Impact of potato processing on nutrients, phytochemicals, and human health.

Potatoes (Solanum tuberosum) are an important global crop that can be transformed into many products impacting several health dimensions ranging from undernutrition, food security and disease prevention to issues of overnutrition including obesity, diabetes, heart disease. Processed potato products are typically categorized as high fat and sodium foods, as well as being classified as a significant source of carbohydrate, in the form of starch. Conversely, potato products are less known for their contribution of key micronutrients (vitamin C, potassium, magnesium), fiber, and phytochemicals (phenolics and carotenoids). More recent insight into the nutritional value of potatoes and the potential of potato phytochemicals to modulate oxidative and inflammatory stress as well as the potential to alter glycemic response has resulted in increased interest in strategies to improve and leverage the nutritional quality of processed potatoes. This review summarizes critical information on nutritional profiles of potatoes and their processed products and describes the state of the science relative to the influence of in-home and common commercial processing on nutritional quality and potential impacts on human health.

Preferential accumulation of inorganic elements in Amanita muscaria from North-eastern Poland.

Concentrations of Al, Ba, Cd, Ca, Co, Cu, Fe, K, Mg, Mn, Hg, Rb, Ag, Na, Sr and Zn were analysed in fruiting bodies of A. muscaria. This mushroom is considered conditionally edible, since parboiling can detoxify its fruiting bodies from the hallucinogens and render it edible. The specific purpose of the research is the little-known phenomenon of the variability of mineral composition of mushrooms for generations harvested in the same forest areas - both in terms of their nutritional value and anthropogenic influences. Fungal materials were digested in nitric acid and analysed by a validated methods using inductively coupled plasma optical emission spectrometer (ICP-OES) and cold - vapor atomic absorption spectroscopy (CV-AAS). A. muscaria collected in the same area over the period of four years showed fluctuations in the concentrations of the essential elements Co, Cu, Fe, K, Mn, Na and Zn (p < 0.05; U Mann-Whitney test), while only Ca and Mg (p > 0.05) levels were similar. In addition, concentrations of Ag, Al, Ba, Cd, Rb and Sr in fruiting bodies fluctuated, while remained at a similar level for Hg. It is important to note that statistically significant variations in levels of several inorganic elements accumulated in A. muscaria would imply a more careful consideration would be required when assessing the nutritional value of mushroom species.

Novel carbonized bone meal for defluoridation of groundwater: Batch and column study.

Low cost naturally available bone meal was carbonized and its fluoride adsorption capacity was explored. Carbonized bone meal (CBM) produced at 550°C, 4 h carbonization time and a heating rate of 60°C/min, showed fluoride adsorption capacity of 14 mg g-1. Adsorbent was characterized using scanning electron microscopy, X-ray diffraction, X-ray fluoroscence, thermogravimetric analysis and Fourier transform infrared spectroscopy to highlight its physical and chemical properties. Best fluoride uptake capacity was observed for 0.2 mm particle size, 7 g L-1 adsorbent concentration and at pH 6.5. Fluoride uptake was endothermic and chemisorption in nature. Effective diffusivity and mass transfer coefficient were obtained as 6 × 10-11 m2 s-1 and 9 × 10-5 m s-1 from shrinking core model. Sulphate and carbonate showed the highest interference effect on adsorption of fluoride by CBM. Maximum desorption was observed at basic pH (pH 12). Fixed bed study was performed and effect of different parameters (bed height, inlet flow rate and initial concentration) was investigated. Efficiency of the adsorbent using real life fluoride contaminated groundwater solution was also observed.

Difference in release kinetics of unwashed and washed platelet-released supernatants from bone substitute materials: the impact of platelet preparation modalities.

BACKGROUND AND OBJECTIVE: In regenerative dentistry, platelet preparations are applied to stimulate bone healing and periodontal regeneration. Here, we pursue a strategy where bone substitutes are used as carriers for platelet-released supernatants. The mitogenic capacity and release kinetics of loaded bone substitutes were assessed. MATERIAL AND METHODS: Platelet-released supernatants of washed platelets (washed PRS) and platelet-released supernatants of unwashed platelets (unwashed PRS) were lyophilized onto the bone substitutes deproteinized bovine bone mineral, hydroxyapatite and ß-tricalcium phosphate. Scanning electron microscopy images were taken. Supernatants of bone substitutes were collected at hours 1, 3, 6, 24, and 48 and medium was replaced. We evaluated the protein content with the bicinchoninic acid assay and the effect on proliferation using bioassays with human periodontal fibroblasts. Release of growth factors from the loaded bone substitutes was measured based on the platelet-derived growth factor isoform (PDGF-BB) and thrombin immunoassays. Furthermore, we assessed DNA and RNA content of washed PRS and unwashed PRS. RESULTS: Unwashed PRS showed higher total protein concentrations than washed PRS, while the concentration of PDGF-BB, thrombin, DNA, RNA and their mitogenic effect was not significantly different. The bone substitute materials adsorbed protein over time but no significant changes in overall appearance was found. Supernatants collected from unwashed PRS-loaded bone substitute after 1 h induced a potent mitogenic response in periodontal fibroblasts. This pro-mitogenic capacity of the supernatants decreased over the observation period. Supernatants of washed PRS-loaded bone substitutes did not induce a substantial mitogenic effect. Levels of PDGF-BB, thrombin and protein were higher in supernatants of unwashed PRS-loaded bone substitutes than of washed PRS-loaded bone substitutes. CONCLUSION: Bone substitutes loaded with unwashed PRS, but not bone substitutes loaded with washed PRS show continuously declining release kinetics. These data suggest that plasma components in platelet preparations can modify the release kinetics profile.

Tef: The Rising Ancient Cereal: What do we know about its Nutritional and Health Benefits?

This review covers the nutritional significance of tef cereal as compared to other common cereals with emphasis on carbohydrate content and starch digestibility, protein content, iron and zinc bioavailability and antioxidant potentials. Tef is a gluten free cereal and contains the highest iron and calcium among other cereals. It has high micro- and macro- nutritional profile and is becoming globally popular in the healthy grain food chain. Tef starch has a high gelatinization temperature, an essential precondition in the preparation of low glycemic index foods. There are significantly conflicting reports of iron content of tef ranging from 5 to 150 mg/100 g dm. The traditional fermentation of injera reduced majority of the phytic acid but no significant change to mineral bioavailability was observed. This review indicated that studies on starch digestibility, protein characterization, amylase and protease inhibitors, mineral bioavailability and antioxidant potentials are needed to further explore the nutritional and health benefits of tef.

Visualization of Uptake of Mineral Elements and the Dynamics of Photosynthates in Arabidopsis by a Newly Developed Real-Time Radioisotope Imaging System (RRIS).

Minerals and photosynthates are essential for many plant processes, but their imaging in live plants is difficult. We have developed a method for their live imaging in Arabidopsis using a real-time radioisotope imaging system. When each radioisotope,(22)Na,(28)Mg,(32)P-phosphate,(35)S-sulfate,(42)K,(45)Ca,(54)Mn and(137)Cs, was employed as an ion tracer, ion movement from root to shoot over 24 h was clearly observed. The movements of(22)Na,(42)K,(32)P,(35)S and(137)Cs were fast so that they spread to the tip of stems. In contrast, high accumulation of(28)Mg,(45)Ca and(54)Mn was found in the basal part of the main stem. Based on this time-course analysis, the velocity of ion movement in the main stem was calculated, and found to be fastest for S and K among the ions we tested in this study. Furthermore, application of a heat-girdling treatment allowed determination of individual ion movement via xylem flow alone, excluding phloem flow, within the main stem of 43-day-old Arabidopsis inflorescences. We also successfully developed a new system for visualizing photosynthates using labeled carbon dioxide,(14)CO2 Using this system, the switching of source/sink organs and phloem flow direction could be monitored in parts of whole shoots and over time. In roots,(14)C photosynthates accumulated intensively in the growing root tip area, 200-800 µm behind the meristem. These results show that this real-time radioisotope imaging system allows visualization of many nuclides over a long time-course and thus constitutes a powerful tool for the analysis of various physiological phenomena.

Ultrasonic assessment of the effects of self-assembling peptide scaffolds on preventing enamel demineralization.

OBJECTIVES: This study evaluates the effect of self-assembling peptide P11-4 (Curodont Repair, CDR) on bovine enamel remineralization by measuring changes in ultrasonic propagation velocity. METHODS: Six specimens per group were prepared by sectioning bovine teeth into enamel blocks. These blocks were then immersed in lactic acid buffer solution (pH = 4.75) for 10 min twice a day and stored in artificial saliva. Other specimens were first treated with CDR, followed by a 10-min immersion in the lactic acid buffer solution twice a day, before storage in artificial saliva. The propagation time of longitudinal ultrasonic waves was measured using a pulser/receiver. Six specimens were used for each treatment protocol. The obtained data were statistically analyzed using ANOVA followed by Tukey's honestly significant difference tests (α = 0.05). Specimens were observed using laser scanning microscopy and scanning electron microscopy. RESULTS: Sonic velocity was found to decrease with time for specimens stored in the demineralizing solution. On the other hand, increases in sonic velocity were found for specimens treated with CDR. These specimens also exhibited signs of mineral deposition. CONCLUSIONS: By measuring the ultrasonic propagation velocity, it can be concluded that CDR application has an ability to promote bovine enamel remineralization.

Silicon occurrence, uptake, transport and mechanisms of heavy metals, minerals and salinity enhanced tolerance in plants with future prospects: A review.

Recently, heavy metals pollution due to industrialization and urbanization, use of untreated wastewater and unreasonable use of pesticides and fertilizers is increasing rapidly, resulting in major threat to the environment and contaminate soils. Silicon (Si) is the second most abundant element in the earth crust after oxygen. Although it's higher accumulation in plants, yet Si has not been listed as essential nutrient however, considered as beneficial element for growth of plants particularly in stressed environment. Research to date has demonstrated that silicon helps the plants to alleviate the various biotic and abiotic stresses. This review article presents a comprehensive update about Si and heavy metals, minerals and salinity stresses, and contained the progress about Si so far done worldwide in the light of previous studies to evaluate the ecological importance of Si. Moreover, this review will also be helpful to understand the Si uptake ability and its benefits on plants grown under stressed environment. Further research needs for Si-mediated mitigation of heavy metals and mineral nutrients stresses are also discussed.

Demonstration of uniformity of calcium absorption in adult dogs and cats.

A meta-analysis was conducted to understand quantitative aspects of calcium (Ca) and phosphorus (P) absorption in adult dogs and cats. 34 studies in dogs and 14 studies in cats met the criteria for inclusion in the meta-analysis. Intake and faecal excretion values of Ca and P were subjected to a modified Lucas test and subsequent regression analyses. According to the current scientific consensus, Ca true digestibility (absorption) should increase at low Ca intake and decrease at high Ca intake. If true, this should result in a nonlinear relationship between the percentage of Ca excreted and dietary Ca intake. The present meta-analysis showed a highly significant linear relationship (p < 0.0001) between Ca intake and Ca excretion suggesting a lack of systematic quantitative adaptation in true Ca digestibility. This finding suggests either that the time period covered by standard digestion trials is too short to induce adaptation mechanisms or that dogs and cats at maintenance will not efficiently alter quantitative Ca absorption percentage according to the amount ingested. If the latter is true, a dietary Ca supply differing greatly from the recommended dietary intake might impair the health of cats and dogs when fed long term. The data plots for P intake and faecal excretion were less uniform suggesting other factors not just dietary intake influence faecal P excretion. In adult cats, the dietary Ca:P ratio strongly influenced the true digestibility of P, whereas this effect was less marked in adult dogs. Faecal P excretion was significantly correlated to faecal Ca excretion in both species (p < 0.0001), and surprisingly, the level of P intake did not appear to be an important determinant of true digestibility of P.

Bioaccessibility of arsenic in mining-impacted circumneutral river floodplain soils.

Floodplain soils are frequently contaminated with metal(loid)s due to present or historic mining, but data on the bioaccessibility (BA) of contaminants in these periodically flooded soils are scarce. Therefore, we studied the speciation of As and Fe in eight As-contaminated circumneutral floodplain soils (≤ 21600 mg As/kg) and their size fractions using X-ray absorption spectroscopy (XAS) and examined the BA of As in the solids by in-vitro gastrointestinal (IVG) extractions. Arsenopyrite and As(V)-adsorbed ferrihydrite were identified by XAS as the predominant As species. The latter was the major source for bioaccessible As, which accounted for 5-35% of the total As. The amount of bioaccessible As increased with decreasing particle size and was controlled by the slow dissolution kinetics of ferrihydrite in the gastric environment (pH 1.8). The relative BA of As (% of total) decreased with decreasing particle size only in a highly As-contaminated soil--which supported by Fe XAS--suggests the formation of As-rich hydrous ferric oxides in the gastric extracts. Multiple linear regression analyses identified Al, total As, C(org), and P as main predictors for the absolute BA of As (adjusted R(2) ≤ 0.977). Health risk assessments for residential adults showed that (i) nearly half of the bulk soils may cause adverse health effects and (ii) particles <5 µm pose the highest absolute health threat upon incidental soil ingestion. Owing to their low abundance, however, health risks were primarily associated with particles in the 5-50 and 100-200 µm size ranges. These particles are easily mobilized from riverbanks during flooding events and dispersed within the floodplain or transported downstream.

Effect of two microbial phytases on mineral availability and retention and bone mineral density in low-phosphorus diets for broilers.

1. The efficacy of supplementation of a low-phosphorus (low-P) maize-soyabean meal diet for broiler chickens with two different microbial (fungal and bacterial) phytases was examined. 2. Broiler chickens received a low-P maize-soyabean meal diet containing either no phytase or one of the two phytases included at one and two times the manufacturer's recommended inclusion level for 21 d. 3. Titanium dioxide was included in the diets as an indigestible marker. Excreta were collected quantitatively from d 18 to 21, and at the end of the study the birds were killed and ileal digesta and leg bone samples collected. 4. No differences were observed for body weight gain and feed intake or apparent metabolisable energy (AME) among all dietary treatment groups. 5. Dietary phytase supplementation improved the apparent retention of Ca, Na and Cu and ileal phytate P absorption from 32% to 44% across inclusion levels. 6. Bone mineral density (BMD) was improved for both phytases across inclusion levels by, on average, 9% for the tibia and 13% for the femur. 7. Dietary phytase supplementation of the low-P diet improved apparent ileal digestibility of serine, glycine, valine, isoleucine, tyrosine, histidine, lysine and arginine. 8. When the results from the present study were combined with the results from other similar published studies and analysed statistically, factors such as dietary P and Ca concentration, as well as bird breed and age, rather than the type or activity of microbial phytase, had the greatest impact on the extent to which dietary supplementation improved P and Ca retention. 9. More work is required to explain the interrelationships between the multiple factors influencing the efficacy of phytase on the availability of dietary minerals.

Effect of fluoride, lesion baseline severity and mineral distribution on lesion progression.

The present study investigated the effects of fluoride (F) concentration, lesion baseline severity (ΔZ(base)) and mineral distribution on lesion progression. Artificial caries lesions were created using three protocols [methylcellulose acid gel (MeC), hydroxyethylcellulose acid gel (HEC), carboxymethylcellulose acid solution (CMC)] and with low and high ΔZ(base) groups by varying demineralization times within protocols. Subsequently, lesions were immersed in a demineralizing solution for 24 h in the presence of 0, 1, 2 or 5 ppm F. Changes in mineral distribution characteristics of caries lesions were studied using transverse microradiography. At baseline, the protocols yielded lesions with three distinctly different mineral distributions. Secondary demineralization revealed differences in F response between and within lesion types. In general, lowΔZ lesions were more responsive to F than highΔZ lesions. LowΔZ MeC lesions showed the greatest range of response among all lesions, whereas highΔZ HEC lesions were almost unaffected by F. Laminations were observed in the presence of F in all but highΔZ HEC and CMC lesions. Changes in mineral distribution effected by F were most pronounced in MeC lesions, with remineralization/mineral redeposition in the original lesion body at the expense of sound enamel beyond the original lesion in a dose-response manner. Both ΔZ(base) and lesion mineral distribution directly impact the F response and the extent of secondary demineralization of caries lesions. Further studies - in situ and on natural white spot lesions - are required to better mimic in vivo caries under laboratory conditions.

Mechanisms of gold biomineralization in the bacterium Cupriavidus metallidurans.

While the role of microorganisms as main drivers of metal mobility and mineral formation under Earth surface conditions is now widely accepted, the formation of secondary gold (Au) is commonly attributed to abiotic processes. Here we report that the biomineralization of Au nanoparticles in the metallophillic bacterium Cupriavidus metallidurans CH34 is the result of Au-regulated gene expression leading to the energy-dependent reductive precipitation of toxic Au(III)-complexes. C. metallidurans, which forms biofilms on Au grains, rapidly accumulates Au(III)-complexes from solution. Bulk and microbeam synchrotron X-ray analyses revealed that cellular Au accumulation is coupled to the formation of Au(I)-S complexes. This process promotes Au toxicity and C. metallidurans reacts by inducing oxidative stress and metal resistances gene clusters (including a Au-specific operon) to promote cellular defense. As a result, Au detoxification is mediated by a combination of efflux, reduction, and possibly methylation of Au-complexes, leading to the formation of Au(I)-C-compounds and nanoparticulate Au(0). Similar particles were observed in bacterial biofilms on Au grains, suggesting that bacteria actively contribute to the formation of Au grains in surface environments. The recognition of specific genetic responses to Au opens the way for the development of bioexploration and bioprocessing tools.

Effect of a novel phytase on growth performance, apparent metabolizable energy, and the availability of minerals and amino acids in a low-phosphorus corn-soybean meal diet for broilers.

The addition of microbial phytase to diets for broiler chickens has been shown to improve the availability of phytate P, total P, some other minerals, and amino acids. In this study, the effect of a novel microbial phytase expressed by synthetic genes in Aspergillus oryzae on amino acid and mineral availability was assessed. Phytase was incorporated (1,000 and 2,000 U/kg) into low-P corn-soybean meal-based diets for broilers. Broilers received the experimental diets for 3 wk, and excreta were collected from d 18 to 21 for the determination of AME and mineral retention. On the 22nd day, the broilers were killed and the left leg removed and ileal digesta collected. Ileal phytate P and total P absorption, ileal amino acid digestibility, as well as the bone mineral content and bone mineral density were determined. Ileal phytate P absorption and absorbed phytate P content of the low-P corn-soybean meal diet were significantly (P < 0.05) higher after dietary inclusion of the novel phytase (49-60% and 65-77% higher, respectively). Apparent ileal total P absorption and apparent total P retention was 12 to 16% and 14 to 19% higher (P < 0.05), respectively, after dietary inclusion of phytase. The bone mineral content and bone mineral density in the tibia were 32 to 35% and 19 to 21% higher (P < 0.05), respectively, after dietary phytase inclusion. The apparent ileal digestibility of threonine, tyrosine, and histidine increased significantly (P < 0.05) by 14, 9, and 7%, respectively, after dietary inclusion of microbial phytase. Overall, the inclusion of a novel microbial phytase into a low-P corn-soybean meal diet for broiler chickens greatly increased phytate P and total P absorption, bone mineral content and density, as well as the digestibility of some amino acids.

Externalities from grain consumption: a survey.

The US Department of Agriculture (USDA) publishes their MyPyramid plan as a recommended eating model for all Americans. As part of this model, grain consumption is emphasized. This grain consumption has the potential to generate positive externalities, such as reduced rates of obesity, diabetes and other chronic diseases. Such positive externalities can potentially produce tangible economic benefits in terms of public health. In contrast, newer nutritional research shows that grain consumption may have negative effects on health for certain population groups. Celiac disease is four times as common as it was 50 years ago and is often under-diagnosed. Other population groups exhibit gluten sensitivity which can impact the development of asthma, allergies and neurological difficulties. This survey intends to provide a comprehensive description of both the positive and negative externalities associated with grain consumption and the resulting impact on human health.

[Mineral bioaccessibility in yerba mate (Ilex paraguariensis St) infusions and mixtures with iron fortified milk]. / Bioaccesibilidad de minerales en infusiones de yerba mate (Ilex paraguariensis St) y en mezclas con leches fortificadas con hierro.

The bioaccesibility of various minerals in infusions of yerba male (mate cocido) and preparations with Fe-fortified milk was assessed to determine the influence of the infusions on the potential bioavailability of intrinsic minerals and fortified Fe. The dialyzability (D) of iron, calcium, magnesium and zinc was evaluated, as indicator of bioaccesibility in milk samples fortified with ferrous sulfate (FS), ferric bisglicinate GF) and EDTANaFe. Dialyzability was also evaluated in mixtures of milk with mate cocido and in infusions cooked with Fe-fortified milk. In each case the effect of ascorbic acid (AA) in a ratio Fe: AA 1:4 was studied. In the mate cocido FeD was zero and increased to 15% with the addition of AA. The FeD in milk with SF, BGF and EDTANaFe (1.2, 1.0 and 27.4 respectively), increased with the addition of AA to 2.9, 3.5 and 24.8. The FeD in the mixture milk: mate cocido was 4.7%, 5.7% and 31.2% for SF, BGF and EDTANaFe respectively. With the addition of AA was 13.5%, 13.7% and 25.7%. In infusions cooked with SF fortified milk, the values were lower than those of the mixture. The CaD did not show significant changes in Fe fortified milk and its preparations with yerba mate, while the MgD and ZnD only showed a significant reduction in infusion cooked with Fe-fortified milk. The use of infusions of yerba mate does not provide significant amounts of minerals. However, its use in mixtures with milk will not adversely affect the availability of Fe in that matrix.

Processing of four different cooking methods of Oudemansiella radicata: Effects on in vitro bioaccessibility of nutrients and antioxidant activity.

The purpose of this study is to evaluate the bioaccessibility of nutrients and antioxidant activity of O. radicata after subjecting to four types of domestic cooking and followed by in vitro digestion. The result demonstrated that the group with the lowest amino acid release and the degree of protein hydrolysis (5.6%) was frying, but both reducing sugar content and antioxidant activity were the highest. The composition of fatty acids was different than undigested samples, especially the relative content of linolenic acid was significantly decreased (e.g., 34.49 to 8.23%, boiled). The difference of the minerals bioaccessibility was slightly affected by the cooking method, but mainly related to their natural properties, such as the highest phosphorus (62.73%) and the lowest iron (21.53%) in the steaming. The above data provides a starting point for the design of processes at an industrial and gastronomic level.

The potential health benefits of legumes as a good source of dietary fibre.

Dietary fibre has been shown to have important health implications in the prevention of risks of chronic diseases. The objective of the present study was to determine the potential health benefits of legumes as a good source of dietary fibre. Six to ten local legumes were studied as follows: cowpeas, mung beans, pole sitao, chickpeas, green peas, groundnuts, pigeon peas, kidney beans, lima beans and soyabeans. The following studies were conducted: (a) mineral availability, in vitro; (b) glycaemic index (GI) in non-diabetic and diabetic human subjects; (c) the cholesterol-lowering effect in human subjects with moderately raised serum cholesterol levels. The highest Fe availability among legumes was for lima beans (9.5 (sem 0.1)) while for Zn and Ca, the highest availability was for kidney beans (49.3 (sem 4.5)) and pigeon peas (75.1 (sem 7.1)), respectively. Groundnuts have the lowest Fe (1.3 (sem 1.1)), Zn (7.9 (sem 1.3)) and Ca (14.6 (sem 2.8)) availability. Legumes are low-GI foods ( < 55), ranging from 6 (chickpeas) to 13 (mung beans). Kidney beans showed significant reductions for both total (6 %) and LDL-cholesterol (9 %), and groundnuts for total cholesterol (7 %; P < 0.05). We conclude that mineral availability from legumes differs and may be attributed to their mineral content, mineral-mineral interaction and from their phytic and tannic acid content; legumes are considered low-GI foods and have shown potential hypocholesterolaemic effects. The above studies can be a scientific basis for considering legumes as functional foods.

Back-scattered electron imaging and elemental analysis of retrieved bone tissue following sinus augmentation with deproteinized bovine bone or biphasic calcium phosphate.

OBJECTIVES: To compare resorption of a synthetic biphasic calcium phosphate (BCP) bone-graft substitute with deproteinized bovine bone (DBB) used for human maxillary sinus augmentation. MATERIALS AND METHODS: Eleven patients underwent bilateral maxillary sinus floor augmentation with DBB in one side and a BCP (40%beta-tricalcium phosphate (beta-TCP) and 60% hydroxyapatite) in the contralateral side. Simultaneously, with the augmentation on each side a microimplant was placed vertically from the top of the alveolar crest penetrating the residual bone and the grafting material. Eight months after initial surgery the microimplants were retrieved with a surrounding bone core. The composition of residual graft material and surrounding bone was analysed by scanning electron microscopy and energy dispersive X-ray spectroscopy. RESULTS: Residual graft material of both types was present as 10-500 mum particles in direct contact with, or completely surrounded by, newly formed bone; smaller particles were also present in non-mineralized tissue. In the case of BCP the bone-graft substitute interface showed evidence of superficial disintegration of particles into individual grains. Median Ca/P ratios (at.%), determined from >200 discreet sites within residual graft particles and adjacent bone, were: DBB: 1.61 (confidence interval [CI] 1.59-1.64); BCP: 1.5 (CI 1.45-1.52); DBB-augmented bone: 1.62 (CI 1.59-1.66); BCP-augmented bone: 1.52 (CI 1.47-1.55); P=0.028 for DBB vs. BCP and DBB- vs. BCP-augmented bone. The reduction in Ca/P ratio for BCP over the healing period is consistent with the dissolution of beta-TCP and reprecipitation on the surface of calcium-deficient hydroxyapatite. CONCLUSION: The beta-TCP component of BCP may be gradually substituted by calcium-deficient hydroxyapatite over the healing period. This process and superficial degranulation of BCP particles may influence the progress of resorption and healing.

Experimental model of intravitreal injection techniques.

PURPOSE: To evaluate the amount of drug reflux and vitreous leakage from the needle tract after various intravitreal (IVT) injection techniques in porcine cadaver eyes. METHODS: The reflux after IVT injection was quantified by methylene blue injection through the pars plana of fresh pig eyes (0.05 mL per eye, n = 150) and the vitreous incarceration measured after balanced salt solution (BSS) IVT injection (0.05 mL per eye, n = 150) into eyes with vitreous previously stained with methylene blue. Blue spots observed on the ocular surface after injection quantified both reflux and vitreous incarceration. We tested different needle sizes (27, 30, and 32 gauge) and different techniques (depth and speed of injection). We used an ocular endoscope to observe the flow and diffusion of injected methylene blue and the vitreous incarceration at the puncture site after IVT injection using the different techniques. RESULTS: Thirty-gauge needles showed less drug reflux than the 32-gauge or 27-gauge needles (P < 0.01). Thirty-two-gauge needles demonstrated less incarceration of vitreous at the tract site (P < 0.01), but with the endoscope, all needle tracts showed vitreous incarceration at their internal aspect. Deep IVT injection showed less reflux than superficial IVT injection, but vitreous incarceration did not differ. The delay between the scleral puncture and the injection did not modify the reflux or the vitreous incarceration. CONCLUSION: Thirty-gauge needles and deep placement of the needle tip into the vitreous before injection may reduce reflux and vitreous incarceration. This could maximize the therapeutic effect of IVT injection and may decrease the rates of severe complications such as retinal detachment and endophthalmitis.