Does risperidone improve verbal working memory in treatment-resistant schizophrenia?

OBJECTIVE: Treatment efficacy in schizophrenia is typically defined in terms of symptom reduction. However, new antipsychotic medications could potentially have an impact on aspects of disability, such as neurocognitive deficits. The authors evaluated the effects of risperidone on verbal working memory, a memory component of theoretical interest because of its link to prefrontal activity and of practical interest because of its link to psychosocial rehabilitation. METHOD: Verbal working memory of 59 treatment-resistant schizophrenic patients was assessed as part of a randomized, double-blind comparison of treatment with risperidone and haloperidol. Verbal working memory was measured under both distracting and nondistracting conditions at baseline and after 4 weeks of both fixed- and flexible-dose pharmacotherapy. RESULTS: Risperidone treatment had a greater beneficial effect on verbal working memory than haloperidol treatment across testing conditions (with and without distraction) and study phases (fixed and flexible dose). The treatment effect remained significant after the effects of benztropine cotreatment, change in psychotic symptoms, and change in negative symptoms were controlled. Neither benztropine status nor symptom changes were significantly related to memory performance. CONCLUSIONS: Treatment with risperidone appears to exert a more favorable effect on verbal working memory than treatment with a conventional neuroleptic. The beneficial effect appears to be due, at least partially, to a direct effect of the drug, possibly through antagonism of the 5-HT2A receptor. Results from this study suggest that pharmacotherapeutic efficacy in schizophrenia treatment could be broadened to include impact on neurocognitive abilities.     

The offensive subtype of Taijin-kyofu-sho in New York City: the phenomenology and treatment of a social anxiety disorder

The action of two isomers of thioctic acid was tested in-vitro by using the hippocampal slice technique. Various models to induce hyperexcitability of the pyramidal cells were used in order to characterize the drug action. Increases of the applied glucose above the usual concentration of 10 mM lead to a concentration dependent enhancement of the population spike amplitude peaking in a 200% increase at a concentration of 30 mM, whereas lower glucose concentrations result in diminished amplitudes. Both isomers of thioctic acid antagonize the hyperexcitability to a different degree with IC50's of 43 microM and 281 microM for the l- and the d-isomer, respectively. As thioctic acid passes the blood brain barrier very well, these results might suggest a protective action of thioctic acid on the brain during hyperglycemic episodes in diabetic patients. Regarding the mechanism of action, thioctic acid firstly reverses the effect of 6 mM calcium in the superfusion fluid and secondly reverses the effect of apamin, an highly selective neurotoxin of bee venom, acting as the most specific blocker of the small conductance calcium dependent potassium channel. As this channel has been described to occur also in liver, an interaction with it may underly the central and peripheral action of thioctic acid. Together with the already available evidence, these experiments support the hypothesis that thioctic acid can be regarded as a stereoselective neuroprotective agent preventing cells from being damaged by excess of calcium or hyperexcitability induced by blockade of a specific class of potassium channels.     

Evanescent wave fibre optic sensor for detection of L. donovani specific antibodies in sera of kala azar patients

An easy-to-use technique for detection of antibodies specific for the parasite L. donovani in human serum sample has been developed. The method is based on an evanescent wave generated from a tapered configuration of decladded optical fibre and does not require any volumetric measurement. Tapered fibres are immobilized with the purified cell surface protein of L. donovani by covalent bonding. Treated fibres are incubated with the patient serum for 10 min followed by incubation with goat anti human IgG tagged FITC. Fluorescent intensity from the fibre has been shown to be proportional to L. donovani specific antibodies present in the test sera. Direct readings can be obtained after signal enhancement through a photomultiplier tube within 5 min. The system, when tested on 12 positive sera, did not show any false negative result. Also, no false positive result was obtained with serum samples of patients infected with leprosy, tuberculosis, typhoid and malaria, showing the specificity of the sensor and efficacy of the technique.     

Functional and morphometric evaluation of offspring kidney after intrauterine undernutrition

Pregnant rats were subjected to 50% food restriction during the first or the second half of pregnancy, or throughout pregnancy. The effects of intrauterine food restriction, on kidney function and morphometry were studied in newborn and adult (3 months) offspring. No differences in glomerular diameter were observed in newborn restricted rats compared with controls. The number of glomeruli was significantly lower both in newborn and 3-month-old restricted rats. However, glomerular diameter was increased in 3-month-old rats, which suggests that hypertrophic stimuli were present. The medulla/cortex ratio increased in adult rats submitted to food restriction during pregnancy, a finding that agrees with the preserved sodium and acid excretion, and the normal osmolar and free water clearance observed in these groups. These results show that the reduction in glomerular number is still present 3 months after birth in the progeny of mothers submitted to severe food restriction during pregnancy, suggesting impairment of glomerulogenesis even after birth. Intra utero undernutrition can be regarded as an experimental model of glomerular hypertrophy.     

Clinical parameters associated with falls in an elderly population

Cognitive function was investigated in a random sample of subjects on the general practitioners' registry of hypertensive patients in an inner city area and matched with normotensive controls. The response rate was 66% giving 90 matched pairs, average age 63 yrs, with 47% men. There was no difference in educational background or measures of reading ability between the two groups. Cognitive function tests showed a consistent trend of poorer performance in hypertensives, with significant differences in Verbal Learning (immediate recall and retention). Age was inversely related to cognitive function, but no additional deterioration with increasing age was shown in hypertensives.