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Reversibility of Vasalgel™ male contraceptive in a rabbit model

Overview of attention for article published in Basic and Clinical Andrology, April 2017
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  • In the top 5% of all research outputs scored by Altmetric
  • High Attention Score compared to outputs of the same age (97th percentile)

Mentioned by

13 news outlets
22 tweeters
1 Facebook page
1 Redditor


9 Dimensions

Readers on

22 Mendeley
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Reversibility of Vasalgel™ male contraceptive in a rabbit model
Published in
Basic and Clinical Andrology, April 2017
DOI 10.1186/s12610-017-0051-1
Pubmed ID

Donald Waller, David Bolick, Elaine Lissner, Christopher Premanandan, Gary Gamerman


Development of a non-hormonal long-acting reversible contraceptive for men could have a significant impact on reducing unintended pregnancies. Vasalgel™ is a high molecular weight polymer consisting of styrene-alt-maleic acid (SMA) dissolved in dimethyl sulfoxide being developed as a reversible male contraceptive device. It forms a hydrogel when implanted into the vasa deferentia, which prevents the passage of sperm. Previous studies in the rabbit have proven its efficacy, durability and rapid onset. This study evaluates the capacity to restore sperm concentrations in ejaculates after a reversal procedure. Sodium bicarbonate was injected into the vasa deferentia after fourteen months of azoospermia following the injection of two device variations (Vasalgel 100 and Vasalgel 80). Semen samples were then collected for six months and sperm characteristics were compared to baseline levels. Samples of vasa deferentia were obtained for histological examination. Spermatozoa were present in all subject ejaculates after the reversal procedure. Sperm concentration and sperm motility were similar to baseline levels after reversal, while sperm forward progression was significantly lower and normal acrosomes were not observed. Forward progression percentages increased linearly during six months of semen collection, however, normal acrosomes were not observed at the conclusion of the study. Histologically, several vasa deferentia were clear of the device and contained an intact epithelial lining. A smaller proportion of tissues contained residual test material. A secondary intraluminal inflammatory response was seen occasionally in the tissues containing residual material. There was no difference between the two device variations for studied parameters. Vasalgel's prevention of sperm transport for 14 months was reversed through an intravasal injection of sodium bicarbonate. Post-reversal sperm concentrations and motility returned to baseline levels during the six-month follow up. Residual material in the vas lumen or compromised epididymal and vas deferens function may be resulting in reduced forward progression and loss of acrosomes during transit through the vas. Reduced forward progression and the lack of normal acrosomes strongly suggest impaired sperm function.

Twitter Demographics

The data shown below were collected from the profiles of 22 tweeters who shared this research output. Click here to find out more about how the information was compiled.

Mendeley readers

The data shown below were compiled from readership statistics for 22 Mendeley readers of this research output. Click here to see the associated Mendeley record.

Geographical breakdown

Country Count As %
Unknown 22 100%

Demographic breakdown

Readers by professional status Count As %
Student > Master 6 27%
Student > Bachelor 5 23%
Researcher 4 18%
Student > Doctoral Student 2 9%
Student > Ph. D. Student 2 9%
Other 3 14%
Readers by discipline Count As %
Medicine and Dentistry 9 41%
Nursing and Health Professions 4 18%
Biochemistry, Genetics and Molecular Biology 2 9%
Engineering 2 9%
Psychology 1 5%
Other 3 14%
Unknown 1 5%

Attention Score in Context

This research output has an Altmetric Attention Score of 126. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 13 January 2020.
All research outputs
of 14,162,642 outputs
Outputs from Basic and Clinical Andrology
of 63 outputs
Outputs of similar age
of 264,554 outputs
Outputs of similar age from Basic and Clinical Andrology
of 2 outputs
Altmetric has tracked 14,162,642 research outputs across all sources so far. Compared to these this one has done particularly well and is in the 99th percentile: it's in the top 5% of all research outputs ever tracked by Altmetric.
So far Altmetric has tracked 63 research outputs from this source. They typically receive a lot more attention than average, with a mean Attention Score of 33.4. This one has done particularly well, scoring higher than 95% of its peers.
Older research outputs will score higher simply because they've had more time to accumulate mentions. To account for age we can compare this Altmetric Attention Score to the 264,554 tracked outputs that were published within six weeks on either side of this one in any source. This one has done particularly well, scoring higher than 97% of its contemporaries.
We're also able to compare this research output to 2 others from the same source and published within six weeks on either side of this one. This one has scored higher than all of them