A mechanical task for measuring sign- and goal-tracking in humans: A proof-of-concept study.

Cue-based associative learning (i.e., Pavlovian conditioning) is a foundational component of behavior in almost all forms of animal life and may provide insight into individual differences in addiction liability. Cues can take on incentive-motivational properties (i.e., incentive salience) through Pavlovian learning. Extensive testing with non-human animals (primarily rats) has demonstrated significant variation among individuals in the behaviors this type of learning evokes. So-named "sign-trackers" and "goal-trackers" have been examined in many studies of non-human animals, but this work in humans is still a nascent area of research. In the present proof-of-concept study, we used a Pavlovian conditioned approach task to investigate human sign- and goal-tracking in emerging adults. Conditioned behaviors that developed over the course of the task were directed toward the reward-cue and toward the reward location. Participants' eye-gaze and behavior during the task were submitted to a latent profile analysis, which revealed three groups defined as sign-trackers (n = 10), goal-trackers (n = 4), and intermediate responders (n = 36). Impulsivity was a significant predictor of the sign-tracking group relative to the goal-tracking group. The present study provides preliminary evidence that a simple procedure can produce learned Pavlovian conditioned approach behavior in humans. Though further investigation is required, findings provide a promising step toward the long-term goal of translating important insights gleaned from basic research into treatment strategies that can be applied to clinical populations.

A cost analysis of outpatient care for patients with Barrett's esophagus in a managed care setting.

OBJECTIVES: Although Barrett's esophagus (BE) may be associated with severe gastroesophageal reflux disease (GERD), there are currently no studies that evaluate resource utilization in Barrett's patients. The aims of this study were 1) to determine the cost and number of endoscopies and clinic visits to the GI clinic for GERD or its complications in patients with BE; 2) to determine the pattern and cost of medication use in patients with BE; and 3) to compare medication use by patients with BE to that of patients with insulin-requiring diabetes mellitus (DM). METHODS: Using the cost distribution report data and the pharmacy acquisition costs from the Durham VAMC, we calculated the monthly cost of endoscopies, clinic visits related to GERD, and medication use in 53 patients with BE between 1/1/94 and 1/1/97. We also calculated the average cost of medication use for 55 patients with insulin-requiring DM. RESULTS: All patients with BE were male. Their median age was 64.0 yr (IQR 57-68). Of them, 92% were white; 23% had low-grade dysplasia (LGD). Patients with LGD were more likely to have more than three endoscopies in 3 yr than were those with no LGD (OR 6.3, 95% CI 1.11-35.67). There was no difference in clinic visits in the patients with and without dysplasia (OR 0.335, 95% CI 0.093-1.206). A total of 139 endoscopies and 172 clinic visits were observed. Outpatient care for patients with BE costs approximately $103/month or $1241/yr. Endoscopies and clinic visits accounted for 31.1% and 5.9% of the monthly medical cost, respectively. Medications accounted for 63% of the total cost of care. Prokinetic agents accounted for 0.8% of the total cost of medications, whereas histamine receptor antagonists (H2 blockers) and proton pump inhibitors (PPIs) accounted for 34.6% and 64.6%, respectively. Medication cost per month in patients with BE was approximately $65, similar to that of patients with insulin-requiring DM ($63). CONCLUSIONS: Our conclusions were as follows: 1) Outpatient care for patients with BE costs approximately $1241/yr or ($103/month). 2) Medication use per month accounted for more than half of the total cost; PPIs accounted for 64.6% of total medication cost, suggesting that reflux was severe. 3) Consistent with current surveillance strategies, patients with LGD had more frequent endoscopy than patients with no dysplasia. 4) Medication cost per month in patients with BE is similar to that in patients with DM, another group with a chronic disorder. 5) Those who make health policy can use these results to compare the cost of care of patients with BE to the cost for those with other chronic medical disorders.

[Seroepidemiological study of toxoplasmosis in Libreville, Gabon]. / Etude séro-épidémiologique de la toxoplasmose à Libreville, Gabon.

A sero-epidemiological survey of toxoplasmosis has been carried out in 1178 subjects residing in urban and suburban areas of Libreville, Gabon. Two techniques were used: Pastorex toxo of the Institut Pasteur and ISAGA of bioMérieux. The acquisition of antibodies occurs at an early age, from the age of six months on. After the age of 15 years, the age of procreation, the prevalence is 68%. Between the ages of 15 and 19 years, 19% have IgM. The risk for toxoplasmosis acquired during pregnancy is not to be neglected. It decreases between the ages of 20 and 30 years. The most probable source of contamination is the reservoir from the soil. No difference between the sexes was observed.

[Parasitemia in Plasmodium falciparum malarial attacks in children]. / Parasitémie au cours des accès palustres à Plasmodium falciparum chez l'enfant.

In order to evaluate the predictive value of parasitaemia, this parameter was measured on admission in 69 Gabonese children aged from 3 to 13 years hospitalized for Plasmodium falciparum malarial attacks. Fourteen of these children had cerebral malaria, 5 had isolated convulsions and 50 had uncomplicated attacks. The parasitaemia values measured were compared with those found in asymptomatic children of the same age range carrying trophozoites. There were no significant differences in mean parasitaemia count between the 3 types of malarial attack, and only the asymptomatic carriers had significantly lower counts. However, the wide scattering of individual values within each group indicated that simple measurement of parasitaemia is not discriminative enough to predict the course of malarial attacks in children living in endemic regions. In particular, malarial attacks with very low or very high parasitaemia value are possible, but similar values are found in asymptomatic carriers.

[Malaria and hemoglobin S: interactions in African children]. / Paludisme et hémoglobine S: interactions chez l'enfant africain.

Among 300 cases of Plasmodium falciparum malaria attacks explored in Gabon, the proportion of homozygous (SS) or heterozygous (AS) sickle-cell patients was 6.2 percent in 206 ordinary attacks and 3.2 percent in 94 cerebral malaria attacks, and 23.2 percent in the general population. On the other hand, asymptomatic carriage, as detected in 98 children by thin blood films in school screening, was as frequent in the SS or AS infantile population as in the general population. These data show that haemoglobin S protects effectively, although not entirely, against severe attacks of P. falciparum malaria. The incidence of anaemia and vaso-obstructive crisis in malaria-infested sickle-cell patients suggests that subclinical carriage of haematozoa may worsen the course of sickle-cell disease, and this must be taken into account when planning treatment.

Efficacy, safety and acceptability of halofantrine in the treatment of acute Plasmodium falciparum malaria in African children (Gabon).

Halofantrine chlorhydrate 2 per cent suspension was given to 50 children (mean age 6.2 years in a dose of 8 mg/kg three times a day as a single day treatment. The children were born and lived in Gabon, where malaria transmission is continuous. They all had acute Plasmodium falciparum malaria. The children were kept in hospital for 5 days, and regularly followed over a 15-day period. The 50 children were cured and efficacy was evaluated as good in 44 cases, and excellent in six cases, as judged by improvement in their clinical signs and parasitaemia. Two criterias were considered in the evaluation of efficacy: clearance of parasitaemia (mean day 4), fever clearance (mean hour 24). There were two cases of persistences of parasites at day 15 with a very low parasitaemia rate. Tolerance to halofantrine was good from a clinical and biological point of view. Acceptability was excellent in all cases. Halofantrine 2 per cent suspension is a good alternative in the treatment of acute Plasmodium falciparum malaria in children, especially with the present situation of multidrug-resistant strains in Central Africa.

[Toxoplasmosis in Gabon. Results of a seroepidemiological investigation]. / Toxoplasmose au Gabon. Résultats d'une enquête séro-épidémiologique.

A toxoplasmosis sero-epidemiological inquiry was effected with 2,324 sera collected from Libreville, Lébamba, Makokou, Lastourville and Woleu-Ntem. All the sera were first screened through Pastorex toxo (Diagnostics Pasteur). Those with more 8 IU/ml and 267 sera with less 8 IU/ml were then assayed by ISAGA (bioMerieux) for IgM. The results of ISAGA must be interpreted with carefulness for natural agglutinins are frequent in this population. The acquisition of immunity is precoce and more of 60% have a serology positive from ten years old. There was no difference between sex.

Premiere description de foyers d'onchocercose humaine au Gabon

Des foyers d'onchocercose a Onchocerca volvulus sont decrits pour la premiere fois au Gabon. Au cours des memes enquetes on note de fortes prevalences de porteurs de M. streptocerca et la premiere description chez l'homme de M. Rodhaini. 4922 sujets au cours de 10 enquetes portant sur l'ensemble du territoire gabonais ont subi une biopsie cutanee exsangue; un prelevement sanguin; un examen clinique. La prevalence globale des porteurs de O. volvulus est de 19;4 pour cent. Les regions les plus touchees sont : Makokou; Lebamba; Fougamou; Lastourville. Les hommes sont plus atteints que les femmes. L'infestation debute tot : 1;9 pour cent des enfants de 0-4 ans sont porteurs de microfilaires. La charge microfilarienne moyenne est de 30;7 microfilaires d'O. volvulus par biopsie. Les manifestations cliniques sont pauvres comparees a l'Afrique de l'Ouest : 36;3 pour cent des onchocerquiens sont porteurs de nodules. Les etudes des lesions oculaires n'ont porte que sur le segment anterieur de l'oeil; le pour centage de keratites ponctuees est moins important qu'en Afrique Sahelien

[Role of cryptosporidiosis in infants in Gabon. Results of two prospective studies]. / Place de la cryptosporidiose chez l'enfant au Gabon. Résultats de deux enquetes prospectives.

Two epidemiological surveys of cryptosporidiosis in urban and suburban areas of Libreville, Gabon, Equatorial Africa, were conducted in children. On 450 fecal samples on the first study, Cryptosporidium sp. has been seen about 3.11%. For the second survey, on 296 children, aged between 0 and 2 years, with acute diarrhoea, the rate of infestation was 24%. The maxima was observed for infants aged between 6-18 months, in case of malnutrition and during wet seasons.

Hendersonula toruloidea as an agent of mycotic foot infection in Gabon.

Pathogenic fungi were isolated from 149 of 210 Gabonese patients with clinical signs of tinea pedis. Hendersonula toruloidea was isolated from 51 patients (34.2%), either alone (in 25%) or in association with a dermatophyte species or Candida albicans. Clinical signs of H. toruloidea infection closely resembled those of dermatophyte infection except that hyperkeratinization of the soles was most often associated with infection by H. toruloidea. H. toruloidea mycelium could be readily distinguished from dermatophyte mycelium on direct examination of skin scrapings. All the H. toruloidea isolates closely resembled the Type 1 isolates described by Moore, both microscopically and macroscopically. The importance of establishing a mycological diagnosis of this infection and the therapeutic implications of infection with H. toruloidea are discussed. This fungus was isolated from 34% of our patients from Gabon with clinical tinea pedis.

[Development of chloroquine resistance in Plasmodium falciparum in Gabon between 1984 and 1987-88 (in vivo evaluation in a school environment)]. / Evolution de la résistance de Plasmodium falciparum à la chloroquine au Gabon entre 1984 et 1987-88 (evaluation in vivo en milieu scolaire).

Unknown in 1980, suspected in 1983 and scarcely present in 1984-85, Plasmodium falciparum resistance to chloroquine as studied in vivo in schoolchildren in Gabon, has strongly developed in 4 years time. In 1987-88, administration of 25 mg/kg of chloroquine leaves one strain out of four with a parasitic load greater than 10/1.000 red blood cells examined by thick drop technique. The present, unfortunately provisional attitude tends to maintain chloroquine at efficient doses for as long as the resistant strains are ethically and practically controllable. The dispersion without strict control of new and for the time being very efficient drugs might rapidly give rise to a polychemoresistance which would leave us without defence.

[Malaria in Gabon. Bioclinical survey of non immune Europeans during short stay and prophylactic attitude]. / Paludisme au Gabon. Enquête bioclinique chez des sujets européens non immuns en court séjour et attitude prophylactique.

A group of 300 young European adults visiting Gabon for relatively short periods was surveyed monthly for malaria from a parasitological, clinical, immunological, hematological point of view. The regular increase of fevers due to malaria from 1984 to 1988 and the multiplication of cases of amino-4-quinoline resistance in the plasmodial parasites call for new prophylactic considerations for this group residing in this heavily malaria infested area.

[Malaria in Gabon. Transplacental passage and dynamics of development of fluorescent antimalarial antibodies with age]. / Paludisme au Gabon. Passage transplacentaire et dynamique de développement des anticorps antipalustres fluorescents selon l'âge.

In permanent malaria transmission area (Gabon), fluorescent malarial antibodies have been studied among a population of mothers new borns and children from 1 to 15 years old. A lack of transplacental transfer of antibodies among african pairs "cord-mother" is noticed and in negative correlation with total mother IgG level. The antibodies rapidly increase from 1-2 years old still 9. Chimioprophylaxis does'nt modified for a long time the development of the FAT malarial antibodies.

Evoked potential changes and neuropsychological performance in Parkinson's disease.

Auditory brainstem responses (ABRs) and long latency exogenous and endogenous auditory evoked potentials (EPs) were investigated in 16 patients with Parkinson's disease and 11 control subjects. Parkinson's disease patients were impaired on mental status testing. While ABRs and the N1 component of the auditory EP were of normal latency in Parkinson patients, the endogenous components, N2 and P3, were prolonged. Prolongation of P3 latency in Parkinson's disease correlated with mental status decline, but not with severity of motoric disturbance. Thirteen PD patients also received neuropsychological evaluation. P3 latency was correlated with tests requiring learning or mental manipulation of information, but not with measures of verbal performance, immediate memory, or depression. P3 latency prolongation appears to have a selective relationship to intellectual changes in PD, and may be most sensitive to deficits requiring significant cognitive effort.

[Malaria in Gabon. 2. Evaluation of the qualitative and quantitative prevalence of parasites in the total school and preschool population of the country]. / Le paludisme au gabon. 2. Evaluation des prévalences parasitaires qualitatives et quantitatives sur l'ensemble du pays en milieu scolaire et préscolaire.

The distribution of carriers of hematozoa in the pre-school and school age group in Gabon has been established with the help of systematic enquiry. The plasmodial indexes vary between 11 and 32% in the savanna zones of the south-east, they rise to 64.9% in the forest regions of the north of the country, and in the urban zones (Libreville, Franceville, Lambarene) 6 to 18% of the school children are gametocyte carriers. In Libreville, amongst the febrile children seen in pediatric consultation, the prevalence reached 30%. Boys and girls are equally affected. The most important prevalence is observed in the group of children from 5 to 10 years of age. P. falciparum is found in 96.4% of the cases, P. malariae in 5.3% and P. ovale in 2.4%. The study of the parasitic load revealed that 56% of the positive subjects had less than 10,000 asexual forms/mm3, 44% more than 10,000 hematozoa/mm3. These results are similar to those of the neighbouring countries of equatorial Africa.

Acoustic analysis: an objective measure of affective flattening.

Acoustic analysis of voice patterns is an objective means of evaluating flatness of affect. Thirty-one patients defined as having flat affect by a reliable rating scale were compared with 30 patients who were not flat. The hypothesis that flat patients display monotonic speech was confirmed, for these patients showed less variance in both the amplitude and frequency of their speech than the nonflat patients.

Esophagogastrostomy with the EEA stapler.

Esophagogastric anastomosis was performed with the EEA stapler in 31 patients who underwent esophageal resections. Anastomoses were accomplished at all levels of the thoracic and cervical esophagus by a variety of approaches. Routine barium cine-esophagograms obtained at seven days after operation failed to demonstrate an anastomotic leak in any patient. The operative mortality rate was 3% (1 of 31 patients). Technical problems occurred during the operation in three patients; in two of these an incomplete anastomosis may have resulted from the surgeon's error. All patients were able to swallow normally at the time of discharge. Late anastomotic stricture occurred in five patients, and responded to dilatation in all but one patient who had local tumor recurrence. We conclude that the EEA stapler allows rapid and reliable esophagogastric anastomosis. Successful use of the instrument requires strict attention to technical detail and awareness of possible pitfalls.