Personalized analysis of pain-weather associations: a pilot study

Background and purpose

It is a wellknown belief that weather can influence human health, including pain sensation. However, the current data are controversial, which might be due to the wide range of interindividual differences. The present study aimed to characterize the individual pain–weather associations during chronic pain by utilizing several data analytical methods.

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Methods

The study included 3-3 patients with (P1, P3, and P4) or without (P2, P5, P6) diabetes mellitus and signs of trigeminal neuralgia or low back pain. Subjective pain scores (0–10) and 12 weather parameters (terrestrial, geomagnetic, and solar) were recorded for one month repeated three times daily. Nonparametric Spearman’s correlation (Sp), multiple regression (Mx), and principal component (PCA) analyses were performed to evaluate associations between pain and meteorological factors obtained at the day of recorded pain value, 2 days before and 2 days after the recorded pain, and the changes in these parameters (5 × 12 parameters). Complex scores were calculated based on the results of these analyses.

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Results

While the temperature had the highest effects on the pain levels in most of the participants, huge interindividual dif­ferences in the degree and the direction of the associations between pain and weather parameters could be obtained. The analytic methods also revealed subjectspecific results, and the synthesis of different statistical methods as total scores provided a personalized map for each patient, which showed disparate patterns across the study participants. Thus, Participants 2 and 5 had higher scores for Mx compared to Sp; furthermore, certain factors showed opposite direction in their associations with the pain level depending on the type of analysis (Sp vs Mx). In contrast, P3 had a lower score for Mx compared to Sp, which might suggest a low level of weather sensitivity on the association between the different weather parameters in this subject. Furthermore, participants P4 and P6 had a very high level of weather sensitivity, while P1 had an opposite pattern. Regarding the time point-related effects on the pain level, most patients were sensitive to parameters obtained at the same day or two days before, except the P1 subject, who had the highest sensitivity to weather parameters detected two days after.

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Conclusion

The present study highlights the importance of integrating different data analysis approaches to elucidate the individual connections between pain and most of the weather parameters. In conclusion, complex personalized profiling should be considered for the characterization of pain–weather associations by applying different data analytical approaches, which may provide feedback to physicians and patients. 

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Neurobehavioral impairments in ciprofloxacin- treated osteoarthritic adult rats

Background and purpose

Ciprofloxacin (CIP) is a broad-spectrum antibiotic widely used in clinical practice to treat musculoskeletal infections. Fluoroquinolone-induced neurotoxic adverse events have been reported in a few case reports, all the preclinical studies on its neuropsychiatric side effects involved only healthy animals. This study firstly investigated the behavioral effects of CIP in an osteoarthritis rat model with joint destruction and pain, which can simulate inflammation-associated musculoskeletal pain. Furthermore, effects of CIP on regional brain-derived neurotrophic factor (BDNF) expression were examined given its major contributions to the neuromodulation and plasticity underlying behavior and cognition. 

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Methods

Fourteen days after induction of chronic osteoarthritis, animals were administered vehicle, 33 mg/kg or 100 mg/kg CIP for five days intraperitoneally. Motor activity, behavioral motivation, and psychomotor learning were examined in a reward-based behavioral test (Ambitus) on Day 4 and sensorimotor gating by the prepulse inhibition test on Day 5. Thereafter, the prolonged BDNF mRNA and protein expression levels were measured in the hippocampus and the prefrontal cortex. 

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Results

CIP dose-dependently reduced both locomotion and reward-motivated exploratory activity, accompanied with impaired learning ability. In contrast, there were no significant differences in startle reflex and sensory gating among treatment groups; however, CIP treatment reduced motor activity of the animals in this test, too. These alterations were associated with reduced BDNF mRNA and protein expression levels in the hippocampus but not the prefrontal cortex. 

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Conclusion

This study revealed the detrimental effects of CIP treatment on locomotor activity and motivation/learning ability during osteoarthritic condition, which might be due to, at least partially, deficient hippocampal BDNF expression and ensuing impairments in neural and synaptic plasticity.

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Synthesis, biochemical, pharmacological characterization and in silico profile modelling of highly potent opioid orvinol and thevinol derivatives

Morphine and its derivatives play inevitably important role in the μ-opioid receptor (MOR) targeted antinociception. A structure-activity relationship study is presented for novel and known orvinol and thevinol derivatives with varying 3-O, 6-O, 17-N and 20-alkyl substitutions starting from agonists, antagonists and partial agonists. In vitro competition binding experiments with [³H]DAMGO showed low subnanomolar affinity to MOR. Generally, 6-O-demethylation increased the affinity toward MOR and decreased the efficacy changing the pharmacological profile in some cases. In vivo tests in osteoarthritis inflammation model showed significant antiallodynic effects of thevinol derivatives while orvinol derivatives did not. The pharmacological character was modelled by computational docking to both active and inactive state models of MOR. Docking energy difference for the two states separates agonists and antagonists well while partial agonists overlapped with them. An interaction pattern of the ligands, involving the interacting receptor atoms, showed more efficient separation of the pharmacological profiles. In rats, thevinol derivatives showed antiallodynic effect in vivo. The orvinol derivatives, except for 6-O-desmethyl-dihydroetorfin (2c), did not show antiallodynic effect.

Preparation of bivalent agonists for targeting the mu opioid and cannabinoid receptors

In order to obtain novel pharmacological tools and to investigate a multitargeting analgesic strategy, the CB₁ and CB₂ cannabinoid receptor agonist JWH-018 was conjugated with the opiate analgesic oxycodone or with an enkephalin related tetrapeptide. The opioid and cannabinoid pharmacophores were coupled via spacers of different length and chemical structure. In vitro radioligand binding experiments confirmed that the resulting bivalent compounds bound both to the opioid and to the cannabinoid receptors with moderate to high affinity. The highest affinity bivalent derivatives 11 and 19 exhibited agonist properties in [³⁵S]GTPγS binding assays. These compounds activated MOR and CB (11 mainly CB₂, whereas 19 mainly CB₁) receptor-mediated signaling, as it was revealed by experiments using receptor specific antagonists. In rats both 11 and 19 exhibited antiallodynic effect similar to the parent drugs in 20 μg dose at spinal level. These results support the strategy of multitargeting G-protein coupled receptors to develop lead compounds with antinociceptive properties.

Somatostatin and cognitive function in neurodegenerative disorders

During the past 40 years, somatostatin (SST) has been a subject of intensive research. Apart from its substantial role in the neuroendocrine system, due to its dense localization in various areas in the brain, its functions as a neuromodulator have also been thoroughly investigated. Increasing evidence suggests that SST plays a crucial role in memory and cognition. Synthetic forms, biologically active peptide sequences, SST receptor agonists and SST depleting agents have been applied in animal models and in human studies of a number of neuropsychiatric disorders. The translation of experimental data into clinical use could provide novel therapies in neurodegenerative disorders involving cognitive dysfunctions. However in view of the controversial data reported concerning the different roles of the SST receptor subtypes, and the lack of SST analogs that are able to cross diffusion barriers and act selectively at these receptor subtypes, broader clinical use of SST analogs as cognitive enhancers is limited. This review covers the whole range of available experimental results relating to the behavioral effects of SST, and highlights the potential for further investigations.

[Pain sensitivity changes in schizophrenic patients and animal models--Part II]

Diminished pain sensitivity in schizophrenic patients has been reported for more than 50 years, however little is known about the substrate and the basic mechanisms underlying altered pain sensitivity in this disease, therefore, relevant animal models are of decisive importance in the study of psychiatric diseases. The authors report a review consisting of two parts focusing on pain sensitivity changes in patients and in different animal models which proved the eligibility as schizophrenia models and pain sensitivities have also been determined. The second part of this article analyzed the results regarding knock out mice as schizophrenia models. These data proved that several genes have significant role in the pathomechanism of schizophrenia; therefore deficiency in one gene does not produce animals showing all signs of this disease. As regards the pain sensitivity changes, only a few data are available with controversial results. Data originated from complex chronic animal models indicate that they might be more adequate methods for studying the mechanisms of schizophrenia including the pain-sensitivity changes.

[Pain sensitivity changes in schizophrenic patients and animal models. Part 1]

Diminished pain sensitivity in schizophrenic patients has been reported for more than 50 years, however little is known about the substrate and the basic mechanisms underlying altered pain sensitivity in this disease, therefore, relevant animal models are of decisive importance in the study of psychiatric diseases. The authors report a review consisting of two parts focusing on pain sensitivity changes in patients and in different animal models, which proved the eligibility as schizophrenia models and pain sensitivities have also been determined. The first session discusses the pain sensitivity changes in patients and chronic animal models induced by chronic drug treatments, social isolation or cerebral lesions. The results of human studies suggest that hypoalgesia in schizophrenia might be the endophenotype of this disease, however further studies are warranted to determine the clinical and biological correlation and the social and health consequences of hypoalgesia in schizophrenia. The animal data indicate that the pain sensitivity has changed in most models; however, there are significant controversies between the results, therefore, further studies are needed to find the ideal model.

[Combined use of pattern electroretinography and pattern visual evoked potentials in neuroophthalmological practice]

OBJECTIVE

To survey the role of pattern electroretinography (PERG) and pattern visual evoked potentials (VEPs) in the process of clinical evaluation of neuro-ophthalmological cases. The study is illustrated with the electrophysiological findings of 231 patients sent to our laboratory in 2005 because of the suspicion of damage in the optic pathway.

METHODS

The RETIport program of the ROLAND equipment (Wiesbaden-Germany) was used to record PERGs and VEPs. The recordings were done according to the recommendations of the International Society for Clinical Electrophysiology of Vision.

RESULTS

The combined application of PERG and VEP provided useful data on the retino-cortical conduction time and hence demyelinisation. The comparison of the N35/P50 and P50/N90 amplitudes of the PERG recordings greatly promoted the diagnostic procedure.

CONCLUSIONS

The combined application of PERG and VEP methods is recommended in the assessment of optic nerve function of neuro-ophthalmological patients.