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Biomedical subjects

Zaza Katsarava

Publications and source records attributed to Zaza Katsarava.

13 recordsLinked to original sources
PubMed2006

Pain related potentials by electrical stimulation of skin for detection of small-fiber neuropathy in HIV.

We compared the sensitivity of pain related evoked potentials (PREP), a novel electrophysiological technique, with standard nerve conduction (SNC) testing in the diagnosis of small fiber neuropathy in 47 patients with HIV infection and 31 age matched controls. SNC testing revealed a neuropathy in only 31%, whereas PREP was abnormal in 74% of symptomatic patients. This result hints that PREP is more sensitive in the detection of HIV-associated small fiber neuropathy than standard neurography.

Adult↗
PubMed2006

[Medication-overuse headache].

Headache associated with the chronic use of medications has become a significant problem in the management of headache. Typically, patients overusing analgesics suffer from tension headache, whereas those over-using triptans may experience daily migraine-type headaches or an increase in the frequency of migraine attacks. The treatment of choice in such cases is withdrawal of the medication followed as early as possible by medicinal prophylaxis of the primary headache.

Acute Disease↗
PubMed2006

Neurological complications after cadaveric and living donor liver transplantation.

Problems related to the central nervous system have a major impact on survival and quality of life. The aim of this retrospective study was to evaluate the incidence of neurological complications after liver transplantation (LT), including both cadaveric and living donor liver transplantation. Between April 2001 and March 2004 174 patients (120 cadaveric liver transplantations, 54 living donor transplantations) were admitted to our intensive care after liver transplantation. Of the transplanted patients 24.7% developed neurological complications. These patients' stay in the intensive care (14.2 +/- 17.2 days) was much longer than that of all admitted patients (8.4 +/- 10.5 days, p < 0.05). The most common neurological complications were encephalopathy (72.1%) and seizures (11.6 %). The incidence of neurological complications in living donor liver transplanted patients was significantly lower than in cadaveric transplantation patients (20.4% vs 26.7 %). The cold ischemia time in living donor transplanted patients was significantly shorter in comparison with cadaveric transplanted patients (215 +/- 119.3 vs. 383.7 +/- 214.7). The survival rate after liver transplantation of patients with neurological complications was lower than that of patients without, but not significantly different (79.1 % vs. 82.4%, p > 0.05). The incidence of neurological symptoms was found to be similar between the patients treated with cyclosporine (25%) and tacrolimus (23.8 %) in this study. In conclusion, there was a high incidence of neurological complications after LT, prolonging the patients' stay in intensive care significantly. The major neurological manifestation in our patients was encephalopathy followed by seizures. Living donor liver transplantation was associated with a significantly lower incidence of neurological complications compared with patients who had received a cadaveric graft. This might be due to the good quality of the organ and the much shorter cold ischemia time of the graft when the donor was alive.

Adult↗
PubMed2006

Improving patient selection for clinical acute stroke trials.

OBJECTIVE: To optimize patient inclusion criteria for clinical acute stroke trials. METHODS: We stratified probabilities of death and complete recovery based on two validated prognostic models using age and the National Institutes of Health Stroke Scale (NIH-SS) at admission. In an independent data set of 1,725 consecutively admitted patients with acute ischemic stroke, computer simulation with various inclusion thresholds was used to calculate the number and percentage of potential treatment responders, i.e. who had not died or spontaneously recovered. RESULTS: Using defined thresholds for recovery and mortality, inclusion and exclusion criteria could be designed to considerably decrease both trial time and study size compared to a fixed inclusion criterion based on the NIH-SS alone. Other thresholds may allow optimization of either trial time or study size. CONCLUSIONS: The resulting models provide a validated approach for an efficient study inclusion of potential treatment responders based on the Barthel Index 100 days after ischemic stroke. These techniques provide the opportunity for improved stroke trials in terms of enrollment speed, treatment effect size or both.

Adolescent↗
PubMed2006

Medication overuse headache.

Medication overuse headache (MOH) has developed into the third most common type of headache after tension-type headache and migraine. The prevalence of MOH is approximately 1% of the world's population and it shows an increasing trend as recent studies reveal a common involvement throughout the ages, even starting in childhood. All antiheadache drugs, such as triptans, analgesics, ergots and opioids, along with the common combination substances currently on the pharmacological market are capable of inducing MOH. New data on specific clinical features and mean critical monthly dosages and mean critical monthly intake frequencies are now available. The only effective treatment concept is consequent withdrawal therapy. Data of prospective studies on relapse rates and predictors of relapse after successful withdrawal therapy are presented.

Analgesics↗
PubMed2005

Behavioral conditioning with interferon beta-1a in humans.

Behavioral conditioning is one of the most impressive demonstrations of brain-immune system interaction. Numerous animal studies have demonstrated behavioral conditioned effects on immune functions, however, human studies are rare. We investigated whether it is possible to behaviorally condition the acute response to interferon (IFN)beta-1a. In a double-blind placebo-controlled study, 30 healthy subjects received a single injection of IFN(beta)-1a (6MIU of REBIF, Serono International) (unconditioned stimulus, UCS) together with a novel drink (conditioned stimulus, CS). Blood was drawn at baseline, 4, 8, and 24 h after drug administration. Within the first 8 h peripheral granulocytes significantly increased, while monocytes, lymphocytes, T-, B- and natural killer (NK) cell numbers were significantly reduced. In parallel, body temperature, heart rate, norepinephrine and interleukin (IL)-6 plasma levels were heightened within 8 h after injection. 8 days later, all previously IFN(beta)-treated subjects received a subcutaneous placebo (NaCl) injection, but only 15 subjects were re-exposed to the CS (experimental group), while a control group (N=15) drank water and an additional group of subjects (n=8) remained untreated (untreated group). Blood sampling was performed at baseline and at 4, 8, and 24 h. Re-exposition to the CS did not elicit conditioned responses in the experimental group. Moreover, no differences were observed between groups. These data provide negative findings regarding behavioral conditioning of cytokine effects in humans employing a one-trial learning paradigm.

Adult↗
PubMed2005

Patent foramen ovale: paradoxical connection to migraine and stroke.

PURPOSE OF REVIEW: In this article we aim to elucidate the relationship between patent foramen ovale, cryptogenic stroke and migraine. RECENT FINDINGS: Small observational and case-control studies indicate that patients with cryptogenic stroke have a higher incidence of patent foramen ovale. Prospective trials could not show a higher stroke recurrence risk with isolated patent foramen ovale. The combination of patent foramen ovale and atrial septal aneurysm might carry a higher recurrence risk. Secondary prevention with acetylsalicylic acid is as effective as oral anticoagulation, but carries a lower bleeding risk. Whether patent foramen ovale closure prevents recurrent strokes is under investigation. Case-control studies and retrospective analyses indicate comorbidity between patent foramen ovale and migraine, in particular migraine with aura. Recent retrospective studies indicate a reduction in migraine frequency after patent foramen ovale closure (intended for stroke prevention). These studies, however, have major methodological limitations. Therefore patent foramen ovale closure cannot be recommended for the prevention of migraine with aura. SUMMARY: At present routine percutaneous closure of isolated patent foramen ovale cannot be recommended for patients with cryptogenic stroke. Patent foramen ovale closure should not be used for the prevention of migraine.

Heart Septal Defects, Atrial↗
PubMed2004

Medication overuse headache.

PURPOSE OF REVIEW: The current literature on medication overuse headache will be reviewed with regard to clinical presentation, pathophysiology, therapy and prognosis in the light of the new headache classification. RECENT FINDINGS: Medication overuse headache is a widely unrecognized medical condition, which according to recent epidemiological studies has evolved to the third most frequent form of headache after tension-type headache and migraine. The first classification of headache disorders from 1988 defined medication overuse headache (formerly called 'drug-induced headache') on the bases of drugs that were available in the 1980s. For the most important anti-headache drugs, including triptans, new data on specific clinical features and more important mean critical monthly dosages and mean critical monthly intake frequencies are now available. Furthermore, recent prospectively conducted studies have revealed rates and predictors of relapse after successful withdrawal. SUMMARY: The newly available data on medication overuse headache may provide the basis for future consensus guidelines for the management of this condition.

Analgesics↗
PubMed2003

Symptomatic migraine and sensitization of trigeminal nociception associated with contralateral pontine cavernoma.

A 38-year-old woman is described with symptomatic strictly right-sided migraine associated with a pontine cavernoma affecting the contralateral (left) nucleus raphe magnus. A persistent facilitation of the right-sided trigeminal nociception was detected interictally using the 'nociception specific' blink reflex, which was more pronounced during the acute attack. This case shows for the first time, an impairment of the anti-nociceptive brainstem nuclei and the facilitation of the trigeminal nociception in the same subject, thus providing further evidence for the key role of the brainstem raphe nuclei in the pathophysiology of migraine.

Adult↗
PubMed2001

Is the R3 component of the human blink reflex nociceptive in origin?

The R3 component of the blink reflex can reproducibly be evoked by noxious stimulation but can probably also be elicited by innocuous stimuli. This study was conducted to investigate the contribution of nociceptive A delta and C fibers to the generation of the electrically evoked R3 blink reflex. Electrical thresholds for detection, pain and all blink reflex components were determined and the modulatory effects of local anesthesia were investigated. The electrical R3 threshold of 4.6 +/- 0.5 mA (mean +/- SE) corresponded to 2.9 times the detection threshold and to 0.35 times the pain threshold. The R3 threshold was significantly below the pain threshold. Under local anesthesia of the supraorbital skin with a complete loss of warm and cold sensation, a loss of pinprick sensation, but a normal detection of tactile stimuli, the electrical pain threshold increased, all other thresholds remained unchanged. Under local anesthesia none of the reflex components were significantly reduced. Cutaneous A beta fibers and nociceptive A delta fibers, but not unmyelinated C fibers, contribute to the generation of the electrically evoked R3 component. According to the recruitment order in peripheral sensory nerves the electrical threshold of the R3 is mainly determined by activation of A beta fibers. Thus, it can not be assumed that the electrically evoked R3 is an adequate model to investigate nociceptive processing.

Adult↗
PubMedDate not supplied

A novel method of eliciting pain-related potentials by transcutaneous electrical stimulation.

BACKGROUND: Electrophysiological techniques such as laser and contact heat evoked pain-related potentials are very useful for studying trigeminal and somatic pain transmission in humans. These methods are, however, partly invasive, expensive, and therefore not available for broad clinical use. We recently proposed a novel technique of noninvasive transcutaneous electrical stimulation. OBJECTIVE: To elicit pain-related evoked potentials (PREP) by using a concentric planar electrode and demonstrate their nociceptive specificity. METHODS: We registered PREP following stimulation of the forehead and hand in 14 healthy volunteers. Latencies, peak-to-peak amplitudes, and conduction velocities of nociceptive fibers have been estimated. Effects of temporal and spatial summation and of cutaneous anesthesia were evaluated. RESULTS: Stimulation with the concentric planar electrode produced pinprick-like painful sensation. Cutaneous anesthesia led to abolishment of PREP responses. Estimated mean conduction velocity was 11.61 +/- 5.12 m/s, which corresponded well with conduction via A-delta fibers. Spatial as well as temporal summation resulted in a parallel increase of perceived pain intensity and PREP amplitudes. CONCLUSION: The technique is noninvasive, affordable, and easy to perform and allows quantitative assessment of human nociceptive pathways.

Adult↗