A clinical study of kuru patients with long incubation periods at the end of the epidemic in Papua New Guinea

Kuru is so far the principal human epidemic prion disease. While its incidence has steadily declined since the cessation of its route of transmission, endocannibalism, in Papua New Guinea in the 1950s, the arrival of variant Creutzfeldt–Jakob disease (vCJD), also thought to be transmitted by dietary prion exposure, has given kuru a new global relevance. We investigated all suspected cases of kuru from July 1996 to June 2004 and identified 11 kuru patients. There were four females and seven males, with an age range of 46–63 years at the onset of disease, in marked contrast to the age and sex distribution when kuru was first investigated 50 years ago. We obtained detailed histories of residence and exposure to mortuary feasts and performed serial neurological examination and genetic studies where possible. All patients were born a significant period before the mortuary practice of transumption ceased and their estimated incubation periods in some cases exceeded 50 years. The principal clinical features of kuru in the studied patients showed the same progressive cerebellar syndrome that had been previously described. Two patients showed marked cognitive impairment well before preterminal stages, in contrast to earlier clinical descriptions. In these patients, the mean clinical duration of 17 months was longer than the overall average in kuru but similar to that previously reported for the same age group, and this may relate to the effects of both patient age and PRNP codon 129 genotype. Importantly, no evidence for lymphoreticular colonization with prions, seen uniformly in vCJD, was observed in a patient with kuru at tonsil biopsy

Motor-Incompatibility of Facial Reactions : The influence of valence and stimulus content on voluntary facial reactions

Emotional cues facilitate motor responses that are associated with approach or avoidance. Previous research has shown that evaluative processing of positive and negative facial expression stimuli is also linked to motor schemata of facial muscles. To further investigate the influence of different types of emotional stimuli on facial reactions, we conducted a study with pictures of emotional facial expressions (KDEF) and scenes (IAPS). Healthy participants were asked to respond to the positive or negative facial expressions (KDEF) and scenes (IAPS) with specific facial muscles in a valence-congruent (stimulus valence matches muscle related valence) or a valence-incongruent condition (stimulus valence is contrary to muscle related valence). Additionally, they were asked to rate pictures in terms of valence and arousal. Muscular response latencies were recorded by an electromyogram. Overall, response latencies were shorter in response to facial expressions than to complex pictures of scenes. For both stimulus categories, response latencies with valence-compatible muscles were shorter compared to reactions with incompatible muscles. Moreover, correlations between picture ratings and facial muscle reactions for happy facial expressions as well as positive scenes reflect a direct relationship between perceived intensity of the subjective emotional experience and physiological responding. Results replicate and extend previous research, indicating that incompatibility effects are reliable across different stimulus types and are not limited to facial mimicry

Inhibition of return in fear of spiders: Discrepant eye movement and reaction time data

Inhibition of return (IOR) refers to a bias against returning the attention to a previously attended location. As a foraging facilitator it is thought to facilitate systematic visual search. With respect to neutral stimuli, this is generally thought to be adaptive, but when threatening stimuli appear in our environment, such a bias may be maladaptive. This experiment investigated the influence of phobia-related stimuli on the IOR effect using a discrimination task. A sample of 50 students (25 high, 25 low in spider fear) completed an IOR task including schematic representations of spiders or butterflies as targets. Eye movements were recorded and to assess discrimination among targets, participants indicated with button presses if targets were spiders or butterflies. Reaction time data did not reveal a significant IOR effect but a significant interaction of group and target; spider fearful participants were faster to respond to spider targets than to butterflies. Furthermore, eye-tracking data showed a robust IOR effect independent of stimulus category. These results offer a more comprehensive assessment of the motor and oculomotor factors involved in the IOR effect

Nurses\u27 Alumnae Association Bulletin - Volume 7 Number 11

Anna M. Shafer Barton Memorial Division Births Changes in the Ophthalmology Division Change of Address Clara Melville Fund Continental Tour Deceased Digest of Meetings Inter-County Hospitalization Plan Katherine Childs\u27 Letter Lost Members Marriages Miscellaneous Nursing Home Committee\u27s Report Physical Advantages President James L. Kauffman\u27s Letter President\u27s Greeting Private Duty Section Prizes Relief Fund School Nursing Silhouette of a Public Health Nurse Rooming-in of Infant with Mother Staff Activities The Student White Haven Divisio

Genetic susceptibility, evolution and the kuru epidemic

The acquired prion disease kuru was restricted to the Fore and neighbouring linguistic groups of the Papua New Guinea highlands and largely affected children and adult women. Oral history documents the onset of the epidemic in the early twentieth century, followed by a peak in the mid-twentieth century and subsequently a well-documented decline in frequency. In the context of these strong associations (gender, region and time), we have considered the genetic factors associated with susceptibility and resistance to kuru. Heterozygosity at codon 129 of the human prion protein gene (PRNP) is known to confer relative resistance to both sporadic and acquired prion diseases. In kuru, heterozygosity is associated with older patients and longer incubation times. Elderly survivors of the kuru epidemic, who had multiple exposures at mortuary feasts, are predominantly PRNP codon 129 heterozygotes and this group show marked Hardy–Weinberg disequilibrium. The deviation from Hardy–Weinberg equilibrium is most marked in elderly women, but is also significant in a slightly younger cohort of men, consistent with their exposure to kuru as boys. Young Fore and the elderly from populations with no history of kuru show Hardy–Weinberg equilibrium. An increasing cline in 129V allele frequency centres on the kuru region, consistent with the effect of selection in elevating the frequency of resistant genotypes in the exposed population. The genetic data are thus strikingly correlated with exposure. Considering the strong coding sequence conservation of primate prion protein genes, the number of global coding polymorphisms in man is surprising. By intronic resequencing in a European population, we have shown that haplotype diversity at PRNP comprises two major and divergent clades associated with 129M and 129V. Kuru may have imposed the strongest episode of recent human balancing selection, which may not have been an isolated episode in human history

What's the risk? Fearful individuals generally overestimate negative outcomes and they dread outcomes of specific events

Although it is an adaptive mechanism that danger usually elicits fear, it seems that fearful individuals overestimate the danger associated with their feared objects or situations. Previous research has not systematically distinguished between the estimated risk of an encounter with fear-relevant stimuli and the expected unpleasant outcomes of such encounters. Furthermore, it is not clear if biased risk perception is specific to an individual’s fear or generalized to all negative events. In an online-survey (N = 630) we assessed the estimated risk to encounter fear-relevant stimuli and the expectations of negative outcomes of such encounters. Items contained three domains (spiders, snakes, and everyday fear triggers). In regression analyses we examined the specific associations between fear and risk estimations. In addition, we compared subgroups with specific fears and low fearful individuals. While an individual’s fear score was not related to the estimated risk of an encounter with fear-specific stimuli, it was related to an overestimation of negative outcomes in all domains. The perceived risk of aversive outcomes was most pronounced for an individual’s specific fear. Furthermore, an individual’s specific fear was most predictive of the estimated risk of a negative fearrelevant outcome. Highly fearful individuals overestimate the risk of negative outcomes of fear-relevant encounters. Specifically, they dread outcomes of encounters with their feared object. Differentiating fear-relevant components of risk perception provides insights into the cognitions which may motivate maladaptive avoidance behavior