Modification of spermatozoa quality in mature small ruminants

2012 ◽  
Vol 24 (1) ◽  
pp. 13 ◽  
Author(s):  
G. B. Martin ◽  
T. Jorre de St Jorre ◽  
F. A. Al Mohsen ◽  
I. A. Malecki
Keyword(s):  
Large Body ◽  
Small Ruminants ◽  
Cell Loss ◽  
Testicular Tissue ◽  
The Other ◽  
Sperm Production ◽  
Testicular Mass ◽  
Other Hand ◽  
Sperm Survival ◽  
Sperm Output

This review is based largely, but not entirely, on the assumption that gamete quality is directly linked to sperm output and thus testicular mass, an approach made necessary by the absence of a large body of data on factors that affect gamete quality in ruminants. On the other hand, there is a change in the efficiency of sperm production per gram of testicular tissue when the testis is growing or shrinking, a clear indicator of changes in the rates of cell loss during the process of spermatogenesis, probably through apoptosis. We therefore postulate that the spermatozoa that do survive when the testis is shrinking are of a lower quality than those that are produced when the testis is growing and the rate of sperm survival is increasing. In adult small ruminants in particular, testicular mass and sperm production are highly labile and can be manipulated by management of photoperiod (melatonin), nutrition, genetics and behaviour (‘mating pressure’). Importantly, these factors do not act independently of each other – rather, the outcomes in terms of sperm production are dictated by interactions. It therefore seems likely that spermatozoa quality will be affected by these same factors, but definitive answers await detailed studies.

scholarly journals Lycopene supplementation prevents reactive oxygen species mediated apoptosis in Sertoli cells of adult albino rats exposed to polychlorinated biphenyls

2013 ◽  
Vol 6 (2) ◽  
pp. 83-92 ◽  
Author(s):  
Gunasekaran Krishnamoorthy ◽  
Kandaswamy Selvakumar ◽  
Prabhu Venkataraman ◽  
Perumal Elumalai ◽  
Jagadeesan Arunakaran
Keyword(s):  
Oxidative Stress ◽  
Polychlorinated Biphenyls ◽  
Sertoli Cell ◽  
Sertoli Cells ◽  
Caspase 3 ◽  
Sperm Count ◽  
Reactive Oxygen ◽  
The Other ◽  
Sperm Production ◽  
Other Hand

Abstract Sertoli cell proliferation is attenuated before attaining puberty and the number is fixed in adult testes. Sertoli cells determine both testis size and daily sperm production by providing physical and metabolic support to spermatogenic cells. Polychlorinated biphenyls (PCBs) exposure disrupts functions of Sertoli cells causing infertility with decreased sperm count. On the other hand, lycopene is improving sperm count and motility by reducing oxidative stress in humans and animals. Hence we hypothesized that PCBs-induced infertility might be due to Sertoli cell apoptosis mediated by oxidative stress and lycopene might prevent PCBs-induced apoptosis by acting against oxidative stress. To test this hypothesis, animals were treated with vehicle control, lycopene, PCBs and PCBs + lycopene for 30 days. After the experimental period, the testes and cauda epididymidis were removed for isolation of Sertoli cells and sperm, respectively. We observed increased levels of oxidative stress markers (H2O2 and LPO) levels, increased expression of apoptotic molecules (caspase-8, Bad, Bid, Bax, cytochrome C and caspase-3), decreased anti-apoptotic (Bcl2) molecule and elevated apoptotic marker activity (caspase-3) in Sertoli cells of PCBs-exposed animals. These results were associated with decreased sperm count and motility in PCBs exposed animals. On the other hand, lycopene prevented the elevation of Sertoli cellular apoptotic parameters and prevented the reduction of sperm parameters (count and motility). The data confirmed that lycopene as an antioxidant scavenged reactive oxygen substances, prevented apoptosis, maintained normal function in Sertoli cells and helped to provide physical and metabolic support for sperm production, thereby treating infertility in men.

Sixty years of research on leadership in Africa: A review of the literature

Leadership ◽  
2015 ◽  
Vol 13 (2) ◽  
pp. 222-251 ◽  
Author(s):  
Willem Fourie ◽  
Suzanne C van der Merwe ◽  
Ben van der Merwe
Keyword(s):  
Large Body ◽  
Entry Point ◽  
The Other ◽  
Review Of The Literature ◽  
Dual Purpose ◽  
Historical Literature ◽  
Other Hand ◽  
Diachronic Analysis ◽  
The One

This paper reviews peer-reviewed research on leadership in Africa published from 1950 to 2009. The review has a dual purpose. On the one hand, it provides scholars with an entry point to the relatively large body of historical literature by means of a descriptive diachronic analysis of the literature. On the other hand, it also applies a synchronic analysis, and concludes with four interpretative statements on the scholarship on leadership in Africa. These statements are: (i) Scholarship on leadership in Africa has changed, and the change is lopsided; (ii) Female scholars are increasing, and they work on different themes from male scholars; (iii) Legitimacy remains a key issue, and continues to evolve; (iv) Authenticity has become a key issue and is now closely related to reclaiming African values.

scholarly journals Analysis of small ruminants’ semen under the cooling, deep-freezing and sex-orientation method

2010 ◽  
pp. 53-58
Author(s):  
Attila Németh ◽  
Sándor Mihályfi ◽  
Tamás Szabados
Keyword(s):  
Small Ruminants ◽  
The Other ◽  
Deep Freezing ◽  
Cooling Method ◽  
Other Hand ◽  
Orientation Method ◽  
Sex Orientation

The aim of this study was to examine the influence of cooling, deep-freezing and sex-orientation methods on fertility of ram and buck semen. It was pointed out that deep-freezing and sexorientation methods had a more considerable destruction on both semen compared with the effect of cooling method. However, with the development of the sex-orientation method, the results of  lambing had a significant increase in sheep. On the other hand, the NRR of the inseminations with deep-frozen ram semen exceeded most of previously publicated results. Being interesting, and hopefully useful benefit in practice that the analysed buck semen samples are shown more favourable results in all methods compared with the same results of rams.

Canons of English Church Councils in the Early Decretal Collections

Traditio ◽  
1957 ◽  
Vol 13 ◽  
pp. 471-480 ◽  
Author(s):  
C. N. L. Brooke
Keyword(s):  
Large Body ◽  
The Other ◽  
Critical Study ◽  
Equal Weight ◽  
Other Hand ◽  
Church Councils

Neither of the two general councils of the western Church held between the Second and Third Lateran (1139, 1179) produced a large body of legislation: the genuine canons of the Council of Rheims (1148) number eighteen; those of Tours (1163) about ten. But in the great collection of Mansi this meagre store is eked out by an equal weight of additional canons, sixteen for Rheims and ten for Tours. Mansi looked on them with no great favor, but offered no criterion by which their validity and value might be judged. The Rheims canons, so far as I am aware, have never been submitted to critical study. The Tours canons, on the other hand, were examined and shown to be spurious by Seckel in a valuable appendix to his article on the sources of the canons of the English council of 1175, which he published in the Deutsche Zeitschrift für Kirchenrecht in 1899.

scholarly journals Rescue and Conservation of Male Adult Alpacas (Vicugna pacos) Based on Spermatogonial Stem Cell Biotechnology Using Atomized Black Maca as a Supplement of Cryopreservation Medium

2021 ◽  
Vol 8 ◽  
Author(s):  
Martha Valdivia ◽  
Zezé Bravo ◽  
Jhakelin Reyes ◽  
Gustavo Gonzales
Keyword(s):  
Cell Viability ◽  
Antioxidant Properties ◽  
Testicular Tissue ◽  
The Other ◽  
Mitochondrial Activity ◽  
Isolated Cells ◽  
Male Adult ◽  
Testicular Cells ◽  
Other Hand

This is the first time that testicular tissue (n = 44) and isolated testicular cells (n = 51) were cryopreserved from alpaca testes 24 h postmortem. For this purpose, internally designed freezing media and cryopreservation protocols were used. Testicular tissue fragments (25 mg) and isolated testicular cells were frozen in MTDB (trehalose and black maca), MTD (trehalose), MSDB (sucrose and black maca), and MSD (sucrose) media. Isolated spermatogonial cells were cryopreserved in two ways, before and after proliferation in vitro. After cryopreservation, the percentage of cell viability in Group 1 (>50% of cell viability) by trypan blue did not show differences within each group (p > 0.05) but showed significant differences when comparing fragments with isolated cells (p < 0.05). Spermatogonial stem cells (SSC) were identified by flow cytometry as strong Dolichos biflorus agglutinin (sDBA) and mitochondrial activity of SSC as strongly positive for MitoSense (sMitoSense+) in intact mitochondria cells, weakly positive for MitoSense (wMitoSense+) in early apoptosis, and necrosis with 7-Aminoactinomycin-D positive (7-AAD). After freezing, in Group 1M (≥30% sMitoSense+), the fragments did not show differences between the media (p > 0.05), but in the isolated cells frozen in MSDB medium, 63.68 ± 8.90% (p < 0.05). In Group 2M (<30% sMitoSense+), necrosis (7AAD+) in MSDB medium was 27.03 ± 5.80%, and necrosis in isolated cells was 14.05 ± 9.3% with significant differences between these groups (p < 0.05); in sMitoSense+, the isolated cells (34.40 ± 23%) had a higher percentage than the fragments (12.4 ± 5.2) (p < 0.05). On the other hand, MSDB and MSD media were significantly higher for isolated cells than for fragments in sDBA+ (p < 0.05). On the other hand, the SSC (sDBA+) had significant differences (p < 0.05) between fresh cells 7.43 ± 1.3% (sDBA+) compared with those cryopreserved in MSDB medium 1.46 ± 0.34% (sDBA+). Additionally, the proliferated and cryopreserved SSC 6.29 ± 1.17% (sDBA+) did not show significant differences concerning the fresh cells (p > 0.05). In conclusion, the black maca showed antioxidant properties when it was included in the freezing medium and, therefore, improved the SSC's conservation of the alpaca. Furthermore, the proliferation of isolated cells in vitro produces a higher amount of SSC after thawing them for further preclinical or clinical work.

Personality and Skin Conductance Responses to Reward and Punishment

2012 ◽  
Vol 33 (1) ◽  
pp. 17-23 ◽  
Author(s):  
Solange Mardaga ◽  
Michel Hansenne
Keyword(s):  
Decision Making ◽  
Skin Conductance ◽  
Iowa Gambling Task ◽  
Large Body ◽  
The Other ◽  
Decision Making Process ◽  
Emotional Responsiveness ◽  
Somatic Marker ◽  
Other Hand ◽  
Skin Conductance Responses

For several years now, the somatic aspect of emotions has been regarded as a major factor in the decision-making process. A large body of literature has investigated this issue, within the somatic marker hypothesis perspective, using the classical Iowa Gambling Task (IGT). Many studies reported an influence of clinical and differential factors, including personality, on IGT performance. On the other hand, personality appears to modulate the emotional responses as a function of valence (i.e., responses to rewards vs. punishments). The present study investigated whether the influence of personality on the decision-making process might be mediated by differential emotional responsiveness. Skin conductance levels were recorded in 32 subjects while performing the IGT. The results showed that novelty seeking (NS) modulated the skin conductance responses to feedback, and both NS and harm avoidance (HA) influenced anticipative response development. We also found that NS tended to modulate the final score, beyond the influence of beneficial anticipative autonomic responses. The present data partially support the hypothesis that personality-related differential emotional responsiveness may modulate somatic marker development in a decision-making situation. On the other hand, personality influence on the performance was not entirely explained by these emotional differences.

Communities as Context Providers for Web-Based Learning

2011 ◽  
pp. 135-163 ◽  
Author(s):  
Ana P. Afonso
Keyword(s):  
Network Theory ◽  
Large Body ◽  
Actor Network Theory ◽  
The Other ◽  
Web Based ◽  
Actor Network ◽  
Body Of Knowledge ◽  
Web Based Learning ◽  
Learning Contexts ◽  
Other Hand

This chapter addresses the use of communities as a context-creating approach forthe management of learning in virtual settings. It stresses the lack of consensusaround the concept of community, its recent deployment in the educationaldomain, and the extent to which the educational use of virtual settings has neg-lected the construction of appropriate learning contexts. On the other hand, itpoints to the existence of a large body of knowledge from areas such as organiza-tional learning, actor-network theory, sociology, constructivism, and learning com-munities that may help overcome the limitations of Web-based learning as it is cur-rently put into practice. The theory covered will offer a better understanding of therelationships between different concepts and trends and of learning communitiesas entirely new tools for contextual approaches to the management of learning invirtual settings.

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

Life Beyond 1MeV

1980 ◽  
Vol 38 ◽  
pp. 30-33
Author(s):  
K.H. Westmacott
Keyword(s):  
Electron Microscopy ◽  
Past Experience ◽  
The Other ◽  
Good Case ◽  
Other Hand ◽  
The U.S

Life beyond 1MeV – like life after 40 – is not too different unless one takes advantage of past experience and is receptive to new opportunities. At first glance, the returns on performing electron microscopy at voltages greater than 1MeV diminish rather rapidly as the curves which describe the well-known advantages of HVEM often tend towards saturation. However, in a country with a significant HVEM capability, a good case can be made for investing in instruments with a range of maximum accelerating voltages. In this regard, the 1.5MeV KRATOS HVEM being installed in Berkeley will complement the other 650KeV, 1MeV, and 1.2MeV instruments currently operating in the U.S. One other consideration suggests that 1.5MeV is an optimum voltage machine – Its additional advantages may be purchased for not much more than a 1MeV instrument. On the other hand, the 3MeV HVEM's which seem to be operated at 2MeV maximum, are much more expensive.

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