Publications by authors named "Frahm K"

Introduction/aims: Diabetic peripheral neuropathy affects small nerve fibers early, but adequate evaluation has proven difficult. One method for functional assessment of small nerve fiber function is the axon-reflex flare (ARF) response. This study aimed to 1) validate the histamine-induced ARF response in a nonselected population with diabetes, 2) compare the response to that induced by local heating, and 3) compare both methods to an established method (quantitative sensory testing) in a nonselected population with diabetes.

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Myocardial fibrosis is a major pathologic disorder associated with a multitude of cardiovascular diseases (CVD). The pathogenesis is complex and encompasses multiple molecular pathways. Integration of fibrosis-associated genes into the global MetaCore network of protein-protein interactions (PPI) offers opportunities to identify PPI with functional and therapeutic significance.

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Background: Spatial acuity concerns the ability to localize and discriminate sensory input and is often tested using the two-point discrimination threshold (2PDT). Sensitization of the pain system can affect the spatial acuity, but it is unclear how 2PDTs of different testing modalities are affected. The aim was to investigate if the 2PDTs for mechanical and heat stimulation at different intensities were modulated by topical capsaicin sensitization.

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We introduce and study a random matrix model of Kolmogorov-Zakharov turbulence in a nonlinear purely dynamical finite-size system with many degrees of freedom. For the case of a direct cascade, the energy and norm pumping takes place at low energy scales with absorption at high energies. For a pumping strength above a certain chaos border, a global chaotic attractor appears with a stationary energy flow through a Hamiltonian inertial energy interval.

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Article Synopsis
  • Cutaneous laser stimulation is used to study how our pain system perceives temperature and direction of stimuli, and this research aims to improve how directional discrimination is assessed using a laser.
  • Twenty healthy volunteers participated in experiments where thermal stimuli were delivered at different temperatures and directions, and their responses were measured for accuracy and intensity.
  • Results showed that using a closed-loop temperature control system led to significantly better discrimination of stimuli direction, especially in the lateral-medial directions, compared to an open-loop system, highlighting its potential for more effective assessments in pain research.
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We consider a model of an intelligent surfer moving on the Ulam network generated by a chaotic dynamics in the Chirikov standard map. This directed network is obtained by the Ulam method with a division of the phase space in cells of fixed size forming the nodes of a Markov chain. The goal quest for this surfer is to determine the network path from an initial node A to a final node B with minimal resistance given by the sum of inverse transition probabilities.

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We consider a system of linear oscillators, or quantum states, described by random matrix theory and analyze how its time evolution is affected by a nonlinear perturbation. Our numerical results show that above a certain chaos border a weak or moderate nonlinearity leads to a dynamical thermalization of a finite number of degrees of freedom with energy equipartition over linear eigenmodes as expected from the laws of classical statistical mechanics. The system temperature is shown to change in a broad range from positive to negative values, and the dependence of system characteristics on the initial injected energy is determined.

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Background: Infrared laser stimulation is a valuable tool in pain research, its primary application being the recording of laser-evoked brain potentials (LEPs). Different types of laser stimulators, varying in their skin penetrance, are likely to have a large influence on the LEPs, when stimulating different skin types. The aim of this study was to investigate how LEPs depend on laser type and skin location.

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  • Prostate cancer risk factors include age, race, and genetic variants, with the CREBRF gene showing notable alterations in Pacific Islanders, a group with high incidence rates.
  • Analysis revealed that 4.05% of prostate tumors had likely damaging CREBRF mutations, which correlated to significantly shorter survival rates—41.23 months for affected patients versus 131 months for those without.
  • In mice lacking CREBRF, there was decreased prostate cell growth and increased cell death, along with altered levels of specific circulating proteins, indicating CREBRF may be important for maintaining prostate health and regulating cancer progression.
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. Laser stimulators have been widely used in pain studies to selectively activate Aand C nociceptors without coactivation of mechanoreceptors. Temperature-controlled laser systems have been implemented with low-temperature variations during stimulations, however, these systems purely enabled stationary stimulation.

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Objective: To compare nociceptive event-related brain potentials elicited by a high-speed contact-thermode vs an infrared CO laser stimulator.

Methods: Contact heat-evoked potentials (CHEPs) and CO laser-evoked potentials (LEPs) were recorded in healthy volunteers using a high-speed contact-thermode (>200 °C/s) and a temperature-controlled CO laser. In separate experiments, stimuli were matched in terms of target surface temperature (55 °C) and intensity of perception.

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  • The nociceptive withdrawal reflex (NWR) is a protective response to harmful stimuli, and its strength is influenced by the spatial characteristics of the stimulus.
  • This study investigated how attention and distraction affect the NWR by examining muscle responses in healthy volunteers when stimulating different areas of the foot.
  • Results showed that distraction significantly amplified the NWR response compared to the baseline, while attention did not alter it, indicating that cognitive processes can modulate the spinal reflex pathways.
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Protein-protein interactions is a longstanding challenge in cardiac remodeling processes and heart failure. Here, we use the MetaCore network and the Google matrix algorithms for prediction of protein-protein interactions dictating cardiac fibrosis, a primary cause of end-stage heart failure. The developed algorithms allow identification of interactions between key proteins and predict new actors orchestrating fibroblast activation linked to fibrosis in mouse and human tissues.

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Spatial information of nociceptive stimuli applied in the skin of healthy humans is integrated in the spinal cord to determine the appropriate withdrawal reflex response. Double-simultaneous stimulus applied in different skin sites are integrated, eliciting a larger reflex response. The temporal characteristics of the stimuli also modulate the reflex, e.

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The two-point discrimination threshold (2PDT) has been used to investigate the integration of sensory information, especially in relation to spatial acuity. The 2PDT has been investigated for both innocuous mechanical stimuli and noxious thermal stimuli; however, previous studies used different stimulation modalities to compare innocuous and noxious stimuli. This study investigated the 2PDT in 19 healthy participants, using both thermal (laser) and mechanical stimulation modalities.

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Animal studies have previously shown that deep dorsal horn neurons play a role in the processing of spatial characteristics of nociceptive information in mammals. Human studies have supported the role of the spinal neurons; however, the mechanisms involved, and its significance, remain to be clarified. The aim of this study was to investigate spatial aspects of the spinal integration of concurrent nociceptive electrical stimuli in healthy humans using the Nociceptive Withdrawal Reflex (NWR) as an objective indication of spinal nociceptive processing.

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Cutaneous laser stimulation is a proficient tool to investigate the function of the nociceptive system. However, variations in laser-skin interactions, causes by different skin anatomies and laser wavelength, affects the robustness of nociceptor activation. Thus, thoroughly understanding how the skin is heated by a laser pulse is important to characterize the thermal response properties of nociceptors.

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Glucocorticoid signaling controls many key biological functions ranging from stress responses to affective states. The putative transcriptional coregulator CREB3 regulatory factor (CREBRF) reduces glucocorticoid receptor levels in vitro, suggesting that CREBRF may impact behavioral and physiological outputs. In the present study, we examined adult male and female mice with global loss of CREBRF (CrebrfKO) for anxiety-like behaviors and circulating glucocorticoids in response to various acute stress conditions.

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The excitability of large nerve fibers is reduced when their membrane potential is slowly depolarizing, i.e., the fibers display accommodation.

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English Wikipedia, containing more than five millions articles, has approximately eleven thousands web pages devoted to proteins or genes most of which were generated by the Gene Wiki project. These pages contain information about interactions between proteins and their functional relationships. At the same time, they are interconnected with other Wikipedia pages describing biological functions, diseases, drugs and other topics curated by independent, not coordinated collective efforts.

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Background: The directional discrimination is lower for painful laser heat compared to non-painful mechanical stimulation. The aim of the current study was to investigate how the directional discrimination of radiant heat stimulation depends on stimulation intensity and displacement velocity.

Methods: Fifteen healthy subjects were stimulated in the right volar forearm with a CO laser at intensities that were expected to be either painful (46°C) or non-painful (39°C).

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Background and aims Several pain conditions have been shown to reduce the discriminative abilities of external stimuli. The aim of this study was to investigate how cutaneous sensitization affects the tempo-spatial discrimination for both painful laser stimulation and mechanical stimulation. Methods Fifteen healthy subjects were presented with two different stimulation paradigms, a continuous line stimulation and a 2-point stimulation.

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Statins inhibit HMG-CoA reductase, the rate-limiting enzyme in the cholesterol biosynthesis pathway (CBP), and are used for the prevention of cardiovascular disease. The anti-inflammatory effects of statins may also provide therapeutic benefits and have led to their use in clinical trials for preeclampsia, a pregnancy-associated inflammatory condition, despite their current classification as category X (i.e.

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Neurons in the paraventricular nucleus of the hypothalamus (PVN) integrate peripheral signals and coordinate responses that maintain numerous homeostatic functions. An excess of glucocorticoids during fetal development results in long-lasting consequences tied to disrupted PVN development. The PVN contains a distinct neuronal population and a threefold greater vascular density than the surrounding brain regions that prepubertally is reduced in offspring exposed to excess glucocorticoids .

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The exteroceptive sensory system is responsible for sensing external stimuli in relation to time and space. The aim of this study was to investigate the tempo-spatial properties of the exteroceptive system using painful laser heat and nonpainful mechanical touch stimulation. Thirteen healthy subjects were stimulated on the volar forearm using 2 paradigms: a continuous stimulation along a line on the skin and a 2-point stimulation.

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