Morphogens enable interacting supracellular phases that generate organ architecture

During vertebrate organogenesis, increases in morphological complexity are tightly coupled to morphogen expression. In this work, we studied how morphogens influence self-organizing processes at the collective or "supra"-cellular scale in avian skin. We made physical measurements across length scales, which revealed morphogen-enabled material property differences that were amplified at supracellular scales in comparison to cellular scales. At the supracellular scale, we found that fibroblast growth factor (FGF) promoted "solidification" of tissues, whereas bone morphogenetic protein (BMP) promoted fluidity and enhanced mechanical activity. Together, these effects created basement membrane-less compartments within mesenchymal tissue that were mechanically primed to drive avian skin tissue budding. Understanding this multiscale process requires the ability to distinguish between proximal effects of morphogens that occur at the cellular scale and their functional effects, which emerge at the supracellular scale.

Development shapes the evolutionary diversification of rodent stripe patterns

Vertebrate groups have evolved strikingly diverse color patterns. However, it remains unknown to what extent the diversification of such patterns has been shaped by the proximate, developmental mechanisms that regulate their formation. While these developmental mechanisms have long been inaccessible empirically, here we take advantage of recent insights into rodent pattern formation to investigate the role of development in shaping pattern diversification across rodents. Based on a broad survey of museum specimens, we first establish that various rodents have independently evolved diverse patterns consisting of longitudinal stripes, varying across species in number, color, and relative positioning. We then interrogate this diversity using a simple model that incorporates recent molecular and developmental insights into stripe formation in African striped mice. Our results suggest that, on the one hand, development has facilitated pattern diversification: The diversity of patterns seen across species can be generated by a single developmental process, and small changes in this process suffice to recapitulate observed evolutionary changes in pattern organization. On the other hand, development has constrained diversification: Constraints on stripe positioning limit the scope of evolvable patterns, and although pattern organization appears at first glance phylogenetically unconstrained, development turns out to impose a cryptic constraint. Altogether, this work reveals that pattern diversification in rodents can in part be explained by the underlying development and illustrates how pattern formation models can be leveraged to interpret pattern evolution.

Forced and spontaneous symmetry breaking in cell polarization

How does breaking the symmetry of an equation alter the symmetry of its solutions? Here, we systematically examine how reducing underlying symmetries from spherical to axisymmetric influences the dynamics of an archetypal model of cell polarization, a key process of biological spatial self-organization. Cell polarization is characterized by nonlinear and non-local dynamics, but we overcome the theory challenges these traits pose by introducing a broadly applicable numerical scheme allowing us to efficiently study continuum models in a wide range of geometries. Guided by numerical results, we discover a dynamical hierarchy of timescales that allows us to reduce relaxation to a purely geometric problem of area-preserving geodesic curvature flow. Through application of variational results, we analytically construct steady states on a number of biologically relevant shapes. In doing so, we reveal non-trivial solutions for symmetry breaking.

Topological braiding and virtual particles on the cell membrane

Braiding of topological structures in complex matter fields provides a robust framework for encoding and processing information, and it has been extensively studied in the context of topological quantum computation. In living systems, topological defects are crucial for the localization and organization of biochemical signaling waves, but their braiding dynamics remain unexplored. Here, we show that the spiral wave cores, which organize the Rho-GTP protein signaling dynamics and force generation on the membrane of starfish egg cells, undergo spontaneous braiding dynamics. Experimentally measured world line braiding exponents and topological entropy correlate with cellular activity and agree with predictions from a generic field theory. Our analysis further reveals the creation and annihilation of virtual quasi-particle excitations during defect scattering events, suggesting phenomenological parallels between quantum and living matter.

Marginal warming associated with a COVID-19 quarantine and the implications for disease transmission

During January-February 2020, parts of China faced restricted mobility under COVID-19 quarantines, which have been associated with improved air quality. Because particulate pollutants scatter, diffuse, and absorb incoming solar radiation, a net negative radiative forcing, decreased air pollution can yield surface warming. As such, this study (1) documents the evolution of China's January-February 2020 air temperature and concurrent particulate changes; (2) determines the temperature response related to reduced particulates during the COVID-19 quarantine (C19Q); and (3) discusses the conceptual implications for temperature-dependent disease transmission. C19Q particulate evolution is monitored using satellite analyses, and concurrent temperature anomalies are diagnosed using surface stations and Aqua AIRS imagery. Meanwhile, two WRF-Chem simulations are forced by normal emissions and the satellite-based urban aerosol changes, respectively. Urban aerosols decreased from 27.1% of pre-C19Q aerosols to only 17.5% during C19Q. WRF-Chem resolved ~0.2 °C warming across east-central China, that represented a minor, though statistically significant contribution to C19Q temperature anomalies. The largest area of warming is concentrated south of Chengdu and Wuhan where temperatures increased between +0.2-0.3 °C. The results of this study are important for understanding the anthropogenic forcing on regional meteorology. Epidemiologically, the marginal, yet persistent, warming during C19Q may retard temperature-dependent disease transmission, possibly including SARS-CoV-2.

Gait-optimized locomotion of wave-driven soft sheets

Inspired by the robust locomotion of limbless animals in a range of environments, the development of soft robots capable of moving by localized swelling, bending, and other forms of differential growth has become a target for soft matter research over the last decade. Engineered soft robots exhibit a wide range of morphologies, but theoretical investigations of soft robot locomotion have largely been limited to slender bodied or one-dimensional examples. Here, we demonstrate design principles regarding the locomotion of two-dimensional soft materials driven by morphoelastic waves along a dry substrate. Focusing on the essential common aspects of many natural and man-made soft actuators, a continuum model is developed which links the deformation of a thin elastic sheet to surface-bound excitation waves. Through a combination of analytic and numerical methods, we investigate the relationship between induced active stress and self-propulsion performance of self-propelling sheets driven by FitzHugh-Nagumo type chemical waves. Examining the role of both sheet geometry and terrain geography on locomotion, our results can provide guidance for the design of more efficient soft crawling devices.

Structural Redundancy in Supracellular Actomyosin Networks Enables Robust Tissue Folding

Tissue morphogenesis is strikingly robust. Yet, how tissues are sculpted under challenging conditions is unknown. Here, we combined network analysis, experimental perturbations, and computational modeling to determine how network connectivity between hundreds of contractile cells on the ventral side of the Drosophila embryo ensures robust tissue folding. We identified two network properties that mechanically promote robustness. First, redundant supracellular cytoskeletal network paths ensure global connectivity, even with network degradation. By forming many more connections than are required, morphogenesis is not disrupted by local network damage, analogous to the way redundancy guarantees the large-scale function of vasculature and transportation networks. Second, directional stiffening of edges oriented orthogonal to the folding axis promotes furrow formation at lower contractility levels. Structural redundancy and directional network stiffening ensure robust tissue folding with proper orientation.

Geometry of Wave Propagation on Active Deformable Surfaces

Fundamental biological and biomimetic processes, from tissue morphogenesis to soft robotics, rely on the propagation of chemical and mechanical surface waves to signal and coordinate active force generation. The complex interplay between surface geometry and contraction wave dynamics remains poorly understood, but it will be essential for the future design of chemically driven soft robots and active materials. Here, we couple prototypical chemical wave and reaction-diffusion models to non-Euclidean shell mechanics to identify and characterize generic features of chemomechanical wave propagation on active deformable surfaces. Our theoretical framework is validated against recent data from contractile wave measurements on ascidian and starfish oocytes, producing good quantitative agreement in both cases. The theory is then applied to illustrate how geometry and preexisting discrete symmetries can be utilized to focus active elastic surface waves. We highlight the practical potential of chemomechanical coupling by demonstrating spontaneous wave-induced locomotion of elastic shells of various geometries. Altogether, our results show how geometry, elasticity, and chemical signaling can be harnessed to construct dynamically adaptable, autonomously moving mechanical surface waveguides.

Actomyosin-based tissue folding requires a multicellular myosin gradient

Tissue folding promotes three-dimensional (3D) form during development. In many cases, folding is associated with myosin accumulation at the apical surface of epithelial cells, as seen in the vertebrate neural tube and the Drosophila ventral furrow. This type of folding is characterized by constriction of apical cell surfaces, and the resulting cell shape change is thought to cause tissue folding. Here, we use quantitative microscopy to measure the pattern of transcription, signaling, myosin activation and cell shape in the Drosophila mesoderm. We found that cells within the ventral domain accumulate different amounts of active apical non-muscle myosin 2 depending on the distance from the ventral midline. This gradient in active myosin depends on a newly quantified gradient in upstream signaling proteins. A 3D continuum model of the embryo with induced contractility demonstrates that contractility gradients, but not contractility per se, promote changes to surface curvature and folding. As predicted by the model, experimental broadening of the myosin domain in vivo disrupts tissue curvature where myosin is uniform. Our data argue that apical contractility gradients are important for tissue folding.

Impact fragmentation of model flocks

Predicting the bulk material properties of active matter is challenging since these materials are far from equilibrium and standard statistical-mechanics approaches may fail. We report a computational study of the surface properties of a well known active matter system: aggregations of self-propelled particles that are coupled via an orientational interaction and that resemble bird flocks. By simulating the impact of these models flocks on an impermeable surface, we find that they fragment into subflocks with power-law mass distributions, similar to shattering brittle solids but not to splashing liquid drops. Thus, we find that despite the interparticle interactions, these model flocks do not possess an emergent surface tension.

A model of destination-language acquisition: application to male immigrants in Canada

We develop a model using human capital theory and an immigrant adjustment process to generate hypotheses on the acquisition of destination-language skills among immigrants. The model is tested for adult male immigrants in the 1991 Census of Canada. Use of English or French is greater, the younger the age at migration, the longer the duration of residence, the higher the educational attainment, the farther the country of origin from Canada, and the linguistically closer the mother tongue to English or French, and among those who are not refugees, those from a former British, French, or American colony, and those who live in an area where fewer people speak the respondent's mother tongue. The explanatory variables based on birthplace have behavioral interpretations and possess almost as much explanatory power as the birthplace dummy variables.

Sensitivity of the denaturing gradient gel electrophoresis technique in detection of known mutations and novel Asian mutations in the CFTR gene

More than 500 mutations have been identified in the CFTR gene, making it an excellent system for testing mutation scanning techniques. To assess the sensitivity of denaturing gradient gel electrophoresis (DGGE), we collected a representative group of 202 CFTR mutations. All mutations analyzed were detected by scanning methods other than the DGGE approach evaluated in this study. DGGE analysis was performed on 24 of the 27 exons and their flanking splice site sequences. After optimization, 201 of the 202 control samples produced an altered migration pattern in the region in which an alteration occurred. The remaining sample was sequenced and found not to have the reported mutation. The ability of DGGE to identify novel mutations was evaluated in three Asian CF patients with four unknown CF alleles. Three novel Asian mutations were detected-K166E, L568X, and 3121-2 A-->G (in homozygosity)-accounting for all CF alleles. These results indicate that an optimized DGGE scanning strategy is highly sensitive and specific and can detect 100% of mutations.

Intratumoral administration of adenoviral interleukin 7 gene-modified dendritic cells augments specific antitumor immunity and achieves tumor eradication

In two murine lung cancer models adenoviral interleukin 7-transduced dendritic cells (DC-AdIL-7) were administered intratumorally, resulting in complete tumor regression. Intratumoral DC-AdIL-7 therapy was as effective as DCs pulsed with specific tumor peptide antigens. Comparison with other intratumoral therapies including recombinant IL-7, AdIL-7 vector alone, unmodified DCs, IL-7-transduced fibroblasts, or DCs pulsed with tumor lysates revealed DC-AdIL-7 therapy to be superior in achieving antitumor responses and augmenting immunogenicity. Mice with complete tumor eradication as a result of either DC-AdIL-7 or AdIL-7 therapy were rechallenged with parental tumor cells 30 days or more after complete tumor eradication. All the DC-AdIL-7-treated mice completely rejected a secondary rechallenge, whereas the AdIL-7-treated mice had sustained antitumor effects in only 20-25% of the mice. DC-AdIL-7 therapy was more effective than AdIL-7 in achieving systemic antitumor responses and enhancing immunogenicity. After complete tumor eradication, those mice treated with DC-AdIL-7 evidenced significantly greater release of splenocyte GM-CSF and IFN-gamma than did controls or AdIL-7-treated mice. After intratumoral injection, gene-modified DCs trafficked from the tumor to lymph node sites and spleen. DCs were detected in nodal tissues for up to 7 days after intratumoral injection. We report that intratumoral DC-AdIL-7 leads to significant systemic immune responses and potent antitumor effects in murine lung cancer models.

Specific inhibition of cyclooxygenase 2 restores antitumor reactivity by altering the balance of IL-10 and IL-12 synthesis

Cyclooxygenase-2 (COX-2), the enzyme at the rate-limiting step of prostanoid production, has been found to be overexpressed in human lung cancer. To evaluate lung tumor COX-2 modulation of antitumor immunity, we studied the antitumor effect of specific genetic or pharmacological inhibition of COX-2 in a murine Lewis lung carcinoma (3LL) model. Inhibition of COX-2 led to marked lymphocytic infiltration of the tumor and reduced tumor growth. Treatment of mice with anti-PGE2 mAb replicated the growth reduction seen in tumor-bearing mice treated with COX-2 inhibitors. COX-2 inhibition was accompanied by a significant decrement in IL-10 and a concomitant restoration of IL-12 production by APCs. Because the COX-2 metabolite PGE2 is a potent inducer of IL-10, it was hypothesized that COX-2 inhibition led to antitumor responses by down-regulating production of this potent immunosuppressive cytokine. In support of this concept, transfer of IL-10 transgenic T lymphocytes that overexpress IL-10 under control of the IL-2 promoter reversed the COX-2 inhibitor-induced antitumor response. We conclude that abrogation of COX-2 expression promotes antitumor reactivity by restoring the balance of IL-10 and IL-12 in vivo.

T cell-derived IL-10 promotes lung cancer growth by suppressing both T cell and APC function

We have found previously that human lung cancers potently induce T lymphocyte IL-10 production in vitro. To assess the impact of enhanced T cell-derived IL-10 on antitumor immunity in vivo, we utilized transgenic mice expressing IL-10 under the control of the IL-2 promoter. We have shown previously that Lewis lung carcinoma cells (3LL) have more aggressive growth potential in IL-10 transgenic mice compared with control littermates. In this study, we show that transfer of T cells from IL-10 transgenic mice to control littermates transferred the IL-10 immunosuppressive effect and led to enhanced 3LL tumor growth. In addition to changes in T cell-mediated immunity, professional APC from IL-10 transgenic mice were found to have significantly suppressed capacity to induce MHC alloreactivity, CTL responses, and IL-12 production. Tumor Ag-pulsed dendritic cells from IL-10 transgenic mice also failed to generate antitumor reactivity. These results suggest that increased levels of T cell-derived IL-10 severely impair antitumor immunity in vivo, due to defects in both T cell and APC function.

Language skills and earnings among legalized aliens

"This paper uses the data on males and females from the 1989 [U.S.] Legalized Population Survey (LPS), a sample of aliens granted amnesty under 1986 Immigration Reform and Control Act, to analyse English language proficiency and earnings.... English language proficiency is greater for those with more schooling, who immigrated at a younger age, who have been in the United States longer, with a more continuos stay, and who have less access to other origin language speakers where they live. Earnings are higher by about 8% for men and 17% for women who are proficient in both speaking and reading English, compared to those lacking both skills."

Dendritic cells augment granulocyte-macrophage colony-stimulating factor (GM-CSF)/herpes simplex virus thymidine kinase-mediated gene therapy of lung cancer

Lung cancer, the leading cause of cancer death in the United States, is resistant to most currently available therapies. To evaluate a multicomponent gene therapy approach that replaces tumor-bearing host immune deficits, we genetically modified Line 1 (L1C2), a weakly immunogenic alveolar cell carcinoma cell line. L1C2 was transduced ex vivo with a retroviral construct that contained two components: a cytokine gene (granulocyte-macrophage colony-stimulating factor) and a drug sensitivity gene (herpes simplex virus thymidine kinase). The third component of this therapy, in vitro-activated syngeneic bone marrow-derived dendritic cells, was included to augment antigen presentation. The addition of ganciclovir (GCV) caused the lysis of transduced tumor cells, resulting in the release of potential tumor antigens. Ex vivo-transduced tumor cells regressed in vivo following GCV therapy but were not effective in the treatment of established parental tumors. To treat established tumors, dendritic cells were administered in combination with transduced tumor cells and GCV. A total of 50% of these mice rejected the 5-day-old established tumors and were immune to rechallenge with parental L1C2 cells. Thus, this multicomponent gene therapy system leads to both the regression of established tumors and enhanced immunogenicity in this weakly immunogenic murine lung cancer model.

Gene therapy for lung cancer

Gene therapy has received considerable attention and some speculation as to its value. Although few patients have been treated, the preliminary results of the phase I lung cancer gene therapy clinical trials are very promising. Clinically relevant basic research in the molecular pathogenesis and immunology of lung cancer is progressing. As improved vector technologies are developed, new opportunities will be available to initiate lung cancer gene therapy trials that are based on a more detailed understanding of lung cancer biology. In conclusion, although important biologic and technical questions remain unanswered, recent research suggests that gene therapy will have a profound impact on lung cancer treatment.

Alternative splicing of a precursor-mRNA encoded by the Chlorella sorokiniana NADP-specific glutamate dehydrogenase gene yields mRNAs for precursor proteins of isozyme subunits with different ammonium affinities

Chlorella sorokiniana has seven ammonium-inducible, chloroplastic NADP-specific glutamate dehydrogenase (NADP-GDH) isozymes composed of varying ratios of alpha- and beta-subunits. Southern blot and allele-specific PCR analyses indicate that the C. sorokiniana genome possesses a single 7178 bp nuclear NADP-GDH gene. cDNA cloning and sequencing, 5'-RACE-PCR analysis, and RNase protection analysis identified two NADP-GDH mRNAs that are identical with the exception of a 42 nt sequence located within the 5'-coding region of the longer mRNA. The 42 nt sequence, termed an auxon because it serves as an exon or intron, appears to undergo alternative splicing from the precursor mRNA by a process that is regulated by both nutritional and environmental signals. Depending upon whether the auxon is included or excluded in a mature mRNA, the gene can be considered to consist of 22 or 23 exons, respectively. The 2074 and 2116 nt mRNAs encode precursor proteins of 56,350 and 57,850 Da, respectively. The N-termini of the purified mature alpha- and beta-subunits were sequenced, identifying full-length subunits of 53,501 and 52,342 Da, respectively. The sequences of the subunits are identical except for an 11 amino acid extension at the N-terminus of the alpha-subunit. The alpha-subunit has an additional alpha-helical domain at its N-terminus compared with the beta-subunit. By correlating the abundances of the two mRNAs with the levels (and relative turnover rates) of the alpha- and beta-subunit antigens during induction in Chlorella, the larger mRNA is proposed to encode the larger subunit.

Non-small cell lung cancer cyclooxygenase-2-dependent regulation of cytokine balance in lymphocytes and macrophages: up-regulation of interleukin 10 and down-regulation of interleukin 12 production

Tumor-derived prostaglandin E2 (PGE2) modifies cytokine balance and inhibits host immunity. We hypothesized that a high level of PGE2 production by lung tumor cells is dependent on tumor cyclooxygenase (COX)-2 expression. We found that PGE2 production by A549 non-small cell lung cancer (NSCLC) cells was elevated up to 50-fold in response to interleukin (IL)-1beta. Reversal of IL-1beta-induced PGE2 production in A549 cells was achieved by specific pharmacological or antisense oligonucleotide inhibition of COX-2 activity or expression. In contrast, specific COX-1 inhibition was not effective. Consistent with these findings, IL-1beta induced COX-2 mRNA expression and protein production in A549 cells. Specific inhibition of COX-2 abrogated the capacity of IL-1beta-stimulated A549 cells to induce IL-10 in lymphocytes and macrophages. Furthermore, specific inhibition of A549 COX-2 reversed the tumor-derived PGE2-dependent inhibition of macrophage IL-12 production when whole blood was cultured in tumor supernatants. Our results indicate that lung tumor-derived PGE2 plays a pivotal role in promoting lymphocyte and macrophage IL-10 induction while simultaneously inhibiting macrophage IL-12 production. Immunohistochemistry of human NSCLC tissues obtained from lung cancer resection specimens revealed cytoplasmic staining for COX-2 within tumor cells. This is the first description of functional COX-2 expression by NSCLC cells and the definition of a pathway whereby tumor COX-2 expression and a high level of PGE2 production mediate profound alteration in cytokine balance in the lung cancer microenvironment.

Multicomponent gene therapy vaccines for lung cancer: effective eradication of established murine tumors in vivo with interleukin-7/herpes simplex thymidine kinase-transduced autologous tumor and ex vivo activated dendritic cells

Multiple antitumor modalities may be necessary to overcome lung tumor-mediated immunosuppression and effectively treat non-small cell lung cancer (NSCLC). To evaluate a multimodality gene therapy approach for control of local tumor growth, a weakly immunogenic murine alveolar cell carcinoma, L1C2, was transduced with either the interleukin-7/hygromycin-herpes simplex thymidine kinase (IL-7/HyHSVtk) internal ribosome entry site (IRES) retroviral vector or a vector containing the HyHSVtk, but not the IL-7 gene. Of the many cytokines available for gene transfer, IL-7 was chosen for these studies because it both stimulates CTL responses and down-regulates tumor production of the immunosuppressive peptide TGF-beta. Following selection in hygromycin, IL-7 transduction was confirmed by ELISA. Clones produced 1.25 to 10 ng of IL-7/ml/10(6) cells per 24 h. In vitro, genetically modified tumor cells were significantly more sensitive to ganciclovir (GCV) than unmodified parental tumor cells. The in vivo growth of ex vivo modified L1C2 cells was evaluated. There was a dose-response relationship between the amount of IL-7 secreted in vitro and the growth of genetically modified murine tumor in vivo. Transduced tumor cells regressed in mice following GCV therapy. Although ex vivo gene modification of tumor cells led to complete resolution of the tumor following implantation in vivo, IL-7 and HSVtk gene modified tumor cells were not effective in treating established parental tumors. However when 5 x 10(5) bone marrow-derived, in vitro activated dendritic cells (DC) were administered in combination with transduced tumor and GCV, 5 day old established tumors were eradicated in 80% of mice. These studies suggest that multicomponent vaccines may facilitate improved host responses by replacing host immune deficits and thus could have a role in adjuvant therapy and local control of NSCLC.

Molecular organization and tissue-specific expression of an Arabidopsis 14-3-3 gene

The 14-3-3 proteins, originally described as mammalian brain proteins, are ubiquitous in eukaryotes. We isolated an Arabidopsis 14-3-3 gene, designated GRF1-GF14 chi (for general regulatory factor1-G-box factor 14-3-3 homolog isoform chi), and characterized its expression within plant tissues. Sequence comparison of the GRF1-GF14 chi genomic clone with other 14-3-3 proteins demonstrated that the extreme conservation of 14-3-3 residues in several domains is encoded by the first three exons. The highly variable C-terminal domain is encoded by a divergent fourth exon that is unique among 14-3-3 homologs, suggesting that exon shuffling might confer gene-specific functions among the isoforms. The anatomical distribution and developmental expression of the Arabidopsis 14-3-3 protein were examined in transgenic plants carrying a GRF1-GF14 chi promoter-beta-glucuronidase construct. GF14 chi promoter activity was observed in the roots of both seedlings and mature plants. In immature flowers, GF14 chi promoter activity was localized to the buds. However, as the flowers matured, GF14 chi promoter activity was restricted to the stigma, anthers, and pollen. In immature siliques, GF14 chi promoter activity was initially localized to styles and abscission zones but was subsequently observed throughout mature siliques. In situ hybridization demonstrated that GF14 chi mRNA expression was prominent in epidermal tissue of roots, petals, and sepals of flower buds, papillae cells of flowers, siliques, and endosperm of immature seeds. Thus, plant 14-3-3 gene expression exhibits cell- and tissue-specific localization rivaling that observed for 14-3-3 proteins within the mammalian brain.

Cystic fibrosis transmembrane conductance regulator (CFTR) gene mutations in allergic bronchopulmonary aspergillosis

The etiology of allergic bronchopulmonary aspergillosis (ABPA) is not well understood. A clinical phenotype resembling the pulmonary disease seen in cystic fibrosis (CF) patients can occur in some individuals with ABPA. Reports of familial occurrence of ABPA and increased incidence in CF patients suggest a possible genetic basis for the disease. To test this possibility, the entire coding region of the cystic fibrosis transmembrane regulator (CFTR) gene was analyzed in 11 individuals who met strict criteria for the diagnosis of ABPA and had normal sweat electrolytes (< or = 40 mmol/liter). One patient carried two CF mutations (deltaF508/R347H), and five were found to carry one CF mutation (four deltaF508; one R117H). The frequency of the deltaF508 mutation in patients with ABPA was significantly higher than in 53 Caucasian patients with chronic bronchitis (P < .0003) and the general population (P < .003). These results suggest that CFTR plays an etiologic role in a subset of ABPA patients.

Ethnic networks and language proficiency among immigrants

"This paper uses a unique data set for Australia (1988) that includes a variety of ethnic network variables to analyze the role of the language concentration measure [in immigrants' acquisition of the language of the destination country]. These ethnic variables, in particular, ethnic press, relatives in Australia, and spouse's origin language, are highly statistically significant. Their inclusion in the equation eliminates the effect of the minority-language concentration variable. The model for analyzing the determinants of English reading and English writing skills in Australia is also shown to be very similar to the model for speaking fluency, including the effect of the ethnic network variables."

Language choice among immigrants in a multi-lingual destination

"This paper analyzes the choice of dominant destination language spoken by immigrants in a multi-lingual destination. The empirical analysis is performed for Canada."

The earnings of Asian male immigrants in the Canadian labor market

"The earnings of Asian-born immigrants in the Canadian labor market declined relative to the earnings of native-born workers between 1981 and 1986. Analysis of the labor market performance of immigrants from four regions of Asia--Southern Asia, South East Asia, Eastern Asia and Western Asia--shows that Asian immigrants are a heterogeneous group. However, changes in the birthplace composition of Asian immigrants cannot explain the fall in the relative earnings of the Asian aggregate. Attention is drawn to the switch in the distribution of immigrants across the admission classes as a possible explanation of this phenomenon."

Economic models of fertility behaviour in Australia

The author analyses individual fertility patterns in Australia from the perspective of recent economic models of the family. The emphasis is on the relationship between fertility and economic variables such as human capital, market wages, and wealth. "Several dimensions of fertility are considered, including 'quality' of children, completed family size, and the decision whether to have children or not." Data are from the 1973 Social Mobility in Australia Survey.

Urgent thoracotomy for pulmonary or tracheobronchial injury

Three hundred eighty-eight of 7,283 (5.3%) admitted trauma patients underwent urgent thoracotomy. In 61 patients (15.7%), pulmonary or tracheobronchial injury prompted thoracotomy (11, blunt; 50, penetrating). Pulmonary hemorrhage necessitated thoracotomy in 54 patients (88.5%); tracheobronchial injury in five patients (8.2%). The mortality was 27.9%. Nine patients (14.8%) underwent pneumonectomy: eight died of intractable hemorrhagic shock during thoracotomy despite rapid control of pulmonary hemorrhage: one died of sepsis. Eleven patients (18.0%) underwent lobectomy: six (54.5%) died of concomitant injuries. Thirty-six patients (59.0%) underwent pneumonorrhaphy: one died of concomitant injuries. Five (8.2%) patients underwent tracheobronchial repair: one died of concomitant injuries. Pneumonectomy was uniformly fatal and should be a procedure of last resort in the treatment of pulmonary injury, as lobectomy and pneumonorraphy are better tolerated by these critically ill patients.

Earnings in Canada: the roles of immigrant generation, French ethnicity, and language

"The effects of immigrant status, French ethnicity, and language fluency in Canada has received relatively little attention in the economics literature. Moreover, the coverage of the few studies available is highly selective, and the results often conflict. This paper seeks to correct these deficiencies by using data from the 1971 and 1981 Censuses of Canada to analyze the labor market adjustment of immigrants and French Canadians, as well as the role of language in the Canadian labor market. The analysis is conducted in a manner which will facilitate comparison with previous studies of immigrants and their children in Canada and in other countries. In addition, by comparing 1971 and 1981 Census data, the paper highlights the similarity and changes in patterns over the decade."

Ranitidine in the newborn

An infusion of ranitidine 0.2 mg/kg/hour abruptly halted a life threatening gastrointestinal haemorrhage in an anuric infant of 30 weeks' gestation.

Aspects of occupational mobility and attainment among immigrants in Australia

The occupational distributions of the native-born and foreign-born in the Australian labor market differ greatly. The disparity between the occupational distributions is greatest among the middle age-bracket, and among immigrants from Eastern Europe and the Mediterranean region. Analysis of occupational attainment using unit record data from the 1981 Census shows that as duration of residence in Australia lengthens, the occupational distribution of the overseas-born converges toward that of the Australian-born. Moreover, birthplace groups differ in the degree of upward mobility associated with length of residence in Australia: immigrants from non-English-speaking countries tend to make greater occupational advances than their counterpart from English-speaking countries. This suggests a higher degree of international transferability of human capital skills among immigrants from English-speaking countries. The analysis also highlights the concentration of immigrants from non-English speaking countries in low-ranked occupations, and the relatively minor influence of education on the occupational attainment of immigrants from these birth place regions.

Dating the time interval from meconium passage to birth

The gross and microscopic effects of exposing placenta and umbilical cord to meconium were studied in vitro. Gross staining begins with one hour and is a surface phenomenon proportional to length of exposure and meconium concentration. Pigment penetration into the membranes with subsequent uptake by macrophages is dependent primarily on exposure length. Eight of 11 placentas exposed to various meconium solutions were found to have meconium pigment-laden macrophages in the amnion after one hour. These were seen in the chorion somewhat later. Although only three of 11 placentas showed chorionic pigmented macrophages at one hour, 12 of 12 exhibited this finding after three hours. Amniotic epithelial degeneration also showed a time correlation. These findings, especially the microscopic changes described, permit more accurate determination of the defecation-to-birth interval.

The significance of scapular fractures

Scapular fractures in the multiply injured patient have received little attention. Fifty-six patients with 58 scapular fractures secondary to blunt trauma were reviewed. The patients averaged 3.9 major injuries excluding their scapular fractures. The injury pattern associated with blunt scapular fracture is unique. Patients with scapular fracture have a high incidence of injury to the ipsilateral lung and chest wall and to the ipsilateral shoulder girdle and its contained structures: rib fractures, 53.6%; pulmonary contusions, 53.6%; clavicular fracture, 26.8%; brachial plexus injury, 12.5%; subclavian, brachial, or axillary artery injury, 10.7%. Eight patients died (14.3%). Although no patient died from the scapular fracture, half of the deaths in this series were the result of pulmonary sepsis arising in an associated ipsilateral pulmonary contusion. Scapular fractures provide the trauma surgeon with a reliable clinical clue that the patient is at inordinate risk to have associated injuries of major consequence to the ipsilateral lung and chest wall, the ipsilateral shoulder girdle, and the ipsilateral subclavian, axillary, or brachial artery.

The economics of fatal injury: dollars and sense

This study reviewed the direct costs (charges for goods and services) for 77 consecutive patients who presented to this trauma service with a Trauma Score (TS) of four or less. Seventy-four patients died (96.1%). The survival rates based upon the Trauma Scores were: TS 1, 0(0/34); TS 2, 0(0/9); TS 3, 7.7% (1/13); TS 4, 9.5% (2/21). Only four nonsurvivors lived more than 24 hours. The remaining 70 patients died within 24 hours without achieving even transient cardiovascular stability. Three of the 77 patients survived (3.9%) but only one achieved a productive recovery. The total direct cost for the 77 patients was +544,477.66. Physician fees, which accounted for 26.7% of the direct costs, averaged +1,887.57 per patient (range, 0-+11,291.00). The average direct cost for the three survivors was +50,138.94. The average direct cost for nonsurvivors was +5,325.18 (+3,383.29 for patients with a TS 1 or 2, +8,018.76 for patients with a TS 3 or 4). The hospital direct costs for nonsurvivors ranged from +40.00 for a patient declared dead on arrival to +57,817.91 for a patient who died 41 days after admission. It is futile to continue resuscitational efforts if a valid Trauma Score of 1 or 2 is confirmed shortly after the initiation of appropriate resuscitative measures. Continued therapy is futile for the remainder of patients admitted with Trauma Scores of 4 or less if they do not achieve cardiovascular stability in response to appropriate resuscitative measures within 1 hour of admission.(ABSTRACT TRUNCATED AT 250 WORDS)

Urban helicopter response to the scene of injury

Metropolitan Houston with a population of four million has the nation's poorest freeway system. Its two Level I trauma centers are adjacent within a centrally located freeway loop, therefore the city is ideally suited for a trauma scene helicopter transport service. During 1981 there were 577 flights to the scene of injury (blunt, 466; penetrating, 111). Flights were requested by 60 agencies (EMS, law enforcement, etc.). All flights were manned by a surgical resident and flight nurse. The flight distances ranged from 2 to 57 miles (average, 14.4). Three hundred six flights (53%) were within the city, including 59 (10.2%) within the freeway loop. In approximately one half of the flights, the initial responding EMS unit was a paramedic unit. The average time at the scene was 28 minutes. The overall mortality for trauma scene flights was 35.7% (206/577). Eighty-nine patients (15.1%) died at the scene and were not transported (initial median scene Trauma Score, 2). The mortality among transported patients was 24.0% (117/488). Twenty-nine patients died during attempted emergency-center resuscitation (initial median scene Trauma Score, 5). Eight-eight patients died after hospital admission (initial median scene Trauma Score, 10). Only 27 patients (5.5%) did not require hospitalization. Scene treatment (intubation, hyperventilation and, when appropriate, mannitol administration) was routinely initiated for patients with severe head injuries. Two hundred seventy-nine patients required cardiopulmonary resuscitation, tracheal intubation, chest-tube placement, or other invasive procedures. Based upon these resuscitative efforts and invasive procedures, a physician in attendance was deemed medically desirable for one half of the flights.(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnostic peritoneal lavage in blunt trauma patients with coagulopathy

Coagulopathies such as dilutional coagulopathy secondary to massive crystalloid and/or blood resuscitation, and disseminated intravascular coagulation secondary to head injury, complicate the care of severely traumatized patients. The accuracy of diagnostic peritoneal lavage has not been appraised in patients with coagulopathy. During a 3-year period, 847 patients underwent diagnostic peritoneal lavage using the direct visualization, open method. Exploratory laparotomy was performed on 298 patients for a positive diagnostic peritoneal lavage. All patients had coagulation studies prior to diagnostic peritoneal lavage. Twenty-eight patients (9.4%) with a mean injury severity score of 45, had coagulopathy prior to diagnostic peritoneal lavage. Only 2% (6/298) of the diagnostic peritoneal lavages were falsely positive despite the presence of pelvic fractures in 24.5% (73/298) of the patients. The incidence of falsely positive diagnostic peritoneal lavage was similar (P = .5) for patients with coagulopathy (3.6%, 1/28) as compared to patients without coagulopathy (1.8%, 5/272). Following blunt trauma, clinical indications for diagnostic peritoneal lavage do not mandate coagulation screening because diagnostic peritoneal lavage is reliable in patients with preexisting coagulopathy.

Peritoneal lavage and angiography in the management of patients with pelvic fractures

One hundred consecutive patients with pelvic fractures who had undergone peritoneal lavage and abdominal and pelvic angiography were retrospectively analyzed. Sixty-four patients with negative lavages were treated successfully without laparotomy despite a 20 percent incidence of subcapsular or intraparenchymal hematomas of the liver or spleen. Thirty percent of the patients with positive peritoneal lavages were successfully managed without laparotomy when abdominal angiography failed to identify a source of active bleeding. Abdominal angiography was 92 percent accurate in predicting the presence or absence of hemorrhage in 25 patients who underwent laparotomy. There were no false-positive angiograms. The overall false-negative rate was 2.12 percent. These occurred in two patients with torn mesenteric vessels. Pelvic angiography identified arterial pelvic bleeding in 18 percent of the patients. Eighty-four percent of patients with major pelvic bleeding had successful embolization with prompt cessation of arterial bleeding. We conclude that abdominal and pelvic angiography can be a useful adjunct to peritoneal lavage in detecting intraperitoneal hemorrhage and can be of therapeutic value for arterial pelvic bleeding.

Emergency department thoracotomy

The charts of 33 consecutive patients undergoing emergency department thoracotomies between July 1, 1979 and June 30, 1980 were reviewed. Thoracotomies were performed in victims of both blunt and penetrating trauma who had suffered cardiopulmonary arrest and were refractory to the usual methods of resuscitation. Overall survival was 12.1% (4/33). There were no survivors from blunt trauma or penetrating wounds below the diaphragm. In patients with penetrating wounds above the diaphragm, emergency thoracotomy may be considerable benefit as demonstrated in our study by a 66.6% salvage rate.

Factors affecting mortality in pelvic fractures

Review of 100 consecutive patients with pelvic fractures admitted to a trauma service during an 11-month period was undertaken in order to define the factors which affected the mortality. Mortality was most significantly affected by severity of injury, presence of a head injury, admitting blood pressure, admitting hemoglobin level, and requirements for blood and blood products. Evaluation of anatomic configuration of fractures demonstrated that posterior fractures required larger amounts of blood and blood products, had a significantly decreased admitting blood pressure, and had a significantly higher mortality, despite there being no significant difference in injury severity between patients having anterior or posterior fractures.

Effects of ethanol ingestion on the severity and outcome of trauma

Review of 1,198 patients with regard to outcome and the presence or absence of detectable ethanol in the blood as determined in the emergency room demonstrated no difference in the severity of injury in those who had been drinking and those who had not. Mortality was significantly lower in those who had been drinking. There were no other significant differences in the two groups. The mechanism by which this occurs is not well understood but may be related to an augmentation of the catecholamine response normally seen after injury.

The management of splenic injury

Increased concern over the potential immunologic consequences of splenectomy has prompted surgeons to attempt salvage of traumatized spleens. We report a retrospective study of 172 consecutive patients with documented splenic injury treated over a 2-year period: 107 patients underwent splenectomy; 65 were managed without total splenectomy; 32 were not explored. The overall mortality rate was 27%; the overall complications were 30%, including a 13% incidence of post-splenectomy subphrenic abscess. The incidence of infectious complications after splenectomy was 36%, while the incidence in nonsplenectomized patients was 9%. The Injury Severity Scores (ISS) in the two groups were significantly different (p less than or equal to 0.05). When the group whose spleens were salvaged was compared to an equivalent group matched for ISS, age, and sex, there was no significant difference in sepsis rates (23% vs. 10.7%; 0.10 greater than or equal to p greater than or equal to 0.05). Survival in those with postinjury infectious complications was significantly improved in patients with a remaining spleen (p less than or equal to 0.01). Abdominal computerized tomography was used successfully as a method of following injured and repaired spleens in order to predict return to full activity.