Candidate Electromagnetic Counterpart to the Binary Black Hole Merger Gravitational-Wave Event S190521g.

We report the first plausible optical electromagnetic counterpart to a (candidate) binary black hole merger. Detected by the Zwicky Transient Facility, the electromagnetic flare is consistent with expectations for a kicked binary black hole merger in the accretion disk of an active galactic nucleus [B. McKernan, K. E. S. Ford, I. Bartos et al., Astrophys. J. Lett. 884, L50 (2019)AJLEEY2041-821310.3847/2041-8213/ab4886] and is unlikely [

Exploring reasons for overuse of contralateral prophylactic mastectomy in Canada.

Background: Contralateral prophylactic mastectomy (cpm) in women with known unilateral breast cancer (bca) has been increasing despite the lack of supportive evidence. The purpose of the present study was to identify the determinants of cpm in women with unilateral bca. Methods: This qualitative descriptive study used semi-structured interviews informed by the Theoretical Domains Framework. We interviewed 74 key informants (surgical oncologists, plastic surgeons, medical oncologists, radiation oncologists, nurses, women with bca) across Canada. Interviews were analyzed using thematic analysis and an analysis for shared and discipline-specific beliefs. Results: In total, 58 factors influencing the use of cpm were identified: 26 factors shared by various health care professional groups, 15 discipline-specific factors (identified by a single health care professional group), and 17 factors shared by women with unilateral bca. Health care professionals identified more factors discouraging the use of cpm (n = 26) than encouraging its use (n = 15); women with bca identified more factors encouraging use of cpm (n = 12) than discouraging its use (n = 5). The factor most commonly identified by health care professionals that encouraged cpm was lack of awareness of existing evidence or guidelines for the appropriate use of cpm (n = 44, 75%). For women with bca, the factor most likely influencing their decision for cpm was wanting a better esthetic outcome (n = 14, 93%). Conclusions: Multiple factors discouraging and encouraging the use of cpm in unilateral bca were identified. Those factors identify potential individual, team, organization, and system targets for behaviour change interventions to reduce cpm.

Patient decision aid for contralateral prophylactic mastectomy for use in the consultation: a feasibility study.

Background: Rates of contralateral prophylactic mastectomy (cpm) continue to rise internationally despite evidence-based guidance strongly discouraging its use in most women with unilateral breast cancer. The purpose of the present study was to develop and assess the feasibility of a knowledge translation tool [a patient decision aid (da)] designed to enhance evidence-informed shared decision-making about cpm. Methods: A consultation da was developed using the Ottawa Patient Decision Aid Development eTraining in consultation with clinicians and knowledge translation experts. The final da was then assessed for feasibility with health care professionals and patients across Canada. The assessment involved a survey completed online (health care professionals) or by telephone (patients). Survey data were analyzed using descriptive statistics for closed-ended questions and qualitative content analysis for open-ended questions. Results: The 51 participants who completed the survey included 39 health care professionals and 12 patients. The da was acceptable; 88% of participants viewed it as having the right amount of information or slightly more or less information than they would like. Almost all participants (98%) felt that the da would prepare patients to make better decisions. The aid was perceived to be usable, with 73% of participants stating that they would be willing to use or share the da. Conclusions: The cpm patient da developed for the present study was viewed by health care professionals and patients across Canada to be acceptable and usable during the clinical consultation. It holds promise as a knowledge translation tool to be used by clinicians in consultation with women who have unilateral breast cancer to enhance evidence-informed and shared decision-making with respect to undergoing cpm.

Implications of Dedicated Seismometer Measurements on Newtonian-Noise Cancellation for Advanced LIGO.

Newtonian gravitational noise from seismic fields will become a limiting noise source at low frequency for second-generation, gravitational-wave detectors. It is planned to use seismic sensors surrounding the detectors' test masses to coherently subtract Newtonian noise using Wiener filters derived from the correlations between the sensors and detector data. In this Letter, we use data from a seismometer array deployed at the corner station of the Laser Interferometer Gravitational Wave Observatory (LIGO) Hanford detector combined with a tiltmeter for a detailed characterization of the seismic field and to predict achievable Newtonian-noise subtraction levels. As was shown previously, cancellation of the tiltmeter signal using seismometer data serves as the best available proxy of Newtonian-noise cancellation. According to our results, a relatively small number of seismometers is likely sufficient to perform the noise cancellation due to an almost ideal two-point spatial correlation of seismic surface displacement at the corner station, or alternatively, a tiltmeter deployed under each of the two test masses of the corner station at Hanford will be able to efficiently cancel Newtonian noise. Furthermore, we show that the ground tilt to differential arm-length coupling observed during LIGO's second science run is consistent with gravitational coupling.

A kilonova as the electromagnetic counterpart to a gravitational-wave source.

Gravitational waves were discovered with the detection of binary black-hole mergers and they should also be detectable from lower-mass neutron-star mergers. These are predicted to eject material rich in heavy radioactive isotopes that can power an electromagnetic signal. This signal is luminous at optical and infrared wavelengths and is called a kilonova. The gravitational-wave source GW170817 arose from a binary neutron-star merger in the nearby Universe with a relatively well confined sky position and distance estimate. Here we report observations and physical modelling of a rapidly fading electromagnetic transient in the galaxy NGC 4993, which is spatially coincident with GW170817 and with a weak, short γ-ray burst. The transient has physical parameters that broadly match the theoretical predictions of blue kilonovae from neutron-star mergers. The emitted electromagnetic radiation can be explained with an ejected mass of 0.04 ± 0.01 solar masses, with an opacity of less than 0.5 square centimetres per gram, at a velocity of 0.2 ± 0.1 times light speed. The power source is constrained to have a power-law slope of -1.2 ± 0.3, consistent with radioactive powering from r-process nuclides. (The r-process is a series of neutron capture reactions that synthesise many of the elements heavier than iron.) We identify line features in the spectra that are consistent with light r-process elements (atomic masses of 90-140). As it fades, the transient rapidly becomes red, and a higher-opacity, lanthanide-rich ejecta component may contribute to the emission. This indicates that neutron-star mergers produce gravitational waves and radioactively powered kilonovae, and are a nucleosynthetic source of the r-process elements.

Prenatal and postnatal markers of severity in congenital diaphragmatic hernia have similar prognostic ability.

OBJECTIVES: The purpose of this study was to compare prenatal versus postnatal markers of congenital diaphragmatic hernia (CDH) severity at a single fetal-care center. METHODS: A retrospective study was performed of patients having a complete prenatal evaluation and surgical repair (n = 55). Observed-to-expected lung-to-head ratio (o/eLHR), observed-to-expected total lung volume (o/eTLV), liver position (LP), a predictive dependent variable from logistic regression of o/eLHR and liver position (o/eLHR + LP), and diaphragmatic defect size per the CDH Study Group A-D classification were plotted into receiver-operating characteristics (ROC) curves. Survival and need for extracorporeal membrane oxygenation (ECMO) were primary outcomes. RESULTS: Survival was 69%, and ECMO utilization was 56%. Distribution was 80% left-sided defects. In the survival ROC curve, the area under the curve (AUC) for o/eLHR was 0.73, o/eTLV 0.74, LP 0.73, o/eLHR + LP 0.78, and defect size 0.84 (p = 0.23). The ROC curve for ECMO support showed o/eLHR had an AUC of 0.82, o/eTLV 0.89, LP 0.79, o/eLHR + LP 0.87, and defect size 0.90 (p = 0.19). The AUCs were similar when only left-sided CDH was analyzed. CONCLUSIONS: These data suggest that prenatal evaluation was equivalent to the postnatal diaphragmatic defect classification for predicting survival and need for ECMO in CDH patients.

Access to medical records for research purposes: varying perceptions across research ethics boards.

INTRODUCTION: Variation across research ethics boards (REBs) in conditions placed on access to medical records for research purposes raises concerns around negative impacts on research quality and on human subject protection, including privacy. AIM: To study variation in REB consent requirements for retrospective chart review and who may have access to the medical record for data abstraction. METHODS: Thirty 90-min face-to-face interviews were conducted with REB chairs and administrators affiliated with faculties of medicine in Canadian universities, using structured questions around a case study with open-ended responses. Interviews were recorded, transcribed and coded manually. RESULTS: Fourteen sites (47%) required individual patient consent for the study to proceed as proposed. Three (10%) indicated that their response would depend on how potentially identifying variables would be managed. Eleven sites (38%) did not require consent. Two (7%) suggested a notification and opt-out process. Most stated that consent would be required if identifiable information was being abstracted from the record. Among those not requiring consent, there was substantial variation in recognising that the abstracted information could potentially indirectly re-identify individuals. Concern over access to medical records by an outside individual was also associated with requirement for consent. Eighteen sites (60%) required full committee review. Sixteen (53%) allowed an external research assistant to abstract information from the health record. CONCLUSIONS: Large variation was found across sites in the requirement for consent for research involving access to medical records. REBs need training in best practices for protecting privacy and confidentiality in health research. A forum for REB chairs to confidentially share concerns and decisions about specific studies could also reduce variation in decisions.

Antizyme, a mediator of ubiquitin-independent proteasomal degradation and its inhibitor localize to centrosomes and modulate centriole amplification.

The potential tumor suppressor antizyme and its endogenous inhibitor (antizyme inhibitor, AZI) have been implicated in the ubiquitin-independent proteasomal degradation of proteins involved in cell proliferation as well as in the regulation of polyamine levels. We show here that both antizyme and AZI concentrate at centrosomes and that antizyme preferentially associates with the maternal centriole. Interestingly, alterations in the levels of these proteins have opposing effects on centrosomes. Depletion of antizyme in various cell lines and primary cells leads to centrosome overduplication, whereas overexpression of antizyme reduces numerical centrosome abnormalities. Conversely, silencing of the antizyme inhibitor, AZI, results in a decrease of numerical centrosome abnormalities, whereas overexpression of AZI leads to centrosome overduplication. We further show that the numerical centrosome abnormalities are due to daughter centriole amplification. In summary, our results demonstrate that alterations in the antizyme/AZI balance cause numerical centrosomal defects and suggest a role for ubiquitin-independent proteasomal degradation in centrosome duplication.

Automated eye tracking system calibration using artificial neural networks.

The electro-oculogram (EOG) continues to be widely used to record eye movements especially in clinical settings. However, an efficient and accurate means of converting these recordings into eye position is lacking. An artificial neural network (ANN) that maps two-dimensional (2D) eye movement recordings into 2D eye positions can enhance the utility of such recordings. Multi-layer perceptrons (MLPs) with non-linear activation functions and trained with back propagation proved to be capable of calibrating simulated EOG data to a mean accuracy of 0.33 degrees . Linear perceptrons (LPs) were only nearly half as accurate. For five subjects, the mean accuracy provided by the MLPs was 1.09 degrees of visual angle ( degrees ) for EOG data, and 0.98 degrees for an infrared eye tracker. MLPs enabled calibration of 2D saccadic EOG to an accuracy not significantly different from that obtained with the infrared tracker. Using initial weights trained on another person reduced MLP training time, reaching convergence in as little as 20 iterations.

Fertility after unilateral cryptorchidism. Paternity, time to conception, pretreatment testicular location and size, hormone and sperm parameters.

OBJECTIVE: To further evaluate whether fertility is decreased among a cohort of men with previous unilateral cryptorchidism as compared with a control group of men. SUBJECTS AND METHODS: Formerly unilateral cryptorchid men who had undergone orchiopexy between the years of 1955 and 1975 at the Children's Hospital of Pittsburgh and a control group of men who were matched for age of an unrelated surgery at the same institution were evaluated by review of medical records and by completion of a questionnaire. 359 previously cryptorchid men were identified as having attempted paternity. Of these men, 320 had information concerning preoperative testicular location and 163 for preoperative testicular size. 106 of these men had levels of testosterone, inhibin B, FSH, and LH measured, while 95 of the men had semen analyses. RESULTS: Among men who had attempted paternity, there was no statistical difference in success of paternity between the previously unilateral group (89.7%) and the control group (93.7%). There was no difference in the mean time to conception (7.1 +/- 0.7 months for the unilateral group vs. 6.9 +/- 2.3 for the control group). Within the unilateral group in regard to success at paternity, no difference was found compared with the age of orchiopexy, preoperative testicular location, or preoperative testicular size. Inhibin B levels were lower among the unilateral group. FSH, LH, testosterone, sperm density, motility and morphology were not different, but considerable variation was noted within the cryptorchid group. CONCLUSIONS: In this continued evaluation of a cohort of previously cryptorchid men who had undergone unilateral orchiopexy, paternity does not appear to be significantly compromised after unilateral cryptorchidism. Unilateral cryptorchidism appears to be one of several factors contributing to infertility, similar to those found in the general population. No correlation was found between success at paternity and the age of orchiopexy, preoperative testicular size or preoperative testicular location. Inhibin B levels were lower while FSH, LH, T and sperm parameters did not differ.

Operative treatment of interdigital neuroma. A long-term follow-up study.

BACKGROUND: The literature regarding the outcome of surgical treatment of interdigital neuroma is incomplete. The purpose of this study was to assess the demographics associated with the presentation of an interdigital neuroma as well as the long-term clinical results of operative resection by a single surgeon. METHODS: A retrospective review of the patient records of one orthopaedic foot and ankle surgeon identified eighty-two patients who had been treated operatively for a primary, persistently painful interdigital neuroma more than three years previously. Of these eighty-two patients, sixty-six (seventy-one feet, seventy-four neuromas) returned at an average of 5.8 years for a follow-up evaluation, which included a review of the interval history since the surgery, a physical examination, a radiographic evaluation, and an assessment of the patient's satisfaction with the result of the surgery. RESULTS: Overall satisfaction was rated as excellent or good by fifty-six (85%) of the sixty-six patients. Forty-six (65%) of the seventy-one feet were pain-free at the time of final follow-up. The patients who had had either bilateral neuroma excision or excisions of adjacent neuromas in the same foot in a staged fashion had a slightly lower level of satisfaction, but this difference was not significant. While major activity restrictions following surgery were uncommon, mild or major shoe-wear restrictions were noted by forty-six of the sixty-six patients. Although there was subjective numbness in thirty-six of the seventy-one feet, the pattern of numbness was quite variable and it was bothersome in only four feet. CONCLUSION: With careful preoperative evaluation and patient selection, resection of a symptomatic interdigital neuroma through a dorsal approach can result in a high percentage of successful results more than five years following the procedure.

The precursor pro-nerve growth factor is the predominant form of nerve growth factor in brain and is increased in Alzheimer's disease.

Nerve growth factor (NGF) is important for regulation, differentiation, and survival of peripheral and central nervous system neurons, including basal forebrain cholinergic neurons (BFCN) which degenerate in Alzheimer's disease (AD). Mature NGF protein is processed from a larger precursor, proNGF. We demonstrate that proNGF is the predominant form of NGF in mouse, rat, and human brain tissue, whereas little or no mature NGF is detected. Previous reports showed NGF protein, measured by ELISA, is increased in AD BFCN target regions such as hippocampus and cortex. Using Western blotting, we demonstrate a twofold increase in proNGF in AD parietal cortex compared to controls, indicating that it is this precursor form, proNGF, that accumulates in AD. This increase may reflect either a role for biologically active proNGF or posttranslational disturbances in NGF biosynthesis that decrease the processing of proNGF to mature NGF in AD.

No relationship of testicular size at orchiopexy with fertility in men who previously had unilateral cryptorchidism.

PURPOSE: We determined whether testicular size at orchiopexy is predictive of fertility potential and whether size correlates with sperm parameters, hormone levels or testicular volume in adulthood. MATERIALS AND METHODS: Testicular size obtained from the operative notes of patients who underwent unilateral orchiopexy was classified as normal, small or large for age. These data were compared with outcome data. Paternity data were included on 166 men who reported achieving or unsuccessfully attempting paternity for 12 or more months. Of the men 49 provided blood for hormone level measurement, 43 underwent semen analysis and in 29 testicular volume was determined. RESULTS: In the 166 men, including 98, 65 and 3 with small, normal and large testes for age at orchiopexy, respectively, there was no difference in paternity based on testicular size. Of those who achieved paternity time to conception did not differ based on size. Mean age at surgery also did not differ, nor did the percent of small versus normal testes in the age categories 0 to 2, 3 to 5, 6 to 8 and 9 to 11 years. There was no difference in men with small or normal testicular size at surgery in mean luteinizing hormone, follicle-stimulating hormone, testosterone or inhibin B. Sperm density, motility and morphology, and volume in adulthood of a previously undescended testis, previously descended testis or previously undescended and descended testes did not differ in these 2 groups, although the previously undescended testis was smaller than the contralateral testis. CONCLUSIONS: In men with a history of unilateral cryptorchidism small testicular size at orchiopexy is not associated with decreased paternity (89.8%), abnormal hormone levels, a lower sperm count or decreased testicular volume in adulthood.

Treatment of PC12 cells with nerve growth factor increases iron uptake.

Phaeochromocytoma PC12 cells treated with nerve growth factor (NGF) differentiate into a neuronal phenotype. Here we compare the uptake of transferrin-bound and non-transferrin-bound iron in NGF-treated (neuronal phenotype) and control (proliferating) PC12 cells. The non-transferrin-bound iron uptake was greater in the NGF-treated cells than in the control, independently of the uptake time, the iron-chelating agents used, the oxidation state of iron (Fe(2+) or Fe(3+)) and the iron concentration tested. The NGF-treated cells expressed L-type and N-type voltage-operated Ca(2+) channels. Nitrendipine (an L-type inhibitor) and possibly omega-conotoxin (an N-type inhibitor) inhibited the iron uptake by 20%. Thapsigargin inhibits the endoplasmic reticulum Ca(2+) pump and allowed Mn(2+) entry into cells. Preincubating PC12 cells with thapsigargin increased the iron uptake. The rate of transferrin-bound iron uptake was less than 1% of the non-transferrin-bound iron uptake and the maximum transferrin-bound iron uptake was also very low. We conclude that an increase in the iron uptake by multiple pathways accompanies the transition of PC12 cells from the proliferating to the neuronal phenotype.

Roger A. Mann Award . The reliability of angular measurements in hallux valgus deformities. .

The purpose of this study was to determine the intraobserver and inter-observer reliability of physicians on a repetitive basis in making angular measurements of hallux valgus deformities. The hallux valgus angle, the 1-2 intermetatarsal angle, and the distal metatarsal articular angle and the assessment of congruency/subluxation of the first MTP joint were evaluated on a repetitive basis. Physicians were provided with a series of black and white photographs of radiographs with a hallux valgus deformity. Three different sets of photographs randomly ordered were sent at a minimum interval of six weeks to the participants. Participating physicians were extremely reliable in the measurement of the 1-2 metatarsal angle. 96.7% of the photographs were repeatedly measured within a range of 5 degrees or less. The angular measurements to determine the hallux valgus angle were slightly less reliable, but 86.2% of photos were repeatedly measured within a range of 5 degrees or less. In the measurement of the distal metatarsal articular angle, 58.9% of photographs were repeatedly measured within a range of 5 degrees or less. There was a wide range within physician evaluators who recognized very few congruent joints (2 of 21) and those who recognized several congruent joints (11 of 21). Most physicians appeared to be internally consistent in the assessment of MTP congruency; however, some photographs were much more difficult to assess than others. This study validates the reliability of the measurement of the hallux valgus and the 1-2 metatarsal angle. The interobserver reliability in the measurement of the distal metatarsal articular angle is questioned.

Fertility after bilateral cryptorchidism. Evaluation by paternity, hormone, and semen data.

PURPOSE: Evaluation of the fertility of a cohort of formerly bilaterally cryptorchid men in comparison with a group of formerly unilaterally cryptorchid men, and a group of control men. MATERIALS AND METHODS: Using a detailed questionnaire concerning paternity and factors related to paternity, a cohort of formerly bilateral cryptorchid men were studied and compared with men who had undergone orchiopexy for unilateral cryptorchidism, and a group of control men. All study subjects had had surgery at the Children's Hospital of Pittsburgh, Pittsburgh, Pa., between 1955 and 1975. A subset of the full cohort underwent clinical evaluation that included a physical examination, serum hormonal determination and semen analyses. RESULTS: Paternity rates are significantly lower among the formerly bilaterally cryptorchid men who have attempted to father a child (65.3%) as compared to the formerly unilaterally cryptorchid (89.7%; p < 0.001) and control men (93.2%; p < 0.001). Differences in the ability to father children are also apparent when semen and hormone levels are compared between the three groups. The bilateral group has significantly lower sperm density and inhibin B levels, and higher FSH and LH levels, than the unilateral and control groups. CONCLUSIONS: Men born with bilateral cryptorchidism have severely compromised fertility in adulthood. This reduction in fertility is clearly shown in comparisons of both paternity rates, and in semen and hormone analyses, between the formerly bilateral, formerly unilateral, and control groups.

Inhibin B: comparison with indexes of fertility among formerly cryptorchid and control men.

Infertility may be a consequence of cryptorchidism. We previously reported, using a large study cohort, that 38% of formerly bilateral cryptorchid men, 10% of unilateral cryptorchid men, and 5% of the control group were infertile. Men from this cohort donated blood and semen samples for inhibin B, FSH, LH, testosterone, free testosterone, and semen analyses. Results are reported comparing the entire group; some comparisons are based on normal or low sperm density. Data are also presented for men who had fathered children or had unsuccessfully attempted paternity. Mean (+/-SD) inhibin B levels were lower for the cryptorchid men (109 +/- 59 pg/mL) than the control men (153 +/- 60; P < 0.001), and FSH levels were higher (7.4 +/- 6.2 and 4.0 +/- 3.2; P < 0.0001). Inhibin B levels correlated with all other parameters for the cryptorchid group; however, correlations for the control group were only found with gonadotropins. Among the cryptorchid men, levels were significantly greater among men with normal sperm counts than men with low sperm counts (124 +/- 47 vs. 75 +/- 48 pg/mL; P < 0.0001). No difference was present for the control group (155 +/- 61 vs. 149 +/- 63 pg/mL). When the fertile group (based on paternity) vs. the infertile group (based on attempted paternity) were compared, significant differences were found for the cryptorchid group (117 +/- 62 vs. 73 +/- 52 pg/mL; P < 0.03), but not the control group (163 +/- 62 vs. 146 +/- 73 pg/mL). These data reveal relationships not apparent among the control group of men, which includes infertile men. Inhibin B data suggest that a larger portion of formerly cryptorchid men have compromised testicular function than indicated by paternity data. Low levels of inhibin B among individuals are an indication of diminished seminiferous tubule function and thus compromised potential for fertility. Low inhibin B levels together with elevated FSH levels and decreased sperm density are indicative of a high risk of infertility.

Calcaneal fractures in the industrial patient.

A retrospective review was performed on industrial patients who sustained calcaneal fractures within the State of Idaho during the years 1992 to 1994, and these patients were insured by the Idaho State Insurance Fund. Of 48 calcaneal fractures that occurred during this period, 18 were non-displaced extra-articular fractures and 30 were displaced intra-articular fractures. An independent evaluator contacted each patient and performed chart reviews regarding the work history, period of time off work, and cost incurred with the injury. A total of 24 primary surgical procedures were performed on patients who sustained a displaced intra-articular calcaneal fracture and 31 secondary procedures were performed including wound debridement, hardware removal, skin grafting, and secondary subtalar fusion. For patients whose calcaneal fractures could be treated with non-operative care, the average time from injury until return to work was 18 weeks, and the average total cost of injury was $14,230. For patients whose calcaneal fractures required open reduction and internal fixation, the average time loss from work was 35 weeks, and the average total cost of injury was $31,004. Seven patients whose calcaneal fractures were initially treated with an open reduction, internal fixation later underwent a hindfoot arthrodesis. The average time off work for these patients was 69 weeks and the average total cost of injury was $65,384. Fractures were rated on postoperative radiographs according to the quality of their operative reduction. Fractures that were non-anatomically reduced had an increased tendency to require a subtalar fusion. Nine patients sustained other injuries associated with their calcaneal fracture and three patients sustained an open fracture. Both concurrent injuries and open fractures were associated with increased total cost and increased time off work. The total cost of injury was doubled as was time off work when an open reduction and internal fixation was followed later by a secondary subtalar arthrodesis.

Paternity and hormone levels after unilateral cryptorchidism: association with pretreatment testicular location.

PURPOSE: We determined differences in paternity and levels of the hormones inhibin B, follicle- stimulating hormone, luteinizing hormone, testosterone and free testosterone based on the preoperative location of the undescended testis in men with previous unilateral cryptorchidism. MATERIALS AND METHODS: Testicular location was determined by a review of the medical records and paternity or attempted paternity using a detailed questionnaire administered to 320 men with previous unilateral cryptorchidism. In 103 cases we performed semen analysis and measured the levels of the hormones inhibin B, luteinizing hormone, follicle-stimulating hormone, testosterone and free testosterone. Paternity, sperm count and hormonal parameters were compared with cryptorchid testicular location using analysis of variance and chi-square analysis. Logistic regression was done to analyze pretreatment testicular location as a risk factor for infertility. RESULTS: Paternity, duration of attempted conception in men who achieved paternity, sperm count and hormone levels did not differ based on pretreatment abdominal, internal ring, inguinal canal, external ring, upper scrotum or ectopic testicular location. The overall paternity rate was 90% with the lowest rate of 83.3% in the abdominal group. More than 12 months were required to achieve conception in 28.9% of the study group overall and in 39.4% of the abdominal group. Varicocele and a partner with fertility problems were risk factors for infertility, while abdominal testicular location caused borderline significant risk. CONCLUSIONS: Preoperative testicular location in men with previous unilateral cryptorchidism is not a major determinant of fertility according to paternity, sperm count or hormone levels.