Validation and responsiveness of the English version of the Chemotherapy-Induced Alopecia Distress Scale (CADS) in breast cancer patients.

PURPOSE: This study aimed to validate the Chemotherapy-Induced Alopecia Distress Scale (CADS) in a diverse English-speaking population and patients with endocrine treatment-induced alopecia (EIA). OBJECTIVE: Chemotherapy and endocrine therapy commonly cause alopecia in breast cancer patients, leading to significant psychological and social challenges. The CADS was developed to assess the psychosocial impact of alopecia, but its generalizability beyond Korean patients requires further investigation. METHODS: Data from the CHANCE study (NCT02530177), which focused on non-metastatic breast cancer, was used. The cohort included 256 patients, and CADS data were collected at baseline, 6 months after chemotherapy completion, or 12 months after initiating endocrine therapy. The CADS questionnaire comprised 17 items covering physical and emotional health, daily activities, and relationships. Reliability was assessed using Cronbach's alpha, and responsiveness was measured by effect size. RESULTS: The CADS exhibited good reliability, with Cronbach's alpha of 0.91 for the overall score, indicating acceptable internal consistency in both chemotherapy (0.89) and endocrine therapy (0.86) groups. Longitudinal responsiveness was supported by an effect size of 0.49 between decreasing satisfaction with hair growth and increasing emotional distress. Cross-sectional validity was confirmed, with effect sizes of 0.91 and 0.92 for satisfaction with hair growth and emotional and activity domains, respectively. CONCLUSION: The CADS is a valid and responsive tool for assessing the psychosocial impact of chemotherapy-induced alopecia and endocrine treatment-induced alopecia in a diverse Western patient population.

Practices and perspectives on advanced diagnostic and interventional bronchoscopy among pediatric pulmonologists in the United States.

INTRODUCTION: Advanced diagnostic bronchoscopy includes endobronchial ultrasound (EBUS) guided transbronchial lung and lymph node biopsies, CT navigation and robotic bronchoscopy. Interventional bronchoscopy refers to procedures performed for therapeutic purposes such as balloon dilation of the airway, tissue debulking, cryotherapy, removal of foreign bodies and insertion of endobronchial valves [1]. For adult patients, these procedures are standard of care [2, 3]. Despite a lack of formalized training, there are numerous case reports and case series describing the use of advanced diagnostic and interventional bronchoscopy techniques in children. The safety and feasibility of EBUS-TBNA, cryotherapy techniques, endobronchial valves among other techniques have been demonstrated in these publications [1, 4-9]. METHODS: We sought to better understand the current practices and perspectives on interventional and advanced bronchoscopy among pediatric pulmonologists through surveys sent to pediatric teaching hospitals across the United States. RESULTS: We received 43 responses representing 28 programs from 25 states. The highest bronchoscopy procedure volume occurred in the 0-5 years age group. Among our respondents, 31% self-identified as a pediatric interventional/advanced bronchoscopist. 79% believe that advanced and interventional training is feasible in pediatric pulmonology and 77% believe it should be offered to pediatric pulmonary fellows. DISCUSSION: This is the first study to characterize current practices and perspectives regarding advanced diagnostic and interventional bronchoscopy procedures among pediatric pulmonologists in the United States. Pediatric interventional pulmonology (IP) is in its infancy and its beginnings echo those of the adult IP where only certain centers were performing these procedures.

Validation and Responsiveness of the English version of the Chemotherapy-Induced Alopecia Distress Scale (CADS) in Breast Cancer Patients.

Purpose: This study aimed to validate the chemotherapy-induced alopecia distress scale (CADS) in a diverse English-speaking population and patients with endocrine treatment- induced alopecia (EIA). Objective: Chemotherapy and endocrine therapy commonly cause alopecia in breast cancer patients, leading to significant psychological and social challenges. The CADS was developed to assess the psychosocial impact of alopecia, but its generalizability beyond Korean patients requires further investigation. Methods: Data from the CHANCE study ( NCT02530177 ), which focused on non-metastatic breast cancer, was used. The cohort included 256 patients, and CADS data were collected at baseline, six months after chemotherapy completion, or 12 months after initiating endocrine therapy. The CADS questionnaire comprised 17 items covering physical and emotional health, daily activities, and relationships. Reliability was assessed using Cronbach's alpha, and responsiveness was measured by effect size. Results: The CADS exhibited good reliability, with a Cronbach's alpha of 0.91 for the overall score, indicating acceptable internal consistency in both chemotherapy (0.89) and endocrine therapy (0.86) groups. Longitudinal responsiveness was supported by an effect size of 0.49 between decreasing satisfaction with hair growth and increasing emotional distress. Cross-sectional validity was confirmed, with effect sizes of 0.91 and 0.92 for satisfaction with hair growth and emotional and activity domains, respectively. Conclusion: The CADS is a valid and responsive tool for assessing the psychosocial impact of chemotherapy-induced alopecia and endocrine treatment-induced alopecia in a diverse Western patient population.

Associations between participation in family activities and adolescent school problems.

INTRODUCTION: Adolescent risk outcomes related to school issues are widespread, with about 20% parents reporting poor school engagement amongst their youth. Previous literature suggests that adolescents who report strong bonds with their parents are often identified as being less likely to engage in risky behaviours, such as substance use. The current study sought to examine the association between the frequencies of selected family activities and school problems amongst adolescents after adjustments for family connectedness and other characteristics. METHODS: Data were drawn from the National Longitudinal Survey of Youth, 1997. Of the 8984 youth interviewed, 3855 also had a sibling interviewed who met the selection criteria. School problem outcomes measured were suspension occurrence, poor grades and highest grade completed low for age. Independent variables of interest were self-reported frequency of family dinner, fun and religious activities in a typical week. Multivariable logistic models were estimated for each outcome, and multivariable linear probability models were estimated adjusting for family fixed effects. RESULTS: Adjusting for family connectedness, there were significant associations between certain family activities and adolescent school problem measures. However, these results did not remain significant in models with family fixed effects, suggesting that associations could be driven by family-level confounders. DISCUSSION: This study did not find strong evidence of a protective relationship between family activities and school problems. Therefore, it suggested that programme and policymakers be cautious in overstating the importance of family activities in preventing adolescent risk outcomes until true causal relationships can be determined.

Wellness among US adolescents ages 12-17 years.

BACKGROUND: Wellness is a multidimensional construct related to an individual's physical, emotional, intellectual and social well-being. We present estimates of wellness among US adolescents aged 12-17 years and explore how demographic characteristics are associated with wellness. METHODS: All respondents aged 12 to 17 years (n = 34,601) from the 2011-2012 National Survey of Children's Health were included in the sample. Survey items were coded to operationalize an overall wellness score, comprised of four subdimensions (physical, intellectual, emotional and social). RESULTS: The mean adjusted overall wellness score was 30.2 (out of 40). Mean raw subdimensions scores were: social = 3.14 (out of 4), emotional = 4.79 (out of 6), intellectual = 4.80 (out of 8) and physical = 6.57 (out of 8). Older adolescents, those with special health needs, those in lower income families and those whose mother or father report fair-poor mental health status had lower wellness scores. CONCLUSIONS: US adolescents have wellness scores towards the upper or higher end of our scale. Several adolescent and family characteristics were associated with either lower overall wellness and/or lower wellness on multiple subdimensions. Assessing wellness during critical developmental periods of adolescence is a first step towards promoting behaviours that support increased wellness into adulthood.

Correlates of wellness among youth with functional disabilities.

BACKGROUND: The literature is more informative on the impediments to wellness among youth with functional limitations and less instructive on the state of wellness for this population. OBJECTIVE: To explore overall wellness, and each sub-dimension of wellness, in a national sample of youth with functional limitations and to determine how demographic characteristics are associated with wellness. METHODS: Using a previously validated screening instrument, we identify youth with functional limitations aged 12 to 17 represented in the 2011/12 National Survey of Children's Health. Survey items were coded to operationalize an overall wellness score comprised of four sub-dimensions of wellness (i.e., physical, intellectual, emotional, and social). RESULTS: The mean overall wellness score was 26.7 (out of 40) and had an approximate normal distribution. Mean raw scores for each sub-dimension were as follows: social = 2.79 (out of 4; 69.7%); emotional = 4.09 (out of 6; 68.2%); intellectual = 3.79 (out of 8; 47.4%); and physical = 6.30 (out of 8; 78.7%). Lower wellness scores were associated with older age among youth, increasing number of chronic health conditions, lower income, single mother homes, and youth whose mother reported fair or poor mental health status (all p < 0.05). Higher wellness scores were positively associated with mother's education (p < 0.001). CONCLUSIONS: Program planners should consider interventions that target youth with functional limitations shown to be at particular risk for lower overall wellness and promote family involvement and comprehensive supports, including maternal educational attainment, mental health screening, and referral.

Lung transplantation in children following bone marrow transplantation: a multi-center experience.

Allogenic BMT has been successfully performed as a treatment for hematologic diseases with an expected long-term survival. This survival is truncated by respiratory complications including airway obstruction especially BO. Chronic GVHD has been reported to precede almost all cases reported. LTx has become a therapeutic life-saving option for patients with end-stage lung disease that maybe offered for the treatment of GVHD. We report a multi-center experience of pediatric LTx following BMT in 11 patients age- and gender-matched with 11 controls who received LTx for end-stage lung disease secondary to CF. Overall death was 36.4% over a follow-up period of 19 months (range 3-36 months) for the cases and 27.3% for the control group followed for 17 months (range 8-32 months). Median FEV1 one yr post-transplant for the cases was 78% predicted compared with 67.3% predicted for the controls. The median for episodes of infection was comparable at a median of one episode per patient through the entire follow-up period among both groups. Acute rejection episodes were significantly higher in the control group with a median of one episode per patient in the control group compared to none within the cases. Our data suggest that LTx may be a valuable therapeutic option for children with end-stage lung disease post-BMT with comparable survival outcome to that after LTx in children for other indications such as CF. Hospital stay was significantly longer in our case group. Infection rate was comparable between groups albeit type of infection varied. Significantly and of interest is that acute rejection episodes were non-existent in these cases.

Respiratory viral infections within one year after pediatric lung transplant.

To characterize epidemiology and risk factors for respiratory viral infections (RVI) in pediatric lung transplant recipients within the first post-transplant year, a retrospective multicenter study of pediatric lung transplant recipients from 1988 to 2005 was conducted at 14 centers in the United States and Europe. Data were recorded for 1 year post transplant. Associations between RVI and continuous and categorical risk factors were assessed using Wilcoxon's rank-sum and chi(2) tests, respectively. Associations between time to RVI and risk factors or survival were assessed by multivariable Cox proportional hazards models. Of 576 subjects, 79 subjects (14%) had 101 RVI in the first year post transplant. Subjects with RVI were younger than those without RVI (median ages 9.7, 13; P<0.01). Viruses detected included adenovirus (n=25), influenza (n=9), respiratory syncytial virus (n=21), parainfluenza virus (n=19), enterovirus (n=4), and rhinovirus (n=22). In a multivariable model for time to first RVI, etiology other than cystic fibrosis (CF), younger age, and no induction therapy were independently associated with risk of RVI. Cytomegalovirus serostatus and acute rejection were not associated with RVI. RVI was independently associated with decreased 12-month survival (hazard ratio 2.6, 95% confidence interval 1.6-4.4). RVI commonly occurs after pediatric lung transplantation with risk factors including younger age and non-CF diagnosis. RVI is associated with decreased 1-year survival.

Prospective analysis of psychosocial outcomes after breast reconstruction: cross-cultural comparisons of 1-year postoperative results.

Breast reconstruction has been shown to improve quality of life in women following mastectomy for breast cancer. To date, there have been no published prospective reports looking at the effect nationality has on patient quality of life following breast reconstruction. Women from the USA, Sweden and Canada were recruited prior to reconstruction and followed prospectively for 1 year postoperatively. Thirteen centres with 24 plastic surgeons were involved. Preoperatively and 1 year postoperatively, women completed the Short Form-36 questionnaire. Data were analysed using t-tests and analysis of variance. A total of 313 women were followed up. American women who had immediate expander/implant surgery were compared with Swedish patients, whilst Americans who had undergone transverse rectus abdominis myocutaneous (TRAM) flap reconstructions were compared with Canadians. Women benefited from having breast reconstruction, but this improvement was not dependent upon country of origin. Swedish women reported less improvement in one subscale, that of general health, compared with American women (P=0.01). There were no cultural differences detected between Americans and Canadians.

TGF-beta: a crucial component of the pathogenesis of diabetic nephropathy.

In summary, metabolic, hemodynamic, and genetic factors are all important in the development and progression of diabetic nephropathy (33). Recent studies using cell culture techniques and experimental animal models have provided important insight into the role of hyperglycemia in this disease. The nature of the factors directly arising as a consequence of hyperglycemia and the steps involved in diabetic complications are not completely understood. The characteristic lesions of diabetic nephropathy may be intimately related to the effects of high ambient glucose on intracellular signaling events, various growth factors/cytokines, and nonenzymatic glycation of proteins (36). The growth factor TGF-beta has emerged as a key participant in the cascade of events which leads to kidney sclerosis. Increased TGF-beta expression in the kidney in diabetes mellitus mediates the renal actions of high ambient glucose to promote cellular hypertrophy and stimulate extracellular matrix biosynthesis. Neutralizing the actions of TGF-beta with highly specific monoclonal antibodies or with application of antisense technology can effectively prevent the induction of the kidney lesions of diabetes in mice independent of any changes in blood glucose levels. Such maneuvers are crucial for establishing proof-of-concept and Koch's postulates (17), but they are still far removed from clinical applicability. Nevertheless, it is hoped that further studies to elucidate the efficacy of novel interventions to intercept the activity of the renal TGF-beta system will prove useful for effectively halting the progression of diabetic nephropathy.

Complications and patient satisfaction following expander/implant breast reconstruction with and without radiotherapy.

PURPOSE: To compare the rates of complications and patient satisfaction among breast cancer patients treated with mastectomy and tissue expander/implant reconstruction with and without radiotherapy. METHODS AND MATERIALS: As part of the Michigan Breast Reconstruction Outcome Study (MBROS), breast cancer patients undergoing mastectomy with reconstruction were prospectively evaluated with respect to complications, general patient satisfaction with reconstruction, and esthetic satisfaction. Included in this study was a cohort of women who underwent breast reconstruction using an expander/implant (E/I). A subset of these patients also received radiotherapy (RT). At 1 and 2 years postoperatively, a survey was administered which included 7 items assessing both general satisfaction with their reconstruction and esthetic satisfaction. Complication data were also obtained at the same time points using hospital chart review. Radiotherapy patients identified in the University of Michigan Radiation Oncology database that underwent expander/implant reconstruction but not enrolled in the MBROS study were also added to the analysis. RESULTS: Eighty-one patients underwent mastectomy and E/I reconstruction. Nineteen patients received RT and 62 underwent reconstruction without RT. The median dose delivered to the reconstructed breast/chest wall, including boost, was 60.4 Gy (range, 50.0-66.0 Gy) in 1.8- to 2.0-Gy fractions. With a median follow-up of 31 months from the date of surgery, complications occurred in 68% (13/19) of the RT patients compared to 31% (19/62) in the no RT group (p = 0.006). Twelve of 81 patients (15%) had a breast reconstruction failure. Reconstruction failure was significantly associated with experiencing a complication (p = 0.0001) and the use of radiotherapy (p = 0.005). The observed reconstruction failure rates were 37% (7/19) and 8% (5/62) for patients treated with and without radiotherapy, respectively. Tamoxifen was associated with a borderline risk of complications (p = 0.07) and a significant risk of reconstruction failure (p = 0.01). Sixty-six patients of the study group completed the satisfaction survey; 15 patients did not. To offset potential bias for patients not completing the survey, we analyzed satisfaction data assuming "dissatisfaction" scores for surveys not completed. In the analysis of patients with unilateral E/I placement, reconstruction failure was significantly associated with a lower general satisfaction (p = 0.03). Ten percent of patients experiencing a reconstruction failure were generally satisfied compared to 23% who completed E/I reconstruction. In addition, tamoxifen use was associated with a significantly decreased esthetic satisfaction (p = 0.03). Radiotherapy was not associated with significantly decreased general or esthetic satisfaction. CONCLUSION: Irradiated patients had a higher rate of expander/implant reconstruction failure and complications than nonirradiated patients. Despite these differences, our pilot data suggest that both general satisfaction and patient esthetic satisfaction were not significantly different following radiotherapy compared to patients who did not receive RT. Although statistical power was limited in the present study and larger patient numbers are needed to validate these results, this study suggests comparable patient assessment of cosmetic outcome with or without radiotherapy in women who successfully complete expander/implant reconstruction.

Prospective analysis of psychosocial outcomes in breast reconstruction: one-year postoperative results from the Michigan Breast Reconstruction Outcome Study.

In the past decade, changing attitudes toward breast reconstruction among both patients and providers have led a growing number of women to seek breast reconstruction after mastectomy. Although investigators have documented the psychological, social, emotional, and functional benefits of breast reconstruction, little research has evaluated the effects of procedure choice on these outcomes. The current study prospectively evaluated and compared psychosocial outcomes for three common options for mastectomy reconstruction: tissue expander/implant, pedicle TRAM, and free TRAM techniques. In a prospective cohort design, patients undergoing postmastectomy reconstruction for the first time with expander/implant, pedicle TRAM, or free TRAM procedures were recruited from 12 centers and 23 plastic surgeons in the United States and Canada. Before reconstruction and at 1 year after reconstruction, patients were evaluated by a battery of questionnaires consisting of both generic and condition-specific surveys. Outcomes assessed included emotional well-being, vitality, general mental health, social functioning, functional well-being, social well-being, and body image. Baseline (preoperative) scores and the change in scores (the difference between postoperative and preoperative scores) were compared across procedure types using t tests and analysis of covariance. Preoperative and 1-year postoperative surveys were obtained from 273 patients. Procedure type was reported in 250 patients, of whom 56 received implant reconstructions, 128 pedicle TRAM flaps, and 66 free TRAM flaps. A total of 161 immediate and 89 delayed reconstructions were performed. Among women receiving immediate reconstruction, significant improvements were observed in all psychosocial variables except body image. However, no significant effects of procedure type on these changes over time existed. Similarly, delayed reconstruction patients had significant increases in emotional well-being, vitality, general mental health, functional well-being, and body image. Although the choice of reconstructive technique did not significantly impact most of these outcomes, significant differences existed among procedure types for three psychosocial subscales. Patients undergoing delayed expander/implant reconstructions reported greater improvements in vitality and social well-being relative to women receiving delayed TRAM procedures. By contrast, delayed TRAM patients noted significantly greater gains in body image compared with women choosing delayed expander-implant reconstruction. The authors conclude that both immediate and delayed breast reconstructions provide substantial psychosocial benefits for mastectomy patients. Although the choice of reconstructive procedure does not seem to significantly affect improvements in psychosocial status with immediate reconstruction, our data suggest that procedure type does have a significant effect on gains in vitality and body image for women undergoing delayed reconstruction.

FRAP DNA-dependent protein kinase mediates a late signal transduced from ultraviolet-induced DNA damage.

Ultraviolet radiation induces signal transduction at both early (<6 h) and late (>6 h) times after exposure. The inflammatory and immunosuppressive cytokine tumor necrosis factor alpha is induced at late times, and is induced by ultraviolet-induced DNA damage, as defects in DNA repair increase, and enhanced photoproduct repair reduces, tumor necrosis factor alpha expression. Here we show that late tumor necrosis factor alpha gene expression is sensitive to rapamycin, implicating FKBP12-rapamycin-associated protein, a member of the DNA protein kinase family, as a signal transducer of ultraviolet-induced DNA damage. FKBP12-rapamycin-associated protein was localized in the nucleus of keratinocytes and its level was increased following ultraviolet irradiation. Immuno- precipitated FKBP12-rapamycin-associated protein was stimulated by ultraviolet-irradiated DNA to phosphorylate p53 in vitro, and in vivo rapamycin reduced ultraviolet induction of p53 by 20%. Rapamycin further inhibited the ultraviolet-induced phosphorylation of the FKBP12-rapamycin-associated protein downstream target kinase p70S6K. In mice, topical application of rapamycin before ultraviolet exposure protected against suppression of the contact hypersensitivity that is a hallmark of ultraviolet-induced cytokine gene expression. These results demonstrate that the FKBP12-rapamycin-associated DNA protein kinase transduces the signal of ultraviolet-induced DNA damage into production of immunosuppressive cytokines at late times after ultraviolet irradiation.

The urine/plasma electrolyte ratio: a predictive guide to water restriction.

Patients with hypotonic hyponatremia are encountered commonly in the general practice of medicine. Nearly all strategies for the management of subacute or chronic hyponatremia call for some amount of water restriction. The considerations for such a prescription have not been addressed in the literature. We describe therefore a simple approach grounded in the physiology of electrolyte-free water clearance that can be used at the bedside.

HMO direct costs and health care resources use after implementation of a monthly limit on sumatriptan.

The health care costs and resource use of patients with migraine before and after a quantity limit on sumatriptan was introduced in an HMO were compared. A longitudinal, retrospective review of a medical claims database and a pharmacy claims database was conducted for two six-month periods before and after a monthly limit (four tablets or injections) on sumatriptan reimbursement was instituted at an independent practice association-model HMO in February 1997. Patients with at least one medical claim with a diagnosis code for migraine or at least two pharmacy claims for sumatriptan, methysergide, ergotamine, dihydroergotamine, or an ergotamine combination product in 1996 or 1997 were eligible for inclusion. A total of 557 patients were included in the analysis. Migraine-related medical costs and total medical costs increased 1.5% and 24.4%, respectively; neither change was statistically significant. Physician office visits related to migraine increased by 7.8%. The number of hospital admissions for the cohort increased from three to five, but hospital costs decreased by 55.0%. The overall costs of medications for migraine therapy decreased by 4.5%. There was an 8.2% increase in prescriptions for drugs to treat migraine but a 40.0% decrease in their cost, primarily because of decreased sumatriptan use. There was a 33.9% increase in prescriptions for medications that could be used as prophylaxis for migraine and a 49.6% increase in their cost. Implementation of a monthly limit on sumatriptan decreased an HMO's pharmacy costs but did not significantly alter migraine-related direct medical costs and health care resource use of patients with migraine.

The utility of decision support, clinical guidelines, and financial incentives as tools to achieve improved clinical performance.

BACKGROUND: Whether one seeks to reduce inappropriate utilization of resources, improve diagnostic accuracy, increase utilization of effective therapies, or reduce the incidence of complications, the key to change is physician involvement in change. Unfortunately, a simple approach to the problem of inducing change in physician behavior is not available. COMPREHENSIVE CLINICAL GUIDELINES: There is a generally accepted view that expert, best-practice guidelines will improve clinical performance. However, there may be a bias to report positive results and a lack of careful analysis of guideline usage in routine practice in a "postmarketing" study akin to that seen in the pharmaceutical industry. FINANCIAL INCENTIVES: Systems that allow the reliable assessment of quality of outcomes, efficiency of resource utilization, and accurate assessment of the risks associated with the care of given patient populations must be widely available before deciding whether an incentive-based system for providing the full range of medical care is feasible. DECISION SUPPORT: Decision support focuses on providing information, ideally at the "point of service" and in the context of a particular clinical situation. Rules are self-imposed by physicians and are therefore much more likely to be adopted. CONCLUSION: As health care becomes corporatized, with increasing numbers of physicians employed by large organizations with the capacity to provide detailed information on the nature and quality of clinical care, it is possible that properly constructed guidelines, appropriate financial incentives, and robust forms of decision support will lead to a physician-led, process improvement approach to more rational and affordable health care.

Quantitative studies of human urinary excretion of uropontin.

Uropontin is the urinary form of osteopontin, an aspartic acid-rich phosphorylated glycoprotein. Uropontin has been previously shown to be a potent inhibitor of the nucleation, growth and aggregation of calcium oxalate crystals and the binding of these crystals to renal epithelial cells. Quantitative data defining the excretion of this protein are necessary to determine its role in urinary stone formation. In the present studies, we determined uropontin excretion rates of normal humans. Urine samples were obtained under conditions of known dietary intake from young adult human volunteers with no history, radiographic or laboratory evidence of renal disease. Urinary concentrations of uropontin were measured by a sensitive ELISA employing an affinity purified polyclonal antiserum to uropontin. Thirteen normal subjects ingested a constant diet providing 1 gram of calcium, 1 gram of phosphorus, 150 mEq of sodium and 1 gram of protein per kilogram of body wt per day during an eight day study period. The relationship of urinary volume to uropontin excretion was assessed by varying fluid intake on the last four days of the study to change the mean urine volume/24 hr by > 500 ml. Urine collected in six hour aliquots for eight days was analyzed for uropontin by ELISA, and for calcium, and creatinine. Daily uropontin excretion of 13 individual subjects was 3805 +/- 1805 micrograms/24 hr (mean +/- 1 SD). The mean urinary levels (1.9 micrograms/ml) detected in the present study are sufficient for inhibition of crystallization; our previous studies have demonstrated that the nucleation, growth and aggregation of calcium oxalate crystals and their binding to renal cells in vitro are inhibited by this concentration of purified uropontin. In contrast to the regular pattern of diurnal variation of calcium excretion seen in most subjects, uropontin excretion showed no regularity of diurnal variation and was not directly related to either calcium or creatinine excretion or changes in urinary volume. However, uropontin concentration varied inversely with urine volume (P < or = 0.001), so that the highest uropontin concentrations occurred when urine volume was the lowest. We conclude that the physiologic characteristic of an inverse relationship of uropontin concentration to urine volume favors protection from urinary crystallization of calcium oxalate by uropontin. Our quantitative definition of urinary uropontin excretion of normal adults provides the basis for the evaluation of uropontin excretion by individuals who have formed urinary stones.