Why so many mammalian spermatozoa - a clue from marsupials?

1984 ◽  
Vol 221 (1223) ◽  
pp. 221-233 ◽  
Keyword(s):  
Didelphis Virginiana ◽  
High Survival ◽  
High Survival Rate ◽  
Sperm Production ◽  
Australian Family ◽  
Cauda Epididymidis ◽  
Virginia Opossum ◽  
Shed Light ◽  
Mammalian Spermatozoa ◽  
Made In

Mammals generally ejaculate many more spermatozoa than seem to be needed for fertilization. This apparent profligacy has not been explained, but observations made in marsupials may shed light on it. The Virginia opossum, Didelphis virginiana , inseminates only about three million spermatozoa, a very low number. As a corollary, relatively few ( ca . 13 x 10 6 ) are stored in each cauda epididymidis. However, some 5% of the spermatozoa that the opossum ejaculates populate the oviduct about 12 h later when ovulation can be anticipated - a success rate in the female orders of magnitude greater than in eutherian mammals. I t is not certain what determines the unusually efficient transport to and the high survival rate of spermatozoa in the oviduct of Didelphis , but two unusual features suggest themselves as possible contributors. Didelphis (and all other American marsupial) spermatozoa undergo a head-to-head pairing in the epididymis by the acrosomal face; this serves to isolate the acrosome of ejaculated spermatozoa from the female milieu until the pairs separate in the oviduct. Secondly, spermatozoa are housed in special crypts in the isthmus of the oviduct. Australian marsupials, which usually lack such features, store spermatozoa in the epididymis in numbers more close to those in comparably sized eutheriam mammals. Exceptions which store very low sperm numbers there can be seen in one Australian Family, the Dasyuridae. The spermatozoa of dasyurids are not paired, but the species examined possess distinctive sperm storage crypts in the oviducal isthmus similar to those in the opossum. The present findings suggest that where mechanisms exist that could protect the acrosome and, or, the whole spermatozoon in the female tract, a much lower level of sperm production can be maintained without compromising fertility. While the number ejaculated typically by any one species is probably determined ultimately by several interacting factors, it therefore seems likely that a most important one in this respect relates to conditions spermatozoa face in the female tract.

The development of a testosterone stimulation test in the Virginia opossum (Didelphis virginiana) and its use in evaluating deslorelin contraception

2008 ◽  
Vol 20 (5) ◽  
pp. 563 ◽  
Author(s):  
S. D. Johnston ◽  
F. C. Camacho ◽  
L. Carrillo ◽  
N. Guy ◽  
J. Govea ◽  
...  
Keyword(s):  
Cell Types ◽  
Didelphis Virginiana ◽  
Stimulation Test ◽  
Plasma Testosterone ◽  
Sperm Production ◽  
Testosterone Secretion ◽  
Gonadotrophin Releasing Hormone ◽  
Testicular Histology ◽  
Virginia Opossum ◽  
And Control

The aims of the present study were to examine the variability of testosterone secretion in the Virginia Opossum over a 24 h period and to develop a testosterone stimulation test that would provide an index of the prevailing testosterone biosynthetic capacity of the testes; the latter was used to clinically evaluate the efficacy of a gonadotrophin-releasing hormone agonist contraceptive. Sexually-mature captive opossums (n = 12) located in Africam Safari (Mexico) sampled every 12 h over 24 h consistently showed basal (<0.21 ng mL–1) blood testosterone concentrations. Intra-muscular injection of buserelin (2 μg mL–1) and human chorionic gonadotrophin (hCG; 1000 IU) resulted in an increase (P < 0.05) of plasma testosterone concentrations with maximal concentrations (3.9 ng mL–1 and 5.8 ng mL–1 respectively) occurring 120 min after injection. Plasma testosterone declined relatively rapidly to basal concentrations after 240 min with hCG but remained elevated after the same period of time with buserelin. Male opossums treated with (n = 6) and without (n = 6) a controlled-release deslorelin implant (Suprelorin; 4.7 mg deslorelin) were evaluated over a 10-week period for changes in testosterone secretion (hCG stimulation test) and sperm production (spermatorrhea). At the end of this period, the animals were hemi-castrated and their relative testicular quantitative histology compared. Testosterone concentration decreased over the course of the study in both treated and control animals (P < 0.0001) but there was no apparent effect of deslorelin on testosterone secretion, testicular histology (relative proportions of testicular cell types and seminiferous tubule diameter), or sperm production (presence of sperm in the cauda epididymis or urine)

scholarly journals Coronavirus and Soft Law in Germany: Business as Usual?

2021 ◽  
pp. 1-17
Author(s):  
Matthias Knauff
Keyword(s):  
Legal Order ◽  
Soft Law ◽  
Constitutional Order ◽  
Binding Forms ◽  
Almost All ◽  
Business As Usual ◽  
Shed Light ◽  
Made In

In combating the coronavirus pandemic in Germany, soft law has played an important, albeit not a central, role. Its use basically corresponds to that of under “normal circumstances”. In accordance with the German constitutional order, almost all substantial decisions are made in a legally binding form. However, these are often prepared through or supplemented by soft law. This article shows that soft law has played an important role in fighting the pandemic and its effects in Germany, although there cannot be any doubt that legally binding forms of regulation have prevailed. At the same time, the current pandemic has shed light on the advantages and effects of soft law in the context of the German legal order.

High survival rate in advanced-stage B-cell lymphomas and leukemias without CNS involvement with a short intensive polychemotherapy: results from the French Pediatric Oncology Society of a randomized trial of 216 children.

1991 ◽  
Vol 9 (1) ◽  
pp. 123-132 ◽  
Author(s):  
C Patte ◽  
T Philip ◽  
C Rodary ◽  
J M Zucker ◽  
H Behrendt ◽  
...  
Keyword(s):  
Survival Rate ◽  
B Cell ◽  
Pediatric Oncology ◽  
Stage Iv ◽  
High Dose ◽  
High Survival ◽  
Advanced Stage ◽  
High Survival Rate ◽  
Cns Involvement

From April 1984 to December 1987, the French Pediatric Oncology Society (SFOP) organized a randomized trial for advanced-stage B-cell lymphoma without CNS involvement to study the possibility of reducing the length of treatment to 4 months. After receiving the same three intensive six-drug induction courses based on high-dose fractionated cyclophosphamide, high-dose methotrexate (HD MTX), and cytarabine in continuous infusion, patients were evaluated for remission. Those who achieved complete remission (CR) were randomized between a long arm (five additional courses with two additional drugs; 16 weeks of treatment) and a short arm (two additional courses; 5 weeks). For patients in partial remission (PR), intensification of treatment was indicated. Two hundred sixteen patients were registered: 15 stage II nasopharyngeal and extensive facial tumors, 167 stage III, and 34 stage IV, 20 of the latter having more than 25% blast cells in bone marrow. The primary sites of involvement were abdomen in 172, head and neck in 30, thorax in two, and other sites in 12. One hundred sixty-seven patients are alive in first CR with a minimum follow-up of 18 months; four are lost to follow-up. Eight patients died from initial treatment failure, 14 died from toxicity or deaths unrelated to tumor or treatment, and 27 relapsed. The event-free survival (EFS), with a median follow-up of 38 months, is 78% (SE 3) for all the patients, 73% (SE 11) for the stage II patients, 80% (SE 3) for the stage III patients, and 68% (SE 8) for the stage IV and acute lymphoblastic leukemia (ALL) patients. One hundred sixty-six patients were randomized: 82 in the short arm and 84 in the long arm. EFS is, respectively, 89% and 87%. Statistical analysis confirms equivalence of both treatment arms with regard to EFS. Moreover, morbidity was lower in the short arm. This study confirms the high survival rate obtained in the previous LMB 0281 study without radiotherapy or debulking surgery and demonstrates the effectiveness of short treatment.

scholarly journals High survival rate of a critically endangered species, the Azores Bullfinch Pyrrhula murina, as a contribution to population recovery

2010 ◽  
Vol 151 (3) ◽  
pp. 627-636 ◽  
Author(s):  
David Monticelli ◽  
Ricardo Ceia ◽  
Ruben Heleno ◽  
Hugo Laborda ◽  
Sergio Timóteo ◽  
...  
Keyword(s):  
Survival Rate ◽  
Endangered Species ◽  
Critically Endangered ◽  
High Survival ◽  
Population Recovery ◽  
High Survival Rate ◽  
Critically Endangered Species

scholarly journals Repeat hepatectomy for recurrent colorectal liver metastases is associated with a high survival rate

HPB ◽  
2011 ◽  
Vol 13 (11) ◽  
pp. 774-782 ◽  
Author(s):  
Andreas Andreou ◽  
Antoine Brouquet ◽  
Eddie K. Abdalla ◽  
Thomas A. Aloia ◽  
Steven A. Curley ◽  
...  
Keyword(s):  
Survival Rate ◽  
Liver Metastases ◽  
Colorectal Liver Metastases ◽  
Repeat Hepatectomy ◽  
High Survival ◽  
High Survival Rate

Mud crab, Scylla olivacea: fattening practices in Bangladesh.

2020 ◽  
Author(s):  
Md. Younus Mia
Keyword(s):  
Operating Cost ◽  
Coastal Region ◽  
Market Value ◽  
High Survival ◽  
Net Income ◽  
Market Demand ◽  
High Survival Rate ◽  
Mud Crab ◽  
Mangrove Crab ◽  
Good Market

Abstract Fattening mud or mangrove crab, Scylla olivacea, has been practised in recent years in brackishwater ponds in Bangladesh. It is a relatively new practice in the country. Small- to medium-sized and even large but gonadal immature crabs that have low market value are bought from farmers, fishers, or from the market and stocked in fattening ponds. Fattening of crab is profitable because of fast turnover, low operating cost, high survival rate and good market demand. Two types of brackishwater earthen ponds are used to fatten crabs. One type is connected to the river through inlets and outlets to exchange water during high and ebb tides. Another type is not connected to the river but water is pumped into and discharged from the pond. The importance of fattening has been recognized as a source of income and employment to alleviate the poverty of coastal people. Through this technology, pond and ditches in the coastal region can be used throughout the year. On the basis of an interview with farmers, a net income of Tk 3,800 (US$ 65.50) can be achieved from a 120 m2 pond using the crab fattening technology. There is potential to expand crab fattening practices in coastal areas. However, an inadequate supply of stockable crab and feed are major constraints in this sector.

scholarly journals Revegetation of Rock Slopes with Different Substrates in an Abandoned Quarry in Jinju, Korea

2016 ◽  
Vol 8 (3) ◽  
pp. 26
Author(s):  
Ma Hoseop ◽  
Ettagbor Hans Enukwa ◽  
Kang Wonseok ◽  
Kim Choonsig
Keyword(s):  
Growth Rate ◽  
Survival Rate ◽  
Festuca Arundinacea ◽  
High Survival ◽  
Rock Slopes ◽  
High Survival Rate ◽  
Feasible Method ◽  
Leaf Mold ◽  
Dianthus Barbatus ◽  
Target Plant

The purpose of this research was to investigate the use of drilled slanted holes filled with different substrates in the revegetation of rock slopes. Slanted holes were drilled on rock slopes using pneumatic drillers in an abandoned limestone quarry area. These holes were filled with twelve different substrates, treated with Trichoderma harzianum. One climbing plant of Ivy (Hedera rhombea), a native woody plant (Lespedeza cyrtobotrya), three native herbaceous plants (Dianthus barbatus, Siberian chrysanthemum and Aster koraiensis) and one exotic grass plant (Festuca arundinacea) were planted in each of the soils. Six months after planting, only Ivy, Festuca arundinacea, Lespedeza cyrtobotrya and Dianthus barbatus were still observed growing on the soils, while the other plant species had already died in all the 12 soil treatments. Leaf mold soil + 50% Trichoderma harzianum provide the best conditions for revegetation of Festuca arundinacea, as this plant had its highest mean height, high survival rate, with impressive growth rate on this soil. Lespedeza cyrtobotrya also had its most favorable growth on Leaf mold soil + 50% T. harzianum. Mixed soil + 100% T. harzianum provide the best conditions for revegetation of Ivy. Leaf mold soil + 100% T. harzianum provide the best condition for revegetation of Dianthus barbatus as it had its highest mean height, highest growth rate and high survival rate on this soil. Siberian chrysanthemum and Aster koraiensis had the worse results as all of the plants died within a short period of time after planting. Ivy had the highest mean height, followed by Festuca arundinacea. The planted Ivy and Festuca arundinacea now form the vegetation of the research site which together with the substrate is now providing habitat to some wildlife like some species of centipedes, earthworms, insects and wild plants. Less than one year after planting, F. arundinacea already produced flowers and seeds which would further increase the plant population after dispersal and germination. Drilling slanted holes on rock slopes is therefore a feasible method to be used for revegetation and restoration of degraded quarries.The revegetation of steep rock slopes of quarries is a very challenging activity. However, the method of drilling slanted holes on rock slopes is a feasible method to be used for restoration of degraded quarries. These holes could serve in soil deposition and water retention that will further enhance plant growth.Methods of improving seed germination as well as enhancing growth of plants are also imperative in revegetation success of such degraded landscapes. Different percentage mixtures of T. harzianum in different soils could enhance plant growth depending on the target plant species. Different substrates could thus be used in such revegetation process depending on the target plant species.Revegetation would provide habitat and improve landscape beauty and stability, thus it is important for successful restoration of rock slopes 

scholarly journals The graffiti art and the discover of the Keith Haring’s mural in Amsterdam

2020 ◽  
pp. 236-249
Author(s):  
Caterina Soliani
Keyword(s):  
New York ◽  
Collective Memory ◽  
Street Art ◽  
Art World ◽  
Continuous Growth ◽  
The World ◽  
To Come ◽  
The Many ◽  
Shed Light ◽  
Made In

The purpose of this work is to contribute to the continuous growth of the art world (Street Art in particular) and to discuss how it is essential for the discovery of artists. These artists have been pioneers and forerunners of new pictorial techniques, freeing creative and psychological flair, and combining the latter with the artistic technology that promises great things despite limited materials.  The intention of this article is to consider the elements of artistic expression that are less commonly subject to discussion, such as the world of Street Art. This form of artwork has not always been understood or accepted, with street artists waiting for the opportune moment to express the narrative, experiences, and emotions of society through their artwork, a power that unites sentiment and encourages change.  It is art which affects the community, the population and society. It is designed above all others to become part of the collective memory through violence of image and colour.  This project led me to come into contact with one of the many artistic artefacts of the Street Art movement, the Keith Haring’s mural in Amsterdam, a piece that makes me. understand and appreciate the problems inherent to these type of works, simple, synthetic, but never simplistic.  Therefore, a project, a study and a restoration hypothesis were conducted on one of the many works by Haring. The purpose of this was to shed light once again on the mural made in 1986 by the artist, situated in the Groothandeles Market of Amsterdam. No longer visible for thirty years, the mural was covered by insulation panels placed two years after its creation. With professors Antonio Rava and William Shank, the association Keith Haring Foundation of New York, the Stedelijk Museum of Amsterdam, in collaboration with the gallery Vroom & Varossieau, specialised in road art, on 8 June, the large metal sheet panels were removed and one of the greatest murals by Haring could once again be admired.

Abstract 12091: Novel ECMO Cannulation Strategy Expedites Conversion to LVAD

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Lisa S Foley ◽  
T. B Reece ◽  
Andreas Brieke ◽  
Amrut Ambardekar ◽  
Joseph C Cleveland ◽  
...  
Keyword(s):  
Survival Rate ◽  
Cardiogenic Shock ◽  
Recovery Time ◽  
Multiple Organ ◽  
High Survival ◽  
High Survival Rate ◽  
Anterolateral Thoracotomy ◽  
Device Implantation ◽  
Organ Recovery ◽  
Va Ecmo

Objectives: Venoarterial (VA) ECMO has emerged as a successful modality for bridging patients with critical cardiogenic shock to durable support. However, LV distention on ECMO impairs RV and lung recovery and can result in the need for a temporary RVAD. Additionally, patients on VA ECMO with organ dysfunction may require ongoing LV assistance for recovery prior to durable LVAD conversion. Placement of a large apical LV vent allows bedside conversion to LVAD and provides time for organ recovery prior to elective durable device implantation. Hypothesis: We hypothesized that LV venting on ECMO accelerates RV recovery, hastening conversion to LVAD. Methods: ECMO cases from January 2012 to April 2014 were reviewed following IRB approval. Sixteen patients met INTERMACS Category 1 criteria who were placed on VA ECMO for cardiogenic or post-cardiotomy shock. Eight patients had LV venting and eight had standard peripheral cannulation. Refractory pulmonary edema, CPR during cannulation, and severe LV distention were indications for LV venting. A 32 French malleable cannula was placed by limited anterolateral thoracotomy into the LV apex. Bedside LVAD conversion was performed by percutaneous decannulation of the venous line and removal of oxygenator from circuit. Results: Conversion to temporary LVAD was successful in all LV vent cases at a mean timepoint of 5.9 (±1.3) days after LV venting compared with 13.5 (±4.9) days in non-vented patients (p = 0.07). RVAD requirement was 25% in non-vented patients and 0% in vented patients. 30-day mortality was 25% for both groups. Conclusions: LV venting as an adjunct to VA ECMO facilitates RV recovery to enable early LVAD conversion at the bedside. It also provides organ recovery time and obviates the need for a temporary RVAD at the time of durable LVAD implantation. In conclusion, the LV apical venting technique allows staged recovery of critically ill patients in biventricular and multiple organ failure with a high survival rate.

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