Risk Factors for Penile Fracture After Intralesional Collagenase Clostridium histolyticum in Peyronie's Disease

OBJECTIVE

To evaluate risk factors leading to corporal rupture after Collagenase Clostridium histolyticum (CCh). Peyronie's disease (PD) is a fibrotic condition of the penis characterized by abnormal plaque formation. Intralesional CCh is the only FDA-approved medication for PD, however, it can lead to corporal rupture, a potential surgical emergency.

METHODS

We retrospectively reviewed medical records from Veterans diagnosed with PD who were under treatment with CCh using the Veterans Administration Informatics and Computing Infrastructure (VINCI). Using International Classification of Diseases and Current Procedural Terminology codes, we identified men who suffered a corporal rupture after CCh. Individual charts were reviewed to determine potential risk factors and events leading to corporal rupture.

RESULTS

We identified 17,647 veterans who were diagnosed with PD, of which 8.7% (1541) received at least one injection of CCh for PD. Of them, 0.7% (11/1541) veterans suffered corporal rupture. Within these 11 patients, the median number of CCH injections was 6 with a median initial curvature of 35°. Fracture occurred at a median of 8days after CCH injection. The majority of fractures were secondary to spontaneous erections or sexual intercourse. Finally, six patients had their fracture repaired surgically while the remaining were managed conservatively.

CONCLUSION

Most fractures occurred within 2weeks of CCh injections and were associated with sexual intercourse and spontaneous morning erections.

Diagnosis and treatment patterns of Peyronie's disease among different racial, ethnic, and regional groups in the Veterans Affairs healthcare system

Peyronie's Disease, which is known to have racial/ethnic disparities in the general population, has never been studied in the veteran population. We compared the diagnosis and treatment rates for Peyronie's Disease among United States veterans of various racial-ethnic backgrounds at Veterans Affairs medical centers, which are equal-access systems. We queried the Veterans Affair Informatics and Computing Infrastructure to identify 17,647 Peyronie's Disease patients in the United States by ICD-9 or ICD-10 code between 2015-2020. We assessed demographic characteristics, clinical characteristics, Veterans Affairs facility information, and treatment patterns. Racial-ethnic demographics of veterans with Peyronie's Disease were 71.4% White, 15.4% Black, 5.8% Hispanic, 1.6% Native American, 0.3% Asian, and 5.4% unknown. Treatment rate was 13.6% overall, 13.6% of Whites (ref), 14.3% of Blacks (p = 0.2985), 13.5% of Hispanics (p = 0.9205), 9.1% of Asians (p = 0.3319), 16.7% of Native Americans (p = 0.1406), and 9.6% of unknown (p = 0.0041). White patients were more likely to receive injectional therapy and less likely to undergo surgery than Black patients. Peyronie's Disease patients at Veterans Affairs facilities are treated at the same rate, indicating that equal-access healthcare systems may mitigate racial-ethnic disparities. Further research is necessary to account for differences in disease severity and Veterans Affairs surgeon availability.

A multi-institutional study of 1,111 men with 4K score, multiparametric magnetic resonance imaging, and prostate biopsy

OBJECTIVE

Prostate magnetic resonance imaging (MRI) and biomarkers are often used in conjunction to enhance the selection process for prostate biopsy. However, the optimal sequence of ordering these tests has not been established. A comprehensive evaluation was conducted on a large multi-institutional cohort of patients who underwent MRI, 4K score, and biopsy of the prostate to examine the impact of utilizing both tests vs. either test alone and to determine if the order in which these tests are administered affects the ability to detect clinically significant prostate cancer (csCaP).

METHODS AND MATERIALS

We evaluated men from 8 different institutions who were referred for prostate cancer evaluation and underwent MRI, 4K score test, and prostate biopsy. The primary outcome was the presence of csCaP, defined as grade group 2 or higher cancer on a biopsy of the prostate. We used logistic regression, calibration plots, and decision curve analysis to evaluate using a 4K score or MRI alone vs. both tests together for detecting csCaP. In addition, we evaluated several strategies using one or both tests for selecting men for biopsy and compared them based on the proportion of biopsies avoided and the csCaP's missed.

RESULTS

Among the 1,111 men who formed the final cohort, 553 (49.8%) had prostate cancer, and 353 (31.8%) had csCaP. We found that using MRI and 4K score together had better discrimination, calibration, and a higher clinical utility on decision curve analysis compared to using either test individually. Using both tests together resulted in fewer biopsies avoided and missed cancers compared to using either test alone. Strategies that sequence MRI and 4K score tests resulted in the largest biopsy reduction, with no appreciable difference between starting with an MRI vs. a biomarker.

CONCLUSIONS

We found that using both an MRI and 4K score together was superior to using either test alone but found no appreciable difference between starting with an MRI vs. starting with a 4K score. Prospective studies are needed to identify the best strategy to sequence MRI and biomarkers in the evaluation of csCaP.

Majority of men with premature ejaculation do not receive pharmacotherapy

Premature ejaculation is the most common male sexual dysfunction, with therapies including selective serotonin reuptake inhibitors, clomipramine, topical anesthetics, dapoxetine and tramadol. However, it is currently unknown how many men are receiving pharmacotherapy for premature ejaculation. Using the TriNetX Research network, a large multicenter database containing over 75 million patient records from hospitals across the United States, we evaluated prescribing patterns for treatment of premature ejaculation and assessed variations in prescription patterns among patients from 2015-2021. In addition, we examined if the prescription patterns for tramadol changed with the establishment of Prescription Drug Monitoring Programs. We found that most men (51.7%) were not receiving any pharmacotherapy for premature ejaculation. However, men with mental health disorders, were more likely (56.0%), to have been treated than those without (44.4%). On further analysis, men with mental health diagnoses were significantly more likely to be treated with Selective Serotonin Reuptake Inhibitors (45.0 vs 32.2%) and Tramadol (5.1% vs 3.5%). While the pharmacotherapy for premature ejaculation has been well researched, our findings revealed that most patients diagnosed with premature ejaculation do not receive pharmacotherapy and that patients are more likely to be prescribed premature ejaculation medications if they have a pre-existing mental health diagnosis.

Platelet-rich Plasma for the Treatment of Erectile Dysfunction: A Prospective, Randomized, Double-blind, Placebo-controlled Clinical Trial

PURPOSE

We assessed the safety and efficacy of 2 injections of platelet-rich plasma for treating mild to moderate erectile dysfunction by conducting a prospective, randomized, double-blind, placebo-controlled clinical trial.

MATERIALS AND METHODS

Men with mild to moderate erectile dysfunction (International Index of Erectile Function scores 11-25) were randomized to receive either 2 injections of platelet-rich plasma or placebo separated by 1 month. Primary outcome was percentage of men meeting minimum clinically important difference at 1 month after the second injection. Secondary outcomes were change in International Index of Erectile Function at 1, 3, and 6 months, and changes in penile vascular parameters and adverse events at 6 months.

RESULTS

We randomized 61 men: 28 into platelet-rich plasma and 33 into placebo. There was no difference between groups in percentage of men meeting minimum clinically important difference at 1 month: 14 (58.3%) in platelet-rich plasma vs 15 (53.6%) in placebo (P = .730). Mean International Index of Erectile Function-Erectile Function domain changed from 17.4 (95% CI 15.8-19.0) to 21 (17.9-24.0) at 1 month in men receiving platelet-rich plasma, vs 18.6 (17.3-19.8) to 21.6 (19.1-24.1) in the placebo group; however, there was no significant difference between groups (P = .756). There were no major adverse events and only 1 minor adverse event in each group. There were no changes in penile Doppler parameters from baseline to 6 months.

CONCLUSIONS

The results of our prospective, double-blind, randomized, placebo-controlled clinical trial suggest that 2 injections of intracavernosal platelet-rich plasma separated by 1 month in men with mild to moderate erectile dysfunction is safe, but we found no difference in efficacy between platelet-rich plasma and placebo.

A Case Report on "Pearling": Removal of Infected Objects During Circumcision

The insertion of foreign bodies underneath the skin of the penis is commonly referred to as "pearling." Although rare, there are case reports that describe acute complications such as infection and damage to surrounding penile neurovascular structures; however, there is a paucity of data describing long-term complications and surgical management of such cases. A 43-year-old male presented with a penile abscess secondary to "pearling" five years after insertion. His abscess was drained and selected foreign objects were subsequently removed during a simultaneous circumcision procedure. This report describes a case in which surgical removal of penile foreign bodies was performed during a circumcision without the need for additional incisions. The case is unique in that it details a complication five years after initial insertion with microbiological data to guide adequate treatment.

Prevalence of secondary erythrocytosis in men receiving testosterone therapy: A matched-cohort analysis of intranasal gel, injections, and pellets

INTRODUCTION

Increased hematocrit (HCT) is a common adverse effect in men on testosterone therapy (TTh). We aimed to uncover differences in HCT changes among men receiving different forms of TTh, namely intranasal gels, intramuscular injections, and subcutaneous pellets.

METHODS

We conducted a single-center, retrospective, matched-cohort study of patients treated for testosterone deficiency (TD) to investigate the effect of three TTh regimens on HCT. We included men who received intranasal testosterone (NT), intramuscular testosterone (TC), or subcutaneous testosterone pellet (TP) regimens between January 2011 and December 2020. We matched treatment cohorts 1:1:1 for age, body mass index (BMI), and history of obstructive sleep apnea. Those taking TTh for less than 16 weeks were excluded. Comparison between groups was performed with U-Mann Whitney test, Student t-test, ANOVA, or Kruskal Wallis test as appropriate.

RESULTS

Seventy-eight matched-cohort individuals with testosterone deficiency (TD) received either NT, TC, or TP. The most common TD symptoms prior to initiation of TTh were erectile dysfunction (38%), low libido (22%), and lack of energy (17%). Baseline serum testosterone and HCT were higher in NT (p<0.05) recipients. As expected, all men receiving TTh were found to have increased serum testosterone levels at followup (p<0.001). Relative to their respective baselines, men receiving TC experienced the greatest increase in serum testosterone (240.8 ng/dL to 585.5 ng/dL), followed by NT (230.3 ng/dL to 493.5 ng/dL) and TP (210.8 ng/dL to 360.5 ng/dL) (all p<0.001). TC and TP were associated with significant increases in HCT (4.4% and 1.7%), while NT was associated with a decrease in HCT (-0.8%) at 16-week followup.

CONCLUSIONS

When controlled for age, BMI, and OSA, men receiving NT experienced decreased HCT compared to TC or TP at 16-week followup. Intranasal testosterone, while able to increase serum testosterone levels to reference range, does not appear to have a significant impact on HCT compared to the longer-acting forms of TTh.

Comparison of Intratesticular Testosterone between Men Receiving Nasal, Intramuscular, and Subcutaneous Pellet Testosterone Therapy: Evaluation of Data from Two Single-Center Randomized Clinical Trials

PURPOSE

Testosterone replacement therapy (TRT) can potentially cause decreased spermatogenesis and subsequent infertility. Recent studies have suggested that 17-hydroxyprogesterone (17-OHP) is a reliable surrogate for intratesticular testosterone (ITT) that is essential for spermatogenesis. We evaluated data from two ongoing open-label, randomized, two-arm clinical trials amongst different treatment preparations (Trial I) subcutaneous testosterone pellets (TP) and (Trial II) intranasal testosterone (NT) or intramuscular testosterone cypionate (TC).

MATERIALS AND METHODS

Seventy-five symptomatic hypogonadal men (2 serum testosterone <300 ng/dL) were randomized into open label randomized clinical trials. Eligible subjects received 800 mg TP, 11 mg TID NT or 200 mg ×2 weeks TC. 17-OHP and Serum testosterone were evaluated at baseline and follow-up. The primary outcome was changes in 17-OHP. Secondary outcome was changes in serum testosterone. Data was analyzed by two-sample and single-sample t-tests, and determination of equal or unequal variances was computed using F-tests.

RESULTS

Median participant age was 45 years old, with overall baseline 17-OHP of 46 and serum testosterone of 223.5 ng/dL. 17-OHP significantly decreased in subjects prescribed long-acting TP or TC. The 4-month change in 17-OHP in the NT group (-33.3% from baseline) was less than the change seen in TC (-65.3% from baseline) or TP (-44% from baseline) (p=0.005). All testosterone formulations increased serum testosterone levels at follow-up, with the largest increase seen in TC (+157.6%), followed by NT (+114.3%) and TP (+79.6%) (p=0.005).

CONCLUSIONS

Short-acting nasal testosterone appear to have no impact on serum 17-OHP especially in comparison to long-acting testosterone formulations. All modalities saw significant increases in serum testosterone levels at follow-up. NT and other short acting testosterone formulations may better preserve ITT and be beneficial for hypogonadal men seeking to maintain fertility potential while on TRT.

A Phase 2 Randomized, Placebo-controlled Crossover Trial to Evaluate Safety and Efficacy of Platelet-rich Plasma Injections for Peyronie's Disease: Clinical Trial Update

Intralesional injection of platelet-rich plasma for Peyronie's disease appears to be safe according to early observations from an ongoing clinical trial. Efficacy data remain elusive until completion of the trial.

Collagenase Clostridium histolyticum Treatment Improves Degree of Curvature in Peyronie's Disease with Calcified Plaques

BACKGROUND

Peyronie's disease (PD) is a fibrotic condition of the penis characterized by abnormal plaque formation. Intralesional collagenase Clostridium histolyticum (CCh) is effective in noncalcified PD; however, its effectiveness in calcified PD is not well characterized.

OBJECTIVE

To assess curvature improvement in calcified PD plaques treated with CCh.

DESIGN, SETTING, AND PARTICIPANTS

We prospectively evaluated men with calcified PD electing CCh treatment at our institution from October 2018 to November 2020. We assessed curvature with artificial erection and goniometer before and at least 3 mo after treatment. We classified the type of plaque calcification based on ultrasound.

INTERVENTION

Intralesional CCh. Each treatment cycle consisted of two CCh injections (0.58 mg) into the plaque at the point of maximal penile curvature. The second injection was performed 72 h to 1 wk later, after which participants began modeling. All men were intended to receive a total of eight injections in four cycles, each 6 wk apart.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Change in penile curvature after CCh was measured. We assessed for differences in outcomes based on the number of injections and type of calcification. Unless otherwise specified, data are presented as medians (interquartile range).

RESULTS AND LIMITATIONS

Sixty men with calcified PD elected CCh; 47 had complete follow-up data. Thirty-nine men completed treatments with eight injections, while the remaining discontinued after a median of five (four to six) injections. There was no difference in response between type 2 and type 3 plaques. Curvature significantly improved by 17.5° (37.5-10.0°) in patients who completed treatment and by 15.0° (20.0-0.0°) in those who discontinued. Limitations include a small sample.

CONCLUSIONS

Men with calcified PD plaques improve with CCh treatment and show similar improvements regardless of calcification type.

PATIENT SUMMARY

In this study, we evaluated the efficacy of collagenase Clostridium histolyticum (CCh) treatment in calcified Peyronie's disease (PD) plaques. We found that treatment in calcified plaques demonstrated significant improvement in curvature and the grading of calcification did not impact the degree of curvature improvement. We conclude that participants with calcified PD plaques can benefit from nonsurgical CCh treatment.

Persistent Testosterone Suppression After Cessation of Androgen Deprivation Therapy for Prostate Cancer

Introduction Many men receiving temporary androgen deprivation therapy (ADT) for localized prostate cancer fail to achieve baseline testosterone levels after cessation. Testosterone recovery in men with localized prostate cancer receiving temporary ADT was assessed. Methods A global federated health research network (TriNetX) was used to identify men diagnosed with prostate cancer undergoing temporary ADT. Two cohorts were identified: men receiving luteinizing hormone-releasing hormone (LHRH) antagonists or LHRH agonists, and men receiving combined ADT (LHRH agonist and antiandrogens). Further stratification was based on a treatment duration of six months (short-term) or 18 months (long-term) to compare testosterone (T) recovery profiles five years after ADT cessation. Results A total of 28,583 men received LHRH agonist or antagonist therapy alone, and 20,188 men received combination ADT. A total of 46.7% of men who received short-term LHRH agonists or antagonists and 40.6% of men who received short-term combined ADT, recovered to mean baseline T levels at five years. Only men who received short-term LHRH agonists/antagonists recovered to eugonadal levels at the five-year follow-up. Around 50% of men who received long-term LHRH agonist/antagonist therapy and 10.7% of men who received combined ADT, recovered to mean baseline T levels at five years. However, neither group recovered to eugonadal T levels. Conclusions At the five-year follow-up after ADT cessation, most patients failed to recover to their mean baseline and eugonadal T levels. Given that testosterone deficiency is associated with metabolically adverse changes in body composition, increased insulin resistance, impaired bone health, and hypogonadal symptoms, serum T levels must be closely monitored in men receiving ADT following treatment cessation.

Cardiac sympathetic afferent denervation reduces matrix metalloproteinase expression and improves cardiac remodeling in rats post myocardial infarction

 

In a previous study from our laboratory, we demonstrated that chronic and selective cardiac sympathetic afferent (spinal) denervation at the time of myocardial infarction (MI) using epicardial application of resiniferatoxin (RTX), a neuronal toxin capable of inducing rapid degeneration of transient receptor potential vanilloid 1 (TRPV1)-expressing afferent neurons and fibers, markedly reduced the cardiac remodeling process 9–11 weeks post-MI in rats. This included reduced cardiac hypertrophy, fibrosis and apoptosis. Here, we further investigated the effect of epicardial application of RTX at the time of MI on cardiac extracellular matrix (ECM) and remodeling post-MI. Echocardiographic and morphologic data demonstrated that, compared to MI+vehicle, MI+RTX exhibited a significantly slower LV chamber dilation (6-week echocardiographic data: left ventricular end-diastolic diameter, 10.7±0.2 vs. 9.6±0.3 mm; left ventricular end-systolic diameter: 8.8±0.2 vs. 7.8±0.3 mm; MI+vehicle vs. MI+RTX, n=18, p&lt;0.05; mean±SE). Scanning electron microscopy showed that RTX reduced collagen deposition in the peri-infarct area in post-MI rats. Western blot and zymography were used to further evaluate the effect of RTX application on matrix metalloproteinase (MMP) expression and activity, which is responsible for degrading ECM and contributing to cardiac dilation post MI. Our data suggest time-dependent increases in MMP expression in infarcted hearts post MI. RTX application largely prevented the increase in MMP9 but not MMP2, 4 weeks post-MI. RTX prevented both increased MMP2 and MMP9 activities in the peri-infarct myocardium at 8–10 weeks post-MI. We further investigated the effect of RTX application on MI-induced cardiac inflammation, which has been reported as an upstream mechanism triggering MMP activation post-MI. The data show that RTX largely abolished MI-induced plasma extravasation and reduced macrophage infiltration and cardiac cytokine content in the peri-infarct or remote myocardium of post-MI rats. These data suggest that cardiac sympathetic afferent denervation at the time of MI exerts a local anti-inflammatory effect and reduces ECM remodeling by preventing excessive MMP activation in post-MI rats.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Institutes of Health Grant HL126796

Association Between MitoScore, BMI, and Body Fat Percentage as a Predictive Marker for the Outcome of In-Vitro Fertilization (IVF)

Background

Infertility is defined as the inability to establish a pregnancy within 12 months of regular and unprotected sexual intercourse. In response to these problems, assisted reproductive techniques (ARTs) have made profound impacts on the therapeutic management of infertility. However, in-vitro fertilization (IVF) success rates are confounded by several internal and external factors. A relatively new approach to embryo assessment is known as MitoScore (Igenomix, Miami, USA). As a result, we sough to evaluate whether MitoScore can help in predicting in IVF outcomes, and to assess the relationship between MitoScore, BMI, and body fat percentage in determining the success of ARTs.

Methods

Using retrospective cohort, a study population consisting of 166 women aged 26-43 who were undergoing ART with pre-implantation genetic testing for aneuploidy (PGT-A) was assessed to determine if MitoScore, BMI, and body fat percentage impacted IVF outcomes.

Results

MitoScore, BMI, and body fat percentage were significantly lower in pregnant women as compared to non-pregnant women. Furthermore, MitoScore was correlated with subclasses of IVF outcomes (delivery, biochemical pregnancy, and spontaneous abortion) and was found to be positively correlated with BMI in patients with biochemical pregnancies.

Conclusion

Our findings suggest that MitoScore, BMI, and body fat percentage could act as critical parameters in determining the success of ART. However, the association between MitoScore, BMI, and body fat percentage does not appear to be a significant confounding factor to determine pregnancy outcome at this stage. Still, many factors need to be considered to establish the correlation reliably.

Racial and Ethnic Inequality in Survival Outcomes of Women With Triple Negative Breast Cancer

Purpose

Triple-negative breast cancer (TNBC) is the most lethal group of breast cancers. Socioeconomic factors may contribute to differences in survival rates. This study aims to identify racial/ethnic disparities in five-year survival rates among women affected by TNBC in the United States.

Methods

This retrospective study analyzed data from the 2010-2016 Surveillance, Epidemiology, and End Results Program database. Patients with a primary malignancy of triple-negative breast cancer were included in this study. Cancer-specific survival was measured at five years post-diagnosis. Cox regression models were used to calculate hazard ratios (HR) and corresponding 95% confidence intervals (CI).

Results

From 2010-2016, there were 26,963 women with a primary diagnosis of TNBC. After adjustment for age, insurance, marital status, stage, and surgery type, Hispanic women had the highest hazard of death when compared to White women (adjusted (adj) HR, 1.14, p<0.001). Further, non-Hispanic Black women also had a lower survival probability when compared to White women (adj HR, 1.06, p=0.002).

Conclusion

This study reveals that Hispanic women had the highest hazard of death when compared to White women. As TNBC is the most fatal breast cancer, future studies should investigate socioeconomic factors that may worsen prognosis of this disease.

The Safety of Human Chorionic Gonadotropin Monotherapy Among Men With Previous Exogenous Testosterone Use

Background and objective

Human chorionic gonadotropin (hCG) is homologous to luteinizing hormone (LH) and stimulates endogenous testosterone (T) production. Current American Urological Association (AUA) guidelines recommend hCG for T-deficient men who wish to preserve their fertility. However, there is no data available regarding the long-term efficacy and safety of hCG monotherapy in men with a history of exogenous T use. We hypothesized that transitioning to hCG would be a safe and effective option in this population.

Methodology

We performed a retrospective analysis involving 28 men with previous exogenous T use who were switched to hCG monotherapy and underwent follow-up lab work at least one month later. We evaluated changes in hormones [T, LH, follicle-stimulating hormone (FSH), and estradiol], hematocrit (HCT), glycated hemoglobin (HbA1c), and prostate-specific antigen (PSA).

Results

Among the entire cohort, we found no significant change in mean hormone levels (including T), HbA1c, or PSA. There was a significant (p<0.05) decrease in HCT (45.27 ±4.06 to 44.16 ±3.48%, n=15). No thromboembolic events were reported. Additionally, among men who had their baseline labs completed outside their previous T therapy therapeutic time window prior to starting hCG monotherapy, there was a statistically significant increase in mean T levels (307.36 ±148.74 to 422.11 ±268.15 ng/dL, n=30 and 31, pre- and post-hCG, respectively) and a statistically significant decrease in mean PSA levels (0.91 ±0.35 to 0.69 ±0.23 ng/mL, n=5).

Conclusions

These results suggest that hCG is a safe and effective alternative to traditional T therapy for men with a history of exogenous T use and may lead to an advantageous decrease in HCT. hCG may serve as an alternative form of T therapy with a lower risk for secondary erythrocytosis, and further research is warranted to gain deeper insights into the topic.

Efficacy and Safety of Human Chorionic Gonadotropin Monotherapy for Men With Hypogonadal Symptoms and Normal Testosterone

Background

Male hypogonadism has a prevalence of about 6% and is defined by two-morning testosterone levels below 300 ng/dl associated with symptoms. This definition presents a challenging problem for patients without other medical problems but with symptoms of low testosterone (T) who do not meet the biochemical criteria for therapy.

Objectives

Our objective was to evaluate changes in symptoms and side effects in men with T levels >300ng/dL using human chorionic gonadotropin (hCG) monotherapy for the treatment of hypogonadal symptoms.

Methods

After IRB approval, 31 male patients treated with hCG monotherapy for low T symptoms were retrospectively reviewed. We evaluated changes in hormones, hypogonadal symptoms, and the incidence of thromboembolic events before and after starting hCG.

Results

We found subjective improvement in erectile dysfunction, 86% (19/22), and libido, 80% (20/25), with no patient experiencing a thromboembolic event. In addition, no change was observed in the follicle-stimulating hormone, luteinizing hormone, estradiol, hematocrit, hemoglobin A1c, and prostate-specific antigen.

Conclusion

Weekly treatment with hCG appears safe and can improve hypogonadal symptoms in patients with T >300 ng/dl without changes to hematocrit, prostate-specific antigen, and hemoglobin A1c.

Do Women Have a Seat at the Table: Trends in Female Representation Among the Board of Directors in American Urological Association Subspecialty Societies

Introduction

Although women remain vastly underrepresented in urology, the proportion of female urology residents and practicing urologists has steadily increased over the last four decades. However, it remains critical to evaluate the representation of females in the pipeline when examining trainees and practicing urologists. As it pertains to leadership positions, the gender distribution among the board of directors (BOD) and committee chairs in the American Urological Association (AUA) subspecialties has not been studied to date. Therefore, we plan to analyze the proportion of females among the BOD and committee chairs in different subspecialty societies recognized by the AUA over time.

Methods

We conducted a cross-sectional observational study, quantitatively comparing the composition of gender in BOD and Committee Chair members belonging to different AUA-recognized subspecialty societies from 2014 to 2020. The websites for each subspecialty society were searched and contacted.

Results

We evaluated BODs from 10 AUA subspecialty societies and committee chair members from 6 AUA subspecialty societies. From 2014 to 2020, the total proportion of female BOD amongst all AUA sub-specialty societies did not change significantly, with a small increase from 10.6% (n = 29) to 13.5% (n = 36). However, female representation among committee chair members significantly increased from 9.8% (n = 20) to 19.2% (n = 44; p = 0.006), along with the total number of women in urology, from 897 (8.9%) to 1,375 (10.3%). Increases in female representation were seen in the Society for the Study of Male Reproduction (SSMR) from 0% to 9% and in the Indian American Urological Association (IAUA) from 4% to 13%. Of note, there were no elected female board members in the Society of Urologic Oncology (SUO) or the Urologic Society for Transplantation and Renal Surgery (USTRS) from 2014 to 2020.

Conclusion

Females remain a minority in leadership positions at AUA sub-specialty societies despite increased female representation in recent years. Future efforts should promote the advancement of women to positions of leadership to reflect the changing landscape of the urology workforce and surgical specialties.

Smoking as a Risk Factor for Surgical Site Complications in Implant-Based Breast Surgery

Background Smoking is a cause of many postoperative complications, including delayed wound healing, tissue necrosis, and reconstructive flap loss. However, there is a paucity of evidence-based guidelines for smoking cessation in patients undergoing implant-based breast surgery. Objective The objective of this study was to determine if smoking is associated with wound dehiscence or superficial/deep surgical site infection (SSI) in women undergoing implant-based breast surgery. Methods Using theAmerican College of Surgeons National Surgical Quality Improvement Program, data was obtained of U.S. adult females (n=10,077) between the ages of 18 and 70 who underwent insertion of a breast prosthesis from 2014 to 2016. The patient's preoperative smoking status, demographics, and comorbidities were analyzed to determine association with wound dehiscence, superficial SSI, and deep SSI. Unadjusted and adjusted logistic regression analyses were used to calculate odds ratios (OR) and 95% confidence intervals (95% CI). Results Patients who smoked had a statistically significant higher proportion of wound complications (2.4%) compared to non-smokers (1.3%; p<0.01). Adjusted analysis demonstrated a significantly higher odds of wound complications in smoking patients compared to those who did not smoke (OR 2.0; 95% CI 1.3-3.2). Conclusions Our study suggests that smoking is an independent risk factor for postoperative complications in patients undergoing implant-based breast surgery. These results have significant clinical implications, as increased precautions can be taken in smokers undergoing breast surgery to minimize postoperative wound complications. Future studies may determine the optimal amount of time that patients should abstain from smoking prior to implant-based breast surgery.

Prevalence of diabetes among children treated with growth hormone in Israel

AIMS

To determine the long-term risk of diabetes in a cohort of children treated with recombinant human growth hormone in Israel, using data from the Israeli National Diabetes Register.

METHODS

Between 1988 and 2009, 2513 children were approved for growth hormone treatment. They were assigned to one of two groups. The first group included children treated for isolated growth hormone deficiency and who were small for gestational age and the second included those treated for multiple pituitary hormone deficiency, chronic renal failure, Turner syndrome or Prader-Willi syndrome. The cohort was cross-linked with the Israeli National Diabetes Register for 2014 (mean follow-up duration 12.1±5.3 years), and prevalent cases of diabetes were identified. Standardized prevalence ratios for diabetes were calculated for people aged 10-29 years.

RESULTS

In 2014, a total of 23 individuals were identified with diabetes (four with pre-existing diabetes, seven developed diabetes before age 17 years and 12 developed it at a later age). In the isolated growth hormone deficiency and small-for-gestational-age group there was no difference in the prevalence of diabetes compared with the general population (standardized prevalence ratio 2.05, 95% CI 0.94-3.89). In the group that included people with multiple pituitary hormone deficiency, chronic renal failure, Turner syndrome and Prader-Willi syndrome there was a significantly higher diabetes prevalence (standardized prevalence ratio 11.94, 95% CI 6.53-20.00) compared with the general population.

CONCLUSIONS

No difference in diabetes prevalence was found in the isolated growth hormone deficiency and small-for-gestational-age group, compared with the general population. Children treated with growth hormone with pre-existing risk factors had an increased prevalence of diabetes. It is advisable to monitor blood glucose levels closely during and after growth hormone treatment, especially in such children.

A hybrid process of biofiltration of secondary effluent followed by ozonation and short soil aquifer treatment for water reuse

The Shafdan reclamation project facility (Tel Aviv, Israel) practices soil aquifer treatment (SAT) of secondary effluent with hydraulic retention times (HRTs) of a few months to a year for unrestricted agricultural irrigation. During the SAT, the high oxygen demand (>40 mg L(-1)) of the infiltrated effluent causes anoxic conditions and mobilization of dissolved manganese from the soil. An additional emerging problem is the occurrence of persistent trace organic compounds (TrOCs) in reclaimed water that should be removed prior to reuse. An innovative hybrid process based on biofiltration, ozonation and short SAT with ∼22 d HRT is proposed for treatment of the Shafdan secondary effluent to overcome limitations of the existing system and to reduce the SAT's physical footprint. Besides efficient removal of particulate matter to minimize clogging, coagulation/flocculation and filtration (5-6 m h(-1)) operated with the addition of hydrogen peroxide as an oxygen source efficiently removed dissolved organic carbon (DOC, to 17-22%), ammonium and nitrite. This resulted in reduced effluent oxygen demand during infiltration and oxidant (ozone) demand during ozonation by 23 mg L(-1) and 1.5 mg L(-1), respectively. Ozonation (1.0-1.2 mg O3 mg DOC(-1)) efficiently reduced concentrations of persistent TrOCs and supplied sufficient dissolved oxygen (>30 mg L(-1)) for fully oxic operation of the short SAT with negligible Mn(2+) mobilization (<50 μg L(-1)). Overall, the examined hybrid process provided DOC reduction of 88% to a value of 1.2 mg L(-1), similar to conventional SAT, while improving the removal of TrOCs and efficiently preventing manganese dissolution.

Oxytocin and same-sex social behavior in female meadow voles

The neuropeptide oxytocin (OT) has been implicated in a range of mammalian reproductive and social behaviors including parent-offspring bonding and partner preference formation between socially monogamous mates. Its role in mediating non-reproductive social relationships in rodents, however, remains largely unexplored. We examined whether OT facilitates same-sex social preferences between female meadow voles-a species that forms social nesting groups in short, winter-like day lengths. In contrast to results from studies of opposite-sex attachment between prairie vole mates, we found that neither OT nor dopamine neurotransmission was required for baseline levels of social partner preference formation or expression. OT enhanced preference formation beyond baseline levels-an effect that was counteracted by treatment with an oxytocin receptor antagonist (OTA). Oxytocin receptor (OTR) density correlated with social behavior in brain regions not known to be associated with opposite-sex affiliation, including the lateral septum and central amygdala. In addition, voles housed in short day lengths (SD) exhibited higher levels of OTR binding in the central amygdala, and voles exposed to high concentrations of estradiol exhibited less binding in the nucleus accumbens (NAcc) and increased binding in the ventromedial nucleus of the hypothalamus. These results suggest that same-sex social behavior shares common elements with other mammalian social behaviors affected by OT, but that the specific neural pathways through which OT exerts its influence are likely distinct from those known for sexual attachments.

Perinatal influences of melatonin on testicular development and photoperiodic memory in Siberian hamsters

We assessed the influence of perinatal melatonin on reproductive development and adult responsiveness to melatonin. Testicular growth in an intermediate day length (14 : 10 h light/dark cycle) was substantially reduced in Siberian hamsters gestated by pinealectomised compared to pineal-intact females; gonadal development was normalised in offspring of pinealectomised dams that were pinealectomised at 3-4 days of age. Hamsters deprived of melatonin only during gestation, or both pre- and postnatally, underwent testicular involution during treatment with melatonin in adulthood. Photoperiodic histories acquired prenatally did not endure as long as those acquired by adult hamsters. Hamsters first exposed to melatonin in adulthood were not more proficient in acquiring photoperiodic histories than were normal males. These findings indicate that pre- versus postnatal differences in melatonin signal duration determine rates of testicular development. Exposure to melatonin perinatally does not appear to organise the neuroendocrine substrate that mediates effects of day length and melatonin on the gonads of adult hamsters.

Seasonal control of penile development of Siberian hamsters (Phodopus sungorus) by daylength and testicular hormones

Seasonal variation in prepubertal penile growth has not previously been studied. The present study assessed the influence of daylength and androgens on penile development in the Siberian hamster (Phodopus sungorus). Adult penile masses were achieved at 18 and 8 weeks of age in hamsters maintained from birth under short (10 h light:14 h dark) versus long (14 h light:10 h dark) daylengths, respectively. Insulin-like growth factor I concentrations, previously implicated in penile growth, did not differ between hamsters maintained in short versus long daylengths. Gonadectomized juvenile males maintained in short and long daylengths and administered testosterone attained adult penile masses well in advance of untreated gonad-intact males maintained in short daylengths. Hamsters from both photoperiods, castrated as juveniles and first treated with testosterone in adulthood, also achieved adult penile masses. The photoinhibited gonad is insufficient to promote penile growth, and prepubertal gonadal secretions during short daylengths are not necessary for eventual penile development. Among young born near the end of the mating season, onset of neuroendocrine refractoriness to short daylengths at about 100 days of age and subsequent gonadal development induces growth in all reproductive tissues. Timing of puberty and increased androgen secretion controlled by daylength are the primary determinants of postnatal penile growth, which may also be affected by prenatal and early postnatal organizational actions of androgens.

Termination of neuroendocrine refractoriness to melatonin in Siberian hamsters (Phodopus sungorus)

Siberian hamsters maintained from birth in a short day length (DL), unlike their long-day counterparts, fail to undergo reproductive development by 5 weeks of age. Instead, reproductive maturation of short-day males is delayed for approximately 20 weeks, at which point neuroendocrine refractoriness to the inhibitory effects of short DLs develops, resulting in growth of the gonads. To terminate refractoriness and re-establish responsiveness to short photoperiods, 10-15 weeks of long-day exposure is required. We assessed whether continuous exposure to long days is necessary to terminate refractoriness or whether the first few weeks of long days initiate a process that culminates several months later in the breaking of refractoriness. Male hamsters refractory to short DLs were transferred to a long-day photoperiod, pinealectomized (PINx) after 0, 3, 6 or 15 weeks, and subsequently infused for 6 weeks with a short-day melatonin signal. This melatonin treatment induces gonadal regression in photosensitive but not in photorefractory hamsters. Six percent of males PINx at week 0 and 88% of those PINx at week 15 underwent gonadal atrophy by the end of the melatonin infusion treatment initiated on week 15. Among hamsters PINx on week 6, 17% versus 76% underwent testicular involution in response to melatonin infusions initiated on week 6 and week 15, respectively. This finding indicates that a fraction of the long days that hamsters experience during spring and summer are sufficient to trigger the processes that restore responsiveness to short DLs. Additional groups of pineal-intact photorefractory animals were given 3, 6 or 15 weeks of long-day exposure and then returned to a short DL for several months; only those treated for 15 weeks terminated refractoriness. The breaking of refractoriness, once triggered by long-day melatonin signals, proceeds to completion only in the absence of short-day melatonin signals.

Photoperiodic control of oestrous cycles in Syrian hamsters: mediation by the mediobasal hypothalamus

To assess whether the mediobasal hypothalamus (MBH) is necessary for photoperiodic control of oestrous cycles and prolactin secretion, we tested intact female Syrian hamsters (controls) and those that had sustained unilateral or bilateral lesions of the MBH. All hamsters displayed 4-day oestrous cycles postoperatively in the long-day photoperiod (14 h light/day); control females and those with unilateral MBH damage ceased to undergo oestrous cycles approximately 8 weeks after transfer to a short-day photocycle (10 h light/day), whereas 12 of 15 females with bilateral MBH lesions continued to generate 4-day oestrous cycles throughout 22 weeks in short days. Serum prolactin concentrations were either undetectable or low in all hamsters 8 or 14 weeks after the transfer to short-day lengths, but increased above long-day baseline values by week 22. We conclude that melatonin-binding sites in the MBH mediate suppression of oestrous cycles but not prolactin secretion by short-day lengths; recovery of prolactin secretion in females during prolonged exposure to short-day lengths reflects development of refractoriness to melatonin in a substrate distinct from the MBH. These findings suggest that separate neural pathways mediate photoperiodic control of gonadotropin and prolactin secretion in female hamsters.

Itch characteristics in Chinese patients with atopic dermatitis using a new questionnaire for the assessment of pruritus

BACKGROUND

Although pruritus is the predominant and commonest feature of atopic dermatitis, its clinical characteristics have not been explored.

OBJECTIVE

To characterize the clinical pattern and sensory and affective dimensions of the itch experience utilizing a comprehensive itch questionnaire.

METHODS

A structured itch questionnaire based on the McGill pain questionnaire was given to 102 Chinese patients with known atopic dermatitis.

RESULTS

There were 100 patients with atopic dermatitis who fully filled the questionnaire. In 87% of the patients pruritus appeared on a daily basis. It had a prolonged duration (mean duration 10.7 7.3 years). It involved all body areas mostly in the lower limbs (83%), flexures (76%), upper limbs (71%) and neck (65%). Itch intensity during its peak was nearly twice higher than the itch of a mosquito bite. Itching was most frequent at night (65%), and 84% of patients reported of difficulty falling asleep. Daily life activities which increased the severity of itch were sweat in 96%, dryness in 71%, stress in 71% and physical effort in 73%. The major factors which were found to reduce the intensity of pruritus included: bathing with cold water in 55% and cold ambient environment in 56%. Associated symptoms were heat sensation (51%), sweating (40%) and pain in the pruritic area (45%). The various anti-pruritic therapies had limited long-term effect. The pruritus was bothersome (52%) and a major distress to the patient. The affective score correlated to itch intensity during its peak (r = 0.4, P < 0.001).

CONCLUSIONS

The study provided a detailed description of pruritus in atopic dermatitis with new data on affective and sensory dimensions and associated symptoms. The questionnaire was found to be a useful tool in characterization of itch.

Torpor characteristics and energy requirements of furless Siberian hamsters

After approximately 10 wk of exposure to decreasing day lengths, Siberian hamsters (Phodopus sungorus) begin to display spontaneous torpor bouts several times each week. Torpor is associated with reduced daily energy expenditure and lower food consumption and ameliorates the thermoregulatory challenges of winter. We tested the extent to which the energy savings conferred by daily torpor depend on the presence of an insulative pelage. Female hamsters were housed in a winter day length (8L:16D) at 5 degrees C; daily food intake and torpor characteristics were recorded for 5 wk in shaved (furless) or normal hamsters. Torpor-bout incidence decreased by 62% in furless hamsters, but the duration of individual bouts and the minimum body temperature attained during torpor were unaffected by loss of pelage. Body temperature declined more rapidly during entry into torpor and increased more slowly during arousal from torpor in furless than in control hamsters. Energy savings per torpor bout, assessed by the amount of food consumed on days that included a torpor bout, was substantially greater in normal than in furless hamsters (16.0% vs. 3.3%); this difference likely reflects the increased cost of thermoregulation during torpor, as well as the increased caloric expenditure incurred by furless hamsters during arousal from torpor. An insulative pelage may be a prerequisite for the energetic benefits derived from heterothermy in this species.

Energy intake and fur in summer- and winter-acclimated Siberian hamsters (Phodopus sungorus)

Few studies have directly addressed the impact of fur on seasonal changes in energy intake. The daily food intake of Siberian hamsters (Phodopus sungorus) was measured under simulated summer and winter conditions in intact animals and those with varying amounts of pelage removed. Energy intake increased up to 44% above baseline control values for approximately 2-3 wk after complete shaving. Increases in food intake varied with condition and were greater in hamsters housed in short than long day lengths and at low (5 degrees C) than moderate (23 degrees C) ambient temperatures. Removal of 8 cm(2) of dorsal fur, equivalent to 30% of the total dorsal fur surface, increased food intake, but removal of 4 cm(2) had no effect. An 8-cm(2) fur extirpation from the ventral surface did not increase food consumption. Food intake was not influenced differentially by fur removal from above brown adipose tissue hot spots. Fur plays a greater role in energy balance in winter- than summer-acclimated hamsters and conserves energy under a wide range of environmental conditions.

Refractoriness to melatonin occurs independently at multiple brain sites in Siberian hamsters

The mid-winter development of refractoriness to melatonin (Mel) triggers recrudescence of the atrophied reproductive apparatus of rodents. As a consequence, over-wintering animals become reproductively competent just before the onset of spring conditions favorable for breeding. The neural target tissues that cease to respond to winter Mel signals have not been identified. We now report that the suprachiasmatic nucleus of the hypothalamus, which contains the principal circadian clock, and the reuniens and paraventricular nuclei of the thalamus, each independently becomes refractory to melatonin. Small implants of Mel that were left in place for 40 wk and that act locally on these brain nuclei, induced testicular regression within 6 wk in male Siberian hamsters; 12 wk later Mel implants no longer suppressed reproduction and gonadal recrudescence ensued. Hamsters that were then given a systemic Mel infusion s.c. immediately initiated a second gonadal regression, implying that neurons at each site become refractory to Mel without compromising responsiveness of other Mel target tissues. Refractoriness occurs locally and independently at each neural target tissue, rather than in a separate "refractoriness" substrate. Restricted, target-specific actions of Mel are consistent with the independent regulation by day length of the several behavioral and physiological traits that vary seasonally in mammals.

A questionnaire for the assessment of pruritus: validation in uremic patients

A questionnaire was constructed for the evaluation and measurement of pruritus. The questionnaire, based on the short form of the McGill Pain Questionnaire, was tested in 145 patients suffering from uremic pruritus and currently undergoing hemodialysis treatment in 3 centers. The newly developed questionnaire proved to be reliable and provided valid data on the sensory, affective and overall intensity of uremic pruritus. The data suggest that uremic pruritus tends to be prolonged, frequently intense and a major source of distress to the patient. Dialysis was not found to influence the pruritus. The questionnaire may also be useful in pruritus secondary to other causes.

Low ambient temperature accelerates short-day responses in Siberian hamsters by altering responsiveness to melatonin

Exposure to low ambient temperatures (Ta) accelerates appearance of the winter phenotype in Siberian hamsters transferred from long to short day lengths. Because melatonin transduces the effects of day length on the neuroendocrine axis, the authors assessed whether low Ta promotes the transition to winterlike traits by accelerating the onset of increased nocturnal melatonin secretion or by enhancing responsiveness to melatonin in short day lengths. Male hamsters were transferred from 16L (16 h light/day) to 8L (8 h light/day) photoperiods and held at 5 degrees C or 22 degrees C. Locomotor activity was recorded continuously, and body mass, testis size, and pelage color were determined biweekly for 8 weeks. The duration of nocturnal locomotion (alpha), a reliable indicator of the duration of nocturnal melatonin secretion, lengthened significantly earlier in hamsters exposed to a Ta of 5 degrees C than 22 degrees C. Cold exposure increased the proportion of hamsters that were photoresponsive: gonadal regression in short days increased from 44% at 22 degrees C to 81% at 5 degrees C (p < 0.05); low Ta did not, however, accelerate testicular regression in animals that were photoresponsive. Nonphotoresponsive animals at 5 degrees C temporarily had longer alphas during the first 4 weeks in short days and significant decreases in body mass and testicular size that were reversed during the ensuing weeks when alpha decreased. In a 2nd experiment, pinealectomized male hamsters infused for 10 h/day with melatonin for 2 weeks had significantly lower body and testes masses when maintained at 5 degrees C but not 22 degrees C. Low-ambient temperature appears to accelerate the appearance of the winter phenotype primarily by increasing target tissue responsiveness to melatonin and to a lesser extent by augmenting the rate at which the duration of nocturnal melatonin secretion increases in short day lengths.

Testicular development in Siberian hamsters depends on frequency and pattern of melatonin signals

We investigated the impact of frequency and pattern of melatonin signals on reproductive development in Siberian hamsters. Juvenile males gestated in short day lengths and housed in constant illumination to suppress melatonin secretion were infused with melatonin for 5 h either once or twice per day for 20 days. Melatonin infusions at either frequency produced equivalent increases in testes and body weights that exceeded those of animals infused with saline but were indistinguishable from those of hamsters transferred to long day lengths. The reproductive system appears to be maximally stimulated by a single short melatonin signal each day. Other animals kept from birth in a short photoperiod were treated 6 h after onset of darkness with the beta-adrenergic receptor antagonist DL-propranolol to shorten melatonin secretion on the night of injection but not on subsequent nights. This permitted interpolation of short nightly melatonin signals of 4-5 h duration against a background of long melatonin signals of 10-12 h duration on other nights. Treatment regimes that maintained a 1:1 ratio of short to long melatonin signals for 8 wk stimulated reproductive development; a 1:2 signal ratio, in each of three different patterns, was uniformly ineffective. The number of successive short melatonin signals had little influence on the interval across which successive melatonin signals were summated to influence photoperiodic traits. The neuroendocrine axis appears more responsive to short melatonin signal frequency than pattern for development of the summer phenotype.

Temperature-independence of circannual variations in circadian rhythms of golden-mantled ground squirrels

In golden-mantled ground squirrels, phase angles of entrainment of circadian locomotor activity to a fixed light-dark cycle differ markedly between subjective summer and winter. A change in ambient temperature affects entrainment only during subjective winter when it also produces pronounced effects on body temperature (Tb). It was previously proposed that variations in Tb are causally related to the circannual rhythm in circadian entrainment. To test this hypothesis, wheel-running activity and Tb were monitored for 12 to 14 months in castrated male ground squirrels housed in a 14:10 LD photocycle at 21 degrees C. Animals were treated with testosterone implants that eliminated hibernation and prevented the marked winter decline in Tb; these squirrels manifested circannual changes in circadian entrainment indistinguishable from those of untreated animals. Both groups exhibited pronounced changes in phase angle and alpha of circadian wheel-running and Tb rhythms. Seasonal variation in Tb is not necessary for circannual changes in circadian organization of golden-mantled ground squirrels.

Role of area postrema in control of torpor in Siberian hamsters

Siberian hamsters undergo torpor during the short days of winter and in response to glucoprivation or food restriction. We tested whether the area postrema and the adjacent nucleus of the solitary tract (hereafter the AP), which monitor metabolic fuel availability, also control the onset of torpor. Siberian hamsters that had manifested torpor spontaneously or had entered torpor in response to 2-deoxy-D-glucose (2-DG) treatment were subjected to area postrema ablations (APx). Hamsters continued to display torpor postoperatively; most features of torpor were unaffected by APx. The AP is not necessary for expression of torpor elicited by short day lengths or metabolic challenge. In contrast, decreases in food intake manifested by hamsters treated with 2-DG were counteracted by APx. In Siberian hamsters, the AP appears to mediate effects of 2-DG on food intake but not torpor.

Establishment and persistence of photoperiodic memory in hamsters

Long summer days unequivocally stimulate, and short winter days inhibit reproduction in Siberian hamsters. By contrast, intermediate-duration day lengths (12.5-14 h long) either accelerate reproductive development or initiate regression of the reproductive apparatus. Which of these outcomes transpires depends on an animal's photoperiodic history, suggesting that hamsters must encode a representation of prior photoperiods. The duration of nocturnal melatonin secretion is the endocrine representation of day length, but nothing is known about how long it takes to establish photoperiodic histories or how long they endure. Hamsters exposed for 2 or more weeks to long summer day lengths acquired a long-day photoperiodic history that determined subsequent reproductive responses to intermediate-duration day lengths and melatonin signals. The memory for long-day lengths persisted in pinealectomized hamsters for 6.5 weeks, faded significantly after 13 weeks, and was functionally absent after 20 weeks. These findings indicate that hamsters are influenced only by relatively recent day lengths and melatonin signals and ignore earlier ones that might cause them to misinterpret the salience of current day lengths.

Photic entrainment of circannual rhythms in golden-mantled ground squirrels: role of the pineal gland

Entrainment of circannual rhythms of body mass and reproduction was monitored for 3 years in female golden-mantled ground squirrels maintained in a simulated natural photoperiod. Both pinealectomized and pineal-intact squirrels generated circannual rhythms of body mass and estrus, but only the intact animals entrained these rhythms to a period of 365 days. In the second and third years after treatment, the period of the body mass rhythm was significantly shorter than 365 days for pinealectomized squirrels, and variance in tau among these animals was significantly greater than for intact squirrels. A similar pattern was evident in the rhythm of reproduction, which was phase-disrupted in pinealectomized squirrels but entrained in intacts. Seasonal changes in duration of nocturnal melatonin secretion by the pineal appear to be necessary to produce phase-delays required to entrain the circannual clock to a period of 12 months.

Triggering of neuroendocrine refractoriness to short-day patterns of melatonin in Siberian hamsters

Short day lengths induce gonadal regression within 6 weeks in Siberian hamsters, but this inhibitory effect eventually wanes and reproductive competence is regained after 4-6 months in short days. These experiments were undertaken to determine whether continuous exposure to short days for several months is necessary to induce neuroendocrine refractoriness, or if a few weeks of short days are sufficient to trigger processes that culminate in refractoriness several months later. Adult male Siberian hamsters transferred from their natal long-day photoperiod of 15L (15 h light/day) to a short-day photoperiod of 10L were pinealectomized (PINx) after 0, 6, 12, 21 or 40 weeks of exposure to 10L. Intact hamsters kept in 10L manifested gonadal regression by week 6 and completed gonadal recrudescence by week 40, at which time they too were PINx. Beginning at week 40 all hamsters were infused s.c. with melatonin for 10 h/day for 6 consecutive weeks. This treatment induces gonadal regression in photosensitive hamsters. At the end of melatonin treatment, maximal gonadal regression was recorded for hamsters PINx at week 0 and those PINx after 40 weeks in long days. Hamsters PINx after 40 week of short day treatment were completely unresponsive to melatonin whereas those PINx after 6 and 12 weeks had intermediate responses. The percentage of hamsters whose reproductive apparatus was refractory to melatonin at week 40 increased with increasing duration of exposure to short days prior to PINx. Refractoriness was induced by relatively few weeks of short days in some hamsters, whereas others required much more extensive exposure. Induction of refractoriness is triggered by a fraction of the short days that hamsters experience in nature but may not be manifested until many weeks later when it coincides with gonadal recrudescence. In nature all hamsters are exposed to short days for at least 25 weeks, ensuring refractoriness in most individuals.

Ventromedial hypothalamic mediation of photoperiodic gonadal responses in male Syrian hamsters

Short day lengths induce testicular regression in seasonally breeding Syrian hamsters. To test whether the ventromedial hypothalamus is necessary to maintain reproductive quiescence once testicular regression has been achieved, photoregressed male hamsters were subjected to lesions of the ventromedial hypothalamus (VMHx), pinealectomy (Pinx), or sham operation (Sham). VMHx hamsters underwent accelerated gonadal recrudescence compared to Pinx and Sham hamsters. Recovery of prolactin concentrations (PRL) to values characteristic of long-day hamsters was hastened in the VMHx animals compared to Sham hamsters. Concentrations of follicle stimulating hormone (FSH) increased prematurely in both the VMHx and Pinx animals, beginning a few weeks after surgery. By the time the gonads had undergone recrudescence and the hamsters were refractory to melatonin, PRL and FSH concentrations had returned to baseline long-day values in all groups; there was no evidence of hypersecretion of either hormone in any of the animals with lesions. Melatonin concentrations of VMHx hamsters did not differ from those of sham-operated animals, but because only a single determination was made, it remains possible that VMH damage altered the duration of nightly melatonin secretion. An intact VMH appears to be essential for the continued maintenance of reproductive suppression induced by exposure to short day lengths; these and earlier findings suggest that the VMH-dorsomedial hypothalamic complex mediates regression of the reproductive apparatus during decreasing day lengths of late summer and early autumn and also is necessary to sustain regression during the winter months.

Photoperiod modulates torpor and food intake in Siberian hamsters challenged with metabolic inhibitors

Siberian hamsters, Phodopus sungorus, exposed to a short photoperiod (SP) were challenged with 2-deoxy-D-glucose (2DG), which disrupts glycolysis and induces torpor in animals maintained in long photoperiods (LP), or mercaptoacetate (MA), which disrupts fatty acid oxidation. SP decreased rather than facilitated the induction of torpor by 2DG; decreased torpor in response to 2DG coincided with onset of spontaneous torpor in SP hamsters. In contrast, MA induced hypothermia in hamsters kept in SP but not LP, but did not induce full torpor. We conclude that short day lengths do not induce spontaneous torpor by increasing responsiveness to glucose availability; instead, responsiveness to glucoprivation is, if anything, blunted in SP. The occurrence of spontaneous torpor may be unrelated to concurrent metabolic fuel availability. Although 2DG and MA had different effects on thermoregulation in short vs. long day lengths, each treatment decreased 24-h food intake in hamsters in both photoperiods.

Hypoglycemia and torpor in Siberian hamsters

We tested whether reduced blood glucose concentrations are necessary and sufficient for initiation of torpor in Siberian hamsters. During spontaneous torpor bouts, body temperature (Tb) decreases from the euthermic value of 37 to <31 degrees C. Among hamsters that displayed torpor during maintenance in a short-day length (10 h light/day) at an air temperature of 15 degrees C, blood glucose concentrations decreased significantly by 28% as Tb fell from 37 to <31 degrees C and increased during rewarming so that by the time Tb first was >36 degrees C, glucose concentrations had returned to the value preceding torpor. Hamsters did not display torpor when maintained in a long-day length (16 h light/day) and injected with a range of insulin doses (1-50 U/kg body mass), some of which resulted in sustained, pronounced hypoglycemia. We conclude that changes in blood glucose concentrations may be a consequence rather than a cause of the torpid state and question whether induction of torpor by 2-deoxy-D-glucose is due to its general glucoprivic actions.

Melatonin chimeras alter reproductive development and photorefractoriness in Siberian hamsters

Nightly melatonin (MEL) durations > 8 h provoke gonadal regression and decreases in body mass, whereas signals < 7 h stimulate gonadal and somatic growth in male Siberian hamsters. The authors sought to determine the minimum frequency of short MEL signals sufficient to induce the long-day phenotype in several photoperiodic traits. D,L-propranolol (hereafter propranolol) injections shortened MEL signals on the night of treatment without altering MEL on the subsequent night; this permitted interpolation of short MEL signals at variable frequencies against a background of long MEL signals (chimeras). Hamsters kept in short days (10 h light/day, 10L) were injected with propranolol 6 h after dark onset for 28 consecutive weeks beginning at 30 days of age (Week 0) either every other day or once every 3, 6, or 9 days. Control animals were injected with saline or with propranolol during the light phase or were transferred to long days (16L) at Week 0. Hamsters in 16L underwent rapid gonadal development and increases in body mass and displayed summer pelage color, as did hamsters treated with propranolol every other day. Animals treated with propranolol less frequently than every other day uniformly maintained undeveloped gonads and winter-like body weights, but pelage color became proportionately darker with increased frequency of propranolol treatments. The onset of spontaneous testicular development in 10L was unaffected by propranolol injections. After termination of injections at Week 28, testicular regression was not observed in most 10L animals that previously had undergone spontaneous testicular development; however, 40% of hamsters that had been injected with propranolol every 3rd night did manifest the winter phenotype after Week 28. In an alternating sequence, short MEL signals completely override long signals and induce the summer phenotype. Threshold frequencies differ for MEL stimulation of long-day pelage and gonadal phenotypes. The timing and development of refractoriness to MEL does not depend in any simple manner on the number of long MEL signals or on the accumulation of a reaction product produced by long, and depleted by short, MEL signals.

Estradiol phase shifts circannual body mass rhythms of male ground squirrels

Gonadectomized male golden-mantled ground squirrels (Spermophilus lateralis) were implanted with estradiol benzoate (EB)-filled or empty capsules. Body mass was monitored before, during, and for at least 1 yr after hormone treatment. EB treatment during the mass-gain phase of the annual cycle significantly decelerated increases in body mass; the period of the circannual rhythm (CAR) of body mass was 54 days longer in EB- than blank-treated squirrels. Hormone treatment during the mass-loss phase accelerated mass loss; although this effect only approached statistical significance, some phase markers of the CAR were significantly advanced in subsequent cycles. We conclude that, as in females, estradiol affects the waveform of the CAR of males differently at different phases of the circannual cycle. Sexual differentiation does not eliminate responsiveness of CARs of squirrels to estradiol; sex differences, if any, are subtle rather than absolute and, in this respect, differ from circadian rhythms.