Use of high-pressure processing and low-temperature storage to extend the performance shelf-life of two types of String cheese.

The manufacturing method of String cheese is similar to Mozzarella, but the hot curd is extruded through narrow tubes or pipes, which align the protein fibers that provides the characteristic ability for consumers to pull strings from this cheese. Firmness is another important performance attribute for consumers who just bite into the String cheese without peeling off strings. There have only been a few studies on String cheese, but it is known that stringiness and firmness decrease during prolonged storage, which is a particular challenge for exporting String cheese. We explored 2 treatments to try to retain the stringiness and firmness of String cheese for longer storage periods. The techniques used were high pressure processing (HPP; 600 MPa for 3 min) and reduced storage temperature (0°C). In other cheese varieties, these techniques have helped extend the performance shelf-life. We tested these techniques using the 2 main types of commercial String cheese: direct acid (DASC) and cultured String cheese (CSC), that were obtained from 2 different manufacturing facilities. The DASC had higher fat (∼2.2%) and higher pH values (∼0.2 units) compared with the CSC. The CSC had higher protein content (∼3.4%), higher insoluble calcium content (∼8 mg insoluble Ca/g protein) and higher hardness values (∼4 N) compared with the DASC. Due to the compositional differences, the 2 varieties were statistically analyzed separately for all other attributes. In both cheese types, HPP caused an immediate reduction in stringiness, some solubilization of insoluble calcium, and a slight increase in the cheese pH values. HPP also caused a slight increase in the TPA hardness of the CSC samples until 14 d (possibly due to a slight increase in cheese pH). The use of the 0°C storage temperature reduced proteolysis and helped retain firmness during storage. Low temperature storage could help extend the performance shelf-life of String cheese by a couple of months, but HPP was not suitable as the process caused an immediate reduction in stringiness due to the disruption of the matrix induced by the HPP treatment.

Field-cycling 31P and 1H NMR relaxometry studying the reorientational dynamics of glass forming organophosphates.

We apply field-cycling (FC) 31P nuclear magnetic resonance (NMR) to access the reorientational susceptibility of two glass formers, m-tricresyl phosphate (m-TCP) and tri-butyl phosphate (TBP). Although FC 31P studies are still instrumentally demanding, together with FC 1H data, they provide site-resolved information. A crossover from dipolar relaxation at low frequencies to relaxation determined by chemical shift anisotropy at high frequencies and probed by conventional NMR is identified. A comparison is made between dielectric (DS) and depolarized light scattering (DLS) relaxation spectra demonstrating similar behavior close to Tg, including an excess wing contribution for m-TCP. The time constants of 31P NMR and DLS, probing the molecular core, agree. The 1H data monitoring the dynamics of the phenyl groups yield slightly shorter correlation times. At high temperatures, the DS relaxation spectra show a bimodal character: a fast component in agreement with 1H data, and a slow component much slower than 31P NMR and DLS suggest. We discuss the possible origins of the slow component. All time constants tend to merge toward Tg. Hence, we propose that site-specific dynamics disappear and a common α-relaxation establishes near Tg. In addition, we compare the diffusion coefficient D(T) determined by FC and static field gradient 1H NMR. Concerning TBP, we present FC 31P data of both α- and ß-processes. Regarding the latter, we compare the DS and NMR susceptibility on absolute scale, yielding a significantly stronger ß-relaxation in the 31P NMR spectra.

Molecular dynamics simulations vs field-cycling NMR relaxometry: Structural relaxation mechanisms in the glass-former glycerol revisited.

We combine field-cycling (FC) relaxometry and molecular dynamics (MD) simulations to study the rotational and translational dynamics associated with the glassy slowdown of glycerol. The 1H NMR spin-lattice relaxation rates R1(ω) probed in the FC measurements for different isotope-labelled compounds are computed from the MD trajectories for broad frequency and temperature ranges. We find high correspondence between experiment and simulation. Concerning the rotational motion, we observe that the aliphatic and hydroxyl groups show similar correlation times but different stretching parameters, while the overall reorientation associated with the structural relaxation remains largely isotropic. Additional analysis of the simulation results reveals that transitions between different molecular configurations are slow on the time scale of the structural relaxation at least at sufficiently high temperatures, indicating that glycerol rotates at a rigid entity, but the reorientation is slower for elongated than for compact conformers. The translational contribution to R1(ω) is well described by the force-free hard sphere model. At sufficiently low frequencies, universal square-root laws provide access to the molecular diffusion coefficients. In both experiment and simulation, the time scales of the rotational and translational motions show an unusually large separation, which is at variance with the Stokes-Einstein-Debye relation. To further explore this effect, we investigate the structure and dynamics on various length scales in the simulations. We observe that a prepeak in the static structure factor S(q), which is related to a local segregation of aliphatic and hydroxyl groups, is accompanied by a peak in the correlation times τ(q) from coherent scattering functions.

BEESCOUT: A model of bee scouting behaviour and a software tool for characterizing nectar/pollen landscapes for BEEHAVE.

Social bees are central place foragers collecting floral resources from the surrounding landscape, but little is known about the probability of a scouting bee finding a particular flower patch. We therefore developed a software tool, BEESCOUT, to theoretically examine how bees might explore a landscape and distribute their scouting activities over time and space. An image file can be imported, which is interpreted by the model as a "forage map" with certain colours representing certain crops or habitat types as specified by the user. BEESCOUT calculates the size and location of these potential food sources in that landscape relative to a bee colony. An individual-based model then determines the detection probabilities of the food patches by bees, based on parameter values gathered from the flight patterns of radar-tracked honeybees and bumblebees. Various "search modes" describe hypothetical search strategies for the long-range exploration of scouting bees. The resulting detection probabilities of forage patches can be used as input for the recently developed honeybee model BEEHAVE, to explore realistic scenarios of colony growth and death in response to different stressors. In example simulations, we find that detection probabilities for food sources close to the colony fit empirical data reasonably well. However, for food sources further away no empirical data are available to validate model output. The simulated detection probabilities depend largely on the bees' search mode, and whether they exchange information about food source locations. Nevertheless, we show that landscape structure and connectivity of food sources can have a strong impact on the results. We believe that BEESCOUT is a valuable tool to better understand how landscape configurations and searching behaviour of bees affect detection probabilities of food sources. It can also guide the collection of relevant data and the design of experiments to close knowledge gaps, and provides a useful extension to the BEEHAVE honeybee model, enabling future users to explore how landscape structure and food availability affect the foraging decisions and patch visitation rates of the bees and, in consequence, to predict colony development and survival.

Association between clinical expression and molecular heterogeneity in ß-thalassemia Tunisian patients.

Beta-thalassemia is the most frequent hereditary blood disorder in Tunisia because of its geographic localization and history. This pathology is characterized by a complex multisystem process with genetic and biochemical interactions. The aim of this work was to establish phenotype/genotype association through studying the distribution and the relationship between ß-thalassemia and α-thalassemia mutations and three polymorphic markers: the C → T polymorphism at -158 of the Gγ gene, the RFLP haplotype and the repeated sequence (AT)xTy in the ß globin silencer, in two groups of ß-thalassemia major and ß-thalassemia intermedia (TI) patients. Statistical analysis has shown that moderate expression seen in TI patients was significantly associated to ß(+) -87 (C → G), -30 (T → A) and IVSI-6 (T → C) mutations, haplotypes VIII, IX and Nb and to XmnI polymorphism. The regression analysis of combined genotypes (mutation/XmnI/RFLP haplotype) revealed that they contribute to justify 17.1 % of clinical expression diversity (p < 0.05). Among the studied genotypes the XmnI polymorphism seems to be the most determinant modulating factor, followed by the ß-thalassemia mutation and RFLP haplotype. Our findings highlight the heterogeneity of molecular background of ß-thalassemia that would be responsible of clinical variability.

[Hypertriglyceridemic pancreatitis and cardiac tamponade in a 26-year-old woman]. / Hypertriglyzeridämie-bedingte Pankreatitis und Perikardtamponade bei einer 26­jährigen Patientin.

A 26-year-old woman with type 2 diabetes mellitus and discontinued intensive conventional insulin therapy was admitted to the authors' hospital with acute upper abdominal pain. Severe hypertriglyceridemia and acute pancreatitis were diagnosed. Treatment included insulin administration and plasmapheresis. On day 3, the patient developed sudden haemodynamic instability and in-hospital cardiopulmonary arrest. Focused echocardiography showed pericardial effusion with right ventricular collapse. Pericardiocentesis was performed, leading to a return of spontaneous circulation.

Nuclear Spin Relaxation in Viscous Liquids: Relaxation Stretching of Single-Particle Probes.

Spin-lattice relaxation rates R1(ω,T), probed via high-field and field-cycling nuclear magnetic resonance (NMR), are used to test the validity of frequency-temperature superposition (FTS) for the reorientation dynamics in viscous liquids. For several liquids, FTS is found to apply so that master curves can be generated. The susceptibility spectra are highly similar to those obtained from depolarized light scattering (DLS) and reveal an excess wing. Where FTS works, two approaches are suggested to access the susceptibility: (i) a plot of deuteron R1(T) vs the spin-spin relaxation rate R2(T) and (ii) a plot of R1(T) vs an independently measured reference time τref(T). Using single-frequency scans, (i) allows one to extract the relaxation stretching as well as the NMR coupling constant. Surveying 26 data sets, we find Kohlrausch functions with exponents 0.39 < ßK ≤ 0.67. Plots of the spin-spin relaxation rate R2─rescaled by the NMR coupling constant─as a function of temperature allow one to test how well site-specific NMR relaxations couple to a given reference process. Upon cooling of flexible molecule liquids, the site-specific dynamics is found to merge, suggesting that near Tg the molecules reorient essentially as a rigid entity. This presents a possible resolution for the much lower stretching parameters reported here at high temperatures that contrast with the ones that were reported to be universal in a recent DLS study close to Tg. Our analysis underlines that deuteron relaxation is a uniquely powerful tool to probe single-particle reorientation.

Regeneration of the vascular compartment.

Throughout life, damage to the vascular endothelium is pivotal in the development of cardiovascular disease. Therefore, a detailed understanding of the underlying mechanisms involved in endothelial cell restoration is of fundamental importance for preventive and therapeutic concepts in cardiovascular disease. The goal of regenerative medicine is the use of tissue-specific progenitor cells for a more effective repair process with reduction of fibrocellular remodelling, fibrosis and loss of functional properties.According to the hitherto assumed primary model of endothelial regeneration only adjacent and intact mature endothelial cells replace damaged endothelium. Since Asahara and colleagues first described that a peripheral blood mononuclear cell population was able to differentiate into endothelial cells in vitro and incorporate into ischemic tissue at sites of angiogenesis in vivo, the model of endothelial regeneration has been extended. The majority of clinical trials on human cell therapy for ischemic vascular disease are based on cell surface antigen expression of CD34 or VEGFR2 to identify endothelial progenitor cells.A precise characterization of the angiogenic properties of different subsets of endothelial regenerating cells and their course of action to gain sufficient long-term regeneration of the injured vessel is a necessary precondition before clinical trials of human cell therapy become a routine reality.

Neurofilament subunit NF-H modulates axonal diameter by selectively slowing neurofilament transport.

To examine the mechanism through which neurofilaments regulate the caliber of myelinated axons and to test how aberrant accumulations of neurofilaments cause motor neuron disease, mice have been constructed that express wild-type mouse NF-H up to 4.5 times the normal level. Small increases in NF-H expression lead to increased total neurofilament content and larger myelinated axons, whereas larger increases in NF-H decrease total neurofilament content and strongly inhibit radial growth. Increasing NF-H expression selectively slow neurofilament transport into and along axons, resulting in severe perikaryal accumulation of neurofilaments and proximal axonal swellings in motor neurons. Unlike the situation in transgenic mice expressing modest levels of human NF-H (Cote, F., J.F. Collard, and J.P. Julien. 1993. Cell. 73:35-46), even 4.5 times the normal level of wild-type mouse NF-H does not result in any overt phenotype or enhanced motor neuron degeneration or loss. Rather, motor neurons are extraordinarily tolerant of wild-type murine NF-H, whereas wild-type human NF-H, which differs from the mouse homolog at > 160 residue positions, mediates motor neuron disease in mice by acting as an aberrant, mutant subunit.

Evidence for cholinergic neurites in senile plaques.

In the neocortices and amygdalae of young and aged macaques, cholinergic axons were identified by means of a monoclonal antibody to bovine choline acetyltransferase. Many fine, linear, immunoreactive profiles were seen in these animals. In the older animals, some cholinergic axons showed multifocal enlargements along their course. In some instances, neurites with choline acetyltransferase immunoreactivity were associated with deposits of amyloid (visualized with thioflavin T fluorescence). The appearance of these amyloid-associated abnormal cholinergic processes was similar to that of neurites in senile plaques, as shown by conventional silver impregnation techniques. Cholinergic systems thus give rise to some of the neurites within senile plaques.

Ligand-dependent activation of the hedgehog pathway in glioma progenitor cells.

The hedgehog (Hh) signaling pathway regulates progenitor cells during embryogenesis and tumorigenesis in multiple organ systems. We have investigated the activity of this pathway in adult gliomas, and demonstrate that the Hh pathway is operational and activated within grade II and III gliomas, but not grade IV de novo glioblastoma multiforme. Furthermore, our studies reveal that pathway activity and responsiveness is confined to progenitor cells within these tumors. Additionally, we demonstrate that Hh signaling in glioma progenitor cells is ligand-dependent and provide evidence documenting the in vivo source of Sonic hedgehog protein. These findings suggest a regulatory role for the Hh pathway in progenitor cells within grade II and III gliomas, and the potential clinical utility of monitoring and targeting this pathway in these primary brain tumors.

ALS-linked SOD1 mutant G85R mediates damage to astrocytes and promotes rapidly progressive disease with SOD1-containing inclusions.

High levels of familial Amyotrophic Lateral Sclerosis (ALS)-linked SOD1 mutants G93A and G37R were previously shown to mediate disease in mice through an acquired toxic property. We report here that even low levels of another mutant, G85R, cause motor neuron disease characterized by an extremely rapid clinical progression, without changes in SOD1 activity. Initial indicators of disease are astrocytic inclusions that stain intensely with SOD1 antibodies and ubiquitin and SOD1-containing aggregates in motor neurons, features common with some cases of SOD1 mutant-mediated ALS. Astrocytic inclusions escalate markedly as disease progresses, concomitant with a decrease in the glial glutamate transporter (GLT-1). Thus, the G85R SOD1 mutant mediates direct damage to astrocytes, which may promote the nearly synchronous degeneration of motor neurons.

1H NMR at Larmor frequencies down to 3Hz by means of Field-Cycling techniques.

Field-Cycling (FC) NMR experiments were carried out at 1H Larmor frequencies down to about 3Hz. This could be achieved by fast switching a high polarizing magnetic field down to a low evolution field which is tilted with respect to the polarization field. Then, the low frequency Larmor precession of the nuclear spin magnetization about this evolution field is registered by means of FIDs in a high detection field. The crucial technical point of the experiment is the stabilization of the evolution field, which is achieved by compensating for temporal magnetic field fluctuations of all three spatial components. The paper reports on some other basic low field experiments such as the simultaneous measurement of the Larmor frequency and the spin-lattice relaxation time in such small fields as well as the irradiation of oscillating transversal magnetic field pulses at very low frequencies as a novel method for field calibration in low field FC NMR. The potential of low field FC is exemplified by the 1H relaxation dispersion of water at frequencies below about 2kHz stemming from the slow proton exchange process.

Perspectives of Deuteron Field-Cycling NMR Relaxometry for Probing Molecular Dynamics in Soft Matter.

Due to the single-particle character of the quadrupolar interaction in molecular systems, (2)H NMR poses a unique method for probing reorientational dynamics. Spin-lattice relaxation gives access to the spectral density, and its frequency dependency can be monitored by field-cycling (FC) techniques. However, most FC NMR studies employ (1)H; the use of (2)H is still rare. We report on the application of (2)H FC NMR for investigating the dynamics in molecular liquids and polymers. Commercial as well as home-built relaxometers are employed accessing a frequency range from 30 Hz to 6 MHz. Due to low gyromagnetic ratio, high coupling constants, and finite FC switching times, current (2)H FC NMR does not reach the dispersion region in liquids (toluene and glycerol), yet good agreement with the results from conventional high-field (HF) relaxation studies is demonstrated. The pronounced difference at low frequencies between (2)H and (1)H FC NMR data shows the relevance of intermolecular relaxation in the case of (1)H NMR. In the case of the polymers polybutadiene and poly(ethylene-alt-propylene), very similar relaxation dispersion is observed and attributed to Rouse and entanglement dynamics. Combination with HF (2)H relaxation data via applying frequency-temperature superposition allows the reconstruction of the full spectral density reflecting both polymer as well as glassy dynamics. Transformation into the time domain yields the reorientational correlation function C2(t) extending over nine decades in time with a long-time power law, C2(t) ∝ t(-0.45±0.05), which does not conform to the prediction of the tube-reptation model, for which ∝ t(-0.25) is expected. Entanglement sets in below C2(t = τe) ≅ S(2) = 0.001, where τe is the entanglement time and S the corresponding order parameter. Finally, we discuss the future prospects of the (2)H FC NMR technique.

The neuropathology of CAG repeat diseases: review and update of genetic and molecular features.

Classification of inherited neurodegenerative diseases is increasingly based on their genetic features, which supplement, clarify, and sometimes replace the older clinical and pathologic schemata. This change has been particularly rapid and impressive for the CAG repeat disorders. In Huntington's disease, X-linked spinobulbar muscular atrophy, dentatorubropallidoluysian atrophy, and a series of autosomal dominant cerebellar atrophies, genetic advances have resolved many nosologic issues, and opened new avenues for exploration of pathogenesis. In this review, we summarize classic and current concepts in neuropathology of these CAG repeat diseases.

Huntington's disease and dentatorubral-pallidoluysian atrophy: proteins, pathogenesis and pathology.

Each of the glutamine repeat neurodegenerative diseases has a particular pattern of pathology largely restricted to the CNS. However, there is considerable overlap among the regions affected, suggesting that the diseases share pathogenic mechanisms, presumably involving the glutamine repeats. We focus on Huntington's disease (HD) and Dentatorubral-pallidoluysian atrophy (DRPLA) as models for this family of diseases, since they have striking similarities and also notable differences in their clinical features and pathology. We review the pattern of pathology in adult and juvenile onset cases. Despite selective pathology, the disease genes and their protein products (huntingtin and atrophin-1) are widely expressed. This presents a central problem for all the glutamine repeat diseases-how do widely expressed gene products give rise to restricted pathology? The pathogenic effects are believed to occur via a "gain of function" mechanism at the protein level. Mechanisms of cell death may include excitotoxicity, metabolic toxicity, apoptosis, and free radical stress. Emerging data indicate that huntingtin and atrophin-1 may have distinct protein interactions. The specific interaction partners may help explain the selective pathology of these diseases.

Inherited neurodegenerative diseases and transgenic models.

In recent years, the identification of mutations in specific genes in several inherited neurodegenerative disorders, combined with advances in the field of transgenic methods, has provided neuroscientists and neuropathologists with information and strategies to develop transgenic (Tg) models to study human diseases. These approaches have proved to be extraordinarily useful in modeling familial forms of amyotrophic lateral sclerosis (FALS) and Alzheimer's disease (FAD) and the spectrum of triplet-repeat disorders. Investigations of these models have begun to provide new insights into the roles of disease-specific mutant proteins and the pathogenic mechanisms of disease as well as opportunities to test therapeutic interventions.

Patients with features similar to Huntington's disease, without CAG expansion in huntingtin.

OBJECTIVE: To describe characteristics of gene-negative patients with clinical features of Huntington's disease (HD), exploring likely etiologies. BACKGROUND: When a direct gene test became definitive for diagnosis of HD, we discovered a number of patients in our clinics in Baltimore, MD, and Cambridge, UK, believed or suspected to have HD who did not have the triplet repeat expansion. METHODS: Patients were examined using standardized instruments, and given full neurologic and psychiatric evaluations. Those negative for HD were tested for dentatorubro-pallidoluysian atrophy, SCA-1, SCA-3, SCA-2, SCA-6, and other conditions as indicated. RESULTS: Of 15 patients, 7 received specific diagnoses or appear to be sporadic cases, 4 have a possible but uncertain relation to HD, and 4 have unknown familial progressive movement disorders. CONCLUSIONS: This last group of patients might be properly described as phenocopies of HD, some of which may be caused by unidentified triplet repeat expansions.

Anomalous right coronary artery associated with sudden death: an example of a neural crest migration defect.

A unique right coronary artery anomaly of hemodynamic significance was discovered in a young adult who suddenly died. In addition, abnormally migrated, or supernumerary, thymic tissue with embedded parathyroid glands was present. This combination of congenital malformations suggests that the pathogenesis of this rare cardiac anomaly may be explained by a cranial neural crest defect.

Kearns-Sayre syndrome with features of Pearson's marrow-pancreas syndrome and a novel 2905-base pair mitochondrial DNA deletion.

Kearns-Sayre syndrome (KSS) and Pearson's marrow-pancreas syndrome (PMPS) are rare disorders caused by the same molecular defect, one of several deletion mutations in mitochondrial DNA (mtDNA). KSS is an encephalomyopathy with ophthalmoplegia, retinal degeneration, ataxia, and endocrine abnormalities. PMPS is a disorder of childhood characterized by refractory anemia, vacuolization of bone marrow cells, and exocrine pancreas dysfunction. Children with PMPS that have a mild phenotype, or are supported through bone marrow failure, often develop the encephalomyopathic features of KSS. The subject of numerous reports in the neuromuscular, genetic, and pediatric literature in recent years, very few cases of either disorder have ever been studied at autopsy. We report the results of our studies of a patient with clinically documented KSS who presented with renal dysfunction and was found to have a novel mtDNA deletion and degenerative changes in the central nervous system, retina, skeletal muscle, and pancreas.