Primum Non Nocere and the 5 Rights.

Overutilization of hyperbaric oxygen therapy (HBOT) is commonplace and primarily associated with outpatient wound care. While the number of hospitals providing HBOT is at an all-time high, the number of those willing to treat patients in immediate need is at an all-time low. Huge areas of the country, including major population areas, are now completely devoid of 24/7 HBOT availability and inpatient access. Purchasers of healthcare, including the Centers for Medicare and Medicaid Services, have become increasingly concerned to the point that several strategies have been introduced to constructively deal with this issue. This commentary serves as a counterpoint to concerns that one such approach, prior authorization of elective indications, adversely delays medically necessary care. The historical evolution of HBOT practice will be described to underscore how this problem has become so widespread and, to date, largely unchecked. It will also address the paradoxical national crisis of access for emergencies.

Epaulet size and current condition in red-winged blackbirds: examining a semistatic signal, testosterone, immune function, and parasites.

Some sexually selected signals are thought to convey information about the current condition and genetic/epigenetic quality of the individual signaling, including the ability to resist parasites. However, it is unclear whether semistatic sexual signals that develop periodically and remain stable over protracted periods, such as avian breeding plumage, can relate to measures of current condition and health. We examined a semistatic signal (wing epaulet size) in male red-winged blackbirds (Agelaius phoeniceus) during the breeding season and looked for relationships between this trait and circulating testosterone (T), hematocrit, bacteria-killing ability (BKA) of the blood, and the infection status, richness, and abundance of four functional categories of parasite. We found that epaulet size was positively related to circulating levels of T and ectoparasite infections. We found no relationships between T and parasite infections. In adult males there was a negative relationship between T and BKA, whereas in yearling males there was no relationship. We found no evidence for a general reduction in immunocompetence in males with larger epaulets but rather an increase in susceptibility to specific types of parasites. Our results suggest that semistatic signals can be linked to measures of current condition, and we postulate that these relationships are modulated via activity levels related to breeding-season activities.

Immune function in an avian brood parasite and its nonparasitic relative.

Organisms that breed multiple times must trade off resources between current and future reproduction. In many species, sexual selection can lead to reduced levels of immune function in males because they invest heavily in current reproduction at the expense of self-maintenance. Much less is known about whether the same trend is seen in species such as the brood-parasitic brown-headed cowbird Molothrus ater (hereafter "cowbird"), in which females invest heavily in current reproduction. We examined two measures of immune function (bactericidal capacity of the plasma and the phytohemagglutinin swelling response) and baseline levels of corticosterone in both sexes of the cowbird and its nonparasitic relative the red-winged blackbird Agelaius phoeniceus (hereafter "redwing") during the breeding and subsequent nonbreeding seasons. We found that female cowbirds exhibited significantly lower levels of both measures of immune function than did male cowbirds and female redwings during the breeding season but had comparable levels during the nonbreeding season. Female redwings, in contrast, exhibited higher or comparable levels of immune function when compared with male redwings during the breeding season. In conjunction with published accounts documenting significantly higher rates of mortality for female cowbirds compared with male cowbirds and the fact that female cowbirds produce very high numbers of eggs (25-65) in a single breeding season, our results suggest that female cowbirds invest heavily in current reproduction at the expense of self-maintenance.

When less is best: female brown-headed cowbirds prefer less intense male displays.

Sexual selection theory predicts that females should prefer males with the most intense courtship displays. However, wing-spread song displays that male brown-headed cowbirds (Molothrus ater) direct at females are generally less intense than versions of this display that are directed at other males. Because male-directed displays are used in aggressive signaling, we hypothesized that females should prefer lower intensity performances of this display. To test this hypothesis, we played audiovisual recordings showing the same males performing both high intensity male-directed and low intensity female-directed displays to females (N = 8) and recorded the females' copulation solicitation display (CSD) responses. All eight females responded strongly to both categories of playbacks but were more sexually stimulated by the low intensity female-directed displays. Because each pair of high and low intensity playback videos had the exact same audio track, the divergent responses of females must have been based on differences in the visual content of the displays shown in the videos. Preferences female cowbirds show in acoustic CSD studies are correlated with mate choice in field and captivity studies and this is also likely to be true for preferences elucidated by playback of audiovisual displays. Female preferences for low intensity female-directed displays may explain why male cowbirds rarely use high intensity displays when signaling to females. Repetitive high intensity displays may demonstrate a male's current condition and explain why these displays are used in male-male interactions which can escalate into physical fights in which males in poorer condition could be injured or killed. This is the first study in songbirds to use audiovisual playbacks to assess how female sexual behavior varies in response to variation in a male visual display.

Sex-specific variation in brown-headed cowbird immunity following acute stress: a mechanistic approach.

There is some discrepancy in the literature regarding whether acute stress is immunostimulatory or immunosuppressive. Studies of domesticated (laboratory and food) animals and humans typically indicate that acute stress is immunostimulatory, whereas studies of non-domesticated species document both immunostimulatory and immunosuppressive results. Few studies have examined the mechanisms responsible for changes in immune activity in species other than those classically used in laboratory research. We examined the effect of both acute stress and exogenous corticosterone (CORT) on the bactericidal capacity (BC) of blood plasma from captive, wild-caught brown-headed cowbirds (Molothrus ater) to determine if CORT is responsible for changes in levels of immune activity. We conducted "stress tests" in which we handled birds to elicit a stress response and then measured the birds' total CORT and BC at 30 or 90 min post-stressor. We also conducted non-invasive tests in which we administered exogenous CORT by injecting it into mealworms that were fed to the cowbirds remotely. Total, free, and bound CORT levels, corticosteroid binding globulins (CBGs), and BC at 7 or 90 min post-mealworm ingestion were measured. Both males and females exhibited significant increases in total CORT following handling stress and the administration of exogenous CORT. Experimental males and females also exhibited a significant increase in CBG capacity at 7 min post-mealworm ingestion compared to controls. Male cowbirds exhibited a significant decline in their BC following both handling stress and the administration of exogenous CORT whereas female cowbirds exhibited no decline under either condition. Female CBG levels were not different than those of males, suggesting that differences in BC could be due to differences between the sexes in the number of corticosteroid receptors which, along with CBGs, regulate the stress response. Female cowbirds may modulate their stress response as an adaptive life-history strategy for maximizing current reproduction.

Bilateral auricular seromas: a case report and review of the literature.

Hematomas, pseudocysts, and seromas are all part of the differential diagnosis of auricular swellings. Seromas are benign collections of serous fluid that have a tendency to recur. The fluid accumulates in the space between the dermis and perichondrium of the ear. We describe what we believe is the first case of spontaneous bilateral auricular seromas to be reported in the literature. One of the seromas resolved in 4 weeks without treatment, and the other resolved with incision and drainage. It is important for physicians to be aware of auricular seromas when considering the differential diagnosis of an auricular swelling, and to understand the various treatment options.

Persistence of host defence behaviour in the absence of avian brood parasitism.

The fate of host defensive behaviour in the absence of selection from brood parasitism is critical to long-term host-parasite coevolution. We investigated whether New World Bohemian waxwings Bombycilla garrulus that are allopatric from brown-headed cowbird Molothrus ater and common cuckoo Cuculus canorus parasitism have retained egg rejection behaviour. We found that egg rejection was expressed by 100 per cent of Bohemian waxwings. Our phylogeny revealed that Bohemian and Japanese waxwings Bombycilla japonica were sister taxa, and this clade was sister to the cedar waxwing Bombycilla cedrorum. In addition, there was support for a split between Old and New World Bohemian waxwings. Our molecular clock estimates suggest that egg rejection may have been retained for 2.8-3.0 Myr since New World Bohemian waxwings inherited it from their common ancestor with the rejecter cedar waxwings. These results support the 'single trajectory' model of host-brood parasite coevolution that once hosts evolve defences, they are retained, forcing parasites to become more specialized over time.

Conserving migratory land birds in the new world: do we know enough?

Migratory bird needs must be met during four phases of the year: breeding season, fall migration, wintering, and spring migration; thus, management may be needed during all four phases. The bulk of research and management has focused on the breeding season, although several issues remain unsettled, including the spatial extent of habitat influences on fitness and the importance of habitat on the breeding grounds used after breeding. Although detailed investigations have shed light on the ecology and population dynamics of a few avian species, knowledge is sketchy for most species. Replication of comprehensive studies is needed for multiple species across a range of areas, Information deficiencies are even greater during the wintering season, when birds require sites that provide security and food resources needed for survival and developing nutrient reserves for spring migration and, possibly, reproduction. Research is needed on many species simply to identify geographic distributions, wintering sites, habitat use, and basic ecology. Studies are complicated, however, by the mobility of birds and by sexual segregation during winter. Stable-isotope methodology has offered an opportunity to identify linkages between breeding and wintering sites, which facilitates understanding the complete annual cycle of birds. The twice-annual migrations are the poorest-understood events in a bird's life. Migration has always been a risky undertaking, with such anthropogenic features as tall buildings, towers, and wind generators adding to the risk. Species such as woodland specialists migrating through eastern North America have numerous options for pausing during migration to replenish nutrients, but some species depend on limited stopover locations. Research needs for migration include identifying pathways and timetables of migration, quality and distribution of habitats, threats posed by towers and other tall structures, and any bottlenecks for migration. Issues such as human population growth, acid deposition, climate change, and exotic diseases are global concerns with uncertain consequences to migratory birds and even less-certain remedies. Despite enormous gaps in our understanding of these birds, research, much of it occurring in the past 30 years, has provided sufficient information to make intelligent conservation efforts but needs to expand to handle future challenges.

Sex differences in the effects of captivity on hippocampus size in brown-headed cowbirds (Molothrus ater obscurus).

In brood parasitic cowbirds, hippocampus (Hp) size is correlated with environmental spatial memory demands. Searching for host nests is the presumed causal factor influencing cowbird Hp size, because Hp volumes vary across species, sexes, and seasons according to nest-searching participation. Brown-headed cowbirds have female-only nest searching and, at least in the eastern subspecies, a larger Hp in females than in males, suggesting that nest searching influences cowbird Hp size. We predicted that female brown-headed cowbirds housed in aviaries lacking host nests would have a smaller Hp than wild-caught females whereas males would be unaffected. We found that the Hp was smaller in captive females, but not males, compared to their wild-caught counterparts. This did not appear to be due to general effects of an impoverished environment on all brain regions. Our results imply that interruption of nest searching in cowbirds prevents seasonal increase in Hp size in females. Future studies should isolate which behavioral differences between wild and captive birds contributed to captivity-induced changes in Hp volume in females while not affecting males.

Clinical outcomes for the elderly patient receiving a tracheotomy.

BACKGROUND: Tracheotomies are routinely performed for severely ill and elderly patients with respiratory failure. This intervention is questioned, given the poor survival rate in this group. Outcomes analysis is performed after tracheotomy. METHODS: This is a retrospective study of 78 elderly patients, who received tracheotomies for respiratory failure. Pretracheotomy data (age, length of oral intubation, and DNR status) were collected. Outcomes analyzed during the same admission as the tracheotomy included death versus discharge, ventilator dependence, vocal function, route of feeding, decannulation, and ICU discharge disposition. RESULTS: The mean age was 77.6 +/- 11 years (median, 79 years) and patients were intubated for 16.7 +/- 9 days. Forty-two percent (n = 33) obtained DNR orders after tracheotomy, and 8% (n = 6) before tracheotomy. Seventy-one percent of patients (n = 55) had gastrostomy tubes placed. Fifty-six percent of patients (n = 44) died after tracheotomy; median time from tracheotomy to death was 31 days. After tracheotomy, 53 % (n = 41) remained at least partially ventilator dependent, 18 % (n = 14) regained consistent vocal function, and 13 % (n = 10) were decannulated. For those who died, 27 % (n = 12) died without leaving the ICU. CONCLUSION: These data demonstrate that a large proportion of elderly, severely ill patients with respiratory failure suffer poor outcomes after tracheotomy. More stringent criteria are necessary for performing the tracheotomy in this patient population.

Relic behaviours, coevolution and the retention versus loss of host defences after episodes of avian brood parasitism.

Most previous studies of brood parasitism have stressed that host defences, such as egg recognition, are lost in the absence of parasitism. Such losses could result in coevolutionary cycles in which parasites shift away from well-defended hosts only to switch back to them later at a time when these hosts have lost much or all of their defences and the parasite's current hosts have built up effective defences. However, the alternative 'single trajectory' model predicts that parasites rarely switch back to old hosts because ex-hosts retain egg recognition for long periods in the absence of parasitism. If true, egg recognition by the host may be a 'relic behaviour', because in the absence of parasitism its adaptive value is close to neutral. Using artificial nonmimetic eggs, I tested for egg recognition in two populations that are currently unparasitized but that are descended from lineages likely to have been parasitized in the past: the grey catbird, Dumetella carolinensis, on Bermuda and the loggerhead shrike, Lanius ludovicianus, in California. Both of these populations showed long-term retention, ejecting nonmimetic eggs at rates of nearly 100%. Because potential present-day selection pressures, such as conspecific parasitism, do not explain this egg recognition, Bermuda catbirds apparently retain recognition from North American conspecifics that were cowbird hosts before colonizing Bermuda and shrikes retain recognition from Old World congeners that were hosts of cuckoos. Retention is also indicated by passerines in California and the Caribbean that had high rejection rates of nonmimetic eggs before coming into contact with cowbirds. These new data suggest that both the coevolutionary cycles and single trajectory models have importance and that rejection behaviour can have insignificant costs, which is consistent with evolutionary lag explanations for the acceptance of parasitic eggs shown by some cuckoo and many cowbird hosts. Copyright 2001 The Association for the Study of Animal Behaviour.

KNOWN SECONDARY CONTACT AND RAPID GENE FLOW AMONG SUBSPECIES AND DIALECTS IN THE BROWN-HEADED COWBIRD.

We analyze geographic variation in morphology for Sierra Nevadan populations of Brown-headed Cowbirds (Molothrus ater) in relation to two levels of geographic structure of populations: 1) subspecies and 2) vocal dialects. Two morphologically distinct subspecies occupy opposite slopes of the Sierra Nevada: M. a artemisiae on the east slope is larger than M. a. obscurus on the west slope, and its juveniles have predominantly white versus yellow rictal (bill) flanges. Populations of obscurus moved into California from the lower Colorado River around 1900 and invaded the western Sierra during the 1930's. A relatively constant type of flight whistle occurs in obscurus populations up to 700 km apart, but east-slope artemisiae are divided into many distinct dialects. The means of seven morphological measurements and of principal component 1 (i.e., body size) for 2,287 individuals show similar clinal patterns for adult males, yearling males, and females over a 60-km north-south transect along the eastern Sierra Nevada: large sizes occur at the southernmost study site at Bishop, decrease clinally to the north to Mammoth Lakes, and then increase clinally to the north from Mammoth Lakes to the northernmost site at Lee Vining. This reversal in cline slope is reiterated for variation in the frequency of white-flanged juveniles. Our data do not support adaptive explanations for the clines. Rather, the most parsimonious explanation is that there has been flow of obscurus genes into artemisiae from the west slope across the crest of the Sierra Nevada into the Mammoth Lakes area. Concordantly, the Sierran crest at Mammoth Lakes is considerably lower than any other point within about 80 km to the north or 180 km to the south. Two other findings strongly support this interpretation. First, wing lengths of our longest-winged samples (at Bishop and Lee Vining) are significantly shorter than those of cowbirds collected in the same region between 1912 and 1922. Second, the wing lengths of Mammoth Lakes adult males and females during 1978-1981 are significantly larger than those of the 1982-1985 period. This putative hybridization must have been rapid, as there have been fewer than 50 years since secondary contact could have occurred. Calculation of the gene-flow parameter Ι of Endler (1977) indicates that the gene-flow rate reported here is higher than for nearly all of the species he surveyed. This gene flow occurs between two subspecies with different flight whistles and across several cowbird flight-whistle dialects within artemisiae. Therefore, vocal differences among these dialects do not appear to be a strong deterrent to gene flow.

COEVOLUTION AND AVIAN BROOD PARASITISM: COWBIRD EGGS SHOW EVOLUTIONARY RESPONSE TO HOST DISCRIMINATION.

The Rufous Hornero (Furnarius rufus) is an important host of the brood parasitic Shiny Cowbird (Molothrus bonariensis) in Uruguay, but not in nearby Buenos Aires Province, Argentina. Eggs of the Shiny Cowbird are extremely variable in size, and horneros eject cowbird eggs with widths less than about 88% of the widths of their own eggs. Uruguayan cowbird eggs are, on average, 12% larger than those from Buenos Aires, a geographic pattern in egg size that corresponds to the pattern of successful host use. Uruguayan cowbird eggs are also wider per unit volume than eggs from Buenos Aires. Allometric analyses of egg width and volume indicate that this shape change is apparently an evolutionary response to selection exerted by the hornero. Such a response is absent in Buenos Aires because interactions between the cowbird and the hornero are probably of recent origin there.