Increasing Continuous Glucose Monitoring Use for Non-Hispanic Black and Hispanic People With Type 1 Diabetes: Results From the T1D Exchange Quality Improvement Collaborative Equity Study

Despite the benefits of continuous glucose monitoring (CGM), there is lower use of this technology among non-Hispanic Black and Hispanic people with type 1 diabetes compared with their non-Hispanic White counterparts. The T1D Exchange Quality Improvement Collaborative recruited five endocrinology centers to pilot an equity-focused quality improvement (QI) study to reduce racial inequities in CGM use. The centers used rapid QI cycles to test and expand interventions such as provider bias training, translation of CGM materials, provision of CGM education in multiple languages, screening for social determinants of health, and shared decision-making. After implementation of these interventions, median CGM use increased by 7% in non-Hispanic White, 12% in non-Hispanic Black, and 15% in Hispanic people with type 1 diabetes. The gap between non-Hispanic White and non-Hispanic Black patients decreased by 5%, and the gap between non-Hispanic White and Hispanic patients decreased by 8%.

Quality Tool School: Improving the Delivery of Quality Improvement Education in a Children's Hospital

Background

In 2013, Nationwide Children's Hospital's (NCH) Quality Tool School (QTS) was created as an initial Quality Improvement educational series, composed of three separate classes, totaling 5.5 hours of hands-on QI training. QTS complemented the NCH 40-hour Quality Improvement Essentials course.

Methods

Over 10 years, the series went through three phases of aims: Phase 1: develop and implement three core courses (Project Tools, Excel, and Control Charts); Phase 2: have participants complete the entire series of all three classes; Phase 3: have participants who complete the entire series of all three classes demonstrate the application of learning through involvement in a quality improvement project.

Results

Since initiation, QTS has provided an educational entry point for 1428 NCH employees to participate in QI projects and teams. QTS has shown statistically significant improvement in 2 of the 3 principal aims. The Phase 1 metric of average monthly one-class participation completion percentage showed a statistically significant centerline shift from 9 to 16 students in October 2018. The Phase 3 metric Percentage of QTS participants completing the QTS series of classes and then participating in a QI team began in 2016 with a baseline of 42%. A centerline shift from 42% to 63% occurred in Q4 2018.

Conclusions

QTS can provide QI education to healthcare system employees using limited resources. Organizations that strategically integrate a culture of QI into core beliefs can realize substantial improvement gains.

Quality improvement methodology can reduce hospitalisation for abscess management

BACKGROUND

Abscesses are a common reason for ED visits. While many are drained in the ED, some require drainage in the operating room (OR). We observed that a higher percentage of patients at our institution in Columbus, Ohio, were admitted to the hospital with abscesses for incision and drainage (I&D) in the OR than other institutions, including paediatric institutions. Our aim was to decrease hospitalisations for abscess management.

METHODS

A multidisciplinary team convened to decrease hospitalisation for patients with abscesses and completed multiple 'Plan-Do-Study-Act' cycles, including increasing I&Ds performed in the ED. Other interventions included implementation of a clinical pathway, training of procedure technicians (PT), updating the electronic medical record (EMR), credentialing advanced practice nurses in sedation and individual follow-up with providers for admitted patients. Data were analysed using statistical process control charts. Gross average charges were assessed.

RESULTS

Admissions for I&D decreased from 26.3% to 13.7%. Abscess drainage in the ED improved from 79.3% to 96.5%. Mean length of stay decreased from 19.5 to 11.5 hours for all patients. Patients sedated increased from 3.3% to 18.2%. The number of repeat I&Ds within 30 days decreased from 4.3% to 1.7%.

CONCLUSION

We decreased hospitalisations for abscess I&D by using quality improvement methodology. The most influential intervention was an initiative to increase I&Ds performed in the ED. Additional interventions included expanded training of PTs, implementation of a clinical pathway, updating the EMR, improving interdepartmental communication and increasing sedation providers.

Achieving Equity in Diabetes Research: Borrowing From the Field of Quality Improvement Using a Practical Framework and Improvement Tools

There are limited tools to address equity in diabetes research and clinical trials. The T1D Exchange has established a 10-step equity framework to advance equity in diabetes research. Herein, the authors outline this approach and expand on its practical application.

Increasing Insulin Pump Use Among 12- to 26-Year-Olds With Type 1 Diabetes: Results From the T1D Exchange Quality Improvement Collaborative

Insulin pump therapy in pediatric type 1 diabetes has been associated with better glycemic control than multiple daily injections. However, insulin pump use remains limited. This article describes an initiative from the T1D Exchange Quality Improvement Collaborative aimed at increasing insulin pump use in patients aged 12-26 years with type 1 diabetes from a baseline of 45% in May 2018 to >50% by February 2020. Interventions developed by participating centers included increasing in-person and telehealth education about insulin pump technology, creating and distributing tools to assist in informed decision-making, facilitating insulin pump insurance approval and onboarding processes, and improving clinic staff knowledge about insulin pumps. These efforts yielded a 13% improvement in pump use among the five participating centers, from 45 to 58% over 22 months.

Implementation of a Pharmacist-Led Antimicrobial Time-Out for Medical-Surgery Services in an Academic Pediatric Hospital

OBJECTIVE

This report describes a quality improvement initiative to implement a pharmacist-led antimicrobial time-out (ATO) in a large, freestanding pediatric hospital. Our goal was to reach 90% ATO completion and documentation for eligible patients hospitalized on general pediatric medicine or surgery services.

METHODS

A multidisciplinary quality improvement team developed an ATO process and electronic documentation tool. Clinical pharmacists were responsible to initiate and document an ATO for pediatric medicine or surgery patients on or before the fifth calendar day of therapy. The quality improvement team educated pharmacists and physicians and provided ATO audit and feedback to the pharmacists. We used statistical process control methods to track monthly rates of ATO completion retrospectively from October 2017 through March 2018 and prospectively from April 2018 through April 2019. Additionally, we retrospectively evaluated the completion of 6 data elements in the ATO note over the final 12-month period of the study.

RESULTS

Among 647 eligible antimicrobial courses over the 19-month study period, the mean monthly documentation rate increased from 54.6% to 83.5% (p < 0.001). The mean ATO documentation rate increased from 32.8% to 74.2% (p < 0.001) for the pediatric medicine service and from 65.0% to 88.1% for the pediatric surgery service (p = 0.006). Among 302 notes assessed for completeness, 35.8% had all the required data fields completed. A tentative antimicrobial stop date was the data element completed least often (49.3%).

CONCLUSIONS

We implemented a pharmacist-led ATO, highlighting the role pharmacists play in antimicrobial stewardship. Additional efforts are needed to further increase ATO completion rates and to define treatment duration.

1331. Reducing Inpatient Antimicrobial Treatment Duration for Febrile Infants through Implementation of Rapid Diagnostic Testing and Clinical Risk Definition

Background

The management approach to febrile infants remain challenging. Despite new advances in rapid diagnostic testing, febrile infants with a viral infection could receive prolonged antimicrobial treatment due to concerns for co-existing serious bacterial infection (SBI). We sought to decrease the duration of antibiotic treatment in febrile infants less than 8 weeks of age hospitalized on inpatient infectious disease service following sepsis evaluation, who have enterovirus, parechovirus, or respiratory viruses detected, from average 30 hours to 24 hours and sustain for six months.

Figure 1. Antibiotic Treatment Duration of Infants Underfoing Evaluation for Sepsis

Figure 2. Length of Stay in Infants Underfoing Sepsis Evaluation

Methods

A new management guideline that defined “low-risk” infants, as well as inclusion and exclusion criteria, was created to monitor the accurate duration of parenteral treatment and length of hospitalization. Respiratory viruses were detected by a multiplex PCR assay. We created a QlikSense App for further clinical characterization of patients and follow-up. This management guideline was adapted as a quality improvement division initiative. Control charts were used to assess the impact of the interventions.

Figure 3. Readmissions in Infants Underfoing Sepsis Evaluation

Results

The management guideline was developed and implemented by pediatric infectious disease faculty. Febrile infants < 8 weeks of age were included if they had both documented viral infections and sepsis evaluation. 178 infants were admitted with fevers in 2018 and 148 infants were admitted in 2019. The mean inpatient antibiotic treatment duration decreased from 27.7 hours in 2018 to 24.9 hours in 2019 (P > 0.05) (Figure 1). There was no significant difference in length of hospitalization or 30-day readmission rates (Figure 2 and 3). There was no reported readmission for SBI.

Conclusion

Antibiotic treatment could be discontinued in clinically stable infants with a documented viral infection after 24 hours of negative blood, CSF, and urine bacterial culture incubation so as not to receive unnecessary prolonged inpatient treatment that may increase side effects. In addition to possible decreased treatment side effects our protocol led to decreased patient care costs with no documented changes in readmission rates.

Disclosures

Octavio Ramilo, MD, Bill & Melinda Gates Foundation (Grant/Research Support)Janssen (Grant/Research Support, Advisor or Review Panel member)Medimmune (Grant/Research Support)Merck (Advisor or Review Panel member)NIH/NIAID (Grant/Research Support)Pfizer (Consultant, Advisor or Review Panel member)Sanofi/Medimmune (Consultant, Advisor or Review Panel member)

Triage Standing Orders Decrease Time to Antibiotics in Neonates in Pediatric Emergency Department

INTRODUCTION

Infants aged 0 days to 28 days are at high risk for serious bacterial infection and require an extensive evaluation, including blood, urine, and cerebrospinal fluid cultures, and admission for empiric antibiotics. Although there are no guidelines that recommend a specific time to antibiotics for these infants, quicker administration is presumed to improve care and outcomes. At baseline, 19% of these infants in our emergency department received antibiotics within 120 minutes of arrival, with an average time to antibiotics of 192 minutes. A quality improvement team convened to increase our percentage of infants who receive antibiotics within 120 minutes of arrival.

METHODS

The team evaluated all infants aged 0 days to 28 days who received a diagnostic evaluation for a serious bacterial infection and empiric antibiotics in our emergency department. A nurse-driven team implemented multiple Plan-Do-Study-Act cycles to improve use of triage standing orders and improve time to antibiotics. Data were analyzed using statistical process control charts.

RESULTS

Through use of triage standing orders and multiple educational interventions, the team surpassed initial goals, and 84% of the infants undergoing a serious bacterial infection evaluation received antibiotics within 120 minutes of ED arrival. The average time to antibiotics improved to 74 minutes.

DISCUSSION

The use of triage standing orders improves time to antibiotics for infants undergoing a serious bacterial infection evaluation. Increased use, associated with nurse empowerment to drive the flow of these patients, leads to a joint-responsibility model within the emergency department. The cultural shift to allow nurse-initiated work-ups leads to sustained improvement in time to antibiotics.

The diabetes care index: A novel metric to assess delivery of optimal type 1 diabetes care

OBJECTIVES

The American Diabetes Association (ADA) and the International Society for Pediatric and Adolescent Diabetes (ISPAD) have outlined standards for best practices in providing optimal diabetes care to children with type 1 diabetes (T1D). Our objectives were to design a metric that evaluated delivery of optimal diabetes care and to use this metric to drive improvement within our diabetes program.

METHODS

Using published guidelines, we identified 11 elements of optimal diabetes care that should be reliably delivered at our institution as standard-of-care. We utilized our electronic medical record to aid in data collection and to notify staff when to deliver specific care elements (eg, lipid collection, depression screening, etc.). We designed the T1D Care Index (T1DCI), a metric which aggregates missed opportunities to deliver elements of optimal diabetes care over a given period into a cumulative score, with a lower T1DCI reflecting better care delivery and improved program performance.

RESULTS

Tracking the T1DCI permitted recognition of areas to focus on quality improvement efforts, guided interventions to improve processes for care delivery, and helped determine the allocation of time and resources. Interventions resulted in improvement of care delivery across some elements of care. Overall, we observed a 26% reduction in the T1DCI after 12 months of utilization.

CONCLUSIONS

The T1DCI is a powerful metric to evaluate the ability of our diabetes program to standardize, quantify, and monitor delivery of optimal diabetes care to children with T1D, and to drive our program toward zero missed opportunities for quality care delivery.

Validation of a risk screening tool for pediatric type 1 diabetes patients: a predictor of increased acute health care utilization

Background Both psychosocial and socioeconomic risk factors contribute to poor glycemic control (GC). Previous research has identified that diabetes care behaviors are generally 'set' by late childhood, further highlighting the importance of psychosocial screening and intervention in the early course of disease management. The purpose of the current study was to determine whether this brief risk assessment tool is associated with GC and acute health care (HC) utilization, and to evaluate the discriminatory utility of the tool for predicting poor outcomes. Methods This was a retrospective cohort design in which we compared risk assessment scores with health outcomes at 6, 12, and 18 months after new-onset type 1 diabetes diagnosis for 158 patients between 2015 and 2017. The two primary outcome variables were GC and acute HC utilization. Results Our data demonstrate that the greatest utility of the tool is for predicting increased acute HC utilization. It was most useful in differentiating between patients with vs. without any acute HC utilization, with excellent discriminatory ability (area under the receiver operator characteristic curve [AUC] = 0.93), sensitivity (90%), and specificity (97%). Conclusions Knowledge of the risk category in addition to identification of individual risk factors within each domain allows for not only clear treatment pathways but also individualized interventions. The risk assessment tool was less effective at differentiating patients with poor GC; however, the tool did have high specificity (83%) for predicting poor GC at 18 months which suggests that the tool may also be useful for predicting patients at risk for poor GC.

Urine Culture Follow-up and Antimicrobial Stewardship in a Pediatric Urgent Care Network

BACKGROUND AND OBJECTIVES

Empiric antibiotic therapy for presumed urinary tract infection (UTI) leads to unnecessary antibiotic exposure in many children whose urine culture results fail to confirm the diagnosis. The objective of this quality improvement study was to improve follow-up management of negative urine culture results in the off-campus urgent care network of Nationwide Children's Hospital to reduce inappropriate antibiotic exposure in children.

METHODS

A multidisciplinary task force developed and implemented a protocol for routine nurse and clinician follow-up of urine culture results, discontinuation of unnecessary antibiotics, and documentation in the electronic medical record. Monthly antibiotic discontinuation rates were tracked in empirically treated patients with negative urine culture results from July 2013 through December 2015. Statistical process control methods were used to track improvement over time. Fourteen-day return visits for UTIs were monitored as a balancing measure.

RESULTS

During the study period, 910 patients received empiric antibiotic therapy for UTIs but had a negative urine culture result. The antibiotic discontinuation rate increased from 4% to 84%, avoiding 3429 (40%) of 8648 antibiotic days prescribed. Among patients with discontinued antibiotics, none was diagnosed with a UTI within 14 days of the initial urgent care encounter.

CONCLUSIONS

Implementation of a standard protocol for urine culture follow-up and discontinuation of unnecessary antibiotics was both effective and safe in a high-volume pediatric urgent care network. Urine culture follow-up management is an essential opportunity for improved antimicrobial stewardship in the outpatient setting that will affect many patients by avoiding a substantial number of antibiotic days.

Bringing home the right to food in Canada: challenges and possibilities for achieving food security

We offer a critique of Canada's approach to domestic food security with respect to international agreements, justiciability and case law, the breakdown of the public safety net, the institutionalisation of charitable approaches to food insecurity, and the need for ‘joined-up’ food and nutrition policies. We examined Canada's commitments to the right to food, as well as Canadian policies, case law and social trends, in order to assess Canada's performance with respect to the human right to food. We found that while Canada has been a leader in signing international human rights agreements, including those relating to the right to food, domestic action has lagged and food insecurity increased. We provide recommendations for policy changes that could deal with complex issues of state accountability, social safety nets and vulnerable populations, and joined-up policy frameworks that could help realise the right to adequate food in Canada and other developed nations.

Impact of a deep saturation dive on semen quality

The demonstration dive 'Aurora' has provided an opportunity to study the impact of extreme hyperbaric conditions on male fertility. This operation involved a 33-day diving programme during which divers were exposed to a maximum pressure of 4.6 Mega Pascals (Mpa) for 7 days. At days - 4, + 27, + 34, + 82 and + 263 relative to the initiation of the dive, semen samples were analysed to determine the quality of spermatogenesis and the functional competence of the spermatozoa. A dramatic fall in semen quality was observed in association with the dive and by day + 82 the potential fertility of the men was seriously compromised as evidenced by oligoasthenoteratozoospermic semen profiles and the poor fertilizing potential of the spermatozoa. These studies indicate, for the first time, that the severe hyperbaric conditions associated with deep saturation dives have a profound effect on male reproductive function.

Relationships between biochemical markers for residual sperm cytoplasm, reactive oxygen species generation, and the presence of leukocytes and precursor germ cells in human sperm suspensions

In this study, we have examined the relationship between creatine phosphokinase (CPK), a biochemical measure of human sperm quality (Huszar et al., 1988a,b, 1990; Huszar and Vigue, 1994), and a marker for the presence of residual cytoplasm in human spermatozoa, glucose-6-phosphate dehydrogenase (G6PDH). We then determined whether the diagnostic potential of these enzymes was related to the capacity of the sperm suspensions to generate reactive oxygen species (ROS) and/or the presence of leukocytes and precursor germ cells. Across the data set as a whole, G6PDH and CPK were highly correlated with each other and, to a lesser extent, with the generation of ROS. Contamination of the sperm suspensions with leukocytes might have contributed to these associations, since the presence of such cells was also significantly correlated with CPK, G6PDH, and ROS. However, even after the leukocytes had been carefully removed, G6PDH was still highly correlated with CPK (r = 0.794), indicating that both criteria were providing similar information of the cytosolic component of human sperm suspensions. In the absence of leukocyte contamination, CPK and G6PDH activities were also correlated with the presence of precursor germ cells, and this association may, in part, explain the diagnostic value of these criteria. An additional component of their prognostic value may be reflected in the statistically significant association observed between G6PDH activity and ROS generation. A possible mechanism for such an association is suggested, which should be amenable to experimental verification.

Analysis of the extent to which sperm movement can predict the results of ionophore-enhanced functional assays of the acrosome reaction and sperm-oocyte fusion

This study has examined the extent to which the information generated by ionophore-enhanced bioassays of the acrosome reaction and sperm-oocyte fusion might be predicted from the computer-aided analysis of sperm motility. Strong correlations (r approximately 0.7) were observed between specific components of sperm movement in semen and the potential for A23187-induced sperm-oocyte fusion, generating a stepwise regression coefficient of R = 0.663 on the bais of two criteria, percentage progressive motility and amplitude of sperm lateral head displacement (ALH). The movement characteristics of the spermatozoa recovered from the Percoll gradients gave an even higher R value of 0.838 on the basis of four variables (percentage rapid, average path velocity, straightness and ALH). In contrast, the ability of human spermatozoa to undergo acrosome reaction in response to A23187 exhibited a limited correlation with sperm movement, whether these measurements were made in the original semen sample or following Percoll purification (R approximately 0.4). These results have diagnostic implications, since sperm-oocyte fusion and the acrosome reaction clearly differ in their relative dependence on sperm motility. In practical terms, it should be noted that the computer-aided analysis of sperm movement was shown to provide up to 70% of the information generated by the more laboured assessment of sperm-oocyte fusion.

Leukocytic infiltration into the human ejaculate and its association with semen quality, oxidative stress, and sperm function

Immunocytochemical techniques have been used to monitor the size and composition of the leukocyte population in unfractionated human semen samples and sperm populations generated by Percoll gradient centrifugation. The characteristics of the leukocyte population have then been related to the quality of the semen profile, the production of reactive oxygen species, and the functional competence of the spermatozoa. A majority (97%) of the ejaculates examined contained leukocytes, and in 82.4% the major cell type was the granulocyte. Small numbers of T cells, B cells, and monocytes/macrophages could also be found in 62%, 43%, and 21% of samples, respectively, and patients were occasionally identified in whom one of these cell types became the predominant leukocyte species. Although a subpopulation of patients was identified in whom the infiltration of multiple leukocyte species was positively correlated with the concentrations of spermatozoa and precursor germ cells in semen, in general, the presence of leukocytes, to the point of leukocytospermia, did not significantly influence any component of the semen profile. Similarly, the fertilizing potential of the washed spermatozoa, as assessed by in vitro tests of the acrosome reaction and sperm-oocyte fusion, was not correlated with the concentration of seminal leukocytes. In contrast, the carryover of leukocytes into the washed sperm preparations profoundly influenced the fertilizing potential of the spermatozoa via mechanisms that were associated with the production of reactive oxygen species. These results have implications for the diagnostic significance of leukocyte contamination in the context of male infertility and assisted conception.

Relationship between iron-catalysed lipid peroxidation potential and human sperm function

The relationship between lipid peroxidation and the functional competence of human spermatozoa has been investigated in a cohort of 31 infertility patients. Lipid peroxidation was assessed using a sensitive fluorometric assay for the generation of malondialdehyde in response to the presence of a ferrous ion promoter. Sperm function was evaluated by monitoring the movement characteristics of these cells and their capacity for sperm-oocyte fusion. Each sample was separated into high- and low-density sperm populations on discontinuous, two-step (40%:80%), Percoll gradients prior to analysis. The way in which individual ejaculates fractionated on these gradients was highly positively correlated (P < 0.001) with the lipoperoxidation status of the spermatozoa; the greater the potential for malondialdehyde generation, the higher the proportion of cells entering the low density region of the gradients. The lipoperoxidation potential of the freshly prepared spermatozoa was also highly predictive (P = 0.0001) of their capacity for movement at 3 and 24 h and their ability to exhibit sperm-oocyte fusion in response to the ionophore A23187. The potential for malondialdehyde generation in the 40% and 80% Percoll fractions was positively associated with midpiece abnormalities in the spermatozoa. These results emphasize the importance of lipid peroxidation in the pathophysiology of male infertility and suggest a mechanism by which such damage might arise.

Use of a xanthine oxidase free radical generating system to investigate the cytotoxic effects of reactive oxygen species on human spermatozoa

The reaction between xanthine and xanthine oxidase results in the univalent and divalent reduction of dioxygen to generate superoxide (O2-.) and hydrogen peroxide (H2O2), respectively. With the aid of this system, the direct effect of reactive oxygen species (ROS) on human sperm function has been investigated. A protocol involving the addition of xanthine oxidase to the reaction mixture at 0 and 15 min resulted in a loss of motility involving every component of sperm movement examined. Lower doses of xanthine oxidase, which did not influence sperm motility, were also found to suppress the competence of human spermatozoa to exhibit oocyte fusion in response to the ionophore, A23187. The reactive oxygen species responsible for the disruption of human sperm function was not influenced by the presence of superoxide dismutase (SOD) or scavengers of hypochlorous acid or hydroxyl radicals. However, the cytotoxic species was shown to be extremely stable and could be completely eliminated by catalase, which selectively eliminates H2O2. Confirmation that it is H2O2, and not O2-., which is cytotoxic to human spermatozoa was obtained in studies in which the direct addition of this oxidant was shown to influence both the movement of human spermatozoa and their competence for oocyte fusion. These results carry implications for the diagnosis of defective sperm function and the design of optimized culture media for the treatment of male factor infertility.

Development of a technique for monitoring the contamination of human semen samples with leukocytes

OBJECTIVE

To determine whether receptors for the N-formyl chemotactic peptide, FMLP, exist on the surface of human spermatozoa and regulate reactive oxygen species generation by these cells.

DESIGN

Chemiluminescent analysis of reactive oxygen species generation by suspensions of human spermatozoa before and after removal of leukocytes using a magnetic cell separation technique.

SETTING

Academic Research Institute.

PATIENTS

Unselected male volunteers.

RESULTS

Human sperm suspensions responded to FMLP and phorbol ester (PMA) with a burst of reactive oxygen species production. Autoradiographic analyses employing 3H FMLP and chemiluminescence studies involving the selective removal of leucocytes with anti-CD 45-coated magnetic beads demonstrated that the FMLP responses were because of leukocyte contamination. In contrast, reactive oxygen species production in response to PMA appeared to reflect the oxidant-generating capacity of both leukocytes and spermatozoa.

CONCLUSION

The only cells present in the human ejaculate possessing detectable receptors for FMLP and capable of generating reactive oxygen species in response to this reagent come from the leukocyte population. Luminol-dependent, FMLP-induced, chemiluminescence provides a rational basis for monitoring the presence of leukocytes in suspensions of human spermatozoa.

Enhanced detection of reactive oxygen species produced by human spermatozoa with 7-dimethyl amino-naphthalin-1, 2-dicarbonic acid hydrazide

A new chemiluminescence technique has been assessed for the detection of reactive oxygen species generated by purified populations of human sperm. This revised protocol involves the use of horse-radish peroxidase (HRP) in combination with a luminol analogue, 7-dimethyl amino-naphthalin-1,2-dicarbonic acid hydrazide (DNDH), that exhibits two-three times the quantal efficiency of luminol itself. The chemiluminescent signal generated with these reagents was significantly (P less than 0.001) greater than that obtained with the conventional luminol-based methodology for both the steady-state situation and following stimulation of the sperm with PMA and A23187. Dose-response analyses indicated that the DNDH/HRP chemiluminescence system could give linear standard curves with hydrogen peroxide concentrations into the nmol l-1 range. In contrast, the exponential rise in chemiluminescence recorded with luminol was not observed until hydrogen peroxide concentrations exceeded 10 mumol l-1. It is concluded that the enhanced sensitivity of the DNDH/HRP system to low levels of hydrogen peroxide should facilitate the application of chemiluminescent techniques to the diagnosis of oxidative stress in cases of male infertility.

Differential contribution of leucocytes and spermatozoa to the generation of reactive oxygen species in the ejaculates of oligozoospermic patients and fertile donors

Cells isolated from the ejaculates of a high proportion of patients exhibiting oligozoospermia are characterized by generation rates of reactive oxygen species that considerably exceed those obtained for the normal fertile population. The purpose of this study was to resolve the cellular source of this enhanced activity. Semen samples from a cohort of oligozoospermic patients and a group of fertile controls were fractionated on discontinuous Percoll gradients to generate three cell populations (0, 50 and 100%) of differing density. For each fraction, both the steady-state and the phorbol-ester-induced chemiluminescent signals were significantly (P less than 0.001) greater for the oligozoospermic samples than for the fertile controls. In the fertile donors, leucocytes comprised the major source of reactive oxygen species, particularly in the low-density Percoll fractions; in oligozoospermic patients, however, spermatozoa were identified as a second major source of reactive oxygen species. Particularly striking was an intense phorbol-ester-induced chemiluminescent signal generated by oligozoospermic spermatozoa, purified by passage through isotonic Percoll and free of leucocyte contamination, which was 167 times greater than the median signal generated by the corresponding fraction from the fertile controls (P less than 0.001). These results emphasize the importance of spermatozoa as a major source of reactive oxygen species in oligozoospermia and have implications for the diagnosis and treatment of this condition, as well as for the design of appropriate diagnostic strategies.

Sperm penetration into a hyaluronic acid polymer as a means of monitoring functional competence

The diagnostic significance of sperm penetration assays based on a commercially available hyaluronate preparation (Sperm Select) has been investigated in the male partners of 77 couples characterized by a normal female partner. Sperm penetration into hyaluronate was highly correlated with the ability of the same sperm populations to penetrate bovine cervical mucus and, moreover, depended on the same attributes of semen quality, including the morphology of the spermatozoa, their number, and their motility as reflected by their mean path velocity. Stepwise multiple regression analyses employing these independent variables generated r values of 0.821 to 0.931, depending on the criterion of hyaluronate penetration used; path velocity was consistently the most informative variable according to the standardized regression coefficients. The relationship between hyaluronate penetration and sperm movement was so close that multiple regression equations could be generated that were capable of accounting for up to 76% of the variance in sperm velocity measurements obtained with a computerized image analysis system. Regression equations could also be generated using the hyaluronate penetration data that could account for 65% of the variance observed in an A23187-enhanced zona-free hamster oocyte penetration test, including the successful identification of the subpopulation of patients in whom 0% oocyte penetration had been recorded. Within the same data set, independent variables based on bovine cervical mucus penetration could only account for 43.5% of the variance in sperm-oocyte fusion. Hyaluronate penetration therefore appears to offer a simple, objective means of generating information on the functional competence of human spermatozoa that should find a role in routine diagnostic services where the more specialized tests are not available.