Biomedical subjects

David Guthrie

Publications and source records attributed to David Guthrie.

6 recordsLinked to original sources

PubMed2026

Higher versus Routine Intraoperative Blood Pressure Targets in Noncardiac Surgery: A Systematic Review and Meta-analysis with Trial Sequential Analysis of Randomized Trials.

BACKGROUND: Observational studies consistently link intraoperative hypotension to adverse postoperative outcomes, leading guidelines to recommend maintaining mean arterial pressure 60 to 65 mmHg or greater during noncardiac surgery. Whether targeting higher intraoperative blood pressure values improves clinical outcomes remains uncertain. METHODS: The authors conducted a Preferred Reporting Items for Systematic Reviews and Meta-analyses-guided search on PubMed, Cochrane Central Register of Controlled Trials, Scopus, and Embase from inception to April 2026. Randomized trials comparing higher intraoperative blood pressure targets, either as fixed absolute thresholds or personalized to preoperative baseline, versus routine blood pressure management in adults undergoing elective noncardiac surgery with general anesthesia were included. Outcomes included in-hospital or 30-day mortality, postoperative delirium, acute kidney injury (AKI), 30-day major cardiovascular events, acute myocardial injury, stroke, length of stay, and intraoperative hypotension. RESULTS: Fifteen trials (15,603 patients) were included. Higher targets did not reduce AKI (risk ratio [RR], 0.95; 95% CI, 0.85 to 1.06; P = 0.36; I 2 = 16%) or acute myocardial injury (RR, 1.02; 95% CI, 0.94 to 1.12; P = 0.59; I 2 = 0%) compared with routine targets, with firm evidence from trial sequential analysis. Higher targets were associated with a significant reduction in postoperative delirium (RR, 0.73; 95% CI, 0.54 to 0.98; P = 0.04; I 2 = 26%), although trial sequential analysis indicated the cumulative evidence remained insufficient to draw firm conclusions. No significant effect was observed on in-hospital or 30-day mortality (RR, 1.00; 95% CI, 0.75 to 1.34; P = 1.00; I 2 = 0%); evidence on 30-day major cardiovascular events, stroke, and length of stay was similarly insufficient to draw firm conclusions. CONCLUSION: In adults undergoing elective noncardiac surgery, targeting higher intraoperative blood pressure values does not improve major postoperative outcomes compared with routine management. A potential reduction in postoperative delirium warrants confirmation in adequately powered trials.

Humans↗

PubMed2003

Synthesis and reactions of fluorous carbobenzyloxy (FCbz) derivatives of alpha-amino acids.

Fluorous carbobenzyloxy ((F)Cbz) reagents RfCH(2)CH(2)C(6)H(4)CH(2)OC(O)OSu (where Su is succinimidoyl and Rf is C(6)F(13) and C(8)F(17)) have been used to make (F)Cbz derivatives of 18 of the 20 natural amino acids. The potential utility of this new family of reagents in both standard fluorous synthesis with spe separation and fluorous quasiracemic synthesis is illustrated with representative reactions of the (F)Cbz-Phe derivatives.

Amino Acids↗

PubMed2003

International Collaborative Ovarian Neoplasm trial 1: a randomized trial of adjuvant chemotherapy in women with early-stage ovarian cancer.

BACKGROUND: The question of whether platinum-based adjuvant chemotherapy can improve outcomes in patients with early-stage epithelial ovarian cancer is an important one. We carried out a multicenter, open randomized trial to determine whether adjuvant chemotherapy would improve overall survival and prolong recurrence-free survival in women with early-stage epithelial ovarian cancer. METHODS: Between August 1991 and January 2000, 477 patients in 84 centers in five countries were randomly assigned to receive either adjuvant chemotherapy immediately following surgery (n = 241) or no adjuvant chemotherapy until clinically indicated (n = 236). Kaplan-Meier curves of overall survival and recurrence-free survival were compared using the Mantel-Cox version of the log-rank test. All statistical tests were two-sided. RESULTS: Women who received adjuvant chemotherapy had better overall survival than women who did not (hazard ratio [HR] of 0.66, 95% confidence interval [CI] = 0.45 to 0.97; P =.03). These results translate into 5-year survival figures of 70% for women who did not receive adjuvant chemotherapy and 79% for women who did receive adjuvant chemotherapy, a difference of 9% (95% CI = 1% to 15%). Adjuvant chemotherapy also improved recurrence-free survival (HR = 0.65; 95% CI = 0.46 to 0.91; P =.01). These results translate into 5-year recurrence-free survival figures of 62% for women who did not receive adjuvant chemotherapy and 73% for women who did receive adjuvant chemotherapy, a difference of 11% (95% CI = 3% to 18%). CONCLUSION: These results suggest that platinum-based adjuvant chemotherapy improves survival and delays recurrence in patients with early-stage ovarian cancer.

Aged↗

PubMed2003

International Collaborative Ovarian Neoplasm trial 1 and Adjuvant ChemoTherapy In Ovarian Neoplasm trial: two parallel randomized phase III trials of adjuvant chemotherapy in patients with early-stage ovarian carcinoma.

BACKGROUND: Adjuvant chemotherapy has been suggested as a possible strategy to improve survival in women with early-stage ovarian cancer; however, all randomized studies to date have been too small to answer this question reliably. METHODS: We performed a preplanned combined analysis of two parallel randomized clinical trials (International Collaborative Ovarian Neoplasm 1 [ICON1] and Adjuvant ChemoTherapy In Ovarian Neoplasm [ACTION]) in early-stage ovarian cancer that compared platinum-based adjuvant chemotherapy with observation following surgery. Between November 1990 and January 2000, 925 patients (477 in ICON1 and 448 in ACTION) who had surgery for early-stage ovarian cancer were randomly assigned to receive platinum-based adjuvant chemotherapy (n = 465) or observation (n = 460) until chemotherapy was indicated. Kaplan-Meier analysis was used to compare overall and recurrence-free survival by treatment allocation. In subgroup analyses of pretreatment age, tumor stage, histologic cell type, and differentiation grade, the differences in relative size of effect were tested using a chi-square test for interaction or a chi-square test for trend. All tests of statistical significance were two-sided. RESULTS: After a median follow-up of over 4 years, 245 patients had died or had a recurrence (ICON1: 133, ACTION: 112). Overall survival at 5 years was 82% in the chemotherapy arm and 74% in the observation arm (difference = 8% [95% confidence interval (CI) = 2% to 12%]; hazard ratio [HR] = 0.67, 95% CI = 0.50 to 0.90; P =.008). Recurrence-free survival at 5 years was also better in the adjuvant chemotherapy arm than it was in the observation arm (76% versus 65%, difference = 11% [95% CI = 5% to 16%]; HR = 0.64, 95% CI = 0.50 to 0.82; P =.001). Subgroup analyses provided no evidence of a difference in the size of effect of chemotherapy on survival in any pretreatment subcategory. CONCLUSIONS: Platinum-based adjuvant chemotherapy improved overall survival and recurrence-free survival at 5 years in this combined group of patients with early-stage ovarian cancer defined by the inclusion criteria of the ICON1 and ACTION trials.

Aged↗

PubMed2003

Renal homeostasis of calcium.

Calcium is critical for many metabolic functions. While 99% of body calcium is found as part of the structure of bone and teeth, 1% found in plasma and body cells is crucial for such functions as blood clotting, nerve impulse conduction, and muscle contraction. The homeostasis of calcium is complex because the gastrointestinal tract, the bones, and the kidneys all affect calcium balance. This manuscript reviews the functions, homeostasis, and renal handling and regulation of calcium. The major sites of renal tubular reabsorption and the related cellular mechanisms are described.

Biological Transport↗

PubMedDate not supplied

Urinary concentration and dilution.

Water constitutes approximately 60% of the healthy adult human body. Water balance in the body is regulated by the kidneys, which excrete either concentrated or dilute urine in accordance with physiological needs. This article describes the mechanisms by which the kidneys vary water excretion independent of excretion of other physiological important substrates such as sodium, potassium, hydrogen, and urea. These mechanisms involve the loops of Henle, the distal tubules, the collecting ducts, and the vasa recta, and are under the control of vasopressin (antidiuretic hormone).

Aquaporins↗