An in vitro model for the study of the role of innervation in circumvallate papillae morphogenesis.

The following study was done to demonstrate the reliability of an in vitro model for use in the study of early events and the role of innervation in mouse circumvallate papillae development. Gestational day (gd)-11 fetuses were partially dissected to produce explants that included the mandibular, hyoid, third and fourth branchial arches and their ganglia. In ganglionectomized explants, the nodose ganglia and either the geniculate, petrosal or both ganglia were removed. Explants were cultivated in roller tube culture for 24, 48, 72, and 96 h of culture and examined for the presence of papillary structures. Innervation was verified by immunostaining for neural cell adhesion molecule (NCAM). In all control explants, circumvallate papillae had formed by 72 h in culture. These papillae were innervated by fibers originating in petrosal or nodose ganglia, although, in a small number, fibers from the geniculate also contributed. Circumvallate papillae also formed in some explants in which either the geniculate or petrosal ganglia had been removed. However, placodal structures failed to mature into papillary structures even by 96 h in explants in which both ganglia had been removed. Our results demonstrate that an in vitro model using branchial arch explants supports the morphogenesis of an epithelial placode through the formation of a definite papillary structure, the circumvallate papilla, with an integrated nerve. Our results also indicate that, whereas the initial stages in gustatory papillae formation, the formation of a placode, are nerve-independent, the maturation of the placodal structure to form a papilla requires the presence of an intact nerve.     

Targeting aurora kinase with MK-0457 inhibits ovarian cancer growth

PURPOSE: The Aurora kinase family plays pivotal roles in mitotic integrity and cell cycle. We sought to determine the effects of inhibiting Aurora kinase on ovarian cancer growth in an orthotopic mouse model using a small molecule pan-Aurora kinase inhibitor, MK-0457. EXPERIMENTAL DESIGN: We examined cell cycle regulatory effects and ascertained the therapeutic efficacy of Aurora kinase inhibition both alone and combined with docetaxel using both in vitro and in vivo ovarian cancer models. RESULTS: In vitro cytotoxicity assays with HeyA8 and SKOV3ip1 cells revealed >10-fold greater docetaxel cytotoxicity in combination with MK-0457. After in vivo dose kinetics were determined using phospho-histone H3 status, therapy experiments with the chemosensitive HeyA8 and SKOV3ip1 as well as the chemoresistant HeyA8-MDR and A2780-CP20 models showed that Aurora kinase inhibition alone significantly reduced tumor burden compared with controls (P values<0.01). Combination treatment with docetaxel resulted in significantly improved reduction in tumor growth beyond that afforded by docetaxel alone (P 相似文献   

Fetal weight estimation from lengths and volumes found by three-dimensional ultrasonic measurements.

A custom-built computer system combined with a commercial real-time ultrasonic scanner was used to predict fetal weight. A special three-dimensional (3D) locating system provided 3D coordinates of fetal surface points imaged on multiple ultrasound scans. The 3D coordinates were used to develop length and volume variables that are not available with commercial instruments. Multiple regressions were used to compare these lengths and volumes with more conventional diameters and circumferences for their ability to predict fetal weight. Measurements were made on 41 live fetuses within 48 hours prior to delivery (weight range 1,985-4,734 g, mean weight 3,421 g). Combinations of 19 measured variables were analyzed against birth weight and the natural log of birth weight. The correlation between log birth weight and combinations including lengths from 3D measurements was R = .93, SE = 73 g/kg. When volumes from 3D measurements (which are much more difficult to obtain) were added, the correlation was R = .94, SE = 69 g/kg. These results suggest that lengths from 3D measurements have the potential to improve fetal weight prediction by 25-30 per cent over current methods, which have an approximate error of 100 g/kg. The relative lack of improvement with volumes from 3D measurements is probably the result of technical problems which may be overcome with further research.     

A further study of oxalate bioavailability in foods

We extended the study of oxalate bioavailability by testing 7 additional food items: brewed tea, tea with milk, turnip greens, okra, peanuts and almonds. Nine normal subjects ingested a large serving of each of these items. The bioavailable oxalate was calculated from the increment in urinary oxalate during 8 hours after ingestion and bioavailability was determined as the percentage of total oxalate content in a given food item represented by bioavailable oxalate. Brewed tea and tea with milk, with a high oxalate content, had a low bioavailable oxalate level (1.17 and 0.44 mg. per load) because of the low oxalate availability (bioavailability of 0.08 and 0.03%). Turnip greens, with a satisfactory oxalate bioavailability (5.8%), had a negligible effect on urinary oxalate excretion, since oxalate content was relatively low (12 mg. per load). Okra, with a moderate oxalate content (264 mg. per load) had a negligible bioavailable oxalate (0.28 mg. per load). Only peanuts and almonds provided a moderate increase in oxalate excretion (3 to 5 mg. per load) due to the modest oxalate content (116 and 131 mg. per load) and oxalate bioavailability (3.8 and 2.8%). Thus, the ability of various oxalate-rich foods to augment urinary oxalate excretion depends not only on oxalate content but on the bioavailability.     

Estimation of fetal weight from ultrasonic measurements.

Ultrasonic measurements were made on 65 fetuses within 48 hours of delivery. Multiple regression analysis of birth weight and the natural logarithm of birth weight against several measured variables were obtained. The formula giving the best correlation was a polynomial regression of the natural logarithm of birth weight vs. trunk circumference, circumference, and a long axis measurement. The correlation was improved by excluding the first 15 patients but was not improved further by excluding the next 15. The best correlation was 0.944, giving a predicted birth weight error of +/- 103 Gm. (1 S.D.).     

Calcium-dependent regulator protein: Localization in mitotic apparatus of eukaryotic cells

Calcium-dependent regulator protein is a low molecular weight (17,000), thermostable, calcium binding protein which is structurally homologous to skeletal muscle troponin C. This protein is present in all nonmuscle cells and has been shown to decorate stress fibers in interphase cells by indirect immunofluorescence. Using this procedure we have investigated the distribution of the protein during mitosis of eukaryotic cells. As the cells enter prophase, the distinct cytoplasmic localization disappears commensurate with the dissolution of the cytoskeleton. The regulator protein seems to be randomly distributed throughout the prophase cell, including the region around the condensed chromosomes. However, at prometaphase, it is localized in association with the half-spindles of the mitotic apparatus. Through metaphase and most of anaphase, the protein remains localized between the chromosomes and the poles of the spindle. During late anaphase the protein is also found in the interzone region but rapidly condenses into two small regions, one on each side of the midbody that separates the daughter cells. The regulator protein is not localized in the cleavage furrow during telophase, whereas actin is demonstrable in this region. Indeed, placement of the protein during mitosis is distinct from both that of actin and that of tubulin. The localization of calcium-dependent regulator protein during mitosis suggests that it may mediate the calcium effects on the mitotic apparatus and thus play a role in chromosome movement.     

Effect of a High-Fiber Diet Compared With a Moderate-Fiber Diet on Calcium and Other Mineral Balances in Subjects With Type 2 Diabetes

OBJECTIVE

High levels of dietary fiber, especially soluble fiber, are recommended to lower serum cholesterol levels and improve glycemic control in patients with type 2 diabetes. It is not clear, however, how high levels of fiber affect mineral balance.

RESEARCH DESIGN AND METHODS

In a randomized crossover study, 13 patients with type 2 diabetes were fed a high-fiber (50 g total and 25 g soluble fiber) and a moderate-fiber (24 g total and 8 g soluble fiber) diet of the same energy, macronutrient, calcium, magnesium, and phosphorus content for 6 weeks each. Intestinal calcium absorption was determined by fecal recovery of ⁴⁷Ca. Stool weight and mineral content were assessed during 3 days, and 24-h urinary mineral content and serum chemistry were assessed over 5 days at the end of each phase. The results were compared by repeated-measures ANOVA.

RESULTS

Compared with the moderate-fiber diet, the high-fiber diet increased stool weight (165 ± 53 vs. 216 ± 63 g/day, P = 0.02) and reduced 24-h urinary calcium (3.3 ± 1.7 vs. 2.4 ± 1.2 mmol/day, P = 0.003) and phosphorus (29.2 ± 5.5 vs. 26.0 ± 3.2 mmol/day, P = 0.003) excretion and serum calcium concentration (2.33 ± 0.06 vs. 2.29 ± 0.07 mmol/l, P = 0.04). Calcium absorption, stool calcium, magnesium, and phosphorus content and serum phosphorus concentration were not significantly different with the two diets.

CONCLUSIONS

A high-fiber diet rich in soluble fiber has a small impact on calcium and phosphorus balance in subjects with type 2 diabetes. It may be prudent to ensure adequate intake of calcium and other minerals in individuals consuming a high-fiber diet.Diets high in fiber, especially soluble fiber, are associated with an improvement in serum lipid, glucose, and insulin concentrations (1,2). Because of the beneficial effects of soluble fiber on the LDL cholesterol concentration, the National Cholesterol Education Program Adult Treatment Panel III recommends consumption of 10–25 g soluble fiber per day, through dietary changes, in individuals with high LDL cholesterol concentrations (3). Fiber consumption is also emphasized by the American Diabetes Association for individuals with diabetes or glucose intolerance to help manage their glucose and lipid concentrations (4).There is some concern that a high intake of fiber may impair the absorption of minerals, especially calcium (5,6). It is postulated that dietary fiber binds with polyvalent mineral ions forming unabsorbable fiber-mineral complexes (5,6). The relationship between dietary fiber and calcium, magnesium, and phosphorus absorption or balance is controversial, however, with some studies reporting impaired mineral absorption or balance and other studies reporting no change or a positive balance with a high-fiber diet compared with a moderate-fiber diet (7–11). The conflicting results may be due to one or more methodological issues such as not closely matching the mineral content of the diets, not providing the diets, lack of randomization, and short study duration. In addition, most of the above-mentioned studies looked at the effect of fiber supplements rather than fiber-rich natural foods on mineral absorption, and thus there is limited understanding of the effect of increasing the intake of fiber-rich natural foods on mineral absorption.The objective of our study was to compare the long-term effect of a high-fiber diet particularly rich in soluble fiber with that of a moderate-fiber diet on mineral absorption and metabolism in subjects with type 2 diabetes in a randomized crossover study. The diets consisted of natural foods, were matched for calcium, magnesium, and phosphorus content, and were prepared in the metabolic kitchen. The effects of these diets on lipid and glycemic control have been published previously (2).     

Unreported alcohol use was common but did not impact hepatitis C cure in HIV‐infected persons who use drugs

We investigated the prevalence and impact of heavy alcohol use on the hepatitis C virus (HCV) care continuum amongst HIV/HCV co‐infected persons who use drugs. In the CHAMPS study, 144 HIV/HCV co‐infected persons were randomized to contingent cash incentives, peer mentors and usual care to evaluate the impact on HCV care. Alcohol use was ascertained using the 10‐item AUDIT (hazardous: male ≥8, female ≥4) and phosphatidylethanol (PEth) (heavy: ≥50 ng/mL), an alcohol biomarker. Log binomial regression was used to evaluate the association between heavy alcohol use and failure to initiate treatment and to achieve sustained virologic response (SVR). Of the 135 participants with PEth data, median age was 55 years, 59% were male, 92% were Black, 91% reported a history of drug use, and 97% were on antiretroviral therapy. Hazardous drinking was reported on AUDIT by 28% of participants, and 35% had heavy alcohol use by PEth. Of the 47 individuals with a PEth ≥50 ng/mL, 23 (49%) reported no or minimal alcohol use by AUDIT. HCV treatment was initiated in 103 of 135 participants, and SVR was achieved in 92%. PEth ≥50 ng/mL (Relative Risk [RR] 0.72, 95% CI 0.35‐1.48) was not significantly associated with failure to initiate HCV treatment or failure to achieve SVR (RR 0.85, 95% CI 0.46‐1.57).In conclusion, alcohol use was common and frequently not detected by self‐report. However, heavy alcohol use, even when measured objectively, was not associated with failure to initiate HCV treatment or to achieve cure.