Hearing treatment for reducing cognitive decline: Design and methods of the Aging and Cognitive Health Evaluation in Elders randomized controlled trial

INTRODUCTION

Hearing impairment is highly prevalent and independently associated with cognitive decline. The Aging and Cognitive Health Evaluation in Elders study is a multicenter randomized controlled trial to determine efficacy of hearing treatment in reducing cognitive decline in older adults. Clinicaltrials.gov Identifier: NCT03243422.

METHODS

Eight hundred fifty participants without dementia aged 70 to 84 years with mild-to-moderate hearing impairment recruited from four United States field sites and randomized 1:1 to a best-practices hearing intervention or health education control. Primary study outcome is 3-year change in global cognitive function. Secondary outcomes include domain-specific cognitive decline, incident dementia, brain structural changes on magnetic resonance imaging, health-related quality of life, physical and social function, and physical activity.

RESULTS

Trial enrollment began January 4, 2018 and is ongoing.

DISCUSSION

When completed in 2022, Aging and Cognitive Health Evaluation in Elders study should provide definitive evidence of the effect of hearing treatment versus education control on cognitive decline in community-dwelling older adults with mild-to-moderate hearing impairment.

Functional Fc gamma receptor gene polymorphisms and donor-specific antibody-triggered microcirculation inflammation

Fc-dependent effector mechanisms may contribute to antibody-mediated rejection (ABMR), and distinct gene polymorphisms modifying the function of Fc gamma receptors (FcγRs) may influence the capability of donor-specific antibodies (DSAs) to trigger inflammation. To evaluate the relevance of functional FcγR variants in late ABMR, 85 DSA-positive kidney allograft recipients, who were recruited upon antibody screening of 741 prevalent patients, were genotyped for polymorphisms in FcγRIIA (FCGR2A-H/R₁₃₁ ; rs1801274), FcγRIIIA (FCGR3A-V/F₁₅₈ ; rs396991), and FcγRIIIB (FCGR3B-neutrophil antigen 1 ([NA1]/NA2; rs35139848). Individuals with high-affinity FCGR3A-V₁₅₈ alleles (V/V₁₅₈ or V/F₁₅₈ ) showed a higher rate (and extent) of peritubular capillaritis (ptc) in protocol biopsies than homozygous carriers of the lower-affinity allele (ptc score ≥1: 53.6% vs 25.9%; P = .018). Associations were independent of C1q-binding to DSA or capillary C4d. In parallel, there was a trend toward increased macrophage- and injury-repair response-associated transcript subsets. Kidney function over 24 months, however, was not different. In support of a functional role of FcγRIIIA polymorphism, NK92 cells expressing FCGR3A-V₁₅₈ produced >2 times as much interferon gamma upon incubation with HLA antibody-coated cells as those expressing FCGR3A-F₁₅₈ . FcγRIIA and FcγRIIIB polymorphisms were not associated with allograft morphology. Our data suggest that the presence of high-affinity FcγRIIIA variants may favor DSA-triggered microcirculation inflammation.

Comparison of Subjective and Objective Measures of Hearing, Auditory Processing, and Cognition Among Older Adults With and Without Mild Cognitive Impairment

PURPOSE

The aims of the study were to compare the Cognitive Self-Report Questionnaire (CSRQ; Spina, Ruff, & Mahncke, 2006) Hearing and Cognitive subscale ratings among older adults with and without probable mild cognitive impairment (MCI) and to examine whether self-report, as measured by the CSRQ, is associated with objective measures of hearing, auditory processing, and cognition.

METHOD

Data analyses included 97 older adults of ages 61-91 years. Participants completed the CSRQ self-report measure as well as a battery of objective measures, including pure-tone audiometry, degraded speech understanding, temporal processing, and memory.

RESULTS

Older adults with probable MCI rated their cognitive abilities more poorly than those without MCI (p = .002), but ratings of hearing and auditory abilities did not differ between the two groups (p = .912). Age and CSRQ Hearing subscale ratings explained a significant proportion of variance in objective measures of hearing and degraded speech understanding (R2 = .39, p < .001). Age, sex, mental status, and CSRQ Cognition subscale ratings explained a significant proportion of variance in objective memory performance (R2 = .55, p < .001).

CONCLUSIONS

Taken together, these results suggest that the CSRQ is an appropriate self-report measure of hearing, cognition, and some aspects of auditory processing for older adults with and without probable MCI.

Hearing Screening in the Community

BACKGROUND

Adults typically wait 7-10 yr after noticing hearing problems before seeking help, possibly because they are unaware of the extent of their impairment. Hearing screenings, frequently conducted at health fairs, community events, and retirement centers can increase this awareness. To our knowledge, there are no published studies in which testing conditions and outcomes have been examined for multiple "typical screening events."

PURPOSE

The purpose of this article is to report hearing screening outcomes for pure tones and self-report screening tests and to examine their relationship with ambient noise levels in various screening environments.

STUDY SAMPLE

One thousand nine hundred fifty-four individuals who completed a hearing screening at one of 191 community-based screening events that took place in the Portland, OR, and Tampa, FL, metro areas.

DATA COLLECTION AND ANALYSIS

The data were collected during the recruitment phase of a large multisite study. All participants received a hearing screening that consisted of otoscopy, pure-tone screening, and completion of the Hearing Handicap Inventory-Screening Version (HHI-S). In addition, ambient sound pressure levels were measured just before pure-tone testing.

RESULTS

Many more individuals failed the pure-tone screening (n = 1,238) and then failed the HHI-S (n = 796). The percentage of individuals who failed the pure-tone screening increased linearly with age from <20% for ages <45 yr to almost 100% for individuals aged ≥85 yr. On the other hand, the percentage of individuals who failed the HHI-S remained unchanged at approximately 40% for individuals aged ≥55 yr. Ambient noise levels varied considerably across the hearing screening locations. They impacted the pure-tone screen failure rate but not the HHI-S failure rate.

CONCLUSIONS

It is important to select screening locations with a quiet space for pure-tone screening, use headphones with good passive attenuation, measure sound levels regularly during hearing screening events, halt testing if ambient noise levels are high, and/or alert individuals to the possibility of a false-positive screening failure. The data substantiate prior findings that the relationship between pure-tone sensitivity and reported hearing loss changes with age. Although it might be possible to develop age-specific HHI-S failure criteria to adjust for this, such an endeavor is not recommended because perceived difficulties are the best predictor of hearing health behaviors. Instead, it is proposed that a public health focus on education about hearing and hearing loss would be more effective.

Coffee consumption and risk of renal cell carcinoma

BACKGROUND

Studies have suggested an inverse association between coffee consumption and risk of renal cell carcinoma (RCC); however, data regarding decaffeinated coffee are limited.

METHODS

We conducted a case-control study of 669 incident RCC cases and 1,001 frequency-matched controls. Participants completed identical risk factor questionnaires that solicited information about usual coffee consumption habits. The study participants were categorized as non-coffee, caffeinated coffee, decaffeinated coffee, or both caffeinated and decaffeinated coffee drinkers. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression, adjusting for multiple risk factors for RCC.

RESULTS

Compared with no coffee consumption, we found an inverse association between caffeinated coffee consumption and RCC risk (OR 0.74; 95% CI 0.57-0.99), whereas we observed a trend toward increased risk of RCC for consumption of decaffeinated coffee (OR 1.47; 95% CI 0.98-2.19). Decaffeinated coffee consumption was associated also with increased risk of the clear cell RCC (ccRCC) subtype, particularly the aggressive form of ccRCC (OR 1.80; 95% CI 1.01-3.22).

CONCLUSIONS

Consumption of caffeinated coffee is associated with reduced risk of RCC, while decaffeinated coffee consumption is associated with an increase in risk of aggressive ccRCC. Further inquiry is warranted in large prospective studies and should include assessment of dose-response associations.

Evaluation of awareness of risk factors for kidney cancer among patients presenting to a urology clinic

OBJECTIVE

This study aimed to evaluate awareness of risk factors for kidney cancer among patients presenting to a urology clinic. Smoking, obesity and hypertension are widely accepted as risk factors for kidney cancer; however, there are limited data regarding awareness of these risk factors.

MATERIAL AND METHODS

The researchers prospectively identified 172 patients presenting to a urology clinic between 1 May 2009 and 31 August 2009. Each patient completed a questionnaire that requested responses to whether certain lifestyle factors increased the risk of a variety of cancers. Information on demographics and other covariates was collected via questionnaires and medical chart abstraction. To estimate and compare risk factor awareness levels for different cancers, 95% confidence intervals (95% CIs) were constructed and Fisher's exact tests performed. Logistic regression analysis was used to evaluate covariates associated with risk factor awareness.

RESULTS

The percentage reporting that smoking increases the risk of kidney cancer (36%, 95% CI 29-44%) was lower than for lung cancer (96%, 95% CI 92-99%). Similarly, the percentage reporting that obesity increases the risk of kidney cancer (32%, 95% CI 25-40%) was lower than for colon cancer (45%, 95% CI 37-53% CI). Only 18% (95% CI 13-25%) identified hypertension as a risk factor for kidney cancer. Female gender and younger age were associated with increased levels of awareness of the association with smoking and obesity, respectively.

CONCLUSION

The data support a low level of awareness of kidney cancer risk factors and underscore an opportunity for urologists to engage in education efforts.

Abstract A62: Alcohol consumption, genetic variation in alcohol dehydrogenase genes, and risk of clear cell renal cell carcinoma

Introduction: An inverse association between alcohol consumption and risk of renal cell carcinoma (RCC) is well reported in the literature. Despite this, no investigators have explored the potential for effect modification of this association by genetic variations in enzymes that metabolize alcohol. Motivated by this, we conducted a pilot investigation of the role of genetic variation in the alcohol dehydrogenase genes (ADH) as an effect modifier of the association of alcohol and RCC risk.

Methods: We analyzed data on 121 RCC cases and 121 controls. Cases were prospectively collected as part of our Renal Registry in the Department of Urology. Controls were recruited through the Family Medicine and frequency matched to cases on age, gender and state of residence. We collected detailed risk factor data (self-report questionnaire) as well as a DNA sample on cases and controls. We utilized Sequenome analysis to determine presence of published SNPs in the ADH gene cluster (ADH1-7). We employed logistic regression with interaction terms as well as stratified analyses to evaluate effect modification by genetic variants in the ADH gene cluster on the association of alcohol consumption and RCC risk.

Results: Compared to non-drinkers, those that consumed alcohol above the median experienced a lowering in RCC risk (OR=0.80; 95% CI 0.5 to 1.43). We observed evidence of interactions with 6 SNPs in the ADH gene (p-values from 0.05-0.2). As an example, in stratified analysis, the inverse association strengthened in those without the minor allele present at rs1154454 in ADH7 (OR=0.56; 95% CI 0.3 to 1.0; p=0.08) while evidence of an increased in RCC risk was noted among those with the minor allele (OR=2.14; 95CI 0.8 – 5.7; p=0.1). Adjustment for age and gender did not alter our results.

Conclusion: Our pilot data suggest that specific variants in the ADH gene cluster may modify the reported protective effect of alcohol consumption on RCC risk. Given the possible implications for improving our understanding of the biology of this association and informing prevention, future investigations that analyze a larger sample size and examine additional variants are warranted.

Citation Format: Alexander Scott Parker, Nancy Diehl, Michelle L. Arnold, Shauna Rivera, Ashley Cannon, Kaitlynn Custer, Bradley Leibovich. Alcohol consumption, genetic variation in alcohol dehydrogenase genes, and risk of clear cell renal cell carcinoma. [abstract]. In: Proceedings of the Twelfth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2013 Oct 27-30; National Harbor, MD. Philadelphia (PA): AACR; Can Prev Res 2013;6(11 Suppl): Abstract nr A62.

Comparison of baseline quality of life measures between renal cell carcinoma patients undergoing partial versus radical nephrectomy

Background

To compare demographics, pathologic features, performance scores, comorbidities, symptoms and responses to quality of life (QoL) surveys between nephron-sparing surgery (NSS) and radical nephrectomy (RN) patients prior to surgical intervention. Previous investigators have compared QoL outcomes for patients undergoing RN and NSS; however, there are limited data comparing QoL-related characteristics at baseline between these groups.

Methods

We identified 144 patients with localized RCC who underwent either NSS (n = 71) or RN (n = 73) between May ‘07-November ‘12. We abstracted baseline data on demographic and clinic-pathologic variables as well as responses to the SF-36 and FACT-G surveys from our prospective registry. We amended the FACT-G with 8 additional questions designed to address RCC-specific QoL. For comparisons between the two groups, we employed Wilcoxon rank-sum and Fisher's Exact tests where appropriate.

Results

We observed RN patients to have more aggressive pathology. We noted no difference in performance scores between the two groups; however, RN patients were more likely to have higher Charlson scores (p = 0.022) and various symptoms at presentation (all p <0.001). For the QoL surveys, we did not observe differences on the FACT-G; however, we noted evidence of differential scores between the two groups on specific domains of the SF-36 (e.g. Mental Health; p 0.022) and the RCC-specific QoL questions added to the FACT-G.

Conclusions

We report baseline differences between RN and NSS patients on clinico-pathologic as well as QoL-related metrics. As issues of survivorship become increasingly important, our results underscore the need to consider baseline status in evaluations of QoL-related outcomes for patients undergoing surgery for RCC.

Three-dimensional tumour volume and cancer-specific survival for patients undergoing nephrectomy to treat pT1 clear-cell renal cell carcinoma

Study Type - Prognosis (case series) Level of Evidence 4. What's known on the subject? and What does the study add? The positive association of tumour size (largest tumour dimension on pathology review) and risk of RCC progression and survival following nephrectomy is well documented. Moreover, several clinicopathological scoring systems (i.e. nomograms and algorithms) have been developed to predict outcomes for surgically treated RCC patients and each of these includes tumour size as an independent predictor of RCC outcome. There is still the question of whether information on three-dimensional tumour volume (cm(3) ) can provide additional prognostic information, particularly among patients with small pT1 tumours where the range of tumour size is more limited. Our study demonstrates that increasing tumour volume is associated with a greater risk of RCC-specific death in patients with pT1 ccRCC, with a more pronounced association in pT1a tumours specifically. In addition, we observed evidence that tumour volume may provide more accurate prognostic information than tumour size alone in pT1a patients. Tumour volume may add prognostic information specifically in pT1a RCC.

OBJECTIVE

To address whether information on three-dimensional tumour volume can provide additional prognostic information for patients with small, localized renal cell carcinoma (RCC) superior to tumour size alone.

PATIENTS AND METHODS

We identified 955 patients treated with radical nephrectomy or nephron-sparing surgery for unilateral, sporadic, pT1, pN0/NX, M0, non-cystic clear-cell RCC (ccRCC) between 1980 and 2004, including 515 pT1a patients and 440 pT1b patients. • We estimated tumour volume using three tumour dimensions recorded on pathological analysis and the equation for the volume of an ellipsoid [π/6 (length × width × height)]. For tumour size alone, we used the maximum tumour diameter recorded on pathological analysis. • Univariate and multivariable associations with RCC-specific death were evaluated using Cox proportional hazards regression models summarized with hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

Among pT1a patients, the risk of RCC death associated with having a tumour volume above the median (HR = 4.55; 95% CI, 1.30-15.83; P= 0.018) was markedly higher than having a tumour size above the median (HR = 2.55; 95% CI 0.83-7.85; P= 0.10). Comparison of concordance (c) index values further supported the idea that additional prognostic information was provided by tumour volume (c= 0.659) compared with tumour size (c= 0.600) for pT1a patients. • Among pT1b patients, we noted that associations of tumour volume and tumour size with RCC-specific death were similar. • Multivariable adjustment did not alter our findings.

CONCLUSIONS

Tumour volume could provide valuable prognostic information for patients with pT1a ccRCC but not pT1b ccRCC. • Future investigations are needed to confirm this finding, explore other RCC subtypes and evaluate accuracy of tumour volume determination on radiographic imaging for potential patient management before surgery.

Increasing following headway with prompts, goal setting, and feedback in a driving simulator

We evaluated the effects of prompting, goal setting, and feedback on following headway of young drivers in a simulated driving environment and assessed whether changes produced in following headway were associated with reductions in hard braking when drivers were and were not using cell phones. Participants were 4 university students. During baseline, drivers spent half of the time talking on cell phones while driving. At the start of the intervention, drivers were prompted to increase following headway while on the cell phones and were provided a specific target for following headway. Drivers were given feedback on increasing following headway when on cell phones at the end of each session. The intervention package was associated with an increase in following headway and a decrease in hard braking when participants were on and off the cell phones. Cell phone use did not affect any of the measures.

Ribosomal RNA-encoding DNA introgression across a narrow hybrid zone between two subspecies of grasshopper

A ribosomal RNA-encoding DNA (rDNA) cloned sequence, consisting of a 0.8-kilobase fragment from the 26S/nontranscribed spacer region, was used to identify diagnostic restriction enzyme fragments that distinguish the Moreton and Torresian subspecies of the grasshopper Caledia captiva. These restriction fragments were then used to study patterns of rDNA variation across a narrow geographical hybrid zone between the two subspecies. The pattern of rDNA variation that emerged after the analysis of over 250 individuals clearly demonstrates the asymmetrical introgression of the Moreton ribosomal RNA genes into the Torresian subspecies. This asymmetric movement of genetic material occurs even though there exists extreme postmating F(2) and backcross inviability between the two subspecies. From our data, as well as those of previous chromosomal and allozymic studies, we are able to support the occurrence of nonrandom processes such as biased gene conversion and/or natural selection. Because the rDNA loci in the Moreton and Torresian individuals are located in different regions on chromosomes 10 and 11, it should be possible to determine the relative contributions of conversion, natural selection, and these sorts of processes to the pattern of introgression of the Moreton rDNA into the Torresian subspecies.

Dosimetry for Quantitative Analysis of the Effects of Low-Dose Ionizing Radiation in Radiation Therapy Patients

We have developed and validated a practical approach to identifying the location on the skin surface that will receive a prespecified biopsy dose (ranging down to 1 cGy) in support of in vivo biological dosimetry in humans. This represents a significant technical challenge since the sites lie on the patient's surface outside the radiation fields. The PEREGRINE Monte Carlo simulation system was used to model radiation dose delivery, and TLDs were used for validation on phantoms and for confirmation during patient treatment. In the developmental studies, the Monte Carlo simulations consistently underestimated the dose at the biopsy site by approximately 15% (of the local dose) for a realistic treatment configuration, most likely due to lack of detail in the simulation of the linear accelerator outside the main beam line. Using a single, thickness-independent correction factor for the clinical calculations, the average of 36 measurements for the predicted 1-cGy point was 0.985 cGy (standard deviation: 0.110 cGy) despite patient breathing motion and other real-world challenges. Since the 10-cGy point is situated in the region of high-dose gradient at the edge of the field, patient motion had a greater effect, and the six measured points averaged 5.90 cGy (standard deviation: 1.01 cGy), a difference that is equivalent to approximately a 6-mm shift on the patient's surface.

An accelerator based system for in vivo neutron activation analysis measurements of manganese in human hand bones

Manganese (Mn) is an essential nutrient for growth and development. Unfortunately, overexposure can lead to neurological damage, which is manifested as a movement disorder marked by tremors. Preclinical symptoms have been found in populations occupationally exposed to the element, and it is suggested that in late stages of the disorder, removing the Mn exposure will not prevent symptoms from progressing. Hence, it is desirable to have a means of monitoring Mn body burden. In vivo neutron activation analysis (IVNAA) is a technique which allows the concentration of some elements to be determined within sites of the body without invasive procedures. Data in the literature suggests that the Mn concentration in bone is greater than other tissues, and that it may be a long term storage site following exposure. Therefore, using the McMaster KN-accelerator to produce neutrons through the 7Li(p,n)7Be reaction, the feasibility of IVNAA for measuring Mn levels in the human hand bone was investigated. Mn is activated through the 55Mn(n,gamma)56Mn reaction, and the 847 keV gamma rays emitted when 56Mn decays are measured outside the body using NaI(Tl) detectors. An optimal incident proton energy of 2.00 MeV was determined from indium foil and microdosimetry measurements. Hand phantom data suggest a minimum detectable limit of approximately 1.8 ppm could be achieved with a reasonably low dose of 50 mSv to the hand (normal manganese levels in the human hand are approximately 1 ppm). It is recommended the technique be developed further to make human in vivo measurements.

Genetics and the fitness of hybrids

Over the years, the evolutionary importance of natural hybridization has been a contentious issue. At one extreme is the relatively common view of hybridization as an evolutionarily unimportant process. A less common perspective, but one that has gained support over the past decade, is that of hybridization as a relatively widespread and potentially creative evolutionary process. Indeed, studies documenting the production of hybrid genotypes exhibiting a wide range of fitnesses have become increasingly common. In this review, we examine the genetic basis of such variation in hybrid fitness. In particular, we assess the genetic architecture of hybrid inferiority (both sterility and inviability). We then extend our discussion to the genetic basis of increased fitness in certain hybrid genotypes. The available evidence argues that hybrid inferiority is the result of widespread negative epistasis in a hybrid genetic background. In contrast, increased hybrid fitness can be most readily explained through the segregation of additive genetic factors, with epistasis playing a more limited role.

Differential inhibitory effects of intravenous immunoglobulin preparations on HLA-alloantibodies in vitro

BACKGROUND

Treatment of allosensitized patients with intravenously administered pooled immunoglobulin preparations (IVIG) may lead to a long-lasting reduction of anti-HLA alloantibody titers. An inhibitory response of IVIG preparations on lymphocytotoxicity is suggested to depend on IgG and to predict a successful reduction of anti-HLA alloantibodies upon the administration of high-dose IVIG in vivo.

METHODS

In this study, we evaluated different IVIG preparations for their in vitro inhibitory capacity on lymphocytotoxicity and binding of anti-HLA alloantibodies to purified HLA antigens. For that purpose sera from 24 highly sensitized patients awaiting kidney transplantation and serological HLA testing reagents were used. Panel-reactive antibody (PRA) determinations using standard complement-dependent cytotoxicity testing and anti-HLA alloantibody determination by ELISA were carried out in the presence and absence of 50% (v/v) IVIG.

RESULTS

The addition of IgG-containing IVIG preparations gave only a moderate inhibitory response judging from the average decrease of PRA levels (absolute DeltaPRA range: -2% to 16%), whereas the largest inhibition of lymphocytotoxicity was seen after the addition of IgM/IgA-containing IVIG preparations (absolute DeltaPRA range: 19% to 44%). For both IgG and IgM/IgA-containing IVIG preparations, the reduction of lymphocytotoxicity occurred in a dose-dependent fashion without a preference for particular anti-HLA class I antibody specificities. Significantly lower inhibitory effects on anti-HLA antibody reactivity were observed when the effects of IVIG preparations were monitored by ELISA (absolute DeltaPRA range: 7% to 22%).

CONCLUSIONS

Our data suggest that the immunomodulatory capacity is largely caused by the IgM/IgA fraction of IVIG when analyzed by lymphocytotoxicity. The different effect on ELISA versus complement-dependent cytotoxicity testing suggests that interactions of IVIG with complement rather than anti-idiotypic antibodies may contribute to the inhibitory effects of IVIG in vitro.

Intimately linked or hardly speaking? The relationship between genotype and environmental gradients in a Louisiana Iris hybrid population

Several models of hybrid zone evolution predict the same spatial patterns of genotypic distribution whether or not structuring is due to environment-dependent or -independent selection. In this study, we tested for evidence of environment-dependent selection in an Iris fulva x Iris brevicaulis hybrid population by examining the distribution of genotypes in relation to environmental gradients. We selected 201 Louisiana Iris plants from within a known hybrid population (80 m x 80 m) and placed them in four different genotypic classes (I. fulva, I. fulva-like hybrid, I. brevicaulis-like hybrid and I. brevicaulis) based on seven species-specific random amplified polymorphic DNA (RAPD) markers and two chloroplast DNA haplotypes. Environmental variables were then measured. These variables included percentage cover by tree canopy, elevation from the high water mark, soil pH and percentage soil organic matter. Each variable was sampled for all 201 plants. Canonical discriminant analysis (CDA) was used to infer the environmental factors most strongly associated with the different genotypic groups. Slight differences in elevation (-0.5 m to +0.4 m) were important for distinguishing habitat distributions described by CDA, even though there were no statistical differences between mean elevations alone. I. brevicaulis occurred in a broad range of habitats, while I. fulva had a narrower distribution. Of all the possible combinations, I. fulva-like hybrids and I. brevicaulis-like hybrids occurred in the most distinct habitat types relative to one another. Each hybrid class was not significantly different from its closest parent with regard to habitat occupied, but was statistically unique from its more distant parental species. Within the hybrid genotypes, most, but not all, RAPD loci were individually correlated with environmental variables. This study suggests that, at a very fine spatial scale, environment-dependent selection contributed to the genetic structuring of this hybrid zone.

Adult generativity and the socialization of adolescents: relations to mothers' and fathers' parenting beliefs, styles, and practices

Mothers, fathers, and their adolescent children participated in two studies investigating the relations between Erikson's concept of generativityin adulthood and patterns of parenting. Study 1 involved 77 mothers and 48 fathers of 1st-year university students; Study 2 was part of an investigation of socialization processes in 35 families with an adolescent, aged 14-18. Parental generative concern was assessed by the Loyola Generativity Scale (LGS) of McAdams and de St. Aubin (1992) in each study. In both studies, mothers demonstrated positive relations between scores on the LGS and an authoritative style of parenting, as well as between generativity and more positive, optimistic views of adolescent development. In Study 2, these more positive views in turn mediated some aspects of autonomy-fostering practices used with the adolescent. Variations in fathers' levels of generative concern were less consistently related to these indices of parenting, however.

Age-specific fitness components in hybrid females of Drosophila pseudoobscura and D. persimilis

Most models of hybridization assume that hybrids are less fit than their parental taxa. In contrast, some researchers have explored the possibility that hybrid individuals may actually have higher fitness and so play an important role in the generation of new species or adaptations. By estimating age-specific fitness components, we can determine not only how hybrid fitness differs from parental taxa, but also whether the fitness of hybrids relative to parental taxa changes with age. Here we describe an analysis of age-specific fitness traits in two species of Drosophila, D. pseudoobscura and D. persimilis, and their F1 hybrids. At early ages, hybrid females lay as many eggs as parental individuals, on average, but produce far fewer offspring. By late ages, in contrast, parental taxa show a steep decline in production not seen in hybrids, such that hybrids produce more offspring, on average, than parental taxa. Furthermore, egg-adult survival in hybrids is negatively correlated with egg density, whereas these traits are only weakly correlated in parental taxa. The results are limited somewhat by the fact that we analyze only two strains, and that these may be partially inbred. Nonetheless, the results are certainly illustrative, pointing out not only that at least some hybrid individuals may be as fit or fitter than parental taxa, but also that the difference between hybrids and parental taxa varies with age.