Cognitive impairments of alcoholic cirrhotic patients: correlation with endogenous benzodiazepine receptor ligands and increased affinity of platelet receptors

Effect of trataka on cognitive functions in the elderly

BACKGROUND

Trataka, a type of yoga practice is considered to improve cognitive functions. The aim of this study was to test the effect of trataka on cognitive functions of the elderly.

MATERIALS AND METHODS

Elderly subjects were recruited based on inclusion and exclusion criteria (n = 60) and randomly divided using randomized block design into two groups: Trataka and wait list control group. Trataka (a visual cleansing technique) was given for a period of 1 month (26 days). The subjects in both groups were assessed on day 1 (pre- and postintervention in trataka group and after quiet sitting in control group) and on day 30 on Digit Span Test, Six Letter Cancellation Test (SLCT), and Trail Making Test-B (TMT-B).

RESULTS

Friedman's test and Wilcoxon signed-rank test showed that at the 2(nd) follow-up there was significant improvement in digit span scores (z = -3.35, P < 0.01) in the trataka group. SLCT scores (t = 5.08, P < 0.01) and TMT-B scores (t = -4.26, P < 0.01) improved immediately after the practice of trataka (when baseline compared to first follow-up). At 1 month follow-up, trataka group showed significantly better performance in the SLCT test compared to baseline (t = -3.93, P < 0.01) and TMT-B scores (t = 7.09, P < 0.01). Repeated measure analysis of variance (RM ANOVA) results also reiterated that there was significant interaction effect at the end of 1 month of trataka intervention as compared to control group on TMT-B and SLCT scores.

CONCLUSIONS

The results of this study establish that Trataka can be used as a technique to enhance cognition in the elderly.

Normative data for the letter-cancellation task in school children

Aims:

To establish the norms for the letter-cancellation task—a psychomotor performance task.

Materials and Methods:

Eight hundred nineteen school students were selected in the present study in an age range between nine and 16 years (M = 12.14; SD = 1.78 years). Subjects were assessed once for the cancellation task.

Results:

Both age and sex influenced performance on the SLCT; therefore, correction scores were obtained on the basis of these factors.

Conclusions:

The availability of Indian normative data for the SLCT will allow wider application of this test in clinical practice.

Benzodiazepine-sensitive GABA(A) receptors in the commissural subnucleus of the NTS are involved in the carotid chemoreceptor reflex in rats

We studied the role of benzodiazepine (BDZ) receptors in the commissural subnucleus of the nucleus tractus solitarius (commNTS) in chemoreceptor reflex in urethane-anesthetized, pancronium-immobilized, artificially ventilated and bilaterally vagotomized rats. A BDZ agonist, diazepam (1-4 micromol/kg), administered intravenously reduced resting phrenic nerve activity (PNA) and blood pressure (BP). Stimulation of carotid chemoreceptors induced an increase in PNA and an increase in BP. Diazepam inhibited this chemoreceptor reflex. The effects of intravenous injection of diazepam (4 micromol/kg) on the chemoreceptor reflex were antagonized by microinjection of the BDZ antagonist flumazenil (100 pmol) into the commNTS. Microinjection of flumazenil (100 pmol) alone had no effect on the basal PNA and BP, and the chemoreceptor reflex. These results suggest that BDZ receptors are present in the carotid chemoreceptor reflex pathway in the commNTS and potentiate GABA(A) transmission.

Benzodiazepine receptor antagonists for hepatic encephalopathy

BACKGROUND

Hepatic encephalopathy may be associated with accumulation of substances that bind to a receptor-complex in the brain resulting in neural inhibition. Benzodiazepine receptor antagonists may have a beneficial effect on patients with hepatic encephalopathy.

OBJECTIVES

To evaluate the beneficial and harmful effects of benzodiazepine receptor antagonists for patients with hepatic encephalopathy.

SEARCH STRATEGY

Eligible trials were identified through The Cochrane Hepato-Biliary Group Controlled Trials Register, The Cochrane Controlled Trials Register on The Cochrane Library, MEDLINE and EMBASE (last search: January 2004), reference lists of relevant articles, authors of trials, and pharmaceutical companies.

SELECTION CRITERIA

Randomised trials comparing any benzodiazepine receptor antagonist versus placebo or no intervention for hepatic encephalopathy.

DATA COLLECTION AND ANALYSIS

Two reviewers independently included trials and extracted data. Binary outcomes are reported as risk difference (RD) with 95% confidence intervals (CI) based on a random effects model. Statistical heterogeneity was explored by a chi-squared test with significance set at P < 0.1. The inconsistency across trials was assessed by I(2). Potential sources of heterogeneity were explored through subgroup analyses.

MAIN RESULTS

Thirteen randomised trials with 805 patients were included. Eight trials used a crossover design. All trials were double-blind and assessed flumazenil versus placebo. Data on all outcomes could not be extracted from all trials. The included patients had a favourable prognosis (361/390 [93%] survived in the flumazenil group versus 345/376 [92%] in the placebo group). Flumazenil had a significant beneficial effect on improvement of hepatic encephalopathy at the end of treatment (RD 0.28; 95% CI 0.20 to 0.37, eight trials). Flumazenil had no significant effect on recovery (RD 0.13; 95% CI -0.09 to 0.36, two trials) or mortality RD 0.01; 95% CI -0.05 to 0.07, 10 trials). Flumazenil may be associated with adverse events, but trial results were heterogeneous.

REVIEWERS' CONCLUSIONS

Flumazenil had a significant beneficial effect on short-term improvement of hepatic encephalopathy in patients with cirrhosis and a highly favourable prognosis. Flumazenil had no significant effect on recovery or survival. Considering the fluctuating nature of hepatic encephalopathy, future trials should use a parallel design and assess if treatment with flumazenil leads to a sustained improvement or increased recovery and survival. Until this has been demonstrated, flumazenil may be considered for patients with chronic liver disease and hepatic encephalopathy, but cannot be recommended for routine clinical use.

Neurocognitive impairment associated with alcohol use disorders: implications for treatment

Between 50% and 80% of individuals with alcohol use disorders experience mild to severe neurocognitive impairment. There is a strong clinical rationale that neurocognitive impairment is an important source of individual difference affecting many aspects of addiction treatment, but empirical tests of the direct influence of impairment on treatment outcome have yielded weak and inconsistent results. The authors address the schism between applied-theoretical perspectives and research evidence by suggesting alternative conceptual models of the relationship between neurocognitive impairment and addiction treatment outcome. Methods to promote neurocognitive recovery and ways in which addiction treatments may be modified to improve psychosocial adaptation are suggested. Specific suggestions for future research that may help clarify the complex relations between neurocognitive impairment and addiction treatment are outlined.

Benzodiazepine receptor antagonists for acute and chronic hepatic encephalopathy

BACKGROUND

The pathogenesis of hepatic encephalopathy is unknown. It has been suggested that liver failure leads to the accumulation of substances that bind to a receptor-complex in the brain resulting in neural inhibition which may progress to coma. Several trials have assessed benzodiazepine receptor antagonists for hepatic encephalopathy, but the results are conflicting.

OBJECTIVES

To evaluate the efficacy and safety of benzodiazepine receptor antagonists for patients with acute or chronic hepatic encephalopathy.

SEARCH STRATEGY

Eligible trials were identified through The Cochrane Hepato-Biliary Group Controlled Trials Register, The Cochrane Controlled Trials Register, MEDLINE, EMBASE, reference lists of relevant articles, authors of trials, and the pharmaceutical company known to produce benzodiazepine receptor antagonists.

SELECTION CRITERIA

Randomised trials comparing any benzodiazepine receptor antagonist versus placebo or no intervention for hepatic encephalopathy were included, regardless of language or publication status.

DATA COLLECTION AND ANALYSIS

Trial inclusion and data extraction were made independently by two contributors. Depending on the presence or absence of significant heterogeneity (P<0.1) a random or fixed effect model was used. Potential causes for heterogeneity were explored by sensitivity analyses.

MAIN RESULTS

Twelve randomised trials with 765 patients were included. Eight trials used a crossover design. All trials were double-blind and assessed flumazenil versus placebo. Data on all outcomes could not be extracted from all trials. The included patients had a favourable prognosis (341/370 (92%) survived in the flumazenil group versus 325/356 (91%) in the placebo group). Flumazenil had no significant effect on full recovery (two trials), survival (nine trials), or on the occurrence of adverse events (five trials). However, flumazenil was associated with a significant effect on improvement of hepatic encephalopathy compared to placebo at the end of treatment (103/346 (30%) versus 23/332 (7 %), risk difference 0.23, 95% confidence interval 0.18 to 0.28, five trials).

REVIEWER'S CONCLUSIONS

Flumazenil had no significant effect on recovery or survival from hepatic encephalopathy. However, flumazenil had a significant effect on short-term improvement of hepatic encephalopathy in some patients with chronic liver disease and a highly favourable prognosis. Considering the fluctuating nature of hepatic encephalopathy, future trials should use a parallel design and assess if treatment with flumazenil leads to a sustained improvement or increased recovery and survival. Until this has been demonstrated, flumazenil may be considered for patients with chronic liver disease and hepatic encephalopathy, but cannot be recommended for routine clinical use.

The influence of alcoholism and cirrhosis on benzodiazepine receptor function

In a previous study we reported that the affinity of the platelet benzodiazepine receptor was greater in alcoholic cirrhotic patients compared with normal controls and that there were detectable ligands for the neuronal benzodiazepine receptor in plasma from both alcoholic and nonalcoholic cirrhotic patients. The aim of the present study was to assess the separate contributions of alcoholism and cirrhosis to the presence of ligands in plasma for the neuronal and peripheral benzodiazepine receptors and to changes in peripheral benzodiazepine receptor binding in platelets. These parameters were measured in 10 alcoholic cirrhotics, 9 nonalcoholic cirrhotics, 7 alcoholics with a normal liver function, and 15 nonalcoholic subjects and normal liver function. Both groups of alcoholics had been abstinent for several months and the nonalcoholic groups had abstained for 24 h before the study. The concentration of ligands for the peripheral benzodiazepine receptor were significantly higher in both cirrhotic groups compared with the other two groups, suggesting that cirrhosis was responsible for this accumulation. Furthermore, the cirrhotic patients with detectable concentrations of these ligands had significantly poorer episodic memory than those without ligands. However, the presence of ligands for the peripheral benzodiazepine receptor did not correlate with the change in receptor affinity, which was increased in the alcoholic cirrhotic group compared with all other groups. Neither cirrhosis nor alcoholism altered the peripheral benzodiazepine receptor number. The cirrhotic patients with detectable ligands for the neuronal benzodiazepine receptor showed psychomotor slowing and executive dysfunction. The results suggest that the ligands for the peripheral benzodiazepine receptor may contribute to some of the cognitive deficits seen in hepatic encephalopathy, but are not responsible for the receptor affinity change seen in the alcoholic cirrhotics. This affinity change is not solely due to the effects of alcohol and could possibly serve as a marker for those at risk for developing alcoholic cirrhosis.

Benzodiazepine-like substances and hepatic encephalopathy : implications for treatment

Hepatic encephalopathy is a neuropsychiatric syndrome that can complicate acute and chronic liver disease. Recent research has focused on the role benzodiazepine-like substances play in the pathogenesis of this disorder. It has been proposed that potentiation of the action of the neuroinhibitory transmitter γr-aminobutyric acid (GABA) through the binding of endogenous benzodiazepine agonists to the benzodiazepine receptor binding site accounts for the clinical and biochemical features of this condition.Increased levels of endogenous benzodiazepine-like substances have been noted in animal models of hepatic encephalopathy. In human studies, levels of these substances of up to 10 times those found in the body fluids of nonencephalopathic controls have been reported. The existence of such markedly elevated levels cannot be satisfactorily explained with reference to possible pharmaceutical or dietary origins.Further support for the role of benzodiazepines in the mediation of hepatic encephalopathy comes from the therapeutic effect reported after administration of the benzodiazepine receptor antagonist flumazenil. Improvements in the severity of hepatic encephalopathy have been documented in rats with fulminant hepatic failure given flumazenil, although results have been inconsistent according to the dose of flumazenil used and the procedure employed to induce the encephalopathy. Transient, but distinct, improvements in the grade of hepatic encephalopathy have also been documented in several human studies. In a placebo-controlled study involving patients with mild hepatic encephalopathy, a low dose of flumazenil (0.2 mg/kg) resulted in a significant improvement in reaction time.Research now needs to identify whether the beneficial effect of flumazenil is due to its antagonistic or inverse agonistic properties, and also to clarify the mechanisms by which the differential response to the drug in animal models of fulminant hepatic failure is mediated.