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1.
Autism Res Treat ; 2017: 1048302, 2017.
Article in English | MEDLINE | ID: mdl-28804650

ABSTRACT

It has been suggested that the second (2D, index finger) to fourth (4D, ring finger) digit ratio, 2D : 4D, may be a biomarker for the risk of developing autism. The aim of the current study was to determine the usefulness of the 2D : 4D digit ratio as biomarker for autistic traits. N = 401 healthy young volunteers participated in the study. For both hands, digit lengths were measured using digital Vernier calipers. In addition to demographics, the Autism Spectrum Quotient (AQ) questionnaire was completed, comprised of five subscales, assessing "social insights and behavior," "attention switching," "communication," "imagination," and "attention to detail." Overall, no significant correlations were observed between the AQ total score, its subscales, and the 2D : 4D digit ratio. For women, the left hand 2D : 4D digit ratio correlated significantly with the subscale score "communication" (r = -0.142; p = 0.036). For men, a significant positive correlation was found between the left 2D : 4D digit ratio and the total AQ score (r = 0.157; p = 0.042) and AQ subscale "attention switching" (r = 0.182; p = 0.017). In conclusion, gender specific associations between the 2D : 4D digit ratio and specific autism traits were observed, which were stronger in men than in women. Future studies should be conducted in patients that are formally diagnosed with autism.

2.
J Back Musculoskelet Rehabil ; 30(3): 591-596, 2017.
Article in English | MEDLINE | ID: mdl-28035907

ABSTRACT

BACKGROUND: In case of complex vertebral fractures, posterior fixation is often required for correction of deformity and instability. Fixation is commonly supported by balloon kyphoplasty (BKP) anterior. A development of BKP is radiofrequency-targeted vertebral augmentation (RF-TVA), which leads to comparable results for augmentation and pain relief. OBJECTIVE: This prospective study evaluates the outcome of posterior fixation combined with RF-TVA or BKP, respectively. METHODS: VAS, ODI, kyphosis angle and vertebral height of 44 patients were evaluated preoperatively, 3 and 12 months postoperatively. RESULTS: Both treatments improved vertebral height and kyphosis angle. At 12 months, vertebral height restoration was still significantly better in the BKP group (p < 0.001) and the improvement of kyphosis angle was comparable between both groups (p = 0.71). VAS and ODI improvements were significantly better in the RF-TVA group (p < 0.001). 8% of BKP patients had cement extravasations, compared to 10.5% in the RF-TVA group (p = 1.0). CONCLUSIONS: Combining posterior fixation with RF-TVA leads to better results of VAS and ODI, whereas the vertebral height restoration was favorable for patients treated with BKP. Cement leakage was comparable between both groups. It was asymptomatic and within reported ranges. Limitations of this study are the patient number and different stabilization instrumentation.


Subject(s)
Fractures, Compression/surgery , Kyphoplasty/methods , Lumbar Vertebrae/injuries , Spinal Fractures/surgery , Aged , Aged, 80 and over , Bone Cements , Female , Humans , Kyphoplasty/instrumentation , Kyphosis , Male , Middle Aged , Prospective Studies , Spine , Treatment Outcome
3.
Eur J Clin Nutr ; 71(3): 372-376, 2017 03.
Article in English | MEDLINE | ID: mdl-27924806

ABSTRACT

BACKGROUND/OBJECTIVES: In obese subjects, reduced muscle mass and strength are associated with impaired functional and metabolic capacity. We therefore investigated the association between abdominal fat distribution, fat mass index and maximum muscle strength of upper and lower extremities in obese patients. SUBJECTS/METHODS: One hundred and fifty five outpatients with a body mass index (BMI)⩾30 kg/m2 (105 women; 45.1±14.6 years; BMI 43.5±8.2 kg/m2) were included in the study. Grip and knee extension strength were measured with dynamometers. Using bioelectric impedance analysis, fat-free mass and fat mass indices (FFMI, FMI) were calculated. The influence of age, weight, FFMI, FMI and waist-to-hip ratio (WHR) on grip and knee extension strength was investigated in a risk factor-adjusted regression analysis. RESULTS: BMI did not correlate with hand grip or knee extension strength. The regression model confirmed a positive effect of higher weight on strength parameters; however, increased FMI was shown to have a negative effect on strength in both sexes (women, knee: ß: -1.495, confidence interval (CI): -2.075 to -0.0914, P<0.0001; women, hand: ß: -0.714, CI: -1.156 to -0.273, P=0.002; men, hand: ß:-1.448, CI: -2.618 to -0.278, P=0.016). Although increased WHR positively influenced knee extension strength (ß: 24.286, CI: 0.728-47.844, P<0.043), it did not affect grip strength in women. This association was not seen in men. CONCLUSIONS: Body fat distribution rather than BMI alone needs to be considered when evaluating strength parameters in obesity. As the relationship between obesity and strength of the upper versus lower extremities differs, grip strength cannot be considered an indicator of whole body strength in obese individuals.


Subject(s)
Abdominal Fat/physiopathology , Arm/physiopathology , Leg/physiopathology , Muscle Strength , Body Composition , Body Mass Index , Body Weight , Cross-Sectional Studies , Electric Impedance , Female , Hand Strength , Humans , Male , Middle Aged , Obesity/physiopathology , Risk Factors , Waist-Hip Ratio
4.
Z Orthop Unfall ; 153(4): 415-22, 2015 Aug.
Article in German | MEDLINE | ID: mdl-26016523

ABSTRACT

BACKGROUND: Lumbar spinal canal stenosis is commonly treated by dorsal decompression. However, resection of posterior elements increases the biomechanical instability and may lead to further complications. In order to prevent this, fusion of the involved segments is often performed. But further complications may be associated with this, for example, highly reduced flexibility. In order to overcome fusion-related problems, dynamic stabilisation devices, like the new LimiFlex™ Paraspinous Tension Band (PSB), have been developed. This prospective study compares dorsal decompression without stabilisation and dorsal decompression with stabilisation using the PSB in patients with lumbar canal stenosis. METHODS: Sixty-three patients with stenosis involving one or two lumbar vertebral levels were treated with dorsal decompression. Forty received the PSB following decompression surgery. Back, hip and leg pain as well as patient's degree of disability were assessed preoperatively and at 3, 6 and 12 months postoperatively for all patients. Evaluations were conducted using the visual analogue scale (VAS) and the Oswestry disability index (ODI). Adverse events during the study period were evaluated. RESULTS: Patients who received the PSB experienced a better pain relief and improvement in disability compared to patients who received treatment through decompression only. A significant difference of VAS and ODI development was found between both groups when treating two vertebral levels. Furthermore, the total number of adverse events was lower in the PSB group compared to the decompression group. CONCLUSION: Dynamic stabilisation using the PSB delivers better results in terms of VAS and ODI values when compared to only dorsal decompression. In addition, it is also associated with a lower number of complications. The PSB is most favourable when 2 levels are treated.


Subject(s)
Decompression, Surgical/instrumentation , Lumbar Vertebrae/surgery , Pain/prevention & control , Spinal Fusion/instrumentation , Spinal Stenosis/surgery , Aged , Combined Modality Therapy/instrumentation , Combined Modality Therapy/methods , Decompression, Surgical/methods , Equipment Failure Analysis , Female , Humans , Male , Middle Aged , Pain/diagnosis , Pain/etiology , Pain Measurement , Prosthesis Design , Spinal Fusion/methods , Spinal Stenosis/complications , Spinal Stenosis/diagnosis , Treatment Outcome
5.
RSC Adv ; 5(66): 53172-53179, 2015 Jul 19.
Article in English | MEDLINE | ID: mdl-27019703

ABSTRACT

Carbohydrate-lectin interactions dictate a range of signalling and recognition processes in biological systems. The exploitation of these, particularly for diagnostic applications, is complicated by the inherent promiscuity of lectins along with their low affinity for individual glycans which themselves are challenging to access (bio)synthetically. Inspired by how a 'tongue' can discriminate between hundreds of flavours using a minimal set of multiplexed sensors and a training algorithm, here individual lectins are 'profiled' based on their unique binding profile (barcode) to a range of monosaccharides. By comparing the relative binding of a panel of 5 lectins to 3 monosaccharide-coated surfaces, it was possible to generate a training algorithm that enables correct identification of lectins, even those with similar glycan preferences. This is demonstrated to be useful for discrimination between the cholera and ricin toxin lectins showing the potential of this minimalist approach for exploiting glycan complexity.

6.
Z Orthop Unfall ; 151(6): 632-7, 2013 Dec.
Article in German | MEDLINE | ID: mdl-24347417

ABSTRACT

PURPOSE: Radiofrequency kyphoplasty is an advancement of the balloon kyphoplasty and offers comparable results with a shorter operation time and a lower risk of cement leakage. This prospective study investigates the outcome of radiofrequency kyphoplasty in combination with posterior fixation by a cement-augmented screw system. Accordingly, statistical analyses of the treatment data were performed. MATERIALS AND METHODS: 19 patients (mean age: 74.5 ± 7.2 years) with osteoporotic vertebral burst fractures were included in the study. All of them required a surgical intervention for treating the fracture. Thereby, the vertebrae were augmented by radiofrequency kyphoplasty and a posterior fixation by cement-augmentable screws was performed. To evaluate the effectiveness and safety of the procedure, pain was measured with the visual analog scale (VAS) and functional impairment was analysed by measuring the Oswestry disability index (ODI). Furthermore, a radiographic analysis of the anterior and medial height of the vertebrae and the degree of kyphosis were undertaken. All data were recorded preoperatively, 3 to 4 days postoperatively, 3 months postoperatively and 6 months postoperatively and any additionally occurring cement leakage was documented. RESULTS: The treatment showed a significant reduction of pain and improvement of the functional impairment at the 3 to 4 days postoperative evaluation (pVAS < 0.001, pODI < 0.001). The further follow-ups demonstrated an ongoing improvement of the VAS and ODI from each measurement to the next (pVAS_post-3 M < 0.001, pVAS_3 M-6 M = 0.17, pODI_post-3 M < 0.001, pODI_3 M-6 M = 0.004). The height of the vertebrae was significantly improved after the surgery (p_anterior < 0.001, p_medial < 0.001) and reduced slightly from follow-up to follow-up, but still remained higher than the preoperative value. The degree of kyphosis was also significantly improved after the surgery (p < 0.001), whereby a significant deterioration was shown at the following examinations (p_post-3 M = 0.023, p_3 M-6 M = 0.016). But even as the height decreased the degree of kyphosis was still improved in relation to the preoperative values. During the surgery cement leakage occurred in 3 cases (15.79 %). CONCLUSION: Radiofrequency kyphoplasty is a safe and effective procedure for the treatment of vertebral compression fractures in combination with the use of posterior fixation by cement-augmentable screws with an acceptable rate of cement leakage.


Subject(s)
Catheter Ablation/methods , Fracture Fixation, Internal/methods , Fractures, Compression/surgery , Kyphoplasty/methods , Spinal Fractures/surgery , Aged , Combined Modality Therapy/methods , Female , Fracture Healing , Fractures, Compression/diagnosis , Humans , Male , Spinal Fractures/diagnosis , Treatment Outcome
7.
Z Orthop Unfall ; 150(4): 392-6, 2012 Sep.
Article in German | MEDLINE | ID: mdl-22918825

ABSTRACT

OBJECTIVE: An evaluation of treatment protocols was used to expand the documentation of efficacy and safety of radiofrequency kyphoplasty (RFK). Additionally, a comparison of this new and innovative procedure with conservative treatment was carried out. PATIENTS, MATERIALS AND METHODS: Patients with painful osteoporotic vertebral fractures according to the common findings in an orthopaedic university hospital were included in the comparison study in which the indication for surgical intervention action according to the DVO guidelines was interdisciplinary confirmed. For the comparison group, patients with the same clinical and radiological findings were recruited who rejected a surgical intervention. For surgery, the StabiliT® Vertebral Augmentation System for a radiofrequency kyphoplasty by the company DFine was used. The cement was injected with a "multiplex controller". Thus, the results of the new method were compared to those of a group that was treated conservatively. RESULTS: The radiofrequency kyphoplasty (n = 114) resulted in an average decrease of VAS scores by almost 60 mm, which increased during the follow-up. Similarly, the Oswestry scores showed a marked improvement by 46 % points after 6 weeks. The mean increase in vertebral body height was 2.8 mm after radiofrequency kyphoplasty. In the conservatively treated group only very small changes compared to the initial findings were registered during the 6-week observation period. Accordingly, 33 of 67 patients decided after 6 weeks for surgery, which led to corresponding improvements (VAS, Oswestry, vertebral body height). Noteworthy is the low rate of cement leakage in the radiofrequency kyphoplasty group of 6 % (n = 7). CONCLUSIONS: Radiofrequency kyphoplasty offers a secure superiority over conservative treatment regarding clinical efficacy. In addition, the fractured vertebrae can be better targeted and erected, a longer processing time of the cement is ensured, a high interdigitation of the cement with the bone is guaranteed, the rate of cement leakage is low, the risk of radiation for the surgeon is minimised, and the operation time is shortened.


Subject(s)
Catheter Ablation/statistics & numerical data , Fractures, Compression/epidemiology , Fractures, Compression/therapy , Kyphoplasty/statistics & numerical data , Spinal Fractures/epidemiology , Spinal Fractures/therapy , Aged , Aged, 80 and over , Female , Germany/epidemiology , Humans , Male , Middle Aged , Prevalence , Prospective Studies , Treatment Outcome
8.
Z Orthop Unfall ; 150(6): 572-8, 2012 Dec.
Article in German | MEDLINE | ID: mdl-23296554

ABSTRACT

BACKGROUND: As a further alternative to previously used vertebral augmentation methods, the Kiva VCF Treatment System® was clinically investigated. MATERIAL AND METHODS: The pilot study included 24 patients (mean age 74 years, 34 vertebrae). RESULTS: During an operation period of 16.6 minutes on average 2.2 ± 1 mL of PMMA cement were injected. 87 % of patients were satisfied or very satisfied with this treatment. In 2 cases leakage of cement has been registered. The pain intensity was already reduced after 7 days to 69.5 mm (VAS scale 0-100). After 30 days, the difference from baseline was 76 mm. Significant improvements have also been shown in the Oswestry Score (functional ability), physical performance and mental well-being. CONCLUSION: On the basis of these results, the new augmentation can be described as being effective in the treatment of painful vertebral fractures.


Subject(s)
Bone Cements/therapeutic use , Fractures, Compression/therapy , Internal Fixators , Pain/prevention & control , Spinal Fractures/therapy , Vertebroplasty/instrumentation , Aged , Equipment Failure Analysis , Female , Fractures, Compression/complications , Humans , Male , Pain/etiology , Pilot Projects , Prosthesis Design , Spinal Fractures/complications , Treatment Outcome , Vertebroplasty/methods
9.
Z Orthop Unfall ; 150(2): 198-204, 2012 Apr.
Article in German | MEDLINE | ID: mdl-22065377

ABSTRACT

OBJECTIVE: By evaluations of treatment protocols, the documentation of balloon kyphoplasty regarding efficacy, duration of action and safety should be expanded. In addition, the evaluations should help to clarify the differences in balloon kyphoplasty for patients with vertebral fractures concerning efficacy and safety in relation to the underlying diseases: osteoporosis, bone metastases or myeloma. MATERIAL AND METHODS: In order to reposition the endplates of the vertebrae a balloon was inserted after placement of the working channels. After removal of the balloon, the resulting caverns were filled with PMMA. The radiological and clinical follow-up examinations were carried out over a period of up to 3 years. The clinical and radiological findings before and after treatment at specified visits were transferred to a statistical programme and evaluated. RESULTS: The comparisons of the postoperative results according to the initial diagnosis (metastases: n = 222, osteoporosis: n = 122, myeloma: n = 122) demonstrated significant differences with respect to the cement leakage (14 %, 5 %, 7.5 %), but in all cases without any clinical relevance. The small differences related to the reduction in pain intensity (VAS > 50 mm in each group) after surgery were up to 12 months with no clinical significance. Also in the Oswestry score no differences between the 3 groups were registered. In the case of osteoporosis patients, due to the lower starting position a more significant increase of vertebral body height could be achieved by the kyphoplasty than in the comparison groups of patients with metastases or myeloma (∅ 3.1 mm vs. 0.4-0.5 mm; P < 0.001). Consequently, the kyphosis angle decreased in the osteoporotic group also more strongly than in the comparison groups. CONCLUSIONS: It is evident that the pain relief in the vast majority of cases started immediately after surgery. Additionally, a significant improvement in functioning (Oswestry score) was registered. Both clinical parameters - as far as they could be checked - showed a steady degree of improvement over a period of at least 3 years. This comparative analysis led to the conclusion that balloon kyphoplasty can be successfully applied indiscriminately in patients with vertebral fractures as a result of osteoporosis and also to fractures associated with bone metastases or with myeloma.


Subject(s)
Catheterization/statistics & numerical data , Kyphoplasty/statistics & numerical data , Multiple Myeloma/epidemiology , Multiple Myeloma/secondary , Osteoporosis/epidemiology , Spinal Fractures/epidemiology , Spinal Fractures/therapy , Adult , Aged , Aged, 80 and over , Comorbidity , Female , Germany , Humans , Male , Middle Aged , Prevalence , Risk Assessment , Risk Factors , Treatment Outcome
10.
Org Biomol Chem ; 9(8): 3011-9, 2011 Apr 21.
Article in English | MEDLINE | ID: mdl-21380438

ABSTRACT

In this study a diverse range of purified cobalt containing nitrile hydratases (NHases, EC 4.2.1.84) from Rhodopseudomonas palustris HaA2 (HaA2), Rhodopseudomonas palustris CGA009 (009), Sinorhizobium meliloti 1021 (1021), and Nitriliruptor alkaliphilus (iso2), were screened for the first time for their enantioselectivity towards a broad range of chiral nitriles. Enantiomeric ratios of >100 were found for the NHases from HaA2 and CGA009 on 2-phenylpropionitrile. In contrast, the Fe-containing NHase from the well-characterized Rhodococcus erythropolis AJ270 (AJ270) was practically aselective with a range of different α-phenylacetonitriles. In general, at least one bulky group in close proximity to the α-position of the chiral nitriles seemed to be necessary for enantioselectivity with all NHases tested. Nitrile groups attached to a quaternary carbon atom were only reluctantly accepted and showed no selectivity. Enantiomeric ratios of 80 and >100 for AJ270 and iso2, respectively, were found for the pharmaceutical intermediate naproxennitrile, and 3-(1-cyanoethyl)benzoic acid was hydrated to the corresponding amide by iso2 with an enantiomeric ratio of >100.


Subject(s)
Acetonitriles/chemistry , Actinobacteria/enzymology , Hydro-Lyases/metabolism , Rhodopseudomonas/enzymology , Sinorhizobium meliloti/enzymology , Acetonitriles/metabolism , Hydro-Lyases/isolation & purification , Stereoisomerism , Substrate Specificity
11.
J Virol ; 77(17): 9369-77, 2003 Sep.
Article in English | MEDLINE | ID: mdl-12915552

ABSTRACT

Mouse mammary tumor virus (MMTV) infects the host via mucosal surfaces and exploits the host immune system for systemic spread and chronic infection. We have tested a neutralizing rat monoclonal antibody specific for the retroviral envelope glycoprotein gp52 for its efficiency in preventing acute and chronic mucosal and systemic infection. The antibody completely inhibits the superantigen response and chronic viral infection following systemic or nasal infection. Surprisingly however, the antibody only partially inhibits the early infection of antigen-presenting cells in the draining lymph node. Despite this initially inefficient protection from infection, superantigen-specific B- and T-cell responses and systemic viral spread are abolished, leading to complete clearance of the retroviral infection and hence interruption of the viral life cycle. In conclusion, systemic neutralizing monoclonal antibodies can provide an efficient protection against chronic retroviral amplification and persistence.


Subject(s)
Mammary Tumor Virus, Mouse/growth & development , Mammary Tumor Virus, Mouse/immunology , Animals , Antibodies, Monoclonal/administration & dosage , Antibodies, Viral/administration & dosage , Antigens, Viral, Tumor/genetics , Antigens, Viral, Tumor/immunology , B-Lymphocytes/immunology , B-Lymphocytes/pathology , Base Sequence , Cell Differentiation , DNA, Viral/genetics , Female , Immunity, Mucosal , Immunization, Passive , Mammary Neoplasms, Experimental/immunology , Mammary Neoplasms, Experimental/prevention & control , Mammary Tumor Virus, Mouse/genetics , Mice , Mice, Inbred BALB C , Neutralization Tests , Rats , Rats, Inbred Lew , Retroviridae Infections/immunology , Retroviridae Infections/prevention & control , Tumor Virus Infections/immunology , Tumor Virus Infections/prevention & control
12.
Cereb Cortex ; 13(7): 793-805, 2003 Jul.
Article in English | MEDLINE | ID: mdl-12816895

ABSTRACT

Face perception, recognition and priming were examined with event-related functional magnetic resonance imaging (fMRI) and scalp event-related potentials (ERPs). Face perception was associated with haemodynamic increases in regions including bilateral fusiform and right superior temporal cortices, and a right posterior negativity (N170), most likely generated in the superior temporal region. Face recognition was associated with haemodynamic increases in fusiform, medial frontal and orbitofrontal cortices, and with a frontocentral positivity from 550 ms poststimulus. Face repetition was associated with a positivity from 400 to 600 ms and behavioural priming. Repetition of familiar faces was also associated with earlier onset of the ERP familiarity effect, and haemodynamic decreases in fusiform cortex. These data support a multi-component model of face-processing, with priming arising from more than one stage.


Subject(s)
Brain Mapping/methods , Cerebral Cortex/physiology , Evoked Potentials, Visual/physiology , Face , Pattern Recognition, Visual/physiology , Adult , Cerebral Cortex/blood supply , Evoked Potentials/physiology , Facial Expression , Female , Humans , Learning/physiology , Magnetic Resonance Imaging/methods , Male , Memory/physiology , Photic Stimulation/methods , Visual Perception/physiology
13.
Appl Opt ; 42(6): 908-21, 2003 Feb 20.
Article in English | MEDLINE | ID: mdl-12617205

ABSTRACT

We present results from an experiment to estimate the parameters of homogeneous, isotropic optical turbulence in the upper atmosphere. The balloon-borne experiment made high-resolution temperature measurements at seven points on a hexagonal grid for altitudes from 12,000 to 18,000 m. From the temperature data, we obtained index of refraction fluctuations that can be used to compute a sample-based estimate for a parameterized description of the spatial autocorrelation of the turbulence. The three parameters of interest were a proportionality constant Pc, the power-law parameter alpha, and the outer scale L0. The results obtained for Pc are within the expected range and agree well with independent measurements made from a standard rising thermosonde measurement made approximately simultaneously with the data collection. Values for a were in the range 1.52 < or = alpha < or = 1.73 were observed, which are significantly less than the power law used in the Kolmogorov and von Karman models, alpha = 1.833. Values observed for L0 were in the range 5 < or = L0 < or = 19 m. Evidence that alpha may be consistently less than that used in the Kolmogorov and von Karman models likely has the most significant implications for systems that must work in or through the tropopause.

14.
Mol Genet Genomics ; 267(5): 577-86, 2002 Jul.
Article in English | MEDLINE | ID: mdl-12172796

ABSTRACT

Many Agrobacterium T-DNA genes belong to a diverse family of T-DNA genes, the rolB family. These genes cause various growth abnormalities but their modes of action remain largely unknown. So far, none of the RolB-like proteins has been subjected to mutational analysis. The RolB-like oncoprotein 6B, which induces tumours on species such as Nicotiana glauca and Kalanchoe tubiflora, was chosen to investigate the role of the most conserved amino acid residues within the RolB family. We first determined which of the natural 6B variants had the strongest oncogenic activity; to this end, six 6b coding sequences (A- 6b, AB- 6b, C- 6b, CG- 6b, S- 6b and T- 6b) were placed under the control of the strong constitutive 2x35S promoter and compared for tumour induction on N. glauca, N. tabacum and K. daigremontiana. Oncogenicity increased in the order C- 6b/CG- 6b, A- 6b/AB- 6b, and S- 6b/T- 6b. The most conserved amino acid residues in the strongly oncogenic T-6B protein were mutated and shown to be required for oncogenicity and accumulation of the T-6B protein in planta but not in bacteria. Hybrids between T-6B and the weakly oncogenic A-6B protein revealed an additional oncogenic determinant required for the formation of large tumours.


Subject(s)
Bacterial Proteins/genetics , DNA Mutational Analysis , Oncogene Proteins/genetics , Rhizobium/genetics , beta-Glucosidase/genetics , Amino Acid Sequence , Genetic Variation , Molecular Sequence Data , Multigene Family , Mutation , Oncogene Proteins/physiology , Phylogeny , Rhizobium/physiology , Sequence Alignment , Nicotiana/physiology
15.
Appl Opt ; 41(15): 2800-8, 2002 May 20.
Article in English | MEDLINE | ID: mdl-12027166

ABSTRACT

We discuss a method of data reduction and analysis that has been developed for a novel experiment to detect anisotropic turbulence in the tropopause and to measure the spatial statistics of these flows. The experimental concept is to make measurements of temperature at 15 points on a hexagonal grid for altitudes from 12,000 to 18,000 m while suspended from a balloon performing a controlled descent. From the temperature data, we estimate the index of refraction and study the spatial statistics of the turbulence-induced index of refraction fluctuations. We present and evaluate the performance of a processing approach to estimate the parameters of an anisotropic model for the spatial power spectrum of the turbulence-induced index of refraction fluctuations. A Gaussian correlation model and a least-squares optimization routine are used to estimate the parameters of the model from the measurements. In addition, we implemented a quick-look algorithm to have a computationally nonintensive way of viewing the autocorrelation function of the index fluctuations. The autocorrelation of the index of refraction fluctuations is binned and interpolated onto a uniform grid from the sparse points that exist in our experiment. This allows the autocorrelation to be viewed with a three-dimensional plot to determine whether anisotropy exists in a specific data slab. Simulation results presented here show that, in the presence of the anticipated levels of measurement noise, the least-squares estimation technique allows turbulence parameters to be estimated with low rms error.

16.
J Neurosci ; 22(2): 523-8, 2002 Jan 15.
Article in English | MEDLINE | ID: mdl-11784798

ABSTRACT

The precise contribution of perirhinal cortex to human episodic memory is uncertain. Human intracranial recordings highlight a role in successful episodic memory encoding, but encoding-related perirhinal activation has not been observed with functional imaging. By adapting functional magnetic resonance imaging scanning parameters to maximize sensitivity to medial temporal lobe activity, we demonstrate that left perirhinal and hippocampal responses during word list encoding are greater for subsequently recalled than forgotten words. Although perirhinal responses predict memory for all words, successful encoding of initial words in a list, demonstrating a primacy effect, is associated with parahippocampal and anterior hippocampal activation. We conclude that perirhinal cortex and hippocampus participate in successful memory encoding. Encoding-related parahippocampal and anterior hippocampal responses for initial, remembered words most likely reflects enhanced attentional orienting to these positionally distinctive items.


Subject(s)
Hippocampus/physiology , Magnetic Resonance Imaging , Memory/physiology , Parahippocampal Gyrus/physiology , Verbal Behavior/physiology , Adult , Behavior/physiology , Brain Mapping/methods , Female , Hippocampus/anatomy & histology , Humans , Male , Mental Recall/physiology , Parahippocampal Gyrus/anatomy & histology , Photic Stimulation/methods , Temporal Lobe/anatomy & histology , Temporal Lobe/physiology
17.
Cereb Cortex ; 11(12): 1150-60, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11709486

ABSTRACT

Using event-related functional magnetic resonance imaging (fMRI), the neural correlates of memory encoding can be studied by contrasting item-related activity elicited in a study task according to whether the items are remembered or forgotten in a subsequent memory test. Previous studies using this approach have implicated the left prefrontal cortex in the successful encoding of verbal material into episodic memory when the study task is semantic in nature. In the current study, we asked whether the neural correlates of episodic encoding differ depending on type of study task. Seventeen volunteers participated in an event-related fMRI experiment in which at study, volunteers were cued to make either animacy or syllable judgements about words. A recognition memory test followed after a delay of approximately 15 min. For the animacy task, words that were subsequently remembered showed greater activation in left and medial prefrontal regions. For the syllable task, by contrast, successful memory for words was associated with activations in bilateral intraparietal sulcus, bilateral fusiform gyrus, right prefrontal cortex and left superior occipital gyrus. These findings suggest that the brain networks supporting episodic encoding differ according to study task.


Subject(s)
Magnetic Resonance Imaging , Parietal Lobe/physiology , Prefrontal Cortex/physiology , Verbal Learning/physiology , Adult , Female , Humans , Male , Recognition, Psychology/physiology
18.
Curr Biol ; 11(19): 1528-30, 2001 Oct 02.
Article in English | MEDLINE | ID: mdl-11591321

ABSTRACT

The neural correlates of memory encoding have been studied by contrasting neural activity elicited by items at the time of learning according to whether they were later remembered or forgotten [1]. Previous studies have focused on regions where neural activity is greater for subsequently remembered items [2-8]. Here, we describe regions where activity is greater for subsequently forgotten items. In two experiments that employed the same incidental learning task, activity in an overlapping set of cortical regions (posterior cingulate, inferior and medial parietal, and dorsolateral prefrontal) was associated with failure on a subsequent memory test.


Subject(s)
Brain Mapping , Memory, Short-Term/physiology , Neurons/physiology , Parietal Lobe/physiology , Prefrontal Cortex/physiology , Adult , Brain Mapping/methods , Female , Humans , Magnetic Resonance Imaging , Male , Task Performance and Analysis
19.
J Histochem Cytochem ; 49(10): 1211-20, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11561005

ABSTRACT

Culture of articular chondrocytes in alginate beads offers several advantages over culture in monolayer; cells retain their phenotype for 8 months or longer. Earlier studies of chondrocytes cultured in alginate concentrated on collagen and proteoglycan synthesis. However, gene expression by in situ hybridization (ISH) has not been investigated. The purposes of the present study on human chondrocytes were (a) to modify the ISH procedure for the alginate beads to examine the mRNA expression of alpha1 (II) procollagen, aggrecan, and two matrix metalloproteinases (MMP-3 and MMP-8) thought to be involved in cartilage matrix degradation, and (b) to compare expression in cultured chondrocytes with that in chondrocytes of intact human cartilage. The modifications made for ISH include the presence of CaCl2 and BaCl2 in the fixation and washing steps and exclusion of cetyl pyridinium chloride. By ISH we show that aggrecan, MMP-3, and MMP-8 are continuously expressed during 8 months of culture. The alpha1 (II) procollagen gene is expressed only during the first 2 months of culture and after 3 months its expression is undetectable, which is consistent with its absence in adult articular cartilage. By Western blotting, Type II collagen protein had been synthesized and deposited in both the cell-associated and further-removed matrix compartments at 7 and 14 days of culture. These data indicate that chondrocytes cultured in alginate beads could be preserved for immunohistochemistry and ISH and that culture of human chondrocytes in alginate beads may serve as a good model for studying cartilage-specific phenotype as well as factors that influence cartilage matrix turnover.


Subject(s)
Cartilage, Articular/metabolism , Chondrocytes/metabolism , Extracellular Matrix Proteins , RNA, Messenger/metabolism , Adult , Aggrecans , Blotting, Western , Cartilage, Articular/cytology , Cartilage, Articular/growth & development , Cells, Cultured , Humans , Immunohistochemistry , In Situ Hybridization , Infant, Newborn , Lectins, C-Type , Male , Matrix Metalloproteinase 3/genetics , Matrix Metalloproteinase 3/metabolism , Matrix Metalloproteinase 8/genetics , Matrix Metalloproteinase 8/metabolism , Procollagen/genetics , Procollagen/metabolism , Proteoglycans/genetics , Proteoglycans/metabolism
20.
Brain Res Cogn Brain Res ; 12(1): 11-8, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11489604

ABSTRACT

Event-related potentials (ERPs) were used to investigate whether the neural correlates of successful episodic encoding differ according to the nature of the study task. At study, 16 subjects were cued to make either animacy or alphabetic decisions about visually presented words. A recognition memory test with confidence judgements followed after a delay of 30 min. For the animacy task, words that were subsequently confidently recognised were associated with a positive-going ERP modulation. By contrast, for the alphabetic task, confident recognition was associated with a negative-going ERP modulation. Both types of subsequent memory effects started shortly after word onset. These findings suggest that the neural correlates of memory encoding differ qualitatively, rather than quantitatively, according to the nature of the study task. Episodic encoding thus seems to be supported by multiple, task-specific, neural systems. The early onset of these memory effects suggests that episodic encoding can be facilitated by processes that start before the onset of the to-be-encoded item.


Subject(s)
Electroencephalography , Memory/physiology , Psychomotor Performance/physiology , Adolescent , Adult , Cognition/physiology , Electrophysiology , Female , Humans , Male , Reaction Time/physiology
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