Steroid synthesizing cellular sites in the ovary of the domestic pigeon Columba livia (Gmelin): a histochemical study.

Synopsis The ovary of the domestic pigeon,Columba livia, has been assayed histochemically for the localization of ⁵-3-hydroxysteroid dehydrogenase (⁵-3-HSDH), 17-hydroxysteroid dehydrogenase (17-HSDH), 11-hydroxysteroid dehydrogenase (11-HSDH), glucose-6-phosphate dehydrogenase (G6P-DH) and NADH-diaphorase activities during different periods of the reproductive cycle. ⁵-3-HSDH, 17-HSDH, 11-HSDH, G6P-DH and NADH-diaphorase activity was found in the theca interna of growing, atretic and postovulatory follicles, the granulosa of ovulatory, atretic and postovulatory follicles, and interstitial gland cells during the pre-incubation and the laying periods. During the incubation and squab feeding periods only ⁵-3-HSDH, G6P-DH and NADH-diaphorase activities were observed in the above mentioned cells. The steroidogenic potential of atretic follicles depends upon the type of atresia a follicle undergoes.     

Enhancement of forest canopy research,education, and conservation in the new millennium

Study of the forest canopy has reached a critical stage in its development from a young frontier area of study to a vibrant and coalescing field of investigation and communication. Many current environmental and social issues at global scales (e.g., environmental change, acid deposition, loss of biodiversity) are related directly to our knowledge of forest canopies. I present six activities that are needed to help the vibrant and growing field of forest canopy studies progress efficiently. Enabling canopy researchers to communicate with each other and with those outside our field is an important element to address these issues. The establishment of a graduate-level training program is also a high priority to generate and maintain a healthy discipline. Formal procedures to identify particular forest sites of critical concern should be initiated, and these should include communication of prioritized sites to conservation groups and policy makers. Instilling a sense of wonder and appreciation for organisms and interactions in non-scientists is another important avenue for forest canopy conservation.     

Growth,Net Production,Litter Decomposition,and Net Nitrogen Accumulation by Epiphytic Bryophytes in a Tropical Montane Forest1

To understand the ecological roles of epiphytic bryophytes in the carbon (C) and nitrogen (N) cycles of a tropical montane forest, we used samples in enclosures to estimate rates of growth, net production, and N accumulation by shoots in the canopy, and litterbags, to estimate rates of decomposition and N dynamics of epiphytic bryophyte litter in the canopy and on the forest floor in Monteverde, Costa Rica. Growth of epiphytic bryophytes was estimated at 30.0–49.9 percent/yr, net production at 122–203 g/m²/yr, and N accumulation at 1.8–3.0 g N/m²/yr. Cumulative mass loss from litterbags after one and two years in the canopy was 17 ± 2 and 19 ± 2 percent (mean ± 1 SE) of initial sample mass, respectively, and mass loss from litter and green shoots in litterbags after one year on the forest floor was 29 ± 2 and 45 ± 3 percent, respectively. Approximately 30 percent of the initial N mass was released rapidly from litter in both locations. Nitrogen loss from green shoots on the forest floor was greater; about 47 percent of the initial N mass was lost within the first three months. There was no evidence for net N immobilization by litter or green shoots, but the remaining N in litter was apparently recalcitrant. Annual net accumulation of C and N by epiphytic bryophytes was estimated at 37–64 g C/m²/yr and 0.8–1.3 g N/m²/yr, respectively. Previous research at this site indicated that epiphytic bryophytes retain inorganic N from atmospheric deposition to the canopy. Therefore, they play a major role in transforming N from mobile to highly recalcitrant forms in this ecosystem.     

The Low Fall as a Surrogate Marker of Frailty Predicts Long-Term Mortality in Older Trauma Patients

Background

Frailty is associated with adverse outcomes including disability, mortality and risk of falls. Trauma registries capture a broad range of injuries. However, frail patients who fall comprise a large proportion of the injuries occurring in ageing populations and are likely to have different outcomes compared to non-frail injured patients. The effect of frail fallers on mortality is under-explored but potentially significant. Currently, many trauma registries define low falls as less than three metres, a height that is likely to include non-frailty falls. We hypothesized that the low fall from less than 0.5 metres, including same-level falls, is a surrogate marker of frailty and predicts long-term mortality in older trauma patients.

Methods

Using data from the Singapore National Trauma Registry, 2011–2013, matched till September 2014 to the death registry, we analysed adults aged over 45 admitted via the emergency department in public hospitals sustaining blunt injuries with an injury severity score (ISS) of 9 or more, excluding isolated hip fractures from same-level falls in the over 65. Patients injured by a low fall were compared to patients injured by high fall and other blunt mechanisms. Logistic regression was used to analyze 12-month mortality, controlling for mechanism of injury, ISS, revised trauma score (RTS), co-morbidities, gender, age and age-gender interaction. Different low fall height definitions, adjusting for injury regions, and analyzing the entire adult cohort were used in sensitivity analyses and did not change our findings.

Results

Of the 8111 adults in our cohort, patients who suffered low falls were more likely to die of causes unrelated to their injuries (p<0.001), compared to other blunt trauma and higher fall heights. They were at higher risk of 12-month mortality (OR 1.75, 95% CI 1.18–2.58, p = 0.005), independent of ISS, RTS, age, gender, age-gender interaction and co-morbidities. Falls that were higher than 0.5m did not show this pattern. Males were at higher risk of mortality after low falls. The effect of age on mortality started at age 55 for males, and age 70 for females, and the difference was attributable to the additional mortality in male low-fallers.

Conclusions

The low fall mechanism can optimize prediction of long-term mortality after moderate and severe injury, and may be a surrogate marker of frailty, complementing broader-based studies on aging.     

Imaging the subcellular structure of human coronary atherosclerosis using micro-optical coherence tomography

Progress in understanding, diagnosis, and treatment of coronary artery disease (CAD) has been hindered by our inability to observe cells and extracellular components associated with human coronary atherosclerosis in situ. The current standards for microstructural investigation, histology and electron microscopy are destructive and prone to artifacts. The highest-resolution intracoronary imaging modality, optical coherence tomography (OCT), has a resolution of ~10 μm, which is too coarse for visualizing most cells. Here we report a new form of OCT, termed micro-optical coherence tomography (μOCT), whose resolution is improved by an order of magnitude. We show that μOCT images of cadaver coronary arteries provide clear pictures of cellular and subcellular features associated with atherogenesis, thrombosis and responses to interventional therapy. These results suggest that μOCT can complement existing diagnostic techniques for investigating atherosclerotic specimens, and that μOCT may eventually become a useful tool for cellular and subcellular characterization of the human coronary wall in vivo.     

Animals as Sentinels of Human Environmental Health Hazards: An Evidence-Based Analysis

Despite recognition that animals could be serving as sentinels for environmental risks to human health, there are no evidence-based guidelines for the use of animal sentinel data in human health decision making. We performed a systematic review of the animal sentinel literature to assess the evidence linking such events to human health. A search of MEDLINE identified peer-reviewed original studies of animals as sentinels for either chemical or biological environmental hazards. A limited search of the CAB and AGRICOLA databases was also performed. We classified a random sample of 100 studies from the MEDLINE search according to species, hazard, and health outcome examined; study methods; and linkages to human health. Animal sentinel studies were difficult to locate in MEDLINE because of a lack of adequate key words for this concept. We found significant limitations in the study methods used to investigate animal sentinel events. Clear linkages to human health were frequently absent. Studies of sentinel events in animal populations hold potential for the recognition and control of human environmental health hazards, yet a number of barriers exist to using such data for evidence-based human health decisions. There is a need for greater data sharing and cooperative research between human and animal health professionals regarding environmental hazards and health outcomes in animal and human populations.