoxin, has been implicated as a mediator of septic shock. This study examined the effects of injections of recombinant (r) human TNF on circulating levels of metabolic substrates and hormones in conscious, unrestrained rats and the effects of TNF on cortisol secretion from human adrenocortical cells in vitro. Sublethal doses of rTNF--doses that did not produce hemodynamic changes in previous work--produced rapid (1 hour), significant increases in blood levels of glucose, lactate, and triglycerides and decreases in plasma levels of branched chain amino acids. Plasma levels of glucagon, corticosterone, ACTH, norepinephrine, and dihydroxyphenylglycol were also increased significantly. Incubation of adrenocortical cells with either 0.15 or 1.5 micrograms of rTNF increased cortisol secretion to the same extent as did 10(-10) mol/L ACTH. Administration of TNF produces a variety of metabolic and neuroendocrine effects including stimulation of anterior pituitary, adrenal cortical, and pancreatic secretion, and sympathoneural activation. These changes, and the in vitro results, are consistent with the view that immune cells can interact with endocrine cells through release of TNF.

Adrenocorticotropic Hormone↗