Jumping in lantern bugs (Hemiptera, Fulgoridae)

Lantern bugs are amongst the largest of the jumping hemipteran bugs, with body lengths reaching 44 mm and masses reaching 0.7 g. They are up to 600 times heavier than smaller hemipterans that jump powerfully using catapult mechanisms to store energy. Does a similar mechanism also propel jumping in these much larger insects? The jumping performance of two species of lantern bugs (Hemiptera, Auchenorrhyncha, family Fulgoridae) from India and Malaysia was therefore analysed from high-speed videos. The kinematics showed that jumps were propelled by rapid and synchronous movements of both hind legs, with their trochantera moving first. The hind legs were 20–40% longer than the front legs, which was attributable to longer tibiae. It took 5–6 ms to accelerate to take-off velocities reaching 4.65 m s⁻¹ in the best jumps by female Kalidasa lanata. During these jumps, adults experienced an acceleration of 77 g, required an energy expenditure of 4800 μJ and a power output of 900 mW, and exerted a force of 400 mN. The required power output of the thoracic jumping muscles was 21,000 W kg⁻¹, 40 times greater than the maximum active contractile limit of muscle. Such a jumping performance therefore required a power amplification mechanism with energy storage in advance of the movement, as in their smaller relatives. These large lantern bugs are near isometrically scaled-up versions of their smaller relatives, still achieve comparable, if not higher, take-off velocities, and outperform other large jumping insects such as grasshoppers.

Summary: Lantern bugs are large insects that jump at high-take-off velocities using a catapult mechanism that matches the performance of their much smaller planthopper relatives

"I Don't Feel Like I Have a Problem Because I Can Still Go To Work and Function": Problem Recognition Among Persons With Substance Use Disorders

Background: Persons with substance use disorders (SUDs) who do not recognize their substance use as problematic are less likely to perceive needing treatment and less motivated to seek help. Factors that contribute to problem recognition among persons with SUDs are poorly understood. Objective: To explore in-depth factors that may explain why those who meet diagnostic criteria for SUDs do not perceive having a substance abuse problem. Methods: We recruited 54 participants with recent (i.e., past-5-year) SUD for qualitative interviews. Participants were recruited via online ads and screened for eligibility through an online survey. Interview questions focused on participants' alcohol and drug use behaviors, adverse consequences stemming from their substance use, past treatment use experiences, and barriers/reasons for not using specialty treatment. Interviews were thematically coded to identify prominent themes that may explain low problem recognition. Results: We identified two prominent themes that contributed to problem recognition: modifying substance use behaviors to avoid adverse consequences and stigma (i.e., "othering"). Participants who (1) reported adjusting their alcohol and drug use in ways that would not interfere with important life responsibilities, especially work-responsibilities; (2) described those with alcohol and drug problems negatively; and (3) associated treatment with personal defeat were less likely to perceive having a SUD. Conclusions/Importance: These findings can be used to inform intervention strategies aimed at increasing problem recognition among persons with SUDs. Such strategies may facilitate motivation (i.e., desire for help and treatment readiness) to use and complete treatment, thereby reducing the unmet treatment gap among persons with SUDs.

Exploring Jordan's rule in Pacific three-spined stickleback Gasterosteus aculeatus

Coastal marine Gasterosteus aculeatus were captured from seven locations along the Pacific coast of North America, ranging across 21·8° latitude to test Jordan's rule, i.e. that vertebral number should increase with increasing latitude for related populations of fish. Vertebral number significantly increased with increasing latitude for both total and caudal vertebral number. Increasing length with latitude (sensu Bergmann's rule) was also supported, but the predictions for Jordan's rule held when controlling for standard length. Pleomerism was weakly evidenced. Gasterosteus aculeatus exhibited sexual dimorphism for Jordan's rule, with both sexes having more vertebrae at higher latitudes, but only males showing a positive association between latitude and the ratio of caudal to abdominal vertebrae. The number of dorsal- and anal-fin rays and basals increased with increasing latitude, while pectoral-fin ray number decreased. This study reinforces the association between phenotypic variation and environmental variation in marine populations of G. aculeatus.

Correction: Evidence for a surface gold hydride on a nanostructured gold catalyst

Correction for 'Evidence for a surface gold hydride on a nanostructured gold catalyst' by I. P. Silverwood et al., Chem. Commun., 2016, 52, 533-536.

Evidence for a surface gold hydride on a nanostructured gold catalyst

Inelastic neutron scattering and isotopic infrared spectroscopy shows formation of surface Au–H, an important intermediate in catalytic mechanisms.

Genome-wide patterns of divergence during speciation: the lake whitefish case study

The nature, size and distribution of the genomic regions underlying divergence and promoting reproductive isolation remain largely unknown. Here, we summarize ongoing efforts using young (12 000 yr BP) species pairs of lake whitefish (Coregonus clupeaformis) to expand our understanding of the initial genomic patterns of divergence observed during speciation. Our results confirmed the predictions that: (i) on average, phenotypic quantitative trait loci (pQTL) show higher F(ST) values and are more likely to be outliers (and therefore candidates for being targets of divergent selection) than non-pQTL markers; (ii) large islands of divergence rather than small independent regions under selection characterize the early stages of adaptive divergence of lake whitefish; and (iii) there is a general trend towards an increase in terms of numbers and size of genomic regions of divergence from the least (East L.) to the most differentiated species pair (Cliff L.). This is consistent with previous estimates of reproductive isolation between these species pairs being driven by the same selective forces responsible for environment specialization. Altogether, dwarf and normal whitefish species pairs represent a continuum of both morphological and genomic differentiation contributing to ecological speciation. Admittedly, much progress is still required to more finely map and circumscribe genomic islands of speciation. This will be achieved through the use of next generation sequencing data but also through a better quantification of phenotypic traits moulded by selection as organisms adapt to new environmental conditions.

Frozen F1's amidst a masterpiece of nature: new insights into the rare hybrid origin of gynogenesis in the Amazon molly (Poecilia formosa)

All-female 'species' of fish have been shown to be great models in ecological and evolutionary studies because of the insights they can provide into the origin and evolution of asexuality, the ecology of hybrids, associations between genotype and environment, and the maintenance of sex. Gynogenetic organisms that evolved from sexual ancestors, and combine the disadvantageous traits from sexuality and asexuality, have long baffled evolutionary biologists trying to understand their origin and persistence with their sympatric sexual counterparts. In this issue, a new study using an integrated molecular phylogenetic and classical genetic approach has uncovered compelling evidence regarding the obscure asexual origin of the Amazon molly, Poecilia formosa. By performing an extensive phylogeographic analysis, Stöck et al. (2010) provide evidence that the Amazon molly arose only once within its history, with monophyly being strongly supported by mitochondrial DNA and microsatellite analyses. This result, combined with an elaborate failed attempt to resynthesize the lineage, suggests that vertebrate gynogens such as the Amazon molly are not rare because they are at a disadvantage to their sexual counterparts, but because the genomic conditions under which they arise are rare. Organisms that apparently combine the disadvantages of both sexuality and asexuality remain difficult to understand from both an ecological and an evolutionary perspective, and Stöck et al. (2010) highlight several outstanding important questions. Nonetheless, given that we now have a better knowledge of the origin and history of this unique 'species', this should allow researchers to better understand how these frozen F1's can persist amidst the masterpiece of nature.

Ecological predictions lead to the discovery of a benthic–limnetic sympatric species pair of threespine stickleback in Little Quarry Lake, British Columbia

Sympatric species pairs of benthic and limnetic threespine stickleback ( Gasterosteus aculeatus L., 1758 complex) are an important example of the role of ecology in speciation in nature. Four endemic pairs are known and each appears to have diverged independently as a consequence of adaptation to alternative environments. Using specific ecological and physical attributes hypothesized to be important to their evolution, we focused a search for further species pairs. Now, two decades after the last discovery, we describe another benthic–limnetic species pair from Little Quarry Lake on Nelson Island, British Columbia, Canada. Bimodality of genetic admixture values provides evidence of strong reproductive isolation between two morphological and genetic clusters, supporting the existence of a sympatric species pair within this lake. Close correspondence in shape to extant benthic and limnetic species pairs confirm their status as such. The remarkable similarity between them and other benthic and limnetic species pairs in levels of morphological differentiation, as well as extent of admixture and hybridization, points to similar processes underlying their origin. This discovery serves as an important reminder of the specificity of ecological factors that promote and maintain biodiversity, as well as the value of habitat conservation.

Concordance of chlamydia trachomatis infections within sexual partnerships

OBJECTIVES

The enhanced sensitivity of nucleic acid amplification tests (NAAT) provides an opportunity for estimating the prevalence of untreated Chlamydia trachomatis infections. The transmissibility and public health significance of some NAAT-identified infections are, however, not known.

METHODS

Adults attending an urban emergency department provided specimens for C trachomatis screening using NAAT. Participants testing positive were offered follow-up including re-testing for C trachomatis using NAAT and traditional methods, eg culture and direct fluorescent antibody, and were treated. Partners were offered identical evaluation and treatment. Overall, 90 C trachomatis-positive participants had one or more sexual partners enrolled.

RESULTS

Evidence of transmission, as defined by infection concordance between partnerships, was observed among 75% of partners of index cases testing positive by both NAAT and traditional assay but only 45% of partners of index cases testing positive by NAAT only (prevalence ratio 1.7, 95% CI 1.1 to 2.5). Among index participants returning for follow-up, 17% had no evidence of C trachomatis infection by NAAT or traditional assay (median follow-up three weeks).

CONCLUSIONS

A substantial proportion of positive NAAT results for chlamydial infection may be of lower transmissibility and may not persist after a short follow-up. The long-term health effects of some positive NAAT are uncertain.

The Genetic Architecture of Ecological Speciation and the Association with Signatures of Selection in Natural Lake Whitefish (Coregonus sp. Salmonidae) Species Pairs

Adaptive evolutionary change is contingent on variation and selection; thus, understanding adaptive divergence and ultimately speciation requires information on both the genetic basis of adaptive traits as well as an understanding of the role of divergent natural selection on those traits. The lake whitefish (Coregonus clupeaformis) consists of several sympatric "dwarf" (limnetic) and normal (benthic) species pairs that co-inhabit northern postglacial lakes. These young species pairs have evolved independently and display parallelism in life history, behavioral, and morphological divergence associated with the use of distinct trophic resources. We identified phenotype-environment associations and determined the genetic architecture and the role of selection modulating population genetic divergence in sympatric dwarf and normal lake whitefish. The genetic architecture of 9 adaptive traits was analyzed in 2 hybrid backcrosses individually phenotyped throughout their life history. Significant quantitative trait loci (QTL) were associated with swimming behavior (habitat selection and predator avoidance), growth rate, morphology (condition factor and gill rakers), and life history (onset of maturity and fecundity). Genome scans among 4 natural sympatric pairs, using loci segregating in the map, revealed a signature of selection for 24 loci. Loci exhibiting a signature of selection were associated with QTL relative to other regions of the genome more often than expected by chance alone. Two parallel QTL outliers for growth and condition factor exhibited segregation distortion in both mapping families, supporting the hypothesis that adaptive divergence contributing to parallel reductions of gene flow among natural populations may cause genetic incompatibilities. Overall, these findings offer evidence that the genetic architecture of ecological speciation is associated with signatures of selection in nature, providing strong support for the hypothesis that divergent natural selection is currently maintaining adaptive differentiation and promoting ecological speciation in lake whitefish species pairs.

Linkage maps of the dwarf and Normal lake whitefish (Coregonus clupeaformis) species complex and their hybrids reveal the genetic architecture of population divergence

Elucidating the genetic architecture of population divergence may reveal the evolution of reproductive barriers and the genomic regions implicated in the process. We assembled genetic linkage maps for the dwarf and Normal lake whitefish species complex and their hybrids. A total of 877 AFLP loci and 30 microsatellites were positioned. The homology of mapped loci between families supported the existence of 34 linkage groups (of 40n expected) exhibiting 83% colinearity among linked loci between these two families. Classes of AFLP markers were not randomly distributed among linkage groups. Both AFLP and microsatellites exhibited deviations from Mendelian expectations, with 30.4% exhibiting significant segregation distortion across 28 linkage groups of the four linkage maps in both families (P < 0.00001). Eight loci distributed over seven homologous linkage groups were significantly distorted in both families and the level of distortion, when comparing homologous loci of the same phase between families, was correlated (Spearman R = 0.378, P = 0.0021). These results suggest that substantial divergence incurred during allopatric glacial separation and subsequent sympatric ecological specialization has resulted in several genomic regions that are no longer complementary between dwarf and Normal populations issued from different evolutionary glacial lineages.

The genetic basis of intrinsic and extrinsic post-zygotic reproductive isolation jointly promoting speciation in the lake whitefish species complex (Coregonus clupeaformis)

Understanding the genetic architecture of reproductive barriers and the evolutionary forces that drove their divergence represents a considerable challenge towards understanding speciation. The objective of this study was to determine the genetic basis of intrinsic and extrinsic post-zygotic isolation in diverging populations of dwarf and normal lake whitefish with allopatric glacial origins. We found that the rate of embryonic mortality was 5.3-6.5 times higher in dwarf-normal hybrid backcrosses during development than in F1 dwarf and normal crosses. When comparing embryos that died during development against larvae that successfully hatched, patterns of Mendelian segregation at 101 loci whose linkage is known identified 13 loci distributed over seven linkage groups that exhibited significant shifts in segregation ratios leading to significant segregation distortion at these loci in the surviving progeny. Controlled crosses and quantitative trait loci analysis revealed a significant genetic basis for developmental time until emergence, a trait critical to fish larval survival in nature. Hatching backcross progeny exhibited asynchronous emergence and transgressive segregation, suggesting that extrinsic post-zygotic isolation may select against hybridization in specific environmental contexts. Evidence of a genetic basis for increased embryonic mortality followed by asynchronous emergence indicated that intrinsic and extrinsic mechanisms are not mutually exclusive in the formation and maintenance of reproductive isolation, but may be jointly promoting population divergence and ultimately speciation.

Audio computer assisted interviewing to measure HIV risk behaviours in a clinic population

OBJECTIVES

To examine whether audio computer assisted survey interviewing (ACASI) influenced responses to sensitive HIV risk behaviour questions, relative to interviewer administration of those questions (IAQ), among patients attending a sexually transmitted infection (STI) clinic and whether the impact of interview mode on reporting of risk behaviours was homogeneous across subgroups of patients (defined by age, sex, and previous STI clinic experience).

METHODS

1350 clinic patients were assigned to complete a detailed behavioural survey on sexual risk practices, previous STIs and symptoms, condom use, and drug and alcohol use using either ACASI or IAQ.

RESULTS

Respondents assigned to ACASI were more likely to report recent risk behaviours such as sex without a condom in the past 24 hours (adjusted OR = 1.9), anal sex (adjusted OR = 2.0), and one or more new partners in the past 6 months (adjusted OR = 1.5) compared to those interviewed by IAQ. The impact of ACASI varied by sex but, contrary to expectations, not by whether the patient had previously visited an STI clinic. Mode of survey administration made little difference within this population in reports of STI knowledge, previous STIs, STI symptoms, or illicit drug use.

CONCLUSION

ACASI provides a useful tool for improving the quality of behavioural data in clinical environments.

Monitoring STI prevalence using telephone surveys and mailed urine specimens: a pilot test

OBJECTIVES

This pilot test assessed the feasibility of a cost effective population based approach to STI monitoring using automated telephone interviews, urine specimen collection kits sent out and returned by US Postal Service mail, and monetary incentives to motivate participation.

METHODS

100 residents of Baltimore, MD, USA, completed an automated telephone survey and agreed to mail in a urine specimen to be tested for chlamydia and gonorrhoea. Participants were paid dollar 10 for completing the survey and dollar 40 for mailing the specimen.

RESULTS

86% of survey participants mailed in a urine specimen for testing.

CONCLUSIONS

Automated telephone surveys linked with testing of mailed-in urine specimens may be a feasible lower cost (relative to household surveys) method of estimating infection prevalences in a population.

FAST-TRACK: Integrating QTL mapping and genome scans towards the characterization of candidate loci under parallel selection in the lake whitefish (Coregonus clupeaformis)

As natural selection must act on underlying genetic variation, discovering the number and location of loci under the influence of selection is imperative towards understanding adaptive divergence in evolving populations. Studies employing genome scans have hypothesized that the action of divergent selection should reduce gene flow at the genomic locations implicated in adaptation and speciation among natural populations, yet once 'outlier' patterns of variation have been identified the function and role of such loci needs to be confirmed. We integrated adaptive QTL mapping and genomic scans among diverging sympatric pairs of the lake whitefish (Coregonus clupeaformis) species complex in order to test the hypothesis that differentiation between dwarf and normal ecotypes at growth-associated QTL was maintained by directional selection. We found evidence of significantly high levels of molecular divergence among eight growth QTL where two of the strongest candidate loci under the influence of directional selection exhibited parallel reductions of gene flow over multiple populations.

LCR testing for gonorrhoea and chlamydia in population surveys and other screenings of low prevalence populations: coping with decreased positive predictive value

OBJECTIVE

Nucleic acid amplification tests have facilitated field based STD studies and increased screening activities. However, even with highly specific tests, the positive predictive value (PPV) of such tests may be lower than desirable in low prevalence populations. We estimated PPVs for a single LCR test in a population survey in which positive specimens were retested.

METHODS

The Baltimore STD and Behavior Survey (BSBS) was a population based behavioural survey of adults which included collecting urine specimens to assess the prevalence of gonorrhoea and chlamydial infection. Gonorrhoea and chlamydial infection were diagnosed by ligase chain reaction (LCR). Nearly all positive results were retested by LCR. Because of cost considerations, negative results were not confirmed. Predicted curves for the PPV were calculated for a single testing assuming an LCR test sensitivity of 95%, and test specificities in the range 95.0%-99.9%, for disease prevalences between 1% and 10%. Positive specimens were retested to derive empirical estimates of the PPV of a positive result on a single LCR test.

RESULTS

579 participants age 18-35 provided urine specimens. 20 (3.5%) subjects initially tested positive for chlamydial infection, and 39 (6.7%) tested positive for gonococcal infection. If positive results on the repeat LCR are taken as confirmation of a "true" infection, the observed PPV for the first LCR testing was 89.5% for chlamydial infection and 83.3% for gonorrhoea. This is within the range of theoretical PPVs calculated from the assumed sensitivities and specificities of the LCR assays.

CONCLUSIONS

Empirical performance of a single LCR testing approximated the theoretically predicted PPV in this field study. This result demonstrates the need to take account of the lower PPVs obtained when such tests are used in field studies or clinical screening of low prevalence populations. Repeat testing of specimens, preferably with a different assay (for example, polymerase chain reaction), and disclosure of the non-trivial potential for false positive test results would seem appropriate in all such studies.

Combining the analyses of introgressive hybridisation and linkage mapping to investigate the genetic architecture of population divergence in the lake whitefish (Coregonus clupeaformis, Mitchill)

Adaptation and reproductive isolation, the engines of biological diversity, are still elusive when discussing the genetic bases of speciation. Namely, the number of genes and magnitude of selection acting positively or negatively on genomic traits implicated in speciation is contentious. Here, we describe the first steps of an ongoing research program aimed at understanding the genetic bases of population divergence and reproductive isolation in the lake whitefish (Coregonus clupeaformis). A preliminary linkage map originating from a hybrid cross between dwarf and normal ecotypes is presented, whereby some of the segregating AFLP markers were found to be conserved among natural populations. Maximum-likelihood was used to estimate hybrid indices from non-diagnostic markers at 998 AFLP loci. This allowed identification of the most likely candidate loci that have been under the influence of selection during the natural hybridisation of whitefish originating from different glacial races. As some of these loci could be identified on the linkage map, the possibility that selection of traits in natural populations may eventually be correlated to specific chromosomal regions was demonstrated. The future prospects and potential of these approaches to elucidate the genetic bases of adaptation and reproductive isolation among sympatric ecotypes of lake whitefish is discussed.

Parallel somatotopic maps of gustatory and mechanosensory neurons in the central nervous system of an insect

Relatively little is still known about the sense of taste, or contact chemoreception, compared with other sensory modalities, despite its importance to many aspects of animal behaviour. The central projections of the sensory neurons from bimodal contact chemoreceptors (basiconic sensilla) were compared with those from mechanosensory tactile hairs located on similar regions of the middle leg of the locust. Basiconic sensilla are multiply innervated, containing one mechanosensory and several chemosensory neurons, whereas tactile hairs are innervated by a single mechanosensory neuron. We show that the sensory neurons from tactile hairs form a complete 3-dimensional somatotopic map in the mesothoracic ganglion. Sensory neurons from hairs located on the coxa projected to a region near the midline of the ganglion with neurons from hairs located on progressively more distal parts of the leg arborizing in successively more lateral regions of neuropil. All the neurons from basiconic sensilla, both mechanosensory and chemosensory, also projected in a similar, strictly somatotopic, manner, and the arbors from these neurons overlapped considerably with those from tactile hairs on equivalent parts of the leg to form a continuous region. Thus, the position of a receptor on the leg is preserved in the central nervous system not only for the mechanosensory neurons from both tactile hairs and basiconic sensilla but also for chemosensory neurons. We could observe no anatomical features or small differences in projection region between sensory neurons from individual basiconic sensilla consistent with differences in modality.

Local movements evoked by chemical stimulation of the hind leg in the locust Schistocerca gregaria

The behavioural responses of desert locusts, Schistocerca gregaria, to solutions of four behaviourally relevant chemicals (sodium chloride, sucrose, nicotine hydrogen tartrate and lysine glutamate) applied as droplets to the hind tarsus were analysed. All responses following within 1 s of chemical stimulation were local leg avoidance reflexes, and the probability of eliciting such a response increased in a dose-dependent manner with increasing concentration for all the chemicals tested. Chemical identity, however, critically determined the concentration threshold at which the different chemicals became an effective stimulus. For example, a 2.5 mmol l(−)(1) concentration of the secondary plant metabolite nicotine hydrogen tartrate (NHT), a potent feeding deterrent to locusts, was sufficient to evoke avoidance responses in 50 % of cases, whilst for the nutrients, sucrose and lysine glutamate, 250–500 mmol l(−)(1) of the chemical was needed to induce avoidance behaviour in 50 % of the locusts. NaCl was of intermediate effectiveness, with a 50 % response rate occurring at a concentration of approximately 50 mmol l(−)(1). The latency to the start of the response following stimulation was negatively correlated with the concentration of NaCl, but for the other chemicals concentration had no effect on latency. The duration of the avoidance behaviour decreased with increasing concentration for NaCl and more weakly for NHT, but not for the other chemicals. Adding a subthreshold concentration of sucrose to 50 mmol l(−)(1) NaCl decreased the incidence of response compared with 50 mmol l(−)(1) NaCl on its own. Experiments with other mixtures combining NaCl, sucrose and NHT indicate that the frequency and dynamics of the responses to chemical mixtures cannot be simply predicted from the responses to their individual constituents.

Correlates of sexually transmitted bacterial infections among U.S. women in 1995

CONTEXT

Sexually transmitted diseases (STDs) of bacterial origin such as gonorrhea and chlamydial infection can lead to pelvic inflammatory disease (PID) and infertility. Identifying behaviors and characteristics associated with infection may assist in preventing these often asymptomatic diseases and their sequelae.

METHODS

Data from 9,882 sexually active women who participated in the 1995 National Survey of Family Growth describe the characteristics of women who report a history of infection with a bacterial STD or of treatment for PID. Multivariate analysis is used to determine which demographic characteristics and sexual and health-related behaviors affect the likelihood of infection or the occurrence of complications.

RESULTS

Overall, 6% of sexually active women reported a history of a bacterial STD, and 8% reported a history of PID. Women who first had sexual intercourse before age 15 were nearly four times as likely to report a bacterial STD, and more than twice as likely to report PID, as were women who first had sex after age 18. Having more than five lifetime sexual partners also was associated with both having an STD and having PID. PID was more common among women reporting a history of a bacterial STD (23%) than among women who reported no such history (7%). In multivariate analyses, age, race, age at first intercourse and lifetime number of sexual partners had a significant effect on the risk of a bacterial STD. Education, age, a history of IUD use, douching and a history of a bacterial STD had a significant impact on the risk of PID, but early onset of intercourse did not, and lifetime number of partners had only a marginal effect.

CONCLUSIONS

The pattern of characteristics and behaviors that place women at risk of infection with bacterial STDs is not uniform among groups of women. Further, the level of self-reported PID would suggest higher rates of gonorrhea and chlamydial infection than reported.

Effects of interview mode on bias in survey measurements of drug use: do respondent characteristics make a difference?

Three recent empirical studies have provided strong evidence that self-administered questionnaires (SAQs), compared with interviewer questioning, substantially improve the reporting of drug use in population surveys. Specifically, SAQs appear to diminish underreporting bias. Two of these studies previously reported that this effect of interview mode varied significantly across gender, race/ethnicity, and age. Data from a randomized experiment embedded in the 1990 National Household Survey of Drug Abuse (NHSDA) field test were reanalyzed to test for those interaction effects. To better replicate prior studies, the NHSDA field test sample was restricted to people ages 18 to 45 (N = 1,877). The results of our statistical analyses generally replicated the finding of a main effect of SAQs on the reporting of drug use. However, only weak evidence was found to support the hypothesis that the advantage of SAQs varies substantially by the gender, race/ethnicity, or age of the respondent.

Adolescent sexual behavior, drug use, and violence: increased reporting with computer survey technology

Surveys of risk behaviors have been hobbled by their reliance on respondents to report accurately about engaging in behaviors that are highly sensitive and may be illegal. An audio computer-assisted self-interviewing (audio-CASI) technology for measuring those behaviors was tested with 1690 respondents in the 1995 National Survey of Adolescent Males. The respondents were randomly assigned to answer questions using either audio-CASI or a more traditional self-administered questionnaire. Estimates of the prevalence of male-male sex, injection drug use, and sexual contact with intravenous drug users were higher by factors of 3 or more when audio-CASI was used. Increased reporting was also found for several other risk behaviors.

Thermoregulation during exercise in women who are taking oral contraceptives

Thermoregulation during exercise was studied in seven women who were taking oral contraceptive pills for 3 weeks of each month. The subjects were studied once in the 3rd week of taking the pill (P) and once during the following week when they took no pil (N). Rectal temperature (Tre), heart rate (fc) and evaporative water loss (EWL, ventilated capsule technique) were measured while they walked on a treadmill for 60 min at 4.8 km.h-1 at a 10% gradient. Ambient temperature was 22 degrees C. A venous blood sample was drawn 30 min before each experiment for measurement of hematocrit (packed cell volume, PCV), plasma osmolality (Osmpl), and plasma levels of the endogenous pyrogens interleukin-1 beta (IL-1 beta) and interleukin-6 (IL-6). Resting Tre was 0.31 degree C higher in P than in N (P < 0.01) and Tre remained higher in P throughout the entire exercise period (P < 0.01). Threshold Tre for the onset of EWL was 0.32 degree C higher in P than in N (P < 0.01). Exercise fc was 6.5 beats.min-1 higher in P than in N (P < 0.01). There was no significant difference in PCV, Osmpl, IL-1 beta or IL-6 between P and N. It was concluded that the administration of synthetic progestins in oral contraceptives causes an upward shift in the threshold for heat loss responses, resulting in higher body core temperatures both at rest and during exercise. There was no evidence that these alterations in thermoregulation were mediated by changes in body fluid balance or in plasma levels of IL-1 beta or IL-6.

Sexual behavior in the United States 1930-1990: trends and methodological problems

BACKGROUND AND OBJECTIVES

Arguments for population-based research on patterns of sexual behavior are reviewed, and survey data are used to illustrate the insights that can be gained from such research.

STUDY DESIGN

Reports of sexual behavior obtained in surveys of large probability samples of the U.S. population are analyzed and compared to make inferences about changes in the age of onset of sexual intercourse and the patterns of heterosexual and same-gender sexual behaviors of American men and women who entered adulthood during the period from 1930 to 1990.

RESULTS

Strong trends are documented for both a decline in the reported age at first heterosexual intercourse and an increase in the numbers of heterosexual partners reported during adulthood. Similar evidence on patterns of same-gender contact indicate a relatively stable prevalence of reported male-male contact for cohorts of men born from the 1930s through the 1960s. Preliminary analyses suggest, however, that there has been a substantial increase in the proportion of women reporting female-female sexual contact during adulthood. Although the analyses require refinement, it appears that the prevalence of reported female-female contact may have increased by a factor of 3 to 4 for cohorts of women born between the 1930s and the 1960s.

CONCLUSIONS

Although the trends in reported behaviors are robust, inferences about behavior, pre se, rest on the assumption that reporting biases were equivalent across cohorts. Methodological challenges in the interpretation of such findings and new technologies for conducting such research are described.

Neurologic health outcomes and Agent Orange: Institute of Medicine report

The National Academy of Sciences' Institute of Medicine conducted an independent scientific investigation to evaluate the strength of evidence for human health effects among veterans exposed to herbicides used in Vietnam and to suggest future research recommendations. Neurologic domains where multiple studies had been performed in military, occupational, or environmental situations were (1) cognitive and neuropsychiatric effects, (2) motor/coordination dysfunction and other central nervous system disorders, and (3) peripheral neuropathy. In all categories, no strong evidence established an association between herbicides used in Vietnam and clinical neurologic disorders. Methodologic weaknesses, long durations between exposure and assessments, and poor exposure measures limited many studies. The committee concluded that the available evidence was insufficient to determine an association between neurologic disorders and exposure to herbicides used in Vietnam. Neurotoxicologic studies available did not suggest strong biological plausibility for neurologic alterations related to herbicide exposure. Furthermore, given the large uncertainties in the epidemiologic studies reviewed and inadequate control for important confounders, the committee could not quantify a degree of risk for neurologic disorders from herbicide exposure likely to be experienced by Vietnam veterans. Although not part of the neurologic report, the risk of brain tumors was considered in the cancer analysis, and the committee concluded that there is limited/suggestive evidence of no association between exposure to herbicides and brain tumors.

Eye banking: the Minnesota experience

We present a brief report on the activities of the Minnesota Lions Eye Bank. This eye bank receives and supplies tissue to several midwestern states. In addition, it plays a vital role in providing tissue for research and training at the University of Minnesota. In association with the Department of Ophthalmology, the eye bank is also actively involved in the research and development of various corneal preservation systems. Included below is information relative to procedures used in the eye bank for the selection and collection of donor material; the decontamination, preparation, and storage of corneas; cost of eye bank services; and staff coverage. Also included is some data on the number of eyes received and processed and the eventual uses of the tissues, during the last ten years.

Fluorescence characteristics of photoautotrophic soybean cells

We report here the first measurements on chlorophyll (Chl) a fluorescence characteristics of photoautotrophic soybean cells (cell lines SB-P and SBI-P). The cell fluorescence is free from severe distortion problems encountered in higher plant leaves. Chl a fluorescence spectra at 77 K show, after correction for the spectral sensitivity of the photomultiplier and the emission monochromator, peaks at 688, 696 and 745 nm, representing antenna systems of photosystem II-CP43 and CP47, and photosystem I, respectively. Calculations, based on the complementary area over the Chl a fluorescence induction curve, indicated a ratio of 6 of the mobile plastoquinone (including QB) to the primary stable electron acceptor, the bound plastoquinone QA. A ratio of one between the secondary stable electron acceptor, bound plastoquinone QB, and its reduced form QB (-) was obtained by using a double flash technique. Owing to this ratio, the flash number dependence of the Chl a fluorescence showed a distinct period of four, implying a close relationship to the 'S' state of the oxygen evolution mechanism. Analysis of the QA (-) reoxidation kinetics showed (1) the halftime of each of the major decay components (∼ 300 μs fast and ∼ 30 ms slow) increases with the increase of diuron and atrazine concentrations; and (2) the amplitudes of the fast and the slow components change in a complementary fashion, the fast component disappearing at high concentrations of the inhibitors. This implies that the inhibitors used are able to totally displace QB. In intact soybean cells, the relative amplitude of the 30 ms to 300 μs component is higher (40:60) than that in spinach chloroplasts (30:70), implying a larger contribution of the centers with unbound QB. SB-P and SBI-P soybean cells display a slightly different sensitivity of QA (-) decay to inhibitors.

Emergency presentation of coalescent mastoiditis

Since the introduction of sulfonamides in the late 1930s, coalescent mastoiditis is an uncommon complication of otitis media. Swelling, erythema, and tenderness over the mastoid area with associated anterior displacement of the auricle are classic signs and symptoms of coalescent mastoiditis with formation of a subperiosteal abscess. Early recognition of this entity is essential to prevent its complications. Prompt otolaryngologic consultation is indicated and inpatient antibiotic therapy should be begun. Surgical treatment is also needed and may obviate further complications.

Characteristics of Five New Photoautotrophic Suspension Cultures Including Two Amaranthus Species and a Cotton Strain Growing on Ambient CO(2) Levels

Suspension cultures of cotton (Gossypium hirsutum), Amaranthus cruentus, A. powellii, Datura innoxia, and a Nicotiana tabacum-N. glutinosa fusion hybrid were adapted to grow photoautotrophically under continuous light. The cotton strain grew with an atmosphere of ambient CO(2) (about 0.06 to 0.07% in the culture room) while the other strains required elevated CO(2) levels (5%). Photoautotrophy was indicated by the requirement for CO(2) and for light for growth. The strains grew with doubling times near 14 days and had from 50 to 600 micrograms of chlorophyll per gram of fresh weight. The cells grew in small to moderate sized clumps with cell sizes from 40 to 70 micrometers (diameter). Like most photoautotrophic cultures described so far the ribulose 1,5-bisphosphate carboxylase (RuBPcase) activity levels were well below those of mature leaves. The phosphoenolpyruvate carboxylase levels were not elevated in the C(4)Amaranthus species. The cells showed high dark respiration rates and had lower net CO(2) fixation under high O(2) conditions. Dark CO(2) fixation rates ranged from near 10 to 30% of that in light. Fluorescence emission spectra measurements show that the cell antenna pigments systems of the four strains examined are similar to that of chloroplasts of green plants. The cotton strain which was capable of growth under ambient CO(2) conditions showed the unique properties of a high RuBPcase activation level in ambient CO(2) and a stable ability to show net CO(2) fixation in 21% O(2) conditions.

A comparison of two cause-of-death classification systems for deaths among women of reproductive age in Menoufia, Egypt

Mortality data ascertained from sources other than a death registration system can validate the accuracy of the system, but this information is rarely obtained. Data on 1979 deaths among reproductive age women were collected in the 1981-1983 Reproductive Age Mortality Survey (RAMOS) in the governorate of Menoufia, Egypt, and compared with data on these deaths as recorded by the Egyptian death registration system. Although the distribution of the causes of death were similar, there were substantial differences between classification systems for deaths due to particular causes. Over half of the deaths classified differently by the systems were those assigned to circulatory disease on the death certificate. In contrast, there was a high rate of agreement between systems in the classification of trauma deaths. About half (52.4%) of cancer deaths had the same site-specific cancer diagnosis assigned by RAMOS. The percentage of deaths assigned to maternal causes was three times higher in RAMOS (19.2%) than on death certificates (6.1%). Reported mortality rates for this often-preventable cause of death have been substantially underestimated in national death registration systems. Such underreporting masks the need for additional prenatal care and maternal health programmes.

Review: first-pass metabolism by the gastrointestinal mucosa

The bioavailability of orally administered drugs may be reduced due to presystemic elimination. The first-pass effect can occur in the gastrointestinal tract, the liver and lung. Although the liver is the main drug metabolizing organ in the body, the gut wall can play an important role in the first-pass metabolism of certain drugs. Both phase I (preconjugation) and phase II (conjugation) reactions have been described. However, while the oxidative metabolic capacity of the intestinal mucosa is considerably smaller than that of the liver, the activity of conjugation reactions in the gut may be close to that of the liver, and in some cases may exceed it. Sulphate conjugation is particularly important for steriod hormones such as ethinyloestradiol, and for the beta-adrenoceptor stimulants isoprenaline and isoetharine. Glucuronidation has been demonstrated to occur in man for morphine, paracetamol and oestrogens. Significant drug--drug interactions have been described involving drugs undergoing sulphate conjugation. The study of intestinal metabolism in vivo is difficult in man since direct methods (for example, hepatic portal vein catheterization) is justified in only a small number of patients. Therefore, much of our present understanding has been derived from various in-vitro studies involving intestinal sheets, mucosal biopsies, isolated enterocytes and microsomal preparations.

Photosynthetic characteristics of a photoautotrophic cell suspension culture of soybean

A soybean suspension culture (SB-P) which can grow photoautotrophically in 5% CO(2) will not grow in ambient CO(2) levels. This elevated CO(2) requirement seems to be due to the additive effects of a number of factors. The in vivo activity of ribulose-1,5-bisphosphate carboxylase (RuBPcase) is much lower in the SB-P cells, compared to soybean plants. This may be due to the low light intensity used to culture the cells, which has been shown to decrease both the amount and activity in whole plants, resulting in a low rate of net photosynthesis. The RuBPcase activation level is also lowered in air CO(2) levels. The presence of the liquid medium raises the cells CO(2) compensation concentration (the CO(2) concentration reached when the rates of CO(2) fixed by photosynthesis and the CO(2) respired by the cells are equal). These factors, coupled with the high respiratory loss of CO(2) all contribute to reduced net photosynthesis in air, resulting in a photosynthetic capacity that is inadequate for cell survival. Active cell division, low photosynthetic capacity, elevated respiration, and a low ratio of RuBPcase(initial)/phosphoenolpyruvate carboxylase are traits that SB-P cells share with young leaf cells, indicating SB-P cell physiology may be comparable to that of young expanding leaves rather than to that of mature leaves.

Paracetamol interaction with oral contraceptive steroids: increased plasma concentrations of ethinyloestradiol

The effect of a single dose of paracetamol (1 g) on plasma concentrations of the oral contraceptive steroids ethinyloestradiol (EE2) and levonorgestrel (LNG) has been studied in six healthy female volunteers. The area under the plasma concentration-time curve (AUC0-24) of EE2 was significantly increased following paracetamol administration by 22% (control 2221 +/- 291; following paracetamol, 2702 +/- 452 pg ml-1 h; mean +/- s.d.; P less than or equal to 0.05). The greatest effect was evident in the time period 0-3 h. There was a significant decrease in the AUC of EE2-sulphate after paracetamol (7736 +/- 3791 pg ml-1 h) compared with control (13161 +/- 4535 pg ml-1 h; P less than or equal to 0.05). Plasma concentrations of LNG were unaltered by concurrent paracetamol administration. We conclude that the administration of a single 1 g dose of paracetamol causes an increase in plasma concentrations of EE2 as a result of a reduction in the sulphation of the steroid. This interaction may be of clinical significance in women on oral contraceptive steroids who regularly take paracetamol.

Intestinal metabolism of ethinyloestradiol and paracetamol in vitro: studies using Ussing chambers

The intestinal mucosal metabolism of ethinyloestradiol (EE2) and paracetamol (P) has been studied in vitro in Ussing chambers. Histologically normal jejunum or ileum was obtained from 19 patients undergoing various resections. The muscularis externa was stripped off the mucosa and the mucosal sheets mounted between two perspex chambers. Tissue viability was routinely assessed by measurement of the transmural potential difference. The percentage of steroid in the serosal chamber, 2 h after addition of EE2 (2 microCi; 80 ng) to the mucosal chamber was 2.3 +/- 0.8% (mean +/- s.d.) which comprised unconjugated drug (0.4 +/- 0.3%), sulphate conjugates (0.7 +/- 0.5%) and glucuronides (0.9 +/- 0.8%). In the mucosal chamber, 56.6 +/- 11.4% was unconjugated steroid, 33.3 +/- 12.4% sulphate conjugates and 2.1 +/- 2.3% glucuronides. Small amounts of the oxidation products 2-hydroxy and 16-hydroxy-EE2 were present. At 2 h, the percentage of paracetamol in the serosal chamber was 3.2 +/- 1.4% (of added P; 2 microCi; 50 ng) of which 0.5 +/- 0.3% was paracetamol sulphate (PS) and 0.1% was paracetamol glucuronide (PG). In the mucosal chamber 2.4 +/- 0.8% and 1.0 +/- 0.2% was present as PS and PG respectively. The total amount of paracetamol conjugated was approximately 4.0%. When paracetamol in the mucosal chamber was increased to 50 micrograms (i.e. by a factor of 1000) there was a decrease in the percentage of added drug metabolized to PS and an increase in formation of PG. The glucuronide:sulphate ratio was increased from 0.34 to 3.56. Competition for sulphation was evident when both paracetamol and EE2 were presented to the intestinal mucosa.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetics of contraceptive steroids in patients with cystic fibrosis

The pharmacokinetics of the commonly used contraceptive steroids ethinyloestradiol and levonorgestrel were investigated after oral and intravenous administration in six women with cystic fibrosis. The results were compared with data obtained from healthy women of similar age. The total body clearance of ethinyloestradiol was significantly higher in the patients with cystic fibrosis (0.61 (SD 0.19) l/h/kg) than in control women (0.32 (0.16) l/h/kg; p less than 0.02). In addition, the oral bioavailability of ethinyloestradiol was greater in women with cystic fibrosis than in controls (76.9% (11.7%) compared with 47.3% (7.5%); p less than 0.001). As a result of these two changes, the area under the plasma concentration--time curve after an oral dose of ethinyloestradiol was similar in patients and controls. The pharmacokinetics of levonorgestrel did not differ significantly between patients with cystic fibrosis and healthy women. The data suggest that women with cystic fibrosis will receive similar contraceptive protection from these steroids as do healthy women.

Accidental burn deaths to Egyptian women of reproductive age

Among women of reproductive age in Menoufia, Egypt, deaths from burns constitute a major public health problem. Burns account for 9 per cent of the deaths occurring to women aged 15-49, and were the third cause of death (after disease of the circulatory system and complications of pregnancy and childbirth). Nearly two-thirds of the burns were caused by kerosene cooking stoves. The data were obtained from a population-based survey of all deaths to women of reproductive age. There were 1691 deaths from all causes during the 3 years of the study, 152 of these were due to burns. Information on the cause of death was gathered from interviews with surviving family members; interviews were reviewed by physicians and a cause of death established. Although hospital-based studies provide valuable information for the management of burn injuries presenting for treatment, establishing rates of injury, comparing the incidence in one population group relative to another, or comparing the incidence of burns relative to other forms of injury requires a population-based study.

Reproductive mortality in two developing countries

Reproductive mortality includes mortality attributable to pregnancy, termination of pregnancy, childbirth and its sequelae, and contraception. Reproductive mortality has been estimated for the United Kingdom, the United States, and for states of the US. However, it has not previously been measured for developing countries, where maternal mortality often remains distressingly high. This paper reports on data from one governorate of Egypt, where reproductive mortality was 46 per 100,000 married women ages 15-49 (2.2 per cent of this was attributable to contraception), and one province of Indonesia, where reproductive mortality was 70 per 100,000 (of which 1.4 per cent was due to contraception). In both locations, complications of pregnancy and childbirth were a leading cause of death in the age group studied (the first cause in Indonesia, second in Egypt). Contraceptive prevalence was 24 per cent of married women ages 15-49 in Egypt and 48 per cent of this age group in Indonesia.

Early symptoms and discontinuation among users of oral contraceptives in Sri Lanka

The relationship between symptoms reported during the first two cycles of oral contraceptive use and subsequent discontinuation was studied using data from a comparative clinical trial of two oral contraceptives (standard dose and low dose) in Sri Lanka. Among 24 symptoms considered, the most commonly reported were headache, nausea, irritability, dizziness, tiredness, intermenstrual spotting/bleeding, backache, abdominal pain, vomiting, and hair loss. Headache, nausea, vomiting, and dizziness were closely associated with each other and strongly predictive of discontinuation for both drugs. No other symptoms were consistently associated with each other or with subsequent discontinuation. Intermenstrual spotting/bleeding was associated with later discontinuation of the standard dose preparation, but not the lower dose preparation.

IUD--related uterine perforation: an epidemiologic analysis of a rare event using an international dataset

An international dataset of 21,610 IUD insertions revealed 41 uterine perforations occurring at the time of, or subsequent to, insertion. Dat were collected on standard forms. Perforations were classified as confirmed, probable, or possible, based on the clinician's judgement and subsequent management. The uterine perforation rate was estimated as between 1.9 and 3.6/1000 insertions. 13 of the total 41 perforations were reported from 2 of 72 cooperating clinics. In 1 clinic, this center-clustering phenomenon suggested an effect of a high risk device. In the other clinic, the effect of insertor (operator) inexperience was indicated. A case-control analysis delineated previous cesarean section as a host risk factor (P0.05, McNemar's chi square). Further investigation of this association by similar case-control studies is recommended.

Effect of ribosomal wash factors on inhibition by chloramphenicol

In vitro protein-synthesizing systems from Escherichia coli can be categorized as either chloramphenicol-sensitive or chloramphenicol-insensitive. The chloramphenicol-sensitive systems used in this study required the presence of factors removed from ribosomes with 1.0 m NH(4)Cl when chromatographically purified ribosomes were used for amino acid incorporation. These ribosomal wash factors inhibited but did not eliminate amino acid incorporation in chloramphenicol-insensitive systems. For both systems, addition of increasing amounts of the ribosomal wash factors increased the sensitivity to chloramphenicol inhibition.