Habitat and climate influence hybridization among three genetically distinct Canada jay (Perisoreus canadensis) morphotypes in an avian hybrid zone complex

Examining the frequency and distribution of hybrids across contact zones provide insights into the factors mediating hybridization. In this study, we examined the effect of habitat and climate on hybridization patterns for three phenotypically, genetically, and ecologically distinct groups of the Canada jay (Perisoreus canadensis) in a secondary contact zone in western North America. Additionally, we tested whether the frequency of hybridization involving the three groups (referred to as Boreal, Pacific and Rocky Mountain morphotypes) is similar across the hybrid zones or whether some pairs have hybridized more frequently than others. We reanalyzed microsatellite, mtDNA and plumage data, and new microsatellite and plumage data for 526 individuals to identify putative genetic and phenotypic hybrids. The genetically and phenotypically distinct groups are associated with different habitats and occupy distinct climate niches across the contact zone. Most putative genetic hybrids (86%) had Rocky Mountain ancestry. Hybrids were observed most commonly in intermediate climate niches and in habitats where Engelmann spruce (Picea engelmannii) overlaps broadly with boreal and subalpine tree species. Our finding that hybrids occupy intermediate climate niches relative to parental morphotypes matches patterns for other plant and animal species found in this region. This study demonstrates how habitat and climate influence hybridization patterns in areas of secondary contact and adds to the growing body of research on tri-species hybrid zones.

A test of the predator avoidance hypothesis to explain delayed onset of communal breeding

A neglected question in the study of communal breeding concerns why alloparental behaviour begins at variously late stages in the breeding cycle. In group-living corvids, the delay tends to be longer in species that are small and (or) typically have only a small nonbreeder complement. This pattern has been attributed to the relatively poor defensive capabilities of such species and their consequently greater need to minimize predator-attracting traffic to the nest or fledglings. We tested this predator avoidance hypothesis with the Canada Jay (Perisoreus canadensis (Linnaeus, 1766)), a species in which the feeding of young by any nonbreeders in the family group is delayed until the fledgling period. We reasoned that, on Anticosti Island, Quebec (Canada), in the absence of squirrels and other nest predators, nonbreeders might be permitted to feed nestlings as well as fledglings, and that breeders might feed nestlings more frequently (with smaller food loads) than on the mainland. We found no evidence for either prediction and thus no support for the predator avoidance hypothesis but suggest that Anticosti Canada Jays may have had insufficient time to evolve behaviour more appropriate for their predator-free environment. Secondarily, we confirmed that in all observed instances, the nonbreeders were offspring of the breeding pair from previous years and that they therefore failed to provision nestlings in spite of an apparent genetic interest to do so.

Isotopic spiking and food dye experiments provide evidence that nestling Canada Jays (Perisoreus canadensis) receive cached food from their parents

While many animals rely on stored food to survive periods of no or few resources, some of these species may also use cached food to feed young. The Canada Jay (Perisoreus canadensis (Linnaeus, 1766)) is a territorial, food-caching resident of North American boreal forests. Canada Jays have high winter survival when fresh food is rarely available and achieve high fledging rates before the return and breeding of most sympatric migratory passerines. Stored food must account for the Canada Jay’s winter survival, but it is less certain that stores are also used to feed nestlings. We conducted two experiments seeking evidence of such use, one using food marked with dye and a second using 15N-enriched glycine. Breeding pairs were supplemented with marked food in the pre-incubation period, followed by our attempts to find the marker in nestling feces (dye experiment) or feathers (15N-enrichment experiment). Both experiments provided evidence that at least some nestlings had ingested the marker, although the importance of this behaviour within the population remains unknown. Our study demonstrates how food markers can be used to infer feeding behaviour that has not been directly recorded in the wild, even after over 50 years of close observation.

Cord blood Streptococcus pneumoniae-specific cellular immune responses predict early pneumococcal carriage in high-risk infants in Papua New Guinea

In areas where Streptococcus pneumoniae is highly endemic, infants experience very early pneumococcal colonization of the upper respiratory tract, with carriage often persisting into adulthood. We aimed to explore whether newborns in high‐risk areas have pre‐existing pneumococcal‐specific cellular immune responses that may affect early pneumococcal acquisition. Cord blood mononuclear cells (CBMC) of 84 Papua New Guinean (PNG; high endemic) and 33 Australian (AUS; low endemic) newborns were stimulated in vitro with detoxified pneumolysin (dPly) or pneumococcal surface protein A (PspA; families 1 and 2) and compared for cytokine responses. Within the PNG cohort, associations between CBMC dPly and PspA‐induced responses and pneumococcal colonization within the first month of life were studied. Significantly higher PspA‐specific interferon (IFN)‐γ, tumour necrosis factor (TNF)‐α, interleukin (IL)‐5, IL‐6, IL‐10 and IL‐13 responses, and lower dPly‐IL‐6 responses were produced in CBMC cultures of PNG compared to AUS newborns. Higher CBMC PspA‐IL‐5 and PspA‐IL‐13 responses correlated with a higher proportion of cord CD4 T cells, and higher dPly‐IL‐6 responses with a higher frequency of cord antigen‐presenting cells. In the PNG cohort, higher PspA‐specific IL‐5 and IL‐6 CBMC responses were associated independently and significantly with increased risk of earlier pneumococcal colonization, while a significant protective effect was found for higher PspA‐IL‐10 CBMC responses. Pneumococcus‐specific cellular immune responses differ between children born in pneumococcal high versus low endemic settings, which may contribute to the higher risk of infants in high endemic settings for early pneumococcal colonization, and hence disease.

Nonlinear laser pulse response in a crystalline lens

The propagation characteristics of a spatial Gaussian laser pulse have been studied inside a gradient-index structured crystalline lens with constant-density plasma generated by the laser-tissue interaction. The propagation of the laser pulse is affected by the nonlinearities introduced by the generated plasma inside the crystalline lens. Owing to the movement of plasma species from a higher- to a lower-temperature region, an increase in the refractive index occurs that causes the focusing of the laser pulse. In this study, extended paraxial approximation has been applied to take into account the evolution of the radial profile of the Gaussian laser pulse. To examine the propagation characteristics, variation of the beam width parameter has been observed as a function of the laser power and initial beam radius. The cavitation bubble formation, which plays an important role in the restoration of the elasticity of the crystalline lens, has been investigated.

Effect of multiphoton ionization on performance of crystalline lens

This Letter presents a model for propagation of a laser pulse in a human crystalline lens. The model contains a transverse beam diffraction effect, laser-induced optical breakdown for the creation of plasma via a multiphoton ionization process, and the gradient index (GRIN) structure. Plasma introduces the nonlinearity in the crystalline lens which affects the propagation of the beam. The multiphoton ionization process generates plasma that changes the refractive index and hence leads to the defocusing of the laser beam. The Letter also points out the relevance of the present investigation to cavitation bubble formation for restoring the elasticity of the eyes.

Generation of 400 μW at 17.5 μm using a two-color Yb fiber chirped pulse amplifier

We have demonstrated the generation of 400 μW of power at ~18 μm by difference-frequency mixing the 1038 and 1105 nm from a two-color, chirped pulse amplification Yb fiber system. A two-color seed is selected from a continuum source and amplified to 300 mW of total power in a two-stage Yb fiber amplifier.

Mucosal regulatory T cells in airway hyperresponsiveness

Interest in regulatory T cells (Treg) and their role in immune regulation has grown almost exponentially over the last 10 years, though the notion of a suppressive population of T cells has been in existence since the early 1970s. Recent reports have highlighted the potential role of populations of Treg in control of T-cell-mediated inflammation in tissues, including the lung. In particular, there is now evidence to suggest that Treg form a fundamental part of the regulatory axis operating within the respiratory mucosa and that the number of Treg recruited to the airways may be crucial for the inhibition of airways hyperresponsiveness associated with exacerbations of asthma. A discussion of these concepts is the focus of this chapter.

Two-color fiber amplifier for short-pulse, mid-infrared generation

A short-pulse, two-color Yb:fiber laser system has been developed for mid-infrared generation. To date, 20 microW of average power at a wavelength of approximately 18 microm is generated by difference-frequency mixing 300 mW average power from the two-color Yb:fiber amplifier. The mid-infrared power was not limited by two-photon absorption, allowing it to be scaled by increasing the amplifier power.

Multifrequency parametric infrared Raman generation in KGd(WO(4))(2) crystal with biharmonic ultrashort-pulse pumping

Mutlifrequency parametric Raman generation was carried out in a KGd(WO(4))(2) crystal by use of a dual-wavelength Ti:sapphire laser system. It was found that with femtosecond pump pulses the efficiency of Raman generation is low because of the onset of self-phase modulation. The mechanism for suppression of stimulated Raman scattering by self-phase modulation is discussed. Employing 2-ps-long chirped pulses generated four Stokes and one anti-Stokes component.

Mid-infrared pulses generated from the mixing output of an amplified, dual-wavelength Ti:sapphire system

We demonstrate the generation of femtosecond mid-infrared pulses by direct difference-frequency mixing in a AgGaS(2) crystal of two intense pulses from a dual-wavelength oscillator that have been simultaneously amplified in a single regenerative amplifier. A pulse energy of as much as 1.6 muJ was achieved at wavelengths of 9-11 mum.

Role of the low-density lipoprotein receptor-related protein in beta-amyloid metabolism and Alzheimer disease

Deposition of beta-amyloid (A beta), a metabolite of approximately 4 kd of the amyloid precursor protein, is a critical pathological feature in Alzheimer disease. We postulate that deposition reflects an imbalance of A beta synthesis and clearance. Several pathways that impact A beta converge on a single receptor molecule, the low-density lipoprotein receptor-related protein (LRP). This multifunctional receptor is the major neuronal receptor both for apolipoprotein E (apoE, protein; APOE, gene) and for alpha2-macroglobulin (alpha2M, protein; A2M, gene), and it mediates clearance of apoE/A beta and alpha2M/A beta complexes. The LRP also interacts with the amyloid precursor protein itself. In this review, we highlight data that support a role for LRP in A beta metabolism and hypothesize that LRP therefore plays a critical role in Alzheimer disease.

Dual-wavelength chirped-pulse amplification system

We demonstrate a chirped-pulse amplification system that simultaneously amplifies two pulses from a dual-wavelength oscillator in a single regenerative amplifier. The two wavelengths can be tuned from 800 to 890 nm. The total energy of 1.5 mJ can be variably split between the two pulses. The pulses are 150 fs in duration and have 60-fs timing jitter.

Human coagulation factor FVIIa (recombinant) in the management of limb-threatening bleeds unresponsive to alternative therapies: results from the NovoSeven emergency-use programme in patients with severe haemophilia or with acquired inhibitors

This open-label, emergency-use study evaluated the efficacy and safety of activated human coagulation factor VIIa (recombinant) (rFVIIa) (NovoSeven; Novo Nordisk Pharmaceuticals, Inc., New Jersey, USA) in treating limb-threatening joint or muscle bleeds in 17 patients with haemophilia A or B and six patients with acquired inhibitors to factor VIII or factor IX. All patients had previously failed on one or more alternative therapies. rFVIIa administration was effective or partially effective in controlling joint or muscle bleeds in 34 out of 35 (97%) bleeding episodes; in 23 patients, 14 of 17 (82%) muscle bleeds and 16 of 18 (89%) joint bleeds were effectively controlled. These findings suggest that rFVIIa is an effective and well-tolerated therapeutic option in the management of joint or muscle haemorrhage in patients with haemophilia and in patients with acquired inhibitors.

Saving your career in the 21st century

This article addresses the fundamental and dramatic changes that case managers must undergo internally to keep pace with a rapidly and radically changing work environment as we move into the next millennium. The work paradigm is transforming from a model of well-defined job descriptions and clearly articulated career ladders within organizations to a fluid workforce in which individuals must now view themselves as a mobile portfolio of skills responding to particular needs within organizations Hence, case managers must retool their thinking, unlearn old beliefs that hinder success, and learn to manage their careers as microbusinesses within their organizations. This new model is founded on self-responsibility, entrepreneurial aptitude, vision and personal empowerment. Taking charge of one's career and consciously directing it is a dramatic departure from the norm for most individuals. There is a widely held tendency in our culture to define ourselves by our job titles. This is both an antiquated and myopic view that needs to be discarded to succeed in the future. Health care is a dynamic and evolving industry that requires forward-thinking, flexible, solutions-oriented people. The time is upon case managers to undergo a personal renaissance to artfully position themselves for success in the next millennium.

Emotional intelligence: the most potent factor in the success equation

Star performers can be differentiated from average ones by emotional intelligence. For jobs of all kinds, emotional intelligence is twice as important as a person's intelligence quotient and technical skills combined. Excellent performance by top-level managers adds directly to a company's "hard" results, such as increased profitability, lower costs, and improved customer retention. Those with high emotional intelligence enhance "softer" results by contributing to increased morale and motivation, greater cooperation, and lower turnover. The author discusses the five components of emotional intelligence, its role in facilitating organizational change, and ways to increase an organization's emotional intelligence.

Overcome terminal seriousness: let go, laugh, and lighten up!

This article examines physiological and psychological benefits of laughter and humor. These are essential tools that can successfully combat the stress and pressure of the perioperative environment. Used in tandem with "life balancing skills," they can enrich the work arena and help nurses rekindle passion and meaning in their lives.

Balancing life's choices--all dressed up and too many places to go

One of the most common types of stress among people in the health care profession is burnout. Saving lives, supporting people's health, confronting extreme danger, and patching people back together demands an enormous amount of physical and emotional energy. There are several factors that can lead nurses to getting burned out and becoming dissatisfied and unhealthy. As nurses try to juggle too many balls while wearing too many hats, they can get swept up in a rapid-fire pace that leaves them unhappy and disconnected. The many pressures and constant barrage of technology and media have caused many individuals to actively pursue balance in the same way they once sought upward mobility. This article offers practical steps that nurses can take to retool their lives into a meaningful journey of fulfillment and responsible choices, founded on self-insight and reflection.

Possible association of a reduction in cardiovascular events with blood donation

BACKGROUND

The iron hypothesis suggests that females are protected from atherosclerosis by having lower iron stores than men, thus limiting oxidation of lipids.

OBJECTIVE

To test the iron hypothesis by comparing cardiovascular event rates in whole blood donors compared with nondonors.

DESIGN

Prospective cohort with telephone survey follow up.

SETTING

The State of Nebraska, USA.

PARTICIPANTS

A sample was selected from the Nebraska Diet Heart Survey (NDHS) restricting for age > or = 40 years and absence of clinically apparent vascular diseases at time of enrollment in to NDHS (1985-87).

MAIN OUTCOME MEASURES

The occurrence of cardiovascular events (myocardial infarction, angina, stroke), procedures (angioplasty, bypass surgery, claudication, endarterectomy), nitroglycerin use, or death (all cause mortality), and level of blood donation.

RESULTS

Participants were 655 blood donors and 3200 non-donors who differed in education, physical activity, diabetes, and frequency of antihypertensive treatment; 889 were lost to follow up. Sixty four donors and 567 non-donors reported cardiovascular events (crude odds ratio = 0.50, 95% confidence interval (CI) 0.38-0.66). The benefit of donation was confined to non-smoking males (adjusted odds ratio 0.67, 95% CI 0.45-0.99). Benefit was limited to current donors (the most recent three years). No additional benefit resulted from donating more than once or twice over three years.

CONCLUSION

In support of the iron hypothesis, blood donation in non-smoking men in this cohort was associated with reduced risk of cardiovascular events. A randomised clinical trial is warranted to confirm these findings as the observed personal health benefit of donation has public policy ramifications.

Virtual reality for the treatment of autism

Autism is a mental disorder which has received attention in several unrelated studies using virtual reality. One of the first attempts was to diagnose children with special needs at Tokyo University using a sandbox playing technique. Although operating the computer controls proved to be too difficult for the individuals with autism in the Tokyo study, research at the University of Nottingham, UK, is successful in using VR as a learning aid for children with a variety of disorders including autism. Both centers used flat screen computer systems with virtual scenes. Another study which concentrated on using VR as a learning aid with an immersive headset system is described in detail in this chapter. Perhaps because of the seriousness of the disorder and the lack of effective treatments, autism has received more study than attention deficit disorders, although both would appear to benefit from many of the same technology features.

Brief report: two case studies using virtual reality as a learning tool for autistic children

The children complied with most requests. Some of our teaching goals were limited by technology or space while others were limited by the difficulty of presenting a task to the children in a way that was understandable within their environment. However, the opportunity to introduce this technology to children was an important first step in exploring the potential VR offers to understanding the perceptual processes involved in autism. Our results indicate that the will accept a VR helmet and wear it, identify familiar objects and qualities of these objects in their environment while using the helmet, and locate and move toward objects in their environment while wearing the helmet. More research is necessary to verify the potential in this area, especially to discover if learning experiences through VR generalize to other environments, but it appears virtual reality may provide a useful tool for furthering our understanding of autism and guiding efforts at treatment and intervention.

Descriptive epidemiology of Parkinson's disease through proxy measures

BACKGROUND AND OBJECTIVE

In preparation for analytic study we undertook to describe areas of relative excess and deficit of Parkinson's Disease (PD) in Nebraska and tested two methodologic tools for inexpensive assessment of descriptive epidemiology of PD.

METHODS

In lieu of large-scale population screening and diagnosis, we obtained sales information of anti-PD drugs in the state in 1988-1990 as well as listings of all people dying from 1984 to 1993 who had Parkinson's Disease mentioned anywhere on their death certificate. The anti-PD drug sales data are intended as a proxy for prevalence, while the death certificate data are intended as a proxy for incidence.

RESULTS

Sales divided by population over age 54 indicates where anti-PD drug sales differ from expected. We found high correlation of drug sales rates with several farming exposures. Age-adjusted death rates, however, showed a low degree of association with sales or farming variables. This may be attributable to differences in death certificate completion or in underlying incidence versus prevalence.

CONCLUSIONS

These techniques provide a useful tool for delineating possible differences in incidence and prevalence. While not as accurate as full community survey with expert diagnosis, they are not as expensive, and can be followed by local cluster investigations and individual-level etiologic studies to test hypotheses resulting from the initial study.

Amyotrophic lateral sclerosis and occupational history. A pilot case-control study

OBJECTIVE

To assess the association of a number of occupational and industrial exposures with amyotrophic lateral sclerosis (ALS).

DESIGN

A case-control study of ALS cases matched by age and sex to 2 controls each: 1 from a neurologic clinic and 1 from a local community. Exposures were ascertained by questionnaire, and patients were requested before the interview to be to prepared to supply occupational histories.

SETTING

Patients with ALS were enrolled at the University of Minnesota ALS Clinic in Minneapolis.

PATIENTS

Patients with ALS (n = 25) were from the University of Minnesota ALS clinic, and clinic controls (n = 25) were patients with other neuromuscular diseases from the university's Muscle Disease Clinic, selected on the basis of clinic enrollment date nearest to that of the matched case. Clinic controls were principally patients with myopathies. Community controls (n = 25) were selected from the community using a random-digit-dialing protocol matching on the first 5 digits of the case patient's telephone number.

RESULTS

The strongest association with disease was exposure to welding or soldering materials (odds ratio, 5.0) and the welding industry (odds ratio, 5.3). Electric plating showed a high odds ratio of 8 (95% confidence interval, 0.9-72.0), but low statistical significance (P < .07) Several exposures or industries, while not statistically different, showed enough difference that to ignore them might lead to a Type II error, a result of the pilot nature and small sample size. These included paint or pigment manufacturing, the petroleum industry, the printing industry, and shipbuilding.

CONCLUSIONS

The association with welding, soldering, and the welding industry is strong and suggests a need for further work. This is despite the small numbers studied, thus making most industrial or occupational exposures too limited to draw conclusions or detect associations. Perhaps the most obvious candidate from the welding, soldering exposure for a common toxin would be lead. Other suggestions of risk were seen for paint or pigment manufacture, shipbuilding, electric plating, and the dairy industry. The degree of association for these, while high, is not statistically significant, and suggests that there may be 1 or more environmental toxins common to those industries that need more precise measurement.

Applying Watson's Theory for Caring among elders

Caring is emerging as a significant concept for the nursing profession, and it is rapidly influencing nursing practice. In older adult care, where reductionistic medical cures are often not wanted or necessary, it seemed timely to take a closer look at Dr. Jean Watson's Theory of Human Caring. The author and a volunteer used a particular format designed by Lee Glickstein called "Laughing Spirit Listening Circles" to apply Watson's theory with six elderly women weekly over a four-week period. The main goals the volunteers had in creating this group was simply to listen to the women share their stories with one another, to be as present with them as possible, to not be directive in the group, but to be "in the flow" with whatever topics and issues emerged. Another purpose the author had in conducting these sessions was to receive feedback from the participants regarding this style of nursing practice. At the last session participants offered comments regarding their experience in this group with suggestions for how to include others. Unsolicited, the participants had much to say regarding their own personal experience at the retirement community around this issue of "presence" and "caring."

Physical activity, trauma, and ALS: a case-control study

AIMS

The association of trauma and physical activity with ALS is controversial. We explored the relation in a pilot case-control study.

MATERIAL AND METHODS

ALS patients were selected from a university muscle disease clinic and paired with two matched controls: one from the clinic, but having different diseases, and one from the community.

RESULTS

We found several strong and statistically significant differences between ALS cases and the matched controls. These included severe head, neck and back injury (OR = 5.3), the frequency of sweating in work (OR = 1.6) or leisure activity (also OR = 1.6), and earning a school letter (OR = 3.1). Other measures of trauma and activity, while not achieving statistical significance (p < 0.05), were in accord with these findings.

DISCUSSION

Possible explanations include trauma and vigorous exercise precipitating ALS; trauma as an early sign of disease; or a third factor associated with ALS predisposing to injury.

CONCLUSIONS

Severe head, neck, and back injury and frequency of sweating both in work and leisure activity showed a strong association with ALS. Further study could test narrower and less common exposures with greater statistical power.

Expression of the very low-density lipoprotein receptor (VLDL-r), an apolipoprotein-E receptor, in the central nervous system and in Alzheimer's disease

The very low density lipoprotein receptor (VLDL-r) is a cell-surface molecule specialized for the internalization of multiple diverse ligands, including apolipoprotein E (apoE)-containing lipoprotein particles, via clathrin-coated pits. Its structure is similar to the low-density lipoprotein receptor (LDL-r), although the two have substantially different systemic distributions and regulatory pathways. The present work examines the distribution of VLDL-r in the central nervous system (CNS) and in relation to senile plaques in Alzheimer disease (AD). VLDL-r is present on resting and activated microglia, particularly those associated with senile plaques (SPs). VLDL-r immunoreactivity is also found in cortical neurons. Two exons of VLDL-r mRNA are differentially spliced in the mature receptor mRNA. One set of splice forms gives rise to receptors containing (or lacking) an extracellular O-linked glycosylation domain near the transmembrane portion of the molecule. The other set of splice forms appears to be brain-specific, and is responsible for the presence or absence of one of the cysteine-rich repeat regions in the binding region of the molecule. Ratios of the receptor variants generated from these splice forms do not differ substantially across different cortical areas or in AD. We hypothesize that VLDL-r might contribute to metabolism of apoE and apoE/A beta complexes in the brain. Further characterizations of apoE receptors in Alzheimer brain may help lay the groundwork for understanding the role of apoE in the CNS and in the pathophysiology of AD.

Ligand-toxin hybrids directed to the alpha 2-macroglobulin receptor/low density lipoprotein receptor-related protein exhibit lower toxicity than native Pseudomonas exotoxin

Pseudomonas exotoxin (PE) binds the heavy chain of the alpha2-macroglobulin receptor/low density lipoprotein receptor-related protein (LRP). To understand the significance of this interaction, novel toxin-derived gene fusions were constructed with two ligands that also bind this receptor. A 39-kDa cellular protein, termed RAP, binds LRP with high affinity and often co-purifies with it. Two RAP toxins were constructed, one with PE and one with diphtheria toxin (DT). RAP, which replaced the toxins binding domains, was combined with each of the corresponding translocating and ADP-ribosylating domains. Both RAP-toxins bound LRP with an apparent higher affinity than native PE. Despite this, RAP-PE and DT-RAP were less toxic than native PE. Apparently, RAP-toxin molecules bound and entered cells but used a pathway that afforded only low efficiency of toxin transport to the cytosol. This was evident because co-internalization with adenovirus increased the toxicity of RAP-toxins by 10-fold. We speculate that the high affinity of RAP binding may not allow the toxin's translocating and ADP-ribosylating domains to reach the cytosol but rather causes the toxin to take another pathway, possibly one that leads to lysosomes. To test this hypothesis, additional RAP-PE fusions were constructed. N-terminal or C-terminal fragments of RAP were joined to PE to produce two novel fusion proteins which were likely to have reduced affinity for LRP. Both of these shorter fusion proteins exhibited greater toxicity than full-length RAP-PE. A second ligand-toxin gene fusion was constructed between plasminogen activator inhibitor type 1 and DT. DT-plasminogen activator inhibitor type 1 formed a complex with tissue-type plasminogen activator and inhibited its proteolytic activity. However, like the RAP-toxins, this hybrid was less toxic for cells than native PE.

Regulation of T-cell activation in the lung: isolated lung T cells exhibit surface phenotypic characteristics of recent activation including down-modulated T-cell receptors, but are locked into the G0/G1 phase of the cell cycle

Peripheral lung tissue contains large numbers of T cells, strategically located for immune surveillance at the blood-air interface. Given the intensity of antigenic exposure at this site, it is clear that local T-cell activation events require strict control, in order to maintain tissue homeostasis. How this control is achieved in this unique tissue microenvironment is unknown, and the present study sought to elucidate the process via detailed analysis of the surface phenotypic characteristics of freshly isolated lung T cells. We report below that these cells display typical characteristic of 'postactivation', notably elevated basal Ca2+ concentrations, down-modulated T-cell receptors, expression of Ia and 'late' activation antigens and concomitant CD4/CD8. However, levels of interleukin-2 receptor and CD2 expression were below those expected of 'activated' T-cell populations, and virtually all of the cells were found to be in the G0/G1 phases of the cell cycle. These properties bear a remarkable similarity to those of T cells activated in the presence of endogenous tissue (alveolar) macrophages from the lung (see accompanying paper). We hypothesize that they reflect the in vivo operation of an endogenous macrophage-mediated T-cell anergy-induction process, the function of which is to limit the local clonal expansion of T cells in peripheral lung tissue after in situ activation.

Regulation of T-cell activation in the lung: alveolar macrophages induce reversible T-cell anergy in vitro associated with inhibition of interleukin-2 receptor signal transduction

Alveolar macrophages (AM) are recognized as archetypal 'activated' macrophages with respect to their capacity to suppress T-cell responses to antigen or mitogen, and this function has been ascribed an important role in the maintenance of local immunological homeostasis at the delicate blood:air interface. The present study demonstrates that this suppression involves a unique form of T-cell anergy, in which 'AM-suppressed' T cells proceed normally through virtually all phases of the activation sequence including Ca2+ flux, T-cell receptor (TCR) modulation, cytokine [including interleukin-2 (IL-2)] secretion and IL-2 receptor (IL-2R) expression. However, the 'suppressed' T cells fail to up-regulate CD2, and do not re-express normal levels of TCR-associated molecules after initial down-modulation; moreover, they are unable to transduce IL-2 signals leading to phosphorylation of IL-2R-associated proteins, and remained locked in G0/G1. The induction of this form of anergy is blocked by an NO-synthase inhibitor, and is reversible upon removal of AM from the T cells, which then proliferate in the absence of further stimulation. We hypothesize that this mechanism provides the means to limit the magnitude of local immune responses in this fragile tissue microenvironment, while preserving the capacity for generation of immunological memory against locally encountered antigens via clonal expansion of activated T cells after their subsequent migration to regional lymphoid organs. In an accompanying paper, we demonstrate that a significant proportion of T cells freshly isolated from lung exhibit a comparable surface phenotype.

In utero treatment of fetal goitrous hypothyroidism caused by maternal Graves' disease

We present two cases of maternal Graves' disease complicated by fetal goitrous hypothyroidism. Both patients had elevated maternal thyroid-stimulating immunoglobulin and thyrotropic-binding inhibitory immunoglobulin antibody titers. Diagnosis of fetal hypothyroidism was made by cordocentesis, and serial injections of thyroxine into the amniotic fluid resulted in return to normal of fetal thyroid size and function at birth. Significance of in utero management of fetal hypothyroidism is discussed.

Level of receptor-associated protein moderates cellular susceptibility to pseudomonas exotoxin A

Pseudomonas exotoxin A (PE) enters mammalian cells via a receptor-mediated endocytic pathway. The initial step in this pathway is binding to the multiligand receptor termed the alpha 2-macroglobulin receptor/low-density lipoprotein receptor-related protein (LRP). Binding of toxin, and of the many other ligands that bind to LRP, is blocked by the addition of a 39-kDa receptor-associated protein (RAP). Here we show that approximately 40% of the cell-associated LRP is on the surface of toxin-sensitive mouse LM fibroblasts and thus accessible for toxin internalization. The remainder is located intracellularly, primarily in the Golgi region. Mammalian cells exhibit a wide range of sensitivity to PE. To investigate possible reasons for this, we examined the expression levels of both LRP and RAP. Results from a variety of cell lines indicated that there was a positive correlation between LRP expression and toxin sensitivity. In the absence of LRP, cells were as much as 200-fold more resistant to PE compared with sensitive cells. A second group of resistant cells expressed LRP but had a high level of RAP. Thus, a toxin-resistant phenotype would be expected when cells expressed either low levels of LRP or high levels of LRP in the presence of high levels of RAP. We hypothesize that RAP has a pivotal role in moderating cellular susceptibility to PE.

Prenatal diagnosis and management of fetal goiter caused by maternal Grave's disease

We present a case of maternal Grave's disease associated with fetal goitrous hyperthyroidism. Fetal goiter was diagnosed by ultrasound and diagnosis of fetal hyperthyroidism was established by umbilical blood sampling. Fetus was successfully treated by increasing maternal propylthiouracil dosage. Fetal thyroid status was normal at birth. Role of sonography and umbilical blood sampling in management of fetal goiter complicated with maternal Grave's disease is discussed.

Age-specific reference ranges for serum prostate-specific antigen

OBJECTIVES

To assess the relationship of the distribution of serum prostate-specific antigen (PSA) to age in a population of subjects for whom PSA levels were determined as part of a health fair.

METHODS

Between March 19 and March 28, 1993, 1716 men aged 40 to 79 years from eastern Nebraska who participated in "The Health Fair of the Midlands" provided blood for serum PSA determination.

RESULTS

Serum PSA concentration was correlated with patient age, with the observed 95th percentile increasing from 1.5 ng/mL for subjects 40 to 44 years of age to 7.7 ng/mL for subjects 75 to 79 years of age. Variability in serum PSA concentrations increased with increasing age. Taking this heteroscedasticity into account provided the following upper limits of normal (95th percentiles) for serum PSA: age 40 to 49, 1.5; age 50 to 59, 2.6; age 60 to 69, 4.4; age 70 to 79, 7.5.

CONCLUSIONS

Previously published age-specific reference ranges did not consider the increasing variability of PSA concentration with age and have upper limits of normal that are too high for subjects under age 60 and may be too low for subjects aged 70 to 79. Upper reference ranges of 1.5 ng/mL for subjects aged 40 to 49, 2.5 ng/mL for subjects aged 50 to 59, 4.5 ng/mL for subjects aged 60 to 69, and 7.5 ng/mL for subjects aged 70 to 79 years provide specificity near 95%.

Pseudomonas exotoxin-mediated selection yields cells with altered expression of low-density lipoprotein receptor-related protein

The alpha 2-macroglobulin (alpha 2M) receptor/low-density lipoprotein receptor-related protein (LRP) is important for the clearance of proteases, protease-inhibitor complexes, and various ligands associated with lipid metabolism. While the regulation of receptor function is poorly understood, the addition of high concentrations of the 39-kD receptor-associated protein (RAP) to cells inhibits the binding and/or uptake of many of these ligands. Previously, we (Kounnas, M.Z., R.E. Morris, M.R. Thompson, D.J. FitzGerald, D.K. Strickland, and C.B. Saelinger. 1992. J. Biol. Chem. 267:12420-12423) [corrected] showed that Pseudomonas exotoxin (PE) could bind immobilized LRP. Also, the addition of RAP blocked toxin-mediated cell killing. These findings suggested that PE might use LRP to gain entry into toxin-sensitive cells. Here we report on a strategy to select PE-resistant lines of Chinese hamster ovary cells that express altered amounts of LRP. An important part of this strategy is to screen PE-resistant clones for those that retain sensitivity to both diphtheria toxin and to a fusion protein composed of lethal factor (from anthrax toxin) fused to the adenosine diphosphate-ribosylating domain of PE. Two lines, with obvious changes in their expression of LRP, were characterized in detail. The 14-2-1 line had significant amounts of LRP, but in contrast to wild-type cells, little or no receptor was displayed on the cell surface. Instead, receptor protein was found primarily within cells, much of it apparently in an unprocessed state. The 14-2-1 line showed no uptake of chymotrypsin-alpha 2M and was 10-fold resistant to PE compared with wild-type cells. A second line, 13-5-1, had no detectable LRP mRNA or protein, did not internalize alpha 2M-chymotrypsin, and exhibited a 100-fold resistance to PE. Resistance to PE appeared to be due to receptor-specific defects, since these mutant lines showed no resistance to a PE chimeric toxin that was internalized via the transferrin receptor. The results of this investigation confirm that LRP mediates the internalization of PE.