Age-related Differences In Susceptibility Research Articles

Supplemental Material for Adult Age-Related Differences in Susceptibility to Social Conformity Pressures in Self-Control Over Daily Desires

Supplemental Material for Adult Age-Related Differences in Susceptibility to Social Conformity Pressures in Self-Control Over Daily Desires

Adult age-related differences in susceptibility to social conformity pressures in self-control over daily desires.

Developmental literature suggests that susceptibility to social conformity pressure peaks in adolescence and disappears with maturity into early adulthood. Predictions about these behaviors are less clear for middle-aged and older adults. On the one hand, while age-related increases in prioritization of socioemotional goals might predict greater susceptibility to social conformity pressures, aging is also associated with enhanced emotion regulation that could support resistance to conformity pressures. In this exploratory research study, we used mobile experience sampling surveys to naturalistically track how 157 healthy adults between the ages of 18 and 80 practice self-control over spontaneous desires in daily life. Many of these desires were experienced in the presence of others enacting that desire. Results showed that middle-aged and older adults were better at controlling their desires than younger adults when desires were experienced in the presence of others enacting that desire. Consistent with the literature on improved emotion regulation with age, these results provide evidence that the ability to resist social conformity pressure is enhanced across the adult life span. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Age-Associated Changes in Recombinant H5 Highly Pathogenic and Low Pathogenic Avian Influenza Hemagglutinin Tissue Binding in Domestic Poultry Species.

Simple SummaryWe evaluated differences in avian influenza H5 Hemagglutinin (HA) tissue binding across age groups using recombinant H5 HA (rHA) proteins. Gene sequences from low pathogenic (LPAIV) (A/mallard/MN/410/2000(H5N2) and an a high pathogenic (HPAIV) (A/Northern pintail/Washington/40964/2014(H5N2)) influenza A virus (IAV) were used to generate the rHA proteins. Respiratory and intestinal tracts from chickens, ducks (Mallard, Pekin, Muscovy), and turkeys of different age groups were used to detect rHA binding with protein histochemistry, which was quantified as the median area of binding (MAB) for statistical analysis. Turkeys had significant differences in the HPAIV rHA binding in the respiratory tract, with younger turkeys having higher levels of binding in the lung compared to the older group. In the intestinal tract, younger turkeys had higher levels of binding compared to the older birds. Using LPAIV, only turkeys had overall significant differences in the respiratory tract MAB, with the older birds having higher levels of binding compared to the younger group. We saw no age-related differences in the overall intestinal tract rHA binding. Age-related differences in rHA binding of the LPAIV and HPAIV rHA demonstrated in this study may partially, but not completely, explain differences in host susceptibility to infection observed during avian influenza outbreaks and in experimental infection studies.The 2014 outbreak of clade 2.3.4.4A highly pathogenic avian influenza (HPAI) led to the culling of millions of commercial chickens and turkeys and death of various wild bird species. In this outbreak, older chickens and turkeys were commonly infected, and succumbed to clinical disease compared to younger aged birds such chicken broilers. Some experimental studies using waterfowl species have shown age-related differences in susceptibility to clinical disease with HPAI viruses. Here, we evaluate differences in H5 Hemagglutinin (HA) tissue binding across age groups, using recombinant H5 HA (rHA) proteins generated using gene sequences from low pathogenic (A/mallard/MN/410/2000(H5N2 (LPAIV)) and a HPAIV (A/Northern pintail/Washington/40964/2014(H5N2)) influenza A virus (IAV). Respiratory and intestinal tracts from chickens, ducks (Mallard, Pekin, Muscovy) and turkeys of different age groups were used to detect rHA binding with protein histochemistry, which was quantified as the median area of binding (MAB) used for statistical analysis. There were species and tissue specific differences in the rHA binding among the age groups; however, turkeys had significant differences in the HPAIV rHA binding in the respiratory tract, with younger turkeys having higher levels of binding in the lung compared to the older group. In addition, in the intestinal tract, younger turkeys had higher levels of binding compared to the older birds. Using LPAIV, similar species and tissues, specific differences were seen among the age groups; however, only turkeys had overall significant differences in the respiratory tract MAB, with the older birds having higher levels of binding compared to the younger group. No age-related differences were seen in the overall intestinal tract rHA binding. Age-related differences in rHA binding of the LPAIV and HPAIV demonstrated in this study may partially, but not completely, explain differences in host susceptibility to infection observed during avian influenza outbreaks and in experimental infection studies.

Age influences susceptibility of brain capillary endothelial cells to La Crosse virus infection and cell death

BackgroundA key factor in the development of viral encephalitis is a virus crossing the blood-brain barrier (BBB). We have previously shown that age-related susceptibility of mice to the La Crosse virus (LACV), the leading cause of pediatric arbovirus encephalitis in the USA, was associated with the ability of the virus to cross the BBB. LACV infection in weanling mice (aged around 3 weeks) results in vascular leakage in the olfactory bulb/tract (OB/OT) region of the brain, which is not observed in adult mice aged > 6–8 weeks. Thus, we studied age-specific differences in the response of brain capillary endothelial cells (BCECs) to LACV infection.MethodsTo examine mechanisms of LACV-induced BBB breakdown and infection of the CNS, we analyzed BCECs directly isolated from weanling and adult mice as well as established a model where these cells were infected in vitro and cultured for a short period to determine susceptibility to virus infection and cell death. Additionally, we utilized correlative light electron microscopy (CLEM) to examine whether changes in cell morphology and function were also observed in BCECs in vivo.ResultsBCECs from weanling, but not adult mice, had detectable infection after several days in culture when taken ex vivo from infected mice suggesting that these cells could be infected in vitro. Further analysis of BCECs from uninfected mice, infected in vitro, showed that weanling BCECs were more susceptible to virus infection than adult BCECs, with higher levels of infected cells, released virus as well as cytopathic effects (CPE) and cell death. Although direct LACV infection is not detected in the weanling BCECs, CLEM analysis of brain tissue from weanling mice indicated that LACV infection induced significant cerebrovascular damage which allowed virus-sized particles to enter the brain parenchyma.ConclusionsThese findings indicate that BCECs isolated from adult and weanling mice have differential viral load, infectivity, and susceptibility to LACV. These age-related differences in susceptibility may strongly influence LACV-induced BBB leakage and neurovascular damage allowing virus invasion of the CNS and the development of neurological disease.

False recognitions in short-term memory – Age-differences in neural activity

While the knowledge on age-related differences in susceptibility to episodic false memories is extensive, little is known about this phenomenon in visual short-term memory (STM). Our previous behavioural research indicated that older adults are more confident of their erroneous STM recognitions than young adults. However, unlike in episodic memory, we did not find support for older adults’ higher rate of false alarms. To further understand this specific age-difference, here we investigated its neural correlates. First, the pattern of behavioural results replicated the one from our previous experiment. Second, younger adults, when compared to older adults, exhibited higher false recognition-related activity of the visual cortex, the anterior cingulate cortex, the frontal operculum/insular cortex as well as regions within the anterior and dorsolateral prefrontal cortex. No age-differences were observed in hippocampal activity. Third, younger but not older adults presented higher activity in the anterior cingulate cortex and the frontal operculum/insular cortex for false recognitions when compared to highly confident correct rejections. Finally, frontal activity was influenced by both the individuals’ performance and their metacognitive abilities. The results suggest that age-related differences in confidence of STM false recognitions may arise from age-differences in performance monitoring and uncertainty processing rather than in hippocampal-mediated binding.

Pentylenetetrazole-induced Seizure Susceptibility in the Tau58/4 Transgenic Mouse Model of Tauopathy

In several tauopathies such as Alzheimer’s disease (AD), an increased incidence of seizures is observed. Tau, one of the major proteins implicated in AD pathology, is an important regulator of neural network excitability and might participate in the underlying epileptic cascade. However, the mechanisms underlying this relationship are not fully elucidated. We aim to investigate this mechanism by analyzing seizure susceptibility to the convulsant pentylenetetrazole (PTZ) in a novel rodent tauopathy model. A single dose of PTZ was systemically injected in Tau58/4 transgenic mice. To investigate whether young and aged heterozygous (HET) mice exhibit a higher susceptibility to seizures in comparison with wild-type (WT) littermates, video electroencephalography (EEG) in combination with behavioral scoring according to a modified Racine scale was used. The employment of different dosage groups enabled us to characterize the dose range reliably inducing seizures. Here, we report an increased seizure susceptibility in young but not in old HET Tau58/4 mice. Young HET animals displayed more severe seizures and had a reduced latency to the first seizure compared to WTs. Also, age-related differences in susceptibility could be demonstrated for both genotypes. Identification and targeting of secondary diseases such as epilepsy, which aggravate dementia and lead to earlier institutionalization, is key. This study finds that tau pathology itself is sufficient to alter seizure susceptibility in a rodent model, indicating that the disease process is crucial in the emergence of epilepsy in patients with tauopathy.

Pathogenicity comparison of duck Tembusu virus in different aged Cherry Valley breeding ducks

BackgroundAlthough several studies have revealed that the sensitivity of ducklings to duck Tembusu virus (DTMUV) was related to age, however, DTMUV was originally isolated from egg-laying ducks, and the ovary was the target organ of this virus. Cherry Valley breeding ducks aged 15- and 55-week-old (they are reserve breeding ducks and the normal egg-laying breeding ducks, respectively) were infected with DTMUV, using intramuscular injection, to study the effect of age-related difference on the pathogenicity of DTMUV in breeding ducks.ResultsExaminations of clinical symptoms, gross and microscopic lesions, viral loads, cytokines and serum neutralizing antibodies were performed. Results showed that obvious clinical symptoms, such as depression, ruffled feathers, ataxia and egg-laying drop were observed in the 55-week-old laying ducks, with five ducks dying at 5–7 days post infection (dpi). The 15-week-old ducks showed slight symptoms during infection. Gross lesions were severe and characterized by the congestion, hemorrhage and swelling of some organs in the 55-week-old ducks, including the hemorrhage of endocardium, hepatomegaly, splenomegaly, oviduct hemorrhage, hyperemia and deformation of the ovary. Mild endocardial hemorrhage and hepatosplenomegaly were observed in the 15-week-old ducks. Similarly, there was a significant difference in microscopic lesions between the two groups. The older ducks displayed severe microscopic lesions, specifically in the hemorrhage, interstitial inflammatory cell infiltration of the endocardium, typical viral encephalitis and hemorrhage in the ovary. But on the whole, the 15-week-old ducks showed milder lesions. Viral loads in tissues of the older group were significantly higher than those of the younger group. The levels of interferon (IFN)-γ, interleukin (IL)-2 and neutralizing antibody in the 15-week-old ducks were higher than in the 55-week-old ducks at the early stage of the DTMUV infection, suggesting the immune response in the younger ducks to DTMUV was stronger than in the older ducks.ConclusionsThese results demonstrated that age-related differences in susceptibility to DTMUV in breeding ducks was significant, with 55-week-old egg-laying ducks being more susceptible to DTMUV than 15-week-old reserve breeding ducks.

Safety of Injectable HPβCD-Diclofenac in Older Patients with Acute Moderate-to-Severe Postoperative Pain: A Pooled Analysis of Three Phase III Trials

BackgroundHydroxypropyl-β-cyclodextrin-diclofenac (HPβCD-diclofenac) is an NSAID used to treat acute moderate-to-severe postoperative pain. This post hoc analysis investigated the safety of HPβCD-diclofenac in patients aged ≥ 65 years.MethodsData from three phase III trials of HPβCD-diclofenac in adult patients with acute moderate-to-severe postoperative pain were pooled (NCT00448110, NCT00507026, and NCT00726388). Patients who received one or more dose of HPβCD-diclofenac or placebo were included and stratified according to age: < 65, 65–74, or ≥ 75 years. Numerical and categorical variables were compared across the groups using ANOVA and Cochran–Mantel–Haenszel tests, respectively. Cochran–Mantel–Haenszel relative risks compared with placebo were calculated, adjusted by study.ResultsOverall, 1289 patients were included: 878, 282, and 129 in the < 65, 65–74, and ≥ 75-years groups, respectively. Overall incidence of treatment-emergent adverse events (TEAEs) was similar in the three groups (p = 0.4360). Incidences of postoperative anemia (p < 0.0001), constipation (p = 0.0017), and hypotension (p = 0.0003) increased significantly across the age groups, whereas headache (p = 0.0008) and flatulence (p = 0.0118) decreased significantly. Relative risks for all System Organ Class categories and preferred terms investigated were similar among the groups and similar to placebo.ConclusionsOverall incidence of TEAEs in patients aged 65–74 or ≥ 75 years was similar to patients aged < 65 years. The groups displayed similar relative risks for the most frequent TEAEs, which were all similar to placebo. The TEAE profiles of the groups showed differences, all of which may be anticipated due to age-related differences in susceptibility and the types of surgery most commonly performed in each group.Clinicaltrials.gov identifiersNCT00448110, NCT00507026, and NCT00726388.

Role of Emotion and Cognition on Age Differences in the Framing Effect.

Framing effect studies indicate that individuals are risk averse for decisions framed as gains but risk-seeking for decisions framed as losses. Findings of age-related differences in susceptibility to framing are mixed. In the current study, we examined emotional arousal in two decision tasks (life saving vs. money gambling) to evaluate the effects of emotion on age differences in the framing effect. When cognitive abilities and styles were controlled, there was a framing effect in the younger group in the life-saving task, a high-emotional arousal task, while older adults did not display this classic framing effect pattern. They showed risk aversion in both positive and negative framing. Age differences existed in the framing effect. Conversely, younger and older adults in the money-gambling task both displayed the framing effect; there was no age difference. When the cognitive abilities were not controlled, the pattern of results in the high-emotional arousal task remained unchanged, while greater framing effects were found, from the perspective of effect size, for older than younger adults in the low-emotional arousal task. Limited cognitive resources would not hamper older adults' performances when their emotional arousal was high. However, older adults with low-level emotional arousal were more susceptible than younger adults to framing because of declining cognitive capacities. This implied the importance of emotion in older adults' decision making and supported the selective engagement hypothesis.

Evidence for effects on thermoregulation after acute oral exposure to type I and type II pyrethroids in infant rats

Most pyrethroid (PYR) insecticides may be classified either as type-I compounds, which produce whole body tremors and hyperthermia, or type-II compounds, which produce salivation, choreoathetosis, and hypothermia (i.e., producing T and CS neurobehavioral syndromes, respectively). This classification is based on clinical observations in adult rats and mice after intracerebroventricular or intravascular administration of highly effective acute (bolus) doses. PYR neurotoxicity in infant animals is not characterized as much as in adult animals. Endpoints informing on vital determinants of mammal's maturation, such as body temperature may help recognizing age-related differences in susceptibility to PYRs. In this work, body temperature (Tb) was monitored at 30-min intervals after acute oral exposure to T-syndrome PYR bifenthrin (BIF), CS-syndrome PYR cypermethrin (CYPM), and a BIF–CYPM mixture in weanling rats by using a subcutaneous temperature monitoring system. In both single-compound assays, a time- and dose-related decline of Tb was the most evident impact on thermoregulation observed starting at ~2–3h after dosing. Moreover, 15–18mg/kg BIF induced a mild increase in Tb before the hypothermic action was apparent. The lowest effective dose for temperature perturbation was 15mg/kg for BIF and 10mg/kg for CYPM, and moderate neurobehavioral alterations were evident at 12 and 10mg/kg, respectively. When low effective doses of BIF and CYPM were co-administered mild behavioral effects and a transient increase in Tb (p=0.02) were observed at 1–2h, and no Tb decline was apparent afterwards compared to control animals. Noteworthy, the hypothermic action of BIF in infant rats was quite different from the hyperthermia consistently reported in studies using mature animals. Our results suggest that body temperature monitoring may be useful as a complementary assessment to reveal qualitative age-specific pesticide effects in rats.

Age-related differences in distractor interference on line bisection.

Using a bisection paradigm, we investigated age-related differences in susceptibility to distractor interference. Older and younger participants were asked to bisect a horizontal line flanked by a pair of distractors, placed in either left or right hemispace. The results showed that (1) in both groups the distractors interfered with line bisection so that the localization of subjective midpoint was selectively shifted away from their position; (2) the shifting of subjective midpoint was greater in the older than in the younger group when the distractors were placed in the left hemispace. We suggest that the increase of the bisection bias in the older group depends on changes in attentional mechanisms involved in inhibiting irrelevant information.

Susceptibility to the amphibian chytrid fungus varies with ontogeny in the direct-developing frog, Eleutherodactylus coqui.

Age-related differences in susceptibility to infectious disease are known from a wide variety of plant and animal taxonomic groups. For example, the immature immune systems of young vertebrates, along with limited prior exposure to pathogens and behavioral factors, can place juveniles at greater risk of acquiring and succumbing to a pathogen. We studied the ontogenetic susceptibility of terrestrial direct-developing frogs (Eleutherodactylus coqui) to the fungal pathogen, Batrachochytrium dendrobatidis (Bd), which is responsible for the decline of amphibian species worldwide. By exposing juvenile and adult frogs to the same dose and strain of Bd, we uncovered ontogenetic differences in susceptibility. Froglets exposed to the pathogen had significantly lower survival rates compared with control froglets, while adult frogs largely cleared infection and had survival rates indistinguishable from control frogs, even when exposed to a much higher dose of Bd. The high disease-induced mortality rate of juveniles may explain ongoing population declines in eastern Puerto Rico, where Bd is endemic and juveniles experience higher prevalence and infection intensity compared to adults. Our results have important implications for understanding and modeling the decline, possibly to extinction, of amphibian populations and species.

The Attractiveness Halo Effect and the Babyface Stereotype in Older and Younger Adults: Similarities, Own-Age Accentuation, and Older Adult Positivity Effects

Background/Study Context: Two well-documented phenomena in person perception are the attractiveness halo effect (more positive impressions of more attractive people), and the babyface stereotype (more childlike impressions of more babyfaced people), shown by children, young adults (YA), and people from diverse cultures. This is the first study to systematically investigate these face stereotypes in older adults (OA) and to compare effects for younger and older adult faces.Methods: YA and OA judges rated competence, health, hostility, untrustworthiness, attractiveness, and babyfaceness of older and younger neutral expression faces. Multilevel modeling assessed effects of rater age and face age on appearance stereotypes.Results: Like YA, OA showed both the attractiveness halo effect and the babyface stereotype. However, OA showed weaker effects of attractiveness on impressions of untrustworthiness, and only OA associated higher babyfaceness with greater competence. There also was own-age accentuation, with both OA and YA showing stronger face stereotypes for faces closer to their own age. Age differences in the strength of the stereotypes reflected an OA positivity effect shown in more influence of positive facial qualities on impressions or less influence of negative ones, rather than vice versa.Conclusion: OA own-age biases, previously shown in emotion, age, and identity recognition, and OA positivity effects, previously revealed in attention, memory, and social judgments, also influence age differences in the strength and content of appearance stereotypes. Future research should assess implications of these results for age-related differences in susceptibility to appearance biases that YA have shown in socially significant domains, such as judicial and personnel decisions.

P1-S1.12 Age-specific incidence of chlamydia, gonorrhoea, and trichomoniasis infection in adolescent women

BackgroundAge-specific incidence rates of sexually transmitted infections (STI) with Chlamydia trachomatis (CT), Neisseria gonorrhoeae (GC), and Trichomonas vaginalis (TV) are not well characterised in adolescents and young adult women. In...

Chronic Intermittent Ethanol Exposure in Early Adolescent and Adult Male Rats: Effects on Tolerance, Social Behavior, and Ethanol Intake

Given the prevalence of alcohol use in adolescence, it is important to understand the consequences of chronic ethanol exposure during this critical period in development. The purpose of this study was to assess possible age-related differences in susceptibility to tolerance development to ethanol-induced sedation and withdrawal-related anxiety, as well as voluntary ethanol intake after chronic exposure to relatively high doses of ethanol during adolescence or adulthood. Juvenile/adolescent and adult male Sprague-Dawley rats were assigned to one of five 10-day exposure conditions: chronic ethanol (4 g/kg every 48 hours), chronic saline (equivalent volume every 24 hours), chronic saline/acutely challenged with ethanol (4 g/kg on day 10), nonmanipulated/acutely challenged with ethanol (4 g/kg on day 10), or nonmanipulated. For assessment of tolerance development, duration of the loss of righting reflex (LORR) and blood ethanol concentrations (BECs) upon regaining of righting reflex (RORR) were tested on the first and last ethanol exposure days in the chronic ethanol group, with both saline and nonmanipulated animals likewise challenged on the last exposure day. Withdrawal-induced anxiety was indexed in a social interaction test 24 hours after the last ethanol exposure, with ethanol-naïve chronic saline and nonmanipulated animals serving as controls. Voluntary intake was assessed 48 hours after the chronic exposure period in chronic ethanol, chronic saline and nonmanipulated animals using an 8-day 2 bottle choice, limited-access ethanol intake procedure. In general, adolescent animals showed shorter durations of LORR and higher BECs upon RORR than adults on the first and last ethanol exposure days, regardless of chronic exposure condition. Adults, but not adolescents, developed chronic tolerance to the sedative effects of ethanol, tolerance that appeared to be metabolic in nature. Social deficits were observed after chronic ethanol in both adolescents and adults. Adolescents drank significantly more ethanol than adults on a gram per kilogram basis, with intake uninfluenced by prior ethanol exposure at both ages. Adolescents and adults may differ in their ability and/or propensity to adapt to chronic ethanol exposure, with adults, but not adolescents, developing chronic metabolic tolerance. However, this chronic exposure regimen was sufficient to disrupt baseline levels of social behavior at both ages. Taken together, these results suggest that, despite the age-related differences in tolerance development, adolescents are as susceptible as adults to consequences of chronic ethanol exposure, particularly in terms of disruptions in social behavior. Whether these effects would last into adulthood remains to be determined.

Underlying Medical Conditions and Hospitalization for Pandemic (H1N1) 2009, Japan

To the Editor: Early epidemiologic reports suggested that infection with pandemic (H1N1) 2009 virus most commonly occurred in teenagers and young adults (1). Although this infection appears to have a mild clinical course and the mortality rate has been relatively low in Japan (1.6 deaths/1 million population) (2), the reported number of patients with severe (requiring intubation or admission to an intensive care unit) cases of this disease has been increasing (2). The difference in severity of pandemic (H1N1) 2009 infection may be attributed to differences in underlying medical conditions or to age-related differences in susceptibility. To explore these differences, we investigated the incidence of laboratory-confirmed cases of pandemic (H1N1) 2009 virus infections resulting in hospitalization in Japan and the patients’ age-specific risks for hospitalization associated with underlying medical conditions. During the outbreak in Japan, hospitals, local public health centers, and local governments were required to report hospitalizations associated with pandemic (H1N1) 2009 virus to the Ministry of Health, Labour and Welfare in Japan. Infection was confirmed by PCR at local public health centers. The data for hospitalized patients were integrated through a nationwide surveillance system, the interim National Epidemiologic Surveillance of Infectious Diseases. We collected data on patients who were hospitalized in Japan for pandemic (H1N1) 2009 virus infection from July 28 through December 14, 2009. The number of new cases (incidence) increased in the middle of August and peaked at the end of November (2). We excluded from analysis those patients who had been hospitalized for the purpose of infection containment. Medical conditions were defined as diseases that are risk factors for severe illness associated with seasonal influenza: chronic respiratory diseases, chronic cardiovascular diseases, chronic renal diseases, chronic liver diseases, neurologic diseases, hematologic diseases, diabetes, and immunosuppression caused by treatments or illnesses (including malignant neoplasm) and chronic childhood diseases (3,4). Data on the prevalence of the diseases among the population were obtained from the 2005 National Patient Survey and from population estimates obtained by the Ministry of Internal Affairs and Communications in May 2009. During the surveillance period, 12,702 laboratory-confirmed cases for which the patients required hospitalization were reported; 110 of these patients died (Table). Hospitalization incidence was 10.0 admissions/100,000 persons (overall incidence of hospitalization in the general population in 2005 was 1,462.8 admissions/100,000 persons). Median age of hospitalized patients was 7 years (interquartile range 5–11 years). Of the 10,721 patients for whom type of care was known, 680 (6.4%) were admitted to an intensive care unit. Among 486 hospitalized women 15–44 years of age, only 42 (8.6%) were pregnant; this percentage is small compared with results of studies conducted in other countries (5–7). None of the pregnant women were in critical condition and none died of pandemic (H1N1) 2009 infection during the surveillance period. The overall lower prevalence of pregnant women in Japan (≈0.67% of the total population) compared with that in other countries (8) might account for the low number of pregnant women hospitalized for pandemic (H1N1) 2009 virus in Japan. Table Age-specific incidence and risk for hospitalization with laboratory-confirmed pandemic (H1N1) 2009 virus infection, Japan, July 28–December 14, 2009* Of all 12,702 patients, 4,420 (34.8%) had underlying medical conditions. In terms of age, 1,848 (32.6%) of 5,670 patients 5–9 years of age and 324 (81.0%) of 400 patients >70 years of age had underlying medical conditions. For those with underlying medical conditions, incidence of hospitalization was relatively higher for children than for adults; rates for hospitalized children were 814.1, 573.7, and 219.0 per 100,000 persons for those 5–9, 10–14, and 15–19 years of age, respectively; whereas, the rate for hospitalized adults 60–69 years of age was 6.7/100,000 persons. In all age categories, the incidence of hospitalization for pandemic (H1N1) 2009 virus infection was notably higher for patients with underlying medical conditions than for those without. The attributable risk for medical conditions associated with hospitalization for pandemic (H1N1) 2009 virus infection was highest among patients 5–9 and 10–14 years of age (744.7 and 549.6, respectively), whereas the risk was lowest (6.5) among patients 60–69 years of age. The relative risk associated with underlying medical conditions was comparatively higher for patients in age groups 15–19, 20–29, and 30–39 years (48.4, 54.9, and 48.4, respectively) than among those >70 years of age (17.9). In contrast to seasonal influenza (4), persons <20 years of age had higher risk for hospitalization for pandemic (H1N1) 2009 than did older age groups. Considering our findings regarding the attributable risk for hospitalization, interventions that aim to control pandemic (H1N1) 2009 virus infection among children, especially those with underlying medical conditions, can be considered key for minimizing the strain (financial, staffing, space) on the healthcare system. Our findings justify prioritizing the treatment of children and young adults by vaccination and early prescription of antiviral drugs.

Age‐related differences in susceptibility to cisplatin‐induced renal toxicity

Limited experimental models exist to assess drug toxicity in pediatric populations. We recently reported how a multi-age rat model could be used for pre-clinical studies of comparative drug toxicity in pediatric populations. The objective of this study was to expand the utility of this animal model, which previously demonstrated an age-dependent sensitivity to the classic nephrotoxic compound, gentamicin, to another nephrotoxicant, namely cisplatin (Cis). Sprague-Dawley rats (10, 25, 40 and 80 days old) were injected with a single dose of Cis (0, 1, 3 or 6 mg kg(-1) i.p.). Urine samples were collected prior and up to 72 h after treatment in animals that were >or= 25 days old. Several serum, urinary and 'omic' injury biomarkers as well as renal histopathology lesions were evaluated. Statistically significant changes were noted with different injury biomarkers in different age groups. The order of age-related Cis-induced nephrotoxicity was different than our previous study with gentamicin: 80 > 40 > 10 > 25 day-old vs 10 >or= 80 > 40 > 25-day-old rats, respectively. The increased levels of kidney injury molecule-1 (Kim-1: urinary protein/tissue mRNA) provided evidence of early Cis-induced nephrotoxicity in the most sensitive age group (80 days old). Levels of Kim-1 tissue mRNA and urinary protein were significantly correlated to each other and to the severity of renal histopathology lesions. These data indicate that the multi-age rat model can be used to demonstrate different age-related sensitivities to renal injury using mechanistically distinct nephrotoxicants, which is reflected in measurements of a variety of metabolite, gene transcript and protein biomarkers.

Effect of age on susceptibility to Salmonella Typhimurium infection in C57BL/6 mice

Ageing is associated with a decline in immune function, which predisposes the elderly to a higher incidence of infections. Information on the mechanism of the age-related increase in susceptibility to Salmonella enterica serovar Typhimurium (S. Typhimurium) is limited. In particular, little is known regarding the involvement of the immune response in this age-related change. We employed streptomycin (Sm)-pretreated C57BL/6 mice to develop a mouse model that would demonstrate age-related differences in susceptibility and immune response to S. Typhimurium. In this model, old mice inoculated orally with doses of 3 x 10(8) or 1 x 10(6) c.f.u. S. Typhimurium had significantly greater S. Typhimurium colonization in the ileum, colon, Peyer's patches, spleen and liver than young mice. Old mice had significantly higher weight loss than young mice on days 1 and 2 post-infection. In response to S. Typhimurium infection, old mice failed to increase ex vivo production of IFN-gamma and TNF-alpha in the spleen and mesenteric lymph node cells to the same degree as observed in young mice; this was associated with their inability to maintain the presence of neutrophils and macrophages at a 'youthful' level. These results indicate that Sm-pretreated C57BL/6 old mice are more susceptible to S. Typhimurium infection than young mice, which might be due to impaired IFN-gamma and TNF-alpha production as well as a corresponding change in the number of neutrophils and macrophages in response to S. Typhimurium infection compared to young mice.

Pathology of Highly Pathogenic Avian Influenza Virus (H5N1) Infection in Canada Geese (Branta canadensis); Preliminary Studies

Susceptibility of Canada geese (Branta canadensis) to highly pathogenic avian influenza (HPAI) virus (H5N1) infection was studied by inoculating 10 naïve (antibody-negative) animals (5 adults and 5 juveniles) with A/chicken/Vietnam/14/05 (H5N1) virus. In the adults, 1 of 5 became infected, and 4 of 5 remained normal; in the juvenile group, 5 of 5 became infected. The pathology observed in the affected animals was similar to that reported in natural occurrences. Peripheral and parasympathetic nervous systems were examined and found infected, as well as cerebrospinal fluid-contacting neurons. In some locations with significant virus infection in cells, the expected inflammatory reaction was absent or very mild. Immunohistochemistry was used to locate influenza A virus nucleoprotein in brain, spinal cord, respiratory and digestive systems, pancreas, heart, and peripheral and parasympathetic nervous systems. Further studies are needed to explain age-related differences in susceptibility.

Age Effects on the Perception of Motion Illusions

Anomalous motion illusions represent a popular class of illusions and several studies have made an effort to explain their perception. However, understanding is still inconsistent. Age-related differences in susceptibility to illusory motion may contribute to further clarification of the underlying processing mechanisms. We investigated the effect of age on the perception of four different anomalous motion illusions. The Enigma illusion, the Rotating-Snakes illusion, the Pinna illusion, and the Rotating-Tilted-Lines illusion were tested on a total of one hundred and thirty-nine participants covering an age range from 3 to 82 years. In comparison with young adults, children showed a lower likelihood of perceiving motion in all illusions with the exception of the Rotating-Tilted-Lines illusion. For adult subjects, we found significant age effects in the Rotating-Snakes illusion and the Rotating-Tilted-Lines illusion: occurrence of the illusory effect decreased with age. The other two illusions turned out to be unaffected by aging. Finally, intercorrelations between different motion illusions revealed that only the Pinna illusion and the Rotating-Tilted-Lines illusion correlated significantly with each other. The results confirm that anomalous motion illusions should not be considered as a homogeneous group. Possible links between perceptual data and neurophysiological changes related to age are discussed. Perceptual differences due to age provide the opportunity to improve our understanding of illusory motion and point to specific underlying mechanisms.