Revisiting left atrial volumetry by magnetic resonance imaging: the role of atrial shape and 3D angle between left ventricular and left atrial axis.

BACKGROUND: Accurate measurement of left atrial (LA) volumes is needed in cardiac diagnostics and the follow up of heart and valvular diseases. Geometrical assumptions with 2D methods for LA volume estimation contribute to volume misestimation. In this study, we test agreement of 3D and 2D methods of LA volume detection and explore contribution of 3D LA axis orientation and LA shape in introducing error in 2D methods by cardiovascular magnetic resonance imaging. METHODS: 30 patients with prior first-ever ischemic stroke and no known heart disease, and 30 healthy controls were enrolled (age 18-49) in a substudy of a prospective case-control study. All study subjects underwent cardiac magnetic resonance imaging and were pooled for this methodological study. LA volumes were calculated by biplane area-length method from both conventional long axis (LAVAL-LV) and LA long axis-oriented images (LAVAL-LA) and were compared to 3D segmented LA volume (LAVSAX) to assess accuracy of volume detection. 3D orientation of LA long axis to left ventricular (LV) long axis and to four-chamber plane were determined, and LA 3D sphericity indices were calculated to assess sources of error in LA volume calculation. Shapiro-Wilk test, Bland-Altman analysis, intraclass and Pearson correlation, and Spearman's rho were used for statistical analysis. RESULTS: Biases were - 9.9 mL (- 12.5 to - 7.2) for LAVAL-LV and 13.4 (10.0-16.9) for LAVAL-LA [mean difference to LAVSAX (95% confidence interval)]. End-diastolic LA long axis 3D deviation angle to LV long axis was 28.3 ± 6.2° [mean ± SD] and LA long axis 3D rotation angle to four-chamber plane 20.5 ± 18.0°. 3D orientation of LA axis or 3D sphericity were not correlated to error in LA volume calculation. CONCLUSIONS: Calculated LA volume accuracy did not improve by using LA long axis-oriented images for volume calculation in comparison to conventional method. We present novel data on LA axis orientation and a novel metric of LA sphericity and conclude that these measures cannot be utilized to assess error in LA volume calculation. TRIAL REGISTRATION: Main study Searching for Explanations for Cryptogenic Stroke in the Young: Revealing the Etiology, Triggers, and Outcome (SECRETO; NCT01934725) has been registered previously.

Toward a Consensus on Centralization in Surgery.

OBJECTIVES: To critically assess centralization policies for highly specialized surgeries in Europe and North America and propose recommendations. BACKGROUND/METHODS: Most countries are increasingly forced to maintain quality medicine at a reasonable cost. An all-inclusive perspective, including health care providers, payers, society as a whole and patients, has ubiquitously failed, arguably for different reasons in environments. This special article follows 3 aims: first, analyze health care policies for centralization in different countries, second, analyze how centralization strategies affect patient outcome and other aspects such as medical education and cost, and third, propose recommendations for centralization, which could apply across continents. RESULTS: Conflicting interests have led many countries to compromise for a health care system based on factors beyond best patient-oriented care. Centralization has been a common strategy, but modalities vary greatly among countries with no consensus on the minimal requirement for the number of procedures per center or per surgeon. Most national policies are either partially or not implemented. Data overwhelmingly indicate that concentration of complex care or procedures in specialized centers have positive impacts on quality of care and cost. Countries requiring lower threshold numbers for centralization, however, may cause inappropriate expansion of indications, as hospitals struggle to fulfill the criteria. Centralization requires adjustments in training and credentialing of general and specialized surgeons, and patient education. CONCLUSION/RECOMMENDATIONS: There is an obvious need in most areas for effective centralization. Unrestrained, purely "market driven" approaches are deleterious to patients and society. Centralization should not be based solely on minimal number of procedures, but rather on the multidisciplinary treatment of complex diseases including well-trained specialists available around the clock. Audited prospective database with monitoring of quality of care and cost are mandatory.

Thrombin generation in vitro and in vivo, and disturbed tissue factor regulation in patients with acute pancreatitis.

BACKGROUND: Being a central link between inflammation and coagulation, tissue factor (TF) and its inhibitor (TFPI) might be associated with the severity of acute pancreatitis (AP) and the development of organ failure (OF). METHODS: The study comprises 9 severe AP patients with OF and 24 reference patients (11 mild AP and 13 severe AP without OF). Plasma samples were collected on admission. TF-induced thrombin generation in plasma samples was studied using the thrombogram method. In vivo thrombin generation was estimated by prothrombin fragment F1+2. Free and total TFPI levels were measured. To evaluate coagulation status the activated partial thromboplastin time, prothrombin time, platelet count, D-dimer, fibrinogen, antithrombin (AT) 3 and protein C (PC) were determined. RESULTS: There was no significant difference in F1+2 levels between the patient groups. Patients with severe AP tended to show low platelet counts, PC and AT3 levels, and high D-dimer levels. In 11 patients the standard TF stimulation did not trigger thrombin generation in the thrombogram. All deaths occurred in these patients. Free TFPI levels and free/total TFPI ratios were significantly higher in these patients and in non-survivors. CONCLUSION: Failure of TF-initiated thrombin generation in the thrombogram assay explained by high levels of circulating free TFPI may be associated with OF and mortality in AP. and IAP.

The effect of core stability training on balance and mobility in ambulant individuals with multiple sclerosis: a multi-centre series of single case studies.

BACKGROUND: Core stability training is popular in the management of people with multiple sclerosis (MS); however, scientific evidence to support its effectiveness is scarce. OBJECTIVE: To explore the effectiveness of core stability training on balance and mobility. METHOD: A multi-centre series of eight single case studies was undertaken. Eight ambulant individuals with stable MS participated in 16 face-to-face core stability training sessions, delivered by a neurophysiotherapist, plus a daily home exercise programme. A range of outcomes were measured: 10-m timed walk, 12-item MS walking scale, timed get up and go, functional reach tests, timed single leg stance, visual analogue scales of two activities, and the Activities-specific Balance Confidence Scale. RESULTS: Visual analysis of trend, level and slope demonstrated improvement in five subjects (62%) in seven measures. This was confirmed by the two standard deviation band method of analysis for six measures. Analysis of group data (repeated measures within subjects analysis of variance) indicated significant improvement between baseline and intervention phases for timed walk (p = 0.019), MSWS-12 Scale (p = 0.041), forward (p = 0.015) and lateral reach (p = 0.012). In general, no further improvements were made following withdrawal of the intervention. CONCLUSIONS: This study provides preliminary evidence of the effectiveness of an 8-week core stability training programme in improving balance and mobility in ambulant people with MS. Variations in response to intervention are evident. Assessor-blinded randomized controlled studies are required to confirm these findings and determine patient characteristics which identify those who benefit most from this intervention.

A prospective diagnostic accuracy study of 18F-fluorodeoxyglucose positron emission tomography/computed tomography, multidetector row computed tomography, and magnetic resonance imaging in primary diagnosis and staging of pancreatic cancer.

OBJECTIVE: To prospectively compare the accuracy of combined positron emission tomography/computed tomography using F-fluorodeoxyglucose (FDG-PET/CT), multidetector row computed tomography (MDCT), and magnetic resonance imaging (MRI) in the evaluation of patients with suspected pancreatic malignancy. SUMMARY BACKGROUND DATA: FDG-PET/CT imaging is increasingly used for staging of pancreatic cancer. Preliminary data suggest a significant influence of FDG-PET/CT on treatment planning, although its role is still evolving. METHODS: Thirty-eight consecutive patients with suspicion of pancreatic malignancy were enrolled. Patients underwent a protocol including FDG-PET/CT, MDCT, and MRI combined with magnetic resonance cholangiopancreatography, all of which were blindly evaluated. The findings were confirmed macroscopically at operation and/or by histopathologic analysis (n = 29) or follow-up (n = 9). Results of TNM classification of different imaging methods were compared with clinical TNM classification. RESULTS: Pancreatic adenocarcinoma was diagnosed in 17 patients, neuroendocrine tumor in 3, mass-forming pancreatitis in 4, cystic lesion in 6, and fibrosis in 2. Six patients had a finding of a normal pancreas. The diagnostic accuracy of FDG-PET/CT for pancreatic malignancy was 89%, compared with 76% and 79% for MDCT and MRI, respectively. In the differential diagnosis of suspected malignant biliary stricture at endoscopic retrograde cholangiopancreaticography (n = 21), FDG-PET/CT had a positive predictive value of 92%. In 17 patients with advanced pancreatic adenocarcinoma, FDG-PET/CT had a sensitivity of 30% for N- and 88% for M-staging. Both MDCT and MRI had sensitivities of 30% for N- and 38% for M-staging. Furthermore, the clinical management of 10 patients (26%) was altered after FDG-PET/CT. CONCLUSION: FDG-PET/CT was more sensitive than conventional imaging in the diagnosis of both primary pancreatic adenocarcinoma and associated distant metastases. In contrast, the sensitivity of FDG-PET/CT was poor in detecting local lymph node metastasis, which would have been important for an assessment of resectability. We recommend the use of FDG-PET/CT in the evaluation of diagnostically challenging cases, especially in patients with biliary strictures without evidence of malignancy in conventional imaging.

Sexual experiences during the climacteric years: what do women think about it?

PURPOSE: To describe women's sexual experiences during the climacteric years. METHODS: The analysis was conducted using a theoretical-methodological perspective based on phenomenology. Data were obtained through a group interview method: the focus group. Participants were women attending a health education programme during the climacteric period. This programme was developed by the sexual and reproductive health services for the area of Barcelona (Spain). RESULTS: Reading and analysis of participants' discourse revealed four categories: the climacteric stage, a time for self-reassertion; the relative burden of biology; the journey through sexual life; and the importance of social/family factors as regards sexual experiences. CONCLUSIONS: In this study, social, family and structural factors had the greatest impact on sexual experience during this stage of life. The lack of independence with respect to parents, who have often moved into the family's residence, turns many of these women into informal carers. Tiredness, lack of intimacy and a reduced living space that is often shared with parents or grownup children are strong determinants as regards the free expression of sexuality.

Altered tissue repair in hevin-null mice: inhibition of fibroblast migration by a matricellular SPARC homolog.

Matricellular proteins such as hevin, secreted protein acidic and rich in cysteine, and thrombospondin-2 play an important role during tissue repair through their influence on fundamental cellular activities such as adhesion, migration, proliferation, and extracellular matrix synthesis/reorganization. We have investigated the role played by hevin during excisional and incisional cutaneous wound repair in hevin-null mice. Hevin-null animals both close and heal their skin wounds faster than wild-type animals, as evidenced by enhanced macrophage infiltration of wound beds at early time points, the earlier appearance of mature extracellular matrix, and the overall higher maturity score. In addition, fibrovascular invasion of polyvinyl alcohol sponges was more robust in hevin-null mice, a result indicating that differences in cell migration might underlie the observed alterations in wound repair. Experiments in vitro showed that hevin induced the deadhesion and inhibited the migration of primary dermal fibroblasts in a Rac-1-dependent manner. These findings indicate that the differences in wound repair between hevin-null and wild-type animals can be attributed in part to the deadhesive function of hevin and reduced cell migration within dermal wound beds in which this protein is expressed.

Tumor-associated macrophages (TAMs) as biomarkers for gastric cancer: A review.

Gastric adenocarcinoma is one of the most common types of cancer worldwide, with an incidence of a million new cases annually. In addition to having a high mortality rate due to often delayed detection and its poor response to cancer therapy, it also spreads aggressively. Inflammation has been shown to play a role in carcinogenesis. Consequently, macrophages are important in phagocytosis, antigen presenting and producing cytokines and growth factors. As a response to microenvironmental signals, they may polarize into tumor resisting M1 or tumor promoting M2 macrophages. Recently, studies have indicated that M2-type macrophage resembling tumor-associated macrophages (TAMs) might be used as an independent prognostic factor for gastric cancer. This review will discuss the possible use of TAMs as prognostic tools for gastric cancer and whether they are suitable for use in clinical environment.

Evaluation of procalcitonin for predicting septic multiorgan failure and overall prognosis in secondary peritonitis: a prospective, international multicenter study.

HYPOTHESIS: Infections and sepsis are major complications in secondary peritonitis and still represent a diagnostic challenge. We hypothesized that the laboratory marker procalcitonin would provide an early and reliable assessment of septic complications. DESIGN: Prospective, international, multicenter inception cohort study. SETTING: Five European surgical referral centers. PATIENTS: Eighty-two patients with intraoperatively proven secondary peritonitis were enrolled within 96 hours of symptom onset. MAIN OUTCOME MEASURES: Procalcitonin and the laboratory routine marker C-reactive protein (CRP) were prospectively assessed and monitored for a maximum of 21 consecutive days. RESULTS: Procalcitonin concentrations were most closely correlated with the development of septic multiorgan dysfunction syndrome (MODS), with peak levels occurring early after symptom onset or during the immediate postoperative course. No such correlation was observed for CRP. According to receiver operating characteristic analysis, a procalcitonin value of 10.0 ng/mL or greater on 2 consecutive days was superior to a CRP level of 210 mg/L or greater for predicting septic MODS, with sensitivity, specificity, and positive and negative predictive values of 65%, 92%, 83%, and 81% for procalcitonin and 67%, 58%, 49%, and 74% for CRP, respectively (P<.001). Assessment of septic MODS was already possible on the first 2 postoperative days, with similar sensitivity and specificity. Persisting procalcitonin levels greater than 1.0 ng/mL beyond the first week after disease onset strongly indicated nonsurvival and were significantly better than CRP in assessing overall prognosis (P<.001). CONCLUSIONS: Procalcitonin monitoring is a fast and reliable approach to assessing septic MODS and overall prognosis in secondary peritonitis. This single-test marker improves stratification of patients who will develop clinically relevant complications.

Increasing the Inflammatory Competence of Macrophages with IL-6 or with Combination of IL-4 and LPS Restrains the Invasiveness of Pancreatic Cancer Cells.

Recent studies suggest that pro-inflammatory type M1 macrophages inhibit tumor progression and that anti-inflammatory M2 macrophages enhance it. The aim of this study was to examine the interaction of type M1 and M2 macrophages with pancreatic cancer cells. We studied the migration rate of fluorescein stained pancreatic cancer cells on Matrigel cultured alone or with Granulocyte-Macrophage Colony Stimulating Factor (GM-CSF) differentiated macrophages or with Macrophage Colony Stimulating Factor (M-CSF) differentiated macrophages, skewing the phenotype towards pro- and anti-inflammatory direction, respectively. Macrophage differentiation was assessed with flow cytometry and the cytokine secretion in cell cultures with cytokine array. Both GM-CSF and M-CSF differentiated macrophages increased the migration rate of primary pancreatic adenocarcinoma cell line (MiaPaCa-2) and metastatic cell line (HPAF-II). Stimulation with IL6 or IL4+LPS reversed the macrophages' increasing effect on the migration rate of MiaPaCa-2 completely and partly of HPAF-II. Co-culture with MiaPaCa-2 reduced the inflammatory cytokine secretion of GM-CSF differentiated macrophages. Co-culture of macrophages with pancreatic cancer cells seem to change the inflammatory cytokine profile of GM-CSF differentiated macrophages and this might explain why also GM-CSF differentiated macrophages promoted the invasion. Adding IL6 or IL4+LPS to the cell culture with MiaPaCa-2 and GM-CSF or M-CSF differentiated macrophages increased the secretion of inflammatory cytokines and this could contribute to the reversion of the macrophage induced increase of cancer cell migration rate.

Effects of salmon oil and corn oil on plasma lipid level and hepato-biliary cholesterol metabolism in rats.

The aim of this work was to compare the effects of n-3 and n-6 fatty acids on plasma lipid level and hepato-biliary cholesterol metabolism by studying rats fed semi-synthetic diets enriched with either 10% salmon oil, 10% corn oil, or a blend of 6% corn oil and 4% salmon oil. After 4 weeks of feeding, a drop in plasma lipid level was noted in the salmon oil group in comparison to the control group, whereas no change was observed in the corn oil group. An increase in production of cholesterol ester by the liver was recorded in the salmon oil group with a marked enhancement in acyl-CoA:cholesterol acyltransferase (ACAT: EC 2.3.1.26) activity and hepatic cholesterol concentration. Corn oil did not affect either ACAT activity or hepatic cholesterol storage. All bile parameters (flow, bile salts, phospholipids, cholesterol) increased in the salmon oil group, but the molar ratio of cholesterol participation in the bile secretion decreased. These changes in bile composition, as well as in hepatic metabolism of cholesterol, may help to explain the hypolipidemia following the intake of fish oil.

Subcellular localization of rat gastric phospholipase A2.

In the present study, we have performed experiments to gain some insight into the subcellular localization and biochemical properties of gastric mucosal phospholipase A2. After classical subcellular fractionation of whole glandular stomach mucosa, we found that gastric phospholipase A2 was essentially enriched in the 105,000 x g pellet that contains microsomes and plasma membranes. Except for the cytosol, all the subcellular fractions exhibited similar phospholipase A2 activity (i.e., optimum of pH, calcium dependence, apparent Km and positional specificity). The high-speed pellet was further characterized by ultracentrifugation on a sucrose gradient. Data showed that the sedimentation profile of phospholipase A2 was quite similar to those of plasma membrane markers and more specifically to an apical membrane marker. These results, taken together, showed that a gastric phospholipase A2 is distributed among the various subcellular fractions (as a result of cross-contamination) together with the membrane fraction on which it is associated. It is proposed that this fraction is the apical plasma membrane which would be the main site of phospholipase A2 action for arachidonic acid release. Lysophospholipase showed the same sedimentation profile as phospholipase A2, whereas acyl CoA-lysophosphatidylcholine: acyltransferase mainly sedimented with heavy microsomes. The substrate specificity of the enzyme was assessed by endogenous hydrolysis of gastric mucosal phospholipids. We were able to show that the enzyme acts at nearly the same rate on two major gastric membrane phospholipids, namely phosphatidylcholine and phosphatidylethanolamine.

Enhanced growth of pancreatic tumors in SPARC-null mice is associated with decreased deposition of extracellular matrix and reduced tumor cell apoptosis.

SPARC, a matricellular glycoprotein, modulates cellular interaction with the extracellular matrix (ECM). Tumor growth and metastasis occur in the context of the ECM, the levels and deposition of which are controlled in part by SPARC. Tumor-derived SPARC is reported to stimulate or retard tumor progression depending on the tumor type, whereas the function of host-derived SPARC in tumorigenesis has not been explored fully. To evaluate the function of endogenous SPARC, we have examined the growth of pancreatic tumors in SPARC-null (SP(-/-)) mice and their wild-type (SP(+/+)) counterparts. Mouse pancreatic adenocarcinoma cells injected s.c. grew significantly faster in SP(-/-) mice than cells injected into SP(+/+) animals, with mean tumor weights at sacrifice of 0.415 +/- 0.08 and 0.086 +/- 0.03 g (P < 0.01), respectively. Lack of endogenous SPARC resulted in decreased collagen deposition and fiber formation, alterations in the distribution of tumor-infiltrating macrophages, and decreased tumor cell apoptosis. There was no difference in microvessel density of tumors from SP(-/-) or SP(+/+) mice. However, tumors grown in SP(-/-) had a lower percentage of blood vessels that expressed smooth muscle alpha-actin, a marker of pericytes. These data reflect the importance of ECM deposition in regulating tumor growth and demonstrate that host-derived SPARC is a critical factor in the response of host tissue to tumorigenesis.

SPARC-thrombospondin-2-double-null mice exhibit enhanced cutaneous wound healing and increased fibrovascular invasion of subcutaneous polyvinyl alcohol sponges.

Secreted protein acidic and rich in cysteine (SPARC) and thrombospondin-2 (TSP-2) are structurally unrelated matricellular proteins that have important roles in cell-extracellular matrix (ECM) interactions and tissue repair. SPARC-null mice exhibit accelerated wound closure, and TSP-2-null mice show an overall enhancement in wound healing. To assess potential compensation of one protein for the other, we examined cutaneous wound healing and fibrovascular invasion of subcutaneous sponges in SPARC-TSP-2 (ST) double-null and wild-type (WT) mice. Epidermal closure of cutaneous wounds was found to occur significantly faster in ST-double-null mice, compared with WT animals: histological analysis of dermal wound repair revealed significantly more mature phases of healing at 1, 4, 7, 10, and 14 days after wounding, and electron microscopy showed disrupted ECM at 14 days in these mice. ST-double-null dermal fibroblasts displayed accelerated migration, relative to WT fibroblasts, in a wounding assay in vitro, as well as enhanced contraction of native collagen gels. Zymography indicated that fibroblasts from ST-double-null mice also produced higher levels of matrix metalloproteinase (MMP)-2. These data are consistent with the increased fibrovascular invasion of subcutaneous sponge implants seen in the double-null mice. The generally accelerated wound healing of ST-double-null mice reflects that described for the single-null animals. Importantly, the absence of both proteins results in elevated MMP-2 levels. SPARC and TSP-2 therefore perform similar functions in the regulation of cutaneous wound healing, but fine-tuning with respect to ECM production and remodeling could account for the enhanced response seen in ST-double-null mice.

Influence of obesity and body fat distribution on postprandial lipemia and triglyceride-rich lipoproteins in adult women.

We know that upper body obesity is associated with metabolic complications, but we don't know how regional body fat distribution influences postprandial lipemia in obese adults. Thus, this study explored the respective effects of android or gynoid types of obesity and fasting triglyceridemia on postprandial lipid metabolism and especially triglyceride-rich lipoproteins. Twenty-four obese and 6 lean normotriglyceridemic women (control), age 24-57 yr, were enrolled. Among obese women with an android phenotype, 9 exhibited normal plasma triglyceride levels (mean: 1.38 mmol/L) (NTAO), and 7 displayed a frank hypertriglyceridemia (mean: 2.40 mmol/L) (HTAO). The 8 patients with a gynoid phenotype had normal triglyceride levels (mean: 1.00 mmol/L) (GO). All were given a mixed test meal providing 40 g triglycerides. Serum and incremental chylomicron triglycerides 0-7 h areas under the curve (AUCs) as well as triglyceride levels in apoB-48-containing triglyceride-rich lipoprotein (TRLs) or chylomicrons were significantly higher in HTAOs and NTAOs than in GOs and controls postprandially. The size of chylomicron particles was bigger in controls and GOs than in HTAOs and NTAOs postprandially. Android obese subjects showed abnormally elevated fasting apoB-48 and apoB-100 triglyceride-rich lipoprotein (TRL) levels. Most abnormalities that were found correlated to plasma levels of insulin and apoC-III. In conclusion, an abnormal postprandial lipid pattern is a trait of abdominal obesity even without fasting hypertriglyceridemia.

Effects of oat bran, rice bran, wheat fiber, and wheat germ on postprandial lipemia in healthy adults.

Six normolipidemic males ingested on separate days a low-fiber test meal [2.8 g dietary fiber (TDF)] containing 70 g fat and 756 mg cholesterol, enriched or not with 10 g TDF as oat bran, rice bran, or wheat fiber or 4.2 g TDF as wheat germ. Fasting and postmeal blood samples were obtained for 7 h and chylomicrons were isolated. Adding fibers to the test meal induced no change in serum glucose or insulin responses. The serum triglyceride response was lower (P less than or equal to 0.05) in the presence of oat bran, wheat fiber, or wheat germ and chylomicron triglycerides were reduced with wheat fiber. All fiber sources reduced chylomicron cholesterol. Cholesterolemia decreased postprandially for 6 h and was further lowered in the presence of oat bran. Serum apolipoprotein (apo) A-1 and apo B concentrations were not affected. Thus, dietary fibers from cereals may reduce postprandial lipemia in humans to a variable extent.

Effects of moderate amounts of emulsified dietary fat on postprandial lipemia and lipoproteins in normolipidemic adults.

Eight normolipidemic males ingested a meal containing either 42 g fat or 31 g fat in the form of emulsions (9.0 and 9.2 m2) and a fixed amount of retinyl palmitate. Fasting and postmeal blood samples were obtained for 7 h. Serum and chylomicron triglyceride responses were related to the amount of fat ingested and peaked after 2-3 h. The chylomicron retinyl palmitate response was lower (P < or = 0.05) with the 31-g fat supply. After the 42-g fat intake, but not after the 31-g fat intake, serum free cholesterol and phospholipids increased and esterified cholesterol decreased postprandially. Significantly different responses were observed after both meals for low-density-lipoprotein (LDL) free cholesterol, very-low-density-lipoprotein (VLDL) and LDL esterified cholesterol, and high-density-lipoprotein (HDL) phospholipids. These data show that ingesting 31 g instead of 42 g fat in a meal reduces postmeal lipoprotein variations and suggest that a threshold level of dietary fat should be overcome to promote significant postprandial changes in lipoprotein particles.

Chronic oat bran intake alters postprandial lipemia and lipoproteins in healthy adults.

This study evaluates the possible interaction between chronic oat bran intake and the postmeal metabolic response. Six normolipidemic men consumed three different diets for 14 d, at the end of which they consumed a test meal. The diets were C (control), basal low-fiber diet (15.6 g fiber/d) and a low-fiber (2.8 g fiber) test meal; OB (oat bran), basal low-fiber diet and a 40-g oat bran-enriched test meal (12.8 g fiber); and OB-A (oat bran-adaptation), 14-d oat bran (40 g/d) supplemented diet (23.8 g fiber/d) and an oat bran test meal (12.8 g fiber). The diets were fed in a random order. Fasting and postmeal blood samples were obtained for 7 h and lipoproteins were isolated. Adding oat bran to the test meals markedly reduced the postmeal insulin rise (P < 0.05). Compared with the low-fiber control diet, the effects elicited postprandially by adding oat bran to a single meal were enhanced after 14 d of oat bran feeding, ie, increased plasma triglycerides, phospholipids, and free cholesterol; decreased plasma esterified cholesterol; increased chylomicron and small-sized triglyceride-rich lipoprotein triglycerides; increased LDL and HDL free cholesterol; and decreased HDL esterified cholesterol. Thus, chronic oat bran feeding alters the postmeal response in human subjects.

Dietary cholesterol is secreted in intestinally derived chylomicrons during several subsequent postprandial phases in healthy humans.

BACKGROUND: The process of intestinal absorption and chylomicron resecretion of dietary cholesterol in humans is poorly understood. OBJECTIVE: The present study aimed to test the hypothesis that dietary cholesterol ingested during a given meal is resecreted into chylomicrons (and plasma) during several subsequent postprandial periods. DESIGN: Seven healthy subjects ingested 3 comparable mixed test meals (at 0, 8, and 24 h) containing a given amount of fat (49 g) and cholesterol (157 mg); blood samples were taken 3 and 6 h after each test meal and 48 and 72 h after the beginning of the experiment. Heptadeuterated dietary cholesterol was present in the first test meal only, enabling its specific determination with use of gas chromatography-mass spectrometry. Chylomicrons, LDL, and HDL were isolated and lipids were quantified. RESULTS: In apolipoprotein B-48-containing chylomicrons, deuterated cholesterol concentrations were moderate after the first meal (1.3 x 10(-4) mmol/L), reached a maximum after the second meal (2.4 x 10(-4) mmol/L), and were still elevated after the third meal (1.7 x 10(-4) mmol/L). In plasma, LDL and HDL cholesterol enrichment in deuterated cholesterol was lower than in chylomicrons and plateaued after 24--48 h. Estimates of newly secreted exogenous deuterated cholesterol in chylomicrons indicate that 30.7%, 55.2%, and 14.1% of the total was secreted after the first, second, and third meals, respectively. CONCLUSION: Ingested dietary cholesterol is secreted by the small intestine in chylomicrons into the circulation during > or =3 subsequent postprandial periods in healthy humans. This likely results from a complex multistep intestinal processing of cholesterol with dietary fat as a driving force.

Effects of lowering fat and increasing dietary fiber on fasting and postprandial plasma lipids in hypercholesterolemic subjects consuming a mixed Mediterranean-Western diet.

The aim of this study was to evaluate the cholesterol-lowering effects of reducing fat and increasing or not increasing dietary fiber in subjects consuming a mixed Mediterranean-Western diet. Thirty-one free-living, mildly hypercholesterolemic subjects were randomly allocated to two groups. Subjects in both groups first shifted for 4 wk to a low-fat, low-fiber diet (LFLFD). For an additional 4-wk period, subjects in group 1 continued consuming the LFLFD whereas subjects in group 2 consumed a low-fat, high-fiber diet (LFHFD). Most dietary fatty acids were monounsaturated (38-41%) and fibers, when provided (up to 35 g/d), came from unrefined cereals, legumes, and soluble-fiber-enriched ready-to-eat cereals. After period 1 of the LFLFD, mean serum and low-density-lipoprotein (LDL)-cholesterol concentrations of subjects in groups 1 (-12.5% and -15.5%, respectively) and 2 (-10.5% and -15.5%, respectively) decreased significantly from baseline (P < 0.05). After period 2, mean serum and LDL-cholesterol concentrations of subjects consuming the LFLFD (group 1) were still lower (by 8.8% and 9.2%, respectively, from baseline) whereas in subjects consuming the LFHFD (group 2) these values decreased further to significantly lower values (14.2% and 17.6% from baseline, respectively). Fasting high-density-lipoprotein (HDL) cholesterol, apolipoprotein A-I, glycemia, and insulinemia did not change significantly. In seven men, postprandial lipemia transiently increased more after a breakfast test meal at the completion of the LFHFD period than after the LFLFD period. In conclusion, an LFHFD more comparable with the traditional Mediterranean diet may improve the dietary management of moderate hypercholesterolemia.