Hysteresis in phase volumes, compositions and interfacial roughness in model OPV-small-molecule/polymer thin-films.

Domain morphology and composition, and the structure of interfaces between domains are key factors in the performance and stability of organic photovoltaics (OPVs) fabricated from polymer/small-molecule blends. In this study, we investigate the evolution of composition, phase-volume and interfacial roughness in model polymer/small-molecule bilayers, in response to thermal annealing. Polystyrene/fullerene mixing is studied as a function of annealing temperature, using in situ neutron reflectivity, in thin-film bilayer samples comprising pure component or mixed layers. Remarkably, we discover that thermal annealing at temperatures around or above the reported glass transition temperatures, Tg, of the components can result in extensive mass-transfer between layers, that has the superficial appearance of equilibration, but leaves the layer compositions, thicknesses, and/or the interfacial composition profile in a non-equilibrium state. This is not merely a case of slow kinetics near Tg, as subsequent heating to higher temperatures, followed by cooling, reveals pronounced hysteresis in these systems. This has important implications for the measurement of equilibrium compositions in polymer/small-molecule mixtures for OPV applications, and for device stability during operation.

Liquid-liquid equilibrium in polymer-fullerene mixtures; an in situ neutron reflectivity study.

The composition profiles of a series of model polystyrene/fullerene bilayers are measured, before, during and after thermal annealing, using in situ neutron reflectometry. In combination with grazing-incidence X-ray diffraction measurements, these experiments, which quantify layer compositions as a function of molecular weight using changes in both scattering length density and layer thickness, extend and corroborate recent measurements on ex situ annealed samples and demonstrate that the composition profiles rapidly formed in these systems correspond to two co-existing liquid-liquid phases in thermodynamic equilibrium. The measurements also demonstrate a clear and systematic onset temperature for diffusion of the fullerenes into the PS layer that correlates with the known glass-transition temperatures of both the polymer (as a function of molecular weight) and the fullerene, revealing that the molecular mobility of the fullerenes in these systems is controlled by the intrinsic mobility of the fullerenes themselves and the ability of the polymer to plasticise the fullerenes at the interface. Over the temperature range investigated (up to 145 °C), measurements of equilibrated composition profiles as a function of temperature (during gradual cooling) reveal no significant changes in composition profile, other than those associated with the known thermal expansion/contraction of polystyrene thin-films.

Study protocol: older people in retirement villages. A survey and randomised trial of a multi-disciplinary invention designed to avoid adverse outcomes.

BACKGROUND: There is increasing interest among older people in moving into retirement villages (RVs), an attractive option for those seeking a supportive community as they age, while still maintaining independence. Currently in New Zealand there is limited knowledge of the medical, service supports, social status and needs of RV residents. The objective of this study is to explore RV facilities and services, the health and functional status of RV residents, prospectively study their healthcare trajectories and to implement a multidisciplinary team intervention to potentially decrease dependency and impact healthcare utilization. METHODS: All RVs located in two large district health boards in Auckland, New Zealand were eligible to participate. This three-year project comprised three phases: The survey phase provided a description of RVs, residents' characteristics and health and functional status. RV managers completed a survey of size, facilities and recreational and healthcare services provided in the village. Residents were surveyed to establish reasons for entry to the village and underwent a Gerontology Nurse Specialist (GNS) assessment providing details of demographics, social engagement, health and functional status. The cohort study phase examines residents' healthcare trajectories and adverse outcomes, over three years. The final phase is a randomised controlled trial of a multidisciplinary team intervention aimed to improve health outcomes for more vulnerable residents. Residents who triggered potential unmet health needs during the assessment in the survey phase were randomised to intervention or usual care groups. Multidisciplinary team meetings included the resident and support person, a geriatrician or gerontology nurse practitioner, GNS, pharmacist and General Practitioner. The primary outcome of the randomised controlled trial will be first acute hospitalization. Secondary outcomes include all acute hospitalizations, long-term care admissions, and all-cause mortality. DISCUSSION: This paper describes the study protocol of this complex study. The study aims to inform policies and practices around health care services for residents in retirement villages. The results of this trial are expected early 2020 with publication subsequently. TRIAL REGISTRATION: Australia and New Zealand Clinical Trials Registry: ACTRN12616000685415 . Registered 25.5.2016. Universal Trial Number (UTN): U111-1173-6083.

A time-driven, activity-based costing methodology for determining the costs of red blood cell transfusion in patients with beta thalassaemia major.

OBJECTIVES: To describe the methodology to estimate the total cost of administration of a single unit of red blood cells (RBC) in adults with beta thalassaemia major in an Australian specialist haemoglobinopathy centre. BACKGROUND: Beta thalassaemia major is a genetic disorder of haemoglobin associated with multiple end-organ complications and typically requiring lifelong RBC transfusion therapy. New therapeutic agents are becoming available based on advances in understanding of the disorder and its consequences. Assessment of the true total cost of transfusion, incorporating both product and activity costs, is required in order to evaluate the benefits and costs of these new therapies. METHODS: We describe the bottom-up, time-driven, activity-based costing methodology used to develop process maps to provide a step-by-step outline of the entire transfusion pathway. Detailed flowcharts for each process are described. Direct observations and timing of the process maps document all activities, resources, staff, equipment and consumables in detail. The analysis will include costs associated with performing these processes, including resources and consumables. Sensitivity analyses will be performed to determine the impact of different staffing levels, timings and probabilities associated with performing different tasks. RESULTS: Thirty-one process maps have been developed, with over 600 individual activities requiring multiple timings. These will be used for future detailed cost analyses. CONCLUSIONS: Detailed process maps using bottom-up, time-driven, activity-based costing for determining the cost of RBC transfusion in thalassaemia major have been developed. These could be adapted for wider use to understand and compare the costs and complexities of transfusion in other settings.

Predictors of death and new disability after critical illness: a multicentre prospective cohort study.

PURPOSE: This study aimed to determine the prevalence and predictors of death or new disability following critical illness. METHODS: Prospective, multicentre cohort study conducted in six metropolitan intensive care units (ICU). Participants were adults admitted to the ICU who received more than 24 h of mechanical ventilation. The primary outcome was death or new disability at 6 months, with new disability defined by a 10% increase in the WHODAS 2.0. RESULTS: Of 628 patients with the primary outcome available (median age of 62 [49-71] years, 379 [61.0%] had a medical admission and 370 (58.9%) died or developed new disability by 6 months. Independent predictors of death or new disability included age [OR 1.02 (1.01-1.03), P = 0.001], higher severity of illness (APACHE III) [OR 1.02 (1.01-1.03), P < 0.001] and admission diagnosis. Compared to patients with a surgical admission diagnosis, patients with a cardiac arrest [OR (95% CI) 4.06 (1.89-8.68), P < 0.001], sepsis [OR (95% CI) 2.43 (1.32-4.47), P = 0.004], or trauma [OR (95% CI) 6.24 (3.07-12.71), P < 0.001] diagnosis had higher odds of death or new disability, while patients with a lung transplant [OR (95% CI) 0.21 (0.07-0.58), P = 0.003] diagnosis had lower odds. A model including these three variables had good calibration (Brier score 0.20) and acceptable discriminative power with an area under the receiver operating characteristic curve of 0.76 (95% CI 0.72-0.80). CONCLUSION: Less than half of all patients mechanically ventilated for more than 24 h were alive and free of new disability at 6 months after admission to ICU. A model including age, illness severity and admission diagnosis has acceptable discriminative ability to predict death or new disability at 6 months.

Early-stage roughening of the polymer-polymer interface approaching the glass transition temperature by real-time neutron reflection.

The early-stage roughening of the interface between thin deuterated poly(methyl methacrylate) (d-PMMA) layers on thick polystyrene (PS) films was studied as a function of the temperature using real-time specular neutron reflectivity. By measuring the growth of the interface roughness as a precursor of the dewetting, the characteristic time constant of the early stages of the process was studied as a function of the temperature approaching the glass transition temperature (T(g)) of the two polymers from above and compared with the prediction of the growth of the interface by the spinodal process. Both solid and liquid regimes were probed, in which the viscosity of the thin film or the substrate dominates respectively. The characteristic growth time of the process also depends on the upper film thickness to a power of 5 or 6 in the solid or liquid regimes, respectively, as predicted by the theory of spinodal dewetting.

Detecting the Hidden Properties of Immunological Data and Predicting the Mortality Risks of Infectious Syndromes.

BACKGROUND: To extract more information, the properties of infectious disease data, including hidden relationships, could be considered. Here, blood leukocyte data were explored to elucidate whether hidden information, if uncovered, could forecast mortality. METHODS: Three sets of individuals (n = 132) were investigated, from whom blood leukocyte profiles and microbial tests were conducted (i) cross-sectional analyses performed at admission (before bacteriological tests were completed) from two groups of hospital patients, randomly selected at different time periods, who met septic criteria [confirmed infection and at least three systemic inflammatory response syndrome (SIRS) criteria] but lacked chronic conditions (study I, n = 36; and study II, n = 69); (ii) a similar group, tested over 3 days (n = 7); and (iii) non-infected, SIRS-negative individuals, tested once (n = 20). The data were analyzed by (i) a method that creates complex data combinations, which, based on graphic patterns, partitions the data into subsets and (ii) an approach that does not partition the data. Admission data from SIRS+/infection+ patients were related to 30-day, in-hospital mortality. RESULTS: The non-partitioning approach was not informative: in both study I and study II, the leukocyte data intervals of non-survivors and survivors overlapped. In contrast, the combinatorial method distinguished two subsets that, later, showed twofold (or larger) differences in mortality. While the two subsets did not differ in gender, age, microbial species, or antimicrobial resistance, they revealed different immune profiles. Non-infected, SIRS-negative individuals did not express the high-mortality profile. Longitudinal data from septic patients displayed the pattern associated with the highest mortality within the first 24 h post-admission. Suggesting inflammation coexisted with immunosuppression, one high-mortality sub-subset displayed high neutrophil/lymphocyte ratio values and low lymphocyte percents. A second high-mortality subset showed monocyte-mediated deficiencies. Numerous within- and between-subset comparisons revealed statistically significantly different immune profiles. CONCLUSION: While the analysis of non-partitioned data can result in information loss, complex (combinatorial) data structures can uncover hidden patterns, which guide data partitioning into subsets that differ in mortality rates and immune profiles. Such information can facilitate diagnostics, monitoring of disease dynamics, and evaluation of subset-specific, patient-specific therapies.

Geometry sensing through POR1 regulates Rac1 activity controlling early osteoblast differentiation in response to nanofiber diameter.

Bone grafting procedures in the United States rely heavily upon autografts and allografts, which are donor-dependent, cause donor site pain, and can transmit disease. Synthetic bone grafts can reduce these risks; however, synthetics lack the bone differentiating (osteoinductive) abilities of auto- and allografts. Achieving innate osteoinductive properties of synthetics through surface modifications is currently under investigation. This study focuses on nanofibers, with emphasis on how fiber diameter and the potential curvature sensor POR1 affect the activation of the signaling molecules Rac1 and Arf1, and leading to expression of alkaline phosphatase (ALP), an osteoinductive marker. Diameters of 0.1, 0.3, and 1.0 µm were compared against a flat control. The highest level of Rac1 activation was achieved on the smallest fibers (0.1 µm), a trend that was lost in POR1 knockdowns. This supports the hypothesis that on small nanofibers, POR1 favorably binds to highly curved cell membranes, which allows Rac1 to subsequently dissociate and activate. When the curvature is insufficient to bind POR1, POR1 binds to inactive Rac1 and competitively inhibits its activation. Arf1 activation followed an opposite trend, with the largest nanofibers exhibiting the highest activity. This trend reinforces the known interaction between Rac1 and Arf1 through the GIT-PIX complex, an Arf1 GAP and Rac1 GEF, respectively. Large, (1.0 µm), nanofibers demonstrated the highest ALP activity, indicating that ALP expression is inversely dependent on Rac1 activation. Knockdown of POR1 resulted in increased ALP activity across the substrates but without regard to the curvature sensing trend seen previously. Thus, POR1 senses curvature and increases Rac1 activity, which negatively regulates bone differentiation.

Immunocytochemical identification of basic fibroblast growth factor in the developing rat mammary gland: variations in location are dependent on glandular structure and differentiation.

We raised antiserum to human recombinant basic fibroblast growth factor (rbFGF) in rabbits. With this affinity-purified antiserum, other antisera to rbFGF, and commercial antiserum to bovine pituitary bFGF, we undertook immunocytochemical detection of bFGF in histological sections of rat mammary glands at different developmental stages. In non-growing ducts, anti-bFGF serum stains the basement membrane/myoepithelial cells, whereas in serial sections most of this stain is observed to be associated with anti-laminin-staining basement membranes rather than with anti-callus-keratin-staining myoepithelial cells. The weak staining of the myoepithelial cells is enhanced when NiCl2 is included in the detection system, but little staining for bFGF is observed in the epithelial cells. In growing neonatal ducts from 1-day-old rats, in growing terminal end buds (TEBs) and, to a lesser extent, in growing alveolar buds (ABs) in prepubescent (21-day) and pubescent (50-day) rats, both their inner and outer cells are stained moderately by anti-bFGF sera. In non-growing ducts from rats aged 6 days, in non-growing ABs of rats aged 60 days and more, and in alveoli from pregnant and lactating rats, only the basement membrane/myoepithelial cell area is stained by anti-bFGF sera; the epithelial cells are unstained. Staining of the myoepithelial cells is enhanced by mixtures of rbFGF and anti-bFGF sera in non-growing ducts, but there is little change in the staining of growing TEBs. All staining by anti-bFGF sera is abolished with heparin in the reactions. We suggest that the immunoreactive bFGF is present mainly bound to heparan sulfate glycosaminoglycans in the basement membrane of resting structures, but that immunoreactive bFGF becomes associated with proliferating cells, particularly those intermediate in characteristics between epithelial and myoepithelial cells in growing structures such as TEBs.

Rhinovirus infection associated with serious illness among pediatric patients.

Rhinovirus is an important cause of respiratory infection among all age groups, but it is primarily thought of as being responsible for upper respiratory tract infection. Rhinovirus was isolated from the respiratory tract of 48 pediatric patients who were hospitalized (40) or seen in a pediatric emergency room (8) during the period of July, 1985, through December, 1988. Twenty-eight (58%) of the patients presented during the spring and early summer. Forty-one (86%) of the 48 patients were less than 12 months of age. All except four of the patients had viral cultures performed because of respiratory symptoms. Bronchiolitis was the single most frequent clinical diagnosis and was noted in equal proportion among children less than 3 months and 3 to 12 months of age. Nine patients were assigned a diagnosis of suspected sepsis. Rhinovirus infection was a complication of underlying illness for 17 (44%) of the 40 hospitalized patients, and those patients tended to be older than the otherwise healthy hospitalized infants with rhinovirus. Twenty-six patients (54%) were treated with antibacterial agents, although only one patient was documented to have a concomitant bacterial infection (Chlamydia trachomatis). Overall rhinovirus isolation during the study period represented 0.7% of all specimens submitted for viral isolation compared with 8.2% for respiratory syncytial virus. Rhinovirus infection leads to hospitalization less frequently than does respiratory syncytial virus infection, but the severity of illness and clinical presentation in young infants are similar.

Pharyngitis associated with herpes simplex virus in college students.

During a 16-month period patients who presented to the Syracuse University Health Center with upper respiratory complaints had throat swabs obtained for viral, streptococcal and Mycoplasma pneumoniae cultures. Thirty-five of 613 patients (5.7%) had herpes simplex virus (HSV) isolated. All but 2 of the HSV isolates were found to be type 1 by immunofluorescent staining. Two HSV-positive patients also grew Group A Streptococcus, one grew M. pneumoniae and three had serum heterophile antibody tests that were positive. On physical examination 25 of the 35 HSV-positive patients had pharyngeal erythema and 14 had pharyngeal exudate. Twelve of these patients had vesicular lesions of the lips, throat or gums associated with their other symptoms. For 29 of the 35 HSV-positive students the primary diagnosis assigned was pharyngitis, for 2 the diagnosis was stomatitis and the remainder were assigned a primary diagnosis of upper respiratory infection, pneumonia, bronchitis or dental infection. Thirty-two of the 35 HSV-positive patients were treated with oral antibiotics and 7 were treated with oral or topical acyclovir. During the same 16-month period 89 (6.9%) of 1297 students presenting with sore throat were culture-positive for influenza A or B, 30 (2.3%) of 1283 were culture-positive for M. pneumoniae and 169 (2.8%) of the 6016 cultured for Group A Streptococcus were positive. Serum was tested for heterophile antibody in 2438 students, and 257 (10.5%) were positive. Herpes simplex virus is associated with pharyngeal symptoms in college students, and herpes simplex pharyngitis cannot easily be distinguished clinically from other causes of acute pharyngitis in this age group.

Efficient fabrication of precise electron cut-outs.

A time-saving method for creating accurate patient-personalized cerrobend cut-outs, utilized in electron beam therapy, is described--implemented by radiographic films taken during simulation. This technique is used frequently (but not exclusively) for the treatment of head and neck cancer, where isocentric lateral films taken for photon treatment also provide the information needed to define the posterior off-cord electron boost. The boost field is traced from the film and demagnified by xerox to the distance of the cone cut-out holder. A second simulation of the electron field is not necessary. Matching of the electron fields to the photon fields is accurate, consistent, and easy to define on the patient.

The critical care costs of the influenza A/H1N1 2009 pandemic in Australia and New Zealand.

The aim of this study was to determine the critical care and associated hospital costs for 2009 influenza A/H1N1 patients admitted to intensive care units (ICU) in Australia and New Zealand during the southern hemisphere winter All 762 patients admitted to ICUs in Australian and New Zealand between 1 June and 31 August 2009 with confirmed 2009 H1N1 influenza A were included. Costs were assigned based on ICU and hospital length-of-stay, using data from a single Australian ICU which estimated the daily cost of an ICU bed, along with published costs for a ward bed. Additional costs were assigned for allied health, overheads and extracorporeal membrane oxygenation services. The median (interquartile range) ICU and total hospital costs per patient were AU$35,942 ($10,269 to $82,152) and AU$51,294 ($22,849 to $110,340) respectively, while the mean (standard deviation) ICU and total hospital costs per patient were AU$63,298 ($78,722) and AU$85,395 ($147,457), respectively. A multivariate analysis found death was significantly associated with a reduction in the log of total costs, while the use of mechanical ventilation and ICU admission with viral pneumonitis/acute respiratory distress syndrome or secondary bacterial pneumonia were significantly associated with an increase in the log of total costs. The cost of 2009 H1N1 patients in ICU was significantly higher than the previously published costs for an average ICU admission, and the total cost of treating 2009 H1N1 patients in ICU admitted during winter 2009 was more than $65,000,000.

Measuring functional and quality of life outcomes following major head injury: common scales and checklists.

Traumatic brain injury (TBI) is a major public health issue, which results in significant mortality and long term disability. The profound impact of TBI is not only felt by the individuals who suffer the injury but also their care-givers and society as a whole. Clinicians and researchers require reliable and valid measures of long term outcome not only to truly quantify the burden of TBI and the scale of functional impairment in survivors, but also to allow early appropriate allocation of rehabilitation supports. In addition, clinical trials which aim to improve outcomes in this devastating condition require high quality measures to accurately assess the impact of the interventions being studied. In this article, we review the properties of an ideal measure of outcome in the TBI population. Then, we describe the key components and performance of the measurement tools most commonly used to quantify outcome in clinical studies in TBI. These measurement tools include: the Glasgow Outcome Scale (GOS) and extended Glasgow Outcome Scale (GOSe); Disability Rating Scale (DRS); Functional Independence Measure (FIM); Functional Assessment Measure (FAM); Functional Status Examination (FSE) and the TBI-specific and generic quality of life measures used in TBI patients (SF-36 and SF-12, WHOQOL-BREF, SIP, EQ-5D, EBIQ, and QOLIBRI).

Switching layer stability in a polymer bilayer by thickness variation.

We use optical and scanning force microscopy to explore the possibility of switching the stability of a bilayer of poly(methyl methacrylate) (PMMA) on polystyrene by simply changing the film thickness. We show that for thin PMMA layers on thicker polystyrene films the PMMA layer is unstable to thickness fluctuations. However, polystyrene layers are unstable when they are substantially thinner than the now stable PMMA film. Dewetting morphologies are cataloged as a function of the thickness of individual polymer layers by identifying which layer is unstable by which mechanism, be it spinodal dewetting or heterogeneous thermal nucleation. Our results are in good agreement with a linear stability analysis of the influence of long-range dispersion forces, but also indicate the influence of film preparation and small variations of material properties.

Temperament in velocardiofacial syndrome.

BACKGROUND: Velocardiofacial syndrome (VCFS) is a microdeletion syndrome caused by a 22q11.2 chromosomal deletion. METHODS: In this study, parents reported on their own temperament as well as the temperament of their child. Sixty-seven children with VCFS (mean age = 10.8, SD = 2.8; range 6-15), and age-, race- and gender-ratio matched samples of 47 community control participants (mean age = 10.4, SD = 2.6; range 6-15), and 18 sibling control participants (mean age = 12.1, SD = 1.9; range 9-15) took part in the current project. RESULTS: Children with VCFS have a temperament that may best be described as modestly difficult; while participants with VCFS were not more difficult across all temperamental domains, children with VCFS were rated by their parents as being: (1) less regular in their daily habits (e.g. eating at the same time each day, etc.); (2) less able to focus/sustain attention; (3) less cheerful/pleasant; (4) less likely to stay with an activity for a long time; and (5) less able to respond flexibly to changes in the environment. CONCLUSIONS: The best predictors of parent report of behavioural symptoms in children with VCFS were poor concordance between parent and child temperament across general activity level and mood domains.

Immunoblot analysis of anti-Ureaplasma urealyticum antibody in pregnant women and newborn infants.

The purpose of the present study was to determine the frequency in which antibody reactive to Ureaplasma urealyticum could be detected in a population of pregnant women and newborn infants. Serum samples from a prospective cohort of 80 healthy, U. urealyticum culture-positive and culture-negative pregnant women and a retrospective cohort of 522 infants born at between 25 and 42 weeks of gestation were studied by immunoblot analysis. Cultures of specimens from the lower genital tract were positive for U. urealyticum for 83% of the pregnant women, and serum immunoglobulin G (IgG) antibody which reacted to U. urealyticum was detectable in 93% of the pregnant women. Samples from five women (8%) had increases in the number of anti-U. urealyticum IgG bands over the course of the pregnancy. Samples from four of these five women had corresponding increases in the number of antibody bands present in IgA immunoblots. Six of the 522 samples from newborns or cord blood (1.1%) were positive for anti-U. urealyticum IgA; 5 of these 6 samples were also positive for IgM. The six anti-U. urealyticum IgA-positive infants were distributed as follows; 3 of 67 (4.5%) infants were delivered at 25 to 30 weeks of gestation, 3 of 176 (1.7%) infants were delivered at 31 to 34 weeks of gestation, and 0 of 279 infants were delivered at > or = 35 weeks of gestation. An antibody response to U. urealyticum can be detected in pregnant women and preterm infants and may serve as a marker of infection.

The timescale of spinodal dewetting at a polymer/polymer interface.

We investigate the dynamics of spinodal dewetting in liquid-liquid polymer systems. Dewetting of poly(methyl-methacrylate) (PMMA) thin films on polystyrene (PS) "substrates" is followed in situ using neutron reflectivity. By following the development of roughness at the PS/PMMA interface and the PMMA surface we extract characteristic growth times for the dewetting process. These characteristic growth times are measured as a function of the molecular weight of the two polymers. By also carrying out experiments in the regime where the dynamics are independent of the PS molecular weight, we are able to use dewetting to probe the scaling of the PMMA thin film viscosity with temperature and molecular weight. We find that this scaling reflects bulk behaviour. However, absolute values are low compared to bulk viscosities, which we suggest may be due in part to slippage at the polymer/polymer interface.

Immunolocalization of alpha-transforming growth factor in the developing rat mammary gland in vivo, rat mammary cells in vitro and in human breast diseases.

Immunoreactive alpha-transforming growth factor (alpha-TGF) was shown by immunocytochemistry to be present in the rat mammary gland at various stages of development, the staining being most intense in mature myoepithelial cells. Alpha-TGF was also detected in the secretions of the mammary glands of pregnant and lactating rats. alpha-TGF in the extracts of rat mammary glands at each stage of development, and in several rat mammary cell lines and in culture medium in which they had been grown, was shown by Western blotting to consist primarily of a protein of molecular weight 50 kDa. The amount of this protein was greater in the mammary gland of the lactating rat than in resting or involuting glands. alpha-TGF was also found in some, but not all, human breast carcinomas, and in benign hyperplastic breast diseases.

Development of hyperplasias, preneoplasias, and mammary tumors in MMTV-c-erbB-2 and MMTV-TGFalpha transgenic rats.

Human cDNAs corresponding to two epidermal growth factor-related products that are overexpressed in human breast cancers, that for c-erbB-2 (HER-2) and for transforming growth factor alpha (TGFalpha), have been cloned downstream of the mouse mammary tumor virus (MMTV) long terminal repeat promoter and injected into the pronucleus of fertilized oocytes of Sprague-Dawley rats to produce transgenic offspring. Expression of the transgenic mRNAs is not detectable in mammary tissue from virgin transgenic rats but is detected in mammary tissue from certain lines of mid-pregnant transgenic rats. When two such lines of either type of transgenic rat are subjected to repeated cycles of pregnancy and lactation, they produce, primarily in the mammary glands, extensive pathologies, whereas virgin transgenic rats produce no such abnormalities. Multiparous transgenic female offspring from c-erbB-2-expressing lines develop a variety of focal hyperplastic and benign lesions that resemble lesions commonly found in human breasts. These lesions include lobular and ductal hyperplasia, fibroadenoma, cystic expansions, and papillary adenomas. More malignant lesions, including ductal carcinoma in situ and carcinoma, also develop stochastically at low frequency. The mammary glands of transgenic females invariably fail to involute fully after lactation. Similar phenotypes are observed in female MMTV-TGFalpha transgenic rats. In addition, multiparous TGFalpha-expressing female transgenics frequently develop severe pregnancy-dependent lactating hyperplasias as well as residual lobules of hyperplastic secretory epithelium and genuine lactating adenomas after weaning. These transgenic rat models confirm the conclusions reached in transgenic mice that overexpression of the c-erbB-2 and TGFalpha genes predisposes the mammary gland to stochastic tumor development.