Behavioral Responses to Changes in Hydrostatic Pressure and Light During Larval Development of the Lobster Homarus americanus

1975 ◽  
Vol 32 (2) ◽  
pp. 271-281 ◽  
Author(s):  
G. P. Ennis
Keyword(s):  
Hydrostatic Pressure ◽  
Stage Iv ◽  
Homarus Americanus ◽  
Stage I ◽  
Upward Movement ◽  
Larval Life ◽  
Downward Movement ◽  
Vertical Movements ◽  
Instantaneous Pressure ◽  
Pressure Changes

Larvae of the lobster Homarus americanus hatched and reared under laboratory conditions in shallow water responded to changes in hydrostatic pressure in a depth-regulatory manner. Responsiveness to instantaneous pressure increments ranging from 1 to 20 psi increased linearly up to 10 psi but varied little at higher pressures. Sensitivity to pressure changes was retained throughout larval life up to and including stage IV (megalopa) but stage III and IV larvae were much less responsive than stage I and II. Stage V (1st juvenile) lobsters were nonresponsive to pressure changes. Larvae were much less responsive (in terms of vertical movements) to changes in light intensity than to changes in pressure, and there were no clear, sustained phototactic or photopathic responses in the vertical plane.In the sea, stage I, II, and III larvae showed limited downward movement when released at the surface and generally upward movement when released below the surface. Newly-molted stage IV larvae generally remained at the surface when released there and swam to the surface when released at the bottom; those 14–15 days after molting also tended to remain at the surface but when released at the bottom they generally remained there and found shelters. Newly-molted stage V juveniles generally remained where they were released, both at the surface and at the bottom, but those 13–15 days after molting when released at the surface generally swam to the bottom and found shelters, and when released at the bottom, remained there.

Behavioral Responses to Changes in Hydrostatic Pressure and Light During Larval Development of the Lobster Homarus gammarus

1973 ◽  
Vol 30 (9) ◽  
pp. 1349-1360 ◽  
Author(s):  
G. P. Ennis
Keyword(s):  
Hydrostatic Pressure ◽  
Light Intensity ◽  
Average Rate ◽  
Stage Iv ◽  
Initial Response ◽  
Consistent Difference ◽  
Upward Movement ◽  
Downward Movement ◽  
Homarus Gammarus ◽  
Pressure Changes

Larvae of the lobster Homarus gammarus hatched and reared under laboratory conditions in shallow water responded to changes in hydrostatic pressure in a depth-regulatory manner. Responsiveness to instantaneous pressure increments ranging from 1 to 20 psi increased linearly and there was no threshold of sensitivity within the range tested. Pressure sensitivity was retained throughout larval life up to and including stage IV (megalopa) but responsiveness weakened with age at least up to stage III. Stage IV larvae were highly responsive to pressure changes but stage V (1st juvenile) lobsters were nonresponsive. Older larvae accommodated to sustained pressure more rapidly than younger larvae and larvae quickly became nonresponsive to repeated pressure changes. After being held at high pressure, larvae responded to slight pressure decreases by downward movement even though still held at pressures to which they would initially respond by vigorous upward movement. Larvae were more responsive to pressure in overhead light than in darkness but light intensity had no apparent effect on the initial response nor on the rate of accommodation to sustained pressure, but in darkness the initial response was slower. Responsiveness to sudden changes in light intensity was much less marked than to pressure changes and it also weakened with age. In the sea older larvae showed a stronger tendency for downward movement when released at the surface and a decreasing tendency for upward movement when released at depths of 25 ft (7.61 m) or more. The average rate of upward movement decreased over a 5-min period and there was no consistent difference in this rate or in the rate at which it decreased when larvae were released at different depths. The average rate of upward movement tended to decrease with age.

La répartition horizontale et verticale des larves de homard (Homarus americanus) autour des îles de la Madeleine, golfe du Saint-Laurent

1986 ◽  
Vol 43 (11) ◽  
pp. 2164-2176 ◽  
Author(s):  
Christiane Hudon ◽  
Pierre Fradette ◽  
Pierre Legendre
Keyword(s):  
Vertical Distribution ◽  
General Pattern ◽  
Stage Iv ◽  
Homarus Americanus ◽  
Stage I ◽  
Larval Abundance ◽  
Larval Stages ◽  
Vertical Distributions ◽  
Horizontal And Vertical Distributions ◽  
La Madeleine

Thirty-nine stations localized around the eastern tip of the Îles de la Madeleine, in two lagoons, and in the baie de Plaisance were sampled using plankton net tows during the summers of 1978, 1980, and 1981. The horizontal and vertical distributions of each of the four larval stages of Homarus americanus were assessed from sets of surface tows using simple neuston and meter nets (1978 and 1980) as well as a three-compartment plankton net (1981). Most of the stage I larval production takes place in the northeast and southeast regions. However, the abundance of stage IV larvae is low in the southeast and almost nil in the northeast. By contrast, the baie de Plaisance harbors very few stage I larvae, but a very high proportion of stage III and IV larvae. The periods of first appearance and maximum abundance are also out of phase for the three regions, occurring in the northeast before the southeast and the baie de Plaisance. These results suggest that the general pattern of abundance of larvae is driven by the current regime, flushing the larvae around the Pointe de l'Est and concentrating them in the baie de Plaisance following a gyre. On a smaller scale, 12 stations arranged in a 3 × 4 grid in the baie de Plaisance were sampled for 12 wk in the summer of 1980. The first three larval stages show a strongly aggregated distribution and are most frequent at the mouth of the bay. Conversely, stage IV larvae are found more frequently in the shore stations and inside the bay. There is a significant correlation between stage IV larval abundance and the distance to rocky bottoms favorable to benthic life. The vertical distribution of larvae at two stations (1981) shows that only the stage I larvae have a vertical distribution related to light intensity, being found in highest abundance in the surface layer (0–0.8 m) at dusk and dawn. Stage I larvae were uniformly distributed between 0 and 1.6 m during the day and down to 2.4 m at night. Stage II, III, and IV larvae were always found near the surface.

scholarly journals Gastric Cancer Treatments and Survival Trends in the United States

2020 ◽  
Vol 28 (1) ◽  
pp. 138-151
Author(s):  
Kelly A. Stahl ◽  
Elizabeth J. Olecki ◽  
Matthew E. Dixon ◽  
June S. Peng ◽  
Madeline B. Torres ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Overall Survival ◽  
Stage Iv ◽  
The United States ◽  
Current Treatment ◽  
Stage I ◽  
Stage Ii ◽  
Chi Square ◽  
Specific Guideline ◽  
Kaplan Meier

Gastric cancer is the third most common cause of cancer deaths worldwide. Despite evidence-based recommendation for treatment, the current treatment patterns for all stages of gastric cancer remain largely unexplored. This study investigates trends in the treatments and survival of gastric cancer. The National Cancer Database was used to identify gastric adenocarcinoma patients from 2004–2016. Chi-square tests were used to examine subgroup differences between disease stages: Stage I, II/III and IV. Multivariate analyses identified factors associated with the receipt of guideline concordant care. The Kaplan–Meier method was used to assess three-year overall survival. The final cohort included 108,150 patients: 23,584 Stage I, 40,216 Stage II/III, and 44,350 Stage IV. Stage specific guideline concordant care was received in only 73% of patients with Stage I disease and 51% of patients with Stage II/III disease. Patients who received guideline consistent care had significantly improved survival compared to those who did not. Overall, we found only moderate improvement in guideline adherence and three-year overall survival during the 13-year study time period. This study showed underutilization of stage specific guideline concordant care for stage I and II/III disease.

scholarly journals Serum Biomarker Signature-Based Liquid Biopsy for Diagnosis of Early-Stage Pancreatic Cancer

2018 ◽  
Vol 36 (28) ◽  
pp. 2887-2894 ◽  
Author(s):  
Linda D. Mellby ◽  
Andreas P. Nyberg ◽  
Julia S. Johansen ◽  
Christer Wingren ◽  
Børge G. Nordestgaard ◽  
...  
Keyword(s):  
Case Control Study ◽  
Early Stage ◽  
Stage Iv ◽  
The United States ◽  
Case Control ◽  
Stage I ◽  
Serum Biomarker ◽  
Patient Cohort ◽  
Biomarker Signature ◽  
Control Study

Purpose Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis, with a 5-year survival of < 10% because of diffuse symptoms leading to late-stage diagnosis. That survival could increase significantly if localized tumors could be detected early. Therefore, we used multiparametric analysis of blood samples to obtain a novel biomarker signature of early-stage PDAC. The signature was derived from a large patient cohort, including patients with well-defined early-stage (I and II) PDAC. This biomarker signature was validated subsequently in an independent patient cohort. Patients and Methods The biomarker signature was derived from a case-control study, using a Scandinavian cohort, consisting of 16 patients with stage I, 132 patients with stage II, 65 patients with stage III, and 230 patients with stage IV PDAC, and 888 controls. This signature was validated subsequently in an independent case-control cohort in the United States with 15 patients with stage I, 75 patients with stage II, 15 patients with stage III, and 38 patients with stage IV PDAC, and 219 controls. An antibody microarray platform was used to identify the serum biomarker signature associated with early-stage PDAC. Results Using the Scandinavian case-control study, a biomarker signature was created, discriminating samples derived from patients with stage I and II from those from controls with a receiver operating characteristic area under the curve value of 0.96. This signature, consisting of 29 biomarkers, was then validated in an independent case-control study in the United States. The biomarker signature could discriminate patients with stage I and II PDAC from controls in this independent patient cohort with a receiver operating characteristic area under the curve value of 0.96. Conclusion This serum biomarker signature might represent a tenable approach to detecting early-stage, localized PDAC if these findings are supported by a prospective validation study.

Effect of Temperature on the Behavior of Stage IV American Lobster (Homarus americanus) Larvae

2015 ◽  
Vol 34 (2) ◽  
pp. 545-554 ◽  
Author(s):  
Melanie Chiasson ◽  
Gilles Miron ◽  
Dounia Daoud ◽  
Martin D. Mallet
Keyword(s):  
Stage Iv ◽  
Homarus Americanus ◽  
Effect Of Temperature ◽  
American Lobster

Neurogenesis in the thoracic neuromeres of two crustaceans with different types of metamorphic development

1998 ◽  
Vol 201 (17) ◽  
pp. 2465-2479 ◽  
Author(s):  
S Harzsch ◽  
J Miller ◽  
J Benton ◽  
RR Dawirs ◽  
B Beltz
Keyword(s):  
Embryonic Development ◽  
Larval Development ◽  
Neuronal Development ◽  
Temporal Patterns ◽  
Homarus Americanus ◽  
Spider Crab ◽  
Larval Life ◽  
Larval Stages ◽  
Metamorphic Development ◽  
Embryonic And Larval Development

The mode of embryonic and larval development and the ethology of metamorphosis in the spider crab and the American lobster are very different, and we took advantage of this to compare neuronal development in the two species. The goals of this study were to discover whether the differences in the maturation of the neuromuscular system in the pereopods and the metamorphic changes of motor behavior between the two species are reflected at the level of the developing nervous system ('neurometamorphosis'). Furthermore, we wanted to broaden our understanding of the mechanisms that govern neuronal development in arthropods. Proliferation of neuronal stem cells in thoracic neuromeres 4-8 of the lobster Homarus americanus and the crab Hyas araneus was monitored over the course of embryonic and larval development using the in vivo incorporation of bromodeoxyuridine (BrdU). Neuropil structure was visualized using an antibody against Drosophila synapsin. While proliferation of neuronal precursors has ceased when embryogenesis is 80 % complete (E80%) in the lobster thoracic neuromeres, proliferation of neuroblasts in the crab persists throughout embryonic development and into larval life. The divergent temporal patterns of neurogenesis in the two crustacean species can be correlated with differences in larval life style and in the degree of maturation of the thoracic legs during metamorphic development. Several unusual aspects of neurogenesis reported here distinguish these crustaceans from other arthropods. Lobsters apparently lack a postembryonic period of proliferation in the thoracic neuromeres despite the metamorphic remodeling that takes place in the larval stages. In contrast, an increase in mitotic activity towards the end of embryonic development is found in crabs, and neuroblast proliferation persists throughout the process of hatching into the larval stages. In both E20% lobster embryos and mid-embryonic crabs, expression of engrailed was found in a corresponding set of neurons and putative glial cells at the posterior neuromere border, suggesting that these cells have acquired similar specific identities and might, therefore, be homologous. None of the BrdU-labeled neuroblasts (typically 6-8 per hemineuromere over a long period of embryogenesis) was positive for engrailed at this and subsequent stages. Our findings are discussed in relation to the spatial and temporal patterns of neurogenesis in insects.

XMAP230 is required for the assembly and organization of acetylated microtubules and spindles in Xenopus oocytes and eggs

1998 ◽  
Vol 111 (16) ◽  
pp. 2315-2327 ◽  
Author(s):  
B.J. Cha ◽  
B. Error ◽  
D.L. Gard
Keyword(s):  
Late Stage ◽  
Xenopus Oocytes ◽  
Early Stage ◽  
Polyclonal Antibodies ◽  
Stage Iv ◽  
Stage I ◽  
Meiotic Spindle ◽  
Heat Stable ◽  
Early Embryos ◽  
And Function

We used affinity-purified polyclonal antibodies to characterize the distribution and function of XMAP230, a heat-stable microtubule-associated protein isolated from Xenopus eggs, during oogenesis. Immunoblots revealed that XMAP230 was present throughout oogenesis and early development, but was most abundant in late stage oocytes, eggs, and early embryos. Immunofluorescence microscopy revealed that XMAP230 was associated with microtubules in oogonia, post-mitotic stage 0 oocytes, early stage I oocytes, and during stage IV-VI of oogenesis. However, staining of microtubules by anti-XMAP230 was not detectable during late stage I through stage III. In stage VI oocytes, anti-XMAP230 stained a large subset of microtubules that were also stained with monoclonal antibodies specific for acetylated (α)-tubulin. During oocyte maturation, XMAP230 was associated with the transient microtubule array that serves as the precursor of the first meiotic spindle, as well as both first and second meiotic spindles. The extensive array of cytoplasmic microtubules present throughout maturation was not detectably stained by anti-XMAP230. Microinjection of anti-XMAP230 locally disrupted the organization and acetylation of microtubules in stage VI oocytes, and reduced the re-acetylation of microtubules during recovery from cold-induced microtubule disassembly. Subsequent maturation of oocytes injected with anti-XMAP230 resulted in defects in the assembly of the transient microtubules array and first meiotic spindle. These observations suggest that XMAP230 is required for the stabilization and organization of cytoplasmic and spindle microtubules in Xenopus oocytes and eggs.

The impact of the COVID-19 pandemic on stage at diagnosis of breast and colorectal cancers.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 6501-6501
Author(s):  
Jade Zhou ◽  
Shelly Kane ◽  
Celia Ramsey ◽  
Melody Ann Akhondzadeh ◽  
Ananya Banerjee ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Colorectal Cancer ◽  
Cancer Screening ◽  
Late Stage ◽  
Stage Iv ◽  
Stage I ◽  
Screening Programs ◽  
Stage Distribution ◽  
Number Of Patients ◽  
The Impact

6501 Background: Effective cancer screening leads to a substantial increase in the detection of earlier stages of cancer, while decreasing the incidence of later stage cancer diagnoses. Timely screening programs are critical in reducing cancer-related mortality in both breast and colorectal cancer by detecting tumors at an early, curable stage. The COVID-19 pandemic resulted in the postponement or cancellation of many screening procedures, due to both patient fears of exposures within the healthcare system as well as the cancellation of some elective procedures. We sought to identify how the COVID-19 pandemic has impacted the incidence of early and late stage breast and colorectal cancer diagnoses at our institution. Methods: We examined staging for all patients presenting to UCSD at first presentation for a new diagnosis of malignancy or second opinion in 2019 and 2020. Treating clinicians determined the stage at presentation for all patients using an AJCC staging module (8th edition) in the electronic medical record (Epic). We compared stage distribution at presentation in 2019 vs 2020, both for cancers overall and for colorectal and breast cancer, because these cancers are frequently detected by screening. Results: Total numbers of new patient visits for malignancy were similar in 2019 and 2020 (1894 vs 1915 pts), and stage distribution for all cancer patients was similar (stage I 32% in 2019 vs 29% in 2020; stage IV 26% in both 2019 and 2020). For patients with breast cancer, we saw a lower number of patients presenting with stage I disease (64% in 2019 vs 51% in 2020) and a higher number presenting with stage IV (2% vs 6%). Similar findings were seen in colorectal cancer (stage I: 22% vs 16%; stage IV: 6% vs 18%). Conclusions: Since the COVID-19 pandemic, there has been an increase in incidence of late stage presentation of colorectal and breast cancer, corresponding with a decrease in early stage presentation of these cancers at our institution. Cancer screening is integral to cancer prevention and control, specifically in colorectal and breast cancers which are often detected by screening, and the disruption of screening services has had a significant impact on our patients. We plan to continue following these numbers closely, and will present data from the first half of 2021 as it becomes available.

Stage at cancer diagnosis during the COVID-19 pandemic in western Washington state.

2021 ◽  
Vol 39 (28_suppl) ◽  
pp. 145-145
Author(s):  
Catherine R. Fedorenko ◽  
Karma L. Kreizenbeck ◽  
Li Li ◽  
Laura Elizabeth Panattoni ◽  
Veena Shankaran ◽  
...  
Keyword(s):  
Medical Care ◽  
Early Stage ◽  
Stage Iv ◽  
Washington State ◽  
Stage I ◽  
Tumor Type ◽  
Stage At Diagnosis ◽  
Stage Iv Cancer ◽  
Using Data ◽  
The Impact

145 Background: The COVID-19 pandemic disrupted medical care, including routine cancer screening for breast, colorectal, lung and cervical cancers. We aimed to investigate the impact of the pandemic on stage at diagnosis for cancer patients. Methods: Using data from the Washington State SEER records we compared AJCC stage for patients diagnosed with cancer in 2017-2019 to 2020 for two time periods, March to June (initial pandemic months) and July to December (later pandemic months). Patients were included if they were age 18+, diagnosed with a solid tumor, and not diagnosed at autopsy. Results: In the early phase of the pandemic, March – June 2020, there was a shift to cancers being diagnosed at a later stage compared to the same time period in 2017-2019 (Stage III: 13.5% to 14.9%, Stage IV: 16.2% to 19.7%). There was also a decrease in cancer diagnoses for cancers that are often detected through routine screening. As a percentage of all cancer diagnoses, both melanoma (13.2% to 9.8%) and colon cancer diagnoses (7.2% to. 6.7%) decreased during the early pandemic. In the later phase of the pandemic, July to December 2020, the stage at diagnosis showed an indication of returning to pre-pandemic levels with an increase in the proportion of early stage cancers (In situ: 16.6% to 19.3%, Stage I: 38.8% to 41.1%). Stage at diagnosis trends varied by tumor type. For colorectal cancer, the overall number of diagnoses decreased during the initial pandemic months. Stage I diagnoses decreased and Stage IV cancer diagnoses increased in both early and late stages of the pandemic. Conclusions: In Washington State, the COVID-19 pandemic had an impact on stage at diagnosis potentially caused by delays or interruptions in medical care. Additional studies are needed to understand how this shift in stage at diagnosis impacted treatment and outcomes for patients.

scholarly journals Characterization of Seminiferous Epithelium Stages in the Wild Javan Muntjac (Muntiacus muntjak muntjak) Using the Tubular Morphology Method

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Sri Wahyuni ◽  
Gholib Gholib ◽  
I Ketut Mudite Adnyane ◽  
Muhammad Agil ◽  
Hamny Hamny ◽  
...  
Keyword(s):  
Small Ruminants ◽  
Stage Iv ◽  
Testicular Tissue ◽  
Seminiferous Epithelium ◽  
Stage I ◽  
Cell Nuclei ◽  
Diplotene Stage ◽  
In The Wild ◽  
Muntiacus Muntjak ◽  
Tubular Morphology

Stages of the seminiferous epithelium of the testis of the wild Javan muntjac (Muntiacus muntjak muntjak) in hard antler period were characterized based on the tubular morphology method. The number and the relative frequencies of seminiferous epithelium stages and the morphometry of germinal cell nuclei were identified microscopically. We identified eight stages of seminiferous epithelium in testicular tissue of the Javan muntjac and found that the relative frequencies of stages I to VIII were 14.87, 15.12, 17.75, 6.87, 7.37, 12.37, 13, and 12.62%, respectively. The diameter of the nuclei of germinal cells varied in each stage of seminiferous epithelium. Diplotene-stage primary spermatocytes had prominent and large nuclei ~8.97 ± 1.0 μm in stages III and IV. Pachytene primary spermatocytes appeared in most stages, except stage IV, whereas leptotene- and diplotene-stage primary spermatocytes were found in stages I and II, and III and IV, respectively. Round spermatids were observed in stages IV to VIII and in stage I but were absent in stages II and III, while elongated spermatids were observed in all stages except stage I. Our findings show that the stages of seminiferous epithelium in the Javan muntjac are similar to those found in neotropical cervids, small ruminants, and other domestic animals.

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