Morpho-functional analysis of patient-derived xenografts reveals differential impact of gastric cancer and chemotherapy on the tumor ecosystem, affecting immune check point, metabolism, and sarcopenia

OBJECTIVES

Gastric cancer (GC) is an aggressive disease due to late diagnosis resulting from the lack of easy diagnostic tools, resistances toward immunotherapy (due to low PD-L1 expression), or chemotherapies (due to p53 mutations), and comorbidity factors, notably muscle atrophy. To improve our understanding of this complex pathology, we established patient-derived xenograft (PDX) models and characterized the tumor ecosystem using a morpho-functional approach combining high-resolution imaging with molecular analyses, regarding the expression of relevant therapeutic biomarkers and the presence of muscle atrophy.

MATERIALS AND METHODS

GC tissues samples were implanted in nude mice. Established PDX, treated with cisplatin or not, were imaged by magnetic resonance imaging (MRI) and analyzed for the expression of relevant biomarkers (p53, PD-L1, PD-1, HER-2, CDX2, CAIX, CD31, a-SAM) and by transcriptomics.

RESULTS

Three well-differentiated, one moderately and one poorly differentiated adenocarcinomas were established. All retained the architectural and histological features of their primary tumors. MRI allowed in-real-time evaluation of differences between PDX, in terms of substructure, post-therapeutic changes, and muscle atrophy. Immunohistochemistry showed differential expression of p53, HER-2, CDX2, a-SAM, PD-L1, PD-1, CAIX, and CD31 between models and upon cisplatin treatment. Transcriptomics revealed treatment-induced hypoxia and metabolic reprograming in the tumor microenvironment.

CONCLUSION

Our PDX models are representative for the heterogeneity and complexity of human tumors, with differences in structure, histology, muscle atrophy, and the different biomarkers making them valuable for the analyses of the impact of platinum drugs or new therapies on the tumor and its microenvironment.

Author Correction: Electric and antiferromagnetic chiral textures at multiferroic domain walls

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Electric and antiferromagnetic chiral textures at multiferroic domain walls

Chirality, a foundational concept throughout science, may arise at ferromagnetic domain walls¹ and in related objects such as skyrmions². However, chiral textures should also exist in other types of ferroic materials, such as antiferromagnets, for which theory predicts that they should move faster for lower power³, and ferroelectrics, where they should be extremely small and possess unusual topologies^4,5. Here, we report the concomitant observation of antiferromagnetic and electric chiral textures at domain walls in the room-temperature ferroelectric antiferromagnet BiFeO₃. Combining reciprocal and real-space characterization techniques, we reveal the presence of periodic chiral antiferromagnetic objects along the domain walls as well as a priori energetically unfavourable chiral ferroelectric domain walls. We discuss the mechanisms underlying their formation and their relevance for electrically controlled topological oxide electronics and spintronics.

The efficacy of 16S ribosomal DNA sequencing in the diagnosis of bacteria from blood, bone and synovial fluid samples of children with musculoskeletal infections

BACKGROUND

Musculoskeletal infections are among the most common bacterial infections in children leading to hospitalization, invasive procedures and prolonged antibiotic administration. Blood, synovial and sometimes tissue cultures are essential for the diagnosis and treatment of musculoskeletal infections; 16S ribosomal DNA (rDNA) sequencing is a novel diagnostic tool for the detection of bacteria.While the yield of 16S rDNA sequencing in synovial fluid was previously assessed, data regarding the efficacy of this method from blood samples or partially treated children with suspected musculoskeletal infections is lacking.In this study we assessed the yield of 16S rDNA sequencing in blood, bone and synovial samples of children with musculoskeletal infections.

METHODS

Blood, synovial and bone samples were collected from children with suspected musculoskeletal infections and analyzed for the presence of 16S rDNA, the results were then compared with the benchmark microbial cultures.

RESULTS

During the study period, 41 children (18 boys and 23 girls) with suspected acute musculoskeletal infection were enrolled. A positive blood culture was found in 6/31 cases (19.4%) with methicillin-susceptible Staphylococcus aureus being the most commonly isolated bacterium. No significant 16S rDNA detection in blood samples was recorded.Synovial fluid culture was positive in 6/28 samples (21%), Kingella kingae being the most common pathogen. When using the 16S rDNA sequencing method, the rate of positive results in synovial fluid was higher with bacterial detection in 12/23 (52%) samples. The 16S rDNA sequencing method was also able to identify pathogens in samples taken from partially treated children where cultures were negative with 16S rDNA detection in 5/5 samples.

CONCLUSION

Although 16S rDNA sequencing may increase the yield of bacterial detection in synovial samples of patients with musculoskeletal infections, there is no benefit from applying this method on blood samples. The 16S rDNA sequencing method may be particularly beneficial when antibiotic treatment was started prior to synovial fluid sampling.

LEVEL OF EVIDENCE

Level-II diagnostic study.

Prognostic factors of hemorrhagic complications after oxaliplatin-based hyperthermic intraperitoneal chemotherapy: Toward routine preoperative dosage of Von Willebrand factor?

BACKGROUND

Oxaliplatin-based hyperthermic intraperitoneal chemotherapy (HIPEC-ox) induces specific morbidity with hemorrhagic complications (HC). The aim of this study was to identify preoperative, intraoperative and postoperative HC predictive factors after HIPEC-ox.

METHODS

A prospective single center study that included all consecutive patients treated with curative-intent HIPEC-ox, whatever the origin of peritoneal disease, was conducted. All patients underwent systematic blood tests exploring primary hemostasis and endothelial activation before surgical incision (D0) and on postoperative days 2 (POD2) and 5 (POD5).

RESULTS

Between May 2012 and August 2015, 47 patients were enrolled in the study. The overall HC rate was 38%. Major morbidity was significantly higher in patients with HC. Patients presenting HC were significantly more often affected with pseudomyxoma peritonei and had less preoperative chemotherapy. Multivariate analysis showed that a higher plasmatic level of Von Willebrand factor antigen at D0 (D0 VWF:Ag) was a protective predictive factor for HC (p = 0.049, HR: 0.97 CI 95% [0.94-1.00]). A D0 VWF:Ag level below 138% had a sensitivity of 87.5%, a specificity of 67% and an area under the curve of 80.3% (CI 95% [66.5-94], p < 0.01) for predicting HC.

CONCLUSIONS

Through the identification of prognostic factors, this study highlighted a subgroup of patients with low risk of HC after HIPEC-ox. Based on these results, we propose a routine preoperative dosage of VWF that would help the surgeon to select the most suitable patients for HIPEC-ox.

A Navigated Mechatronic System with Haptic Features to Assist in Surgical Interventions

OBJECTIVE

In orthopaedic surgery, the development of new computer-based technologies such as navigation systems and robotics will facilitate more precise, reproducible results in surgical interventions. There are already commercial systems available for clinical use, though these still have some limitations and drawbacks. This paper presents an alternative approach to a universal modular surgical assistant system for supporting less or minimally invasive surgery.

MATERIALS AND METHODS

The position of a mechatronic arm, which is part of the system, is controlled by a navigation system so that small patient movements are automatically detected and compensated for in real time. Thus, the optimal tool position can be constantly maintained without the need for rigid bone or patient fixation. Furthermore, a force control mode of the mechatronic assistant system, based on a force-torque sensor, not only increases safety during surgical interventions but also facilitates hand-driven direct positioning of the arm.

RESULTS

A prototype has been successfully tested in clinical applications at the Orthopadische Universitätsklinik Frankfurt. For the first time worldwide, implantation of the cup prosthesis in total hip replacement surgery has been carried out with the assistance of a mechatronic arm. According to measurements by the digitizing system, operating tool angle deviation remained below 0.5 degrees, relative to the preoperative planning.

CONCLUSION

The presented approach to a new kind of surgical mechatronic assistance system supports the surgeon as needed by optimal positioning of the surgical instruments. Due to its modular design, it is applicable to a wide range of tasks in surgical interventions, e.g., endoscope guidance, bone preparation, etc.

Different effects of the Cdx1 and Cdx2 homeobox genes in a murine model of intestinal inflammation

AIMS

The CDX1 and CDX2 homeoproteins are intestine-specific transcription factors regulating homeostasis. We investigated their relevance in experimentally-induced intestinal inflammation.

METHODS

The response to intestinal inflammation induced by dextran sodium sulfate (DSS) was compared in wild type, Cdx1(-/-) and Cdx2(+/-) mice. Intestinal permeability was determined in wild type and Cdx2(+/-) mice. Protein-protein interactions were investigated by co-immunoprecipitation and GST-pulldown, and their functional consequences were assessed using Luciferase reporter systems.

RESULTS

Heterozygous Cdx2(+/-) mice, but not Cdx1(-/-) mice, were hypersensitive to DSS-induced acute inflammation as all these mice showed blood in the stools at day 1 of DSS treatment. Hypersensitivity was associated to a 50% higher intestinal permeability. In Cdx2(+/-) mice, the colonic epithelium was repaired during the week after the end of DSS treatment, whereas two weeks were required for wild type animals. Subsequently, no colonic tumour was observed in Cdx2(+/-) mice subjected to 5 repeated cycles of DSS, in contrast to the 2.7 tumours found per wild type mouse. Based on the fact that Smad3(+/-) mice, like Cdx2(+/-) mice, better repair the damaged intestinal epithelium, we found that the CDX2 protein interacts with SMAD3, independently of SMAD4, resulting in a 5-fold stimulation of SMAD3 transcriptional activity. CDX1 also interacted with SMAD3 but it inhibited by 10-fold the SMAD3/SMAD4-dependent transcription.

CONCLUSION

The Cdx1 and Cdx2 homeobox genes have distinct effects on the outcome of a pro-inflammatory challenge. This is mirrored by different functional interactions of the CDX1 and CDX2 proteins with SMAD3, a major element of the TGFbeta signalling pathway.

Occupational risks for adenocarcinoma of the nasal cavity and paranasal sinuses in the German wood industry

OBJECTIVES

To examine the risk of wood dust and chemical exposures for adenocarcinoma of the nasal cavity and paranasal sinuses (ADCN) among German wood workers.

METHODS

An industry-based case-control study with 86 male ADCN cases and 204 controls was conducted in the German wood-working industries. Cumulative and average wood-dust exposure was quantified with a job-exposure matrix based on wood-dust measurements at recent and historical workplaces. Probabilities of exposure to wood preservatives, stains, varnishes, and formaldehyde were semi-quantitatively rated. Odds ratios and 95% confidence intervals were calculated with logistic regression analysis conditional on age and adjusted for smoking and other factors. For estimating the risks of either wood dust or chemical additives, the authors additionally adjusted for the corresponding co-exposure.

RESULTS

ADCN occurred relatively more frequently among wood workers that had ever worked as cabinet makers or joiners (OR 2.96, 95% CI 1.46 to 6.01) than as saw millers (OR 0.15, 95% CI 0.03 to 0.68). Average exposure to inhalable wood dust >/=5 mg/m(3) was associated with a high risk (OR 48.47, 95% CI 13.30 to 176.63) compared to levels below 3.5 mg/m(3). Assuming 40 years of exposure under these concentrations, the corresponding OR was 4.20 (95% CI 1.69 to 10.43). Exposure between 3.5 and 5 mg/m(3) was also found to pose a risk (OR 10.54, 95% CI 3.34 to 33.27). Exposure to pigment stains before 1970 was associated with an increased risk (OR 3.03; 95% CI 1.11 to 8.26). No significant associations were estimated for wood preservatives, varnishes, and formaldehyde.

CONCLUSIONS

The authors found an elevated ADCN risk for exposure to inhalable wood dust above 3.5 mg/m(3). The rareness of the disease does not allow the exclusion of risk below that concentration. For pigment stains, there is evidence for an association of historical exposure with the development of ADCN in German wood workers.

Multiple neurotoxic stresses converge on MDMX proteolysis to cause neuronal apoptosis

MDMX has been shown to modulate p53 in dividing cells after DNA damage. In this study, we investigated the role of MDMX in primary cultures of neurons undergoing cell death. We found that DNA damage, but also membrane-initiated apoptotic stresses (glutamate receptor; Amyloid beta precursor) or survival factor deprivation downregulated MDMX protein levels. Forced downregulation of murine double minute X (MDMX) by shRNA induced apoptosis suggesting that MDMX is required for survival in neurons. Protease inhibitors prevented the loss of MDMX after neurotoxic treatments, indicating a regulation of protein stability. Some, but not all, neurotoxic stresses induced phosphorylation of MDMX at serine 367, further supporting regulation at the protein level. Interestingly, we found that depending on the stimulus either p53 or E2F1 was induced, but overexpression of MDMX inhibited the transcriptional activity of both proapoptotic factors, and maintained neuronal viability upon neurotoxic stresses. Taken together, our data show that MDMX is an antiapoptotic factor in neurons, whose degradation is induced by various stresses and allows activation of p53 and E2F-1 during neuronal apoptosis.

Sprouty2 inhibits BDNF-induced signaling and modulates neuronal differentiation and survival

Sprouty (Spry) proteins are ligand-inducible inhibitors of receptor tyrosine kinases-dependent signaling pathways, which control various biological processes, including proliferation, differentiation and survival. Here, we investigated the regulation and the role of Spry2 in cells of the central nervous system (CNS). In primary cultures of immature neurons, the neurotrophic factor BDNF (brain-derived neurotrophic factor) regulates spry2 expression. We identified the transcription factors CREB and SP1 as important regulators of the BDNF activation of the spry2 promoter. In immature neurons, we show that overexpression of wild-type Spry2 blocks neurite formation and neurofilament light chain expression, whereas inhibition of Spry2 by a dominant-negative mutant or small interfering RNA favors sprouting of multiple neurites. In mature neurons that exhibit an extensive neurite network, spry2 expression is sustained by BDNF and is downregulated during neuronal apoptosis. Interestingly, in these differentiated neurons, overexpression of Spry2 induces neuronal cell death, whereas its inhibition favors neuronal survival. Together, our results imply that Spry2 is involved in the development of the CNS by inhibiting both neuronal differentiation and survival through a negative-feedback loop that downregulates neurotrophic factors-driven signaling pathways.

The intestine-specific homeobox gene Cdx2 decreases mobility and antagonizes dissemination of colon cancer cells

The gravity of colorectal cancer is mainly due to the capacity of tumor cells to migrate out of the tumor mass to invade the stroma and disseminate as metastases. The acquisition of a migratory phenotype also occurs during wound healing. Here, we show that several features characterizing invasive colon tumor cells are shared by migrating cells during wound repair in vitro. In particular, the expression of the intestine-specific transcription factor Cdx2, a key gene for intestinal identity downregulated in invasive cancer cells, is reduced during wound healing in vitro. Transcription factors involved in epithelial-mesenchymal transition such as Snail and Slug are upregulated during wound healing and are able to repress Cdx2 transcription. In vitro, forced expression of Cdx2 in human colon cancer cell lines retarded wound repair and reduced migration, whereas inhibition of Cdx2 expression by RNA interference enhanced migration. In vivo, forced expression of Cdx2 opposed tumor cells spreading in nude mice xenografted at three different sites. These data provide evidence that Cdx2 antagonizes the process of tumor cell dissemination, and they suggest that this homeobox gene might represent a new therapeutic target against metastatic spreading of colon cancer.

Inhaled nitric oxide for the postoperative management of pulmonary hypertension in infants and children with congenital heart disease

BACKGROUND

Nitric oxide (NO) is a prevalent molecule in the human body responsible for many physiologic activities including pulmonary vasodilation. An exogenous, inhaled form (iNO) exists that mimics this action without directly affecting systemic blood pressure. This therapy has been implemented in the treatment of pulmonary hypertension. This review examines the efficacy of iNO in the postoperative management of infants and children with congenital heart disease.

OBJECTIVES

To compare the effects of postoperative iNO versus placebo and/or conventional management on infants and children with congenital heart disease. The primary outcome was mortality, while secondary outcomes included length of hospital stay, assessment of neurodevelopmental disability, number of pulmonary hypertensive crises (PHTC), changes in haemodynamics including mean pulmonary arterial pressure (MPAP), mean arterial pressure (MAP), and heart rate (HR), changes in oxygenation measured as the ratio PaO2:FiO2, and measurement of maximum methaemoglobin level as a marker of toxicity.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 3, 2004), MEDLINE (1966 to 2004), and EMBASE (1980 to 2004). We included abstracts and all languages.

SELECTION CRITERIA

We included randomized and quasi-randomized controlled trials comparing iNO with placebo and conventional management, or both. Trials included only children with congenital heart disease requiring surgery and complicated by pulmonary hypertension.

DATA COLLECTION AND ANALYSIS

Data were collected on mortality, number of PHTC, changes in MPAP, MAP, HR, and PaO2:FiO2, and maximum methaemoglobin level, while data on long-term mortality, neurodevelopmental disability, and length of hospital stay were unavailable. We performed subgroup analysis by age and method of control. We performed sensitivity analysis using studies of highest methodologic quality.

MAIN RESULTS

We included four randomized trials. We observed no differences between groups with respect to mortality (P = 0.50), PHTC (P = 0.79), change in MPAP (P = 0.16), MAP (P = 0.40), HR (P = 1.00), or PaO2:FiO2 (P = 0.46). There was a significant reduction in MPAP in the subgroup of patients from birth to three months (P = 0.005), although this finding was based on a small number of patients (N = 23).

AUTHORS' CONCLUSIONS

We observed no differences with the use of iNO as compared with control in the majority of outcomes reviewed. No data were available for analysis with respect to several clinical outcomes including long-term mortality and neurodevelopmental outcome. We found it difficult to draw valid conclusions because of concerns regarding methodologic quality, bias, sample size, and heterogeneity.

Mammalian sprouty proteins inhibit cell growth and differentiation by preventing ras activation

Sprouty was genetically identified as an antagonist of fibroblast growth factor signaling during tracheal branching in Drosophila. In this study, we provide a functional characterization of mammalian Sprouty1 and Sprouty2. Sprouty1 and Sprouty2 inhibited events downstream of multiple receptor tyrosine kinases and regulated both cell proliferation and differentiation. Using NIH3T3 cell lines conditionally expressing Sprouty1 or Sprouty2, we found that these proteins specifically inhibit the Ras/Raf/MAP kinase pathway by preventing Ras activation. In contrast, activation of the phosphatidylinositol 3-kinase pathway was not affected by Sprouty1 or Sprouty2. We further showed that Sprouty1 and Sprouty2 do no prevent the formation of a SNT.Grb2.Sos complex upon fibroblast growth factor stimulation, yet block Ras activation. Taken together, these results establish mammalian Sprouty proteins as important negative regulators of growth factor signaling and suggest that Sprouty proteins act downstream of the Grb2.Sos complex to selectively uncouple growth factor signals from Ras activation and the MAP Kinase pathway.

Is there a role for antenatal TRH therapy for the prevention of neonatal lung disease?

Unfortunately, surfactant therapy is not routinely available to infants in some parts of the world because of its cost. It is the hypothesis of this article that in situations where surfactant is not available, there may be a role for antenatal thyrotropin-releasing hormone (TRH) plus glucocorticoid therapy. Data from randomized clinical trials, which compared therapy with antenatal glucocorticoid plus TRH to that with glucocorticoid alone were extracted and subjected to meta-analysis. The trials that incorporated surfactant therapy were analyzed separately from those in which surfactant was not used. In addition, because surfactant therapy was only available to some patients in the Australian ACTOBAT trial, each group analysis was performed with and without the ACTOBAT data. A characteristic of the earlier presurfactant trials is that few were designed for "intention to treat" analysis. In most of these studies, it was decided a priori to include babies who delivered within a specified time period after hormone therapy. The addition of TRH did not decrease respiratory distress syndrome in those trials in which surfactant therapy was used. In the presurfactant trials, respiratory distress syndrome was significantly decreased when "intention to treat" data were examined, as well as in those infants who delivered between 1 and 10 days after maternal therapy. There was also a significant decrease in oxygen dependency at 28 days after birth, and in oxygen dependency or death at this time, in those infants who delivered 1 to 10 days after treatment. Antenatal TRH had no significant effect of on neonatal complications such as air leak, intraventricular hemmorhage, patent ductus arteriosus, retinopathy of prematurity, or necrotizing enterocolitis. However, TRH did produce transient suppression of the pituitary thyroid axis. There were also a variety of transient complications in the mothers, including nausea, vomiting or flushing, light-headed feeling, and increased blood pressure. The authors conclude that the implementation of appropriate antenatal glucocorticoid treatment is the first priority. Once this has been established, the data presented here suggest that addition of antenatal TRH should be considered in those situations where surfactant is not available.

Organization of immature human immunodeficiency virus type 1

Immature retrovirus particles contain radially arranged Gag polyproteins in which the N termini lie at the membrane and the C termini extend toward the particle's center. We related image features to the polyprotein domain structure by combining mutagenesis with cryoelectron microscopy and image analysis. The matrix (MA) domain appears as a thin layer tightly associated with the inner face of the viral membrane, separated from the capsid (CA) layer by a low-density region corresponding to its C terminus. Deletion of the entire p6 domain has no effect on the width or spacing of the density layers, suggesting that p6 is not ordered in immature human immunodeficiency virus type 1 (HIV-1). In vitro assembly of a recombinant Gag polyprotein containing only capsid (CA) and nucleocapsid (NC) domains results in the formation of nonenveloped spherical particles which display two layers with density matching that of the CA-NC portion of immature HIV-1 Gag particles. Authentic, immature HIV-1 displays additional surface features and an increased density between the lipid bilayers which reflect the presence of gp41. The other internal features match those of virus-like particles.

Recent advances in respiratory care of the term neonate

Persistent pulmonary hypertension is a major cause of morbidity and mortality in the term and near-term infant. Management of this condition, which is characterized by respiratory distress and cyanosis, has been greatly enhanced by inhaled nitric oxide (NO) therapy. The following treatment regime is suggested: Conventional ventilation should be used initially, and hyperventilation should be avoided. Surfactant should be administered early, preferably within 6 hours of diagnosis. If conventional ventilation fails, the next step is high-frequency ventilation or inhaled NO. Some infants who do not respond to inhaled NO when administered by conventional ventilation will respond to NO delivery via a high-frequency ventilator. If all of these therapies fail, extracorporeal membrane oxygenation (ECMO) should be considered. By the use of this approach, the mortality from PPH has been considerably reduced, and concerns today relate primarily to morbidity, particularly long-term neurologic outcome and chronic lung disease resulting from ventilation and barotrauma.

E-cadherin is a WT1 target gene

The WT1 tumor suppressor gene encodes a transcription factor that can activate and repress gene expression. Transcriptional targets relevant for the growth suppression functions of WT1 are poorly understood. We found that mesenchymal NIH 3T3 fibroblasts stably expressing WT1 exhibit growth suppression and features of epithelial differentiation including up-regulation of E-cadherin mRNA. Acute expression of WT1 in NIH 3T3 fibroblasts after retroviral infection induced murine E-cadherin expression. In transient transfection experiments, the human and murine E-cadherin promoters were activated by co-expression of WT1. E-cadherin promoter activity was increased in cells overexpressing WT1 and was blocked by a dominant negative form of WT1. WT1 activated the murine E-cadherin promoter through a conserved GC-rich sequence similar to an EGR-1 binding site as well as through a CAAT box sequence. WT1 produced in vitro or derived from nuclear extracts bound to the WT1-response element within the murine E-cadherin promoter, but not the CAAT box. E-cadherin, a gene important in epithelial differentiation and neoplastic transformation, represents a downstream target gene that links the roles of the WT1 in differentiation and growth control.

Indoor determinants of Der p 1 and Der f 1 concentrations in house dust are different

BACKGROUND

Exposure to mite allergens is a major risk factor for sensitization and the development of asthma. Der p 1 and Der f 1 content in homes and probably the proportion of both antigens is highly variable even in the same geographical area.

OBJECTIVE

We investigated specific indoor determinants of Der p 1 and Der f 1 concentrations in house dust of two German cities, Erfurt and Hamburg (n = 405 homes).

METHODS

Mite allergen levels were determined using monoclonal antibodies against Der p 1 and Der f 1 by the ELISA method. Indoor relative humidity and temperature were monitored continuously in the homes over 1 week. The characteristics of homes and occupants were assessed by questionnaire to obtain information on factors which may have an impact on the mite antigen concentration in house dust. These determinants were studied by multivariate regression analysis.

RESULTS

The correlation between concentrations of Der p 1 and Der f 1 inside the homes was weak (r = 0.29-0.35), indicating that different determinants are relevant. Concentrations of the allergens were significantly higher on lower floors (ratios 2-8 times, Der p 1, Der f 1), on old mattresses (ratios 3-13 times, Der p 1, Der f 1), in post-war buildings (ratio 6 times, Der p 1), for non-central heating (ratio 2 times, Der p 1), for old carpets (ratio 3 times, Der p 1) and for the presence of a dog in the house (ratio 3 times, Der f 1). Furthermore, mite concentration increases with raising relative humidity (ratio 1.03 per 1%, Der p 1) and with decreasing temperature (ratio 0.86 per 1 degrees C, Der p 1) indoors.

CONCLUSION

Both Der p 1 and Der f 1 concentrations should be measured in house dust, since they are only weakly correlated and have different determinants.

A conformational switch controlling HIV-1 morphogenesis

Assembly of infectious human immunodeficiency virus type 1 (HIV-1) proceeds in two steps. Initially, an immature virus with a spherical capsid shell consisting of uncleaved Gag polyproteins is formed. Extracellular proteolytic maturation causes rearrangement of the inner virion structure, leading to the conical capsid of the infectious virus. Using an in vitro assembly system, we show that the same HIV-1 Gag-derived protein can form spherical particles, virtually indistinguishable from immature HIV-1 capsids, as well as tubular or conical particles, resembling the mature core. The assembly phenotype could be correlated with differential binding of the protein to monoclonal antibodies recognizing epitopes in the HIV-1 capsid protein (CA), suggesting distinct conformations of this domain. Only tubular and conical particles were observed when the protein lacked spacer peptide SP1 at the C-terminus of CA, indicating that SP1 may act as a molecular switch, whose presence determines spherical capsid formation, while its cleavage leads to maturation.

Stoichiometry of potassium channel opener action

Potassium channel openers (KCOs; e.g., P1075, pinacidil) exert their effects on excitable cells by opening ATP-sensitive potassium channels. These channels are heteromultimers composed with a 4:4 stoichiometry of an inwardly rectifying K(+) channel subunit plus a regulatory subunit comprising the receptor sites for hypoglycemic sulfonylureas and KCOs (a sulfonylurea receptor). To elucidate stoichiometry of KCO action, we analyzed P1075 sensitivity of channels coassembled from sulfonylurea receptor isoforms with high or low P1075 affinity. Concentration activation curves for cDNA ratios of 1:1 or 1:10 resembled those for channel opening resulting from interaction with a single site, whereas models for activation requiring occupation of two, three, or four sites were incongruous. We conclude KCO-induced channel activation to be mediated by interaction with a single binding site per tetradimeric complex.

Allergens in house-dust samples in Germany: results of an East-West German comparison

The background of this study is the finding of several studies that the frequency of respiratory allergies was significantly higher in the former West Germany than the former East Germany. The present study investigated the levels of allergens of house-dust mite (Der p 1 and Der f 1), cat (Fel d 1), and cockroach (Bla g 2) in the household dust of 201 homes in Hamburg (West Germany) and 204 homes in Erfurt (East Germany), and examined the factors that affect these levels. The characteristics of homes were assessed by a questionnaire. The allergen levels were studied in dust from living rooms (LR), bedrooms (BR), and mattresses (MA). We detected in samples from Hamburg significantly higher allergen concentrations than in Erfurt: three times higher Der p 1, five times higher Der f 1, and three times higher Fel d 1. For Bla g 2, no comparison was possible because the concentrations were below the detection limit in 93% of the samples. Most of the differences could be explained by differences in housing and living characteristics between both cities. The mean ratio of Der p 1 levels in mattress dust between Hamburg and Erfurt decreased from 4.1 to 1.54 (NS) after adjustment for season, building material, age of the house, story of the dwelling, type of heating, age of carpet/mattress, presence of dogs, and indoor climate (temperature, humidity). The mean ratio of Der f 1 levels decreased from 6.9 to 2.78 (P<0.05) after adjustment for these factors. The mean ratio for Fel d 1 in mattress dust decreased fom 4.03 to 1.65 (P<0.05) after adjustment for season, building material, story of dwelling, size of dwelling, ventilation, cleaning routines, and pets. A similar reduction was seen for floor dust (LR plus BR). Our results indicate that the differences between the concentrations of mite and cat allergens found in Hamburg and Erfurt are explicable mainly, but not completely, by different building characteristics (age of houses, building material, story, and size of the dwelling) which affected the indoor climate, as well as by differences in other individual living habits (keeping of pets, age of carpets or mattresses, and cleaning routines).

Identification of the Potassium Channel Opener Site on Sulfonylurea Receptors

Diversity of sulfonylurea receptor (SUR) subunits underlies tissue specific pharmacology of K(ATP) channels, which represent critical regulators of electrical activity in numerous cells. Notably, the neuronal/pancreatic beta-cell receptor, SUR1, imparts high sensitivity to hypoglycemic sulfonylureas (SUs; e.g. glibenclamide) and low to potassium channel openers (KCOs; e.g. P1075), whereas the opposite drug sensitivities are conferred by cardiovascular receptors, SUR2A and SUR2B. By exchanging domains between SUR1 and SUR2B, we identify two regions (KCO I: Thr(1059)-Leu(1087) and KCO II: Arg(1218)-Asn(1320); rat SUR2 numbering) within the second set of transmembrane domains (TMDII) as critical for KCO binding. Swapping both regions reconstitutes KCO affinities and sensitivities of the donor SUR isoform. High glibenclamide affinity of SUR1 is not reduced by transfer of KCO I plus II from SUR2B, demonstrating that high SU and KCO affinity can coexist in the same SUR molecule. Consistently, high SU affinity was imparted on SUR2B by substituting the region separating KCO I and II (Ile(1088)-Val(1217)) with the corresponding domain of SUR1. We infer the receptor sites for KCOs and SUs to be closely associated within a regulatory domain (Thr(1059)-Asn(1320)) in TMDII of SURs.

Dorsal-B, a splice variant of the Drosophila factor Dorsal, is a novel Rel/NF-kappaB transcriptional activator

The Drosophila transcription factor Dorsal, a member of the Rel/NF-kappaB family of proteins, plays a key role in the establishment of dorsoventral polarity in the early embryo and is also involved in the immune response. Here, we present evidence that the primary transcript of dorsal can be alternatively spliced, generating Dorsal-B, a new Rel/NF-kappaB family member. Dorsal and Dorsal-B are identical in the N-terminal region, which comprises both a DNA-binding domain and a dimerization domain. However, Dorsal-B lacks the nuclear localization signal located at the end of the Rel domain of Dorsal and is totally divergent in the C-terminal portion. Although Dorsal-B by itself is not able to induce the expression of a kappaB-controlled Luciferase reporter gene, we demonstrate that its C-terminal portion has transactivating properties. Analysis of the dorsal-B expression pattern indicates that the splicing is tissue-specific and excludes a putative role in early embryogenesis. However, dorsal-B synthesis is enhanced upon septic injury, and this challenge induces a nuclear accumulation of the protein in fat body cells suggesting that it may be involved in the immune response.

Potassium channel openers require ATP to bind to and act through sulfonylurea receptors

KATP channels are composed of a small inwardly rectifying K+ channel subunit, either KIR6.1 or KIR6.2, plus a sulfonylurea receptor, SUR1 or SUR2 (A or B), which belong to the ATP-binding cassette superfamily. SUR1/KIR6.2 reconstitute the neuronal/pancreatic beta-cell channel, whereas SUR2A/KIR6.2 and SUR2B/KIR6.1 (or KIR6.2) are proposed to reconstitute the cardiac and the vascular-smooth-muscle-type KATP channels, respectively. We report that potassium channel openers (KCOs) bind to and act through SURs and that binding to SUR1, SUR2A and SUR2B requires ATP. Non-hydrolysable ATP-analogues do not support binding, and Mg2+ or Mn2+ are required. Point mutations in the Walker A motifs or linker regions of both nucleotide-binding folds (NBFs) abolish or weaken [3H]P1075 binding to SUR2B, rendering reconstituted SUR2B/KIR6.2 channels insensitive towards KCOs. The C-terminus of SUR affects KCO affinity with SUR2B approximately SUR1 > SUR2A. KCOs belonging to different structural classes inhibited specific [3H]P1075 binding to SUR2B in a monophasic manner, with the exception of minoxidil sulfate, which induced a biphasic displacement. The affinities of KCO binding to SUR2B were 3.5-8-fold higher than their potencies for activation of SUR2B/KIR6.2 channels. The results establish that SURs are the KCO receptors of KATP channels and suggest that KCO binding requires a conformational change induced by ATP hydrolysis in both NBFs.

Fetal lung mRNA levels of Hox genes are differentially altered by maternal diabetes and butyrate in rats

Diabetes is known to be associated with delayed lung development in humans and in experimental animals. This includes delayed expression of surfactant apoproteins. An important component of the metabolic abnormalities in diabetes is elevated levels of analogs of butyric acid, and the effects of diabetes on surfactant apoproteins can be reproduced by exposure of fetal rat lung explants to butyrate. Dexamethasone has the opposite effects on lung development. In humans, antenatal exposure to dexamethasone results in a lower incidence of RDS, whereas in experimental animals, dexamethasone increases the expression of surfactant apoproteins. A subset of Hox genes are expressed in developing lung, and their level of expression decreases with advancing gestation. We hypothesized that: 1) lungs of fetuses of rats with streptozotocin-induced diabetes would have altered levels of expression of Hox genes, 2) the effect would be mediated in part through elevated levels of butyrate, and 3) dexamethasone would reverse the effect. We tested our hypotheses in vivo using fetuses from streptozotocin-treated rats and in vitro by treating lung explants from normal rats with sodium butyrate. Streptozotocin treatment increased expression of Hoxb-5 at 18 d of gestation, but did not affect Hoxa-5 expression. This was associated with a 20-fold increase in alpha-aminobutyrate levels. Dexamethasone tended to reverse this effect. In contrast, butyrate treatment of explants decreased the expression of Hoxa-5 and Hoxb-5. We conclude that diabetes alters expression of Hox genes, but that the effect of butyrate on lung development, and in particular on surfactant apoprotein expression, is independent of its effects on Hox genes.

N-Terminal extension of human immunodeficiency virus capsid protein converts the in vitro assembly phenotype from tubular to spherical particles

Expression of retroviral Gag polyproteins is sufficient for morphogenesis of virus-like particles with a spherical immature protein shell. Proteolytic cleavage of Gag into the matrix (MA), capsid (CA), nucleocapsid (NC), and p6 domains (in the case of human immunodeficiency virus [HIV]) leads to condensation to the mature cone-shaped core. We have analyzed the formation of spherical or cylindrical particles on in vitro assembly of purified HIV proteins or inside Escherichia coli cells. CA protein alone yielded cylindrical particles, while all N-terminal extensions of CA abolished cylinder formation. Spherical particles with heterogeneous diameters or amorphous protein aggregates were observed instead. Extending CA by 5 amino acids was sufficient to convert the assembly phenotype to spherical particles. Sequences C-terminal of CA were not required for sphere formation. Proteolytic cleavage of N-terminally extended CA proteins prior to in vitro assembly led to the formation of cylindrical particles, while proteolysis of in vitro assembly products caused disruption of spheres but not formation of cylinders. In vitro assembly of CA and extended CA proteins in the presence of cyclophilin A (CypA) at a CA-to-CypA molar ratio of 10:1 yielded significantly longer cylinders and heterogeneous spheres, while higher concentrations of CypA completely disrupted particle formation. We conclude that the spherical shape of immature HIV particles is determined by the presence of an N-terminal extension on the CA domain and that core condensation during virion maturation requires the liberation of the N terminus of CA.

In vitro assembly properties of purified bacterially expressed capsid proteins of human immunodeficiency virus

The Gag polyprotein of retroviruses is sufficient for assembly and budding of virus-like particles from the host cell. In the case of human immunodeficiency virus (HIV), Gag contains the domains matrix, capsid (CA), nucleocapsid (NC) and p6 which are separated by the viral proteinase inside the nascent virion, leading to morphological maturation to yield an infectious virus. In the mature virus, CA forms a capsid shell surrounding the ribonucleoprotein core consisting of NC and the genomic RNA. To define requirements for particle assembly and functional contributions of individual domains, we expressed domains of HIV Gag in Escherichia coli and purified the products to near homogeneity. In vitro assembly of CA, with or without the C-terminally adjacent spacer peptide, yielded tubular structures with a diameter of approximately 55 nm and heterogeneous length. Efficient particle formation required high protein concentration, high salt and neutral to alkaline pH. In contrast, in vitro assembly of CA-NC occurred at a 20-fold lower protein concentration and in low salt, but required addition of RNA. These results suggest that hydrophobic interactions of capsid proteins are sufficient for particle formation while the RNA-binding nucleocapsid domain may concentrate and align structural proteins on the viral genome.

Identification of endogenous Des-Arg9-[Hyp3]-bradykinin in human plasma with post-source-decay matrix-assisted laser desorption/ionization mass spectrometry

In the present study, the purification and sequence analysis of a peptide extracted from human plasma is described. After three chromatographic steps in one of the plasma fractions, a molecular mass of 920 Da was determined with matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analysis. Further analysis with post-source-decay (PSD)-MALDI-MS revealed an amino acid sequence arg-pro(pro-gly+16)-phe-ser-pro-phe. With the data given from the spectrum, it was impossible to clarify the partial sequence (pro-gly+16). A comparison with a data base suggested that the sequence is very similar to des-arg9bradykinin (arg-pro-pro-gly-phe-ser-pro-phe). But many fragment masses, including the mass of the parent ion of the unknown peptide, are 16 Da larger than the corresponding fragment masses of des-arg9-bradykinin. The interpretation of the fragment pattern does not allow determination of the position of the amino acid that is 16 Da larger. With automated Edman sequence analysis of the fraction of interest, three more major component peptides in this fraction were observed, which were not detected with MALDI-MS. Nevertheless, with the help of the Edman sequence data it was possible to identify the unknown amino acid in the PSD-MALDI-MS sequence as hydroxyproline at the third position. In conclusion, the existence of des-arg9[hyp3]-bradykinin (arg-pro-hyp-gly-phe-ser-pro-phe) in human plasma is described. Furthermore, the study demonstrates that PSD-MALDI-MS and automated Edman sequence analysis complement each other if single unknown peptides from mixtures are to be sequenced.

Inhaled nitric oxide and persistent pulmonary hypertension of the newborn. The Inhaled Nitric Oxide Study Group

BACKGROUND

Persistent pulmonary hypertension of the newborn causes systemic arterial hypoxemia because of increased pulmonary vascular resistance and right-to-left shunting of deoxygenated blood. Inhaled nitric oxide decreases pulmonary vascular resistance in newborns. We studied whether inhaled nitric oxide decreases severe hypoxemia in infants with persistent pulmonary hypertension.

METHODS

In a prospective, multicenter study, 58 full-term infants with severe hypoxemia and persistent pulmonary hypertension were randomly assigned to breathe either a control gas (nitrogen) or nitric oxide (80 parts per million), mixed with oxygen from a ventilator. If oxygenation increased after 20 minutes and systemic blood pressure did not decrease, the treatment was considered successful and was continued at lower concentrations. Otherwise, it was discontinued and alternative therapies, including extracorporeal membrane oxygenation, were used.

RESULTS

Inhaled nitric oxide successfully doubled systemic oxygenation in 16 of 30 infants (53 percent), whereas conventional therapy without inhaled nitric oxide increased oxygenation in only 2 of 28 infants (7 percent). Long-term therapy with inhaled nitric oxide sustained systemic oxygenation in 75 percent of the infants who had initial improvement. Extracorporeal membrane oxygenation was required in 71 percent of the control group and 40 percent of the nitric oxide group (P=0.02). The number of deaths was similar in the two groups. Inhaled nitric oxide did not cause systemic hypotension or increase methemoglobin levels.

CONCLUSIONS

Inhaled nitric oxide improves systemic oxygenation in infants with persistent pulmonary hypertension and may reduce the need for more invasive treatments.

Retinoic acid increases surfactant protein mRNA in fetal rat lung in culture

Retinoic acid has both early or immediate (within hours) and late (after days) effects on gene expression. We studied the early effects of retinoic acid on the surfactant protein (SP) genes. Exposure of fetal rat lung explants to all trans-retinoic acid for 4 h resulted in a significant dose-dependent increase in SP-A, -B, and -C mRNA with markedly different dose-response characteristics. The maximal (2.5x) increase in SP-A mRNA was observed with 10(-10) M retinoic acid, whereas treatment with 10(-5) M resulted in a tendency to decreased levels. In contrast, maximal stimulation of SP-C (6x) was noted at 10(-5) M retinoic acid and that of SP-B (2x) at 10(-7) to 10(-5) M retinoic acid. Similar differences in the dose-response characteristics of SP-A and SP-C were observed with 9-cis-retinoic acid. A retinoic acid response element consensus sequence was identified in the rat SP-A gene; we hypothesize that retinoic acid-receptor complexes act directly on the SP-A gene via this response element.

Immune factor Gambif1, a new rel family member from the human malaria vector, Anopheles gambiae

A novel rel family member, Gambif1 (gambiae immune factor 1), has been cloned from the human malaria vector, Anopheles gambiae, and shown to be most similar to Drosophila Dorsal and Dif. Gambif1 protein is translocated to the nucleus in fat body cells in response to bacterial challenge, although the mRNA is present at low levels at all developmental stages and is not induced by infection. DNA binding activity to the kappaB-like sites in the A.gambiae Defensin and the Drosophila Diptericin and Cecropin promoters is also induced in larval nuclear extracts following infection. Gambif1 has the ability to bind to kappaB-like sites in vitro. Co-transfection assays in Drosophila mbn-2 cells show that Gambif1 can activate transcription by interacting with the Drosophila Diptericin regulatory elements, but is not functionally equivalent to Dorsal in this assay. Gambif1 protein translocation to the nucleus and the appearance of kappaB-like DNA binding activity can serve as molecular markers of activation of the immune system and open up the possibility of studying the role of defence reactions in determining mosquito susceptibility/refractoriness to malaria infection.

Drosophila immunity: a comparative analysis of the Rel proteins dorsal and Dif in the induction of the genes encoding diptericin and cecropin

In Drosophila, bacterial challenge induces the rapid transcription of several genes encoding potent antibacterial peptides. The upstream sequences of the diptericin and cecropin Al genes, which have been investigated in detail, contain two, respectively one sequence element homologous to the binding site of the mammalian nuclear factor kappaB. These elements have been shown to be mandatory for immune-induced transcription of both genes. Functional studies have shown that these kappaB-related elements can be the target for the Drosophila Rel proteins dorsal and Dif. Here we present a comparative analysis of the transactivating capacities of these proteins on reporter genes fused to either the diptericin or the cecropin kappaB-related motifs. We conclude from our results: (i) the kappaB motifs of the diptericin and cecropin genes are not functionally equivalent; (ii) the dorsal and Dif proteins have distinct DNA-binding characteristics; (iii) dorsal and Dif can heterodimerize in vitro; (iv) mutants containing no copies of dorsal and a single copy of Dif retain their full capacity to express the diptericin and cecropin genes in response to challenge.

Drosophila immunity. A sequence homologous to mammalian interferon consensus response element enhances the activity of the diptericin promoter

Bacterial challenge of larvae or adults of Drosophila induces the rapid transcription of several genes encoding antibacterial peptides with a large spectrum of activity. One of these peptides, the 82-residue anti-gram negative diptericin, is encoded by a single intronless gene and we are investigating the control of expression of this gene. Previous studies using both transgenic experiments and footprint analysis have highlighted the role in the induction of this gene of a 30 nucleotide region which contains three partially overlapping motifs with sequence homology to mammalian NF-kappa B and NF-IL6 response elements and to the GAAANN sequence present in the interferon consensus response elements of some mammalian interferon-induced genes. We now show that the latter sequence binds in immune responsive tissues (fat body, blood cells) of Drosophila a approximately 45 kDa polypeptide which cross-reacts with a polyserum directed against mammalian interferon Regulatory Factor-I. Using a transfection assay of Drosophila tumorous blood cells, we show that the GAAANN sequence positively regulates the activity of the diptericin promoter. We propose that this motif cooperatively interacts with the other response elements in the regulation of the diptericin gene expression.

Coenzyme A glutathione disulfide. A potent vasoconstrictor derived from the adrenal gland

The adrenal gland is involved in the regulation of vascular tone by secretion of vasoactive agents such as catecholamines, neuropeptide Y, or endogenous ouabain. A further potent vasoconstrictor is isolated from bovine adrenal glands and is identified by chromatography, mass spectrometry, UV spectroscopy, and enzymatic cleavage as coenzyme A glutathione disulfide (CoASSG). CoASSG is found in chromaffin granules of adrenal glands and is released from adrenal medulla slices by carbachol. At a concentration of 10(-12) mol/L CoASSG increases renal vascular resistance. Intra-aortic injection of 5 x 10(-10) mol CoASSG increases blood pressure in the intact animal. Besides its vasopressor properties, this substance potentiates the effects of angiotensin II on vascular tone. It is concluded that CoASSG could play a role in blood pressure regulation not only by direct effects but also by modulation of the action of angiotensin II.

Butyrate modulates surfactant protein mRNA in fetal rat lung by altering mRNA transcription and stability

We examined the effects of Na butyrate, a known regulator of gene expression, on surfactant protein mRNA concentration, transcription, and degradation. Exposure of explants of 18-day fetal rat lung to Na butyrate resulted in a decrease in surfactant protein A (SP-A) mRNA concentration to 7% of control after 6 h and to 18% of control after 24 h. The reduction in SP-A mRNA concentration was associated with decreased mRNA transcription and stability at both these times. The effects on SP-B mRNA were similar to those on SP-A, but quantitatively less. In contrast, butyrate had a biphasic effect on SP-C mRNA concentration. There was an initial decrease to 30% of control at 6 h, followed by an increase to control levels by 24 h. Transcription of SP-C was increased at both these times, whereas degradation was enhanced at 6 h, but not at 24 h. The level of surfactant protein mRNA after butyrate treatment therefore depends on the balance between induced changes in transcription and degradation. Butyrate had no effect on gamma-actin mRNA concentration in this system. Circulating levels of butyric acid analogues are elevated in the mothers and fetuses in diabetic pregnancies. Some of these fetuses have delayed lung maturation and decreased amniotic fluid SP-A levels. We speculate that butyric acid analogues partially mediate the changes in pulmonary maturation induced by maternal diabetes.

Identification of Hox genes in newborn lung and effects of gestational age and retinoic acid on their expression

Hox genes are sequence-specific DNA transcription factors, which are important in embryonic development and are expressed in a number of fetal tissues, including the lung. Additionally, retinoic acid (RA) has been shown to modulate Hox gene expression in a number of cell types. The specific aims of this study were to 1) identify those Hox genes expressed in newborn mouse lung using reverse transcription-polymerase chain reaction (RT-PCR), 2) study the ontogeny of Hox gene expression in fetal mouse and rat lung by Northern analysis using cDNAs for mouse Hox genes, and 3) study the effects of RA on whole lung Hox mRNA levels in cultured fetal rat lung explants. Our data show that 16 different homeobox genes are expressed in newborn mouse lung. This includes seven Hox genes not previously identified in lung, as well as the divergent homeobox gene Hex. Steady-state mRNA levels of Hox A5 (Hox 1.3), B5 (Hox 2.1), B6 (Hox 2.2), and B8 (Hox 2.4) decrease with advancing gestational age in mouse lungs (E14 to adult). Similarly, Hox A5, B5, and B6 follow the same decreasing pattern of expression with advancing gestational age in rat lungs (E15 to adult). RA treatment of E17 rat lung explants in culture resulted in a significant dose- and time-dependent increase in Hox A5, B5, and B6 mRNA levels. The highest mRNA levels were seen in explants treated with 1 x 10(-5) M RA for 4-16 h. We conclude that there are many homeobox genes expressed in developing rodent lung and that their mRNA levels are affected by both gestational age and RA.

Combined hormonal therapy for the prevention of respiratory distress syndrome and its consequences

In performing this meta-analysis, we have attempted to use comparable data, but there are limitations to the information that is available at present. Some studies reported results for all patients entered, whereas others reported only optimally treated patients (Table 2). Many of the trials have not yet been published in final form and subjected to peer review. In addition, all the studies reported here were conducted before the widespread use of surfactant therapy. It is unclear whether the benefit of antenatal TRH and steroid therapy on end points such as death or BPD would persist if surfactant was also used. (Surfactant has, however, little impact on the percentage of survivors with BPD, perhaps because sicker infants survive with this treatment and go on to develop BPD.) Studies comparing antenatal TRH plus steroid plus postnatal surfactant to antenatal steroid plus postnatal surfactant are clearly required, and are in progress in a number of centers around the world. Because of these limitations, the routine use of antenatal TRH plus steroid cannot be currently recommended. However, the apparent benefits of this therapy in terms of RDS, death, and CLD that have been reported here do suggest that it might be used in selected situations. An example is threatened delivery of a very premature infant with an immature amniotic fluid pulmonary maturation profile. These infants are at risk for RDS and CLD, even if antenatal steroid and postnatal surfactant therapy is used.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma thyroid hormones and prolactin in premature infants and their mothers after prenatal treatment with thyrotropin-releasing hormone

We assayed TSH, triiodothyronine, free thyroxine, and prolactin (PRL) in plasma of women and infants participating in a trial of prenatal thyrotropin-releasing hormone (TRH) treatment for prevention of newborn lung disease. Women in labor at 26-34 wk of gestation received 400 micrograms of TRH i.v. every 8 h (one to four doses) plus 12 mg betamethasone (one or two doses); controls received saline plus betamethasone. Mean cord concentrations in control infants were TSH 9.7 mU/L, triiodothyronine 0.6 nmol/L (40.2 ng/dL), free thyroxine 14.4 pmol/L (1.13 ng/dL), and PRL 67.6 micrograms/L. TRH increased maternal plasma TSH by 100% at 2-4 h after treatment and decreased levels by 28-34% at 5-36 h. In cord blood of treated infants delivered at 2-6 h, TSH, triiodothyronine, and PRL were all increased about 2-fold versus control, and free thyroxine was increased 19%; the response was similar after one, two, three, or four doses of TRH. In treated infants delivered at 13-36 h, cord TSH and triiodothyronine levels were decreased 62 and 54%, respectively, and all thyroid hormones were lower after birth at 2 h of age versus control. We conclude that prenatal TRH administration increases thyroid hormones and PRL in preterm fetuses to levels similar to those normally occurring at term. Pituitary-thyroid function is transiently suppressed after treatment to a greater extent in fetus than mother, and infants born during the early phase of suppression do not have the normal postnatal surge in thyroid hormones.

Surfactant protein C: hormonal control of SP-C mRNA levels in vitro

We have studied hormonal regulation of the surfactant protein C (SP-C) in fetal 18-dah rat lung explants. SP-C mRNA was detected in Northern blots with a specific rat SP-C cDNA probe and quantified by densitometry. Treatment of the explants with dexamethasone resulted in a dose-dependent increase of the SP-C mRNA level. Transcriptional assays have shown that the regulation of SP-C mRNA by dexamethasone involves a transcriptional step. Administration of the cAMP analogues, 8-bromoadenosine 3',5'-cyclic monophosphate (8-BrcAMP) or dibutyryl adenosine 3',5'-cyclic monophosphate (DBcAMP), produced a dose-dependent increase of SP-C mRNA levels, with maximum stimulation observed at 200 microM. The thyroid hormone T3 had no effect on SP-C mRNA levels, whether administered alone or in combination with dexamethasone. Variation in the effects of the above hormones on three surfactant protein mRNAs, SP-A, SP-B and SP-C, indicates that the hormonal regulation of the surfactant proteins is a complex process and that each gene is, in part, differentially regulated.

Respiratory disease in very-low-birthweight infants after prenatal thyrotropin-releasing hormone and glucocorticoid. TRH Study Group

Although prenatal glucocorticoid treatment reduces neonatal respiratory morbidity, respiratory distress syndrome and chronic lung disease (CLD) develop in many very-low-birthweight infants despite therapy. To investigate the effect of additional prenatal treatment with thyrotropin-releasing hormone (TRH), we did a multicentre, blinded, randomised trial. 404 women with threatened preterm delivery at less than 32 weeks' gestation received betamethasone plus TRH (4 doses of 400 micrograms 8-hourly) or betamethasone plus placebo. 103 infants who were fully treated and of less than 1500 g birthweight were evaluated during the neonatal period. TRH treatment (55 infants) did not affect the total incidence of respiratory distress syndrome (47% vs 58% in controls) or of severe respiratory distress syndrome (13% vs 25% in controls, p = 0.11). CLD (defined as requirement for supplemental oxygen at 28 days after birth) developed in significantly fewer TRH-treated infants (18% vs 44% of controls, p less than 0.01). The unadjusted relative risk of CLD with TRH therapy was 0.40 (95% CI 0.26-0.80, p less than 0.05), and this was not materially changed after adjustment for potentially modifying variables. There were significantly fewer adverse outcomes, defined as death or continuing oxygen requirement, in the TRH group than in the steroid-alone group both at 28 days and when infants reached 36 weeks' postconceptional age. The incidence of other complications of prematurity was similar in the two groups. Prenatal TRH reduces the incidence of chronic lung disease among betamethasone-treated infants.

Comparison of the Maclura pomifera lectin-binding glycoprotein in late fetal and adult rat lung

The lectin, Maclura pomifera agglutinin (MPA), binds to alpha-galactose residues of glycoproteins on the apical surface of type II alveolar cells. It has recently been shown to bind to macrophages. We isolated the cell surface glycoprotein, which binds the MPA lectin, from fetal and adult rat whole lung to determine if changes in this glycoprotein occur during development from fetal to adult life. The glycoprotein was purified from whole lung cell membranes by lectin affinity chromatography that resulted in 10(5)-fold enrichment. The MPA binding glycoproteins from both fetal and adult lung had the same apparent molecular weight of 170 kD as determined by sodium dodecylsulfate-polyacrylamide gel electrophoresis. Amino acid analysis revealed similar composition of the fetal and adult proteins. Two-dimensional peptide maps of the 170 kD proteins isolated from fetal and adult lung were also similar. These data indicate that the glycoprotein that binds MPA to lung cell membranes does not change during this stage of development. Our method for the isolation of this glycoprotein can be used for the generation of antibodies or other molecular probes for further study of this protein.

Reduction of neonatal mortality after multiple doses of bovine surfactant in low birth weight neonates with respiratory distress syndrome

To determine if outcomes of low birth weight neonates with respiratory distress syndrome can be improved by the administration of multiple doses of bovine surfactant, we conducted two identical multicenter, controlled trials, and the results were combined for analysis. Seven hundred and ninety-eight neonates weighing 600 to 1750 g at birth who had developed respiratory distress syndrome within 6 hours of birth were assigned randomly to receive either 100 mg of phospholipid/kg of Survanta, a modified bovine surfactant (n = 402), or a sham dosing procedure (n = 396). Neonates whose respiratory distress persisted could be given up to three more doses, with all doses to be given in the first 48 hours after birth. Dosing was performed by investigators not involved in the clinical care of the neonates; nursery staff were kept blinded as to the treatment assignment. Fewer Survanta-treated neonates died of any cause (18.4% vs 27.3%, P = .002), died of respiratory distress syndrome (9.0% vs 20.3%, P less than .001), and either died or developed bronchopulmonary dysplasia due to respiratory distress syndrome (51.2% vs 64.6%, P less than .001). Neonates who received Survanta also had greater improvement in their oxygenation and ventilatory status from baseline to 72 hours than did control neonates. Survanta-treated neonates were at lowered risk for developing pulmonary interstitial emphysema (18.6% vs 39.3%, P less than .001) and other pulmonary air leaks (11.5% vs 25.9%, P less than .001). We conclude that multiple doses of Survanta given after diagnosis of respiratory distress syndrome reduce mortality and morbidity.