Peri-surgical imaging of intersex and gender diverse youths

This publication provides an overview of current imaging indications and practices for patients undergoing gender-affirming surgery, with an emphasis on the importance of tailored, patient-specific care. Gender-affirming surgeries are performed with personalized approaches at various stages of life for those with intersex traits or differences in sex development (I/DSD) and transgender and gender diverse (TGD) individuals. For I/DSD patients, ultrasound, genitography, or MRI occurs during infancy and puberty to evaluate genital and gonadal anatomy. Facial harmonization involves bony and soft tissue modifications, guided by maxillofacial computerized tomography (CT) with three-dimensional reconstruction. Ultrasound is the main modality in assessing hormone-related and post-surgical changes in the chest. Imaging for genital reconstruction uses cross-sectional images and fluoroscopy to assess neoanatomy and complications.

Mendelian Disorders in an Interstitial Cystitis/Bladder Pain Syndrome Cohort

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic pain disorder causing symptoms of urinary frequency, urgency, and bladder discomfort or pain. Although this condition affects a large population, little is known about its etiology. Genetic analyses of whole exome sequencing are performed on 109 individuals with IC/BPS. One family has a previously reported SIX5 variant (ENST00000317578.6:c.472G>A, p.Ala158Thr), consistent with Branchiootorenal syndrome 2 (BOR2). A likely pathogenic heterozygous variant in ATP2A2 (ENST00000539276.2:c.235G>A, p.Glu79Lys) is identified in two unrelated probands, indicating possible Darier-White disease. Two private heterozygous variants are identified in ATP2C1 (ENST00000393221.4:c.2358A>T, p.Glu786Asp (VUS/Likely Pathogenic) and ENST00000393221.4:c.989C>G, p.Thr330Ser (likely pathogenic)), indicative of Hailey-Hailey Disease. Sequence kernel association test analysis finds an increased burden of rare ATP2C1 variants in the IC/BPS cases versus a control cohort (p = 0.03, OR = 6.76), though does not survive Bonferroni correction. The data suggest that some individuals with IC/BPS may have unrecognized Mendelian syndromes. Comprehensive phenotyping and genotyping aid in understanding the range of diagnoses in the population-based IC/BPS cohort. Conversely, ATP2C1, ATP2A2, and SIX5 may be candidate genes for IC/BPS. Further evaluation with larger numbers is needed. Genetically screening individuals with IC/BPS may help diagnose and treat this painful disorder due to its heterogeneous nature.

The radiologist's role in assessing differences of sex development

When infants are identified with a difference of sex development (DSD), a thoughtful approach to imaging is essential to appropriate clinical management. This review provides a comprehensive guide for radiologists who are tasked with performing this critical assignment. We review the embryologic basis of DSDs, with attention to the imaging findings that can indicate specific diagnoses. We also discuss techniques for optimal imaging, including strategies for identifying the gonads by US, tactics for performing genitograms with fluoroscopy and contrast-enhanced US, and the appropriate utilization of MRI. Finally, we review the clinical data and imaging findings that characterize some of the most common DSDs, including congenital adrenal hyperplasia, complete androgen insensitivity syndrome and gonadal dysgenesis.

Clinical outcome of pediatric and young adult subclinical varicoceles: a single-institution experience

Subclinical varicocele represents an abnormality of veins of the pampiniform plexus on scrotal ultrasound (US) without a clinically palpable varicocele. Its significance remains unclear. While guidelines do not recommend surgical intervention, clinical management is variable. As there is limited information on long-term outcome of subclinical varicoceles due to challenges in diagnosis and management, we performed a single-institution, retrospective review of patients from October 1999 to October 2014 with subclinical varicocele and with available US studies reviewed by a single radiologist. Subclinical varicocele was defined as dilation of the pampiniform venous plexus on US involving ≥2 vessels with diameter >2.5 mm, without clinical varicocele on physical examination or prior inguinal surgery. Thirty-six of 98 patients identified were confirmed as having a subclinical varicocele and analyzed. The mean age at initial visit was 15.5 years, with a mean follow-up of 26.5 months. The majority were right-sided (69.4%, n = 25), usually with a contralateral clinical varicocele. Testicular asymmetry (>20% volume difference of the affected side by testicular atrophy index formula) was assessed in 9 patients with unilateral subclinical varicocele without contralateral clinical or subclinical varicocele and observed in 1 patient. Of 17 patients with follow-up, 3 (17.6%) progressed to clinical varicocele without asymmetric testicular volume, as most remained subclinical or resolved without surgery. In our experience, subclinical varicoceles appeared unlikely to progress to clinical varicoceles, to affect testicular volume, or to lead to surgery. Although our study is limited in numbers and follow-up, this information may aid clinical management strategies and guide future prospective studies.

A contemporary single-institution retrospective cohort study comparing perioperative outcomes between robotic and open partial nephrectomy for poorly functioning renal moieties in children with duplex collecting systems

INTRODUCTION

Studies evaluating robotic-assisted laparoscopic partial nephrectomy (RALPN) are limited to case series, amounting to a lack of studies directly comparing perioperative outcomes for RALPN to open partial nephrectomy (OPN).

OBJECTIVE

To compare perioperative outcomes between RALPN and OPN.

METHODS

A single-institution, retrospective cohort study was performed to compare perioperative outcomes (operative time (OT), length of stay (LOS), complications, readmissions, postoperative interventions, loss in size of the residual moiety, and the presence of postoperative 'contained fluid collections') for RALPN and OPN between February 2007 and July 2014. Descriptive statistics were calculated and unadjusted analyses performed, including Chi-squared/Fisher's exact for categorical variables and Wilcoxon rank sum for continuous variables.

RESULTS

During the study period, 43 partial nephrectomies were performed for benign disease: 27 (63%) RALPN and 16 (37%) OPN. The RALPN cohort was significantly older than the OPN cohort (3.5 vs. 0.8 years; P = 0.003). The cohorts were otherwise similar regarding race, American Society of Anesthesiologist score (ASA), affected moiety, laterality, associated anomalies, moiety function, and surgical indication. Robotic-assisted laparoscopic partial nephrectomy was associated with a significantly shorter LOS (1 vs. 3 days; P = 0.002). Operative time and complication rates were comparable. The OPN group had a longer median follow-up (2.7 years vs. 1.1; P = 0.03). No differences were observed between the cohorts for readmissions, postoperative interventions, loss in size of residual moiety, or development of 'contained fluid collections'. These outcomes are reported in the Summary Table. 'Contained fluid collections' occurred more frequently after lower pole resections (73% vs. 30%; P = 0.009).

DISCUSSION

This study is one of the few to directly compare RALPN to OPN, and demonstrated that RALPN has comparable (if not better) outcomes than OPN. In particular, RALPN provides the advantage of a shorter LOS. Avoiding the flank incision used in OPN may also offer reduced pain; however, this was not studied here and the literature provides weak evidence for this effect. This unadjusted analysis may have been confounded by its short median follow-up and significantly younger OPN cohort.

CONCLUSION

In this contemporary comparative analysis, RALPN predicted a similar median OT and safety profile to OPN while offering the advantage of a shorter LOS. Regardless of surgical cohort, there were no adverse effects on the residual renal moieties and postoperative 'contained fluid collections' occurred with notable frequency and were independently associated with lower pole pathology.

Common genitourinary catheters: a systematic approach for the radiologist

Catheters are commonly used to treat and diagnose urinary tract abnormalities in the pediatric population. This pictorial essay reviews commonly placed genitourinary catheters imaged by radiography, fluoroscopy, computed tomography (CT) and ultrasonography (US). The purpose of the catheter, how the catheter is placed, and the imaging findings associated with appropriately positioned catheters as well as misplaced and displaced catheters are described. It is important for radiologists to recognize common genitourinary catheters, and be familiar with their normal and abnormal positions as displacement is often first recognized by diagnostic imaging.

Improving Male Reproductive Health After Childhood, Adolescent, and Young Adult Cancer: Progress and Future Directions for Survivorship Research

Reproductive health is a common concern and often a source of distress for male childhood, adolescent, and young adult cancer survivors. Clinical and epidemiologic research in survivor populations has identified alkylating agent chemotherapy, testicular radiation, and surgery or radiation to the genitourinary organs, lower spine, or the hypothalamic-pituitary region as risk factors for adverse reproductive outcomes, including impaired spermatogenesis, testosterone insufficiency, and sexual dysfunction. Much of the research on male survivors has focused on the outcome of fertility, using spermatogenesis, serum gonadotropins, and paternity as the measures. However, these studies often fail to account for the clinically relevant but difficult-to-quantify aspects of fertility such as sexual function, cancer-related delayed psychosocial development, medical comorbidities, and socioeconomic concerns. Clinical and basic science research has made significant contributions to improving reproductive outcomes for survivors, with recent advancements in the areas of fertility preservation, clinical assessment of reproductive function, and treatment of adverse reproductive outcomes. Furthermore, there is an emerging qualitative literature addressing the psychosexual aspects of male reproductive health, the clinical application of which will improve quality of life for survivors. This review summarizes the current survivorship literature on reproductive health outcomes for male survivors, including the epidemiology of impaired spermatogenesis, testosterone insufficiency, and sexual dysfunction; clinical and laboratory assessment of reproductive function; and established and investigational interventions to preserve reproductive function for patients newly diagnosed and survivors. Although survivorship research has made significant contributions to improving reproductive outcomes, additional scientific progress is needed in the areas of fertility preservation, risk assessment, and psychosexual support with the aim of optimizing reproductive health for current and future survivors.

Minor procedure, major impact: Patient-reported outcomes following urethral meatotomy

INTRODUCTION

Urethral meatotomy as treatment for meatal stenosis is a common pediatric urology procedure; however, little is known about the patient experience following this procedure.

OBJECTIVE

We aim to evaluate clinical factors associated with patient-reported symptom improvement after urethral meatotomy.

STUDY DESIGN

The families of boys undergoing urethral meatotomy between 2/2013 and 8/2016 received a survey by mail 6 weeks after surgery. Families were queried on changes in symptoms using a Likert-type scale (5 = much improved, 4 = somewhat improved, 3 = no change, 2 = somewhat worse, and 1 = much worse). Patient and procedure characteristics of the respondents were obtained via chart review. These included surgical indication(s) (abnormal stream, dysuria, or storage symptoms), postoperative complications, reoperation, and unplanned postoperative communications. Patients who had procedures other than simple urethral meatotomy were excluded. Descriptive statistics were compiled, and generalized estimating equations used to determine the associations of patient and procedure characteristics with symptom improvement.

RESULTS

We sent 629 surveys and received 194 responses (30.4%). Twelve respondents were excluded for complex procedures or miscoding. The majority of respondents were privately insured (74%) and were between 5 and 12 years old (45%) or 1 and 4 years old (42%). The most frequent surgical indication was abnormal stream (72%) followed by pain (21%) and storage symptoms (15.5%). Nine respondents had minor complications (4.9%). Four patients had restenosis requiring repeat urethral meatotomy. After surgery, a majority (79%) were "much improved," 16% were "somewhat improved," 3% had "no change," and 1% were "somewhat worse." No family reported "much worse." Those patients who had "abnormal stream" as a surgical indication were significantly more likely to report "much improved" (OR 1.83, p = 0.014) than those without. Patient-reported improvement was not associated with suture use, patient age, insurance, surgeon, or location of the procedure (Table).

DISCUSSION

Little has been written about patient-reported outcomes following urethral meatotomy. Our study affirms that the majority of boys improve following this procedure. However, improvement is significantly more likely if the child has a preoperative indication of an abnormal stream, such as deflection or spraying. Boys with symptoms of dysuria, frequency, or incontinence may be experiencing sequelae of meatal stenosis that simply take longer to improve. Alternatively, the meatal stenosis may be incidental to the primary symptoms.

CONCLUSIONS

A majority of families report substantial symptomatic improvement after urethral meatotomy. However, boys undergoing urethral meatotomy for reasons other than a urinary stream abnormality are less likely to experience improvement.

Fertility and sexual function: a gap in training in pediatric endocrinology

BACKGROUND

Infertility and sexual dysfunction result from many different pediatric conditions and treatments and can profoundly impact quality of life. The American Academy of Pediatrics (AAP) has recommended consulting "fertility specialists" for counseling, but it remains unclear who these specialists are. Our objective was to assess whether pediatric subspecialists who manage hypogonadism and/or genitourinary conditions feel adequately trained to provide fertility and sexual function counseling.

METHODS

An online survey was distributed to members of Pediatric Endocrine Society (PES), Society for Pediatric Urology (SPU), and North American Society for Pediatric and Adolescent Gynecology (NASPAG). Providers' comfort in counseling various age groups about fertility and sexual function was assessed via a five-point Likert scale. Providers reported whether they felt adequately trained in these areas.

RESULTS

Two hundred and eighty-four surveys were completed by endocrinologists, 124 surveys by urologists, and 41 surveys by gynecologists. Respondents (44% male, 86% Caucasian) represented 39 states and Canada. Seventy-nine percent were at academic centers. Thirty-four percent of providers had been practicing for >20 years. Comfort level was variable and lowest in young males. Ninety-one percent of pediatric endocrinologists reported routinely seeing patients at risk for infertility, but only 36% felt adequately trained in fertility, and 25% felt adequately trained in sexual function.

CONCLUSIONS

Infertility and sexual dysfunction are often overlooked in pediatric care. Our results suggest that pediatric endocrinologists, who frequently manage male and female hypogonadism, should also receive formal training in these areas. Optimizing counseling would help prevent missed opportunities for fertility preservation and alleviate distress among patients and families.

Robotic versus open pediatric ureteral reimplantation: Costs and complications from a nationwide sample

INTRODUCTION

We sought to compare complications and direct costs for open ureteral reimplantation (OUR) versus robot-assisted laparoscopic ureteral reimplantation (RALUR) in a sample of hospitals performing both procedures. Anecdotal reports suggest that use of RALUR is increasing, but little is known of the outcomes and costs nationwide.

OBJECTIVE

The aim was to determine the costs and 90-day complications (of any Clavien grade) in a nationwide cohort of pediatric patients undergoing OUR or RALUR.

METHODS

Using the Premier Hospital Database we identified pediatric patients (age < 21 years) who underwent ureteral reimplantation from 2003 to 2013. We compared 90-day complication rates and cost data for RALUR versus OUR using descriptive statistics and hierarchical models.

RESULTS

We identified 17 hospitals in which both RALUR and OURs were performed, resulting in a cohort of 1494 OUR and 108 RALUR cases. The median operative time was 232 min for RALUR vs. 180 min for OUR (p = 0.0041). Incidence of any 90-day complications was higher in the RALUR group: 13.0% of RALUR vs. 4.5% of OUR (OR = 3.17, 95% CI: 1.46-6.91, p = 0.0037). The difference remained significant in a multivariate model accounting for clustering among hospitals and surgeons (OR, 3.14; 95% CI, 1.46-6.75; p = 0.0033) (Figure). The median hospital cost for OUR was $7273 versus $9128 for RALUR (p = 0.0499), and the difference persisted in multivariate analysis (p = 0.0043). Fifty-one percent (55/108) of the RALUR cases occurred in 2012-2013.

DISCUSSION

We present the first nationwide sample comparing RALUR and OUR in the pediatric population. There is currently wide variation in the probability of complication reported in the literature. Some variability may be due to differential uptake and experience among centers as they integrate a new procedure into their practice, while some may be due to reporting bias. A strength of the current study is that cost and 90-day postoperative complication data are collected at participating hospitals irrespective of outcomes, providing some immunity from the reporting bias to which individual center surgical series' may be susceptible.

CONCLUSIONS

Compared with OUR, RALUR was associated with a significantly higher rate of complications as well as higher direct costs even when adjusted for demographic and regional factors. These findings suggest that RALUR should be implemented with caution, particularly at sites with limited robotic experience, and that outcomes for these procedures should be carefully and systematically tracked.

Robotic-assisted laparoscopic bladder augmentation in the pediatric patient

INTRODUCTION

Bladder augmentation is a common surgical intervention for neuropathic bladder dysfunction, and has conventionally been an open procedure. We present a robotic ileocystoplasty to demonstrate the feasibility of an entirely intracorporeal approach in a pediatric patient.

METHODS

The patient was a 6 year old (18.5 kg) boy with a neurogenic bladder secondary to lumbar myelomeningocele. Urodynamics revealed a small capacity and poorly compliant bladder and he was incontinent between frequent catheterizations. A robotic augmentation cystoplasty was performed.

RESULTS

At one-month postoperatively, a cystogram revealed no urine leak, and the suprapubic tube was removed. The patient resumed CIC every 3 h during the day and once overnight until postoperative urodynamic studies confirmed safe dynamics, after which the CIC interval was lengthened.

CONCLUSION

Robotic bladder augmentation is safe and feasible in a select pediatric population. The entire procedure including preparation of the bowel segment can be completed intracorporeally, even in smaller children.

Pediatric Robot-Assisted Laparoscopic Pyeloplasty

The laparoscopic approach to the pyeloplasty procedure has proven to be safe and effective in the pediatric population. Multiple studies have revealed outcomes comparable to the open approach. However, a major drawback to laparoscopy is the technical challenge of precise suturing in the small working space in children. The advantages of robotic surgery when compared to conventional laparoscopy have been well established and include motion scaling, enhanced magnification, 3-dimensional stereoscopic vision, and improved instrument dexterity. As a result, surgeons with limited laparoscopic experience are able to more readily acquire robotic surgical skills. Limitations of the robotic platform include its high costs for acquisition and maintenance, as well as the need for additional robotic surgical training. In this article, we review the current status of the robot-assisted laparoscopic pyeloplasty, including a brief history, comparative outcomes, cost considerations, and training.

Sperm Retrieval in Adolescents and Young Adults with Klinefelter Syndrome: A Prospective, Pilot Study

OBJECTIVE

To assess sperm retrieval rates in adolescents and young adults with Klinefelter syndrome, with the ultimate goal of improving fertility in this population. Secondary aims were to evaluate other clinical characteristics of the cohort and identify predictors of sperm retrieval.

STUDY DESIGN

Patients 12-25 years of age with Klinefelter syndrome (47,XXY) were recruited at the Boston Children's Hospital. Physical examination, biochemical evaluation, scrotal ultrasonography, and semen analysis were performed. Neurocognitive data were collected. Microdissection sperm extraction (unilateral micro-testicular sperm extraction) was offered to individuals with no sperm in their ejaculates. Given the small sample size, analysis was primarily descriptive.

RESULTS

Fifteen patients were enrolled. None had sperm in their ejaculates. Ten patients underwent unilateral micro-testicular sperm extraction. Sperm retrieval rate was 50%. From a neurocognitive standpoint, subjects reported problems with peers, conduct, and overall difficulties. Incidentally, one-third of the patients were found to have testicular microlithiasis and 17% of subjects with renal ultrasound imaging had bilateral renal medullary nephrocalcinosis.

CONCLUSIONS

This pilot study suggests that sperm retrieval rates in adolescents and young adults with Klinefelter syndrome are comparable with those reported in older men. However, larger studies are needed to confirm our findings. The clinical significance of the scrotal and renal ultrasound findings merits further investigation.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01817296.

Management of testosterone therapy in adolescents and young men with hypogonadism: are we following adult clinical practice guidelines?

OBJECTIVE

Male hypogonadism is a common disorder that is associated with low bone density, poor muscle mass, anemia, and sexual dysfunction. The Endocrine Society recently published a Clinical Practice Guideline for testosterone therapy in androgen-deficient men. Because treatment is frequently initiated in adolescence, the goal of this quality improvement initiative was to assess whether pediatric endocrinologists at a large tertiary care center follow these guidelines and to identify opportunities for improvement.

DESIGN

We performed a retrospective chart review at Boston Children's Hospital. Inclusion criteria were as follows: current age ≥16 years, diagnosis of hypogonadism, and testosterone replacement therapy. Data were collected about current age, age at treatment initiation, diagnoses, pre- and on-treatment testosterone levels, route of testosterone administration and dose, bone density, hematocrit levels, and adherence with therapy.

RESULTS

Fifty-nine patients were included. Fourteen (24%) were prescribed lower testosterone doses than those recommended in the Clinical Practice Guideline. Seven (12%) had no pre-treatment testosterone levels, and 10 (17%) had no on-treatment levels. In 49 patients with on-treatment testosterone levels, 36 had at least one value that was lower than the adult reference range. Ten (28%) of the 36 men with low testosterone levels had no dose adjustments. Thirty-seven (63%) of the 59 patients had no dual-energy X-ray absorptiometry scans, and 18 (31%) did not have hematocrit levels.

CONCLUSIONS

Pediatric endocrinologists in this review did not consistently follow the Clinical Practice Guideline for testosterone therapy in hypogonadal adult males. Strategies that improve adherence to guidelines could help maximize the benefits of therapy and minimize treatment-associated risks.

Prepubertal presentation of varicocele does not affect outcomes

INTRODUCTION

Varicoceles in prepubertal boys are uncommon and little is known of the natural history. Historically, a large percentage of these boys have undergone surgical repair with the belief that such early presentation carried a worse prognosis, making assessment of longitudinal outcomes difficult.

OBJECTIVE

While there may be concern that varicocele could represent a progressive disease and therefore prepubertal presentation would portend a worse prognosis, we hypothesized that there would be no difference between the prepubertal boys and other adolescents with varicocele.

STUDY DESIGN

We retrospectively reviewed a database of boys at a single institution with a documented left-sided varicocele between 1995 and 2011. Inclusion criteria were one or more of the following: 1. Clinician-documented Tanner 1 status, 2. Right testis orchidometric or ultrasound calculated volume of ≤3 cc's. Patients were drawn from a prospectively maintained database of all boys presenting to the outpatient urology clinic receiving a diagnosis of varicocele. A cohort of adolescent boys was assembled by matching as closely as possible with respect to testis volume disparity and grade of varicocele. All matches were within 2% of volume difference. Volume was calculated using the length*width*height*0.71 formula. Testis size disparity was set to a threshold of ≥20% using the Lambert formula: (VolumeRight - VolumeLeft)/VolumeRight*100%. Our primary outcome was defined as hypotrophy or the need for surgery for hypotrophy at the termination of the study. We planned a single subgroup analysis of boys based on presentation with or without hypotrophy. The decision for surgery or observation was made by the individual clinician at the time of patient assessment.

RESULTS

On presentation, the prepubertal cohort was younger (10.8 vs 14.1 years), and with smaller left (2.4 vs 11.6 cc) and right (2.4 vs 11.6 cc) testis volume. There were no significant differences with respect to varicocele grade and volume differentials at presentation. At the end of the study, 76% of the prepubertal cohort had neither hypotrophy nor the requirement for operation, compared with 83% of the matched cohort (P = 0.71, Fisher's exact test). Similarly, there were no significant differences in outcome when comparing prepubertal boys with initial symmetry or hypotrophy to their matched cohort of older adolescents.

DISCUSSION

The prepubertal varicocele is a rare clinical problem for which little data exists to guide the clinician. In a review of Pubmed indexed English language manuscripts, we were only able to find five papers with information on Tanner stage; only 31 prepubertal boys have longitudinal data reported. This study approximately doubles the number of boys for whom such data is available in the literature. Our chief limitation was sample size. A power analysis indicated that a final-analysis cohort of 90 prepubertal boys would be required to detect a 20% difference in outcome between that group and a matched cohort of pubertal or post-pubertal boys. We propose that given the lack of evidence for worse outcomes in prepubertal boys with varicocele that prepubertal status, in and of itself, not be considered an additional indication for correction of varicocele.

CONCLUSION

In our retrospective cohort of prepubertal boys with left testis varicocele and their matched cohort, we did not detect a difference in the rate of good outcomes, defined as the absence of hypotrophy and lack of need for surgical intervention. While we may have suspected, as have others, that prepubertal presentation would have conveyed a more pressing need to intervene, it is likely that these boys represent the very same patients that we see more commonly later in their adolescence, and should thus be managed in a similarly conservative fashion.

Klinefelter syndrome: are we missing opportunities for early detection?

Klinefelter syndrome is a common condition that remains underdiagnosed, particularly prior to adulthood. Early detection could prevent morbidity and mortality, but the classic phenotype of small testes and tall stature may not be apparent until adolescence, and there is minimal guidance regarding whom to screen. We performed a retrospective study at Boston Children's Hospital in patients with the ICD-9 code for "Klinefelter syndrome" diagnosed prior to age 20 years, and determined age and reason for diagnosis, karyotype, heights, and comorbid conditions. Eighty percent had a 47,XXY karyotype, of whom half were diagnosed at age 11 to 19 years. The most common comorbidities were neurocognitive, including learning disabilities (67%), psychosocial problems (33%), and attention deficit disorder (27%). Subjects were only slightly taller than average in childhood (height standard deviation score = 0.64). These data show that Klinefelter syndrome is associated with long-standing comorbidities that frequently remain under-recognized; a karyotype should be considered in boys with neurocognitive problems.

Predicting anatomical urological abnormalities in children who present with their first urinary tract infection

OBJECTIVES

Classically, presence of fever≥38.0°C is used to distinguish pyelonephritis from cystitis. We analyzed whether this is an appropriate marker to initiate further workup and whether temperature is correlated with urological abnormalities and further surgical or pharmacological intervention.

METHODS

Children who presented for their first workup of urinary tract infection between October 1, 2008, and September 30, 2009 were retrospectively selected from our institution. Demographics and clinical details were correlated with the diagnosis of urological abnormalities and requirement for intervention.

RESULTS

Age was the most important variable to predict urological abnormalities. The temperature value of 38.3°C maximized the balance between sensitivity (90%) and specificity (46%) for predicting the need to intervene and the presence of anatomical urological abnormalities.

CONCLUSION

Young age (≤2 years) and temperature are the best factors to predict further intervention and urological abnormalities, with a temperature value of 38.3°C being a better predictive value than the currently used 38.0°C.

Semen analysis in adolescent cancer patients prior to bone marrow transplantation: when is it too late for fertility preservation?

BACKGROUND

Sperm banking is an effective method of fertility preservation in adolescent boys with cancer but is strikingly underutilized, partly due to inconsistencies in fertility counseling and unclear guidelines regarding who should bank sperm. Patients undergoing bone marrow transplantation (BMT) are of particular interest given the high risk of infertility in this population.

PROCEDURE

We reviewed the charts of male cancer patients who underwent BMT at age ≥13 years at the Dana-Farber Cancer Institute (DFCI) from 2003 to 2010 to determine the number of fertility preservation attempts prior to initial treatment and/or BMT, and the outcomes of those sperm banking attempts.

RESULTS

Sixty-eight male cancer patients who had a BMT at age ≥13 years at the DFCI from 2003 to 2010 were included in the analysis. Six patients had attempted sperm banking prior to initial therapy. Thirty-three patients attempted to bank prior to BMT; of those, 39% were azoospermic and 15% were oligospermic. Nineteen patients did not attempt to bank, and in 13 patients the decision to bank was unclear.

CONCLUSIONS

A more consistent approach to fertility counseling is essential for adolescent cancer patients. Though first line therapy may be low-risk in terms of long-term impact on fertility, our results demonstrate that transient gonadal dysfunction is common and ongoing chemotherapy may affect spermatogenesis. Should a patient undergo BMT during this period, sperm banking is unlikely to be successful; initial fertility risk assessment should account for this possibility.

Small-molecule inhibition of BRDT for male contraception

A pharmacologic approach to male contraception remains a longstanding challenge in medicine. Toward this objective, we explored the spermatogenic effects of a selective small-molecule inhibitor (JQ1) of the bromodomain and extraterminal (BET) subfamily of epigenetic reader proteins. Here, we report potent inhibition of the testis-specific member BRDT, which is essential for chromatin remodeling during spermatogenesis. Biochemical and crystallographic studies confirm that occupancy of the BRDT acetyl-lysine binding pocket by JQ1 prevents recognition of acetylated histone H4. Treatment of mice with JQ1 reduced seminiferous tubule area, testis size, and spermatozoa number and motility without affecting hormone levels. Although JQ1-treated males mate normally, inhibitory effects of JQ1 evident at the spermatocyte and round spermatid stages cause a complete and reversible contraceptive effect. These data establish a new contraceptive that can cross the blood:testis boundary and inhibit bromodomain activity during spermatogenesis, providing a lead compound targeting the male germ cell for contraception.

PaperClip

Urological complications and vesicoureteral reflux following pediatric kidney transplantation

PURPOSE

Ureteral complications of renal transplantation can dramatically impact renal outcomes. We studied whether complications are associated with preexisting genitourinary pathology or transplant using a deceased donor allograft.

MATERIALS AND METHODS

We retrospectively reviewed all patients undergoing renal transplantation at our institution between 2000 and 2010. We abstracted patient demographic details, donor type (living vs deceased), end-stage renal disease etiology, reimplant technique, stent use, preoperative and postoperative imaging, history of lower genitourinary pathology and postoperative complication management.

RESULTS

A total of 211 kidneys were transplanted into 206 patients (mean age 13.7 years, mean followup 4.6 years). Most patients (89%) underwent extravesical ureteroneocystostomy without stenting (97%), with roughly half (47%) of transplants being from living donors. Preexisting urological pathology was present in 34% of cases. Postoperative obstruction or extravasation occurred in 16 cases (7.6%), of which 15 were acute. Complications were not associated with donor type, preexisting urological pathology other than posterior urethral valves, surgical technique, etiology of end-stage renal disease or patient age. However, posterior urethral valves or other preexisting genitourinary pathology was not associated with an increased likelihood of genitourinary complications. Posterior urethral valves were associated with development of postoperative vesicoureteral reflux (OR 6.7, p = 0.004) but were not associated with stent placement, surgical technique, donor type or etiology of end-stage renal disease.

CONCLUSIONS

Patients with posterior urethral valves undergoing renal transplantation are at increased risk for postoperative vesicoureteral reflux but not for other acute surgical complications. There is no association between donor type, etiology of end-stage renal disease, surgical technique or patient age and increased complications.

Adult care of children from pediatric urology

PURPOSE

In this article we highlight the difference, from established adult urology, in required approach to the care of adolescents and young adults presenting with the long-term consequences of the major congenital anomalies of the genitourinary tract. We review some abnormalities of the kidneys, progressive renal failure and disorders of bladder function from which general conclusions can be drawn.

MATERIALS AND METHODS

The published literature was reviewed and augmented with material from our institutional databases. For renal function the CAKUT (congenital abnormalities of the kidney and urinary tract) database at University College London Hospitals was used, which includes 101 young adult patients with CAKUT in whom the urinary tract has not been diverted or augmented. For bladder function some data are from patient records at Boston Children's Hospital.

RESULTS

Adolescents who grow up with the burden of a major congenital anomaly have an overwhelming desire to be normal. Many achieve high levels of education and occupy a wide range of employment scenarios. Babies born with damaged kidneys will usually experience improvement in renal function in the first 3 years of life. Approximately 50% of these cases will remain stable until puberty, after which half of them will experience deterioration. Any urologist who treats such patients needs to test for proteinuria as this is a significant indicator of such deterioration. In its absence, the urologist must have a reasonable strategy for seeking a urological cause. The most effective management for nephrological renal deterioration is with angiotensin converting enzyme inhibitors, which slow but do not prevent end stage renal failure. Renal deterioration is generally slower in these patients than in those with other forms of progressive renal disease. The bladder is damaged by obstruction or by functional abnormalities such as myelomeningocele. Every effort should be made to stabilize or reconstruct the bladder in childhood. A dysfunctional bladder is associated with or causes renal damage in utero, but continued dysfunction will cause further renal damage. Bladder function often changes in puberty, especially in boys with posterior urethral valves who may experience high pressure chronic retention. Dysfunction is managed with antimuscarinic drugs, clean intermittent self-catheterization and intestinal augmentation. Adult urologists must be able to manage the long-term problems associated with these treatments.

CONCLUSIONS

Pediatric conditions requiring management in adolescence are rare but have major, lifelong implications. Their management requires a broad knowledge of pediatric and adult urology, and could well be a specialty in its own right. Therefore, adult urologists must remain aware of the conditions, the problems that they may encounter and the special management required for these patients to live normal lives.

All-trans retinoic acid directs urothelial specification of murine embryonic stem cells via GATA4/6 signaling mechanisms

The urinary bladder and associated tract are lined by the urothelium, a transitional epithelium that acts as a specialized permeability barrier that protects the underlying tissue from urine via expression of a highly specific group of proteins known as the uroplakins (UP). To date, our understanding of the developmental processes responsible for urothelial differentiation has been hampered due to the lack of suitable models. In this study, we describe a novel in vitro cell culture system for derivation of urothelial cells from murine embryonic stem cells (ESCs) following cultivation on collagen matrices in the presence all trans retinoic acid (RA). Upon stimulation with micromolar concentrations of RA, ESCs significantly downregulated the pluripotency factor OCT-4 but markedly upregulated UP1A, UP1B, UP2, UP3A, and UP3B mRNA levels in comparison to naïve ESCs and spontaneously differentiating controls. Pan-UP protein expression was associated with both p63- and cytokeratin 20-positive cells in discrete aggregating populations of ESCs following 9 and 14 days of RA stimulation. Analysis of endodermal transcription factors such as GATA4 and GATA6 revealed significant upregulation and nuclear enrichment in RA-treated UP2-GFP+ populations. GATA4-/- and GATA6-/- transgenic ESC lines revealed substantial attenuation of RA-mediated UP expression in comparison to wild type controls. In addition, EMSA analysis revealed that RA treatment induced formation of transcriptional complexes containing GATA4/6 on both UP1B and UP2 promoter fragments containing putative GATA factor binding sites. Collectively, these data suggest that RA mediates ESC specification toward a urothelial lineage via GATA4/6-dependent processes.

Variation among internet based calculators in predicting spontaneous resolution of vesicoureteral reflux

PURPOSE

An increasing number of parents and practitioners use the Internet for health related purposes, and an increasing number of models are available on the Internet for predicting spontaneous resolution rates for children with vesicoureteral reflux. We sought to determine whether currently available Internet based calculators for vesicoureteral reflux resolution produce systematically different results.

MATERIALS AND METHODS

Following a systematic Internet search we identified 3 Internet based calculators of spontaneous resolution rates for children with vesicoureteral reflux, of which 2 were academic affiliated and 1 was industry affiliated. We generated a random cohort of 100 hypothetical patients with a wide range of clinical characteristics and entered the data on each patient into each calculator. We then compared the results from the calculators in terms of mean predicted resolution probability and number of cases deemed likely to resolve at various cutoff probabilities.

RESULTS

Mean predicted resolution probabilities were 41% and 36% (range 31% to 41%) for the 2 academic affiliated calculators and 33% for the industry affiliated calculator (p = 0.02). For some patients the calculators produced markedly different probabilities of spontaneous resolution, in some instances ranging from 24% to 89% for the same patient. At thresholds greater than 5%, 10% and 25% probability of spontaneous resolution the calculators differed significantly regarding whether cases would resolve (all p <0.0001).

CONCLUSIONS

Predicted probabilities of spontaneous resolution of vesicoureteral reflux differ significantly among Internet based calculators. For certain patients, particularly those with a lower probability of spontaneous resolution, these differences can significantly influence clinical decision making.

Renal ultrasound studies after endoscopic injection of dextranomer/hyaluronic acid copolymer for vesicoureteral reflux

OBJECTIVES

To examine the outcomes of renal ultrasound studies after subureteral injection of dextranomer/hyaluronic acid copolymer and provide recommendations for postoperative management of vesicoureteral reflux (VUR).

METHODS

Pediatric patients aged 15 years or younger with uncomplicated primary VUR were recruited for endoscopic treatment with dextranomer/hyaluronic acid gel. After undergoing the procedure, patients were instructed to continue prophylactic antibiotic treatment until a follow-up voiding cystourethrogram was obtained 2 weeks or more after treatment. VUR resolution was defined as grade 0. Repeat endoscopic injection was offered to patients with persistent VUR. Postoperative renal ultrasound scans were obtained on the same day as the voiding cystourethrogram.

RESULTS

Of 120 patients treated, 6 were lost to follow-up and 14 had not yet undergone the posttreatment evaluation. The 100 remaining patients (efficacy population) had a mean age of 4.2 years (range 0.5 to 15), and the median reflux grade was 2 (range 1 to 5). The overall VUR resolution rate for the patients was 87% after endoscopic injection. Of 100 patients, 88 achieved complete resolution after a single injection and 19 required a repeat injection. Of the 100 patients who underwent postoperative ultrasound examination, none demonstrated renal ultrasound changes consistent with significant ureteral obstruction or renal parenchymal changes.

CONCLUSIONS

Renal ultrasound studies after endoscopic treatment with dextranomer/hyaluronic acid gel are unnecessary after determination of reflux resolution by voiding cystourethrography.

Treatment of vesicoureteral reflux using endoscopic injection of nonanimal stabilized hyaluronic acid/dextranomer gel: initial experience in pediatric patients by a single surgeon

OBJECTIVE

Endoscopic injection of nonanimal stabilized hyaluronic acid/dextranomer gel is an increasingly recognized treatment option for vesicoureteral reflux. The procedure is minor compared with open surgery and, when successful, avoids the need for long-term antibiotic prophylaxis. We present data from our first 18 months using nonanimal stabilized hyaluronic acid/dextranomer gel to treat children with vesicoureteral reflux.

PATIENTS AND METHODS

Pediatric patients aged < or = 15 years with uncomplicated primary vesicoureteral reflux were recruited for endoscopic treatment with nonanimal stabilized hyaluronic acid/dextranomer gel. A follow-up voiding cystourethrogram was scheduled at > or = 2 weeks after treatment, and vesicoureteral reflux resolution was defined as grade 0. Repeat nonanimal stabilized hyaluronic acid/dextranomer gel treatment was offered to patients with persistent vesicoureteral reflux.

RESULTS

Of 120 patients treated, 6 were lost to follow-up, and 7 were yet to undergo posttreatment voiding cystourethrogram. The 107 remaining patients (efficacy population) had a mean age of 4.1 years (range: 0.5-15.0), and the median reflux grade was 2 (range: 1-5). The mean time to follow-up voiding cystourethrogram was 9.7 weeks (range: 2-26). Vesicoureteral reflux was resolved in 82.2% of patients and 86.9% of ureters after initial endoscopic treatment with nonanimal stabilized hyaluronic acid/dextranomer gel. The overall reflux resolution rate for patients increased to 90.7% after a second treatment in 14 patients. Two patients reported postoperative flank pain, although this was mild and transient in nature. No other adverse events were reported. No patients underwent open surgery for vesicoureteral reflux.

CONCLUSIONS

Endoscopic treatment with nonanimal stabilized hyaluronic acid/dextranomer gel is effective in a high proportion of children with vesicoureteral reflux and, in our opinion, may be considered as a first-line treatment option.

A murine model of autosomal dominant neurohypophyseal diabetes insipidus reveals progressive loss of vasopressin-producing neurons

Familial neurohypophyseal diabetes insipidus (FNDI) is an autosomal dominant disorder caused by mutations in the arginine vasopressin (AVP) precursor. The pathogenesis of FNDI is proposed to involve mutant protein-induced loss of AVP-producing neurons. We established murine knock-in models of two different naturally occurring human mutations that cause FNDI. A mutation in the AVP signal sequence [A(-1)T] is associated with a relatively mild phenotype or delayed presentation in humans. This mutation caused no apparent phenotype in mice. In contrast, heterozygous mice expressing a mutation that truncates the AVP precursor (C67X) exhibited polyuria and polydipsia by 2 months of age and these features of DI progressively worsened with age. Studies of the paraventricular and supraoptic nuclei revealed induction of the chaperone protein BiP and progressive loss of AVP-producing neurons relative to oxytocin-producing neurons. In addition, Avp gene products were not detected in the neuronal projections, suggesting retention of WT and mutant AVP precursors within the cell bodies. In summary, this murine model of FNDI recapitulates many features of the human disorder and demonstrates that expression of the mutant AVP precursor leads to progressive neuronal cell loss.

Aromatase (Cyp19) expression is up-regulated by targeted disruption of Dax1

DAX-1 [dosage-sensitive sex reversal, adrenal hypoplasia congenita (AHC) critical region on the X chromosome, gene 1] is an orphan nuclear receptor that represses transcription by steroidogenic factor-1 (SF-1), a factor that regulates expression of multiple steroidogenic enzymes and other genes involved in reproduction. Mutations in the human DAX1 gene (also known as AHC) cause the X-linked syndrome AHC, a disorder that is associated with hypogonadotropic hypogonadism also. Characterization of Dax1-deficient male mice revealed primary testicular defects that included Leydig cell hyperplasia (LCH) and progressive degeneration of the germinal epithelium, leading to infertility. In this study, we investigated the effect of Dax1 disruption on the expression profile of various steroidogenic enzyme genes in Leydig cells isolated from Dax1-deficient male mice. Expression of the aromatase (Cyp19) gene, which encodes the enzyme that converts testosterone to estradiol, was increased significantly in the Leydig cells isolated from mutant mice, whereas the expression of other proteins (e.g., StAR and Cyp11a) was not altered. In in vitro transfection studies, DAX-1 repressed the SF-1-mediated transactivation of the Cyp19 promoter but did not inhibit the StAR or Cyp11a promoters. Elevated Cyp19 expression was accompanied by increased intratesticular levels of estradiol. Administration of tamoxifen, a selective estrogen-receptor modulator, restored fertility to the Dax1-deficient male mice and partially corrected LCH, suggesting that estrogen excess contributes to LCH and infertility. Based on these in vivo and in vitro analyses, aromatase seems to be a physiologic target of Dax-1 in Leydig cells, and increased Cyp19 expression may account, in part, for the infertility and LCH in Dax1-deficient mice.

Sertoli cell-specific rescue of fertility, but not testicular pathology, in Dax1 (Ahch)-deficient male mice

DAX1 is an orphan member of the nuclear hormone receptor superfamily of transcription factors. Our recent characterization of Dax1 (Ahch)-deficient male mice revealed a primary testicular defect resulting in hypogonadism and sterility. The progressive degeneration of the germinal epithelium, independent of abnormal gonadotropin and testosterone production, suggested an intrinsic loss of Dax1 function in the Sertoli cells. To test this hypothesis, we assessed the effect of Sertoli cell-specific expression of a human DAX1 (AHC) transgene driven using the promoter of the Müllerian inhibiting substance (MIS) gene. The MIS-DAX1 transgene partially rescued the mutant phenotype of the Dax1-deficient male mice. Although testicular morphology remained abnormal, fertility was restored to levels matching that of wild-type littermates. Examination of several markers of sperm fertilizing capability revealed significant improvements in MIS-DAX1-rescued mice. Epididymal sperm count and sperm motility were greater in 12-week-old rescued mice than in age-matched Dax1-deficient mice. The ability of sperm to undergo an immediate acrosome reaction was impaired in Dax1-deficient animals, and sperm from Dax1-deficient mice fertilized only 8.2 +/- 6.8% of eggs in vitro, significantly less than rescue (67.8 +/- 19.1%) and wild-type (88.9 +/- 3.9%) sperm. These results indicate that Dax1 expression in Sertoli cells is adequate to overcome crucial thresholds related to sperm production and function. However, the failure to completely rescue the testicular pathology of Dax1-deficient mice suggests that Dax1 expression in other somatic cells is essential for normal testicular development.

Mutant vasopressin precursors that cause autosomal dominant neurohypophyseal diabetes insipidus retain dimerization and impair the secretion of wild-type proteins

Autosomal dominant familial neurohypophyseal diabetes insipidus is caused by mutations in the arginine vasopressin (AVP) gene. We demonstrated recently that mutant AVP precursors accumulate within the endoplasmic reticulum of neuronal cells, leading to cellular toxicity. In this study, the possibility that mutant AVP precursors interact with wild-type (WT) proteins to alter their processing and function was explored. WT and mutant precursors were epitope-tagged to allow them to be distinguished in transfected cells. An in vivo cross-linking reaction revealed homo- and heterodimer formation between WT and mutant precursors. Mutant precursors were also shown to impair intracellular trafficking of WT precursors from the endoplasmic reticulum to the Golgi apparatus. In addition to the cytotoxicity caused by mutant AVP precursors, the interaction between the WT and mutant precursors suggests that a dominant-negative mechanism may also contribute to the pathogenesis of familial neurohypophyseal diabetes insipidus.

Role of Ahch in gonadal development and gametogenesis

Ahch (also known as Dax1) encodes a transcription factor that has been implicated in sex determination and gonadal differentiation. Mutations in human AHC cause X-linked, adrenal hypoplasia congenita (AHC) and hypogonadotropic hypogonadism (HH). Duplication of the Xp21 dosage-sensitive sex reversal (DSS) region, which contains the Ahch locus, and transgenic overexpression of Ahch cause male-to-female sex reversal. Using Cre-mediated disruption of Ahch, we have generated a mouse model of AHC-HH that allows the function of Ahch to be examined in both males and females. Although Ahch has been postulated to function as an ovarian determination gene, the loss of Ahch function in females does not affect ovarian development or fertility. Ahch is instead essential for the maintenance of spermatogenesis. Lack of Ahch causes progressive degeneration of the testicular germinal epithelium independent of abnormalities in gonadotropin and testosterone production and results in male sterility. Ahch is thus not an ovarian determining gene, but rather has a critical role in spermatogenesis.

The murine Dax-1 promoter is stimulated by SF-1 (steroidogenic factor-1) and inhibited by COUP-TF (chicken ovalbumin upstream promoter-transcription factor) via a composite nuclear receptor-regulatory element

The Dax-1 gene encodes a protein that is structurally related to members of the orphan nuclear receptor superfamily. Dax-1 is coexpressed with another orphan nuclear receptor, steroidogenic factor-1 (SF-1), in the adrenal, gonads, hypothalamus, and pituitary gland. Mutations in Dax-1 cause adrenal hypoplasia congenita, a disorder that is characterized by adrenal insufficiency and hypogonadotropic hypogonadism. These developmental and endocrine abnormalities are similar to those caused by disruption of the murine Ftz-F1 gene (which encodes SF-1), suggesting that these nuclear receptors act along the same developmental cascade. Cloning of the murine Dax-1 gene revealed a candidate SF-1-binding site in the Dax-1 promoter. In transient expression assays in SF-1-deficient JEG-3 cells, SF-1 stimulated expression of the Dax-1 promoter. However, deletion or mutation of the consensus SF-1-binding site did not eliminate SF-1 stimulation. Further analyses revealed the presence of a cryptic SF-1 site that creates an imperfect direct repeat of the SF-1 element. When linked to the minimal thymidine kinase promoter, each of the isolated SF-1 sites was sufficient to mediate transcriptional regulation by SF-1. Mutation of both SF-1 sites eliminated SF-1 binding and stimulation of the Dax-1 promoter. Unexpectedly, mutation of either half of the composite SF-1 sites increased basal activity in JEG-3 cells, suggesting interaction of a repressor protein. Gel shift analyses of the composite response element revealed an additional complex that was not supershifted by SF-1 antibodies. This complex was eliminated by mutation of either half-site, and it was supershifted by antibodies against chicken ovalbumin upstream promoter-transcription factor (COUP-TF). We propose that Dax-1 is stimulated by SF-1, and that SF-1 and COUP-TF provide antagonistic pathways that converge upon a common regulatory site.

The Role of DAX-1 in Reproduction

Mutations in a gene referred to as Dax-1 cause an X-linked form of adrenal hypoplasia congenita (AHC). The disorder is limited to males and is characterized by neonatal adrenal insufficiency and failure to undergo puberty because of hypogonadotropic hypogonadism. Consistent with these clinical manifestations, the Dax-1 gene is expressed in the adrenal gland, gonads, hypothalamus and pituitary gland. The DAX-1 protein is structurally related to orphan nuclear receptors, although it lacks the characteristic zinc finger DNA-binding domain that is highly conserved in other members of this family. Dax-1 has been shown to repress the transcription of genes that are regulated by another nuclear receptor, steroidogenic factor-1 (SF-1). AHC mutations in Dax-1 eliminate its repressive activity. Genetic testing for Dax-1 mutations will enhance our ability to diagnose and treat AHC. Studies of the biological role of Dax-1 will provide new insights into the development and function of the adrenal gland and the reproductive axis.

Steroidogenic factor-1 contains a carboxy-terminal transcriptional activation domain that interacts with steroid receptor coactivator-1

The orphan nuclear receptor, steroidogenic factor-1 (SF-1), plays an important role in the development of the adrenal gland and in sexual differentiation. SF-1 regulates the transcription of variety of genes, including several steroidogenic enzymes, Müllerian inhibiting substance, and gonadotropin genes. In this report, we sought to identify domains in SF-1 that are required for transactivation and to determine whether SF-1 interacts with a subset of known coactivators. Natural variants of the FTZ-F1 locus include embryonal long terminal repeat-binding protein (ELP)-1, ELP-2, and SF-1, which share the DNA-binding domain. Analyses of the transcriptional activity of these variants revealed that the activity of ELP-2 and SF-1 was much greater than ELP-1, which contains a distinct carboxy terminus. Further studies were performed using GAL4-SF-1 fusion proteins that were constructed by replacement of the zinc finger region and FTZ-F1 box of SF-1 with the DNA-binding domain of GAL4. Elimination of the putative AF-2 domain at the carboxy terminus of GAL4-SF-1 proteins resulted in a complete loss of transactivation. Several lines of evidence demonstrated that SF-1 interacts with steroid receptor coactivator-1 (SRC-1). Full-length SRC-1 enhanced GAL4-SF-1-mediated transactivation, whereas a dominant negative form of SRC-1, consisting of its interaction domain alone, inhibited the activity of GAL4-SF-1. In mammalian two-hybrid assays, fusion of the VP16 activation domain to the interaction domain of SRC-1 confirmed the interaction between SRC-1 and GAL4-SF-1 and demonstrated that the AF-2 domain is required for interaction with SRC-1. Furthermore, SRC-1, together with the cAMP responsive element binding protein (CBP) or a closely related factor, p300, synergistically enhanced transcriptional activity of GAL4-SF-1. We conclude that the carboxy-terminal AF-2 region of SF-1 functions as an activation domain and that SRC-1 and CBP/p300 are components of the coactivator complex with SF-1.

The first human alpha-spectrin structural domain begins with serine

The 106-amino acid sequence motifs of spectrin have been suggested to fold into stable structural domains, consisting mostly of coiled coils of triple helices. With the advent of molecular biology and biophysical techniques, structural studies of these spectrin 106-amino acid structural domains became approachable. However, one of the difficulties in such an approach is determination of the correct phasing of the structural domains, which may or may not coincide with the phasing of the sequence motifs. Proper identification of the domain phasing is vital to the construction of stable spectrin domains for molecular studies. A previously published phasing shift for Drosophila alpha-spectrin indicated a downstream phase-shift of 26 amino acids for the structural domain (Winograd, E., Hume, D., and Branton, D. (1991) Proc. Natl. Acad. Sci. U. S. A. 88, 10788-10791). Using this phase-shift, we prepared a recombinant spectrin peptide with the sequence from residue 49 to residue 155 of human erythrocyte alpha-spectrin and found this peptide to be unstable relative to other peptides that we prepared. Using several other recombinant alpha-spectrin peptides and following the protease digestion approach, we digested spectrin peptides with elastase and chymotrypsin and analyzed the amino acid sequence of the digestive products. We provide the first experimental evidence in identifying the first amino acid residue of the first spectrin domain in human erythrocyte alpha-spectrin as residue 52 (Ser).

The behavior of L-ascorbic acid in the healing process of dorsal wounds in guinea pigs

The behavior of L-ascorbic acid (AsA) in the healing process of wounds in guinea pigs was investigated by determining AsA and dehydroascorbic acid (DAsA) levels. Dorsal skin wounds of guinea pigs fed AsA-deficient diets for 10 days were surgically induced, and the animals were intraperitoneally supplemented with 0, 0.5, 5, 50 mg/day of AsA for 4 days, respectively. The animals were sacrificed, and the amounts of AsA and DAsA in healing skin wound and intact skin were determined by high-performance liquid chromatography (HPLC). It was found that total AsA levels in the healing wound of the animals in AsA-supplemented groups were almost similar to those in intact skin, respectively. However, DAsA levels in the healing wounds on day 4 of the healing period are significantly higher than those not only in the intact skin but also in the completely regenerated skin on day 14 of the healing period. From these results, it was suggested that the wound healing process was accompanied by the oxidation of AsA, moreover, the reduction of DAsA to AsA did not sufficiently occur in vivo.