Early Migration Research Articles

Detection of H5N1 High Pathogenicity Avian Influenza Viruses in Four Raptors and Two Geese in Japan in the Fall of 2022.

In the fall of 2022, high pathogenicity avian influenza viruses (HPAIVs) were detected from raptors and geese in Japan, a month earlier than in past years, indicating a shift in detection patterns. In this study, we conducted a phylogenetic analysis on H5N1 HPAIVs detected from six wild birds during the 2022/2023 season to determine their genetic origins. Our findings revealed that these HPAIVs belong to the G2 group within clade 2.3.4.4b, with all isolates classified into three subgroups: G2b, G2d, and G2c. The genetic background of the G2b virus (a peregrine falcon-derived strain) and G2d viruses (two raptors and two geese-derived strains) were the same as those detected in Japan in the 2021/2022 season. Since no HPAI cases were reported in Japan during the summer of 2022, it is probable that migratory birds reintroduced the G2b and G2d viruses. Conversely, the G2c virus (a raptor-derived strain) was first recognized in Japan in the fall of 2022. This strain might share a common ancestor with HPAIVs from Asia and West Siberia observed in the 2021/2022 season. The early migration of waterfowl to Japan in the fall of 2022 could have facilitated the early invasion of HPAIVs.

The impact of background water flow on the early migration of a CO2 plume in a tilted aquifer during the post-injection period

The impact of background water flow on the early migration of a CO2 plume in a tilted aquifer during the post-injection period

Migration timing and tributary use of spawning flannelmouth sucker (Catostomus latipinnis).

Spawning phenology and associated migrations of fishes are often regulated by factors such as temperature and stream discharge, but flow regulation of mainstem rivers coupled with climate change might disrupt these cues and affect fitness. Flannelmouth sucker (Catostomus latipinnis) persisting in heavily modified river networks are known to spawn in tributaries that might provide better spawning habitat than neighboring mainstem rivers subject to habitat degradation (e.g., embedded sediments, altered thermal regimes, and disconnected floodplains). PIT tag data and radio telemetry were used to quantify the timing and duration of flannelmouth sucker tributary spawning migrations in relation to environmental cues in McElmo Creek, a tributary of the San Juan River in the American Southwest. We also tested the extent of the tributary migration and assessed mainstem movements prior to and after tributary migrations. Additionally, multiyear data sets of PIT detections from other tributaries in the Colorado River basin were used to quantify interannual and cross-site variation in the timing of flannelmouth sucker spawning migrations in relation to environmental cues. The arrival and residence times of fish spawning in McElmo Creek varied among years, with earlier migration and a 3-week increase in residence time in relatively wet years compared to drier years. Classification tree analysis suggested a combination of discharge- and temperature-determined arrival timing. Of fish PIT tagged in the fall, 56% tagged within 10 km of McElmo Creek spawned in the tributary the following spring, as did 60% of radio-tagged fish, with a decline in its use corresponding to increased distance of tagging location. A broader analysis of four tributaries in the Colorado River basin, including McElmo Creek, found photoperiod and temperature of tributary and mainstem rivers were the most important variables in determining migration timing, but tributary and mainstem discharge also aided in classification success. The largest tributary, the Little Colorado River, had more residential fish or fish that stayed for longer periods (median = 30 days), whereas McElmo Creek fish stayed an average of just 10 days in 2022. Our results generally suggest that higher discharge, across years or across sites, results in extended use of tributaries by flannelmouth suckers. Conservation actions that limit water extraction and maintain natural flow regimes in tributaries, while maintaining open connection with mainstem rivers, may benefit migratory species, including flannelmouth suckers.

Surgical approach had minor association with femoral stem migration in total hip arthroplasty: radiostereometric analysis of 61 patients after 5-year follow-up.

Total hip arthroplasty (THA) is usually performed using 1 of 3 surgical approaches: direct lateral (DLA), posterior (PA), or anterior (AA). AA is different from DLA and PA owing to limited intraoperative visibility of the femoral canal. This could affect stem positioning and therefore migration. We aimed to perform an exploratory radiostereometric analysis (RSA) study with 3 groups for surgical approach assessing stem migration up to 5 years postoperatively. 61 patients with unilateral osteoarthritis of the hip were included. 21 patients were allocated to the DLA, 20 to the PA, and 20 to the AA group. All patients received an uncemented, collarless, double-tapered, fully hydroxyapatite-coated Profemur Gladiator stem. Migration was measured with model-based RSA. Baseline RSA was on day 1 postoperatively. The follow-ups were at day 8, at 5 weeks, and at 3, 6, 12, 24, and 60 months after surgery. Generalized linear mixed models were used to analyze maximum total point motion (MTPM) migrations. Group mean differences in MTPM were 0.4 mm (95% confidence interval [CI] -1.5 to 2.4) for DLA vs. PA, 1.1 mm (CI -1.0 to 3.3) for AA vs. DLA, and 1.6 mm (CI -0.8 to 3.9) for AA vs. PA, when adjusted for sex and age as covariates. 2 stems in the AA group had excessive early migration. For all stems the migrations occurred mainly within 5-week follow-up and then stabilized. At 5-year follow-up, there were no statistically significant differences in stem migration associated with the 3 surgical approaches used in this study.

Radial distribution of distant trans-Neptunian objects points to Sun’s formation in a stellar cluster

The Scattered Disk Objects (SDOs) are a population of trans-Neptunian bodies with semimajor axes 50<a≲1000 au and perihelion distances q≳30 au. The detached SDOs with orbits beyond the reach of Neptune (roughly q>35 au) are of special interest here as an important constraint on the early evolution of the outer Solar System. The semimajor axis profile of detached SDOs at 50–500 au, as characterized from the Dark Energy Survey (DES), is radially extended, but previous dynamical models of Neptune’s early migration produce a relatively compact profile. This problem is most likely related to Sun’s birth environment in a stellar cluster. We perform new dynamical simulations that account for cluster effects and show that the orbital distribution of SDOs can be explained if a particularly close stellar encounter occurred early on (e.g., M dwarf with the mass ≃0.2M⊙ approaching the Sun at ≃200 au). For such an encounter to happen with a reasonably high probability the Sun must have formed in a stellar cluster with ηT≳104 Myr pc−3, where η is the stellar number density and T is the Sun’s residence time in the cluster.

Genetic monitoring of steelhead in the Klickitat River to estimate productivity, straying, and migration timing

AbstractObjectiveSalmonids with a complex life history variation present challenges for conservation management, but genetic approaches alongside fisheries monitoring can address questions regarding the viability of the natural populations.MethodsWe genotyped adult (n = 3108) and juvenile (n = 2624) samples of steelhead Oncorhynchus mykiss that were collected in the Klickitat River, Washington, USA at traps in the lower drainage to examine tributary level productivity, straying from outside sources, and variation in adult migration timing.ResultGenetic assignment of steelhead from this system indicated that the majority were produced within or near tributaries of the middle Klickitat River (juvenile mean = 72.8%; adult mean = 87.3%). Analyses with parentage‐based tagging identified that most hatchery‐origin adults were assigned to the Skamania Hatchery (80.8%), as expected, since this has been the release stock for decades within the Klickitat River drainage. Hatchery‐origin adults were also identified from programs operating outside the Klickitat River, which were primarily strays from Snake River hatcheries. Most natural‐origin steelhead were assigned to the Klickitat River, but there were also natural‐origin fish identified as strays from other regions of the Columbia River (22.3% of natural returns). We also examined genes known to be associated with migration timing in adult steelhead observed at the trap and observed a strong relationship between migration date and alleles for early and late migration, but individual outliers were detected across seasons.ConclusionOur results indicate that genetic variation of steelhead in the Klickitat River has been influenced by hatchery programs as well as natural‐origin straying from other subbasins, but genetic diversity remains high throughout the subbasin, and both early and late migration alleles are maintained. The genetic diversity present in Klickitat River steelhead may enable this Endangered Species Act listed (threatened) species to better adapt to stochastic environmental conditions compared to less diverse populations.

Migration Characteristics of a Proximally Coated Collarless Femoral Stem: A Prospective 2-Year Radiostereometric Analysis Study.

Collared femoral stems have been considered to reduce the risk of early subsidence over collarless stems. However, with advances in material technology, new surface treatments have been introduced into cementless stem design to enhance primary fixation and long-term stability. This study aims to analyze the early migration behaviors of a proximally coated collarless femoral stem and cementless acetabular component and compare the outcomes with commercially available cementless stems and acetabular cups. A total of 24 patients (25 hips) undergoing total hip arthroplasty were recruited and followed up for 2years. All patients received a Masterloc femoral stem (Medacta International SA, Castel San Pietro, Switzerland) and an Mpact acetabular component (Medacta International SA, Castel San Pietro, Switzerland) with tantalum beads embedded during the operation. Radiographs for radiostereometric analysis were taken immediately postsurgery, 6-months, 1-year, and 2-years postoperatively. The median condition number for this study was 59. The median stem subsidence was-0.08 mm (-2.47 to 0.40) at 2 years. The median cup subsidence was-0.03 mm (-0.38 to 0.57) at 2 years. The migration of the Masterloc stem was less than that of other cementless collarless, as well as collared stems, as reported in literature. This study has demonstrated the high stability and fixation provided with the use of a collarless cementless stem. The subsidence seen in both this cementless femoral stem and acetabular cup at 2 years postoperative was below the range reported in literature for cementless collarless and collared stems.

Subsidence analysis of a cementless short stem THA using EBRA-FCA - A seven-year prospective multicentre study

BackgroundMetaphyseal fixation of short stem THA allows for minimally invasive surgery, less bone removal, improved bone load transfer and reduced stress shielding. Short stems facilitate the anatomic restoration i.a. of leg length, femoroacetabular offset, and center of rotation. However, metaphyseal fixation might cause impaired primary and/or secondary stability resulting in an inherent tendency for early axial migration and aseptic loosening eventually. The objective of this study was to investigate the long-term outcome and migration pattern of a calcar-guided short stem. MethodsIn a prospective multicenter study, 213 patients (224 THAs) were enrolled. Patients were followed for up to 84 months postoperatively. Clinical outcome was assessed using the Harris Hip Score and the VAS for pain and satisfaction. Standardized and calibrated radiographs were screened i.a. for stress shielding and loosening. Einzel-Bild-Roentgen-Analyse – femoral component analysis (EBRA-FCA) was used to detect longitudinal subsidence. ResultsAt 7 year follow-up, n = 139/224 cases were available for analysis. All clinical parameters improved significantly (p < 0.001) and improvement persisted. There were no radiographic changes indicating stress shielding. EBRA-FCA revealed a mean subsidence of −1.44 mm followed by a stabilization. Weight >80 kg (p = 0.115), BMI <30 kg/m2 (p = 0.282), male gender (p = 0.246), and age <65 years (p = 0.304) seemed to be associated with a higher risk for migration. The cumulative revision rate was 2.23%. Revisions due to stem migration (0.89%) occurred early (mean time between index surgery and revision: 3.3 months). ConclusionsIf at all, there appears to be a pronounced initial subsidence, which stabilizes thereafter. Stem migration was rarely a compelling reason for failure or revision. Demographics do not seem to have a significant effect on migration pattern. The absence of radioluce lines, resorption or hypertrophy of the proximal femora support the hypothesis of a reduced stress shielding for metaphyseal anchoring short stems.

Early diagenetic REE migration from Fe-Mn nodules to fish teeth in deep sea sediments

In deep sea sediments, rare earth elements and yttrium (REYs) are predominantly carried by bioapatite and Fe-Mn (oxyhydr)oxides. According to recent studies, REYs can migrate into bioapatite after the dissolution of Fe-Mn (oxyhydr)oxides. However, the REY migration mechanism from Fe-Mn (oxyhydr)oxides to bioapatite are still unclear. Here, we integrated in situ trace element and Nd isotope analyses to elucidate the geochemical characteristics of fish tooth-bearing Fe-Mn nodules from the Northwest Pacific Ocean. Our Fe-Mn nodule samples can be classified into different morphological and geochemical types of the different periods in early diagenesis: (I) completely overgrown around bioapatite; II) overgrown around half of the bioapatite. Type I nodules grow around a bioapatite core, which has high LaN/SmN (0.41–0.50, avg. 0.46) and LaN/YbN (0.49–0.90, avg. 0.62). The ΣREY content is non-uniform in the two bioapatite types (WP-01 & WP-02) in Type I nodules, i.e., 475–2150 ppm and 272–431 ppm, respectively. The REY results show that the bioapatite is mainly adsorbed REY in early diagenesis. Type II nodules were covered both inside and at the tip of the tooth. The LaN/SmN (0.34–0.38, avg. 0.36) and LaN/YbN (0.26–0.61, avg. 0.37) ratios of the bioapatite samples are relatively low. Meanwhile, the ΣREY content is very uneven (229–3521 ppm). The REY data show that the bioapatite is mainly substituted during strong early diagenesis. The intercrystalline pores in some authigenic apatite may have closed upon recrystallization, causing REY redistribution and fractionation. The Y/Ho vs. ΣREE/Th plot shows a higher REY proportion from pore water in type II nodules than in type I ones. The widespread distribution of high Mn content and the gradual decrease of REY content from the nodule rim to core reflect the transport of REY from dissolved Fe-Mn (oxyhydr)oxides to bioapatite during early diagenesis under suboxic conditions. From type I to type II nodules, the mean εNd value of bioapatite increases from −6.69 to −5.56. The comparison of εNd values between REY-rich mud and bioapatite indicate that the REYs were derived from the bottom water and pore water in deep sea sediments. Our findings comprehensively document the transport and enrichment mechanisms of REY in early diagenetic processes from Fe-Mn (oxyhydr)oxides to bioapatite, which we argued to be relatively localized.

Role of precession on the transition seasons of the Asian monsoon

While there have been many paleoclimate studies on the precessional control of climate, typically only the orbital phase where perihelion occurs close to the solstices has received attention. Here, we explore how precession affects the seasonal evolution of the Asian summer monsoon in the transitional seasons of boreal spring and autumn. With perihelion occurring in boreal spring, the Hadley circulation weakens over the northern Indian Ocean, linked to precession-enhanced sensible heating over the Tibetan Plateau. There is an early northward migration of the midlatitude westerly jet stream, and the advancement of the pre-monsoon along the Asian–Australian land bridge. The pre-monsoon response to precession may have had a major role in the early part of the last deglaciation, when perihelion last occurred during boreal spring. A weak continental summer monsoon and autumn aphelion during the early part of the last deglaciation led to a weak Pacific high over the east of coastal East Asia, allowing for a vigorous oceanic western North Pacific monsoon in the late summer. Additionally, the seasonal expansion of oceanic monsoon trough could shed light on the quasi-stationarity of the oceanic monsoon during a precessional cycle.

Presence of intra-aneurysmal thrombi with delayed coil migration after embolization of an aneurysmal subarachnoid hemorrhage: illustrative case.

Coil migration is a rare, but notable complication of endovascular treatment. Risk factors include communicating segment aneurysms, aneurysmal shape, and technical factors. Although cerebral blood flow obstruction caused by early coil migration requires urgent coil removal, delayed coil migration is often asymptomatic, making it difficult to determine a treatment strategy. A 47-year-old woman was referred to the institute with acute-onset headache. She was diagnosed with subarachnoid hemorrhage due to rupture of the right internal carotid artery-posterior communicating artery aneurysm and underwent endovascular coil embolization. Following the procedure, the patient showed no obvious complications; however, 14 days later, images showed coil migration to the distal side, leading to surgical removal. Right frontotemporal craniotomy was performed, and the remaining coil was removed. The aneurysm was clipped again, and blood flow was confirmed. The patient was discharged 12 days after the craniotomy with transient oculomotor nerve palsy. At the 15-month follow-up, there was no aneurysm recurrence and the oculomotor nerve palsy showed improvement. Retrieval of the migrated coil by craniotomy is an effective remedial measure; however, intraoperative complications are common. Early detection, established protocols, and prompt treatment decisions are important for preventing undesirable outcomes.

Pulmonary Expression of Interleukin-17 Contributes to Neutrophil Infiltration into the Lungs during Pneumonic Plague.

Inhalation of respiratory droplets infected with Yersinia pestis results in a rapidly progressing and lethal necrotic pneumonia called primary pneumonic plague. Disease manifests as biphasic, with an initial preinflammatory phase with rapid bacterial replication in the lungs absent readily detectable host immune responses. This is followed by the onset of a proinflammatory phase that sees the dramatic upregulation of proinflammatory cytokines and extensive neutrophil accumulation in the lungs. The plasminogen activator protease (Pla) is an essential virulence factor that is responsible for survival of Y. pestis in the lungs. Our lab recently showed that Pla functions as an adhesin that promotes binding to alveolar macrophages to facilitate translocation of effector proteins called Yops into the cytosol of target host cells via a type 3 secretion system (T3SS). Loss of Pla-mediated adherence disrupted the preinflammatory phase of disease and resulted in early neutrophil migration to the lungs. While it is established that Yersinia broadly suppresses host innate immune responses, it is not clear precisely which signals need to be inhibited to establish a preinflammatory stage of infection. Here, we show that early Pla-mediated suppression of Interleukin-17 (IL-17) expression in alveolar macrophages and pulmonary neutrophils limits neutrophil migration to the lungs and aids in establishing a preinflammatory phase of disease. In addition, IL-17 ultimately contributes to neutrophil migration to the airways that defines the later proinflammatory phase of infection. These results suggest that the pattern of IL-17 expression contributes to the progression of primary pneumonic plague.

Ancient mitochondrial genome depicts sheep maternal dispersal and migration in Eastern Asia

Sheep have been one of the most important groups of animals since ancient times. However, the knowledge of their migration routes and genetic relationships is still poorly understood. To investigate sheep maternal migration histories alongside Eurasian communications routes, in this study, we obtain mitochondrial genomes (mitogenomes) from 17 sheep remains in 6 Chinese sites and 1 Uzbekistan site dated 4429–3100 years before present (BP). By obtaining the mitogenomes from the sheep (4429–3556 BP) found in the Tongtian Cave site in Xinjiang, Altai region of northwest China, our results support the emergence of haplogroup C sheep in Xinjiang as early as 4429–3556 BP. The combined phylogenetic analyses with extant ancient and modern sheep mitogenomes suggest that the Uzbekistan-Altai region may have been a migration hub for early sheep in eastern Asia. At least two migration events have taken place for sheep crossing Eurasia to China, one passing by Uzbekistan and Northwest China to the middle and lower reaches of the Yellow River at approximately 4000 BP and another following the Altai region to middle Inner Mongolia from 4429 BP to 2500 BP. Overall, this study provides further evidence for early sheep utilization and migration patterns in Eastern Asia.

Does early-life migration experience determine health and health-risk behavior in later life? Evidence from elderly returns migrants in Kerala, India

Becoming elderly is an intrinsic part of life, and the burden of disease increases with age. However, the early life migration experience and occupational hazards at the destination can lead to serious health problems later in life. This study aims to understand the association between early life migration and the health and risky behavior of elderly return migrants using data from the Kerala Migration Survey in 2018. The results of bivariate and multivariate analyses show that the majority of migrants return due to retirement and ill health at the average age of 51 and suffer from poor health and multiple diseases. More than half (55%) of elderly returnees reported poor health, and among them, 70% have at least one chronic disease. The early life migration experience and injuries at the destination are the main determinants of poor self-rated health and chronic disease. Furthermore, elderly return migrants have high-risk health behaviours such as smoking and alcohol consumption, as well as less access to health schemes. Despite some shortcomings, this study identifies the most vulnerable groups among the elderly and their health characteristics. This will help to promote healthy aging in Kerala, India, or areas with increasing numbers of elderly and return migrants around the world.

Evolutionary analysis of JC polyomavirus in Misiones’ population yields insight into the population dynamics of the early human dispersal in the Americas

BackgroundJC polyomavirus (JCV) has an ethno-geographical distribution across human populations. ObjectiveStudy the origins of the population of Misiones (Argentina) by using JCV as genetic marker. MethodsViral detection and characterization was conducted by PCR amplification and evolutionary analysis of the intergenic region sequences. Results22 out of 121 samples were positive for JCV, including 5 viral lineages: MY (n = 8), Eu-a (n = 7), B1-c (n = 4), B1-b (n = 2) and Af2 (n = 1). MY sequences clustered within a branch of Native American origin that diverged from its Asian counterpart about 21,914 years ago (HPD 95% interval 15,383–30,177), followed by a sustained demographic expansion around 5000 years ago. ConclusionsJCV in Misiones reflects the multiethnic origin of the current population, with an important Amerindian contribution. Analysis of the MY viral lineage shows a pattern consistent with the arrival of early human migrations to the Americas and a population expansion by the pre-Columbian native societies.

Prehistoric population expansion in Central Asia promoted by the Altai Holocene Climatic Optimum

How climate change in the middle to late Holocene has influenced the early human migrations in Central Asian Steppe remains poorly understood. To address this issue, we reconstructed a multiproxy-based Holocene climate history from the sediments of Kanas Lake and neighboring Tiewaike Lake in the southern Altai Mountains. The results show an exceptionally warm climate during ~6.5–3.6 kyr is indicated by the silicon isotope composition of diatom silica (δ30Sidiatom) and the biogenic silica (BSi) content. During 4.7-4.3 kyr, a peak in δ30Sidiatom reflects enhanced lake thermal stratification and periodic nutrient limitation as indicated by concomitant decreasing BSi content. Our geochemical results indicate a significantly warm and wet climate in the Altai Mountain region during 6.5–3.6 kyr, corresponding to the Altai Holocene Climatic Optimum (AHCO), which is critical for promoting prehistoric human population expansion and intensified cultural exchanges across the Central Asian steppe during the Bronze Age.

Using qPCR of environmental DNA (eDNA) to estimate the biomass of juvenile Pacific salmon (Oncorhynchus spp.)

AbstractDuring the outmigration of Pacific Salmon, the early marine phase is a critical period when high mortality can occur. Traditional sampling and monitoring of juvenile salmon migration can be limited by logistically intensive gear requirements, accessibility, and cost. Improved understanding of the early marine phase, for example, migration duration and habitat use, requires innovative techniques that can improve the spatial and temporal coverage of monitoring. Environmental DNA (eDNA) is genetic fragments present in the environment that can be used as a proxy for organism presence and can be effectively and efficiently collected through water samples. Estimating fish abundance or biomass from eDNA concentration data would provide a valuable fisheries tool but remains challenging to calibrate. To quantify the relationship between eDNA abundance and fish biomass, we used a controlled mesocosm experiment, in which eDNA samples were collected from 15 aquaria (340 L) with varying densities of juvenile Chinook salmon per tank (0, 5, 10, 20, and 30). The concentration of eDNA was obtained by qPCR scaled with fish biomass (ANOVA, p &lt; 0.05). However, we also observed that variability of eDNA concentrations among replicates of the same treatment positively scaled biomass (ANOVA, p &lt; 0.05). Therefore, higher biomasses of fish can yield more challenging data to interpret. This study lays important groundwork for the application of eDNA for monitoring juvenile salmonids yet highlights caveats for the applicability of eDNA as a stand‐alone method to assess biomass in a field setting.

The role of Raptor in lymphocytes differentiation and function.

Raptor, a key component of mTORC1, is required for recruiting substrates to mTORC1 and contributing to its subcellular localization. Raptor has a highly conserved N-terminus domain and seven WD40 repeats, which interact with mTOR and other mTORC1-related proteins. mTORC1 participates in various cellular events and mediates differentiation and metabolism. Directly or indirectly, many factors mediate the differentiation and function of lymphocytes that is essential for immunity. In this review, we summarize the role of Raptor in lymphocytes differentiation and function, whereby Raptor mediates the secretion of cytokines to induce early lymphocyte metabolism, development, proliferation and migration. Additionally, Raptor regulates the function of lymphocytes by regulating their steady-state maintenance and activation.

Evaluation of nutritive condition and reproductive status of migrating gray whales (Eschrichtius robustus) based on analysis of photogrammetric data

Vertical aerial photographs were collected of gray whales migrating along the California Coast between 1994 and 1998 to readdress some published findings on the biology and life history of this population based on examination of specimens. For each whale, an attempt was made to measure standard total length, the width of the whale at its widest point, the distance from the tip of the rostrum to the widest point, and the width of the flukes. For southbound gray whales, early migrants were longer on average and more likely to be parturient than those migrating later. Near-term pregnant females were wider relative to their length than other southbound gray whales. This difference was easily detected by visual inspection of the images and through statistical evaluation of length and width data. There was 100% agreement between identification of parturient females based on linear regression analysis of length and width and discriminate analysis of all measurements. Based on the proportion of parturient females to those with calves during sampling of southbound whales, the median calving date was estimated to be 13 January. Southbound calves averaged 4.6m in length; those photographed northbound in late April, at an age of about three months, averaged 7.1m. Average length for yearlings, based on combined southbound and northbound data, was 8.5m. Residuals from a regression of width on length were compared, and significant changes in the relationship were detected which were consistent with changes in nutritive condition or fatness described from examination of whales taken along the California Coast between 1959 and 1969 (Rice and Wolman, 1971). Parturient females were the widest relative to their length and northbound cows with calves were the narrowest in the sample. The relationship between length and width for migrating gray whales that were not parturient or associated with a calf, showed that southbound gray whales were significantly wider than northbound whales photographed approximately 60 days later. These results indicate that the predictable but relatively small changes in condition or fatness of gray whales associated with fasting during their winter migration can be reliably detected in measurements from vertical aerial photographs.

Early and late-onset cell migration from peripheral corneal endothelium.

In this study we describe peripheral corneal endothelial cell migration in vitro in the absence and presence of a ROCK-inhibitor. For this study, 21 corneal endothelial graft rims, with attached trabecular meshwork (TM), were prepared from Descemet membrane-endothelial cell sheets by 6.5 mm trepanation. For the initial proof-of-concept, 7 outer graft rims were cultured in a thermo-reversible hydrogel matrix for up to 47 days. To assess the effect of a ROCK-inhibitor, 14 paired outer rims were cultured either with or without ROCK-inhibitor for up to 46 days. At the end of culture, tissue was retrieved from the hydrogel matrix and examined for cell viability and expression of different endothelial cell markers (ZO-1, Na+/K+-ATPase, NCAM, glypican, and vimentin). All cultured rims remained viable and displayed either single regions (n = 5/21) or collective areas (n = 16/21) of cell migration, regardless of the presence or absence of ROCK-inhibition. Migration started after 4±2 days and continued for at least 29 days. The presence of ROCK-inhibitor seemed to contribute to a more regular cell morphology of migrating cells. In addition, 7 outer rims demonstrated a phenotypically distinct late-onset but fast-growing cell population emerging from the area close to the limbus. These cells emerged after 3 weeks of culture and appeared less differentiated compared to other areas of migration. Immunostaining showed that migrated cells maintained the expression patterns of endothelial cell markers. In conclusion, we observed 2 morphologically distinct migrating cell populations with the first type being triggered by a broken physical barrier, which disrupted contact inhibition and the second, late-onset type showing a higher proliferative capacity though appearing less differentiated. This cell subpopulation appeared to be mediated by stimuli other than loss of contact inhibition and ROCK-inhibitor presence. Further exploration of the differences between these cell types may assist in optimizing regenerative treatment options for endothelial diseases.