Short-term changes in soil pore size distribution: Impact of land use

Changes in land use affect the pore size distribution (PSD) of the soil, and hence important soil functions such as gas exchange, water availability and plant growth. The objective of this study was to investigate potentially damaging and restorative soil management practices on soil pore structure. We quantified the rate of change in PSD six years after changes in land use taking advantage of the Highfield land-use change experiment at Rothamsted Research. This experiment includes short-term soil degradation and restoration scenarios established simultaneously within long-term contrasting treatments that had reached steady-state equilibrium. The land-use change scenarios comprised conversion to grassland of previously arable or bare fallow soil, and conversion of grassland to arable and bare fallow soils. In the laboratory, we exposed intact soil cores (100 cm3) to matric potentials ranging from -10 hPa to -1.5 MPa. Based on equivalent soil mass, the plant available water capacity decreased after conversion from grassland, whereas no change was observed after conversion to grassland. Structural void ratio decreased after termination of grassland and introduction of grassland in bare fallow soil, while no change was seen when changing arable to grassland. Consequently, it was faster to degrade than to restore a complex soil structure. The study illustrates that introducing grassland in degraded soil may result in short-term increase in soil density.

Soil degradation and recovery - Changes in organic matter fractions and structural stability

The combination of concurrent soil degradation and restoration scenarios in a long-term experiment with contrasting treatments under steady-state conditions, similar soil texture and climate make the Highfield land-use change experiment at Rothamsted Research unique. We used soil from this experiment to quantify rates of change in organic matter (OM) fractions and soil structural stability (SSS) six years after the management changed. Soil degradation included the conversion of grassland to arable and bare fallow management, while soil restoration comprised introduction of grassland in arable and bare fallow soil. Soils were tested for clay dispersibility measured on two macro-aggregate sizes (DispClay 1-2 mm and DispClay 8-16 mm) and clay-SOM disintegration (DI, the ratio between clay particles retrieved without and with SOM removal). The SSS tests were related to soil organic carbon (SOC), permanganate oxidizable C (POXC) and hot water-extractable C (HWC). The decrease in SOC after termination of grassland was greater than the increase in SOC when introducing grassland. In contrast, it was faster to restore degraded soil than to degrade grassland soil with respect to SSS at macro-aggregate scale. The effect of management changes was more pronounced for 8-16 mm than 1-2 mm aggregates indicating a larger sensitivity towards tillage-induced breakdown of binding agents in larger aggregates. At microscale, SSS depended on SOC content regardless of management. Soil management affected macroscale structural stability beyond what is revealed from measuring changes in OM fractions, underlining the need to include both bonding and binding mechanisms in the interpretation of changes in SSS induced by management.

Soil organic matter widens the range of water contents for tillage

The effects of soil organic matter on the water contents for tillage were investigated by sampling soils with a uniform texture, but a range of soil organic carbon (SOC) from two long-term field experiments at Highfield in Rothamsted Research, UK and Askov Experimental Station, Denmark. The treatments studied in Highfield were Bare fallow (BF), Continuous arable rotation (A), Ley-arable (LA) and Grass (G); and in Askov: unfertilized (UNF), ½ mineral fertilizer (½ NPK), 1 mineral fertilizer (1NPK), and 1½ animal manure (1½AM). Minimally disturbed soil cores (100 cm3) were sampled per plot in both locations from 6 to 10 cm depth to generate water retention data. Soil blocks were also sampled at 6-15 cm depth to determine basic soil properties and to measure soil aggregate strength parameters. The range of soil water contents appropriate for tillage were determined using the water retention and the consistency approaches. SOC content in Highfield was in the order: G > LA = A > BF, and in Askov: 1½ AM > 1NPK = ½NPK > UNF. Results showed that different long-term management of the silt loam Highfield soil, and fertilization of the sandy loam Askov soil affected the mechanical properties of the soils- for Highfield soil, aggregates from the G treatment were stronger in terms of rupture energy when wet (-100 hPa matric potential) than the BF treatment. As the soil dried (-300 and -1000 hPa matric potentials), soil aggregates from the G treatment were relatively weaker and more elastic than the BF soil. Our study showed, for both Highfield and Askov soils, a strong positive linear increase in the range of water contents for tillage with increasing contents of SOC. This suggests that management practices leading to increased SOC can improve soil workability by increasing the range of water contents for tillage. We recommended using the consistency approach over the water retention approach for determining the range of water contents for tillage because it seems to give realistic estimates of the water contents for tillage.

Possible Utility of Serum Determinations of CA 125 and CA 27.29 in Breast Cancer Management

The utility of measurement of serum levels of the tumor associated antigens CA 125 and CA 27.29 in detecting the presence of disease and in monitoring changes in disease status was examined in 63 patients with breast cancer. In patients with clinically detectable disease the CA 125 level was elevated in 59%, the CA 27.29 level in 59.5% and one or both markers in 84.6%. Specificity for presence of disease was 83.6% for CA 125, 88% for CA 27.29, and 69.1% for the two markers combined. Changes in marker levels of more than 50% correlated with clinical changes in disease status in 58% of cases for either CA 125 or CA 27.29 alone. In 87.5% of cases with clinically progressive disease one or both marker levels increased by more than 50% from the previous levels. In no case with greater than 50% increase in a marker level was there regression of disease. Thus, the use of these markers in combination might have utility in cases where diagnosis of recurrent disease is difficult or where monitoring of response to treatment is hampered by lack of measurable disease.

Cherubism: panoramic and CT features in adults

OBJECTIVES

To describe the panoramic radiographic and CT features of cherubism in an unselected series of 15 adults.

METHODS

In this cross-sectional study, 15 individuals aged 29-84 years with familial non-syndromal molecularly confirmed cherubism were examined with panoramic radiography and CT. Bone abnormalities were analysed and described.

RESULTS

11 (73%) of the 15 adults had mandibular abnormalities. These abnormalities ranged from subtly detectable to severe, and were less prevalent and expansive but could be rather similar to the characteristic image features in children. Unilocular radiolucencies were more common than multilocular radiolucencies, and a specific feature of these abnormalities was that they were exclusively found in the anterior mandible.

CONCLUSIONS

The radiographic and CT abnormalities of cherubism in adults were frequent and extremely heterogeneous, with some distinct features.

Task specialization in two social spiders, Stegodyphus sarasinorum (Eresidae) and Anelosimus eximius (Theridiidae)

Understanding the social organization of group-living organisms is crucial for the comprehension of the underlying selective mechanisms involved in the evolution of cooperation. Division of labour and caste formation is restricted to eusocial organisms, but behavioural asymmetries and reproductive skew is common in other group-living animals. Permanently, social spiders form highly related groups with reproductive skew and communal brood care. We investigated task differentiation in nonreproductive tasks in two permanently and independently derived social spider species asking the following questions: Do individual spiders vary consistently in their propensity to engage in prey attack? Are individual spiders' propensities to engage in web maintenance behaviour influenced by their previous engagement in prey attack? Interestingly, we found that both species showed some degree of task specialization, but in distinctly different ways: Stegodyphus sarasinorum showed behavioural asymmetries at the individual level, that is, individual spiders that had attacked prey once were more likely to attack prey again, independent of their body size or hunger level. In contrast, Anelosimus eximius showed no individual specialization, but showed differentiation according to instar, where adult and subadult females were more likely to engage in prey attack than were juveniles. We found no evidence for division of labour between prey attack and web maintenance. Different solutions to achieve task differentiation in prey attack for the two species studied here suggest an adaptive value of task specialization in foraging for social spiders.

Gene expression signatures for colorectal cancer microsatellite status and HNPCC

The majority of microsatellite instable (MSI) colorectal cancers are sporadic, but a subset belongs to the syndrome hereditary nonpolyposis colorectal cancer (HNPCC). Microsatellite instability is caused by dysfunction of the mismatch repair (MMR) system that leads to a mutator phenotype, and MSI is correlated to prognosis and response to chemotherapy. Gene expression signatures as predictive markers are being developed for many cancers, and the identification of a signature for MMR deficiency would be of interest both clinically and biologically. To address this issue, we profiled the gene expression of 101 stage II and III colorectal cancers (34 MSI, 67 microsatellite stable (MSS)) using high-density oligonucleotide microarrays. From these data, we constructed a nine-gene signature capable of separating the mismatch repair proficient and deficient tumours. Subsequently, we demonstrated the robustness of the signature by transferring it to a real-time RT-PCR platform. Using this platform, the signature was validated on an independent test set consisting of 47 tumours (10 MSI, 37 MSS), of which 45 were correctly classified. In a second step, we constructed a signature capable of separating MMR-deficient tumours into sporadic MSI and HNPCC cases, and validated this by a mathematical cross-validation approach. The demonstration that this two-step classification approach can identify MSI as well as HNPCC cases merits further gene expression studies to identify prognostic signatures.

Understanding movement control in infants through the analysis of limb intersegmental dynamics

One important component in the understanding of the control of limb movements is the way in which the central nervous system accounts for joint forces and torques that may be generated not only by muscle actions but by gravity and by passive reactions related to the movements of limb segments. In this study, we asked how the neuromotor system of young infants controls a range of active and passive forces to produce a stereotypic, nonintentional movement. We specifically analyzed limb intersegmental dynamics in spontaneous, cyclic leg movements (kicking) of varying intensity in supine 3-month-old human infants. Using inverse dynamics, we calculated the contributions of active (muscular) and passive (motion-dependent and gravitational) torque components at the hip, knee, and ankle joints from three-dimensional limb kinematics. To calculate joint torques, accurate estimates were needed of the limb's anthropometric parameters, which we determined using a model of the human body. Our analysis of limb intersegmental dynamics explicitly quantified the complex interplay of active and passive forces producing the simple, involuntary kicking movements commonly seen in 3-month-old infants. our results revealed that in nonvigorous kicks, hip joint reversal was the result of an extensor torque due to gravity, opposed by the combined flexor effect of the muscle torque and the total motion-dependent torque. The total motion-dependent torque increased as a hip flexor torque in more vigorous kicks; an extensor muscle torque was necessary to counteract the flexor influences of the total motion-dependent torque and, in the case of large ranges of motion, a flexor gravity torque as well. Thus, with changing passive torque influences due to motions of the linked segments, the muscle torques were adjusted to produce a net torque to reverse the kicking motion. As a consequence, despite considerable heterogeneity in the intensity, range of motion, coordination, and movement context of each kick, smooth trajectories resulted from the muscle torque, counteracting and complementing not only gravity but also the motion-dependent torques generated by movement of the linked segments.

Idiopathic priapism in a young boy

We report a case of recurrent priapism in a boy. There were no recurrences during or after oral treatment with Bricanyl (terbutaline).

PIP2 binding residues of Kir2.1 are common targets of mutations causing Andersen syndrome

BACKGROUND

Mutations in KCNJ2, the gene encoding the inward-rectifying K+ channel Kir2.1, cause the cardiac, skeletal muscle, and developmental phenotypes of Andersen-Tawil syndrome (ATS; also known as Andersen syndrome). Although pathogenic mechanisms have been proposed for select mutations, a common mechanism has not been identified.

METHODS

Seventeen probands presenting with symptoms characteristic of ATS were evaluated clinically and screened for mutations in KCNJ2. The results of mutation analysis were combined with those from previously studied subjects to assess the frequency with which KCNJ2 mutations cause ATS.

RESULTS

Mutations in KCNJ2 were discovered in nine probands. These included six novel mutations (D71N, T75R, G146D, R189I, G300D, and R312C) as well as previously reported mutations R67W and R218W. Six probands possessed mutations of residues implicated in binding membrane-associated phosphatidylinositol 4,5-bisphosphate (PIP2). In total, mutations in PIP(2)-related residues accounted for disease in 18 of 29 (62%) reported KCNJ2 -based probands with ATS. Also reported is that mutation R67W causes the full clinical triad in two unrelated males.

CONCLUSIONS

The novel mutations corresponding to residues involved in Kir2.1 channel-PIP2 interactions presented here as well as the overall frequency of mutations occurring in these residues indicate that defects in PIP2 binding constitute a major pathogenic mechanism of ATS. Furthermore, screening KCNJ2 in patients with the complex phenotypes of ATS was found to be invaluable in establishing or confirming a disease diagnosis as mutations in this gene can be identified in the majority of patients.

Submillimeter-wave phonon modes in DNA macromolecules

A detailed investigation of phonon modes in DNA macromolecules is presented. This work presents experimental evidence to confirm the presence of multiple dielectric resonances in the submillimeter-wave spectra (i.e., approximately 0.01-10 THz) obtained from DNA samples. These long-wave (i.e., approximately 1-30 cm(-1)) absorption features are shown to be intrinsic properties of the particular DNA sequence under study. Most importantly, a direct comparison of spectra between different DNA samples reveals a large number of modes and a reasonable level of sequence-specific uniqueness. This work establishes the initial foundation for the future use of submillimeter-wave spectroscopy in the identification and characterization of DNA macromolecules.

The translating platform paradigm: perturbation displacement waveform alters the postural response

The translating platform paradigm is widely used to investigate the regulation of upright standing and locomotion. This study investigated how the displacement waveform characteristics underlying the translating platform perturbation are revealed in the resulting postural response. Eight participants experienced a series of backward-directed perturbations using a hydraulically driven forceplate. Two ranges of platform displacement (5 and 15 cm) in combination with two peak velocities (40 and 60 cm/s) were achieved using three distinct waveforms for platform displacement: (a) RAMP: ramp onset and ramp offset, (b) Ramp-to-Parabola (R-P): ramp onset with parabolic offset and (c) SINE: sine-wave onset with sine wave offset. Our findings indicated that the unique and distinctive acceleration and deceleration characteristics that result from the three different platform displacement waveforms significantly altered the postural response to the perturbation.

Compensatory stepping: the biomechanics of a preferred response among older adults

The purpose of this study was to evaluate age-related differences in the mechanics of the compensatory stepping response to balance threats. A moving platform was used to disturb the balance of 16 younger (21 to 35 years) and 19 older (68 to 88 years) adults. Backward platform translations consisted of 15-cm displacements with peak accelerations ranging from 9.4 to 15.2 m/s2. Older adults were more likely to use a step to recover balance and stepped at lower perturbation magnitudes than younger adults. Group differences were not found in time to step initiation or segmental momentum. The lack of group differences in momentum revealed that lower perturbation accelerations created an equivalent or greater magnitude of body motion in older adults compared to higher accelerations experienced by younger adults. Older adults also showed a reduced ability to attenuate the input acceleration and experienced significantly greater linear acceleration of the head.

Randomized trial of topically applied repifermin (recombinant human keratinocyte growth factor-2) to accelerate wound healing in venous ulcers

About 600,000 people in the United States are estimated to be affected by venous ulcers. The cornerstone of care of chronic venous ulcers involves the application of compression bandages. Other therapies include treatment of associated infection, treatment for edema and inflammation, and debridement when necessary. Repifermin, a recombinant human KGF-2 (fibroblast growth factor-10), exerts a proliferative effect on epithelial cells, in vitro and in vivo, and has been shown to accelerate wound healing in several experimental animal models. A randomized, double-blind, parallel-group, placebo-controlled, multicenter study was conducted to evaluate the safety and efficacy of topical repifermin treatment, for 12 weeks, in the healing of chronic venous ulcers in 94 patients. Repifermin was shown to accelerate wound healing, with significantly more patients achieving 75% wound closure with repifermin than with placebo. The treatment effect appeared more marked for a subgroup of patients with initial wound areas < or = 15 cm2 and wound ages of < or = 18 months. A longer duration of treatment (e.g., 26 weeks) may allow better differentiation of the benefit of repifermin compared with placebo, particularly with respect to complete wound closure. The safety assessment showed that repifermin was well tolerated.

Oligodontia is associated with extra-oral ectodermal symptoms and low whole salivary flow rates

INTRODUCTION

Ectodermal dysplasias (EDs) involve abnormal development of hair, teeth, nails, and sweat glands.

OBJECTIVES

(1) To investigate the frequency of extraoral ectodermal symptoms in persons with oligodontia (>6 congenitally missing teeth). (2) To examine whole salivary flow rates in oligodontia patients, with special emphasis on persons with EDs. SURVEY GROUP AND METHODS: Sixty-eight persons with oligodontia and 39 healthy control persons were included. All participants underwent an interview, general and oral examinations, and whole salivary secretory tests.

RESULTS

Thirty-nine (57%) of the oligodontia patients had disturbances in either hair, nails and/or sweat production in addition to teeth and were classified as the ED group. The remaining 29 oligodontia patients had no obvious signs of EDs (non-ED group). The prevalences of dry skin, asthma and eczema were higher, and whole salivary secretory rates lower, in the ED group as compared to the control group. Intermediate values were observed in the non-ED group. Incisors, canines and molars were more frequently missing in the ED group than in the non-ED group, whereas no differences were observed in the frequency of missing premolars. Negative correlations between the number of missing teeth and unstimulated and chewing stimulated whole salivary secretory rates were found.

Molecularly imprinted polymer sensors for pesticide and insecticide detection in water

Antibodies, peptides, and enzymes are often used as molecular recognition elements in chemical and biological sensors. However, their lack of stability and signal transduction mechanisms limits their use as sensing devices. Recent advances in the field of molecularly imprinted polymers (MIPs) have created synthetic materials that can mimic the function of biological receptors but with less stability constraints. These polymers can provide high sensitivity and selectivity while maintaining excellent thermal and mechanical stability. To further enhance the advantages of the traditional imprinted polymer approach, an additional fluorescent component has been introduced into these polymers. Such a component provides enhanced chemical affinity as well as a method for signal transduction. In this type of imprinted polymer, binding of the target analyte invokes a specific spectral signature from the reporter molecule. Previous work has provided molecularly imprinted polymers that are selective for the hydrolysis products of organophosphorus species such as the nerve agents sarin and soman. (A. L. Jenkins, O. M. Uy and G. M. Murray, Anal. Chem., 1999, 71, 373). In this paper the direct imprinting of non-hydrolyzed organophosphates including pesticides and insecticides is described. Detection limits for these newly developed MIP sensors are less than 10 parts per trillion (ppt) with long linear dynamic ranges (ppt to ppm) and response times of less than 15 min.

Development of lower extremity kinetics for balance control in infants and young children

Developmental changes in the kinematics and kinetics underlying balance control were studied in 61 children, 9 months to 10 years of age. The children were classified according to developmental milestones as standers; new, intermediate, and advanced walkers; runners-jumpers; hoppers; gallopers; and skippers. The children experienced support-surface translations of varying size and speed. Children with greater locomotor experience withstood larger balance threats without collapsing or stepping. Analyses of scaled trials (perturbations normalized in size to foot length and center of gravity height) revealed that improvement in balance was not related to initial configuration parameters surrounding the task (degree of crouch or lean). Children with advanced locomotor skills had faster recovery times and relatively larger muscle torques than children with less experience. Relative torque-time histories of the more experienced children began to match the adult response to similar perturbations. With increased experience and changing muscle torque regulatory abilities, balance skills became more robust.

Basal cell carcinoma of the buccal mucosa

True basal cell carcinoma (BCC) involving the oral mucous membranes is extraordinarily rare. Most of those described as occurring in the oral cavity usually involve the gingiva and are not true BCCs but peripheral ameloblastomas. A true BCC, which arose on the buccal mucosa of a 69-year old man, is reported. It presented as a 1.3 cm ulcerated plaque without gingival connection. Histologically, the lesion exhibited classic features of BCC with palisading and retraction spaces, and focally communicated with the overlying squamous epithelium. Although it is possible that this lesion also arose from a heterotopic odontogenic rest, the anatomical location, focal squamous (metatypical) features, and positive staining for Ber-EP4 support an origin from the basal cell layer of stratified squamous mucosa.

Intralimb coordination following obstacle clearance during running: the effect of obstacle height

The purpose of this study was to investigate the different coordination strategies used following obstacle clearance during running. Ten subjects ran over a level surface and over obstacles of six different heights (10, 12.5, 15, 17.5, 20 and 22.5% of their standing height). Analysis based upon the dynamical systems theory (DST) was used and the phasing relationships between lower extremity segments were examined. The results demonstrated that the increasing obstacle height elicited behavioral changes. The foot and the leg became more independent in their actions, while the leg and the thigh strengthened their already stable relationship. The 15% obstacle height seems to be a critical height for the observed changes.

A dependent-rates model and an MCMC-based methodology for the maximum-likelihood analysis of sequences with overlapping reading frames

We present a model and methodology for the maximum-likelihood analysis of pairwise alignments of DNA sequences in which two genes are encoded in overlapping reading frames. In the model for the substitution process, the instantaneous rates of substitution are allowed to depend on the nucleotides occupying the sites in a neighborhood of the site subject to substitution at the instant of the substitution. By defining the neighborhood of a site to extend over all sites in the codons in both reading frames to which a site belongs, constraints imposed by the genetic code in both reading frames can be taken into account. Due to the dependency of the instantaneous rates of substitution on the states at neighboring sites, the transition probability between sequences does not factorize and therefore cannot be obtained directly. We present a Markov chain Monte Carlo procedure for obtaining the ratio of two transition probabilities between two sequences under the model considered, and we describe how maximum-likelihood parameter estimation and likelihood ratio tests can be performed using the procedure. We describe how the expected numbers of different types of substitutions in the shared history of two sequences can be calculated, and we use the described model and methodology in an analysis of a pairwise alignment of two hepatitis B sequences in which two genes are encoded in overlapping frames. Finally, we present an extended model, together with a simpler approximate estimation procedure, and use this to test the adequacy of the former model.

A dynamical systems investigation of lower extremity coordination during running over obstacles

OBJECTIVE

To investigate intralimb coordination during running over a level surface and over obstacles of three different heights.

DESIGN

The phasing relationships between the foot and leg motions in the frontal plane, and the shank and thigh motions in the sagittal plane were used to compare patterns of coordination.

BACKGROUND

The coordinated actions of lower extremity segments are necessary to absorb the impact forces generated during running. The behavioral patterns of these segments can be studied under changing task demands using analysis techniques from the Dynamical Systems Theory.

METHODS

Ten subjects ran at their self-selected pace under four conditions: over a level surface and over obstacles of different heights (5%, 10%, 15% of their standing height). A force platform was used to record impact forces during landing after obstacle clearance, while kinematics were collected using a two-camera system.

RESULTS

The increases in obstacle height resulted in significant changes in impact forces (34% increase between the two extreme conditions) and more in-phase relationships between the segments during early stance. No changes were observed in the variability of the phasing relationships.

CONCLUSIONS

The coordination changes observed might be compensatory strategies aimed to reduce forces and potential injury. However, since the impact forces still increased significantly, it is also possible that the observed changes might be at-risk movement patterns predisposing runners to injury.

How do non-muscular torques contribute to the kinetics of postural recovery following a support surface translation?

The common platform translation paradigm used in balance control studies employs a disturbance event that applies non-muscular forces to the body for the duration of the disturbance. Previous research has explored the process of constructing the balance recovery by considering these perturbations to be trigger events, not events with an ongoing force application timeline. The purpose of this study was to quantify the effect of muscular and non-muscular torques on post-perturbation balance with particular interest in the role of the external perturbation in balance recovery. Five young adult males experienced backward translations of the support surface at three different speeds. Integration intervals were defined for each segment and angular impulses were calculated for a period of increasing angular momentum (destabilization), and a period of decreasing angular momentum (restabilization). Destabilization of distal segments was primarily due to impulse generated by the motion of the support surface. For the trunk, however, muscle and motion-dependent sources contributed most to increasing momentum. Restabilization of distal segments was achieved by muscle and platform impulses while trunk restabilization was achieved by muscle and motion-dependent terms in opposition to gravity. Increased platform speed resulted in increased muscular contribution only in the control of the trunk, while demand on distal musculature decreased with change in platform speed as the platform contribution to restabilization increased in these segments. Therefore, impulses from non-muscular sources, including the perturbation itself, are significant modifiers of the response to balance disturbances and must be accounted for in balance research.

Partial paternal uniparental disomy of chromosome 6 in an infant with neonatal diabetes, macroglossia, and craniofacial abnormalities

Neonatal diabetes, which can be transient or permanent, is defined as hyperglycemia that presents within the first month of life and requires insulin therapy. Transient neonatal diabetes mellitus has been associated with abnormalities of the paternally inherited copy of chromosome 6, including duplications of a portion of the long arm of chromosome 6 and uniparental disomy, implicating overexpression of an imprinted gene in this disorder. To date, all patients with transient neonatal diabetes mellitus and uniparental disomy have had complete paternal isodisomy. We describe a patient with neonatal diabetes, macroglossia, and craniofacial abnormalities, with partial paternal uniparental disomy of chromosome 6 involving the distal portion of 6q, from 6q24-qter. This observation demonstrates that mitotic recombination of chromosome 6 can also give rise to uniparental disomy and neonatal diabetes, a situation similar to that observed in Beckwith-Wiedemann syndrome, another imprinted disorder. This finding has clinical implications, since somatic mosaicism for uniparental disomy of chromosome 6 should also be considered in patients with transient neonatal diabetes mellitus.

Spatial mixture modeling of fMRI data

Recently, Everitt and Bullmore [1999] proposed a mixture model for a test statistic for activation in fMRI data. The distribution of the statistic was divided into two components; one for nonactivated voxels and one for activated voxels. In this framework one can calculate a posterior probability for a voxel being activated, which provides a more natural basis for thresholding the statistic image, than that based on P-values. In this article, we extend the method of Everitt and Bullmore to account for spatial coherency of activated regions. We achieve this by formulating a model for the activation in a small region of voxels and using this spatial structure when calculating the posterior probability of a voxel being activated. We have investigated several choices of spatial models but find that they all work equally well for brain imaging data. We applied the model to synthetic data from statistical image analysis, a synthetic fMRI data set and to visual stimulation data. Our conclusion is that the method improves the estimation of the activation pattern significantly, compared to the nonspatial model and to smoothing the data with a kernel of FWHM 3 voxels. The difference between FWHM 2 smoothing and our method were more modest.

Metal-catalyzed oxidation of brain-derived neurotrophic factor (BDNF): selectivity and conformational consequences of histidine modification

We have studied the metal-catalyzed oxidation (MCO) of brain-derived neurotrophic factor (BDNF) with regard to target sites and potential conformational changes of the protein. The exposure of BDNF to three different levels of ascorbate/Cu(II)/O2 [20 microM Cu(II), 2 mM ascorbate (level 1); 20 microM Cu(II), 4 mM ascorbate (level 2); 40 microM Cu(II), 4 mM ascorbate (level 3)], chosen based on the extent of chemical modification of Met and His, respectively, resulted in the exclusive oxidation of a buried Met residue, Met92, at level 1 but in the predominant oxidation of His at level 3. His modification had a significant impact on the structure of BDNF, as quantified by CD and ANSA fluorescence measurements, while Met oxidation had not, also assessed through complementary oxidation of BDNF through hydrogen peroxide. Our ultimate objective was the correlation of the surface exposure of an oxidized His residue in a protein with potential effects on the conformational integrity of the oxidized protein. In a series of three proteins, human growth hormone (hGH), human relaxin (hR1x), and BDNF, we have now observed that His oxidation is paralleled by significant conformational changes when the target His residue is more surface exposed (hR1x, BDNF) while conformational consequences of His modification are less significant when the target His residues are more buried in the interior of the protein (hGH).

The development of compensatory stepping skills in children

The development of the ability to use the step for balance recovery was studied among twenty-five 9- to 19-month-old children. The children were grouped according to walking experience (4 levels) and exposed to backward support surface translations, 8 cm in amplitude, under 3 velocity conditions: 15, 20, and 25 cm/s. New walkers (up to 2 weeks' walking experience) used the step infrequently and ineffectively in response to threats to balance. Intermediate walkers (1-3 months' walking experience) showed an increasing use of the step and significant improvement in step execution compared with new walkers. Advanced walkers (>3; months' walking experience) experienced no falls throughout the protocol, capturing balance with feet-in-place or step responses under all perturbation conditions. A significant developmental transition in the emergence of the compensatory step occurred between the new walker and the intermediate walker experience levels, that is, within the first 3 months of walking experience. Three to 6 months' experience was required for the development of an effective stepping response. A concomitant change in mediolateral stability paralleled the emergence of compensatory stepping.

Metal-catalyzed oxidation of brain-derived neurotrophic factor (BDNF): analytical challenges for the identification of modified sites

PURPOSE

We examined the metal-catalyzed oxidation of brain-derived neurotrophic factor (BDNF) using the Cu(II)/ascorbate/O2 model oxidative system.

METHODS

Electrospray ionization mass spectrometry, peptide mapping and amino acid analysis were utilized to determine the nature of the covalent modification induced by the metal-catalyzed oxidative system. Additionally, analytical ultracentrifugation, the Bradford assay, circular dichroism and ANSA dye-binding were used to determine the nature of any conformational changes induced by the oxidation.

RESULTS

Exposure of BDNF to the Cu(II)/ascorbate/O2 system led to the modification of ca. 35% of Met92 to its sulfoxide, and to subsequent conformational changes. The proteolytic digestion procedure was sensitive to this conformational change, and was unable to detect the modification. Chemical digestion with CNBr, however, was not sensitive to this change, and allowed for the identification of the site of modification.

CONCLUSIONS

The modification of Met92 to its sulfoxide rendered the oxidized BDNF inaccessible to proteolytic digestion, due to conformational changes associated with the oxidation.

A procedure to determine equilibrium postural configurations for arbitrary locations of the feet

This research was directed toward predicting postural equilibrium configurations in normal humans for asymmetric locations of the feet. The objective of the study was to identify trends in the variation of the location of ground center of pressure (COP) with increasing levels of asymmetry in the foot placement. The procedure developed here minimized the muscular effort (active torques) in the lower extremities while maximizing postural stability margins for given foot locations. Minimizing muscular effort led to fully extended knees, and maximal stability margin led to the COP moving toward the rear foot in asymmetric stance. A combined analytical-numerical optimization scheme was used to avoid singularities that can arise due to the fact that at equilibrium postural configurations, the torso lies at or near the workspace boundary of the lower extremities. Experiments were conducted and the results obtained were in keeping with the model predictions. This basic understanding of asymmetric stance is important for studying asymmetric postural mechanics in the presence of external disturbances, and for extending the results from normal subjects to humans at both ends of the life span.

Age-related changes in rate and magnitude of ankle torque development: implications for balance control

BACKGROUND

One of the key components of postural control is the motor system's ability to produce appropriate torques to counteract perturbations that may lead to a loss of balance. Evidence exists to show that there is an age-related decline in absolute strength and in the ability to rapidly produce torque. The relationship between age-related decreases in these voluntary torque production capabilities and the ability to rapidly produce torques in a reactive balance task has not been studied. Thus, the purpose of this study was to examine the magnitude and rate of torque production in younger and older adults under reactive balance conditions.

METHODS

Older (OA) and younger (YA) adults received forward and backward support surface translations of varying amplitudes and velocities. Maximum ankle muscle torque (maxMa) and rate of change of ankle muscle torque (Ma) following a perturbation were calculated.

RESULTS

Two balance responses emerged: a no-step and a step response. With increasing perturbation difficulty, YA and OA used different responses. The no-step and step responses were examined for age-group differences in the force characteristics. No significant age-group differences were found for maxMa or rate of change of Ma within either no-step or step responses.

CONCLUSION

The results of this study suggest that neither the magnitude nor rate of ankle muscle torque production, as produced during the initial balance response in this set of reactive balance control tasks, determines the different balance responses seen in younger versus older adults.

Oral and ocular sicca symptoms and findings are prevalent in systemic lupus erythematosus

The aims of this study were 1) to examine the frequency of oral and ocular sicca symptoms in patients with systemic lupus erythematosus (SLE); 2) to compare saliva and tear volume, salivary proteins, and features of the oral microflora and mucosa to a matched healthy control group; and 3) to relate the findings to disease parameters. Median disease duration was 5.5 (0.5-28) years, disease activity 5 (2-20), damage score 1 (0-7), and Schirmer I test 7.5 (0-30 mm). Seventeen and twelve patients complained of oral and ocular dryness, respectively. Unstimulated whole saliva and proline-rich proteins in submandibular saliva were significantly reduced in SLE. Oral microbial counts were generally higher in the patients than controls, and the number of oral mucosal changes was increased. The results show that sicca symptoms, although frequent, were not correlated to secretory rates of saliva or tears, but to oral microbial counts. There was no obvious correlation to patient's age, disease activity or duration.

Sicca symptoms, saliva and tear production, and disease variables in 636 patients with rheumatoid arthritis

OBJECTIVES

(1) To estimate the prevalence of ocular and oral sicca symptoms (SISY) or reduced saliva and tear production; (2) to relate SISY and sicca signs to measures of disease activity, damage, and health status; and (3) to examine the relation between symptoms and objective signs of tear and saliva production in a large sample of representative patients with rheumatoid arthritis (RA).

METHODS

From an unselective county RA register 636 patients (age 20-70 years) were examined with Schirmer-I test (ST), unstimulated whole saliva (UWS), questions on SISY and measures of disease activity, damage and health status.

RESULTS

Ocular sicca symptoms were reported in 38%, oral sicca symptoms in 50%, and a combination of both in 27%. Reduced tear production was present in 29%, and reduced saliva production in 17%. The minimum frequency of secondary Sjögren's syndrome was 7%. Measurements of exocrine disease manifestations were to variable extents bivariately correlated to disease activity measures, physical disability, pain, fatigue, and use of xerogenic drugs, but were not related to deformed joint count. Multivariate analyses revealed significant associations between disease activity and reduced saliva production. Only weak associations between SISY and tear or saliva production were observed.

CONCLUSION

SISY, reduced tear and saliva production were frequent extra-articular manifestations in RA, but were only weakly intercorrelated. High disease activity and at least two SISY were independent predictors of reduced saliva production, but ocular and oral dryness did not seem to be closely related to disease duration, disease activity, damage or health status.

A randomized clinical study comparing a hydrocellular dressing to a hydrocolloid dressing in the management of pressure ulcers

This study compared an adhesive hydrocellular dressing with a leading hydrocolloid dressing in the management of pressure ulcers. Forty adult patients of both sexes who had Stage II or III pressure ulcers (according to the Agency for Health Care Policy and Research system) were enrolled in the study and were randomized to either the hydrocellular or hydrocolloid dressing. Dressing changes were done as required, and each ulcer was assessed on a weekly basis. Patients were followed for 8 weeks, until ulcer closure was achieved, or until the patient was withdrawn from the study, whichever occurred first. The hydrocellular dressing was found to compare favorably with the hydrocolloid dressing. In terms of ease of use, the hydrocellular dressing was found to be significantly easier to remove (P < 0.001) and quicker to change (P < 0.001) than the hydrocolloid dressing. No differences were detected between the two dressing groups regarding mean wound pain, odor, and changes in ulcer appearance and ulcer area.

Outpatient 5-fluorouracil, folinic acid and cisplatin in patients with advanced esophageal carcinoma

In a multicenter phase II study, 30 patients with unresectable, locally advanced or metastatic squamous cell or adenocarcinoma of the esophagus were treated with folinic acid 200 mg/m2/d, 5-FU 300 mg/m2/d, and cisplatin 20 mg/m2/d intravenously for 5 days every 4 weeks. Two of 13 patients with squamous cell carcinoma (SCC) had a complete response (CR), but one died of pneumonia after 9 months while still in CR, and the other still in CR after more than 5 years. Six other patients (3 SCC, 2 of 16 with adenocarcinoma, 1 mixed histology) had a partial response with a median duration of 9 months (range 5 to 57 + months) for an overall response rate of 27%. A further 6 patients (20%) had stable disease. Grade 4 neutropenia occurred in 6 patients (20%), with 5 requiring antibiotics for associated fever. Other grade 4 toxicities were nausea and vomiting (1), anemia (1), and thrombocytopenia (1); there were three early deaths (emphysema, cardiac arrest, pulmonary embolism). This combination appears to be an active, convenient regimen for advanced esophageal cancer, resulting in prolonged remission and survival in some patients.

Primary Sjögren's syndrome: salivary gland function and clinical oral findings

OBJECTIVE

To evaluate salivary gland function, saliva composition and oral findings in patients with primary Sjögren's syndrome (pSS) subdivided into patients with and without focus score > or = 1 (FS) and/or antibodies to SSA/SSB (AB) as well as in healthy controls.

SUBJECTS AND METHODS

Unstimulated (UWS) and chewing stimulated (SWS) whole saliva, and stimulated parotid saliva (SPS) were collected in 16 patients fulfilling the European classification criteria for pSS subdivided into those with FS and/or AB (n = 8) and those without FS and AB (n = 8), and in age-matched (n = 14) and young healthy controls (n = 13). UWS and SWS were analysed for Na+ and K+. SPS was analysed for Na+, K+, statherin, and proline-rich proteins (PRPs). Sicca symptoms, DMFT/DMFS, plaque (PI) and gingival (GI) scores, periodontal pocket depth (PPD), and mucosal status were recorded.

RESULTS

The young healthy controls had lower UWS as compared to the aged controls (P = 0.03). However, the aged controls had higher DMFT/DMFS (P < 0.001) and PI, GI and PPD (P < 0.01). Patients with FS and/or AB generally had lower saliva secretory rates than patients without FS and/or AB (P = 0.01 for UWS and SPS) and age-matched healthy controls (P = 0.001). There was no significant difference in the content of Na+ and K+, statherin and PRPs between groups. Patients with FS and/or AB had the highest frequency of oral mucosal changes and higher DMFT/DMFS than patients without FS and/or AB and healthy controls (P < 0.01). However, PI, GI, and PPD did not differ significantly.

CONCLUSION

Patients with FS and/or AB had lower salivary secretory rates, higher DMFT/DMFS, and more oral mucosal changes than patients without FS and/or AB. Additionally, data suggest that salivary gland function in healthy individuals do not decrease with age.

Salivary secretions: narcolepsy and central nervous system stimulants

In an ongoing attempt to develop a model to study the influence of various diseases and drugs on saliva, we studied persons with narcolepsy treated with central nervous system stimulants. The aim was to study the secretion of salivary proteins in narcolepsy in the presence and absence of central nervous system stimulants. For this purpose, two proteins synthesized in acinar cells, acidic proline-rich proteins (PRPs) and statherin, were selected. Persons with narcolepsy treated with central nervous system stimulants only were included, n = 12, ages 14 to 68, seven females. Citric-acid-stimulated parotid and submandibular/sublingual saliva samples were collected from these persons during medication, after a drug-free period of one week, at least two weeks after the drug had been re-introduced, and from a matched healthy control group. PRP and statherin concentrations were determined by means of reversed-phase and anion exchange chromatography, respectively. Both concentration and output of statherins and PRPs were increased in persons with narcolepsy receiving central nervous system stimulants compared with healthy control individuals. When the drug was withdrawn, salivary flow rates were not influenced. In contrast, withdrawal of the drug led to a significantly decreased secretion of PRPs and statherin. The reduced protein secretion may reflect decreased adrenergic activation in narcolepsy, to be reversed by treatment with central nervous system stimulants. It can be concluded that measurements of both salivary fluid and salivary proteins may be necessary for an overall evaluation of the effects of a given drug or disease on salivary secretion.

Salivary secretion: stimulatory effects of chewing-gum versus paraffin tablets

Paraffin tablets are commonly used in clinical saliva tests whereas chewing-gum is recommended to increase salivation in xerostomic patients. The aim of this study was to compare the effect on salivation of these stimuli. Saliva stimulated by chewing-gum or paraffin tablets was sampled on separate occasions from eight healthy subjects (25-45 yr). Whole or parotid saliva were collected for 6 min (1 min + 5 min) and 21 min (1 min + 5 min x 4), respectively. pH of saliva was measured with and without the addition of HC1 (titrated pH). Total parotid protein was measured using the microBSA-assay. Initially, flow rates were significantly higher during the chewing of gum vs. paraffin tablets (whole saliva 5.18 vs. 2.99 ml/min, parotid saliva 0.83 vs. 0.42 ml/min). Conversely, during final chewing periods, parotid flow rates, pH, and titrated pH were significantly higher during paraffin chewing. When comparing the stimuli, parotid protein output was higher initially during gum chewing, but in the final period paraffin chewing elicited the higher output. It was concluded that the clinical test of paraffin chewing gives a good estimate of the expected whole saliva response to chewing-gum. Furthermore, extended chewing of paraffin tablets seemed to influence parameters of parotid saliva positively.

Salivary gland involvement in hypohidrotic ectodermal dysplasia

Ectodermal dysplasias (EDs) are a group of developmental disorders (more than 100) mainly affecting ectodermal tissues and organs. The X-linked hypohidrotic ED (HED) is the most common form of EDs, involving defects in teeth, sweat glands, and hair. In a few reports, HED has been associated with reduced salivary function. In the present case report, a dramatically reduced salivary fluid and acidic proline rich protein production was identified in a 38-year-old man with HED. Computed tomography was performed, revealing that one submandibular gland and both parotid glands were hypoplastic, whereas the right submandibular gland seemed to be absent. These findings are in line with a general developmental disturbance also involving the salivary glands. As salivary tests are inexpensive and easy to perform, it is suggested to routinely evaluate salivary secretion in persons with HED, to prevent a possible negative impact on oral health.

Clinical implications of the dry mouth. Oral mucosal diseases

Salivary hypofunction caused by salivary gland disease, medication, or radiation may predispose for secondary oral mucosal diseases. In these patients the protective coating of saliva is reduced or absent, leaving the oral mucosa more vulnerable. Candidiasis, burning mouth syndrome, and white lesions of the oral mucosa are increased in frequency. The aim of management is to prevent oral pathological changes. The management procedure may include proper oral hygiene, saliva-stimulating agents, or saliva substitutes, depending on the severity of the salivary dysfunction. Treatment includes antifungal therapy if candidiasis is diagnosed. In severely distressed patients, local or systemic corticosteroids may be indicated. Precautions, like refraining from smoking and avoiding toothpastes containing sodium lauryl sulfate, should also be taken. In the future, agents combining antibacterial and antiinflammatory actions, like triclosan, may show promising effects in patients with oral mucosal diseases secondary to salivary hypofunction.

Salivary acidic proline-rich proteins in rheumatoid arthritis

In an ongoing attempt to investigate qualitative salivary parameters in diseases affecting salivary glands, patients with rheumatoid arthritis (RA) were examined. Patients were selected from the Oslo RA register for the present study if they fulfilled the following criteria: age 52-74 years, disease duration 10-20 years, and disability score as assessed by the Modified Health Assessment Questionnaire < or = 2.5. From these 105 patients, two subgroups of patients were selected, one group with pronounced sicca symptoms from eyes and mouth, and one group without such symptoms. Sicca symptoms were assessed using a postal questionnaire with the questions on dry mouth and dry eyes of the European classification criteria for Sjögren's syndrome. Patients were excluded from further examinations if they used medication that could cause dryness in eyes or mouth. Thus, nine patients remained in the sicca group (having four or more sicca symptoms), and ten matched RA patients were selected for the nonsicca group. A healthy sex- and age-matched control group (n = 10) was also examined. In a preliminary report we have shown that differences in flow rates between sicca and nonsicca RA patients were limited to lower values of unstimulated whole saliva. To further evaluate salivary changes in RA, a disease frequently associated with secondary Sjögren's syndrome, we have studied qualitative salivary parameters in these patients,' including secretory rates of proline-rich proteins (PRPs), statherins, and histatins. In the present report, phenotypes of PRPs, the ratio of PRPs derived from the two loci (PRH1 and PRH2), and PRP concentration and output in parotid and submandibular saliva derived from the two loci are presented. Parotid (PS) and submandibular saliva (SS) were collected from all individuals using 2% citric acid as a saliva stimulus. PRPs in PS and SS were identified using a SMART microchromatographic system with a Mono Q column and a Tris-HCl/NaCl gradient (method adapted from ref. 5). For PRPs, the primary polypeptide products are coded for on two loci (PRH1 and PRH2), which have three and two commonly occurring gene variants, respectively. On PRH1, the proteins PIF-s, Db-s, and Pa are coded for, whereas PRP-1 and PRP-2 are coded for on the PRH2 locus. As each protein variant has a postranscriptional cleavage product, individuals will exhibit four, six, or eight PRPs in their saliva, depending on whether they are homozygous at both, one, or neither of the two loci. Accordingly, 18 possible phenotypes may exist, but as few as three phenotypes were found in 79% of the 127 healthy individuals examined by Hay et al. The SMART system allows the determination of the different acidic PRPs present in saliva. Concentrations of the various phenotypes were calculated by peak integration versus pure PRP standards. Total PRP concentration derived from each locus was calculated as the sum of the concentrations of PRP variants from that locus.

The DnaJ family of protein chaperones in Trypanosoma cruzi

We have molecularly cloned four members of the DnaJ (heat shock protein 40) family of protein chaperones of the protozoan parasite Trypanosoma cruzi--tcj1, tcj2, tcj3 and tcj4. While all the proteins contain defining J domains at their N-termini, only tcj2, tcj3 and tcj4 contain glycine/phenylalanine-rich and zinc finger domains common to many other DnaJ homologues. Furthermore, tcj2 and tcj4 contain C-terminal CaaX motifs, substrates for prenyl modifications, suggesting that they are associated with cellular membranes. tcj1 is a divergent member of the family, containing neither glycine/phenylalanine-rich nor zinc finger domains. All the T. cruzi DnaJ genes are single copy, in contrast to other T. cruzi heat shock genes, which are arranged in multicopy direct tandem arrays. Among the tcj mRNAs, only tcj2 is heat inducible, which may result from posttranscriptional regulation involving a sequence found in the 3' untranslated regions of all heat-inducible T. cruzi mRNAs described to date. Further study of this important family of protein chaperones will aid our understanding of the protein folding and assembly processes in protozoans.

Characteristics of rheumatoid arthritis patients with self-reported sicca symptoms: evaluation of medical, salivary and oral parameters

OBJECTIVES

To examine the prevalence of sicca symptoms in rheumatoid arthritis (RA)-patients, and to evaluate medical, salivary, and oral parameters in matched subgroups of patients with and without sicca symptoms as well as in healthy controls.

PATIENTS AND METHODS

The prevalence of self-reported sicca symptoms was examined by a postal questionnaire in a representative cohort of RA-patients (n = 105, aged 52-74 years, disease duration 10-20 years, 77% females, 56% RF-positive). Patient subgroups and controls (9-10 in each group) underwent examinations of disease activity, blood analyses, tests of tear and salivary secretion, and examination of oral mucosa and microflora. Analyses of salivary acidic proline-rich proteins (PRPs), statherin and histatins were performed.

RESULTS

One or more sicca symptoms were reported by 65% of RA-patients. Sicca patients (having > or = 4 sicca symptoms) had a more active and severe disease with higher scores for disability, fatigue and tender joints than patients without such symptoms. Other significant findings in the sicca group were lower values of unstimulated whole saliva, output of PRPs, statherin and histatins in submandibular saliva, and higher counts of oral Candida species.

CONCLUSIONS

Sicca symptoms were prevalent in RA. Qualitative and quantitative salivary tests distinguished between sicca and non-sicca RA-patients, though overlap was considerable for some parameters.

[Temporary radiation-induced hypo-salivation in a child]

This case report deals with the diagnosis and treatment of hyposalivation after radical radiation therapy and cytotoxic treatment of a metastasising nasopharyngeal carcinoma in an eight-year old girl. After cancer treatment the patient suffered from xerostomia, and pronounced hyposalivation was demonstrated. Frequent chewing of sugar-free gum and use of lozenges was recommended, and the patient was followed up for one year. During this time, the values for unstimulated whole saliva increased by a factor of five, and stimulated whole saliva values increased as well, but less so. Two years after cancer treatment, the patient no longer suffers from xerostomia.

Millimeter wave-induced vibrational modes in DNA as a possible alternative to animal tests to probe for carcinogenic mutations

Developing methods for alternative testing is increasingly important due to dwindling funding resources and increasing costs associated with animal testing and legislation. We propose to test the feasibility of a new and novel method for detecting DNA mutagenesis using millimeter wave spectroscopy. Although millimeter wave spectroscopy has been known since the 1950s, the cost was prohibitive and studies did not extend to large biological proteins such as DNA. Recent advances have made this technology feasible for developing laboratory and field equipment. We present preliminary findings for lesion-induced vibrational modes in DNA observed from 80 to 1000 gigahertz (GHz). These findings suggest that there are vibrational modes that can be used as identification resonances. These modes are associated with localized defects of the DNA polymers. They are unique for each defect/lesion, and should be easy to detect. We described a field-detecting detector based on the local modes.