scholarly journals Characterisation of the biological effects of neurohypophysial peptides on seminiferous tubules

1998 ◽  
Vol 156 (1) ◽  
pp. 35-42 ◽  
Author(s):  
GC Harris ◽  
HD Nicholson
Keyword(s):  
Seminiferous Tubule ◽  
Contractile Response ◽  
Contractile Activity ◽  
Biological Effects ◽  
Time Lapse ◽  
Seminiferous Tubules ◽  
Computer Assisted ◽  
Induced Responses ◽  
Adult Rat ◽  
Assisted Analysis

Oxytocin (OT) is present in the mammalian testis and has been postulated to play a role in modulation of seminiferous tubule contractility. However, recent evidence suggests that the myoid cells responsible for such contractile activity do not express OT receptors. In this study computer-assisted analysis and time-lapse videomicrography were used to investigate the biological effects of neurohypophysial peptides and their analogues on seminiferous tubule contractility. Adult rat testes were placed in fresh oxygenated Dulbecco's modified Eagle's medium (DMEM) F12 medium, decapsulated and the tubules gently teased apart. A small section of tubule was placed in a microslide chamber and perifused with medium. Seminiferous tubules were treated with OT (2 nM), [Arg8]-vasopressin (AVP, 0.2 nM) or [Thr4,Gly7]-OT (TGOT, 2 nM, 8 nM and 0.2 microM). Specific antagonists were also given simultaneously with OT and AVP treatments. Data were analysed to give arbitrary units of contractility. Both OT and AVP increased tubule contractility, with AVP being at least 10 times more potent than OT. Treatment with the selective OT antagonist, desGly-NH2,d(CH2)5[d-Tyr2,Thr4]-ornithine vasotocin (OTA, 0.2 microM and 2 microM) significantly reduced OT-induced increases in seminiferous tubule contractility but had no effect on AVP-induced responses. In contrast, the AVP antagonist, Phaa-d-Tyr(Me)-Phe-Gln-Asn-Arg-Pro-Arg-Tyr-NH2 (AVPA) was more potent at reducing AVP-induced increases than OT-induced responses. The selective non-peptide AVPA SR 49059 blocked the response to both peptides in a similar manner, whilst the non-peptide OTA L367,773 did not block OT-induced increases in seminiferous tubule contractility at doses that were slightly inhibitory to AVP-induced responses. The specific OT agonist TGOT did not induce a contractile response. The data in this study demonstrate that in the testis AVP acts via V1a receptors to stimulate contractile activity and suggest that OT may act via a receptor which differs from the classical V1a and uterine-type OT receptor. These findings support a role for OT in the regulation of seminiferous tubule contractility and raise the possibility that AVP may also be important in this process.

scholarly journals Stage-related differences in rat seminiferous tubule contractility in vitro and their response to oxytocin

1998 ◽  
Vol 157 (2) ◽  
pp. 251-257 ◽  
Author(s):  
GC Harris ◽  
HD Nicholson
Keyword(s):  
Seminiferous Tubule ◽  
Contractile Activity ◽  
Control Period ◽  
Time Lapse ◽  
Seminiferous Tubules ◽  
Computer Assisted ◽  
Adult Rat ◽  
Specific Effects ◽  
Assisted Analysis

Oxytocin (OT) is present in the mammalian testis and has been shown to play a role in the modulation of seminiferous tubule contractility and steroidogenesis. However, stage-specific effects of the peptide have not been previously investigated. In this study, computer-assisted analysis and time-lapse videomicrography were used to investigate basal contractility and the response to OT of seminiferous tubules at specific stages of the spermatogenic cycle. Adult rat testes were placed in fresh oxygenated DMEM F12 medium, decapsulated, and the tubules gently teased apart. Stages were identified by transillumination and a 10 mm section of tubule at each of stages IV-V, VII-VIII and XIII-I was placed in a microslide chamber and perifused with medium. After a control period of 3 h, OT (2 nM) was given for 1 h, followed by another control period of 1 h. The experiment was repeated using tubules from different rats and data were analysed to give arbitrary units of tubule contractility. Contractility was observed in all the tubules studied and the contractile activity was shown to vary depending on the stage of the spermatogenic cycle. Mean basal contractility at stages VII-VIII, the time when sperm are shed from the epithelium, was significantly lower than that at stages IV-V and XIII-I. The response of the tubules to OT was also stage-dependent, with the peptide producing the largest increases in contractile activity at stages VII-VIII and having no effect at stages IV-V. We postulate that these stage-specific differences in basal and OT-stimulated contractility may be important in co-ordinating the movement of developing germ cells towards the lumen of the seminiferous epithelium and in the process of spermiation.

Ethan-1,2-dimethanesulphonate reduces testicular oxytocin content and seminiferous tubule movements in the rat

1987 ◽  
Vol 112 (2) ◽  
pp. 311-NP ◽  
Author(s):  
H. D. Nicholson ◽  
R. T. S. Worley ◽  
S. E. F. Guldenaar ◽  
B. T. Pickering
Keyword(s):  
Leydig Cell ◽  
Seminiferous Tubule ◽  
Leydig Cells ◽  
Contractile Activity ◽  
Histological Study ◽  
Interstitial Cells ◽  
Seminiferous Tubules ◽  
Adult Rats ◽  
Adult Rat

ABSTRACT An oxytocin-like peptide is present in the interstitial cells of the testis, and testicular concentrations of oxytocin have been shown to increase seminiferous tubule movements in vitro. We have used the drug ethan-1,2-dimethanesulphonate (EDS), which depletes the Leydig cell population of the adult rat testis, to examine further the relationships between the Leydig cell, testicular oxytocin and tubular movements. Adult rats were injected i.p. with a single dose of EDS (75 mg/kg) or of vehicle (25% dimethyl sulphoxide). Histological study 3 and 10 days after treatment with EDS showed a reduction in the number of interstitial cells, and levels of oxytocin immunoreactivity were undetectable by radioimmunoassay. Immunostaining revealed very few oxytocin-reactive cells. Spontaneous contractile activity of the seminiferous tubules in vitro was also dramatically reduced, but could be restored by the addition of oxytocin to the medium. Four weeks after EDS treatment, the interstitial cells were similar to those in the control animals both in number and in immunostaining; immunoassayable oxytocin was present and tubular movements were normal. The EDS effect, seen at 3 and 10 days, was not altered by daily treatment with testosterone. However, repopulation of the testes with oxytocin-immunoreactive cells was not seen until 6 weeks in the testosterone-treated animals. We suggest that the Leydig cells are the main source of oxytocin immunoreactivity in the testis and that this oxytocin is involved in modulating seminiferous tubule movements and the resultant sperm transport. The results also imply that testosterone does not play a major role in controlling tubular activity in the mature rat. J. Endocr. (1987) 112, 311–316

Computer-assisted analysis of time-lapse cinemicrographs of cultured cells

1978 ◽  
Vol 11 (4) ◽  
pp. 363-379 ◽  
Author(s):  
A.P. Tolmach ◽  
A.R. Mitz ◽  
S.L. Von Rump ◽  
M.L. Pepper ◽  
L.J. Tolmach
Keyword(s):  
Cultured Cells ◽  
Time Lapse ◽  
Computer Assisted ◽  
Assisted Analysis

LH and testosterone cause the development of seminiferous tubule contractile activity and the appearance of testicular oxytocin in hypogonadal mice

1986 ◽  
Vol 110 (1) ◽  
pp. 159-167 ◽  
Author(s):  
H. D. Nicholson ◽  
R. T. S. Worley ◽  
H. M. Charlton ◽  
B. T. Pickering
Keyword(s):  
Seminiferous Tubule ◽  
Adult Mouse ◽  
Contractile Activity ◽  
Normal Adult ◽  
Seminiferous Tubules ◽  
Releasing Hormone ◽  
Adult Mice ◽  
Low Levels ◽  
Lh Releasing Hormone ◽  
The Relationship

ABSTRACT Immunoreactive oxytocin is present in the testis and it has been shown that this hormone increases the contractility of seminiferous tubules. We have investigated the relationship between testicular oxytocin, tubular movements and the effects of LH and testosterone using, as a model, the hypogonadal (hpg/hpg) mouse, which is deficient in hypothalamic LH-releasing hormone (LHRH). Whilst both testicular oxytocin and seminiferous tubule movements, resembling those seen in the rat, can be found in normal adult mice, neither can be found in hypogonadal mice. After 2 weeks of treatment with LH (200 ng to 100 μg daily) low levels of testicular oxytocin and tubular movements were observed. Treatment with large doses of testosterone for 2–12 weeks led to higher concentrations of testicular oxytocin and tubular movements resembling those seen in the normal adult mouse. The results support the evidence that testicular oxytocin modulates seminiferous tubule movements. We suggest that testosterone may play a part in the accumulation of oxytocin in the testis. J. Endocr. (1986) 110, 159–167

Computer-Assisted Analysis of Multi-Color Confocal Microscopic Datasets: Automated Light Microscopic Discrimination of Synaptic Relationships

1996 ◽  
Vol 54 ◽  
pp. 284-285
Author(s):  
M Wessendorf ◽  
A Beuning ◽  
D Cameron ◽  
J Williams ◽  
C Knox
Keyword(s):  
Nerve Fibers ◽  
Confocal Scanning Laser Microscopy ◽  
Computer Assisted ◽  
Nerve Terminals ◽  
Neuronal Somata ◽  
Scanning Laser Microscopy ◽  
Confocal Scanning ◽  
Entire Cell ◽  
Confocal Scanning Laser ◽  
Assisted Analysis

Multi-color confocal scanning-laser microscopy (CSLM) allows examination of the relationships between neuronal somata and the nerve fibers surrounding them at sub-micron resolution in x,y, and z. Given these properties, it should be possible to use multi-color CSLM to identify relationships that might be synapses and eliminate those that are clearly too distant to be synapses. In previous studies of this type, pairs of images (e.g., red and green images for tissue stained with rhodamine and fluorescein) have been merged and examined for nerve terminals that appose a stained cell (see, for instance, Mason et al.). The above method suffers from two disadvantages, though. First, although it is possible to recognize appositions in which the varicosity abuts the cell in the x or y axes, it is more difficult to recognize them if the apposition is oriented at all in the z-axis—e.g., if the varicosity lies above or below the neuron rather than next to it. Second, using this method to identify potential appositions over an entire cell is time-consuming and tedious.

scholarly journals Syllabification of the Divine Comedy

2021 ◽  
Vol 14 (3) ◽  
pp. 1-26
Author(s):  
Andrea Asperti ◽  
Stefano Dal Bianco
Keyword(s):  
Text Processing ◽  
Solution Space ◽  
Generative Models ◽  
Divine Comedy ◽  
Point Of View ◽  
Computer Assisted ◽  
Wide Range ◽  
The Divine Comedy ◽  
Left And Right ◽  
Assisted Analysis

We provide a syllabification algorithm for the Divine Comedy using techniques from probabilistic and constraint programming. We particularly focus on the synalephe , addressed in terms of the "propensity" of a word to take part in a synalephe with adjacent words. We jointly provide an online vocabulary containing, for each word, information about its syllabification, the location of the tonic accent, and the aforementioned synalephe propensity, on the left and right sides. The algorithm is intrinsically nondeterministic, producing different possible syllabifications for each verse, with different likelihoods; metric constraints relative to accents on the 10th, 4th, and 6th syllables are used to further reduce the solution space. The most likely syllabification is hence returned as output. We believe that this work could be a major milestone for a lot of different investigations. From the point of view of digital humanities it opens new perspectives on computer-assisted analysis of digital sources, comprising automated detection of anomalous and problematic cases, metric clustering of verses and their categorization, or more foundational investigations addressing, e.g., the phonetic roles of consonants and vowels. From the point of view of text processing and deep learning, information about syllabification and the location of accents opens a wide range of exciting perspectives, from the possibility of automatic learning syllabification of words and verses to the improvement of generative models, aware of metric issues, and more respectful of the expected musicality.

scholarly journals Chiming In: A Computer-Assisted Analysis of Popular Musicians’ Political Engagement on Twitter

2021 ◽  
Vol 7 (2) ◽  
pp. 205630512110190
Author(s):  
Josephine Lukito ◽  
Luis Loya ◽  
Carlos Dávalos ◽  
Jianing Li ◽  
Chau Tong ◽  
...  
Keyword(s):  
Case Studies ◽  
Hip Hop ◽  
Political Engagement ◽  
Future Research ◽  
Computer Assisted ◽  
Christian Music ◽  
Political Issues ◽  
Qualitative Case Studies ◽  
Systematic Examination ◽  
Assisted Analysis

While music as an artistic form is well studied, the individuals behind the art receive relatively less attention. In this article, we provide evidence of celebrity advocacy with a systematic examination of musicians’ political engagement on Twitter. This study estimates the extent to which musicians use Twitter for political purposes, with particular attention to whether such engagement varies across music genres. Through a computational-assisted analysis of 2,286,434 tweets, we group 881 musicians into three categories of political engagement on Twitter: not engaged (comprising the majority of artists), circumstantial engagement, and active political engagement. We examine the latter categories in detail with two qualitative case studies. The findings indicate that musicians from different genres have distinct patterns of political engagement. The Christian music genre shows the most engagement as a whole, especially in philanthropy. On the contrary, the most active accounts are rock and hip-hop artists, some of whom discuss political issues and call for mobilization. We conclude with suggestions for future research.

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