Multi-ancestry genome-wide association study of kidney cancer identifies 63 susceptibility regions

Here, in a multi-ancestry genome-wide association study meta-analysis of kidney cancer (29,020 cases and 835,670 controls), we identified 63 susceptibility regions (50 novel) containing 108 independent risk loci. In analyses stratified by subtype, 52 regions (78 loci) were associated with clear cell renal cell carcinoma (RCC) and 6 regions (7 loci) with papillary RCC. Notably, we report a variant common in African ancestry individuals ( rs7629500 ) in the 3' untranslated region of VHL, nearly tripling clear cell RCC risk (odds ratio 2.72, 95% confidence interval 2.23-3.30). In cis-expression quantitative trait locus analyses, 48 variants from 34 regions point toward 83 candidate genes. Enrichment of hypoxia-inducible factor-binding sites underscores the importance of hypoxia-related mechanisms in kidney cancer. Our results advance understanding of the genetic architecture of kidney cancer, provide clues for functional investigation and enable generation of a validated polygenic risk score with an estimated area under the curve of 0.65 (0.74 including risk factors) among European ancestry individuals.

Healthcare Provider's Perceived Self-Efficacy in HPV Vaccination Hesitancy Counseling and HPV Vaccination Acceptance

BACKGROUND

HPV vaccine hesitancy is a key contributor to the sub-optimal HPV vaccination uptake in the United States. We aimed to determine the association between healthcare providers' self-efficacy in HPV vaccination hesitancy counseling and HPV vaccination acceptance after initial and follow-up counseling sessions.

METHODS

Population-based cross-sectional study of healthcare providers (HCPs) practicing in Texas. Logistic regression analyses were used to determine the odds of HPV vaccination acceptance by vaccine-hesitant patients. Additionally, generalized estimating equations were used to compare HPV vaccination acceptance by hesitant patients after follow-up versus initial counseling sessions.

RESULTS

1283 HCPs completed the survey with a mean (SD) age of 47.1 (11.3) years. HCPs who believed that they were very/completely confident in counseling HPV-vaccine-hesitant parents had higher odds of observing HPV vaccination acceptance very often/always after an initial counseling session (adjusted odds ratio (AOR): 3.50; 95% CI: 2.25-5.44) and after follow-up counseling sessions (AOR: 2.58; 95% CI: 1.66-4.00) compared to HCPs that perceived they were not at all/somewhat/moderately confident. The odds of HPV vaccination being accepted very often/always by vaccine-hesitant parents was 61% (AOR: 1.61; 95% CI: 1.32-1.95) higher after follow-up counseling sessions compared to an initial counseling session. The results were similar for the counseling of HPV-vaccine-hesitant adult patients.

CONCLUSIONS

The confidence level of HCPs in counseling hesitant parents and adult patients impacts HPV vaccination acceptance. Importantly, acceptance was higher after follow-up counseling sessions than initial counseling sessions. HCPs should receive training in HPV vaccination counseling to enhance their confidence in counseling hesitant patients and should utilize every visit to counsel hesitant patients.

HPV Vaccination Training of Healthcare Providers and Perceived Self-Efficacy in HPV Vaccine-Hesitancy Counseling

HPV vaccine hesitancy is a key barrier to HPV vaccination. Using a population-based survey of HCPs practicing in Texas we determined the association between formal training of HCPs and perceived self-efficacy in counseling HPV vaccine-hesitant parents and adult patients. A total of 1283 HCPs completed the survey, with 879 providing vaccination services to pediatric patients and 1018 providing vaccination services to adult patients. Among HCPs included in this study, 405 of 577 (70%) and 315 of 505 (62%) perceived they were very/completely confident in counseling HPV vaccine-hesitant parents and adult patients, respectively. Compared to HCPs who received no training, those who received formal training in HPV vaccination promotion or counseling had 2.56 (AOR: 2.56; 95% CI:1.69-3.86) and 2.84 times higher odds (AOR: 2.84; 95% CI:1.87-4.33) of perceiving that they were very/completely confident in counseling HPV vaccine-hesitant parents and adult patients, respectively. Additionally, increasing years of practice and volume of patients seen were positively associated with being very/completely confident in counseling HPV vaccine-hesitant parents and adult patients. On the other hand, nurses were less likely than physicians to be very/completely confident in counseling HPV vaccine-hesitant parents. To increase HPV vaccination uptake, HCPs should receive tailored training to improve their self-efficacy in addressing HPV vaccine-hesitancy.

Subpolar North Atlantic western boundary density anomalies and the Meridional Overturning Circulation

Changes in the Atlantic Meridional Overturning Circulation, which have the potential to drive societally-important climate impacts, have traditionally been linked to the strength of deep water formation in the subpolar North Atlantic. Yet there is neither clear observational evidence nor agreement among models about how changes in deep water formation influence overturning. Here, we use data from a trans-basin mooring array (OSNAP-Overturning in the Subpolar North Atlantic Program) to show that winter convection during 2014-2018 in the interior basin had minimal impact on density changes in the deep western boundary currents in the subpolar basins. Contrary to previous modeling studies, we find no discernable relationship between western boundary changes and subpolar overturning variability over the observational time scales. Our results require a reconsideration of the notion of deep western boundary changes representing overturning characteristics, with implications for constraining the source of overturning variability within and downstream of the subpolar region.

Factors Influencing Discussion of Cancer Genetic Testing with Health-Care Providers in a Population-Based Survey

INTRODUCTION

Discussion of cancer genetic testing with health-care providers (HCPs) is necessary to undergo testing to inform cancer risk assessment and prevention. Given the rapid evolution in genetic testing practice in oncology, we describe the current landscape of population-level cancer genetic testing behaviors.

METHODS

A questionnaire including items regarding discussion of cancer genetic testing with HCPs was administered to a nonprobability sample (N = 2,029) of the Texas population.

RESULTS

Overall, 11% of respondents discussed cancer genetic testing with HCPs. In multivariable analysis, discussion was significantly related to having a personal history of breast/ovarian/colon cancer (OR = 11.57, 95% CI = 5.34-25.03), personal history of other cancer (OR = 3.18, 95% CI = 1.69-5.97), and health information-seeking behaviors (OR = 1.73, 95% CI = 1.12-2.66). Surprisingly, respondents who believed that inherited predispositions in addition to other modifiable risk factors cause cancer were less likely to discuss genetic testing compared to those who did not believe that inherited cancer predispositions cause cancer (OR = 0.54, 95% CI = 0.36-0.79).

DISCUSSION

The high discussion rate may be attributed to increased public awareness of genetic testing and adoption of more inclusive clinical genetic testing guidelines. The findings suggest that efforts to increase public awareness of the utility of genetic testing on personalized cancer risk assessment and cancer prevention are needed.

Reasons for not receiving the HPV vaccine among eligible adults: Lack of knowledge and of provider recommendations contribute more than safety and insurance concerns

Background

The upward trends of vaccine exemptions in Texas are alarming. While HPV vaccine rates in this State are among the lowest nationwide, factors that contribute to the low HPV vaccination uptake among adults remain unknown. In this study, we examined the main reasons for not receiving HPV vaccination among age‐eligible adults.

Methods

The Texas health screening survey (2018), a multistage area probability design‐based survey of a representative sample of Texas residents, was used to identify 907 eligible adults (age ≥ 18 years) respondents, including 724 women aged ≤ 26 years in 2007 (≤38 years in 2018), and 183 men aged ≤ 21 years in 2011 (≤28 years in 2018). Participants who reported having never received an HPV shot, where asked the main reason for not receiving the vaccine.

Results

Overall, 58.5% (95%CI: 55.1‐62.0) of vaccine eligible adults reported having never received the HPV vaccine. The most commonly reported reasons for not receiving it were: did not know about the vaccine (18.5% (14.9‐22.1)), and provider did not recommend (14.1% (10.9‐17.4)). In contrast, commonly perceived reasons such as: safety concerns (7.2% (4.8‐9.5)), lack of insurance (3.4% (1.7‐5.1), and concerns about increasing sexual activity if vaccinated (0.2% (0.0‐0.5)), were less frequently reported.

Conclusion

Among vaccine‐eligible adults, safety and sexuality concerns do not appear to be the prime factors underlying low HPV vaccination rates. Rather than emphasizing them, educational interventions should aim at improving vaccine's knowledge, and enhancing provider recommendations on the necessity of HPV vaccination.

Non-Bee Insects as Visitors and Pollinators of Crops: Biology, Ecology, and Management

Insects other than bees (i.e., non-bees) have been acknowledged as important crop pollinators, but our understanding of which crop plants they visit and how effective they are as crop pollinators is limited. To compare visitation and efficiency of crop-pollinating bees and non-bees at a global scale, we review the literature published from 1950 to 2018 concerning the visitors and pollinators of 105 global food crops that are known to benefit from animal pollinators. Of the 105 animal-pollinated crops, a significant proportion are visited by both bee and non-bee taxa (n = 82; 77%), with a total gross domestic product (GDP) value of US$780.8 billion. For crops with a narrower range of visitors, those that favor non-bees (n = 8) have a value of US$1.2 billion, compared to those that favor bees (n = 15), with a value of US$19.0 billion. Limited pollinator efficiency data were available for one or more taxa in only half of the crops (n = 61; 58%). Among the non-bees, some families were recorded visiting a wide range of crops (>12), including six families of flies (Syrphidae, Calliphoridae, Muscidae, Sarcophagidae, Tachinidae, and Bombyliidae), two beetle families (Coccinelidae and Nitidulidae), ants (Formicidae), wasps (Vespidae), and four families of moths and butterflies (Hesperiidae, Lycaenidae, Nymphalidae, and Pieridae). Among the non-bees, taxa within the dipteran families Syrphidae and Calliphoridae were the most common visitors to the most crops, but this may be an artifact of the limited data available. The diversity of species and life histories in these groups of lesser-known pollinators indicates that diet, larval requirements, and other reproductive needs will require alternative habitat management practices to bees.

Pollination and resource limitation as interacting constraints on almond fruit set

Pollination and resource availability are factors determining reproductive success of plants, and in agriculture these factors influence yield of fruit-bearing crops. Our understanding of the importance of crop pollination is fast improving, but less is known about how the interaction between pollination and resources constrains fruit production. We conducted an experiment with almond trees (Prunus dulcis) to examine how the number of flowers, light availability and competition for resources affected nut (fruit) production on individual spurs (fruit-bearing structures) exposed to open-pollination or hand-pollination. We found a positive relationship between flower number and nut number on spurs with up to four flowers, but no further benefit after four flowers, suggesting a resource threshold expressed by individual spurs. Spurs with few flowers increased the conversion rate of flowers to nuts when supplemented with hand-pollination, but spurs with more flowers were more likely to achieve the threshold number of nuts even under open-pollination. Our experiment included a further treatment involving spraying whole trees with pollen. This treatment reduced nut production by spurs with many flowers and high light availability, suggesting competition is experienced by well-resourced spurs when resources need to be shared among developing nuts across the whole tree. Our study supports the hypothesis that excess flower production in fruit trees increases the potential for fruit production when pollinator and resource availability is variable (bet-hedging). Spurs with more flowers typically produce more nuts (within a limited range), but only if both resources and pollen supply increase with flower number. For almond growers, a focus on maintaining high flower numbers, especially in high light regions of the canopy, is the foundation for high levels of production. Strategies to lift flower number and light are complicated by trade-offs inherent in tree architecture and orchard design. However, fruit set would be lifted above that achieved by current practice by an increase in the pollination rate of flowers.

Prevalence and determinants of cervical cancer screening with a combination of cytology and human papillomavirus testing

PURPOSE

In the United States, recommended options for cervical cancer screening in women aged 30 years or older include cytology alone or a combination of cytology and human papillomavirus (HPV) testing (co-testing). Although there is a body of evidence suggesting that co-testing may be the preferred screening option in this group of women, little is known about the characteristics of women who screen for cervical cancer with co-testing.

METHODS

A multistage area probability design-based survey was administered to a representative sample of Texas residents. Of the 1348 female respondents, 572 women aged 30 years or older were included in this analysis. Population-weighted survey logistic regression was used to identify determinants of cervical screening with co-testing versus screening with cytology alone.

RESULTS

Women vaccinated against HPV (aOR: 4.48, 95% CI: 1.25-15.97) or hepatitis B virus [aOR: 2.48 (1.52-4.02)], those with a personal cancer history [aOR: 2.96 (1.29-6.77)], and hormonal contraception users [aOR: 2.03 (1.03-3.97)] were more likely to be screened with co-testing than with cytology alone. Moreover, the likelihood of being screened with co-testing decreased with increasing age and decreasing annual household income.

CONCLUSIONS

Benefits and indications of co-testing should be better explained to women and health care providers.

Differences in Sun Protection Behaviors Between Rural and Urban Communities in Texas

PURPOSE

The increasing incidence of skin cancer is a global health issue. In order to identify at-risk populations in Texas, we compared sun protection behaviors and sunburn history across rural and urban counties.

METHODS

An online health screening survey collected data from a nonprobability sample of Texas residents in 2018. Data were weighted by sex, age, race, and ethnicity. Multinomial multivariable logistic regression identified key factors associated with sun protection behaviors and sunscreen use. Weighted Pearson's χ²  test identified differences between urban and rural respondents in strength of sunscreen used and sunburn history.

FINDINGS

Rural residents in Texas were less likely to seek shade (OR = 0.58; P = .004) and less likely to use sunscreen lotion (OR = 0.65; P = .013) compared to their urban counterparts. Sunscreen use was also lower among current versus never smokers (OR = 0.67; P = .034) but higher in those with personal versus no cancer history (OR = 2.14; P = .004). Although rural versus urban residents were more likely to use higher SPF sunscreen (P < .002), they had more blistering sunburns over the course of their life (P < .001) and these injuries were more likely to occur at an earlier age, between 5 and 14 years old (P < .001).

CONCLUSIONS

Increased attention to sun protective behaviors among rural communities in Texas is vital to help reduce the high prevalence of sunburn injury and incidence of skin cancer.

A sea change in our view of overturning in the subpolar North Atlantic

To provide an observational basis for the Intergovernmental Panel on Climate Change projections of a slowing Atlantic meridional overturning circulation (MOC) in the 21st century, the Overturning in the Subpolar North Atlantic Program (OSNAP) observing system was launched in the summer of 2014. The first 21-month record reveals a highly variable overturning circulation responsible for the majority of the heat and freshwater transport across the OSNAP line. In a departure from the prevailing view that changes in deep water formation in the Labrador Sea dominate MOC variability, these results suggest that the conversion of warm, salty, shallow Atlantic waters into colder, fresher, deep waters that move southward in the Irminger and Iceland basins is largely responsible for overturning and its variability in the subpolar basin.

Cancer-Related Risk Perceptions and Beliefs in Texas: Findings from a 2018 Population-Level Survey

BACKGROUND

Cancer beliefs and perceptions of cancer risk affect the cancer continuum. Identifying underlying factors associated with these beliefs and perceptions in Texas can help inform and target prevention efforts.

METHODS

We developed a cancer-focused questionnaire and administered it online to a nonprobability sample of the Texas population. Weighted multivariable logistic regression analysis identified key factors associated with perceptions and beliefs about cancer.

RESULTS

The study population comprised 2,034 respondents (median age, 44.4 years) of diverse ethnicity: 45.5% were non-Hispanic white, 10.6% non-Hispanic black, and 35.7% Hispanic. Self-reported depression was significantly associated with cancer risk perceptions and cancer beliefs. Those indicating frequent and infrequent depression versus no depression were more likely to believe that: (i) compared to other people their age, they were more likely to get cancer in their lifetime [OR, 2.92; 95% confidence interval (CI), 1.95-4.39 and OR, 1.79; 95% CI, 1.17-2.74, respectively]; and (ii) when they think about cancer, they automatically think about death (OR, 2.05; 95% CI, 1.56-2.69 and OR, 1.46; 95% CI, 1.11-1.92, respectively). Frequent depression versus no depression was also associated with agreement that (i) it seems like everything causes cancer (OR, 1.67; 95% CI, 1.26-2.22) and (ii) there is not much one can do to lower one's chance of getting cancer (OR, 1.44; 95% CI, 1.09-1.89). Other predictors for perceived cancer risk and/or cancer beliefs were sex, age, ethnicity/race, being born in the United States, marital status, income, body mass index, and smoking.

CONCLUSIONS

Depression and other predictors are associated with cancer risk perceptions and beliefs in Texas.

IMPACT

Increased attention to reducing depression may improve cancer risk perceptions and beliefs.

Evaluation of a real-time PCR assay for rectal screening of OXA-48-producing Enterobacteriaceae in a general intensive care unit of an endemic hospital

Carbapenemase-producing Enterobacteriaceae are increasing worldwide. Rectal screening for these bacteria can inform the management of infected and colonized patients, especially those admitted to intensive care units (ICUs). A laboratory developed, qualitative duplex real-time polymerase chain reaction assay for rapid detection of OXA-48-like and VIM producing Enterobacteriaceae, performed on rectal swabs, was designed and evaluated in an intensive care unit with endemic presence of OXA-48. During analytical assay validation, no cross-reactivity was observed and 100% sensitivity and specificity were obtained for both bla_OXA-48-like and bla_VIM in all spiked clinical samples. During the clinical part of the study, the global sensitivity and specificity of the real-time PCR assay for OXA-48 detection were 95.7% and 100% (P=0.1250), respectively, in comparison with culture; no VIM-producing Enterobacteriaceae were detected. Clinical features of patients in the ICU who were colonized or infected with OXA-48 producing Enterobacteriaceae, including outcome, were analyzed. Most had severe underlying conditions, and had risk factors for colonization with carbapenemase-producing Enterobacteriaceae before or during ICU admission, such as receiving previous antimicrobial therapy, prior healthcare exposure (including long-term care), chronic disease, immunosuppression and/or the presence of an intravascular catheter and/or mechanical ventilation device. The described real-time PCR assay is fast (~2-3hours, if DNA extraction is included), simple to perform and results are easy to interpret, features which make it applicable in the routine of clinical microbiology laboratories. Implementation in endemic hospitals could contribute to early detection of patients colonized by OXA-48 producing Enterobacteriaceae and prevention of their spread.

The weight of US residence among immigrants: a systematic review

As the number of immigrants in the USA continues to rise, it becomes increasingly important to understand how their health differs from native-born individuals. Obesity is a public health concern and a component of health that may differ and change in important ways in immigrants. This research synthesizes the current literature on the relationship between immigrant duration of residence in the USA and body weight. Five databases from the health and social sciences were searched for all pertinent publications. Fifteen articles met inclusion criteria, 14 of which reported a significant, positive relationship between body mass index and duration of residence in the USA (all P-values <0.10). Two studies reported a threshold effect of weight gain after 10 years of US residence, and another study reported that body mass index peaks after 21 years of duration for men and after 15 years for women. The results of this review suggest that weight gain prevention programmes would be beneficial for many immigrants within the first decade of residence in the USA. Prevention efforts may be more successful if nativity and acculturation are considered in addition to race/ethnicity. Future research is needed to identify the specific mechanisms through which living in the USA may adversely affect health outcomes.

Junctional Adhesion Molecules (JAMs) are Differentially Expressed in Fibroblasts and Co-Localize with ZO-1 to Adherens-Like Junctions

Junctional Adhesion Molecules (JAMs) are components and regulators of the well-characterized epithelial and endothelial tight junction. Since the molecular components of native fibroblast adherens-like junctions remain poorly described we determined JAM expression profiles in fibroblasts. We found JAM-C on human dermal, lung, and corneal primary fibroblast cultures. Within murine lines, JAM-A was found in L-cells, JAM-C in 3T3 L1 cells, and both JAM-A and JAM-C were co-expressed in NIH 3T3 fibroblasts. In primary dermal fibroblasts, JAM-C concentrated at zipper-like junctions that formed between apposing cells. Dual immunostaining showed JAM-C co-localization with the ZO-1 intracellular scaffolding molecule at cell contacts that ranged from 7 microm to over 25 microm in length. JAM-C also labeled similar zipper-like junctions detected with N-Cadherin and Cadherin-11 antibodies. We conclude that endogenous JAM-C is an integral component of the dermal fibroblast adherens-like junction, and our data extend the expression and potential function of JAMs into mesenchymal tissues.

Herbivory differentially affects male and female reproductive traits of Cucumis sativus

Herbivory is an important selection pressure in the life history of plants. Most studies use seed or fruit production as an indication of plant fitness, but the impact of herbivory on male reproductive success is usually ignored. It is possible that plants compensate for resources lost to herbivory by shifting the allocation from seed production to pollen production and export, or vice versa. This study examined the impact of herbivory by Helix aspersa on both male and female reproductive traits of a monoecious plant, Cucumis sativus. The effects of herbivory on the relative allocation to male and female flowers were assessed through measurements of the number and size of flowers of both sexes, and the amount of pollinator visitation. We performed two glasshouse experiments; the first looked at the impact of three levels of pre-flowering herbivory, and the second looked at four levels of herbivory after the plants had started to flower. We found that herbivory during the flowering phase led to a significant increase in the number of plants without male flowers. As a consequence there was significantly less pollen export from this population, as estimated by movement of a pollen analog. The size of female flowers was reduced by severe herbivory, but there was no affect on pollen receipt by the female flowers of damaged plants. The decrease in allocation to male function after severe herbivory may be adaptive when male reproductive success is very unpredictable.

JAM2 interacts with alpha4beta1. Facilitation by JAM3

We have previously reported that junctional adhesion molecule 2 (JAM2) adheres to T cells through heterotypic interactions with JAM3. An examination of the cation dependence of JAM2 adhesion to HSB cells revealed a Mn(2+)-enhanced binding component indicative of integrin involvement. Using neutralizing integrin antibodies, we have defined an interaction between JAM2 and alpha(4)beta(1) in T cells. The interaction is readily amenable to drug intervention as demonstrated by the ability of TBC 772, an alpha(4)-specific inhibitor, to attenuate the Mn(2+)-enhanced component. Intriguingly, the engagement of alpha(4)beta(1) by JAM2 is only enabled following prior adhesion of JAM2 with JAM3 and is not detectable in cells where JAM3 expression is absent. Supporting this observation, we show that neutralizing JAM3 serum and soluble JAM3 ectodomain inhibit not only JAM2 binding to JAM3 but also prevent JAM2/alpha(4)beta(1) interactions in T cells. We further define the first Ig-like fold of JAM2 as being competent in binding both JAM3 and alpha(4)beta(1) counter-receptors. Mutagenesis of the only acidic residue in the C-D loop of this Ig fold, namely Asp-82, has no bearing on alpha(4)beta(1) interactions, and thus JAM2 deviates somewhat from the mechanism used by other immunoglobulin superfamily cell adhesion molecules to engage integrin.

Cloning of human junctional adhesion molecule 3 (JAM3) and its identification as the JAM2 counter-receptor

We have identified a third member of the junctional adhesion molecule (JAM) family. At the protein level JAM3 displays 36 and 32% identity to JAM2 and JAM1, respectively. The coding region is distributed over 9 exons and maps to chromosome 11q25. The gene shows widespread tissue expression with higher levels apparent in the kidney, brain, and placenta. At the cellular level we show expression of JAM3 transcript within endothelial cells. Our major finding is that JAM3 and JAM2 are binding partners. Thus, JAM3 ectodomain binds firmly to JAM2-Fc. This heterotypic interaction is maintained when JAM3-Fc is used to capture Chinese hamster ovary cells expressing full-length JAM2. In static adhesion assays we show that JAM3 is unable to bind to leukocyte cell lines. This is consistent with the lack of JAM2 expression. However, using JAM2-Fc pull-down experiments in combination with polyclonal anti-JAM3 serum, we demonstrate that JAM3 is the previously uncharacterized 43-kDa counter-receptor that mediates JAM2 adhesion to T cells. Most significantly we demonstrate up-regulation of JAM3 protein on peripheral blood lymphocytes following activation. Finally we show the utility of JAM3 ectodomain as an inhibitor of JAM2 adhesion.

A novel protein with homology to the junctional adhesion molecule. Characterization of leukocyte interactions

We have cloned a novel cDNA belonging to the Ig superfamily that shows 44% similarity to the junctional adhesion molecule (JAM) and maps to chromosome 21q21.2. The open reading frame of JAM2 predicts a 34-kDa type I integral membrane protein that features two Ig-like folds and three N-linked glycosylation sites in the extracellular domain. A single protein kinase C phosphorylation consensus site and a PDZ-binding motif are present in the short intracellular tail. Heterologous expression of JAM2 in Chinese hamster ovary cells defined a 48-kDa protein that localizes predominantly to the intercellular borders. Northern blot analysis showed that JAM2 is preferentially expressed in the heart. JAM2 homotypic interactions were demonstrated by the ability of JAM2-Fc to capture JAM2-expressing Chinese hamster ovary cells. We further showed that JAM2, but not JAM1, is capable of adhering to the HSB and HPB-ALL lymphocyte cell lines. Neutralizing mouse anti-JAM2 polyclonal antibodies provided evidence against homotypic interactions in this assay. Biotinylation of HSB cell membranes revealed a 43-kDa counter-receptor that precipitates specifically with JAM2-Fc. These characteristics of JAM2 led us to hypothesize a role for this novel protein in adhesion events associated with cardiac inflammatory conditions.

Motor nerve topology reflects myocyte morphology in hamster retractor and epitrochlearis muscles

Neuromuscular activation is a primary determinant of metabolic demand and oxygen transport. The m. retractor and m. epitrochlearis are model systems for studying metabolic control and oxygen transport; however, the organization of muscle fibers and motor nerves in these muscles is unknown. We tested whether the topology of motor innervation was related to the morphology of muscle fibers in m. retractor and m. epitrochlearis of male hamsters ( approximately 100 g). Respective muscles averaged 47 and 12 mm in length 100 and 35 mg in mass. Staining for acetylcholinesterase revealed neuromuscular junctions arranged in clusters throughout m. retractor and as a central band across m. epitrochlearis, suggesting differences in fiber morphology. For both muscles, complete cross-sections contained approximately 1,700 fibers. Fiber cross-sectional areas were distributed nearly normal in m. epitrochlearis (mean = 1,559 +/- 17 microm(2)) and skewed left (P < 0.05) in m. retractor (mean = 973 +/- 15 microm(2)). Single fiber length (Lf) spanned muscle length (Lm) in m. epitrochlearis, while fibers tapered to terminate within m. retractor (Lf/Lm = 0.43 +/- 0. 02). With myelin staining, a single branch of ulnar nerve projected axons across the midregion of m. epitrochlearis. For m. retractor, the spinal accessory nerve branched to give rise to proximal and distal regions of innervation, with intermingling of axons between nerve branches. Nerve bundle cross-sections stained for acetylcholinesterase indicate that each motor axon projects to an average of 65 muscle fibers in m. epitrochlearis and 100 in m. retractor. Differences in fiber morphology, innervation topology, and neuromuscular organization may contribute to the heterogeneity of metabolic demand and oxygen supply in skeletal muscle.

Depressed pollination in habitat fragments causes low fruit set

In central New South Wales, Australia, flowers of Acacia brachybotrya and Eremophila glabra plants growing in linear vegetation remnants received less pollen than conspecifics in nearby reserves. Pollen supplementation increased fruit production by both species, indicating pollen limitation of fruit set. Together these observations explain why fruit production by these species was depressed in linear-strip populations relative to nearby reserves. This study confirms that habitat fragmentation can lead to decline in pollination and subsequent fruit set in wild plant populations. Disrupted pollination interactions of the kind documented in this study may offer a substantial challenge to the conservation of biodiversity in fragmented landscapes.

Characterization of vascular endothelial cell growth factor interactions with the kinase insert domain-containing receptor tyrosine kinase. A real time kinetic study

The kinase insert domain-containing receptor (KDR) tyrosine kinase mediates calcium mobilization in endothelial cells and plays a key role during physiological and pathological angiogenesis. To provide a detailed understanding of how KDR is activated, we analyzed the kinetics of ligand-receptor interaction using BIAcore. Both predimerized (KDR-Fc) and monomeric (KDR-cbu) receptors were examined with vascular endothelial cell growth factor (VEGF) homodimers and VEGF/placental growth factor (PlGF) heterodimers. VEGF binds to KDR-Fc with ka = 3.6 +/- 0.07e6, kd = 1.34 +/- 0.19e-4, and KD = 37.1 +/- 4.9 pM. These values are similar to those displayed by monomeric KDR where ka = 5.23 +/- 1.4e6, kd = 2.74 +/- 0.76e-4, and KD = 51.7 +/- 5.8 pM were apparent. In contrast, VEGF/PlGF bound to KDR-Fc with ka = 7.3 +/- 1.6e4, kd = 4.4 +/- 1. 2e-4, and KD = 6 +/- 1.2 nM. Thus, the heterodimer displays a 160-fold reduced KD for binding to predimerized KDR, which is mainly a consequence of a 50-fold reduction in ka. We were unable to detect association between VEGF/PlGF and monomeric KDR. However, nanomolar concentrations of VEGF/PlGF were able to elicit weak calcium mobilization in endothelial cells. This latter observation may indicate partial predimerization of KDR on the cell surface or facilitation of binding due to accessory receptors.

KDR activation is crucial for VEGF165-mediated Ca2+ mobilization in human umbilical vein endothelial cells

We have prepared a polyclonal mouse antibody directed against the first three immunoglobulin-like domains of the kinase insert domain-containing receptor (KDR) tyrosine kinase. It possesses the ability to inhibit binding of the 165-amino acid splice variant of vascular endothelial cell growth factor (VEGF165) to recombinant KDR in vitro as well as to reduce VEGF165 binding to human umbilical vein endothelial cells (HUVEC). These results confirm that the first three immunoglobulin-like domains of KDR are involved in VEGF165 interactions. The anti-KDR antibody is able to completely block VEGF165-mediated intracellular Ca2+ mobilization in HUVEC. Therefore, it appears that binding of VEGF165 to the fms-like tyrosine kinase (Flt-1) in these cells does not translate into a Ca2+ response. This is further exemplified by the lack of response to placental growth factor (PlGF), an Flt-1-specific ligand. Additionally, PlGF is unable to potentiate the effects of submaximal concentrations of VEGF165. Surprisingly, the VEGF-PlGF heterodimer was also very inefficient at eliciting a Ca2+ signaling event in HUVEC. We conclude that KDR activation is crucial for mobilization of intracellular Ca2+ in HUVEC in response to VEGF165.

Interactions of FLT-1 and KDR with phospholipase C gamma: identification of the phosphotyrosine binding sites

Vascular endothelial cell growth factor interacts with the receptor tyrosine kinases Flt-1 and KDR/Flk-1. We report that both receptors bind to PLC gamma and display specificity for the N-SH2 over the C-SH2 domain. Extensive site-directed mutagenesis of Flt-1 reveals that the juxta-membrane Y794, and the carboxyl terminal Y1169, are two major sites of interaction. Amino acids in the +1, +2 and +3 positions following these tyrosines are LSI and IPI, respectively. Peptide maps generated from wild type and mutant Flt-1 confirms that these residues are autophosphorylated. As predicted, mutagenesis of the analogous amino acids in KDR, positions Y801F and Y1175F, which lie in contexts YLSI and YIVL, respectively, reduced interactions of PLC gamma with this receptor. We conclude that both Flt-1 and KDR have the potential to signal through PLC gamma via phosphotyrosine residues located in juxta-membrane and carboxyl tail regions.

Organ culture of arteries for experimental studies of vascular endothelium in situ

The objective of this study was to determine whether organ culture of arteries could be used as a more physiological model than endothelial cell culture for the study of vascular endothelium in vitro. Small pieces of artery from rat, pig, piglet and man were cultured in 24-well plates for up to seven or eight days to study the characteristics of the vascular endothelial cell layer during the first week of culture, in particular its integrity, viability and propensity for cell division. Using conventional and confocal microscopy, silver-stained endothelial cell boundaries were shown to be intact at all time points, up to and including day 7. However, occasional very small gaps between endothelial cells were seen with the scanning electron microscope under high power at day 7. Using the bromodeoxyuridine technique, no endothelial cell division was seen at day 4 in any species, except for the occasional endothelial cell in rat aorta. At day 7, pig, piglet and human arteries showed only very occasional dividing endothelial cells, but many endothelial cells had divided by day 7 in rat aorta. Viability of the endothelium was assessed using fluorochromes and examination of the endothelial layer en face using confocal microscopy. Viability was always excellent (> 95%) up to day 4. By day 7, occasional patches of dead cells could be seen, which were most obvious in rat aorta. This study demonstrates that endothelial cells can be studied in situ in organ culture with intact morphology, lack of cell division and excellent viability for a minimum of four days. For many research questions involving vascular endothelium--for example the pathophysiology of hyperacute rejection--short-term organ culture of vessels is likely to represent a more physiological model than endothelial cell culture.

Identification of the extracellular domains of Flt-1 that mediate ligand interactions

Vascular Endothelial Growth Factor (VEGF) mediates its actions through the Flt-1 and KDR(Flk-1) receptor tyrosine kinases. To localize the extracellular region of Flt-1 that is involved in ligand interactions, we prepared secreted fusion proteins between various combinations of its seven extracellular IgG-like folds. Ligand binding studies show that in combination, domains one and two (amino acids 1-234) are sufficient to achieve VEGF165 interactions. Either domain alone is insufficient to achieve this effect. However, Scatchard analysis reveals that despite the binding capabilities of this construct, the Kd is five fold lower than ligand binding to the full extracellular domain. We find that addition of domain three to this minimal site restores high affinity receptor binding. Further, we show that domains one and two are sufficient to achieve interactions of Flt-1 with Placental Growth Factor (PIGF-1).

Regulation of a sodium channel-associated G-protein by aldosterone

The action of aldosterone to increase apical membrane permeability in responsive epithelia is thought to be due to activation of sodium channels. This channel is regulated, in part, by G-proteins, but it is not known if this mechanism is regulated by aldosterone. We report that aldosterone stimulates the expression of the 41-kDa alphai3 subunit of the heterotrimeric GTP-binding proteins in A-6 cells. Both mRNA and the total amount of this protein are increased by aldosterone. The G-protein is palmitoylated in response to the steroid, and the newly synthesized subunit is found to co-localize with the sodium channel. Aldosterone stimulation of sodium transport is significantly inhibited by inhibition of palmitoylation. These results suggest that aldosterone regulates sodium channel activity in epithelia through stimulation of the expression and post-translational targeting of a channel regulatory G-protein subunit.

Cloning of an epithelial chloride channel from bovine trachea

We have isolated and cloned a novel epithelial Cl- channel protein from a bovine tracheal cDNA expression library using an antibody probe. The antibody (alpha p38) was raised against a 38-kDa component of a homopolymeric protein that behaves as a Ca2+/calmodulin kinase II-, DIDS-, and dithiothreitol (DTT)-sensitive, anion-selective channel when incorporated into planar lipid bilayers. The full-length cDNA is 3001 base pairs long and codes for a 903-amino acid protein. The clone does not show any significant homology to any other previously reported Cl- channel sequence. Northern analysis of bovine tracheal mRNA with a cDNA probe corresponding to the cloned sequence revealed a band at 3.1 kilobases, suggesting that close to the full-length sequence has been cloned. The full-length open reading frame (2712 base pairs) has been expressed in Xenopus oocytes and in mammalian COS-7 cells. In oocytes, expression of the clone was associated with the appearance of a novel DIDS-, and DTT-sensitive, anion-selective conductance that was outwardly rectified and exhibited a reversal potential close to 0 mV. Whole-cell patch clamp studies in COS-7 cells transfected with the clone identified an ionomycin-, and DTT-sensitive chloride conductance that was not apparent in mock-transfected or control cells. In vitro translation studies have shown that the primary transcript codes for a protein migrating at 140 kDa under reduced conditions, significantly larger than the polypeptide recognized by alpha p38. We therefore suggest that either the 140-kDa translated product is a prepro form of the 38-kDa subunit of the previously identified bovine tracheal anion channel and that the primary transcript is post-translationally cleaved to yield the final product, or that the cloned channel and the previously identified bovine tracheal anion channel protein share an epitope that is recognized by the alpha p38 antibody.

Interaction of the Flt-1 tyrosine kinase receptor with the p85 subunit of phosphatidylinositol 3-kinase. Mapping of a novel site involved in binding

We have examined the interactions of the p85 regulatory subunit of phosphatidylinositol 3-kinase with the endothelium-specific Flt-1 receptor tyrosine kinase using the yeast two-hybrid system. We find that both the amino- and carboxyl-terminal SH2 domains of p85 bind to Flt-1. We have performed site-directed mutagenesis on the carboxyl-terminal tail of the Flt-1 receptor in order to identify the site(s) that is responsible for the p85 interactions. A single tyrosine to phenylalanine change at position 1213 inhibits the binding of both p85 SH2 domains. Phosphopeptide mapping of the wild type and mutant protein expressed in insect cells verifies that this amino acid is a target for autophosphorylation. The amino acids following this tyrosine are VNA and thus define a novel binding site for p85.

Reading for the CSiG examination: a survey of current journals

Preparing for the new Clinical Surgery in General (CSiG) section of the Fellowship examination requires the reading of textbooks and surgical journals, the taking of mock clinicals and practice vivas. The increasing number of journals in the different branches of surgery makes it difficult for trainees to keep abreast of the current literature. A survey of surgical journals currently available in most postgraduate libraries was performed over a six-month period in order to try and identify those journals, or sections of journals, which offered most educational benefit for the CSiG candidate. We found that certain journals consistently provide excellent reviews and teaching articles and we recommend a personal reading list based on this survey.

Vesicular targeting and the control of ion secretion in epithelial cells: implications for cystic fibrosis

Non-polarized HT-29 colonic epithelial cells fail to respond to cyclic AMP-generating agonists with increases in plasma membrane anion conduction. Radio-isotopic efflux and patch-clamp experiments revealed that both undifferentiated and differentiated HT-29 colonocytes possess volume- and Ca(2+)-activated Cl- channels. However, only within the apical plasma membranes of the latter were cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channels found. CFTR was expressed equally well in both non-polarized and polarized colonocytes. Lack of CFTR-dependent anion conduction was shown to be the result of CFTR retention within a peripheral intracellular compartment. We demonstrate that upon polarization, CFTR moves to the apical plasma membrane via a Brefeldin A (BFA)-sensitive intracellular trafficking pathway.

Polarization-dependent apical membrane CFTR targeting underlies cAMP-stimulated Cl- secretion in epithelial cells

The relationship between adenosine 3',5'-cyclic monophosphate (cAMP)-mediated Cl- secretion and the cellular location of the cystic fibrosis transmembrane conductance regulator (CFTR) was determined in both polarized (Cl.19A) and unpolarized (parental) HT-29 colonocytes expressing similar levels of CFTR mRNA and protein. CFTR immunolocalized to the apical membrane domain of polarized colonocytes exhibiting cAMP-responsive Cl- secretion. In contrast, CFTR staining was perinuclear in unpolarized colonocytes, which gave little or no cAMP-stimulated Cl- conductance responses. Thus cAMP-stimulated Cl- secretion coincided with an apical localization of CFTR. Brefeldin A (BFA) was used to perturb glycoprotein targeting in these cells. In polarized colonocytes, BFA caused a reversible, time-dependent decrease in the Cl-conductance response to cAMP but not Ca2+. Apical CFTR redistributed into large coalesced intracellular vesicles, located within the same plane as the microtubule organizing center, a marker for the trans-Golgi network (TGN). In preconfluent monolayers or unpolarized HT-29 cells, BFA had no effect on CFTR staining, which remained perinuclear. Mature, Golgi-processed CFTR protein was isolated from both polarized and unpolarized colonocytes. Thus the mechanism for polarization-dependent apical membrane CFTR targeting and the acquisition of cAMP-dependent Cl- secretion lies at or beyond the late Golgi-TGN in epithelial cells.

Glycosylation status of endogenous CFTR does not affect cAMP-stimulated Cl- secretion in epithelial cells

Cystic fibrosis (CF) impairs Cl- secretion across epithelial tissues and is caused by mutations in an N-linked glycoprotein, the cystic fibrosis transmembrane conductance regulator (CFTR). We modified the glycosylation pattern of CFTR using inhibitors of oligosaccharide processing and determined their effects on both agonist-induced Cl- secretion and CFTR location in human colon (HT-29) cell lines. In both polarized and unpolarized HT-29 cells, immunoprecipitation of cell extracts using a monoclonal antibody against CFTR gave a single band at 170 kDa. Inhibitors of N-linked glycosylation reduced the molecular mass of this band: swainsonine by 10 kDa, deoxymannojirimycin by 30 kDa, and deoxynojirimycin by 10-20 kDa. However, the transepithelial Cl- current and conductance stimulated by adenosine 3',5'-cyclic monophosphate (cAMP)- or Ca(2+)-dependent secretagogues was not affected. In the polarized cells, CFTR was localized in the apical membrane domain. Treatment of the monolayers with glycoprocessing inhibitors did not affect CFTR's location. Thus, in human colonocytes that endogenously express CFTR, the extent of CFTR glycosylation does not influence the targeting of CFTR to the apical membrane domain or its function as an agonist-stimulated Cl- channel.

CFTR targeting in epithelial cells

We used polarized and nonpolarized colonic cell lines (HT-29) to correlate CFTR function and expression with epithelial cell morphogenesis. Unpolarized cells express levels of CFTR mRNA and protein that are equivalent to those observed in polarized cells, and the extent of CFTR glycosylation is also similar. Despite these similarities in CFTR expression, the polarized cells secreted Cl in response to cAMP, but there was no cAMP-stimulated Cl conductance response in the unpolarized cells. In the polarized cells, CFTR is localized in the apical membrane domain, but in unpolarized cells the protein is retained at a perinuclear location. These findings indicate that a peripheral targeting mechanism, distal to the Golgi cisternae, controls the progression of N-linked glycoproteins like CFTR to the apical membrane. This targeting process does not become active until epithelial cells polarize. It may determine whether mutant forms of CFTR are targeted to the apical membrane.

cAMP-stimulated ion currents in Xenopus oocytes expressing CFTR cRNA

The cystic fibrosis transmembrane conductance regulator (CFTR) was expressed in stage V/VI Xenopus oocytes by injection of cRNA transcribed in vitro from a pBluescript vector containing 6.2-kb wild-type cDNA. This clone was also used for the preparation of antisense RNA. Double-electrode voltage clamp was employed to measure transmembrane currents. In sense RNA-injected oocytes, cAMP depolarized the membrane potential (Vm) from -52 to -31 mV and increased membrane conductance (Gm) 10-fold. However, cAMP had no effect on Vm or Gm in uninjected oocytes or in oocytes injected with antisense RNA. The endogenous Ca-activated Cl currents of control oocytes were abolished by 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS; 50 microM) or bath Cl replacement. In contrast, the cAMP-stimulated currents of CFTR-expressing oocytes were DIDS insensitive and were inhibited only approximately 50% when bath Cl was replaced by gluconate or glutamate. In addition, the Cl channel blockers 5-nitro-2-(3-phenylpropylamino)benzoate (NPPB; 50 microM) and diphenylamine-2-carboxylic acid (DPC; 3 mM) reduced the cAMP-evoked currents by only approximately 10%. The stimulated currents of CFTR-expressing oocytes were reduced approximately 30% by 10 mM Ba, suggesting that the Cl-independent current component is due to an increase in K conductance. Our results indicate that expression of CFTR in Xenopus oocytes produces a cAMP-activated Cl current. The Cl-independent current may represent a regulatory action of CFTR on K conductance pathways or a secondary response of the oocyte membrane to the high Cl conductance induced by CFTR expression.

Cellular differentiation is required for cAMP but not Ca(2+)-dependent Cl- secretion in colonic epithelial cells expressing high levels of cystic fibrosis transmembrane conductance regulator

The gene responsible for cystic fibrosis (CF) has recently been cloned and sequenced. When transfected into CF epithelial cells, normal transcripts of this gene correct the underlying defect in CF, i.e. cAMP-dependent Cl- secretion is restored. Thus, the protein encoded by this gene, designated "cystic fibrosis transmembrane conductance regulator" (CFTR), somehow participates in the Cl- secretory response. In this paper we have correlated CFTR gene expression with cAMP and Ca(2+)-dependent Cl- secretion in unpolarized (parental) and polarized (Cl.19A) clones of the human colonic adenocarcinoma cell line HT-29. These cell lines were found to express equally high levels of CFTR mRNA at 4 days post-passage. In addition, protein expression (determined by immunoprecipitation) was also identical. The cAMP-generating agonist forskolin had little effect on 125I efflux from the unpolarized cells. In contrast, this agonist increased 125I efflux 3-fold in polarized cells. The lack of response in the unpolarized cells was not due to the inability of forskolin to raise cAMP levels. Neurotensin, a Ca(2+)-mobilizing agonist, stimulated 125I efflux from both cell lines. In the polarized cells, the magnitude of this response was attenuated at 8 days post-seeding. At this time, the undifferentiated line attained some cAMP responsiveness. This latter effect was paralleled by the appearance of monolayers within areas of the multicell layer. Cell-attached patch-clamp recording from apical membrane patches of polarized cells revealed the presence of a forskolin-stimulated 8-pS Cl- channel; no channel activity was observed in forskolin-stimulated unpolarized cells. Ca(2+)-activated Cl- channels were found in both cell lines. In agreement with the 125I efflux data, the single-channel activation response to [Ca2+]i was smaller in the polarized cell line. From these studies, we can conclude that CFTR expression, measured both at the mRNA and protein level, does not correlate with the colonocyte's ability to secrete chloride ions in response to a cAMP-generating agonist. Cyclic AMP-dependent Cl- secretion requires cellular polarization; specifically, the delineation of an apical membrane. Differences in the cellular location of CFTR during differentiation are likely to explain our results. In contrast, Ca(2+)-stimulated Cl- secretion occurred independently of cellular polarization but was reduced when the cells formed tight junctions.

Influences of separation and adjacent sequences on the use of alternative 5' splice sites

Single nucleotide changes to the sequence between two alternative 5' splice sites, separated by 25 nucleotides in a beta-globin gene derivative, caused substantial shifts in pre-mRNA splicing preferences, both in vivo and in vitro. An activating sequence for splicing was located. Models for the recognition by U1 small nuclear ribonucleoproteins (snRNPs) of competing 5' splice sites were tested by altering the distance separating the two sites. Use of the upstream splice site declined sharply when it was separated from the downstream (natural) site by distances of 40 nucleotides or more. This effect was reversed in vivo, but not in vitro, by altering the upstream sequence to that of a consensus 5' splice site sequence. Dilution of an extract used for splicing in vitro shifted preferences when the sites were close towards the downstream site. We conclude that the mechanism of selection depends on the distance apart of the potential splice sites and that with close sites steric interference between factors bound to both sites may impede splicing and affect splicing preferences.

Induction of functional uncoupling protein in guinea pigs infused with noradrenaline. Studies with isolated brown adipocytes

Continuous infusion of noradrenaline over the interscapular brown fat of guinea pigs maintained at thermoneutrality (28-32 degrees C) induces changes similar to those after cold-adaptation. (1) Multilocular fat droplets appear within the brown adipocytes. (2) The number of mitochondria per adipocyte and the total number of adipocytes both increase. (3) Noradrenaline addition to isolated adipocytes causes near maximal uncontrolled respiration. (4) The cells become more sensitive to fatty acid-induced uncoupling. (5) The tissue-specific uncoupling protein per mg of mitochondrial protein is increased 5-fold. Specific alpha- and beta-agonists were also chronically infused. (6) Separate infusion of phenylephrine or isoprenaline was not able to stimulate mitochondriogenesis or hyperplasia. (7) Adipocytes from these animals could not be uncoupled by acute noradrenaline. (8) Simultaneous chronic infusion of phenylephrine and isoprenaline reproduced the effects of chronic noradrenaline infusion.

Quantification of fatty acid activation of the uncoupling protein in brown adipocytes and mitochondria from the guinea-pig

Brown adipocytes from cold-adapted guinea-pigs (C-cells) are more sensitive to uncoupling by exogenous palmitate than are cells from warm-adapted animals (W-cells) with much less uncoupling protein. Half-maximal respiratory stimulation of C-cells requires 80 nM free palmitate. Noradrenaline-stimulated lipolysis is not rate-limiting for the respiration of either C-cells or W-cells. Half-maximal stimulation of fatty acid oxidation by mitochondria from warm-adapted guinea-pigs (W-mitochondria) and cold-adapted guinea-pigs (C-mitochondria) both require 12 nM free palmitate. Palmitate uncouples C-mitochondria much more readily than M-mitochondria, paralleling its action on the adipocytes. The uncoupling is partially saturable, about 100 nM free palmitate being required for half-maximal response of C-mitochondria. W- and C-mitochondria show identical binding characteristics for palmitate. The respiratory increase of mitochondria is calculated as a function of bound palmitate. After correcting for the residual uncoupling protein present in W-mitochondria, palmitate is estimated to be almost ineffective as an uncoupler of brown fat mitochondria in the absence of the protein. It is concluded that fatty acids display characteristics required of a necessary and sufficient physiological activator of the uncoupling protein.