[Evaluation of two immunocromatographic tests for the detection of antibodies against SARS-CoV-2]

OBJECTIVE

Serological tests have been a valuable tool during the SARS-CoV-2 pandemic, supporting molecular methods for detection, and monitoring the immune response, caused by vaccination or by natural infection. Within all these techniques, rapid tests are interesting due to their ease of use, rapid response and low cost.

METHODS

Two different immunological techniques were evaluated: Realy Tech and Mikrogen Diagnostik recomLine SARS-CoV-2 IgG. SARS-CoV-2 IgG II Quant antibody test and SARS-CoV-IgG assay, both from Abbott Diagnostics, were used as reference techniques.

RESULTS

Mikrogen Diagnostik recomLine SARS-CoV-2 IgG shows the best results (S=0.985; E=0.839). Three techniques offered good positive predictive values, but Realy Tech and Healgen negative predictive values left to be desired.

CONCLUSIONS

Mikrogen Diagnostik recomLine SARS-CoV-2 IgG showed good results in the detection of antibodies against SARS-CoV-2 and could be used as an alternative to automated techniques.

Impact of early use of long-acting injectable antipsychotics on functional outcome in first episode psychosis: a 3-year longitudinal study

OBJECTIVES

To describe, in a naturalistic setting, the impact of the early use of LAI-AP on functional outcomes of early psychosis patients as compared to oral antipsychotics (OAP).

METHODS

Longitudinal prospective 3-year naturalistic study of all consecutive admissions (n = 416) to two Early intervention services (EIS) for psychosis comparing baseline characteristics and the evolution of global functioning, occupation (work and studies), and living arrangements autonomy according to the route of administration of the antipsychotic medication. The cohort was divided into four groups: LAI-AP first (started on LAI-AP and later received OAP), OAP first, LAI-AP only, and OAP only.

RESULTS

Global assessment of functioning (GAF) improved in all groups, but our mixed-effect model did not show any significant association between the route of administration and the GAF outcome. The LAI-AP only group was significantly less likely to have extreme residential instability at 3 years than the other groups despite its highest proportion of homeless youth and their poor prognostic factors at baseline.

CONCLUSIONS

Our naturalistic study suggests a significant protective effect of LAI-AP on extreme residential instability for the most vulnerable patients, but no impact of the first AP administration route on other functional outcomes was observed at 3 years of follow-up. Key pointsLong-acting injectable antipsychotics seem promising to avoid extreme residential instability in early psychosis.Global assessment of functioning (GAF) improved in all groups.There was no significant association between the first route of administration and global functionning.

Long-acting antipsychotic medication as first-line treatment of first-episode psychosis with comorbid substance use disorder

AIM

Substance use disorder (SUD) is highly prevalent among patients with first-episode psychosis (FEP) and associated with poor adherence and worst treatment outcomes. Although relapses are frequent in FEP, current literature on long-acting injectable antipsychotics (LAI-AP) use in FEP is scarce and studies often exclude patients with SUD.

OBJECTIVES

To determine the impact of LAI-AP as first-line treatment on psychotic relapses or rehospitalizations in FEP patients with comorbid SUD (FEP-SUD).

METHODS

This is a naturalistic, longitudinal, 3-year prospective and retrospective study on 237 FEP-SUD admitted in two EIS in Montreal, between 2005 and 2012. The patients were divided on the basis of first-line medication introduced, either oral antipsychotics (OAP, n = 206) or LAI-AP (n = 31). Baseline characteristics were compared using χ² test and analysis of variance, and Kaplan-Meier survival analysis was performed on relapse and rehospitalization.

RESULTS

Compared to the OAP group, patients in the LAI-AP group presented worse prognostic factors (eg, history of homelessness). Despite this, the LAI-AP group presented a lower relapse rate (67.7% vs 76.7%), higher relapse-free survival time (694 vs 447 days, P = 0.008 in Kaplan-Meier analysis), and trends for reduced rehospitalization rates (48.4% vs 57.3%) and hospitalization-free survival time (813 vs 619 days, P = 0.065 Kaplan-Meier analysis). Of those receiving OAP as first-line, 41.3% were eventually switched to LAI-AP and displayed worst outcome in relapse and rehospitalization.

CONCLUSION

LAI-AP should be strongly considered as first-line treatment of FEP-SUD patients since this pharmacological option reduces the risk of relapse and rehospitalization even in the individuals with poor prognostic factors.

Update in Infectious Diseases 2019

The IX Course of Antimicrobials and Infectious Diseases update included a review of the main issues in clinical microbiology, epidemiology and clinical aspects for a current approach of infectious pathology. The present introduction summarizes about the most important meetings related to infectious diseases during 2018 (ECCMID, IAS, ASM and ID Week). In addition, the course provides a practical information to focus on nosocomial infection models, with immunosuppressed patients or complex multidrug-resistant pathogens. The closing lecture of this year reviewed the infection during donation process.

Three-Year Naturalistic Study On Early Use Of Long-Acting Injectable Antipsychotics In First Episode Psychosis

ABSTRACT

Poor adherence to antipsychotics, which affects outcome, is frequent in first episode psychosis (FEP). Most randomized studies demonstrate no superiority of long-acting injectable antipsychotics (LAI-AP) over oral antipsychotics (OAP). However, participants in these studies represent a minority of patients who may benefit from LAI-AP. Mirror and naturalistic studies generally demonstrate efficacy of LAI-AP on more representative samples, but studies on FEP are scarce.

AIM

To describe LAI-AP's utilization and impact on FEP outcome in a naturalistic setting.

METHODS

A 3-year longitudinal prospective and retrospective descriptive study of all consecutive admissions from two Early Intervention Services for psychosis (EIS) in Montréal, Canada, compared the characteristics and evolution of patients who received LAI-AP for at least 12 months to those who received OAP only.

RESULTS

From 375 FEP patients included, 26,7% received LAI-AP during their follow-up. They were more likely to have poor prognostic factors (male gender, lower premorbid functioning, homelessness, substance use disorder and schizophrenia spectrum diagnoses). Despite a more severe illness and lower functioning in the LAI-AP group, at admission and study endpoint, clinical and functional improvements were observed.

CONCLUSION

Early prescription of LAI-AP seems beneficial in FEP with poor prognostic factors.

Brainstem leukoaraiosis independently predicts poor outcome after ischemic stroke

BACKGROUND AND PURPOSE

Increased supratentorial white matter hyperintensities volume (S-WMHV) has been reported to be a predictor of worse outcome in patients with acute ischemic stroke (AIS). However, few studies have focused on less common locations, such as brainstem white matter hyperintensities (B-WMH), and their relationship to S-WMHV. This study aimed to examine whether B-WMH affect clinical outcome after AIS or transient ischemic attack (TIA).

METHODS

Based on magnetic resonance imaging evidence, B-WMH were evaluated in 313 prospectively identified patients with AIS/TIA and registered as absent or present. Standardized S-WMHV was quantified using a validated volumetric image analysis and natural log-transformed (Log_S-WMHV). Poor outcome was defined as a modified Rankin Scale score of 3-6 at 3 months after the index event.

RESULTS

Brainstem white matter hyperintensities were detected in 57 (18.2%) patients. In unadjusted analyses for outcome, the presence of B-WMH was associated with worse outcome, compared with patients without B-WMH (P = 0.034). In multivariate analysis controlling for age, atrial fibrillation, stroke severity, reperfusion therapies and Log_S-WMHV, only B-WMH [odds ratio (OR), 2.46; P = 0.021] and stroke severity (OR, 1.23; P < 0.001) remained independently associated with unfavourable 90-day modified Rankin Scale score. Patients with B-WMH were older (OR, 1.06; P < 0.001) and tended to have more hyperlipidaemia (OR, 2.21; P = 0.023) and peripheral arterial disease (OR, 2.57; P = 0.031).

CONCLUSIONS

Brainstem white matter hyperintensities are an independent predictor of poor outcome after AIS/TIA and this relationship persists after adjustment for important prognostic factors. Our results also show that leukoaraiosis in this location identifies patients with a specific risk factor profile, suggesting differences in the underlying pathogenesis.

Immigrants' outcome after a first-episode psychosis

AIM

Immigration is a risk factor for psychosis emergence, and previous studies show that immigrants are less likely to engage in treatment for psychosis. However, the literature on outcome is scant and heterogeneous. This study was designed to compare first-generation (FGI) and second-generation immigrants (SGI) to non-immigrants' symptomatic and functional outcomes 2 years after a first-episode psychosis (FEP).

METHODS

A 2-year prospective longitudinal study of 223 FEP patients between 18 and 30 years took place in two early intervention services (EIS) in Montreal, Canada.

RESULTS

Forty-two per cent of the sample were immigrants (FGI (n = 56), SGI (n = 38)). Compared with non-immigrants, immigrants had similar symptomatic and functioning profiles at baseline, 1 and 2 years, except that fewer SGI had a history of homelessness and more were living with their families. FGI were less likely to have a substance use disorder but more likely to pursue their studies and to present depressive symptoms.

CONCLUSIONS

Even if immigrants are known to be at greater risk of developing psychosis, probably secondary to stress related to immigration, their symptomatic and functional outcomes, once engaged in EIS treatment, are similar to or sometimes better than non-immigrants' outcomes. Because immigrants tend to be less engaged in their follow-up, understanding why they disengage from treatment is crucial to develop better therapeutic approaches to better engage them as EIS treatment can improve their outcomes effectively.

Noonan syndrome in diverse populations

Noonan syndrome (NS) is a common genetic syndrome associated with gain of function variants in genes in the Ras/MAPK pathway. The phenotype of NS has been well characterized in populations of European descent with less attention given to other groups. In this study, individuals from diverse populations with NS were evaluated clinically and by facial analysis technology. Clinical data and images from 125 individuals with NS were obtained from 20 countries with an average age of 8 years and female composition of 46%. Individuals were grouped into categories of African descent (African), Asian, Latin American, and additional/other. Across these different population groups, NS was phenotypically similar with only 2 of 21 clinical elements showing a statistically significant difference. The most common clinical characteristics found in all population groups included widely spaced eyes and low-set ears in 80% or greater of participants, short stature in more than 70%, and pulmonary stenosis in roughly half of study individuals. Using facial analysis technology, we compared 161 Caucasian, African, Asian, and Latin American individuals with NS with 161 gender and age matched controls and found that sensitivity was equal to or greater than 94% for all groups, and specificity was equal to or greater than 90%. In summary, we present consistent clinical findings from global populations with NS and additionally demonstrate how facial analysis technology can support clinicians in making accurate NS diagnoses. This work will assist in earlier detection and in increasing recognition of NS throughout the world.

Perfusion SPECT, SISCOM and PET (18)F-FDG in the assessment of drug- refractory epilepsy patients candidates for epilepsy surgery

AIMS

Brain perfusion SPECT (ictal-interictal), SPECT images and subtraction ictal SPECT coregistered to MRI (SISCOM) and (18)F-FDG-PET (interictal), play an important role in the pre-surgical diagnosis of patients with medically refractory epilepsy. This study aimed to establish: the reproducibility of visual ictal-interictal SPECT and SISCOM analysis altogether with the capacity of SPECT, SISCOM and PET to determine the epileptogenic zone.

MATERIAL AND METHODS

(99m)Tc-HMPAO SPECT ictal-interictal and SISCOM (Analyze 7.0) were performed on 47 refractory epilepsy patients (24 F, 19-60 yrs). In 13 patients, SISCOM was also performed using a new program (Focus DET). Ictal-interictal SPECT and SISCOM images were analysed independently by two nuclear medicine physicians (observer 1 and 2). Kappa concordance coefficient was used to evaluate the reproducibility. In sixteen patients, SPECT, SISCOM and PET findings were compared with the resected area during the surgery, and surgical outcome using Engel scale or with the stereo EEG-(SEEG).

RESULTS

The ictal-interictal SPECT interobserver agreement was 91%, Kappa index 0.86, SISCOM (Analyze 7.0) interobserver agreement percentage was 82%, Kappa index 0.80, Analyze 7.0 showed a higher inconclusive results than visual SPECT analysis. SISCOM FocusDET interobserver agreement was 92%, Kappa index 0.87, with lower inconclusive results than Analyze 7.0. SPECT, SISCOM and PET combined findings identified 87% seizure onset zone: 79% temporal, 26% parieto-temporal and 7% frontal.

CONCLUSIONS

Ictal-interictal SPECT and SISCOM showed a high reproducibility in this sample of patients with drug-refractory epilepsy. SPECT,SISCOM and PET combined findings improved detection of epileptogenic zone in comparison with the individual assessment.

Simple fMRI postprocessing suffices for normal clinical practice

BACKGROUND AND PURPOSE

Whereas fMRI postprocessing tools used in research are accurate but unwieldy, those used for clinical practice are user-friendly but are less accurate. We aimed to determine whether commercial software for fMRI postprocessing is accurate enough for clinical practice.

METHODS

Ten volunteers underwent fMRI while performing motor and language tasks (hand, foot, and orolingual movements; verbal fluency; semantic judgment; and oral comprehension). We compared visual concordance, image quality (noise), voxel size, and radiologist preference for the activation maps obtained by using Neuro3D software (provided with our MR imaging scanner) and by using the SPM program commonly used in research.

RESULTS

Maps obtained with the 2 methods were classified as "partially overlapping" for 70% for motor and 72% for language paradigm experiments and as "overlapping" in 30% of motor and in 15% of language paradigm experiments.

CONCLUSIONS

fMRI is a helpful and robust tool in clinical practice for planning neurosurgery. Widely available commercial fMRI software can provide reliable information for therapeutic management, so sophisticated, less widely available software is unnecessary in most cases.

Differential mRNA localization in astroglial cells in culture

Messenger RNA (mRNA) targeting to specific subcellular domains has been studied extensively in many cell types, and there is increasing evidence suggesting that mRNA sorting also occurs in astrocytes. As a step toward developing strategies to evaluate the signals that govern mRNA sorting in astrocytes, the authors studied the subcellular distribution of several representative mRNAs, poly(A) RNA and ribosomal RNA, in process-bearing (type-2) astroglial cells in culture. Nonradioactive in situ hybridization analysis revealed a gradual increase in the expression of glial fibrillary acidic protein (GFAP) mRNA as type-2 astrocytes differentiated in culture. In mature cells, labeling was present in both cell bodies and processes. GFAP mRNA labeling was granular in nature and was particularly concentrated at branch points and at the tips of the processes. Unlike GFAP mRNA, vimentin, beta-tubulin, and beta- and gamma-actin mRNAs were mainly confined to the cell bodies, with only occasional labeling seen in the processes. Nonradioactive and radioactive in situ hybridization analysis of poly(A) and ribosomal RNA, respectively, revealed labeling in cell bodies and processes of immature and differentiated astrocytes. Treatment with nocodazole, a microtubule depolymerizing agent, resulted in a substantial reduction of GFAP mRNA labeling in the processes, whereas treatment with cytochalasin D, a microfilament-disrupting agent, did not alter GFAP mRNA distribution. The results indicate that cultured type-2 astrocytes have the capacity to sort mRNAs to different subcellular domains and that the localization of GFAP mRNA to astrocyte processes requires intact microtubules.

[Exposure to pollutants and allergens in the asthmatic child compared with the healthy child]

To assess the frequency of exposure to allergens and indoor pollutants of school age asthmatic children at the time of their first visit to the specialist, we studied 14 cases with the diagnosis of asthma according to international criteria, and 21 healthy controls. The parents of the children filed a questionnaire asking about socio-economic level, family history of asthma, exposure to allergens or indoor pollutants, and clinical severity of the disease. Questionnaires with less than 80% of the responses were excluded from analysis. Asthmatic patients had higher frequency of exposure to tobacco smoke (42.8% vs 38%), moisture in the home walls (42.9% vs 19%), and to dust reservoirs (71.4% vs 52.4%). A high proportion of the asthmatic patients did not apply adequate environmental control measures. Education for the patients and their primary care physicians must be increased, to reduce the morbidity of the diseases.

Substance P receptors on human astrocytoma cells are linked to glycogen breakdown

In this study we report that substance P stimulated [3H]glycogen breakdown and elevation of intracellular Ca2+ concentration in the human astrocytoma cell line UC-11MG. Both effects were dose dependent, and completely blocked by CP-96,345 suggesting the involvement of an NK1 receptor. Our previous studies indicated that norepinephrine and histamine stimulate glycogenolysis via cAMP and Ca2+ respectively. Combined stimulation with substance P and norepinephrine or histamine resulted in additive effects suggesting that there is no interaction between these neurotransmitters in regulating glycogenolysis in these cells. These results confirm that UC-11MG cells are a useful model system to investigate the functional role of neurotransmitter receptors in astroglial cells.

Mechanisms of regulatory volume decrease in UC-11MG human astrocytoma cells

Swelling of astrocytes commonly occurs after cerebral ischemia and other brain injuries. Because these cells constitute 20-25% of human brain volume, their swelling is a major factor in the morbidity and mortality associated with cerebral edema. Many cells, including astrocytes, resist or reverse the tendency to swell by activating transport pathways that lead to a regulatory volume decrease. Here we report the results of studies designed to elucidate the mechanisms of the regulatory volume decrease that occurs after astrocytes are swollen by exposure to hypotonic medium. Using UC-11MG cells, a well-characterized, human, astrocytoma-derived line, we observed an increase in membrane permeability to both K+ and Cl- during regulatory volume decrease, consistent with a net loss of these ions. Neither the increase in K+ exit nor the regulatory volume decrease was affected by bumetanide, an inhibitor of anion-cation cotransport. On the other hand, the increased K+ efflux, as well as the regulatory volume decrease, was blocked by Gd3+, suggesting a putative role of stretch-activated cationic channels in the process of volume regulation. Although increases in intracellular free Ca2+ were also observed during hypotonic treatment, they occurred well after the onset of the regulatory volume decrease. Furthermore, the regulatory volume decrease was not affected by blocking the intracellular free Ca2+ increase with dimethyl 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid or by removal of extracellular Ca2+. These results indicate that the regulatory volume decrease in UC-11MG cells may involve stretch-activated channels that operate independently of changes in intracellular free Ca2+.

Histamine stimulates glycogenolysis in human astrocytoma cells by increasing intracellular free calcium

Astrocytes from a variety of sources, including the human UC-11MG astrocytoma line, express receptors for histamine on their plasma membranes, but the function of these receptors is largely unknown. Here we report studies on the effect of histamine on newly synthesized glycogen in the human astrocytoma-derived cell line, UC-11MG. We have found [3H]glycogen hydrolysis with a EC50 of 2 microM and a maximum effect of 30% at 300 microM histamine. The glycogenolytic effect of histamine was completely blocked by the H1 receptor antagonist, mepyramine, and was insensitive to the H2 receptor antagonist, cimetidine. Histamine-induced glycogenolysis was significantly reduced in the absence of extracellular Ca2+ and the residual response could be accounted for by Ca2+ released from intracellular stores. The Ca2+ ionophore, ionomycin, induced a similar concentration-dependent increase in both intracellular Ca2+ concentration and in glycogenolysis. These results suggest that one function of astrocytic histamine receptors in vivo may be the stimulation of glucose release from astrocytes, and that this process is mediated by increased intracellular free Ca2+. The glycogenolytic effect of histamine and other neurotransmitters in different systems, and the possible implication of astrocytic glycogenolysis in the pathophysiology of ischemia are discussed.

Characteristics of a presynaptic plasma membrane Ca2(+)-ATPase activity from electric organ

Ca2(+)-ATPase activity was measured in electric organ synaptosomal homogenates and their derived presynaptic plasma membranes using a low ionic strength medium, low in Ca2+ and Mg2+, and devoid of K+. The enzyme activity showed a high apparent affinity for Ca2+ (KCa:0.5 microM) and was: (1) 5-fold stimulated by 120 nM calmodulin, (2) highly sensitive to LaCl3 inhibition, and (3) not affected by 20 mM NaN3 or 0.1 mM ouabain. The addition of Mg2+ promoted the disappearance of Ca2(+)-ATPase activity. Incubation of synaptosomal homogenates in the above-mentioned assay medium with [gamma -32P]ATP resulted in the appearance of a 140 kDa band as revealed by SDS-gel electrophoresis. Labeling of this band with 32P was inhibited by 1 mM EGTA or 10 mM NH2OH, indicating that the isotope incorporation required the presence of Ca2+ and the formation of an acyl-phosphate derivative. The results indicate that the Ca2(+)-ATPase activity from synaptosomal homogenates had characteristics corresponding to those of the enzyme that catalyzes an outward transport of Ca2+ in nerve terminals. Preincubation of synaptosomes in Ca2+ plus K+, a depolarizing procedure, induced a large and rapid decrease in the Ca2(+)-ATPase activity, possibly mediated via Ca2+ entry through voltage-gated Ca2+ channels. Furthermore, the muscarinic cholinergic agonist oxotremorine (at 15 microM concentration) did not significantly affect either the enzyme activity or the intensity of the Ca2(+)-dependent 32P incorporation into the 140 kDa band, suggesting that the enzyme is not coupled to muscarinic binding sites.

The role of transmembrane pH gradients in the lactic acid induced swelling of astrocytes

The swelling of astrocytes is an important component of the morbidity and mortality associated with ischemic brain trauma. In the ischemic brain, lactic acid levels rise dramatically with a concomitant acidification of the extracellular fluid. In this study we have measured the effects of elevated extracellular lactate and reduced extracellular pH (pHo) on astrocyte volume using the human astrocyte-derived cell line UC-11MG. Neither elevated lactate nor reduced pHo alone increased cell volume, but swelling of about 25% was measured when the cells were exposed simultaneously to 20 mM lactic acid and a reduced pHo of 6. The swelling was correlated with an approximately 4-fold increase in intracellular lactate as pHo was decreased from 8.0 to 6.0. As pHo was decreased intracellular pH also decreased, but much more slowly so that at acidic extracellular pH there was an inwardly directed proton gradient. The measured intracellular lactate concentrations closely followed the theoretical levels predicted by a model in which lactate transport is coupled to the inwardly directed proton gradient. Kinetic studies indicated that lactate transport is saturable with a Km of 3.8 mM, consistent with the model for facilitated cotransport of lactate with a proton or exchange of lactate for a hydroxyl ion. These data suggest that an important mechanism of postischemic astrocytic swelling is a proton driven, active accumulation of lactate to levels that result in a significant osmotic gradient of lactate at acidic pH.

Arg-Lys-Asp-Val-Tyr (thymopentin) accelerates the cholinergic-induced inactivation (desensitization) of reconstituted nicotinic receptor

1. The thymic hormone thymopoietin blocks neuromuscular transmission and was proposed (Goldstein, 1974) as a modulator of synaptic conductivity. 2. The cholinergic-induced inactivation of nicotinic receptor reconstituted into asolectin lipid vesicles was studied in the presence and in the absence of thymopentin, a synthetic pentapeptide corresponding to positions 32-36 of thymopoietin. 3. The present data show that thymopentin accelerates desensitization of the nicotinic acetylcholine receptor, supporting the aforementioned physiological role proposed for thymopoietin. 4. They also suggest that the hormone itself and/or a yet unidentified hormine-derived peptide fragment may act as an endogenous ligand for nicotinic acetylcholine receptor desensitization.

Carbamylation of hemoglobin in vivo with chronic sublethal dietary cyanide: implications for hemoglobin S

Carbamylation of the hemoglobin in sickle cell anemia has been demonstrated to improve the status of this hemoglobinopathy. Using an animal model of West African human patterns of chronic sublethal dietary cyanide ingestion, 12 miniature swine consuming either 0, 0.4, 0.7, or 1.2 mg of cyanide/kg body weight/day were studied for 24 weeks to determine if this dietary regime could produce irreversible carbamylated hemoglobin. Throughout the study, the hematological status of all animals remained similar; however, the levels of carbamylated hemoglobin as measured by nanomoles of valine hydantoin varied proportionally to dietary sublethal cyanide intakes, indicating that these natural dietary levels could effect an important and presumably permanent modification of the hemoglobin's beta chain. Serum thiocyanate levels were also positively correlated with cyanide ingestion loads (r = 0.83, P less than 0.01). The implications of these findings in swine are important for the millions of humans with hemoglobin S who regularly consume similar levels of dietary cyanide and for our assessments of the biochemical and medical status of hemoglobin S under natural conditions.

The nicotinic acetylcholine receptor from Discopyge tschudii: purification, characterization and reconstitution into liposomes

The nicotinic acetylcholine receptor from Discopyge tschudii electroplax was purified by affinity chromatography on Affi-Gel 401 using bromoacetylcholine as the ligand. Its specific activity was about 4000 pmol 125I-alpha-bungarotoxin/mg protein. SDS-polyacrylamide gel electrophoresis revealed four bands of apparent molecular weights: 41,200, 49,500, 60,000 and 66,300. The amino acid composition of each individual subunit was determined. Native membranes, rich in nicotinic receptor exhibited carbamylcholine-catalysed cation transport (blocked by curare and desensitized by prior incubation with the cholinergic agonist). The functional activity of the purified material could be reconstituted into soybean lecithin liposomes. Our data show that the Discopyge tschudii nicotinic receptor is similar to that from Torpedo californica.