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1.
Sci Rep ; 13(1): 13340, 2023 08 16.
Article in English | MEDLINE | ID: mdl-37587172

ABSTRACT

Disturbances in the sleep-wake cycle are a debilitating, yet rather common condition not only in humans, but also in family dogs. While there is an emerging need for easy-to-use tools to document sleep alterations (in order to ultimately treat and/or prevent them), the veterinary tools which yield objective data (e.g. polysomnography, activity monitors) are both labor intensive and expensive. In this study, we developed a modified version of a previously used sleep questionnaire (SNoRE) and determined criterion validity in companion dogs against polysomnography and physical activity monitors (PAMs). Since a negative correlation between sleep time and cognitive performance in senior dogs has been demonstrated, we evaluated the correlation between the SNoRE scores and the Canine Dementia Scale (CADES, which includes a factor concerning sleep). There was a significant correlation between SNoRE 3.0 questionnaire scores and polysomnography data (latency to NREM sleep, ρ = 0.507, p < 0.001) as well as PAMs' data (activity between 1:00 and 3:00 AM, p < 0.05). There was a moderate positive correlation between the SNoRE 3.0 scores and the CADES scores (ρ = 0.625, p < 0.001). Additionally, the questionnaire structure was validated by a confirmatory factor analysis, and it also showed an adequate test-retest reliability. In conclusion the present paper describes a valid and reliable questionnaire tool, that can be used as a cost-effective way to monitor dog sleep in clinical settings.


Subject(s)
Juniperus , Sleep, Slow-Wave , Humans , Animals , Dogs , Pets , Reproducibility of Results , Sleep , Polysomnography , Snoring
2.
Hautarzt ; 73(1): 15-20, 2022 Jan.
Article in German | MEDLINE | ID: mdl-34846551

ABSTRACT

BACKGROUND: Studies show a spatial variation in skin cancer frequencies, but the causes have not been fully understood. When analysing spatial patterns and correlations, different approaches need to be considered, as the data have special features due to their spatial structure. AIM OF THE STUDY: Why the spatial consideration of skin cancer frequencies is important at all, and which methods of analysis are useful is considered in more detail in this article. The article provides an introduction and overview of statistical methods that are important for the spatial analysis of skin cancer frequencies. MATERIALS AND METHODS: At first it is shown which descriptive methods, such as statistical smoothing, can be applied. Next, spatial cluster and regression analyses will be discussed. Testing for spatial autocorrelation will be considered. RESULTS: In particular, the spatial dependence of the data on neighbouring regions, which if ignored can lead to biased estimates, is of particular importance in the analysis of spatial data and requires special spatial analysis methods. DISCUSSION: This article provides an introduction and overview of statistical methods relevant to the spatial analysis of skin cancers.


Subject(s)
Skin Neoplasms , Germany/epidemiology , Humans , Prevalence , Skin Neoplasms/epidemiology , Spatial Analysis
3.
Hautarzt ; 73(1): 40-46, 2022 Jan.
Article in German | MEDLINE | ID: mdl-34846553

ABSTRACT

The legal basis for describing the regional care situation is based on the adjusted supply rate of the 'demand planning guideline'. However, it provides only limited information about the accessibility of medical care which is crucial for the reality of patients' lives. The aim of this review is to present geographic approaches that spatially measure access to dermatological care in its physical and digital dimension. Here, on the one hand, the classical geographic parameter 'accessibility' is addressed, and on the other hand, data from the Federal Ministry of Transport and Digital Infrastructure (BMVI) on broadband coverage are presented as access parameters of teledermatological applications. In addition to the methodological approach, limitations and potentials in the interpretation of the results, minimum standards are also considered. The access parameters presented here make it possible to investigate spatial disparities and to present them clearly via cartographic representations. While the example of accessibility with a car shows almost area-wide access to the nearest dermatology practice (≤ 30 min), investigations on public transport accessibility reveal rather heterogeneous accessibility. Particularly in the identification of 'dual care gaps', sub-areas with poor physical and digital accessibility, these approaches could support and advance the application of alternative care models. However, the approaches presented here focus on potential accessibility. Further dimensions on actual physician utilisation or availability-also with regard to minimum standards-should be the subject of future research.


Subject(s)
Health Services Accessibility , Physicians , Humans
4.
Ophthalmologe ; 118(9): 933-939, 2021 Sep.
Article in German | MEDLINE | ID: mdl-33108498

ABSTRACT

BACKGROUND: Regional ophthalmologic care in Germany is ensured through the guidelines of the Federal Joint Committee's requirement planning and the adjusted supply rate defined therein. Although the adjusted supply rate is an official instrument for assessing the actual healthcare situation in Germany, earlier studies revealed limitations. Factors such as public transport accessibility or the existence of other healthcare professions are not considered to a sufficient extent, although they have a profound impact on the healthcare situation. The latter in particular have a strong supportive function in regional healthcare. OBJECTIVE: This study aimed to critically compare different parameters to evaluate the regional healthcare situation using the example of ophthalmologic care. MATERIAL AND METHODS: For this purpose a score was calculated for the districts of the Hamburg metropolitan region based on the exemplary parameters "density of ophthalmologists with orthoptic focus on a district level (offer/100,000 inhabitants)", "percentage of population with public transport accessibility to next ophthalmologist <30 min on a district level", "percentage of population with public transport accessibility to next ophthalmologist with orthoptic focus <30 min on a district level" and compared with the results of the adjusted supply rate. RESULTS: While the adjusted supply rate could not identify any case of undersupply in any of the districts, the other included parameters sometimes revealed clear differences in supply. CONCLUSION: The healthcare situation is heterogeneous by consideration of different parameters. This needs to be taken into account when assessing the regional healthcare situation for requirement planning.


Subject(s)
Delivery of Health Care , Health Services Accessibility , Germany , Humans
5.
J Eur Acad Dermatol Venereol ; 34(8): 1736-1743, 2020 Aug.
Article in English | MEDLINE | ID: mdl-31981431

ABSTRACT

BACKGROUND: Due to the increasing incidence of skin cancer, programmes for the prevention of skin cancer have been developed and implemented in Germany. However, utilization of skin cancer screenings shows marked regional differences. Reasons and predictors of such variations are unclear. OBJECTIVES: The objective of the study is to identify predictors for regional use of skin cancer screening variations in Germany. METHODS: Analysis of the population set of ambulatory claims data (2009-2015) of the statutory health insurances (SHI) in Germany (70.2 million people in 2015). Skin cancer screening utilization rate was determined on county level. Descriptive, cluster and multivariate analyses were performed to identify spatial patterns in skin cancer screening utilization. RESULTS: Overall, 6.5-7.9 million people participated in skin cancer screenings. Utilization rates of people ≥35 years of age were 9.74% (2009) and 10.96% (2015). Marked regional variations were identified between the counties. Dermatologists in Saxony and Westphalia-Lippe as well as general practitioners in Lower Saxony and North Rhine showed particularly high utilization rates. Multiple regression analyses demonstrated e.g. positive associations between the skin cancer screening utilization rates and employees with higher vocational qualifications and shorter travel time by car to the nearest major urban centre. CONCLUSION: Utilization rates of skin cancer screening vary largely in Germany with specific spatial patterns. Multivariate analyses demonstrate associations with socio-economic and geographical determinants. The results indicate the importance of health policy measures. These should be used in a more targeted manner in the regions in order to increase utilization of skin cancer screening.


Subject(s)
Early Detection of Cancer , Skin Neoplasms , Germany/epidemiology , Humans , Multivariate Analysis , National Health Programs , Skin Neoplasms/diagnosis , Skin Neoplasms/epidemiology
6.
Sci Rep ; 8(1): 8705, 2018 06 07.
Article in English | MEDLINE | ID: mdl-29880845

ABSTRACT

Predators influence the behaviour of prey and by doing so they potentially reduce pathogen transmission by a vector. Arthropod predators have been shown to reduce the consumption of plant biomass by pest herbivores, but their cascading non-consumptive effect on vector insects' feeding behaviour and subsequent pathogen transmission has not been investigated experimentally before. Here we experimentally examined predator-mediated pathogen transmission mechanisms using the plant pathogen Wheat Dwarf Virus that is transmitted by the leafhopper, Psammotettix alienus. We applied in situ hybridization to localize which leaf tissues were infected with transmitted virus DNA in barley host plants, proving that virus occurrence is restricted to phloem tissues. In the presence of the spider predator, Tibellus oblongus, we recorded the within leaf feeding behaviour of the herbivore using electrical penetration graph. The leafhopper altered its feeding behaviour in response to predation risk. Phloem ingestion, the feeding phase when virus acquisition occurs, was delayed and was less frequent. The phase when pathogen inoculation takes place, via the secretion of virus infected vector saliva, was shorter when predator was present. Our study thus provides experimental evidence that predators can potentially limit the spread of plant pathogens solely through influencing the feeding behaviour of vector organisms.


Subject(s)
Geminiviridae , Hemiptera/virology , Hordeum/virology , Insect Vectors/virology , Models, Biological , Plant Diseases/virology , Spiders/physiology , Animals , DNA, Viral/metabolism , Hordeum/metabolism , Plant Leaves/metabolism , Predatory Behavior
7.
J Eur Acad Dermatol Venereol ; 32(11): 1906-1913, 2018 Nov.
Article in English | MEDLINE | ID: mdl-29633375

ABSTRACT

BACKGROUND: Skin cancer being the most common cancer in Germany has shown increasing incidence in the past decade. Since mostly caused by excessive UV exposure, skin cancer is largely related to behaviour. So far, the impact of regional and sociodemographic factors on the development of skin cancer in Germany is unclear. OBJECTIVES: This study aimed to investigate the association of potential predictive factors with the prevalence of skin cancers in Germany. METHODS: Nationwide ambulatory care claims data from persons insured in statutory health insurances (SHI) with malignant melanoma (MM, ICD-10 C43) and non-melanocytic skin cancer (NMSC, ICD-10 C44) in the years 2009-2015 were analysed. In addition, sociodemographic population data and satellite-based UV and solar radiation data were associated. Descriptive and multivariate (spatial) statistical analyses (e.g. Bayes' smoothing) were conducted on county level. RESULTS: Data from 70.1 million insured persons were analysed. Age-standardized prevalences per 100 000 SHI insured persons for MM and NMSC were 284.7 and 1126.9 in 2009 and 378.5 and 1708.2 in 2015. Marked regional variations were observed with prevalences between 32.9% and 51.6%. Multivariate analysis shows among others statistically significant positive correlations between higher income and education, and MM/NMSC prevalence. CONCLUSION: Prevalence of MM and NMSC in Germany shows spatio-temporal dynamics. Our results demonstrate that regional UV radiation, sunshine hours and sociodemographic factors have significant impact on skin cancer prevalence in Germany. Individual behaviour obviously is a major determinant which should be subject to preventive interventions.


Subject(s)
Skin Neoplasms/epidemiology , Skin Neoplasms/pathology , Sunlight/adverse effects , Ultraviolet Rays/adverse effects , Adult , Age Distribution , Aged , Bayes Theorem , Carcinoma, Basal Cell/epidemiology , Carcinoma, Basal Cell/pathology , Carcinoma, Squamous Cell/epidemiology , Carcinoma, Squamous Cell/pathology , Databases, Factual , Demography , Female , Germany/epidemiology , Humans , Insurance Claim Review , Linear Models , Male , Melanoma/epidemiology , Melanoma/pathology , Middle Aged , Multivariate Analysis , Prevalence , Retrospective Studies , Risk Assessment , Rural Population , Sex Distribution , Socioeconomic Factors , Urban Population
8.
Nano Lett ; 17(10): 6360-6365, 2017 10 11.
Article in English | MEDLINE | ID: mdl-28895745

ABSTRACT

Stacking atomic monolayers of semiconducting transition metal dichalcogenides (TMDs) has emerged as an effective way to engineer their properties. In principle, the staggered band alignment of TMD heterostructures should result in the formation of interlayer excitons with long lifetimes and robust valley polarization. However, these features have been observed simultaneously only in MoSe2/WSe2 heterostructures. Here we report on the observation of long-lived interlayer exciton emission in a MoS2/MoSe2/MoS2 trilayer van der Waals heterostructure. The interlayer nature of the observed transition is confirmed by photoluminescence spectroscopy, as well as by analyzing the temporal, excitation power, and temperature dependence of the interlayer emission peak. The observed complex photoluminescence dynamics suggests the presence of quasi-degenerate momentum-direct and momentum-indirect bandgaps. We show that circularly polarized optical pumping results in long-lived valley polarization of interlayer exciton. Intriguingly, the interlayer exciton photoluminescence has helicity opposite to the excitation. Our results show that through a careful choice of the TMDs forming the van der Waals heterostructure it is possible to control the circular polarization of the interlayer exciton emission.

9.
J Phys Condens Matter ; 28(1): 015301, 2016 Jan 13.
Article in English | MEDLINE | ID: mdl-26648394

ABSTRACT

We report on vacuum ultraviolet (VUV) excited photoluminescence (PL) spectra emitted from a chemical vapor deposited MoS2 few-layered film. The excitation spectrum was recorded by monitoring intensities of PL spectra at ~1.9 eV. A strong wide excitation band peaking at 7 eV was found in the excitation. The PL excitation band is most intensive at liquid helium temperature and completely quenched at 100 K. Through first-principles calculations of photoabsorption in MoS2, the excitation was explicated and attributed to transitions of electrons from p- and d- type states in the valence band to the d- and p-type states in the conduction band. The obtained photon-in/photon-out results clarify the excitation and emission behavior of the low dimensional MoS2 when interacting with the VUV light sources.

10.
Nano Lett ; 15(5): 3431-8, 2015 May 13.
Article in English | MEDLINE | ID: mdl-25928894

ABSTRACT

Ultrathin nanopore membranes based on 2D materials have demonstrated ultimate resolution toward DNA sequencing. Among them, molybdenum disulfide (MoS2) shows long-term stability as well as superior sensitivity enabling high throughput performance. The traditional method of fabricating nanopores with nanometer precision is based on the use of focused electron beams in transmission electron microscope (TEM). This nanopore fabrication process is time-consuming, expensive, not scalable, and hard to control below 1 nm. Here, we exploited the electrochemical activity of MoS2 and developed a convenient and scalable method to controllably make nanopores in single-layer MoS2 with subnanometer precision using electrochemical reaction (ECR). The electrochemical reaction on the surface of single-layer MoS2 is initiated at the location of defects or single atom vacancy, followed by the successive removals of individual atoms or unit cells from single-layer MoS2 lattice and finally formation of a nanopore. Step-like features in the ionic current through the growing nanopore provide direct feedback on the nanopore size inferred from a widely used conductance vs pore size model. Furthermore, DNA translocations can be detected in situ when as-fabricated MoS2 nanopores are used. The atomic resolution and accessibility of this approach paves the way for mass production of nanopores in 2D membranes for potential solid-state nanopore sequencing.

11.
Vet Rec ; 174(8): 196, 2014 Feb 22.
Article in English | MEDLINE | ID: mdl-24482210

ABSTRACT

Different test series have been developed and used to measure behaviour in shelter dogs in order to reveal individuals not suitable for re-homing due to their aggressive tendencies. However, behavioural tests previously validated on pet dogs seem to have relatively low predictability in the case of shelter dogs. Here, we investigate the potential effects of (1) timing of the behaviour testing and (2) presence of a human companion on dogs' aggressive behaviour. In Study I, shelter dogs (n=25) showed more aggression when tested in a short test series two weeks after they had been placed in the shelter compared to their responses in the same test performed 1-2 days after arrival. In Study II, the occurrence of aggressive behaviour was more probable in pet dogs (n=50) in the presence than in the absence of their passive owner. We conclude that the sensitivity of aggression tests for shelter dogs can be increased by running the test in the presence of a caretaker, and after some period of acclimatisation to the new environment. This methodology could also provide better chances for successful adoption.


Subject(s)
Aggression/psychology , Behavior, Animal , Dogs/psychology , Housing, Animal , Human-Animal Bond , Animals , Female , Humans , Male , Reproducibility of Results , Time Factors
12.
Nat Nanotechnol ; 8(12): 939-45, 2013 Dec.
Article in English | MEDLINE | ID: mdl-24240429

ABSTRACT

Solid-state nanopores can act as single-molecule sensors and could potentially be used to rapidly sequence DNA molecules. However, nanopores are typically fabricated in insulating membranes that are as thick as 15 bases, which makes it difficult for the devices to read individual bases. Graphene is only 0.335 nm thick (equivalent to the spacing between two bases in a DNA chain) and could therefore provide a suitable membrane for sequencing applications. Here, we show that a solid-state nanopore can be integrated with a graphene nanoribbon transistor to create a sensor for DNA translocation. As DNA molecules move through the pore, the device can simultaneously measure drops in ionic current and changes in local voltage in the transistor, which can both be used to detect the molecules. We examine the correlation between these two signals and use the ionic current measurements as a real-time control of the graphene-based sensing device.


Subject(s)
DNA/isolation & purification , Graphite/chemistry , Nanotechnology , DNA/chemistry , Nanopores , Nanotubes, Carbon/chemistry
14.
Epilepsy Res ; 104(1-2): 105-11, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23182414

ABSTRACT

The aim of this study was to use whole brain quantitative analysis to identify impaired white matter (WM) integrity using diffusion tensor imaging (DTI) in children with new-onset seizures. Thirty-five children with new-onset seizures and normal MRI were recruited. Twelve patients had generalized seizures, and 23 had partial seizures. Thirty-one healthy controls were also recruited. Whole brain fractional anisotropy (FA), apparent diffusion coefficient (ADC), radial diffusivity (RD) and axial diffusivity (AD) maps of patients were compared to controls, corrected for multiple comparisons. There was significantly reduced FA in left postcentral, elevated RD in left posterior cingulum and right external capsule, elevated AD in left middle temporal WM and left thalamus, and reduced AD in left anterior cingulum, left temporal, and right supramarginal WM in patients relative to controls. Patients with partial epilepsy showed elevated RD in bilateral posterior cingulum, increased AD in left middle frontal, reduced AD in left temporal, right parietal and right supramarginal WM. Patients with generalized epilepsy showed increased AD in right cerebellum, and reduced AD in left anterior cingulum and left middle temporal WM. The findings indicate that impaired WM integrity with abnormal myelin and axons is present in children with new-onset seizures.


Subject(s)
Diffusion Tensor Imaging/methods , Nerve Fibers, Myelinated/pathology , Seizures/pathology , Adolescent , Child , Female , Follow-Up Studies , Humans , Male , Nerve Fibers, Myelinated/metabolism , Retrospective Studies , Seizures/metabolism
15.
Nat Nanotechnol ; 6(3): 147-50, 2011 Mar.
Article in English | MEDLINE | ID: mdl-21278752

ABSTRACT

Two-dimensional materials are attractive for use in next-generation nanoelectronic devices because, compared to one-dimensional materials, it is relatively easy to fabricate complex structures from them. The most widely studied two-dimensional material is graphene, both because of its rich physics and its high mobility. However, pristine graphene does not have a bandgap, a property that is essential for many applications, including transistors. Engineering a graphene bandgap increases fabrication complexity and either reduces mobilities to the level of strained silicon films or requires high voltages. Although single layers of MoS(2) have a large intrinsic bandgap of 1.8 eV (ref. 16), previously reported mobilities in the 0.5-3 cm(2) V(-1) s(-1) range are too low for practical devices. Here, we use a halfnium oxide gate dielectric to demonstrate a room-temperature single-layer MoS(2) mobility of at least 200 cm(2) V(-1) s(-1), similar to that of graphene nanoribbons, and demonstrate transistors with room-temperature current on/off ratios of 1 × 10(8) and ultralow standby power dissipation. Because monolayer MoS(2) has a direct bandgap, it can be used to construct interband tunnel FETs, which offer lower power consumption than classical transistors. Monolayer MoS(2) could also complement graphene in applications that require thin transparent semiconductors, such as optoelectronics and energy harvesting.


Subject(s)
Disulfides/chemistry , Molybdenum/chemistry , Nanostructures/chemistry , Nanotechnology/instrumentation , Semiconductors/instrumentation , Transistors, Electronic , Equipment Design , Graphite/chemistry , Microscopy, Atomic Force/methods , Nanotechnology/methods , Nanotubes, Carbon/chemistry , Silicon/chemistry , Silicon Dioxide/chemistry , Surface Properties , Temperature
16.
Nanotechnology ; 22(12): 125706, 2011 Mar 25.
Article in English | MEDLINE | ID: mdl-21317494

ABSTRACT

Dichalcogenides with the common formula MX(2) are layered materials with electrical properties that range from semiconducting to superconducting. Here, we describe optimal imaging conditions for the optical detection of ultrathin, two-dimensional dichalcogenide nanocrystals containing single, double and triple layers of MoS(2), WSe(2) and NbSe(2). A simple optical model is used to calculate the contrast for nanolayers deposited on wafers with varying thicknesses of SiO(2). The model is extended for imaging using the green channel of a video camera. Using AFM and optical imaging we confirm that single layers of MoS(2) and WSe(2) can be detected on 90 and 270 nm SiO(2) using optical means. By measuring contrast under broadband green illumination we are also able to distinguish between nanostructures containing single, double and triple layers of MoS(2) and WSe(2.) We observe and discuss discrepancies in the case of NbSe(2).

17.
Transplant Proc ; 42(6): 2350-2, 2010.
Article in English | MEDLINE | ID: mdl-20692478

ABSTRACT

Spontaneous pneumomediastinum is a rare condition with nonspecific signs and symptoms. A 39-year-old underwent cadaver kidney transplantation. After an uncomplicated operation, progressive dyspnea of unknown origin developed. Findings at chest radiography suggested pneumomediastinum, which was confirmed at computed tomography. Esophageal or tracheal injury was ruled out. The rapidly developing atelectasis of the left lung necessitated urgent bronchoscopy, which revealed occlusion of the left main bronchus. After removal of the occluding mucus plug, the clinical symptoms immediately improved, and the spontaneous pneumomediastinum resolved within 3 days. Asymptomatic increase in airway secretions in patients receiving peritoneal dialysis may result in mucus plug formation during general anesthesia, which can cause spontaneous pneumomediastinum.


Subject(s)
Kidney Transplantation/adverse effects , Mediastinal Emphysema/etiology , Adult , Aorta, Abdominal/diagnostic imaging , Cadaver , Chest Pain/etiology , Female , Humans , Mediastinal Emphysema/diagnostic imaging , Peritoneal Dialysis , Pyelonephritis/etiology , Pyelonephritis/surgery , Radiography, Thoracic , Tissue Donors , Tomography, X-Ray Computed , Treatment Outcome
18.
Oral Microbiol Immunol ; 24(4): 314-8, 2009 Aug.
Article in English | MEDLINE | ID: mdl-19572894

ABSTRACT

INTRODUCTION: We investigated the potential role of human papillomaviruses (HPVs) in potentially malignant oral disorders, oral leukoplakia (OL) and oral lichen planus (OLP), and in oral squamous cell cancer (OSCC) in an Eastern Hungarian population with a high incidence of OSCC. METHODS: Excised tumor samples (65 OSCC patients) and exfoliated cells from potentially malignant lesions (from 44 and 119 patients with OL and OLP, respectively) as well as from healthy controls (72 individuals) were analysed. OLPs were classified based on clinical appearance, 61 patients had erosive-atrophic lesions (associated with higher malignancy risk, EA-OLP) and 58 had non-erosive non-atrophic lesions (with lower risk of becoming malignant, non-EA-OLP), respectively. Exfoliated cells collected from apparently healthy mucosa accompanied each lesion sample. HPV was detected by MY/GP polymerase chain reaction (PCR) and genotyped by restriction analysis of amplimers. Copy numbers in lesions were determined using real-time PCR. Prevalence rates, copy number distributions, and association with risk factors and diseases were analysed using chi-square test, t-test, and logistic regression, respectively. RESULTS: We detected HPVs significantly more frequently in lesions than in controls (P < or = 0.001 in all comparisons). HPV prevalence increased gradually with increasing severity of lesions (32.8, 40.9, and 47.7% in OLP, OL, and OSCC, respectively). Copy number distribution patterns roughly corresponded to prevalence rates, but OLP and OL were comparable. HPV prevalence differed significantly between EA-OLP and non-EA-OLP groups (42.6 vs. 22.4%); EA-OLP group showed a prevalence similar to that found in OL. CONCLUSION: HPVs may be involved in the development or progression of not only OSCC but also of potentially malignant oral lesions.


Subject(s)
Carcinoma, Squamous Cell/virology , Leukoplakia, Oral/virology , Lichen Planus, Oral/virology , Mouth Mucosa/virology , Mouth Neoplasms/virology , Papillomaviridae/isolation & purification , Adult , Aged , Aged, 80 and over , Case-Control Studies , Cell Transformation, Neoplastic , Female , Humans , Hungary , Logistic Models , Male , Middle Aged , Polymerase Chain Reaction/methods , Risk Factors , Young Adult
19.
Osteoporos Int ; 20(4): 639-45, 2009 Apr.
Article in English | MEDLINE | ID: mdl-18704543

ABSTRACT

SUMMARY: LCT 13910 CC genotype is associated with lactose intolerance, a condition often resulting in reduced milk intake. Women with the CC genotype were found to have decreased serum calcium and reduced bone mineral density. INTRODUCTION: The CC genotype of the 13910 C/T polymorphism of the LCT gene is linked to lactose intolerance and low calcium intake. METHODS: We studied 595 postmenopausal women, including 267 osteoporotic, 200 osteopenic, and 128 healthy subjects. Genotyping, osteodensitometry, and laboratory measurements were carried out. RESULTS: Frequency of aversion to milk consumption was 20% for CC genotype and 10% for TT + TC genotypes (p = 0.03). The albumin-adjusted serum calcium was 2.325 +/- 0.09 mmol/L for CC genotype and 2.360 +/- 0.16 mmol/L for TT + TC genotypes (p = 0.031). Bone mineral density (BMD; Z score) was lower in the CC than TT + TC genotypes, respectively, at the radius (0.105 +/- 1.42 vs 0.406 +/- 1.32; p = 0.038), at the total hip (-0.471 +/- 1.08 vs -0.170 +/- 1.09; p = 0.041), and at the Ward's triangle (-0.334 +/- 0.87 vs -0.123 +/- 0.82; p = 0.044). CONCLUSION: LCT 13910 C/T polymorphism is associated with decreased serum calcium level and lower BMD in postmenopausal women.


Subject(s)
Bone Density/genetics , Bone Diseases, Metabolic/etiology , Calcium/blood , Lactase-Phlorizin Hydrolase/genetics , Lactose Intolerance/complications , Absorptiometry, Photon/methods , Aged , Anthropometry , Bone Diseases, Metabolic/blood , Bone Diseases, Metabolic/physiopathology , Female , Genotype , Humans , Lactose Intolerance/blood , Lactose Intolerance/genetics , Lactose Intolerance/physiopathology , Middle Aged , Osteoporosis, Postmenopausal/blood , Osteoporosis, Postmenopausal/etiology , Osteoporosis, Postmenopausal/physiopathology , Polymorphism, Single Nucleotide
20.
Langmuir ; 24(12): 6176-81, 2008 Jun 17.
Article in English | MEDLINE | ID: mdl-18494514

ABSTRACT

Central to the biological function of microtubules is their ability to modify their length which occurs by addition and removal of subunits at the ends of the polymer, both in vivo and in vitro. This dynamic behavior is strongly influenced by temperature. Here, we show that the lateral interaction between tubulin subunits forming microtubule is strongly temperature dependent. Microtubules deposited on prefabricated substrates were deformed in an atomic force microscope during imaging, in two different experimental geometries. Microtubules were modeled as anisotropic, with the Young's modulus corresponding to the resistance of protofilaments to stretching and the shear modulus describing the weak interaction between the protofilaments. Measurements involving radial compression of microtubules deposited on flat mica confirm that microtubule elasticity depends on the temperature. Bending measurements performed on microtubules deposited on lithographically fabricated substrates show that this temperature dependence is due to changing shear modulus, implying that the lateral interaction between the protofilaments is strongly determined by the temperature. These measurements are in good agreement with previously reported measurements of the disassembly rate of microtubules, demonstrating that the mechanical and dynamic properties of microtubules are closely related.


Subject(s)
Microtubules/chemistry , Animals , Biochemistry/methods , Cattle , Cryoelectron Microscopy , Dimerization , Elasticity , Microscopy, Atomic Force , Microscopy, Electron, Transmission , Microtubule-Associated Proteins/chemistry , Molecular Conformation , Surface Properties , Temperature , Tubulin/chemistry
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