Biomedical subjects

Kenneth Smith

Publications and source records attributed to Kenneth Smith.

22 records · Page 2Linked to original sources

PubMed2003

High serum YKL-40 levels in patients with primary breast cancer is related to short recurrence free survival.

YKL-40 is a growth factor for connective tissue cells and stimulates migration of endothelial cells. YKL-40 is secreted by cancer cells, and elevated serum YKL-40 in patients with metastatic breast cancer and colorectal cancer is associated with a poorer prognosis as compared to patients with normal serum YKL-40. In the present study we evaluated the associations of preoperative serum YKL-40 in 271 patients with primary breast cancer in relation to relapse-free survival and overall survival. The median follow-up time was 5.9 years. There were 77 relapses and 69 patients died. The median serum YKL-40 concentration in the patients was 57 microg/l (range 22-688 microg/l) and significantly elevated (p < 0.0001) compared to serum YKL-40 in healthy females. Nineteen percent of the patients had high serum YKL-40 (i.e., >95 percentile of healthy females). Patients with high serum YKL-40 had shorter relapse-free interval (hazard ratio (HR) = 1.77, 95% confidence interval (CI): 1.06-2.95, p = 0.028) and overall survival (HR = 1.78, 95% CI: 1.04-3.05, p = 0.036) than patients with normal serum YKL-40. Serum YKL-40 was higher (p = 0.005) in lymph node positive patients as compared to lymph node negative patients. Multivariate analysis including lymph node status, estrogen receptor status, tumor size, age, menstrual status and serum YKL-40 showed that serum YKL-40 was an independent prognostic variable of relapse-free survival (HR = 1.73, 95% CI: 1.03-2.91, p = 0.039). Our results show that serum YKL-40 in patients with primary breast cancer at time of operation is only elevated in a small group of patients, but these patients have a shorter recurrence free interval. Further studies are required to determine the biological function of YKL-40 in breast cancer.

Adipokines↗

PubMed2002

Creatine supplementation has no effect on human muscle protein turnover at rest in the postabsorptive or fed states.

Dietary creatine supplementation is associated with increases in muscle mass, but the mechanism is unknown. We tested the hypothesis that creatine supplementation enhanced myofibrillar protein synthesis (MPS) and diminished muscle protein breakdown (MPB) in the fed state. Six healthy men (26 +/- 7 yr, body mass index 22 +/- 4 kg/m(2)) were studied twice, 2-4 wk apart, before and after ingestion of creatine (21 g/day, 5 days). We carried out two sets of measurements within 5.5 h of both MPS (by incorporation of [1-(13)C]leucine in quadriceps muscle) and MPB (as dilution of [1-(13)C]leucine or [(2)H(5)]phenylalanine across the forearm); for the first 3 h, the subjects were postabsorptive but thereafter were fed orally (0.3 g maltodextrin and 0.083 g protein. kg body wt(-1) x h(-1)). Creatine supplementation increased muscle total creatine by approximately 30% (P < 0.01). Feeding had significant effects, doubling MPS (P < 0.001) and depressing MPB by approximately 40% (P < 0.026), but creatine had no effect on turnover in the postabsorptive or fed states. Thus any increase in muscle mass accompanying creatine supplementation must be associated with increased physical activity.

Adenosine Triphosphate↗

PubMed2002

Distinguishing the activities of 11beta-hydroxysteroid dehydrogenases in vivo using isotopically labeled cortisol.

The isozymes of 11beta-hydroxysteroid dehydrogenase (11betaHSDs) catalyze the interconversion of cortisol and cortisone. The type 2 dehydrogenase inactivates cortisol to cortisone, whereas the type 1 catalyzes predominantly the reverse reductive reaction. These reactions take place in different tissues, where they are subject to distinct regulation, and may be important in common pathologies. Current methods to determine the activities of these enzymes in vivo rely only on the balance between cortisol and cortisone, do not measure turnover, and cannot distinguish between the two reactions. We have investigated the use of [9,11,12,12-2H4]cortisol (d4F) to distinguish the dehydrogenase and reductase activities. On metabolism by dehydrogenation, d4F loses 11alpha- deuterium, forming trideuterated cortisone (d3E) and is regenerated by reduction to trideuterated cortisol (d3F). Healthy men (n = 6) participated in a randomized, double blind, cross-over study comparing oral placebo and the 11betaHSD inhibitor, carbenoxolone (100 mg every 8 h for 7 d). d4F and its metabolites were measured in plasma and urine during a steady state infusion. Inhibition of 11betaHSDs by carbenoxolone was measured by increased steady state concentrations of d4F (41 +/- 5.1 vs. 48 +/- 7.7 nM; P < 0.05) and a fall in the rate of appearance of d3F (P < 0.05). 11betaHSD1 reductase activity could be measured specifically as conversion of d3E to d3F (28 +/- 4.2 vs. 17 +/- 3.1 nM; P < 0.05), whereas 11betaHSD2 could be measured by initial rates of appearance of d3E or from urinary ratios of d4F/(d3E + d3F) (0.73 +/- 0.06 vs. 1.02 +/- 0.03; P < 0.05). This technique offers a significant advance in the methods available to measure turnover in 11betaHSDs and isozymes of 11betaHSDs in vivo in human studies, and this study confirms that carbenoxolone inhibits both isozymes of 11betaHSD.

11-beta-Hydroxysteroid Dehydrogenases↗

PubMed2002

Prognostic significance of soluble urokinase plasminogen activator receptor in serum and cytosol of tumor tissue from patients with primary breast cancer.

PURPOSE: The aim of the study was to evaluate the prognostic value of soluble urokinase plasminogen activator receptor (suPAR) in preoperatively obtained sera samples (s-suPAR) from breast cancer patients. EXPERIMENTAL DESIGN: suPAR levels were determined by the use of a kinetic ELISA in sera from 274 breast cancer patients and in tumor cytosols (c-suPAR) from 188 of these patients. In addition, s-suPAR levels were analyzed in 174 female blood donors. RESULTS: The mean s-suPAR level was 3.8 ng/ml (range, 1.6-9.2 ng/ml) in the patients and 3 ng/ml (range, 1.3-6.4 ng/ml) in the donors. The mean c-suPAR level was 0.55 ng/mg protein (range, 0.07-2.83 ng/mg protein). A weak but significant linear association was found between s-suPAR and age in the donors; thus, all of the s-suPAR levels were adjusted for this age dependency (aa-s-suPAR). The aa-s-suPAR levels were significantly increased in the patients as compared with the donors (P < 0.0001). No difference was found in aa-s-suPAR levels between the lymph node-positive and -negative patients (P = 0.27), and no correlation was seen between aa-s-suPAR and c-suPAR (sigma = 0.08; P = 0.71). During the follow-up period (5.9 years) 77 patients experienced a relapse and 69 died. aa-s-suPAR as a continuous variable was significantly associated with relapse-free survival [hazard ratio (HR), 1.4; 95% confidence interval (CI), 1.1-1.8; P = 0.003] and overall survival (HR, 1.6; 95% CI, 1.2-2.0; P < 0.0001). In multivariate Cox analysis including the classical prognostic parameters in breast cancer, continuous aa-s-suPAR was significantly associated with both relapse-free survival (HR, 1.4; 95% CI, 1.1-1.7; P = 0.001) and overall survival (HR, 1.4; 95% CI, 1.1-1.8; P = 0.002). In these analyses positive lymph nodes, tumor size >2 cm, and negative estrogen receptor content were also significantly associated with patient outcome. CONCLUSION: This study shows that high preoperative aa-s-suPAR levels are significantly associated with poor outcome for breast cancer patients independent of lymph node status, tumor size, and estrogen receptor status.

Adolescent↗