Richard Wassersug - Academia.edu (original) (raw)

Papers by Richard Wassersug

Journal of Men’s Health, 2021

Background and objective: Luteinizing hormone-releasing hormone agonists (LHRHa) suppress gonadal... more Background and objective: Luteinizing hormone-releasing hormone agonists (LHRHa) suppress gonadal hormone production and are commonly used to treat prostate cancer (PC) in men and conditions ranging from uterine fibroids to estrogen-sensitive cancers in women. They are also used to delay sexual development in children considering gender reassignment or experiencing premature puberty. As chemically castrating agents, LHRHa may affect cutaneous steroid secretions, which, in turn, could alter body odor and influence the psycho-sexual dynamics between individuals. The objectives of the present study were to determine (1) if LHRHa indeed alter cutaneous skin secretions, and (2) whether this leads to perceivable changes in body odor. Material and methods: Axillary skin secretions were collected on new cotton T-shirts worn by men undergoing androgen deprivation therapy with an LHRHa to treat PC (n = 10), both before starting the LHRHa and 3 months later. Healthy heterosexual university stude...

Journal of Experimental Biology, 1984

Air-breathing tadpoles of Xenopus laevis (Amphibia: Anura) use buccopharyngeal surfaces for both ... more Air-breathing tadpoles of Xenopus laevis (Amphibia: Anura) use buccopharyngeal surfaces for both gas exchange and capture of food particles in the water. In dense food suspensions, tadpoles decrease ventilation of the buccopharynx and increase air breathing. The lung ventilatory frequency is elevated even though the rate of oxygen consumption is at or below resting levels, suggesting that the lung hyperventilation reflects compensation for decreased buccopharyngeal respiration rather than an increased metabolic requirement. If tadpoles in hypoxic water are prevented from breathing air, they increase buccopharyngeal respiration at the expense of feeding. Aerial respiration evidently permits the buccopharyngeal surfaces to be used primarily for food entrapment.

Journal of Experimental Biology, 1998

The tadpole tail fin is a simple double layer of skin overlying loose connective tissue. Collagen... more The tadpole tail fin is a simple double layer of skin overlying loose connective tissue. Collagen fibres in the fin are oriented at approximately +/-45 degrees from the long axis of the tail. Three tests were conducted on samples of the dorsal tail fin from 6-10 Rana catesbeiana tadpoles to establish the fin's viscoelastic properties under (1) large-deformation cyclic loading at 1 and 3 Hz, (2) small-deformation forced vibration at 1 and 3 Hz, and (3) stress relaxation under a 0.1 s loading time. The fin was very fragile, failing easily under tensile loads less than 7 g. It was also strikingly viscoelastic, as demonstrated by 72+/-1 % hysteresis loss (at 3 Hz), 16+/-3 % stress remaining after 100 s of stress relaxation and a phase angle of 18+/-1 degrees in forced vibration. As a consequence of its viscoelastic properties, the fin was three times stiffer in small than in large deformation. This may account for the ability of the fin to stay upright during normal undulatory swimm...

Journal of Experimental Biology, 1984

Tadpoles of Xenopus laevis Daudin can extract oxygen from both air and water. When these larvae h... more Tadpoles of Xenopus laevis Daudin can extract oxygen from both air and water. When these larvae have access to air, aerial oxygen uptake averages 16.6% of total oxygen consumption in normoxic water, and increases to 100% of net oxygen consumption in hypoxic water. Neither anaerobiosis nor increased buccopharyngeal ventilation occur in response to hypoxia. If tadpoles are prevented from surfacing to breathe air, they can maintain normal oxygen consumption through aquatic respiration alone in normoxic water, but not in hypoxic water. Unlike air-breathing larvae, exclusively water-breathing larvae respond to aquatic hypoxia by increasing their buccal pumping rate and by accumulating lactate. Even though Xenopus larvae can survive without air for many days, aerial respiration is necessary for other functions: tolerance of hypoxia, normal feeding, locomotion and buoyancy regulation.

Sexual medicine, 2017

Testosterone is known to regulate male sexual interest, but the exact way that androgens influenc... more Testosterone is known to regulate male sexual interest, but the exact way that androgens influence men's sexual cognition remains unclear. To investigate the influence of androgen deprivation (AD) on visual responses to sexually suggestive stimuli in men treated for prostate cancer with AD therapy. Patients with AD-treated prostate cancer, patients with prostate cancer not on AD therapy, and age-matched healthy control participants were exposed to images of male and female runway models fully or minimally clothed. Eye tracking was used to compare looking behavior among groups. Proportion of fixations on fully clothed vs minimally clothed models and proportion of fixations on target areas of interest (ie, legs, chest, pelvis, and face) of fully clothed and minimally clothed models were analyzed and compared among groups. Although men not on AD exhibited a larger proportion of fixations on the minimally clothed compared with the fully clothed images, there was no difference betwee...

Translational andrology and urology, 2017

Erectile dysfunction (ED), the most commonly reported sexual problem for men, reduces the quality... more Erectile dysfunction (ED), the most commonly reported sexual problem for men, reduces the quality of life for both patients and their partners. Even when physiologically effective, long-term adherence to ED treatments is poor. We review here the implication of having patients' partners involved in ED treatment, starting with treatment selection. We suggest that having partners engaged from the outset may promote an erotic association of the treatment with the partner, i.e., conceptually linking the aid to the sexual pleasure that the partner provides. We hypothesize that this erotic association should enhance the sexual aid's effectiveness and might potentially help improve long-term adherence. The primary focus of this review, though, is non-pharmacological and non-surgical options for maintaining sexual activity for men with ED. Though not ED treatments per se, anecdotal data suggest that these options may be effective for some patients and their partners in regaining a sa...

BJU international, May 18, 2016

To compare quality-of-life (QoL) outcomes at 6 months between men with advanced prostate cancer r... more To compare quality-of-life (QoL) outcomes at 6 months between men with advanced prostate cancer receiving either transdermal oestradiol (tE2) or luteinising hormone-releasing hormone agonists (LHRHa) for androgen-deprivation therapy (ADT). Men with locally advanced or metastatic prostate cancer participating in an ongoing randomised, multicentre UK trial comparing tE2 versus LHRHa for ADT were enrolled into a QoL sub-study. tE2 was delivered via three or four transcutaneous patches containing oestradiol 100 μg/24 h. LHRHa was administered as per local practice. Patients completed questionnaires based on the European Organisation for Research and Treatment of Cancer quality of life questionnaire 30-item core (EORTC QLQ-C30) with prostate-specific module QLQ PR25. The primary outcome measure was global QoL score at 6 months, compared between randomised arms. In all, 727 men were enrolled between August 2007 and October 2015 (412 tE2, 315 LHRHa) with QoL questionnaires completed at bot...

Translational andrology and urology, 2016

Androgen deprivation therapy (ADT) side effects are numerous and negatively impact prostate cance... more Androgen deprivation therapy (ADT) side effects are numerous and negatively impact prostate cancer patients' quality of life. There is considerable discrepancy though among Canadian urologists regarding what ADT side effects and side effect management strategies. Little is known about global differences in ADT patient education. International respondents were recruited via online posting and at an international urology conference. Hypotheses suggest that economic and cultural differences influence patient education practices; therefore, international respondents were divided into 3 categories (high, medium, and low gross domestic product). No differences were found between responses from Canadian urologists and high GDP countries. Compared to responses from low GDP countries, Canadian urologists are more likely to endorse informing patients about: osteoporosis, loss of muscle mass, weight gain, fatigue/sleep disturbance, relationship changes, cognitive changes, and loss of body ...

EvoDevo, 2016

The Neotropical frog genera Ceratophrys, Chacophrys and Lepidobatrachus form the monophyletic fam... more The Neotropical frog genera Ceratophrys, Chacophrys and Lepidobatrachus form the monophyletic family Ceratophryidae. Although in- and out-group relationships are not fully resolved, the monophyly of the three genera is well supported by both morphological and molecular data. Much is known about the morphology of the ceratophryids, but there is little comparative information on how modification of a common ancestral developmental pathway played a role in shaping their particular body plans. Herein, we review morphological variation during ceratophryid ontogeny in order to explore the role of development in their evolution. The ceratophryids are collectively characterized by rapid larval development with respect to other anurans, yet the three genera differ in their postmetamorphic growth rates to sexual maturity. Derived traits in the group can be divided into many homoplastic features that evolved in parallel with those of anurans with fossorial/burrowing behaviors in semiarid envir...

The Journal of Sexual Medicine, 2015

Smithsonian Contributions to Zoology, 1988

Biological Sciences in Space, 1997

Canadian Oncology Nursing Journal, 2014

Applied Herpetology, 2007

Global Health Promotion, 2014

The unprecedented success of the Movember campaign in raising money for, and awareness of, prosta... more The unprecedented success of the Movember campaign in raising money for, and awareness of, prostate cancer (PCa) brings with it a novel opportunity to consider how masculinity and men’s health can connect. In this essay we first detail the history of some less fruitful endeavors for advancing PCa awareness that played on masculine stereotypes. We then consider how Movember’s moustache motif has succeeded. Included are commentaries about why the strongly masculine motifs of combat, loyalty, and aggression couched in military language were not successful when used to promote concern about men’s health. Movember in contrast succeeds by focusing on a way that men can express their individuality without resorting to overt acts or signs of aggression or militarism.

Journal of Experimental Biology, 2013

Summary Anuran larvae, which are otherwise simple in shape, typically have complex keratinized mo... more Summary Anuran larvae, which are otherwise simple in shape, typically have complex keratinized mouthparts (i.e., labial teeth and jaw sheaths) that allow them to graze upon surfaces. The diversity in these structures among species presumably reflects specializations that allow for maximal feeding efficiency on different types of food. However, we lack a general understanding of how these oral structures function during feeding. We used high-speed digital imaging (500 Hz) to observe tadpoles of six species from the anuran family Hylidae grazing on a standardized food-covered substrate. Tadpoles of these species vary in the number of labial tooth rows, belong to two different feeding guilds (benthic and nektonic), and inhabit ponds and streams. We confirmed that the labial teeth in these species serve two functions; anchoring the mouth to the substrate and raking material off of the substrate. In general, tadpoles with a larger maximum gape and those with fewer labial tooth rows opene...

Proceedings of the National Academy of Sciences, 1995

To test whether gravity is required for normal amphibian development, Xenopus laevis females were... more To test whether gravity is required for normal amphibian development, Xenopus laevis females were induced to ovulate aboard the orbiting Space Shuttle. Eggs were fertilized in vitro, and although early embryonic stages showed some abnormalities, the embryos were able to regulate and produce nearly normal larvae. These results demonstrate that a vertebrate can ovulate in the virtual absence of gravity and that the eggs can develop to a free-living stage.

Perspectives in Biology and Medicine, 2007

Journal of Men’s Health, 2021

Background and objective: Luteinizing hormone-releasing hormone agonists (LHRHa) suppress gonadal... more Background and objective: Luteinizing hormone-releasing hormone agonists (LHRHa) suppress gonadal hormone production and are commonly used to treat prostate cancer (PC) in men and conditions ranging from uterine fibroids to estrogen-sensitive cancers in women. They are also used to delay sexual development in children considering gender reassignment or experiencing premature puberty. As chemically castrating agents, LHRHa may affect cutaneous steroid secretions, which, in turn, could alter body odor and influence the psycho-sexual dynamics between individuals. The objectives of the present study were to determine (1) if LHRHa indeed alter cutaneous skin secretions, and (2) whether this leads to perceivable changes in body odor. Material and methods: Axillary skin secretions were collected on new cotton T-shirts worn by men undergoing androgen deprivation therapy with an LHRHa to treat PC (n = 10), both before starting the LHRHa and 3 months later. Healthy heterosexual university stude...

Journal of Experimental Biology, 1984

Air-breathing tadpoles of Xenopus laevis (Amphibia: Anura) use buccopharyngeal surfaces for both ... more Air-breathing tadpoles of Xenopus laevis (Amphibia: Anura) use buccopharyngeal surfaces for both gas exchange and capture of food particles in the water. In dense food suspensions, tadpoles decrease ventilation of the buccopharynx and increase air breathing. The lung ventilatory frequency is elevated even though the rate of oxygen consumption is at or below resting levels, suggesting that the lung hyperventilation reflects compensation for decreased buccopharyngeal respiration rather than an increased metabolic requirement. If tadpoles in hypoxic water are prevented from breathing air, they increase buccopharyngeal respiration at the expense of feeding. Aerial respiration evidently permits the buccopharyngeal surfaces to be used primarily for food entrapment.

Journal of Experimental Biology, 1998

The tadpole tail fin is a simple double layer of skin overlying loose connective tissue. Collagen... more The tadpole tail fin is a simple double layer of skin overlying loose connective tissue. Collagen fibres in the fin are oriented at approximately +/-45 degrees from the long axis of the tail. Three tests were conducted on samples of the dorsal tail fin from 6-10 Rana catesbeiana tadpoles to establish the fin's viscoelastic properties under (1) large-deformation cyclic loading at 1 and 3 Hz, (2) small-deformation forced vibration at 1 and 3 Hz, and (3) stress relaxation under a 0.1 s loading time. The fin was very fragile, failing easily under tensile loads less than 7 g. It was also strikingly viscoelastic, as demonstrated by 72+/-1 % hysteresis loss (at 3 Hz), 16+/-3 % stress remaining after 100 s of stress relaxation and a phase angle of 18+/-1 degrees in forced vibration. As a consequence of its viscoelastic properties, the fin was three times stiffer in small than in large deformation. This may account for the ability of the fin to stay upright during normal undulatory swimm...

Journal of Experimental Biology, 1984

Tadpoles of Xenopus laevis Daudin can extract oxygen from both air and water. When these larvae h... more Tadpoles of Xenopus laevis Daudin can extract oxygen from both air and water. When these larvae have access to air, aerial oxygen uptake averages 16.6% of total oxygen consumption in normoxic water, and increases to 100% of net oxygen consumption in hypoxic water. Neither anaerobiosis nor increased buccopharyngeal ventilation occur in response to hypoxia. If tadpoles are prevented from surfacing to breathe air, they can maintain normal oxygen consumption through aquatic respiration alone in normoxic water, but not in hypoxic water. Unlike air-breathing larvae, exclusively water-breathing larvae respond to aquatic hypoxia by increasing their buccal pumping rate and by accumulating lactate. Even though Xenopus larvae can survive without air for many days, aerial respiration is necessary for other functions: tolerance of hypoxia, normal feeding, locomotion and buoyancy regulation.

Sexual medicine, 2017

Testosterone is known to regulate male sexual interest, but the exact way that androgens influenc... more Testosterone is known to regulate male sexual interest, but the exact way that androgens influence men's sexual cognition remains unclear. To investigate the influence of androgen deprivation (AD) on visual responses to sexually suggestive stimuli in men treated for prostate cancer with AD therapy. Patients with AD-treated prostate cancer, patients with prostate cancer not on AD therapy, and age-matched healthy control participants were exposed to images of male and female runway models fully or minimally clothed. Eye tracking was used to compare looking behavior among groups. Proportion of fixations on fully clothed vs minimally clothed models and proportion of fixations on target areas of interest (ie, legs, chest, pelvis, and face) of fully clothed and minimally clothed models were analyzed and compared among groups. Although men not on AD exhibited a larger proportion of fixations on the minimally clothed compared with the fully clothed images, there was no difference betwee...

Translational andrology and urology, 2017

Erectile dysfunction (ED), the most commonly reported sexual problem for men, reduces the quality... more Erectile dysfunction (ED), the most commonly reported sexual problem for men, reduces the quality of life for both patients and their partners. Even when physiologically effective, long-term adherence to ED treatments is poor. We review here the implication of having patients' partners involved in ED treatment, starting with treatment selection. We suggest that having partners engaged from the outset may promote an erotic association of the treatment with the partner, i.e., conceptually linking the aid to the sexual pleasure that the partner provides. We hypothesize that this erotic association should enhance the sexual aid's effectiveness and might potentially help improve long-term adherence. The primary focus of this review, though, is non-pharmacological and non-surgical options for maintaining sexual activity for men with ED. Though not ED treatments per se, anecdotal data suggest that these options may be effective for some patients and their partners in regaining a sa...

BJU international, May 18, 2016

To compare quality-of-life (QoL) outcomes at 6 months between men with advanced prostate cancer r... more To compare quality-of-life (QoL) outcomes at 6 months between men with advanced prostate cancer receiving either transdermal oestradiol (tE2) or luteinising hormone-releasing hormone agonists (LHRHa) for androgen-deprivation therapy (ADT). Men with locally advanced or metastatic prostate cancer participating in an ongoing randomised, multicentre UK trial comparing tE2 versus LHRHa for ADT were enrolled into a QoL sub-study. tE2 was delivered via three or four transcutaneous patches containing oestradiol 100 μg/24 h. LHRHa was administered as per local practice. Patients completed questionnaires based on the European Organisation for Research and Treatment of Cancer quality of life questionnaire 30-item core (EORTC QLQ-C30) with prostate-specific module QLQ PR25. The primary outcome measure was global QoL score at 6 months, compared between randomised arms. In all, 727 men were enrolled between August 2007 and October 2015 (412 tE2, 315 LHRHa) with QoL questionnaires completed at bot...

Translational andrology and urology, 2016

Androgen deprivation therapy (ADT) side effects are numerous and negatively impact prostate cance... more Androgen deprivation therapy (ADT) side effects are numerous and negatively impact prostate cancer patients' quality of life. There is considerable discrepancy though among Canadian urologists regarding what ADT side effects and side effect management strategies. Little is known about global differences in ADT patient education. International respondents were recruited via online posting and at an international urology conference. Hypotheses suggest that economic and cultural differences influence patient education practices; therefore, international respondents were divided into 3 categories (high, medium, and low gross domestic product). No differences were found between responses from Canadian urologists and high GDP countries. Compared to responses from low GDP countries, Canadian urologists are more likely to endorse informing patients about: osteoporosis, loss of muscle mass, weight gain, fatigue/sleep disturbance, relationship changes, cognitive changes, and loss of body ...

EvoDevo, 2016

The Neotropical frog genera Ceratophrys, Chacophrys and Lepidobatrachus form the monophyletic fam... more The Neotropical frog genera Ceratophrys, Chacophrys and Lepidobatrachus form the monophyletic family Ceratophryidae. Although in- and out-group relationships are not fully resolved, the monophyly of the three genera is well supported by both morphological and molecular data. Much is known about the morphology of the ceratophryids, but there is little comparative information on how modification of a common ancestral developmental pathway played a role in shaping their particular body plans. Herein, we review morphological variation during ceratophryid ontogeny in order to explore the role of development in their evolution. The ceratophryids are collectively characterized by rapid larval development with respect to other anurans, yet the three genera differ in their postmetamorphic growth rates to sexual maturity. Derived traits in the group can be divided into many homoplastic features that evolved in parallel with those of anurans with fossorial/burrowing behaviors in semiarid envir...

The Journal of Sexual Medicine, 2015

Smithsonian Contributions to Zoology, 1988

Biological Sciences in Space, 1997

Canadian Oncology Nursing Journal, 2014

Applied Herpetology, 2007

Global Health Promotion, 2014

The unprecedented success of the Movember campaign in raising money for, and awareness of, prosta... more The unprecedented success of the Movember campaign in raising money for, and awareness of, prostate cancer (PCa) brings with it a novel opportunity to consider how masculinity and men’s health can connect. In this essay we first detail the history of some less fruitful endeavors for advancing PCa awareness that played on masculine stereotypes. We then consider how Movember’s moustache motif has succeeded. Included are commentaries about why the strongly masculine motifs of combat, loyalty, and aggression couched in military language were not successful when used to promote concern about men’s health. Movember in contrast succeeds by focusing on a way that men can express their individuality without resorting to overt acts or signs of aggression or militarism.

Journal of Experimental Biology, 2013

Summary Anuran larvae, which are otherwise simple in shape, typically have complex keratinized mo... more Summary Anuran larvae, which are otherwise simple in shape, typically have complex keratinized mouthparts (i.e., labial teeth and jaw sheaths) that allow them to graze upon surfaces. The diversity in these structures among species presumably reflects specializations that allow for maximal feeding efficiency on different types of food. However, we lack a general understanding of how these oral structures function during feeding. We used high-speed digital imaging (500 Hz) to observe tadpoles of six species from the anuran family Hylidae grazing on a standardized food-covered substrate. Tadpoles of these species vary in the number of labial tooth rows, belong to two different feeding guilds (benthic and nektonic), and inhabit ponds and streams. We confirmed that the labial teeth in these species serve two functions; anchoring the mouth to the substrate and raking material off of the substrate. In general, tadpoles with a larger maximum gape and those with fewer labial tooth rows opene...

Proceedings of the National Academy of Sciences, 1995

To test whether gravity is required for normal amphibian development, Xenopus laevis females were... more To test whether gravity is required for normal amphibian development, Xenopus laevis females were induced to ovulate aboard the orbiting Space Shuttle. Eggs were fertilized in vitro, and although early embryonic stages showed some abnormalities, the embryos were able to regulate and produce nearly normal larvae. These results demonstrate that a vertebrate can ovulate in the virtual absence of gravity and that the eggs can develop to a free-living stage.

Perspectives in Biology and Medicine, 2007