Modeling the in vitro intrinsic clearance of the slowly metabolized compound tolbutamide determined in sandwich-cultured rat hepatocytes.

An alternative approach is introduced in determining the in vitro intrinsic clearance of slowly metabolized compounds. The longterm sandwich rat hepatocyte culture was exploited, allowing for sufficient substrate depletion to obtain a reliable clearance estimation; in its physiology, it resembles the in vivo liver, thus allowing in vivo extrapolation of the in vitro clearance value. Substrate depletion of tolbutamide and the formation of its metabolites hydroxytolbutamide and carboxytolbutamide were measured in the medium and sandwich layer. Depletion data from the medium were fitted to a mathematical model incorporating system-dependent parameters (diffusion, protein binding, and partitioning) to calculate the hepatocytes' intrinsic clearance. Based on the decrease of the parent compound in the medium, a specific intrinsic clearance value, i.e., clearance per unit of volume of hepatocytes, of 0.085 min(-1) was fitted. This value was in accordance with in vivo and in vitro values from the literature. The model was verified with substrate depletion data from the sandwich layer. Data on metabolite formation showed an incomplete mass balance. A radiochemical experiment revealed the presence of three additional metabolites. These metabolites were analyzed by liquid chromatography-mass spectometry. One was identified as p-tolysulfonylurea. The structure of the other two needs to be elucidated. After the addition of these compounds to the metabolic pattern, the mass balance was completed. The in vitro clearance value was incorporated in a physiologically based pharmacokinetic literature model of tolbutamide that accurately describes the plasma concentration. The approach used in this study successfully predicts the intrinsic clearance of tolbutamide. In addition, the sandwich rat hepatocyte culture also proves to be useful in the identification of metabolic pathways.     

Smoking decreases the level of circulating CD34+ progenitor cells in young healthy women - a pilot study

Background

Decreased levels of circulating bone marrow-derived progenitor cells have been associated with risk factors and cardiovascular diseases. Smoking is the most important modifiable risk factor for atherosclerosis in young women. The aim of this pilot study was to assess in healthy premenopausal women without other risk factors for cardiovascular disease the influence of nicotine abuse on the number of circulating progenitor cells in relation to endothelial function.

Methods

The number of endothelial progenitor cells, measured as colony-forming units in a cell-culture assay (EPC-CFU) and the number of circulating CD34 + and CD34 +/CD133 + cells, measured by flow cytometry, was estimated in 32 women at the menstrual phase of the menstrual cycle. In addition, flow-mediated dilation (FMD) was assessed as a marker for vascular function. In a subgroup of these women (n = 20), progenitor cells were also investigated at the mid-follicular and luteal phases of the menstrual cycle.

Results

Compared to non-smokers, the abundance of circulating CD34 + cells was significantly lower in smoking women in the menstrual, mid-luteal, and mid-follicular phases of the menstrual cycle. The number of CD34 + progenitor cells was revealed to have significant positive correlation with FMD in young healthy women, whereas CD34 +/CD133 + progenitor cells and EPC-CFU showed no significant correlation.

Conclusion

The number of CD34 + progenitor cells positively correlates with FMD in young healthy women and is decreased by smoking.     

Consumption of Dietary Fiber with Different Physicochemical Properties during Late Pregnancy Alters the Gut Microbiota and Relieves Constipation in Sow Model

Constipation is a common problem in sows and women during late pregnancy. Dietary fiber has potential in the regulation of intestinal microbiota, thereby promoting intestinal motility and reducing constipation. However, the effects of fibers with different physicochemical properties on intestinal microbe and constipation during late pregnancy have not been fully explored. In this study, a total of 80 sows were randomly allocated to control and one of three dietary fiber treatments from day 85 of gestation to delivery: LIG (lignocellulose), PRS (resistant starch), and KON (konjaku flour). Results showed that the defecation frequency and fecal consistency scores were highest in PRS. PRS and KON significantly increased the level of gut motility regulatory factors, 5-hydroxytryptamine (5-HT), motilin (MTL), and acetylcholinesterase (AChE) in serum. Moreover, PRS and KON promoted the IL-10 level and reduced the TNF-α level in serum. Furthermore, maternal PRS and KON supplementation significantly reduced the number of stillborn piglets. Microbial sequencing analysis showed that PRS and KON increased short-chain fatty acids (SCFAs)-producing genera Bacteroides and Parabacteroides and decreased the abundance of endotoxin-producing bacteria Desulfovibrio and Oscillibacter in feces. Moreover, the relative abundance of Turicibacter and the fecal butyrate concentration in PRS were the highest. Correlation analysis further revealed that the defecation frequency and serum 5-HT were positively correlated with Turicibacter and butyrate. In conclusion, PRS is the best fiber source for promoting gut motility, which was associated with increased levels of 5-HT under specific bacteria Turicibacter and butyrate stimulation, thereby relieving constipation. Our findings provide a reference for dietary fiber selection to improve intestinal motility in late pregnant mothers.     

Thumb-in-palm deformity with bowstringing; an unusual case

A spastic thumb can be abusively interpreted as a congenital trigger thumb. This case report describes the rare presentation of bowstringing in a spastic patient after earlier release of the first annular pulley. It is important to recognize bowstringing because of therapeutical consequences. Level of Evidence: Level V, diagnostic study.     

Effect of Spironolactone on Atrial Fibrillation in Patients with Heart Failure with Preserved Ejection Fraction: Post-Hoc Analysis of the Randomized,Placebo-Controlled TOPCAT Trial

Mineralocorticoid receptor antagonists (MRAs) reduce the risk of atrial fibrillation (AF) in patients with heart failure (HF) and a reduced ejection fraction. The efficacy of MRAs for AF prevention in patients with HF and a preserved ejection fraction (HFpEF) is unclear. We performed a secondary analysis of a randomized placebo-controlled trial to determine the efficacy of spironolactone in reducing new-onset AF and recurrence of AF in 2733 patients with symptomatic HFpEF. Patients with and without prevalent AF at baseline were included, and those with permanent AF were excluded. Patients were randomized 1:1 to spironolactone or placebo. The risk of new-onset AF or the recurrence of AF was quantified using hazard ratios (HRs) with corresponding 95% confidence intervals (CIs). At baseline, 2228 (64.7%) patients had no history of AF (spironolactone, n = 1111; placebo, n = 1117), whereas 505 (18.4%) patients had prevalent AF (spironolactone, n = 260; placebo, n = 245). During a median follow-up of 3.1 years (interquartile range [IQR] 2.0–4.9), the incidence of new-onset AF was similar in both treatment arms: spironolactone 5.2% (n = 58) versus placebo 4.4% (n = 49); p = 0.41. The risk of new-onset AF was similar in both treatment arms: HR 1.19; 95% CI 0.81–1.74; p = 0.38. AF recurrence was also similar in both treatment arms during a median follow-up of 3.3 years (IQR 1.9–4.7): spironolactone 11.5% (n = 30) versus placebo 11.8% (n = 29); p = 1.00. The risk of recurrence of AF did not differ per treatment arm: HR 0.94; 95% CI 0.57–1.58; p = 0.83. Spironolactone does not reduce the risk of new-onset AF or AF recurrence in patients with HFpEF. This is in contrast to results in cohorts of patients with HF and a reduced ejection fraction. ClinicalTrials.gov identifier no. NCT00094302 (TOPCAT).     

The effect of growth hormone administration in growth hormone deficient adults on bone, protein, carbohydrate and lipid homeostasis, as well as on body composition

OBJECTIVE: The effect on bone, protein, carbohydrate and lipid homeostasis as well as body composition of the administration of growth hormone to adult patients with growth hormone deficiency was studied. DESIGN: Growth hormone was administered at a dose of 25 micrograms/kg/day with a maximum of 1.48 mg (4 IU) a day, for 6 months in eight adults. Studies were done before the start and at 1, 3 and 6 months during therapy, as well as 3 months after treatment had been stopped. RESULTS: Subjective well-being as assessed by a short psychological tests showed an improvement in six and no change in two patients. Body composition, as assessed by body impedance assessment and D2O dilution, both showed an increase in lean body mass of 4 kg (5% of body weight), accompanied by a decrease in mean fat mass of 3 kg. Nitrogen turnover studies showed a transient increase in fed state nitrogen balance due to an increase in the rate of protein synthesis, which exceeded a smaller increase in the protein degradation rate. Growth hormone treatment did not affect the circulating levels of 25(OH)-vitD or PTH 1-84, while 1,25(OH)2-vitD had significantly increased after 6 months, as well as 3 months after treatment ended. Osteocalcin, procollagen I levels, as well as 24-hour urinary excretion of hydroxyproline and calcium rose during growth hormone administration but subsequently decreased rapidly after administration had been stopped, while the increase in alkaline phosphatase persisted. This increase in markers of both bone resorption and bone formation indicates an activation of bone remodelling, but this was not reflected by an increase in bone density. Glucose levels, measured before and during a normal breakfast, increased during growth hormone treatment, but serum insulin levels did not. Total cholesterol levels decreased by 0.5 mmol/l. Levels of T4 and free T4 as well as rT3 decreased, while T3 increased during growth hormone treatment. CONCLUSION: Therapy with growth hormone for 6 months in a dose varying between 6 and 25 micrograms/kg/day increased lean body mass and decreased fat mass. The sense of general well-being improved in most patients. Furthermore, growth hormone treatment increased bone turnover without a measurable increase in bone density, caused some minor changes in lipid and carbohydrate metabolism, and increased the metabolism of thyroxine to T3.     

More differences between HNPCC-related and sporadic carcinomas from the endometrium as compared to the colon

PURPOSE: Recognition of hereditary nonpolyposis colorectal cancer (HNPCC)-related endometrial carcinoma from sporadic carcinoma by histologic features as compared with colonic cases. STUDY DESIGN: Case-control study. METHODS AND MATERIALS: From the files of the Nijmegen Hereditary Cancer Clinic, HNPCC-related (n = 6) endometrial and colorectal (n = 18) carcinomas were selected. For every HNPCC-related tumor, 2 sporadic control cases were included. The tumors were evaluated for the following 7 pathologic features: tumor differentiation, T-stage, growth pattern, presence of Crohn-like lymphoid reaction, mucinous differentiation, presence of lymphangioinvasive growth, and the amount of tumor-infiltrating lymphocytes. RESULTS: HNPCC-related endometrial carcinomas were significantly more often poorly differentiated (83% versus 27%), more often showed the presence of a Crohn-like lymphoid reaction (100% versus 13%) and lymphangioinvasive growth (67% versus 0%), and high number of tumor-infiltrating lymphocytes were more often present (100% versus 36%) compared with sporadic endometrial carcinomas. The differences between HNPCC and sporadic colorectal cancer specimens were less discriminating. CONCLUSIONS: HNPCC-related endometrial carcinomas are characterized by poor differentiation, more frequent Crohn-like lymphoid reaction, lymphangioinvasive growth and more tumor-infiltrating lymphocytes. These features therefore might form the basis for selecting patients for counseling in a hereditary cancer clinic or testing for microsatellite instability or mutation analysis of mismatch repair genes, especially when they are of relatively young age.