The affinity of milk fat globule membrane fragments and buttermilk proteins to hydroxyapatite.

Buttermilk differs from skim milk by the presence of milk fat globule membrane (MFGM) fragments that are released during cream churning. Milk fat globule membrane is rich in health-promoting components, such as phospholipids and membrane proteins, but these compounds have a negative impact on buttermilk techno-functional properties in dairy applications. The isolation of MFGM from buttermilk improved its functionality while also recovering the MFGM bioactive components. Hydroxyapatite (HA) can be used to extract MFGM by adsorption via charged site interactions. However, the affinity of HA to MFGM or the main buttermilk proteins (casein micelles [CM], ß-LG, and α-LA) is not known. The influence of important physicochemical parameters such as pH and temperature on these interactions is also unclear. For each buttermilk component, a quartz crystal microbalance diffusion analysis was performed to determine the maximum adsorption time and the attached mass density on HA-coated gold sensors. The influence of pH, ionic strength (IS), and temperature (T) on the affinity of each buttermilk component for HA particles was assessed using a 3-levels and 3-factors Box-Behnken design. The absorption rate was highest for the CM, followed by ß-LG and α-LA, and then by the MFGM. Nevertheless, the final maximal attached mass densities to the HA were similar for the MFGM and CM, and 2.5 times higher than for ß-LG and α-LA. This difference can be explained by the higher number of binding sites found in CM and their heavier mass. The model obtained by the Box-Behnken design plan showed that the adsorption of the CM changed with T, pH, and IS. These results suggest that the techno-functional properties of buttermilk may be restored by specifically extracting MFGM with HA. Experiments are ongoing to determine conditions for fractionating MFGM directly from buttermilk.

Effect of reverse osmosis and ultra-high-pressure homogenization on the composition and microstructure of sweet buttermilk.

Buttermilk (BM), the by-product of butter making, is similar to skim milk (SM) composition. However, it is currently undervalued in dairy processing because it is responsible for texture defects (e.g., crumbliness, decreased firmness) in cheese and yogurt. One possible way of improving the incorporation of BM into dairy products is by the use of technological pretreatments such as membrane filtration and homogenization. The study aimed at characterizing the effect of preconcentration by reverse osmosis (RO) and single-pass ultra-high-pressure homogenization (UHPH) on the composition and microstructure of sweet BM to modify its techno-functional properties (e.g., protein gel formation, syneresis, firmness). The BM and RO BM were treated at 0, 15, 150, and 300 MPa. Pressure-treated and control BM and RO BM were ultracentrifuged to fractionate them into the following 3 fractions: a supernatant soluble fraction (top layer), a colloidal fraction consisting of a cloudy layer (middle layer), and a high-density pellet (bottom layer). Compositional changes in the soluble fraction [lipid, phospholipid (PL), protein, and salt], as well as its protein profile by PAGE analysis, were determined. Modifications in particle size distribution upon UHPH were monitored by laser diffraction in the presence and absence of sodium citrate to dissociate the casein (CN) micelles. Microstructural changes in pressure-treated and non-pressure-treated BM and RO BM particles were monitored by confocal laser scanning microscopy. Particle size analysis showed that UHPH treatment significantly decreased the size of the milk fat globule membrane fragments in BM and RO BM. Also, pressure treatment at 300 MPa led to a significant increase in the recovery of total lipids, CN, calcium, and phosphate in the BM soluble fraction (top layer) following ultracentrifugation. However, PL were primarily concentrated in the pellet cloud (middle layer), located above the pellet in BM concentrated by RO. In contrast, PL were evenly distributed between soluble and colloidal phases of BM. This study provides insight into the modifications of sweet BM constituents induced by RO and UHPH from a compositional and structural perspective.

Effect of alkalinization and ultra-high-pressure homogenization on casein micelles in raw and pasteurized skim milk.

Mechanical and physicochemical treatments of milk induce structural modifications of the casein (CN) micelles, affecting their techno-functional properties in dairy processing. Here, we studied the effect of alkalinization and ultra-high-pressure homogenization (UHPH) on CN micelles in raw skim milk (rSM) and pasteurized skim milk (pSM). The pH of both skim milks (approximately 6.7) was adjusted to 8.5 and 10.5 before UHPH at 100, 200, and 300 MPa. The structural changes of the CN micelles during the treatments were assessed using laser diffraction, transmission electron microscopy, and turbidity measurements. Finally, ultracentrifugation (70,000 × g for 1 h at 20°C) was carried out to evaluate the protein's distribution between the supernatant (serum phase) and the pellet (colloidal phase) by gel electrophoresis and protein concentration measurement. Alkalinization of both skim milks induced a significant reduction in turbidity, whereas an increase of the average particle size was observed, the effect being more severe in pSM than rSM. At alkaline pH, more proteins were recovered in the serum phase, which suggested that the CN underwent major rearrangements into nonsedimentable CN forms of various sizes, as confirmed by transmission electron microscopy. The amount of CN found in the serum phase at pH 8.5 also increased with the UHPH pressure. Although UHPH did not influence the average CN micelle size at pH 6.7 and 8.5, a pressure-dependent decrease was observed at pH 10.5 for both skim milks. The structural changes of the CN micelles observed in this study throughout the combination of alkalinization and UHPH could be of interest for developing new dairy ingredients with improved functionality.

Preparation of milk protein concentrates by ultrafiltration and continuous diafiltration: Effect of process design on overall efficiency.

High-milk-protein concentrates (>80% on a dry weight basis) are typically produced by ultrafiltration (UF) with constant-volume diafiltration (DF). To maximize protein retention at a commercial scale, polymeric spiral-wound UF membranes with a molecular weight cut-off (MWCO) of 10 kDa are commonly used. Flux decline and membrane fouling during UF have been studied extensively and the selection of an optimal UF-DF sequence is expected to have a considerable effect on both the process efficiency and the volumes of by-products generated. The objective of this study was to characterize the performance of the UF-DF process by evaluating permeate flux decline, fouling resistance, energy and water consumption, and retentate composition as a function of MWCO (10 and 50 kDa) and UF-DF sequence [3.5×-2 diavolumes (DV) and 5×-0.8DV]. The UF-DF experiments were performed on pasteurized skim milk using a pilot-scale filtration system operated at 50°C under a constant transmembrane pressure of 465 kPa. The results showed that MWCO had no effect on permeate flux for the same UF-DF sequence. Irreversible resistance was also similar for both sequences, whatever the MWCO, suggesting that soluble protein deposition within the pores is similar for all conditions. Despite lower permeate fluxes and greater reversible resistance for the 5×-0.8DV sequence, the overall energy consumption of the 2 UF-DF sequences was similar. However, the 3.5×-2DV sequence required more water for DF and generated larger volumes of permeate to be processed, which will require more membrane area and lead to greater environmental impact. A comparative life cycle assessment should however be performed to confirm which sequence has the lowest environmental impact.

Process efficiency of casein separation from milk using polymeric spiral-wound microfiltration membranes.

Microfiltration is largely used to separate casein micelles from milk serum proteins (SP) to produce a casein-enriched retentate for cheese making and a permeate enriched in native SP. Skim milk microfiltration is typically performed with ceramic membranes and little information is available about the efficiency of spiral-wound (SW) membranes. We determined the effect of SW membrane pore size (0.1 and 0.2 µm) on milk protein separation in total recirculation mode with a transmembrane pressure gradient to evaluate the separation efficiency of milk proteins and energy consumption after repeated concentration and diafiltration (DF). Results obtained in total recirculation mode demonstrated that pore size diameter had no effect on the permeate flux, but a drastic loss of casein was observed in permeate for the 0.2-µm SW membrane. Concentration-DF experiments (concentration factor of 3.0× with 2 sequential DF) were performed with the optimal 0.1-µm SW membrane. We compared these results to previous data we generated with the 0.1-µm graded permeability (GP) membrane. Whereas casein rejection was similar for both membranes, SP rejection was higher for the 0.1-µm SW membrane (rejection coefficient of 0.75 to 0.79 for the 0.1-µm SW membrane versus 0.46 to 0.49 for the GP membrane). The 0.1-µm SW membrane consumed less energy (0.015-0.024 kWh/kg of permeate collected) than the GP membrane (0.077-0.143 kWh/kg of permeate collected). A techno-economic evaluation led us to conclude that the 0.1-µm SW membranes may represent a better option to concentrate casein for cheese milk; however, the GP membrane has greater permeability and its longer lifetime (about 10 yr) potentially makes it an interesting option.

Effect of transmembrane pressure control on energy efficiency during skim milk concentration by ultrafiltration at 10 and 50°C.

The efficiency of the ultrafiltration process during skim milk concentration was studied using both dynamic and constant (465 or 672kPa) transmembrane pressure experiments at refrigerated temperature (10°C) and high temperature (50°C). The pilot-scale module was equipped with a 10-kDa polyethersulfone spiral-wound membrane element with a surface area of 2.04m2. Permeation flux, resistance-in-series model, mineral and protein rejection, and energy consumption were studied as a function of temperature and transmembrane pressure applied. Higher permeation flux values were systematically obtained at 50°C. Also, a significant temperature effect was found for calcium rejection, which was lower at 10°C compared with 50°C. Total hydraulic resistance and reversible fouling resistance were higher at 50°C than at 10°C. No change in protein rejection was observed, depending on the operating mode studied. Permeation flux, which was higher at 50°C, had lower pumping energy consumption compared with ultrafiltration at the colder temperature. Also, the low ultrafiltration temperature required a higher total energy consumption to reach the 3.6× retentate compared with ultrafiltration at 50°C. Overall, our study shows that the operating parameters and temperature can be optimized using an energy efficiency ratio.

A process efficiency assessment of serum protein removal from milk using ceramic graded permeability microfiltration membrane.

Microfiltration (MF) is a well-known process that can be used in the dairy industry to separate caseins from serum proteins (SP) in skim milk using membranes with a pore diameter of 0.1µm. Graded permeability ceramic membranes have been studied widely as means of improving milk fractionation by overcoming problems encountered with other MF membranes. The ideal operating parameters for process efficiency in terms of membrane selectivity, permeate flux, casein loss, SP transmission, energy consumption, and dilution with water remain to be determined for this membrane. Our objective was to evaluate the effects of transmembrane pressure (TMP), volumetric concentration factor (VCF), and diafiltration on overall process efficiency. Skim milk was processed using a pilot-scale MF system equipped with 0.72-m(2) graded permeability membranes with a pore size of 0.1µm. In the first experiment, in full recycle mode, TMP was set at 124, 152, 179, or 207 kPa by adjusting the permeate pressure at the outlet. Whereas TMP had no significant effect on permeate and retentate composition, 152 kPa was found to be optimal for SP removal during concentration and concentration or diafiltration experiments. When VCF was increased to 3×, SP rejection coefficient increased along with energy consumption and total casein loss, whereas SP removal rate decreased. Diafiltering twice allowed an increase in total SP removal but resulted in a substantial increase in energy consumption and casein loss. It also reduced the SP removal rate by diluting permeate. The membrane surface area required for producing cheese milk by blending whole milk, cream, and MF retentate (at different VCF) was estimated for different cheese milk casein concentrations. For a given casein concentration, the same quantity of permeate and SP would be produced, but less membrane surface area would be needed at a lower retentate VCF. Microfiltration has great potential as a process of adding value to conventional cheesemaking processes, but its cost-effectiveness at a large scale remains to be demonstrated.

Chronic inflammation of upper airways in children: basic principles.

PROBLEMS/OBJECTIVES: A child's immune system has to initiate the immune response from scratch and cannot depend on a memory-type of immune response. Moreover, the immune system in newborns is also less efficient in inducing cytokine responses. In consequence, newborns and children are more susceptible to upper-airway infections and inflammation than adults. This manuscript summarises basic considerations relating to immune and inflammatory response in the upper airways and presents data about the processes involved in immunity development and maturation in children. METHOD: Literature review. RESULTS: Inflammation is a complex set of interactions between soluble factors and cells that can arise in any tissue in response to both exogenous (infectious, toxic...) and endogenous (auto-immune, ischaemia...) insults. It interacts actively with the adaptive immune response by launching the antigen processing and presenting phases. Reduced cytotoxic response during foetal life, poor T-lymphocyte response to mitogens, immaturity of T and B lymphocytes, inadequate cytokine synthesis, a marked deficiency of antibody production and reduced neutrophil, complement and natural killer activity are important contributors to the complex physiological deficiency of immunological function in neonates and young children. CONCLUSIONS: The importance of the control and self-limitation of the inflammatory reaction is demonstrated by observations that, in certain chronic infectious or inflammatory conditions, the inflammatory response causes more damage to the host than the microbe.

Biological conditions affecting chronic inflammation in upper airways in children.

PROBLEMS/OBJECTIVES: A child's immune system cannot depend on a memory-type immune response and it also induces cytokine responses less efficiently. Biological conditions like allergy or cystic fibrosis, immune deficiency or gastrooesophageal reflux can induce and maintain background inflammation in children's upper airways, making newborns and children more susceptible to upper airway infections and inflammations. This paper will describe in brief how allergy, cystic fibrosis, immune deficiency, nasal and paranasal anatomical variants, and gastro-oesophageal reflux (GOR) can affect the immune and inflammatory responses in upper airways and how they could interfere with immunity development and maturation in children. METHODOLOGY: Literature review. RESULTS: Chronic inflammation induced by infection, allergy, cystic fibrosis or immune deficiency is multifactorial in origin and is strongly influenced by physiological, immunological, anatomical, environmental and, above all, genetic parameters. Finally, the direct role played by nasal and paranasal anatomical variants and GOR is also discussed. CONCLUSIONS: These conditions should be screened systematically in all children presenting chronic clinical features of upper airway inflammation.

Midline crossing: developmental trend from 3 to 10 years of age in a preferential card-reaching task.

We assessed 110 left-handed and 322 right-handed children aged from 3 to 10 years, using Bishop's card-reaching task. Manual body midline crossings were observed. A regular developmental trend was observed from 3 to 10 years: older children crossed the body midline more frequently when reaching for cards than did younger children. The factor age explained 4.9% of the variance. Significant differences appeared between 3-4 years old children and 8-10 years old children. The effect of the spatial position of the cards was also significant: the contralateral hand was used less often to reach cards at the most extreme positions. These findings in this task demonstrate that the development of the degree of handedness follows a long developmental trend.

Universal newborn hearing screening.

Hearing loss is one of the most common congenital anomalies, occurring in approximately 1-2 infants per 1000. Left undetected, hearing impairments in infants can negatively impact speech and language acquisition, academic achievement, social and emotional development. These negative impacts can be diminished and even eliminated through early intervention at or before 6 months of age. Reliable screening tests that minimize referral rates and maximize sensitivity and specificity are available. The goal of universal neonatal hearing screening is to maximize linguistic and communicative competence and literacy development for children who are hard of hearing or deaf. Audiologic and medical evaluations should be in progress before 3 months of age. Infants with confirmed hearing loss should receive intervention before 6 months of age from health care and education professionals with expertise in hearing loss and deafness in infants and young children.

Hepatocyte nuclear factor 1alpha controls the expression of terminal complement genes.

The terminal components of the complement system contribute to host defense by forming the multiprotein membrane attack complex (MAC) which is responsible for cell lysis and several noncytotoxic effects. Most of the complement proteins are synthesized in the liver, but the mechanisms controlling their tissue-specific expression have not been elucidated. In this study we show that mice lacking the hepatic transcription factor hepatocyte nuclear factor 1alpha (HNF1alpha) fail to transcribe C5 and C8A complement genes. In addition, mRNAs encoding for several other terminal complement components or subunits are expressed at lower levels, including C8beta, C8gamma, and C9. We next used a reconstitution assay involving human sera with selective complement deficiencies to assess mouse complement activity. Sera from HNF1alpha-deficient mice showed negligible hemolytic activity of both C5 and C8alpha-gamma subunits. The activity of C8beta was severely affected despite only a 50% reduction in C8beta mRNA levels in the liver. This is reminiscent of C8alpha-gamma-deficient patients who accumulate extremely low levels of the C8beta subunit. Our results demonstrate that HNF1alpha plays a key role in the expression of C5 and C8A genes, two terminal complement component genes that are essential for the assembly of MAC as a result of complement activation.

What can be learned from a lattice analysis of a laterality questionnaire?

In order to develop a genetic study of human laterality, we conducted an exploratory study concerning one aspect of this phenotype: lattice analysis was used to determine whether the structure of manual preference was the same for right- and left-handers. The study highlights the links between two sets - participants and actions - describing binary data, by ordering them "dually" along a "Galois lattice": participants were ordered according to subsets of actions for which they used only their writing hand, while actions were ordered according to sub-groups using their writing hand to perform them. The twelve item questionnaire of Annett was analysed in two samples of 94 adult right-hand and 31 left-hand writers. The items did not have the same categorical impact for the two groups of left- and right-hand writers. The behaviour of right-handers appeared globally more stereotyped. On the contrary, left-handed profiles were nearly all distinct. To explore these conclusions more thoroughly in the general population would certainly require greater samples. Nevertheless in both cases the observed structures were highly dimensional, a result that would grow stronger as the group sizes increase. Hence whereas some questionnaires purport to evaluate laterality along an unidimensional continuum, the present analysis questions such a strong assumption providing evidence to the contrary.

HNF1alpha controls renal glucose reabsorption in mouse and man.

Recently it has been shown that dominant mutations in the human hepatocyte nuclear factor 1alpha (HNF1alpha) gene, encoding for a homeoprotein that is expressed in liver, kidney, pancreas and intestine, result in maturity onset diabetes of the young type 3 (MODY3). HNF1alpha-null mice are diabetic, but at the same time suffer from a renal Fanconi syndrome characterized by urinary glucose loss. Here we show that MODY3 patients are also characterized by a reduced tubular reabsorption of glucose. The renal murine defect is due to reduced expression of the low affinity/high capacity glucose cotransporter (SGLT2). Our results show that HNF1alpha directly controls SGLT2 gene expression. Together these data indicate that HNF1alpha plays a key role in glucose homeostasis in mammals.

Defective insulin secretion in hepatocyte nuclear factor 1alpha-deficient mice.

Mutations in the gene for the transcription factor hepatocyte nuclear factor (HNF) 1alpha cause maturity-onset diabetes of the young (MODY) 3, a form of diabetes that results from defects in insulin secretion. Since the nature of these defects has not been defined, we compared insulin secretory function in heterozygous [HNF-1alpha (+/-)] or homozygous [HNF-1alpha (-/-)] mice with null mutations in the HNF-1alpha gene with their wild-type littermates [HNF-1alpha (+/+)]. Blood glucose concentrations were similar in HNF-1alpha (+/+) and (+/-) mice (7.8+/-0.2 and 7.9+/-0.3 mM), but were significantly higher in the HNF-1alpha (-/-) mice (13.1+/-0.7 mM, P < 0.001). Insulin secretory responses to glucose and arginine in the perfused pancreas and perifused islets from HNF-1alpha (-/-) mice were < 15% of the values in the other two groups and were associated with similar reductions in intracellular Ca2+ responses. These defects were not due to a decrease in glucokinase or insulin gene transcription. beta cell mass adjusted for body weight was not reduced in the (-/-) animals, although pancreatic insulin content adjusted for pancreas weight was slightly lower (0.06+/-0.01 vs. 0.10+/-0.01 microg/mg, P < 0.01) than in the (+/+) animals. In summary, a null mutation in the HNF-1alpha gene in homozygous mice leads to diabetes due to alterations in the pathways that regulate beta cell responses to secretagogues including glucose and arginine. These results provide further evidence in support of a key role for HNF-1alpha in the maintenance of normal beta cell function.

Hepatocyte nuclear factor 1alpha gene inactivation impairs chromatin remodeling and demethylation of the phenylalanine hydroxylase gene.

Hepatocyte nuclear factor 1 alpha (HNF1alpha) is a homeoprotein that is expressed in the liver, kidney, pancreas, and digestive tract. Its inactivation in mouse resulted in decreased transcription of known target genes such as albumin and alpha1-antitrypsin. In contrast, the phenylalanine hydroxylase (PAH) gene was totally silent and unresponsive to normal inducers like glucocorticoids and cyclic AMP in the liver. DNase I and micrococcal nuclease digestion of liver nuclei showed that HNF1alpha inactivation had drastic effects on the chromatin structure of the PAH regulatory regions. Three DNase I-hypersensitive sites (HSSI, HSSII, and HSSIII), typical of the actively transcribed PAH gene, were undetectable in liver from HNF1alpha-deficient animals. Both HSSII and HSSIII elements harbor HNF1 sites, but only the latter has detectable enhancer activity in transient-transfection assays. In addition, the PAH promoter in livers of HNF1alpha-deficient animals was methylated. These results suggest that HNF1alpha could activate transcription through two mechanisms. One implies participation in the recruitment of the general transcription machinery to the promoter, and the second involves the remodeling of chromatin structure and demethylation that would allow transcription factors to interact with their cognate cis-acting elements.

Triosite implants and fibrin glue in the treatment of atrophic rhinitis: technique and results.

Nine patients with primary or secondary atrophic rhinitis were treated by narrowing of the nasal fossae using a new surgical technique (derived from the Eryes procedure) in which a Triosite and fibrin glue mixture is implanted via the labial vestibule route. The results were good or excellent in seven patients. No rejections occurred. Osseocoalescence, as evaluated by computed axial tomography at 6 months, was good. Inspiratory intrasnasal pain in patients with postsurgical atrophic rhinitis improved following the operation. The surgical technique, which is quick and easy to perform, avoids the discomfort of nostril closure or the implantation of grafts from other parts of the body. Complicated flap procedures are also avoided.

Hepatocyte nuclear factor 1 inactivation results in hepatic dysfunction, phenylketonuria, and renal Fanconi syndrome.

HNF1 is a transcriptional activator of many hepatic genes including albumin, alpha1-antitrypsin, and alpha- and beta-fibrinogen. It is related to the homeobox gene family and is predominantly expressed in liver and kidney. Mice lacking HNF1 fail to thrive and die around weaning after a progressive wasting syndrome with a marked liver enlargement. The transcription rate of genes like albumin and alpha1-antitrypsin is reduced, while the gene coding for phenylalanine hydroxylase is totally silent, giving rise to phenylketonuria. Mutant mice also suffer from severe Fanconi syndrome caused by renal proximal tubular dysfunction. The resulting massive urinary glucose loss leads to energy and water wasting. HNF1-deficient mice may provide a model for human renal Fanconi syndrome.

[Exudative laryngeal diseases of Reinke's space]. / Laryngopathies exsudatives de l'espace de Reinke.

Exudative laryngopathies are represented by the nodule, the polyp and the Reinke's oedema. Their origin is found in exudative processes located in the Reinke's space. Evolution towards one or another lesion depends on the etiological factor (vocal abuse, tobacco, alcohol, acute vocal fold trauma) and can happen according three modalities: oedema, fibrosis and angiectasies development. Apparition of fibrosis inside the lesion or too important haemorrhage require microsurgical treatment in addition to the medical treatment and the speech therapy.