Harmonized Multisite MRI-Based Quantification of Human Liver Fat and Stiffness: A Pilot Study

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a leading cause of end-stage liver disease. NAFLD diagnosis and follow-up relies on a combination of clinical data, liver imaging, and/or liver biopsy. However, intersite imaging differences impede diagnostic consistency and reduce the repeatability of the multisite clinical trials necessary to develop effective treatments.

PURPOSE/HYPOTHESIS

The goal of this pilot study was to harmonize commercially available 3 T magnetic resonance imaging (MRI) measurements of liver fat and stiffness in human participants across academic sites and MRI vendors.

STUDY TYPE

Cohort.

SUBJECTS

Four community-dwelling adults with obesity.

FIELD STRENGTH/SEQUENCE

1.5 and 3 T, multiecho 3D imaging, PRESS, and GRE.

ASSESSMENT

Harmonized proton density fat fraction (PDFF) and magnetic resonance spectroscopy (MRS) protocols were used to quantify the FF of synthetic phantoms and human participants with obesity using standard acquisition parameters at four sites that had four different 3 T MRI instruments. In addition, a harmonized magnetic resonance elastography (MRE) protocol was used to quantify liver stiffness among participants at two different sites at 1.5 and 3 T field strengths. Data were sent to a single data coordinating site for postprocessing.

STATISTICAL TESTS

Linear regression in MATLAB, ICC analyses using SAS 9.4, one-sided 95% confidence intervals for the ICC.

RESULTS

PDFF and MRS FF measurements were highly repeatable among sites in both humans and phantoms. MRE measurements of liver stiffness in three individuals at two sites using one 1.5 T and one 3 T instrument showed repeatability that was high although lower than that of MRS and PDFF.

CONCLUSIONS

We demonstrated harmonization of PDFF, MRS, and MRE-based quantification of liver fat and stiffness through synthetic phantoms, traveling participants, and standardization of postprocessing analysis. Multisite MRI harmonization could contribute to multisite clinical trials assessing the efficacy of interventions and therapy for NAFLD.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY STAGE: 2.

Dietary Patterns and Prevalent NAFLD at Year 25 from the Coronary Artery Risk Development in Young Adults (CARDIA) Study

The prevalence of nonalcoholic fatty liver disease is rapidly rising. We aimed to investigate associations of diet quality and dietary patterns with nonalcoholic fatty liver disease (NAFLD) in Black and White adults. We included 1726 participants who attended the Year 20 Exam of the Coronary Artery Risk Development in Young Adults (CARDIA) study and had their liver attenuation (LA) measured using computed tomography at Year 25 (2010–2011). NAFLD was defined as an LA of ≤51 Hounsfield units after the exclusion of other causes of liver fat. The a priori diet-quality score (APDQS) was used to assess diet quality, and dietary patterns were derived from principal components analysis. Univariate and multivariable logistic regression models were used to evaluate the association between the APDQS, dietary patterns, and NAFLD, and were adjusted for Year 20 covariates. NAFLD prevalence at Year 25 was 23.6%. In a model adjusted for age, race, sex, education, alcohol use, physical activity, smoking, and center at Year 25, the APDQS was inversely associated (p = 0.004) and meat dietary pattern was positively associated (p < 0.0001) with NAFLD, while the fruit-vegetable dietary pattern was not significantly associated (p = 0.40). These associations remained significant when additionally adjusting for comorbidities (type 2 diabetes mellitus, dyslipidemia, hypertension), however, significant associations were diminished after additionally adjusting for body mass index (BMI). Overall, this study finds that the APDQS and meat dietary patterns are associated with prevalent NAFLD in mid-life. The associations appear to be partially mediated through higher BMI.

Gastric Xanthomatosis Secondary to Lipoprotein X in Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is a rare autoimmune disease characterized by intralobular bile duct destruction. Patients typically present with generalized symptoms including fatigue and pruritis, and less commonly, manifestations of lipid deposition including xanthomas and xanthelasmas. We report a case of a 31-year-old female with PBC-associated cirrhosis who had cutaneous xanthelasmas and diffuse gastric xanthomas secondary to hyperlipidemia and lipoprotein X that completely resolved following liver transplantation. While gastric xanthomas have been reported in patients with PBC previously, to our knowledge, this is the first case report of diffuse gastric xanthomas secondary to PBC reported to resolve following liver transplantation, suggesting that liver transplantation is curative for gastric xanthomatosis in patients with PBC-related cirrhosis.

Intact Fasting Insulin Identifies Nonalcoholic Fatty Liver Disease in Patients Without Diabetes

CONTEXT

Patients with nonalcoholic fatty liver disease (NAFLD) are characterized by insulin resistance and hyperinsulinism. However, insulin resistance measurements have not been shown to be good diagnostic tools to predict NAFLD in prior studies.

OBJECTIVE

We aimed to assess a newly validated method to measure intact molecules of insulin by mass spectrometry to predict NAFLD.

METHODS

Patients underwent a 2-hour oral glucose tolerance test (OGTT), a liver magnetic resonance spectroscopy (1H-MRS), and a percutaneous liver biopsy if they had a diagnosis of NAFLD. Mass spectrometry was used to measure intact molecules of insulin and C-peptide.

RESULTS

A total of 180 patients were recruited (67% male; 52 ± 11 years of age; body mass index [BMI] 33.2 ± 5.7 kg/m2; 46% with diabetes and 65% with NAFLD). Intact fasting insulin was higher in patients with NAFLD, irrespective of diabetes status. Patients with NAFLD without diabetes showed ~4-fold increase in insulin secretion during the OGTT compared with all other subgroups (P = 0.008). Fasting intact insulin measurements predicted NAFLD in patients without diabetes (area under the receiver operating characteristic curve [AUC] of 0.90 [0.84-0.96]). This was significantly better than measuring insulin by radioimmunoassay (AUC 0.80 [0.71-0.89]; P = 0.007). Intact fasting insulin was better than other clinical variables (eg, aspartate transaminase, triglycerides, high-density lipoprotein, glucose, HbA1c, and BMI) to predict NAFLD. When combined with alanine transaminase (ALT) (intact insulin × ALT), it detected NAFLD with AUC 0.94 (0.89-0.99) and positive and negative predictive values of 93% and 88%, respectively. This newly described approach was significantly better than previously validated noninvasive scores such as NAFLD-LFS (P = 0.009), HSI (P < 0.001), and TyG index (P = 0.039).

CONCLUSION

In patients without diabetes, accurate measurement of fasting intact insulin levels by mass spectrometry constitutes an easy and noninvasive strategy to predict presence of NAFLD.

Evidence-based clinical advice for nutrition and dietary weight loss strategies for the management of NAFLD and NASH

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide and affects approximately one third of adults in the United States. The disease is becoming a global epidemic as a result of the rising rates of obesity and metabolic disease. Emerging data suggest weight loss of ≥10% overall body weight is beneficial in resolving steatosis and reversing fibrosis. Prospective trials comparing various diets are limited by lack of sufficient power as well as pre- and post-treatment histopathology, and therefore no specific diet is recommended at this time. In this narrative review we examine the pathophysiology behind specific macronutrient components that can either promote or reverse NAFLD to help inform more specific dietary recommendations. Overall, the data supports reducing saturated fat, refined carbohydrates, and red and processed meats in the diet, and increasing the consumption of plant-based foods. Diets that incorporate these recommendations include plant-based diets such as the Dietary Approaches to Stop Hypertension, Mediterranean, vegetarian, and vegan diets.

Drug-Induced Liver Injury in the Setting of Chronic Liver Disease

Drug-induced liver injury (DILI) is an uncommon but significant cause of liver injury and need for liver transplant. DILI in the setting of chronic liver disease (CLD) is poorly understood. Clinical features of patients presenting with DILI in the setting of CLD are similar to those without CLD with the exception of a higher incidence of diabetes among those with CLD and DILI. Diagnosis of DILI in CLD is difficult because there are no objective biomarkers and current causality assessments have not been studied in this population. Differentiating DILI from exacerbation of underlying liver disease is even more challenging.

Hepatocellular carcinoma surveillance: An evidence-based approach

Hepatocellular carcinoma (HCC) makes up 75%-85% of all primary liver cancers and is the fourth most common cause of cancer related death worldwide. Chronic liver disease is the most significant risk factor for HCC with 80%-90% of new cases occurring in the background of cirrhosis. Studies have shown that early diagnosis of HCC through surveillance programs improve prognosis and availability of curative therapies. All patients with cirrhosis and high-risk hepatitis B patients are at risk for HCC and should undergo surveillance. The recommended surveillance modality is abdominal ultrasound (US) given that it is cost effective and noninvasive with good sensitivity. However, US is limited in obese patients and those with non-alcoholic fatty liver disease (NAFLD). With the current obesity epidemic and rise in the prevalence of NAFLD, abdominal computed tomography or magnetic resonance imaging may be indicated as the primary screening modality in these patients. The addition of alpha-fetoprotein to a surveillance regimen is thought to improve the sensitivity of HCC detection. Further investigation of serum biomarkers is needed. Semiannual screening is the suggested surveillance interval. Surveillance for HCC is underutilized and low adherence disproportionately affects certain demographics such as non-Caucasian race and low socioeconomic status.

Dual targeting of EGFR and ERBB2 pathways produces a synergistic effect on cancer cell proliferation and migration in vitro

Members of the epidermal growth factor receptor (EGFR/ERBB) gene family are frequently dysregulated in a range of human cancers, and therapeutics targeting these proteins are in clinical use. We hypothesized that similar pathways are involved in feline and canine tumours and that the same drugs may be of clinical use in veterinary patients. We investigated EGFR and ERBB2 targeting using a panel of feline and canine cell lines. EGFR and ERBB2 were targeted with siRNAs or tyrosine kinase inhibitors (TKIs) and their effect on cellular proliferation, colony formation and migration was investigated in vitro. Here we report that EGFR and ERBB2 combined siRNA targeting produced synergistic effects in feline and canine cell lines similar to that reported in human cell lines. We conclude that dual EGFR and ERBB2 targeting using TKIs should be further evaluated as a potential new therapeutic strategy in feline head and neck and mammary tumours and canine mammary tumours.

A comparative life-table analysis of Sipha flava (Hemiptera: Aphididae) on two biofuel hosts, Miscanthus x giganteus and Saccharum spp

Among the insects reported in biofuel crops, the yellow sugarcane aphid, Sipha flava (Forbes), is a potential pest of giant miscanthus, Miscanthus x giganteus Greef et Deu ex Hodkinson et Renvoize (M x g) and energy cane 'L79-1002', Saccharum spp. L. We studied the biology of S. flava on M x g and energy cane and estimated the development period, fecundity, longevity, intrinsic rate of increase, doubling time, reproductive value, and survivorship curves. To demonstrate the host suitability in a susceptible species, we studied the aphid life table on sorghum 'PL 18200,' Sorghum bicolor (L.) Moench. Life-table information was recorded under greenhouse conditions on the host plants. Our results suggested that both M x g and energy cane are suitable hosts for S. flava. We observed similar aphid development period on both hosts. Life-table estimates including longevity and fecundity suggested that M x g is a more suitable host for the aphid than energy cane. The intrinsic rate of increase for S. flava was lower on energy cane (0.231) than on M x g (0.258).

Relative feeding and development of armyworm on switchgrass and corn, and its potential effects on switchgrass grown for biomass

To help assess the potential for damage by armyworms [Mythimna (Pseudaletia) unipuncta (Haworth) (Lepidoptera: Noctuidae)] to switchgrass (Panicum virgatum L.) and surrounding crops, survival and development were evaluated for larvae reared on leaves of switchgrass, corn (Zea mays L.), and miscanthus (Miscanthus x giganteus Greef and Deuter ex Hodkinson and Renvoize). Additional tests assessed the relationship between leaf position and the concentration of saponins (plant compounds which can provide protection from insect herbivores) and examined the effect of defoliation on switchgrass dry mass. Survival to adulthood was similar when larvae were reared on field-grown leaves of switchgrass and corn. However, lower larval mass (10 d) and delayed development of M. unipuncta (to pupation, adult emergence) suggest switchgrass is an inferior host relative to corn. When fed field-grown miscanthus, no larvae survived 10 d. Few differences were noted between switchgrass and corn grown under controlled (laboratory) conditions, but M. unipuncta survival seemed to decline rapidly when larvae were fed the fourth and fifth leaves of switchgrass. Switchgrass leaf samples collected from different leaf positions and stages of tiller maturity showed up to 10-fold differences in the concentration of the saponin protodioscin, with the greatest concentrations in the fourth and fifth leaves. However, other saponins showed an opposite pattern, indicating the role of protodioscin on insect development should be tested in isolation (e.g., by addition of the purified compound to an artificial diet). Defoliation trials indicated that extremely high M. unipuncta populations may be necessary to cause any significant reduction in switchgrass biomass. Collectively, results suggest M. unipuncta may not present a significant risk to biomass production in switchgrass, but that the spring emergence of switchgrass provides an alternate host for M. unipuncta before colonizing annual food and feed crops.

First Report of Basal Stem Rot and Foliar Blight Caused by Pythium sylvaticum on Miscanthus sinensis in Illinois

Miscanthus sinensis Anderss., a perennial grass, is native to eastern Asia. It has been widely grown as an ornamental in temperate regions of the world, including the United States, and recently has become an important component of public and private sector bioenergy feedstock Miscanthus selection programs. In August 2008, stem rot and blight was observed on M. sinensis plants in two irregular patches, ~2 to 2.5 × 1 to 1.5 m each in a trial plot that was preceded by corn, at the University of Illinois Energy Farm near Urbana, IL. At the time of the observation, most plants were dead and the wilted tillers had black, soft rotted basal stems. A few plants were stunted and the crowns of the tillers had black-to-brown soft rot. Some tillers' leaves were dead and others had turned light brown. Sample tissue fragments were surface disinfested in 0.5% NaOCl and plated on 1% water agar (WA). After 3 days of incubation in the dark at 23°C, colonies were transferred to corn meal agar (CMA), potato dextrose agar (PDA), or 10% V8 juice agar and incubated at 23°C under continuous white light for up to 2 weeks. Morphological characteristics of the isolates correspond to those originally described for Pythium sylvaticum W.A. Campb. & J.W. Hendrix (1). The mycelia grew and covered the 10-cm-diameter plates within 5 days. On PDA, the culture was a creamy white mycelial mat of coenocytic hyphae. The isolates produced only globose, terminal or intercalary hyphal swellings ranging from 28 to 48 μm in diameter, but no oogonia were produced on any of the three growth media. No zoospores were produced when agar blocks bearing mycelium were flooded with distilled water or 1% soil water. Sequence analysis was performed with the internal transcribed spacer (ITS) region of the rDNA amplified with primer pair ITS1/ITS4 (3) and the mitochondrially encoded cytochrome c oxydase subunit II (cox II) gene using primers FM58/FM66 (2). The resulting 871-bp ITS nucleotide sequence (Accession No. HM991706) was identical among all three isolates analyzed and 99% identical (100% coverage) to ITS sequences of multiple isolates of P. sylvaticum in GenBank. Likewise, the 544-bp cox II sequence (Accession No. HQ454429) was 99% identical (97% coverage) to cox II sequences of multiple isolates of P. sylvaticum. Six pots of M. sinensis seedlings were inoculated by placing two CMA plugs of a 2-week-old culture of isolate F71 at the crown. The control pots were mock inoculated with sterile CMA plugs. The plants were incubated at ~90% relative humidity (RH) and 25°C day and 22°C night for 3 days, and thereafter left on the greenhouse bench at ~65% RH with alternating 9 h of darkness and 15 h of light. Three weeks after inoculation, two of the inoculated seedlings wilted, others were stunted with leaves wilting from the tip downwards and the stems rotting from the crown upward. A thick mat of mycelia was seen on the rotted basal stems. No symptoms were observed in the control. P. sylvaticum was reisolated from both the rotted basal stems and the wilted foliage. To our knowledge, this is the first report of P. sylvaticum on M. sinensis. Infestation of farm soils with P. sylvaticum could limit M. sinensis biomass production significantly by limiting seedling establishment. References: (1) W. A. Campbell and F. F. Hendrix. Mycologia 59:274, 1967. (2) F. M. Martin. Mycologia 92:711, 2000. (3) T. J. White et al. Page 38 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, 1990.

First Report of Pithomyces chartarum Causing a Leaf Blight of Miscanthus × giganteus in Kentucky

Miscanthus × giganteus is a warm-season perennial grass, native to eastern Asia. Brought into the United States as a landscape plant, it is currently being considered as a potential biomass fuel crop. In August 2009, a newly established and a 2-year-old M. × giganteus field research trial near Lexington, KY were found to have 100% incidence of severe leaf blight. Brown, mosaic-like, coalesced necrotic lesions covered leaf blades and sheaths on every stand, ultimately killing some leaves and tillers. The disease was more destructive in the newly established trial where 4- to 5-month-old M. × giganteus tillers were killed. No fruiting bodies were found immediately on diseased leaves. However, surface-disinfested diseased leaf tissue produced a sooty black mass of conidia after 1 week following incubation in a petri dish moisture chamber at 25°C in the dark. Single conidia isolations were made on half-strength potato dextrose agar (HSPDA) amended with 25 mg/liter of rifamycin and incubated at 25°C. Morphological characteristics of the fungus fit those originally described for Pithomyces chartarum (Berk. & Curt.) M.B. Ellis (2). Colonies were fast growing on HSPDA, at first hyaline, then shortly punctiform, grayish black, up to 1-mm diameter, and then became confluent, producing several dark brown multicellular conidia on small peg-like denticles on branched conidiophores. Every detached conidium had a small piece of the denticle attached to its base. The conidia were echinulate, broadly ellipsoidal, pyriform, 18 to 29 × 11 to 18 μm, with three transverse septa, and a longitudinal septum constricted at the transverse septa. The identity of the fungus was confirmed by sequence analysis of the internal transcribed spacers (ITS) region of the nuclear ribosomal DNA. The 615-bp cloned and sequenced amplicon (Accession No. GU195649) was 99% identical to sequences from multiple isolates of Leptosphaerulina chartarum (anamorph Pithomyces chartarum) in the GenBank. Five potted M. × giganteus plants (45 days old) were spray inoculated with an aqueous conidial suspension (2 × 10⁶ conidia/ml) and incubated in one tier of a two-tiered-growth chamber at 86 to 90% relative humidity. Initial incubation was in the dark at 26°C for 48 h, and thereafter at alternating 15 h of light (320 μmol) at 25°C and 9 h of darkness at 23°C. Control plants were sprayed with sterile water and incubated in the second tier of the same growth chamber. A week after inoculation, leaf blight developed on all inoculated plants, but not the controls. P. chartarum was reisolated from infected leaves 2 weeks after inoculation. To our knowledge, this is the first report of P. chartarum causing a disease on Miscanthus (3). The fungus is cosmopolitan, usually saprophytic, but can cause diseases on a wide range of plants as well as produce mycotoxins (3). It has been reported to cause a leaf spot of smooth bromegrass (Bromus inermis) in Nebraska (1) and a leaf blight of wheat (Triticum aestivum) in Hungary (4). The observed disease severity suggests P. chartarum could potentially limit M. × giganteus production as an ethanol feedstock. References: (1) C. Eken et al. Plant Dis. 90:108, 2006. (2) M. B. Ellis. Dematiaceous Hyphomycetes. Commonwealth Mycological Institute, Kew, Surrey, England, 1971. (3) D. F. Farr et al. Fungal Databases, Systematic Mycology and Microbiology Laboratory. Online publication. ARS, USDA, 2010. (4) B. Tóth et al. J. Plant Pathol. 89:405, 2007.

Development and feeding of fall armyworm on Miscanthus x giganteus and switchgrass

Observations of fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), larvae infesting plots of Miscanthus x giganteus Greef and Deuter ex Hodkinson and Renvoize prompted laboratory-based tests of survival, development, and feeding preferences on leaf tissue from M. x giganteus and switchgrass, Panicum virgatum L. Survival from hatch to pupation was >70 and 50% for fall armyworms reared on switchgrass and M. x giganteus, respectively, although survival of the S. frugiperda rice strain was significantly greater than the corn strain on both crops. Developmental times from hatch to pupation or adult emergence showed effects of crop and S. frugiperda host strain, but analysis of an interaction revealed developmental times for the rice strain were similar on both crops, whereas corn strain larvae showed delayed development on M. x giganteus relative to switchgrass. Analysis of larval (10 d) and pupal masses showed a similar pattern, with effects of crop and an interaction (at 10 d), but only the mass of corn strain larvae feeding on M. x giganteus was reduced relative to the other crop and strain combinations. In choice tests, neonates of both corn and rice strains showed a strong preference for feeding on young tissues rather than mature leaves of M. x giganteus or switchgrass, but they also clearly favored corn, Zea mays L., leaves over either of the perennial grasses. Results indicate both plants are potential hosts for S. frugiperda, but additional information is needed to understand under which scenarios and to what degree fall armyworms may damage perennial grasses grown for biofuel production.

Development and feeding of fall armyworm on Miscanthus x giganteus and switchgrass

Observations of fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), larvae infesting plots of Miscanthus x giganteus Greef and Deuter ex Hodkinson and Renvoize prompted laboratory-based tests of survival, development, and feeding preferences on leaf tissue from M. x giganteus and switchgrass, Panicum virgatum L. Survival from hatch to pupation was >70 and 50% for fall armyworms reared on switchgrass and M. x giganteus, respectively, although survival of the S. frugiperda rice strain was significantly greater than the corn strain on both crops. Developmental times from hatch to pupation or adult emergence showed effects of crop and S. frugiperda host strain, but analysis of an interaction revealed developmental times for the rice strain were similar on both crops, whereas corn strain larvae showed delayed development on M. x giganteus relative to switchgrass. Analysis of larval (10 d) and pupal masses showed a similar pattern, with effects of crop and an interaction (at 10 d), but only the mass of corn strain larvae feeding on M. x giganteus was reduced relative to the other crop and strain combinations. In choice tests, neonates of both corn and rice strains showed a strong preference for feeding on young tissues rather than mature leaves of M. x giganteus or switchgrass, but they also clearly favored corn, Zea mays L., leaves over either of the perennial grasses. Results indicate both plants are potential hosts for S. frugiperda, but additional information is needed to understand under which scenarios and to what degree fall armyworms may damage perennial grasses grown for biofuel production.

Population dynamics of a Western corn rootworm (Coleoptera: Chrysomelidae) variant in east central Illinois commercial maize and soybean fields

Three on-farm sites in Iroquois County, IL, each containing an adjacent 16.2-ha commercial production maize, Zea mays L., and soybean, Glycine max (L.) Merr., field, were monitored for western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), adults from June through September 1999-2001. Mean captures of D. v. virgifera adults as measured with Pherocon AM yellow sticky traps were significantly greater in maize than in soybean. Overall mean numbers of D. v. virgifera adults captured with vial traps were significantly greater in soybean than in maize. Emergence cage data revealed that after 50% emergence of D. v. virgifera adults occurred, peak captures of D. v. virgifera adults occurred in maize as measured with vial and Pherocon AM traps. After maize reached the R2 (blister stage, 10-14 d after silking) stage of development and 90% emergence of D. v. virgifera adults had occurred, peak captures of D. v. virgifera adults were observed in soybean by using vial and Pherocon AM traps. Also, after maize reached the R2 stage of development, numbers of females significantly increased in soybean and decreased in maize. Captures of female D. v. virgifera adults frequently exceeded published economic thresholds in soybean, regardless of trap type used. Estimated survival of variant D. v. virgifera (egg to adult) in these commercial rotated maize fields was 10.7 and 9.4% from 1999 to 2000 and from 2000 to 2001, respectively. This compares with nonvariant D. v. virgifera survival estimates in continuous maize production systems in Iowa of 6.7 and 11% from 1983 to 1984 and from 1984 to 1985, respectively.

Economic analysis of dynamic management strategies utilizing. Transgenic corn for control of western corn rootworm (Coleoptera: Chrysomelidae)

We studied management strategies for western corn rootworm, Diabrotica virgifera virgifera LeConte, using transgenic corn, Zea mays L., from both a biological and an economic perspective. In areas with and without populations adapted to a 2-yr rotation of corn and soybean (rotation-resistant), the standard management strategy was to plant 80% of a cornfield (rotated and continuous) to a transgenic cultivar each year. In each area, we also studied dynamic management strategies where the proportion of transgenic corn increased over time in a region. We also analyzed management strategies for a single field that is the first to adopt transgenic corn within a larger unmanaged region. In all areas, increasing the expression of the toxin in the plant increased economic returns. In areas without rotation-resistance, planting 80% transgenic corn in the continuous cornfield each year generated the greatest returns with a medium toxin dose or greater. In areas with alleles for rotation-resistance at low initial levels, a 2-yr rotation of nontransgenic corn and soybean, Glycine max (L.) Merr., may be the most economical strategy if resistance to crop rotation is recessive. If resistance to crop rotation is additive or dominant, planting transgenic corn in the rotated cornfield was the most effective strategy. In areas where rotation-resistance is already a severe problem, planting transgenic corn in the rotated cornfield each year was always the most economical strategy. In some cases the strategies that increased the proportion of transgenic corn in the region over time increased returns compared with the standard strategies. With these strategies the evolution of resistance to crop rotation occurred more rapidly but resistance to transgenic corn was delayed compared with the standard management strategy. In areas not managed by a regional norm, increasing the proportion of transgenic corn and increasing toxin dose in the managed field generally increased returns. In a sensitivity analysis, among the parameters investigated, only density-dependent survival affected the results.

Economics versus alleles: balancing integrated pest management and insect resistance management for rotation-resistant western corn rootworm (Coleoptera: Chrysomelidae)

Western corn rootworm, Diabrotica virgifera virgifera LeConte, has overcome crop rotation in several areas of the central United States. We expanded a simple model of adult behavior and population genetics to explain how rotation resistance may have developed and to study ways to manage the western corn rootworm in a landscape of corn, soybean, and winter wheat where evolution of resistance may occur. We modeled six alternative management strategies over a 15-yr time horizon, as well as a strategy involving a 2-yr rotation of corn and soybean in 85% of the landscape, to investigate their effectiveness from both a biological and economic perspective. Generally, resistance to crop rotation evolves in fewer than 15 yr, and the rate of evolution increases as the level of rotated landscape (selection pressure) increases. When resistance is recessive, all six alternative strategies were effective at preventing evolution of rotation resistance. The two most successful strategies were the use of transgenic rotated corn in a 2-yr rotation and a 3-yr rotation of corn, soybean, and wheat with unattractive wheat (for oviposition) preceding corn. Results were most sensitive to increases in the initial allele frequency and modifications of the density-dependent survival function. Economically, three alternative strategies were robust solutions to the problem, if technology fees were not too high. Repellant soybean, attractive rotated corn, and transgenic rotated corn, all in 2-yr rotations, were economically valuable approaches. However, even the currently common 2-yr rotation was economical when resistance was recessive and the actual costs of resistance would not be paid until far in the future.

Modeling the dynamics of adaptation to transgenic corn by western corn rootworm (Coleoptera: Chrysomelidae)

A simulation model of the population dynamics and genetics of the western corn rootworm, Diabrotica virgifera virgifera LeConte, was created for a landscape of corn, soybean, and other crops. Although the model was created to study a 2-locus problem for beetles having genes for resistance to both crop rotation and transgenic corn, during this first phase of the project, the model was simulated to evaluate only resistance management plans for transgenic corn. Allele expression in the rootworm and toxin dose in the corn plant were the two most important factors affecting resistance development. A dominant resistance allele allowed quick evolution of resistance to transgenic corn, whereas a recessive allele delayed resistance >99 yr. With high dosages of toxin and additive expression, the time required to reach 3% resistance allele frequency ranged from 13 to >99 yr. With additive expression, lower dosages permitted the resistant allele frequency to reach 3% in 2-9 yr with refuges occupying 5-30% of the land. The results were sensitive to delays in emergence by susceptible adults and configuration of the refuge (row strips versus blocks).

Predicting western corn rootworm (Coleoptera: Chrysomelidae) larval injury to rotated corn with Pherocon AM traps in soybeans

Crop rotation for portions of east central Illinois and northern Indiana no longer adequately protects corn (Zea mays L.) roots from western corn rootworm, Diabrotica virgifera virgifera LeConte. Seventeen growers in east central Illinois monitored western corn rootworm adults in soybean (Glycine max L.) fields with unbaited Pherocon AM traps during 1996 and 1997. In the following years (1997 and 1998), growers left untreated strips (no insecticide applied) when these fields were planted with corn. Damage to rotated corn by rootworms was more severe in untreated than in treated strips of rotated corn, ranging from minor root scarring to a full node of roots pruned. Densities of western corn rootworms in soybean fields from 1996 were significantly correlated with root injury to rotated corn the following season. Adult densities from 1997 were not significantly correlated with root injury in 1998, due to heavy precipitation throughout the spring of 1998 and extensive larval mortality. Twenty-eight additional growers volunteered in 1998 to monitor rootworm adults in soybean fields with Pherocon AM traps based on recommendations that resulted from our research efforts in 1996 and 1997. In 1999, these 28 fields were rotated to corn, and rootworm larval injury was measured in untreated strips. Based on 1996-1997 and 1998-1999 data, a regression analysis revealed that 27% of the variation in root injury to rotated corn could be explained by adult density in soybeans the previous season. We propose a sampling plan for soybean fields and a threshold for predicting western corn rootworm larval injury to rotated corn.

Temporal-spatial distribution of hepatocyte nuclear factor-3beta in developing human lung and other foregut derivatives

We assessed the temporal-spatial distribution of hepatocyte nuclear factor-3beta (HNF-3beta) in developing human lung and other foregut derivatives. Tissue from 31 fetuses (10-40 weeks) and 24 infants with hyaline membrane disease (HMD) or bronchopulmonary dysplasia (BPD) (2 days to 7 months) was studied. HNF-3beta was detected in nuclei of epithelial cells of trachea and of conducting and terminal airways at 10 weeks. Thereafter, epithelial nuclei were immunolabeled more widely in peripheral than proximal airways. HNF-3beta was confined to bronchiolo-alveolar portals and Type II cells in nonfetal lung. In infants with BPD, HNF-3beta was expressed abundantly in regenerating epithelial cells at the periphery of lung lobules. HNF-3beta was also detected in fetal esophagus, pancreas, duodenum, stomach, and gallbladder, suggesting that it is a marker for progenitor cells in foregut derivatives. The pattern of expression of HNF-3beta in the lung was similar to that of thyroid transcription factor-1 (TTF-1) at all ages. The temporal-spatial patterns of HNF-3beta and TTF-1 in the developing and regenerating lung are consistent with their proposed role in epithelial cell differentiation, regeneration, and surfactant protein gene expression. (J Histochem Cytochem 46:955-962, 1998)

Immunogold EM localization of neurochemicals in human pulmonary neuroendocrine cells

Antibodies against the pulmonary neuroendocrine cell peptides gastrin-releasing peptide (bombesin), calcitonin and calcitonin gene-related peptide (CGRP) have been labeled with colloidal gold spheres for immunocytochemical localization in human fetal and newborn lung tissue. In general, the presence and amount of immunolabeling increased with increasing gestational age, with only calcitonin appearing late in fetal life. The largest percentage of neuroepithelial body (NEB) cells labeled and the largest number of labeled dense core vesicles (DCV) were in infants with chronic lung disease (bronchopulmonary dysplasia). Serial ribbons allowed identification of more than one peptide in a single NEB cell. The use of two antibodies labeled with colloidal gold spheres of different sizes allowed the identification of two peptides in the same DCV. Quantification of relative amounts of labeled peptides was not possible, as the peptide labeling with the larger size gold sphere was consistently underestimated. Colocalization to the same DCV has been shown in humans for bombesin and calcitonin, calcitonin and CGRP, bombesin and CGRP and, by others for cholecystokinin (CCK) and serotonin. Colocalization of two or more peptides or an amine to a single DCV within the same cell implies simultaneous discharge by exocytosis. The action of the two (or more) substances might be in concert, perhaps with one acting in a paracrine fashion, and the second in an autocrine fashion. In this case, the second peptide or amine might have a regulatory function in the parent cell, influencing DCV storage or rate of release.

Immunogold EM localization of neurochemicals in human pulmonary neuroendocrine cells

Antibodies against the pulmonary neuroendocrine cell peptides gastrin-releasing peptide (bombesin), calcitonin and calcitonin gene-related peptide (CGRP) have been labeled with colloidal gold spheres for immunocytochemical localization in human fetal and newborn lung tissue. In general, the presence and amount of immunolabeling increased with increasing gestational age, with only calcitonin appearing late in fetal life. The largest percentage of neuroepithelial body (NEB) cells labeled and the largest number of labeled dense core vesicles (DCV) were in infants with chronic lung disease (bronchopulmonary dysplasia). Serial ribbons allowed identification of more than one peptide in a single NEB cell. The use of two antibodies labeled with colloidal gold spheres of different sizes allowed the identification of two peptides in the same DCV. Quantification of relative amounts of labeled peptides was not possible, as the peptide labeling with the larger size gold sphere was consistently underestimated. Colocalization to the same DCV has been shown in humans for bombesin and calcitonin, calcitonin and CGRP, bombesin and CGRP and, by others for cholecystokinin (CCK) and serotonin. Colocalization of two or more peptides or an amine to a single DCV within the same cell implies simultaneous discharge by exocytosis. The action of the two (or more) substances might be in concert, perhaps with one acting in a paracrine fashion, and the second in an autocrine fashion. In this case, the second peptide or amine might have a regulatory function in the parent cell, influencing DCV storage or rate of release.

Ontogeny of Clara cell-specific protein and its mRNA: their association with neuroepithelial bodies in human fetal lung and in bronchopulmonary dysplasia

Clara cell-specific 10-KD protein (CCSP) is an abundant product of nonciliated bronchiolar epithelial (Clara) cells in the lung. We have determined the temporal-spatial distribution of CCSP and its mRNA in developing human lung and in neonatal lung disease, using immunohistochemistry and in situ hybridization. CCSP immunoreactivity was found in nonciliated bronchiolar epithelial cells from 12 weeks of gestation onward. Tracheal and bronchial epithelia showed positive immunoreactivity at each gestational week after 15 weeks and 14 weeks, respectively. CCSP mRNA was seen in the bronchial and bronchiolar epithelia from 16 weeks onward and was detected in the trachea from 19 through 23 weeks of gestation. CCSP immunoreactivity and mRNA were present in nonciliated single cells of bronchial and bronchiolar epithelia in fetuses and in infants with and without lung disease. CCSP- and CCSP mRNA-containing epithelial cells also formed dusters around neuroepithelial bodies (NEBs), especially at airway branch points, suggesting that NEBs and Clara cells might interact during development and during pulmonary regeneration. Because of evidence of overlapping of some but not all cells expressing CCSP, SP-A, and pro-SP-B during lung development, a common cell lineage is proposed, with subsequent divergence of phenotypes.

Expression of thyroid transcription factor-1(TTF-1) in fetal and neonatal human lung

We assessed the immunohistochemical localization of thyroid transcription factor-1 (TTF-1) in the lungs of 24 human fetuses (11-23 weeks), three infants without pulmonary pathology (36-42 weeks), and 24 infants (2 days-6.5 months) with hyaline membrane disease (HMD) or bronchopulmonary dysplasia (BPD). TTF-1 was detected in fetal lung epithelial cell nuclei by 11 weeks' gestation. Budding tips of terminal airways had prominently labeled nuclei. By 17 weeks, labeling was present in scattered nonciliated columnar and cuboidal cells. Throughout gestation, TTF-1 nuclear staining was prominent in airways abutting pleural, peribronchial, or perivascular connective tissue, being less prominent in centers of lobules. By 23 weeks, many cells in cuboidal but not columnar cell-lined airways had labeled nuclei. At term, TTF-1 was detected primarily in Type II epithelial cells. In HMD with alveolar hemorrhage, edema, or airway collapse, little or no TTF-1 was present except in open terminal airways. In BDP lungs, TTF-1 was absent in areas of alveolar collapse or infection, being present in regenerating open airways. The temporal-spatial distribution of TTF-1, in general, follows patterns of distribution of surfactant protein-B in developing and pathological lungs, consistent with its role in the regulation of epithelial cell gene expression in the lung.

Respiratory syncytial virus infection enhances the response to laryngeal chemostimulation and inhibits arousal from sleep in young lambs

To evaluate the effect of respiratory syncytial virus (RSV) infection on the response to laryngeal chemostimulation (LCS) with water, five lambs were inoculated with human RSV and three lambs were given control media at an age of 3-5 days. During RSV infection, LCS resulted in increased inhibition of minute ventilation and delayed recovery of regular breathing. Sleep further increased the response, and arousal was less likely to occur in active sleep. Two of the five infected lambs needed resuscitation after LCS when arousal was absent. Histological studies showed bronchiolitis and pneumonitis. Laryngeal tastebud morphology was unchanged at 8 days after inoculation. However, infected lambs had disrupted tastebuds 4-6 weeks after infection. Failure to arouse and to terminate reflex apnea may play a role in the pathogenesis of the sudden infant death syndrome associated with respiratory tract infection.

Temporal-spatial distribution of SP-B and SP-C proteins and mRNAs in developing respiratory epithelium of human lung

We determined the temporal and spatial distribution of surfactant protein B (pro-SP-B) and C (pro-SP-C) mRNAs and proteins by immunohistochemistry and in situ hybridization in fetal, neonatal, and adult human lung. Pro-SP-B and SP-B mRNA were detected in bronchi and bronchioles by 15 weeks' gestation. After 25 weeks, pro-SP-B, active SP-B peptide, and SP-B mRNA were co-localized in bronchiolo-alveolar portal cells and in Type II epithelial cells. In adult lung, pro-SP-B and SP-B mRNA were detected primarily in non-ciliated bronchiolar epithelial cells and in Type II cells in the alveolus. Pro-SP-C and SP-C mRNA were detected in cells lining terminal airways from 15 weeks' gestation and thereafter. After 25 weeks, SP-C mRNA and precursor protein were detected in epithelial cells of the bronchiolo-alveolar portals and in Type II cells, where expression increased with advancing gestational age. Distinct cellular patterns of staining for pro-SP-B compared with SP-B active peptide support the concept that its proteolytic processing or cellular routing may be influenced by cell type and/or cell differentiation. SP-B and SP-C are expressed primarily in distal conducting and terminal airway epithelium of human fetal lung well in advance of surfactant lipid synthesis or physiologic requirements to produce pulmonary surfactant at the time of birth.

Developmental expression of SP-A and SP-A mRNA in the proximal and distal respiratory epithelium in the human fetus and newborn

We used immunolocalization and in situ hybridization to determine the distribution of SP-A and SP-A mRNA in lungs of human fetuses and normal newborn infants. Early in the second fetal trimester a few immunostained cells were observed in tracheal epithelium, often in mucosal folds near the origin of submucosal gland ducts. Non-mucous tracheal gland cells were immunostained for SP-A as they became differentiated. Expression of SP-A mRNA was similar to that of immunolocalization in the second trimester. Immunostained cells and SP-A mRNA also appeared about the same time in gestation in isolated cells of bronchial epithelium and glands. SP-A mRNA was seen in bronchiolar cells and pre-Type II cells lining terminal airways of fetuses at 19-20 weeks of gestation. Only in liveborn infants did cells of bronchioloalveolar portals and mature Type II cells contain SP-A mRNA or immunostain for SP-A. In postnatal infants, luminal material was also stained for SP-A. Although some alveolar macrophages contained immunoreactive material, SP-A mRNA was never detected. The abundance of SP-A in tracheal and bronchial glands and epithelium of conducting airways supports the importance of non-surfactant-associated functions for SP-A and may be related to a role in host defense.

Colocalization of peptide hormones in neuroendocrine cells of human fetal and newborn lungs: an electron microscopic study

This study investigated the colocalization of the peptide hormones bombesin or calcitonin with calcitonin gene related peptide (CGRP) in neuroendocrine cells (NE) in the lungs of human fetuses of varying gestational ages and in the lungs of newborn infants who died with acute or chronic lung disease in the first weeks or months after birth. Double immunolabeling of dense core granules for these peptides was also studied in this same patient population. On-grid double gold immunolabeling was carried out on 29 subjects using anti-bombesin and anti-CGRP and on 22 subjects using anti-calcitonin and anti-CGRP as primary antibodies, the secondary antibodies being labeled with different-size gold spheres. Colocalization of both bombesin and calcitonin with CGRP was demonstrated, not only in the same NE cell, but also on the same dense core granule. Colocalization was rarely found in normal fetuses, and most frequently found in newborn infants with acute lung disease, usually hyaline membrane disease (HMD), or with the development of chronic lung disease in the first weeks or months after birth. Double labeling of the same dense core granules might imply action of peptides in concert, or perhaps one peptide acting in a paracrine role (e.g., on bronchial or bronchiolar smooth muscle) and the second peptide acting in an autocrine fashion on the parent cell (e.g., in the regulation of granule production or release).

The ontogeny and distribution of surfactant protein B in human fetuses and newborns

The distribution of immunoreactive surfactant-associated protein B (IR-SP-B) was studied immunohistochemically in 120 subjects from 10 weeks of gestation to 7 postnatal months with a polyclonal antibody against human SP-B. Electron microscopy (EM) was done in 72 subjects to document the presence of Type II cells containing lamellar bodies. Fetuses of less than 18 weeks' gestation showed no immunostaining. Beginning at 18 weeks, non-mucous cells of tracheal glands immunostained in a few instances. Fetuses of 19 through 23 weeks showed progressive immunostaining of cells lining terminal airways. Infants 26-40 weeks who died with or without pulmonary pathology showed immunostaining of Type II cells and bronchioloalveolar (BA) portal cells of the respiratory bronchioles. In infants with hyaline membrane disease (HMD) who died less than 12 days after birth, occasional tracheal gland cells, BA portal cells, and mature and relining Type II cells immunostained. In bronchopulmonary dysplasia (BPD), BA portal cells, relining Type II cells, macrophages, and luminal material immunostained. Occasional tracheal and bronchial gland cells and Clara cells immunostained. The appearance of IR-SP-B at mid-gestation correlated with differentiation of Type II cells. There was good correlation of immunostaining with the presence of lamellar bodies on EM. Accelerated maturation of the lung was often associated with premature rupture of membranes (PROM).

Human surfactant protein-A contains blood group A antigenic determinants

A major blood group antigenic epitope was identified on human pulmonary surfactant protein A (SP-A). MAb and polyclonal antibodies generated against purified human SP-A aggregated blood group A human erythrocytes and immunostained epithelial cells in a variety of human tissues, consistent with the tissue distribution of major blood group antigens. SP-A MAb (MAb-8) agglutinated red cells and immunostained tissues from A or AB blood groups, but did not react with cells or tissues from O or B individuals. MAb-8 immunostaining of tissue from blood group A individuals was ablated by incubation with blood group A red cells. MAb and polyclonal antibodies directed against A blood group antigens reacted strongly with purified SP-A obtained from a blood group A individual with alveolar proteinosis. MAb and polyclonal antibodies specific for B blood group antigen failed to react with SP-A from this patient or from patients who were in blood group B. Reactivity of anti-blood group MAb was lost after treatment of SP-A with endoglycosidase-F, demonstrating its reactivity with an epitope dependent on the asparagine-linked oligosaccharide at asparagine 187. Reactivity of MAb-8 with SP-A persisted after endoglycosidase-F treatment, but was lost after digestion with collagenase as assessed by Western blot after SDS-PAGE. Reactivity of MAb to SP-A was sensitive to beta-elimination, supporting the presence of another blood group antigenic site distinct from the epitope dependent on the asparagine-linked carbohydrate. The finding that the SP-A molecule contains a major blood group epitope has implication for the clinical use of surfactant replacement preparations and diagnostic reagents based on this protein.

Lipocortin-1 immunoreactivity in the human pituitary gland

We evaluated the distribution of lipocortin-1 immunoreactivity in 118 immature or mature human hypophyses using the peroxidase-antiperoxidase (PAP) technique with a polyclonal rabbit antiserum against lipocortin-1. Serial sections were evaluated for five pituitary hormones and S-100 protein immunoreactivity to compare their distributions with that of lipocortin-1. Scattered or moderate numbers of cells exhibited lipocortin-1 immunoreactivity in the pars distalis of 89 subjects ranging in age from 27 weeks' gestation to 83 years. Seven immature and seven aged specimens exhibited no immunostaining, while 15 specimens from older individuals exhibited only rare immunostaining. Immunostaining did not appear to co-localize selectively with any specific pituitary hormone, although the distribution of immunoreactivity did overlap that of some corticotrophs and was seen in elongated processes of S-100-containing folliculostellate cells. Lipocortin-1 was also found in epithelial cells lining colloid cysts of the residual pars intermedia in 115 of 118 pituitaries ranging in age from 23 weeks' gestation to 83 years. In many intermediate lobe cysts, lipocortin-1 exhibited a pattern of immunoreactivity that partially overlapped the distribution of S-100 protein immunostaining, although the pattern was not identical. Pre-absorption of anti-lipocortin-1 antiserum with lipocortin-1-coupled Sepharose-4B immunoreactivity resulted in loss of immunoreactivity in both lobes. No lipocortin-1 immunoreactivity was seen in the neurohypophysis.

Factors related to practice of breast self-examination in rural women

The purpose of this study was to examine variables related to breast self-examination (BSE) in rural women. The sample of convenience consisted of 347 women who were members of selected county-extension homemaker clubs. Champion's Health Belief Model Scale was used to measure susceptibility, seriousness, benefits, barriers, health motivation, sociodemographics, and knowledge variables and frequency of BSE. Multiple regression analysis indicated that the Health Belief Model concepts accounted for 26% of the variance in BSE practice. Women who perceived more benefits of BSE in reducing the severity of breast cancer were more likely to report more frequent BSE. Women who perceived fewer barriers to performing BSE and those who scored high on health motivation were also more likely to report performing monthly BSE. Pearson product-moment correlation indicated a significant positive relationship between the variables of BSE knowledge and BSE practice (r = 0.1216; p = 0.023). The lambda statistics showed weak or no association between the demographic variables of age, race, marital status, religion, education, personal experience with breast disease, and friend's experience with breast disease and BSE practice. These findings suggest that perhaps educational programs emphasizing benefits of BSE may be implemented for women represented in this sample in an attempt to increase the number of women practicing BSE. Assessment of women's perceptions of potential barriers would allow nurses to plan appropriate strategies that could reduce the barriers. Finally, assessment of women's general health practices may identify women motivated toward good health. These women may be likely to complete monthly BSE if encouraged to do so.

Ontogeny of epidermal growth factor receptor and lipocortin-1 in fetal and neonatal human lungs

The ontogeny and distribution of the epidermal growth factor (EGF) receptor and lipocortin-1, a major cellular substrate of the EGF receptor, were evaluated in a developmental series of fetal and neonatal human lungs (8 to 41 weeks' gestation and stillborn to 16 days' postnatal age). The peroxidase anti-peroxidase technique with two polyclonal antibodies recognizing the EGF receptor and one polyclonal antibody recognizing lipocortin-1 were used for immunohistochemical localization. Extensive or scattered bronchiolar EGF receptor immunoreactivity appeared in the entire series of frozen lung specimens from 15 to 32 weeks' gestation. Bronchial glands exhibited EGF receptor immunostaining from 19 weeks onward, and immunoreactivity in bronchial epithelium was detected from 23 weeks onward. Most tracheas showed extensive lipocortin-1 immunoreactivity in the epithelium beginning at 10 weeks' gestation. Immunostaining was also seen in cells lining the ducts of submucosal glands after 15 weeks' gestation and in nonmucous acinar cells of tracheal glands after their appearance at 18 weeks' gestation. Bronchial epithelium exhibited lipocortin-1 immunoreactivity from 12 weeks' gestation onward. Bronchial gland necks became immunostained from 16 weeks' gestation onward, followed by acinar immunostaining as they subsequently developed. Bronchiolar epithelium was immunostained as early as 12 weeks, beginning with the largest airways, and by 24 weeks extending distally to the bronchioloalveolar portals. Lipocortin-1 immunostaining of larger conducting airway epithelium was primarily confined to ciliated cells. Neither EGF receptor nor lipocortin-1 immunoreactivity was detected in alveolar type I or type II cells, fibrocytes, chondrocytes, or smooth muscle cells at any gestational age. These developmental patterns suggest that the EGF receptor and lipocortin-1 may participate in normal growth factor-induced proliferation of the conducting airways and their glands in the human fetal lung and trachea.

Lung vascular permeability changes in lambs with hyaline membrane disease

To investigate the mechanism of pulmonary edema in hyaline membrane disease (HMD), lymph from the efferent duct of the mediastinal lymph node was collected in premature lambs before and after delivery by cesarean section. Mean lymph flow in 7 lambs with histologically verified HMD increased progressively over 4 h after delivery to 3 times the fetal value, while lymph flow in 7 lambs without HMD increased to 3.5 times at 1 h and decreased thereafter. At 4 h after birth, lung lymph flow was significantly higher in lambs with HMD than in lambs without HMD (0.70 +/- 0.15 (SEM) vs 0.43 +/- 0.07 ml.h-1.kg-1). Lymph/plasma concentration ratio for small endogenous protein fractions (effective molecular radius, 3.6 and 3.8 nm) was significantly higher in lambs with HMD than in lambs without HMD at 2-4 h. Postmortem extravascular lung water was significantly higher in lambs with HMD (6.1 +/- 0.5 vs 4.3 +/- 0.3 ml/g dry lung weight). It is concluded that lung water is high in lambs with HMD, which appears to be a result both of delayed absorption of fetal lung liquid and increased permeability of the pulmonary exchange vessels.

Ontogeny of epidermal growth factor receptor/kinase and of lipocortin-1 in the ovine lung

We have examined the ontogeny and distribution of the epidermal growth factor receptor/kinase (EGF receptor) and of lipocortin-1, a major cellular substrate of the EGF receptor, in a developmental series of 13 normal ovine fetal lungs (44-145 d of gestation) using the peroxidase anti-peroxidase technique with two extensively characterized polyclonal antibodies recognizing the EFG receptor and one polyclonal antibody recognizing lipocortin-1. Immunoreactive EGF receptor/kinase and lipocortin-1 were detected in conducting airway epithelium by the end of the first trimester of pregnancy before bronchial glands could be identified. This was followed at two-thirds of gestation by immunoreactivity in bronchial glands and large bronchioles adjacent to positive bronchi. By seven-eighths of gestation conducting airway epithelium no longer contained consistently detectable immunostaining for EGF receptor, although lipocortin-1 was identified until term in all levels of conducting airways. In contrast, neither EGF receptor nor lipocortin-1 immunoreactivity was detected in alveolar type I or type II epithelial cells, fibrocytes, chondrocytes, smooth muscle, or endothelial cells at any gestational age. These findings suggest that EGF receptor and lipocortin-1 may participate in early airway development.

Immunocytochemical localization of epidermal growth factor in the developing human respiratory system and in acute and chronic lung disease in the neonate

Cells staining for immunoreactive human epidermal growth factor were sought in the lungs and tracheas of human fetuses from 8 to 24 weeks of gestation. Lungs of liveborn infants from 25 to 40 weeks of gestation (stillborn to 7 months postnatal life), both with and without lung pathology, were also studied. In the early fetal trachea (12 to 15 weeks), many nonciliated cells immunostained for immunoreactive human epidermal growth factor in the lining epithelium. By 16 weeks of gestation this widespread staining was replaced by stained nonciliated single cells or small clusters of cells which were identifiable until 24 weeks. In the few tracheas which were available from liveborn infants who died without evidence of lung disease, stained cells were seldom identified in the lining epithelium after 24 weeks of gestation. In contrast, from 18 weeks until term, tracheal submucosal glands contained scattered cells which immunostained for immunoreactive human epidermal growth factor but which did not appear to be classical mucous cells. Beginning at 20 weeks of gestation, positively staining cells were found occasionally in bronchial lining epithelium, but more often in bronchial submucosal glands. Immunostained cells were never identified in bronchiolar epithelium in normal fetal or newborn lungs. In liveborn infants from 24 weeks onward who developed lung disease, many tracheas were severely damaged. In the presence of extensive denudation of the mucosa or the development of squamous metaplasia, immunostained cells were rarely seen in the lining epithelium. However, even under these conditions stained glandular cells could usually be identified. Stained cells were also present in the necks of those tracheal glands from which new epithelial lining cells appeared to be migrating onto denuded surfaces. Immunostained cells in the bronchial lining epithelium of infants with chronic lung disease were infrequent, just as they were in the fetus, but bronchial submucosal glands contained positively stained cells similar to those in tracheal glands. The appearance and distribution of immunostained cells were similar in the tracheal and bronchial submucosal glands in both normal subjects and those with all stages of lung disease. In contrast to the bronchioles of fetuses and infants without lung pathology, the bronchiolar epithelium of infants with chronic lung disease contained immunostained cells. Immunostained cells were found in areas of migrating dysplastic cells in relining conducting airways.(ABSTRACT TRUNCATED AT 400 WORDS)

Intestinal lipoprotein synthesis in control and hypercholesterolemic rats

Previous studies in our laboratory have shown that very-low-density lipoproteins (VLDL) synthesized by the intestine of the diet-induced hypercholesterolemic rat are enriched in cholesteryl esters and unesterified cholesterol compared with intestinal VLDL from control rats. In these studies, we isolated and characterized nascent intestinal Golgi intermediate-density lipoproteins (IDL, d 1.006-1.040 g/ml) and studied isotope incorporation into apoliproteins of Golgi VLDL from control and hypercholesterolemic rats. IDL were triacylglycerol-rich lipoproteins but contained more cholesteryl ester and protein than the corresponding Golgi VLDL fractions. IDL from hypercholesterolemic rats were enriched in cholesteryl esters to a greater extent than IDL from control rats. The apolipoprotein patterns of IDL fractions were the same as those of intestinal Golgi VLDL, consisting of apolipoproteins (apo) B-48, A-I and A-IV. Time-course isotope incorporation curves for apo A-I and A-IV in Golgi VLDL were similar, but they differed from curves for apo B-48. None of these curves was markedly altered in the hypercholesterolemic rat. We conclude that the major effect of increased dietary cholesterol on intestinal lipoprotein biosynthesis is to increase the percentage of cholesteryl esters in Golgi lipoproteins. Dietary cholesterol does not alter the apolipoprotein composition of Golgi lipoproteins, nor does it have a significant effect on the pattern of isotope incorporation into apolipoproteins of Golgi VLDL. The effect of cholesteryl ester enrichment on the subsequent metabolism of these particles in the circulation and the effect of these particles on hepatic lipoprotein production remain to be determined.

Effect of retinol on fetal lamb tracheal epithelium, with and without epidermal growth factor. A model for the effect of retinol on the healing lung of human premature infants

Twelve pairs of fetal lambs were used to test the hypothesis that the necrotizing tracheobronchitis followed by squamous metaplasia seen in premature infants who develop chronic bronchopulmonary dysplasia might be related to low retinol stores and might, therefore, be reversed by retinol supplementation. Epidermal growth factor (EGF) was used to model the growth factor stimulus initiated by chronic wounding of the airways, and retinol was used as a differentiator of proliferating cells stimulated by EGF. Saline-treated animals were used as controls, as were fetal lambs receiving retinol alone or EGF alone. The effects of EGF on tracheal and bronchial epithelium consisted of proliferation of basal and intermediate cells, necrosis and slough of lining ciliated and mucous-producing cells, followed by squamous metaplasia. In fetal lambs given retinol, plasma, liver and lung retinol levels rose and mucous producing cells were increased in number. In the presence of EGF plus retinol, differentiation of mucous-producing cells was accelerated. We believe that this fetal lamb model with low initial levels of retinol in plasma, liver and lung, treated with EGF may mimic human premature infants with chronic bronchopulmonary dysplasia, and that the addition of retinol in amounts sufficient to raise their tissue levels produces a more normal surface epithelium in conducting airways.

Calcitonin gene-related peptide in human fetal lung and in neonatal lung disease

The ontogeny of calcitonin gene-related peptide immunoreactivity (CGRP-IR) was evaluated immunohistochemically in 67 human fetal or newborn lungs previously analyzed for calcitonin immunoreactivity (CT-IR). CGRP-IR was present by 10 weeks of gestation in rare, solitary neuroendocrine (NE) cells of developing conducting airways in two of eight first-trimester lungs. During the second trimester, cells with CGRP-IR were found consistently (21/23 fetuses). However, the numbers of positively staining cells did not appear to increase in these fetuses or in third-trimester infants dying of non-pulmonary causes. The highest concentrations of CGRP-IR cells were seen in lungs of premature infants with advancing chronic lung disease associated with bronchopulmonary dysplasia (BPD). CGRP-IR was seen earlier in gestation and in greater numbers of NE cells than was calcitonin immunoreactivity (CT-IR) reported previously in these same fetal lungs (Lab Invest 52:52, 1985). Its presence paralleled that of CT-IR in postnatal chronic lung disease.

Beta-adrenergic receptor properties of a pulmonary alveolar type II cell preparation from the adult rat

The pulmonary alveolar type II cell synthesizes and secretes phosphatidylcholine (PC), a major component of surfactant, above basal level in response to beta-adrenergic stimulation. The investigation of the specific receptor which mediates these events was the topic of this study. Freshly isolated type II cells from adult rats were disrupted in a French pressure cell, and crude particulate fractions were recovered and used in assays for binding of the radioligand (-)-3-[125I]-iodocyanopindolol. The receptor had high affinity for beta-adrenergic agents, and specific binding to the receptor was saturable and reversible. The KD value obtained by kinetic means (19.6 pM) was in close agreement with that obtained by Scatchard (21.5 pM) and Hill (21.3 pM) analyses of steady-state binding data. The Scatchard correlation coefficients and Hill plot coefficients were close to 1, indicative of a single class of binding sites which displays no cooperativity. The specificity for catecholamine agonists and stereoselectivity observed were appropriate for a beta-adrenergic receptor. Use of selective drugs identified the presence of both beta 1- and beta 2-adrenergic receptor subtypes (1:3, respectively) on this cell type.

Ontogeny of neuroendocrine cells in human fetal lung. III. An electron microscopic immunohistochemical study

Immunocytochemistry at the transmission electron microscopic level utilizing colloidal gold spheres conjugated with secondary antisera was performed on lungs of 22 human fetuses and newborn infants of 13 to 38 weeks gestation and from birth to 5 1/2 months of postnatal life. Tissue was stained for the peptide hormones, immunoreactive (IR) bombesin, and IR calcitonin. In addition to unmatched neuroendocrine (NE) cells identified for these peptides, matched cells were identified in near-serial ribbons, each stained for an individual peptide. Based on morphology, five subtypes of NE cells were examined for these two peptides. We have confirmed the previously demonstrated developmental appearances of these peptides in human fetal lung. We also have found many cells containing both peptides in the lungs of live-born infants of 25 weeks gestation or more who survived long enough to develop chronic lung disease. The percentage of neurosecretory granules labeled for IR bombesin which overlapped with the percentage of granules labeled for IR calcitonin in cells of several dysplastic lung suggested that both peptides could be contained within a single granule. This was confirmed in NE cells of four such infants in preliminary studies utilizing double labeling immunocytochemistry at the electron microscopic level. At least two subpopulations of NE cells were not labeled for either peptide, suggesting that as yet-unidentified peptides and/or amines are contained in their granules. The possibility that large nonlabeled granules contain hormone precursors is also raised.

Immunocytochemical localization of human epidermal growth factor/urogastrone in several human tissues

Epidermal growth factor (EGF) stimulates the growth of many tissues and inhibits stimulated gastric acid secretion. Its primary tissue of origin in man is still unknown. We used polyclonal anti-human EGF sera in the peroxidase-antiperoxidase immunocytochemical staining technique to identify immunoreactive human EGF (ihEGF) in tissue sections from 29 subjects ranging from fetuses to 63 years in age. In addition to acinar cells in the submandibular salivary glands and cells of Brunner's duodenal glands, previously reported to contain ihEGF, we found ihEGF in most anterior pituitary glycopeptide hormone-secreting cells, in gastric and pyloric gland cells of the stomach, and in bone marrow cells that resembled mononuclear phagocytes in subjects of all ages. The eccrine sweat glands in the skin of adults also contained ihEGF. Cells containing ihEGF were found singly or in clusters in the trachea of the fetus only. No fetal pancreatic islet cells stained, but occasional cells in neonates and a majority of islet cells in older subjects contained ihEGF; there was no constant association with insulin, glucagon, or somatostatin. Only the lactating breast contained ihEGF. In adults, outer adrenomedullary cells contained ihEGF. Intense immunostaining was observed in the renal medulla, apparently limited to the extracellular area between the renal tubules, and increased with age; the cortex was devoid of ihEGF. No ihEGF was detected in posterior pituitary gland, thyroid gland, heart, lung, or liver at any age. An adult prostate contained ihEGF only in an area of local injury, and some primordial follicles from the ovary of a newborn appeared to contain ihEGF. Thus, many tissues appear to synthesize hEGF, which may exert exocrine, endocrine, or paracrine functions in different tissues and at different ages.

Ontogeny of neuroendocrine cells in human fetal lung. II. An immunohistochemical study

Immunocytochemistry using horseradish peroxidase-antiperoxidase technique was performed on the lungs of 60 human fetuses and newborn infants of 8 to 40 weeks' gestation and from birth to 7 months' postnatal life. Tissue was stained for the peptide hormones, immunoreactive (IR) bombesin, IR calcitonin and IR Leu-enkephalin, as well as for IR serotonin. IR bombesin appeared in neuroendocrine cells and neuroepithelial bodies in the developing conducting airways of fetuses by 10 weeks' gestation and increased in number primarily in bronchioles as gestation progressed. They were most numerous in live-born infants with chronic respirator lung disease. In contrast, IR calcitonin-staining cells did not appear until late in the second trimester. They were present in small numbers from 20 weeks onward but were also most numerous in infants with chronic respirator lung disease. IR serotonin-staining cells were readily found in lungs of fetuses in the first trimester. By the second trimester many solitary neuroendocrine cells and neuroepithelial bodies staining for IR serotonin were present in developing terminal airways and a lesser number appeared in bronchioles and intrapulmonary bronchi. In premature infants, IR serotonin-staining cells were scarce in the presence of acute hyaline membrane disease but were numerous in lungs of infants with regenerating conducting airways associated with chronic respirator lung disease. IR Leu-enkephalin-staining cells were found only in one infant who survived 7 postnatal months of respirator care following neonatal hyaline membrane disease.

Ontogeny of neuroendocrine cells in human fetal lung. I. An electron microscopic study

An electron microscopic study of human fetal lung was undertaken to describe the ontogeny of neuroendocrine (NE) cells and neuroepithelial bodies (NEBs) and to determine their relationships to the developing nervous system. Lungs of 34 fetuses and 22 newborns were examined. Putative NE cells appeared prior to 8 weeks of gestation but, by 10 weeks, differentiated into NE cells and NEBs. Between 13 and 24 weeks the number of NE cells and NEBs increased, and subpopulations of NE cells were identified: a small population of cells that reached from basement membrane to lumen and NE cells associated with an electron-dense epithelial cell. Material past 24 weeks of gestation was obtained from live-born infants who died at various postnatal ages. Much of this material represented acute pulmonary damage in which NE cells were difficult to identify. As chronic lung disease developed, NE cells, singly and in groups, were easily identified in regenerating conducting airways. Growing axons associated with both NE cells and NEBs appeared as early as 10 weeks of gestation. Rare cholinergic, adrenergic, and nonadrenergic-noncholinergic terminals were identified in contact with NE cells and deep within NEBs. Afferent axon terminals were not identified with certainty. The data presented demonstrate innervation to at least some NE cells and NEBs throughout fetal life. It has been proposed that NE cells and NEBs are intrapulmonary neuroreceptors with paracrine secretory function. The present study suggests more complicated mechanisms integrated with the autonomic nervous system, inducing reflex activity at the level of the central nervous system. A tropic role for NE cells in the developing and regenerating lung is proposed.

Intestinal lipoprotein synthesis. Comparison of nascent Golgi lipoproteins from chow-fed and hypercholesterolemic rats

Hypercholesterolemia, induced by a cholesterol-enriched diet, is associated with distinctive modifications in the serum lipoproteins of a variety of species. Present in the serum of these animals are several classes of lipoproteins enriched in cholesteryl esters and apolipoprotein E. To investigate the role of intestinal lipoprotein synthesis in diet-induced hypercholesterolemia, we characterized nascent lipoproteins retrieved from Golgi apparatus-rich fractions of intestinal epithelial cells from chow-fed control and hypercholesterolemic rats. To eliminate chylomicrons from the preparations, rats were fasted overnight prior to the experiments. Golgi very low density lipoproteins (d less than 1.006 g/ml) from control rats were triglyceride-rich lipoproteins that migrated slightly slower than pre-beta migrating serum very low density lipoproteins. These particles contained apoproteins B-240, A-IV, and A-I. Golgi very low density lipoproteins from hypercholesterolemic rats were likewise triglyceride-rich lipoproteins migrating electrophoretically like control Golgi very low density lipoproteins and they contained apoproteins B-240, A-IV, and A-I. However, these latter particles contained less triglyceride and more cholesterol compared to control Golgi very low density lipoproteins. In addition, by radioisotope incorporation studies, Golgi very low density lipoproteins from hypercholesterolemic rats contained relatively more apoprotein A-IV (21.6 vs. 11.0%) and less apoprotein B-240 (17.0 vs. 27.0%) than found in control Golgi very low density lipoproteins. Approximately 60% of the total apoprotein radioactivity was found in apoprotein A-I in both preparations. We conclude that intestinal lipoprotein synthesis is modified by diet-induced hypercholesterolemia. The significance of these modifications with respect to the marked hypercholesterolemia observed in these animals remains to be determined.

Pulmonary hemodynamic and ultrastructural changes associated with Group B streptococcal toxemia in adult sheep and newborn lambs

A toxin isolated from Group B beta-hemolytic streptococci, Type III was infused into adult sheep and newborn lambs. A two-phased reaction was observed. There was an initial phase of pulmonary hypertension and high flow of protein-poor lymph. This was followed by a second phase when pressures returned to baseline but lymph flow remained twice the baseline values and protein concentration in lymph increased. During the second phase there was a significant increase in lymph protein clearance, suggestive of increased microvascular permeability to protein. The absolute granulocyte count decreased to 10% of baseline values by 60 min after the infusion, and was followed by a variable return to baseline. The sheep with the largest changes in protein clearance were those who had the slowest return to baseline values. Pathologic examination of lung tissue revealed there was capillary dilation, interstitial edema, and large numbers of granulocytes in the lungs. The basement membranes of both capillaries and arterioles showed disruption and widening, along with fragmentation of the internal elastic membrane. This study provides morphologic and physiologic evidence of increased pulmonary vascular permeability after injection of streptococcal toxin associated with granulocyte trapping in the lung. We postulate that granulocytes may be involved as mediators of the pulmonary vascular injury.

The effect of pangamic acid on maximal treadmill performance

The effect of pangamic acid (calcium gluconate and N, N-Dimethylglycine) ingestion was examined during short-term maximal treadmill performance on 16 male track athletes. The study was conducted as a double-blind experiment with an experimental group (E) whose members each ingested six 50-mg pangamic acid tablets per day and a control group (C) whose members each ingested six placebo tablets per day for three weeks. The placebo tablets were identical to the pangamic acid tablets in appearance. Subjects were tested by using the Bruce treadmill protocol before and after treatment. The following parameters were examined: maximal heart rate (HR), treadmill time (TM), recovery HR at minutes 1 and 3, and pre-test and post-test blood glucose and lactate levels. Pre-treatment data were 183 bpm (E) and 194 bpm (C) for maximal HR, 16.99 min (E) and 16.49 min (C) for TM, 132.13 mg% (E) and 133.38 mg% (C) for post-test glucose, and 64.63 mg% (E) and 76.13 mg% (C) for post-test lactate. Post-treatment data were 181 bpm (E) and 194 bpm (C) for maximal HR, 17.21 min (E) and 16.83 min (C) for TM, 138.88 mg% (E) and 139.13 mg% (C) for post-test glucose, and 70.88 mg% (E) and 66.58 mg% (C) for post-test lactate. Multivariate analysis of variance (MANOVA) revealed no significant differences (P greater than 0.05) between groups after treatment. It was concluded that ingestion of pangamic acid does not produce significant changes in short-term maximal treadmill performance.