Skin tribology: Science friction?

The application of tribological knowledge is not just restricted to optimizing mechanical and chemical engineering problems. In fact, effective solutions to friction and wear related questions can be found in our everyday life. An important part is related to skin tribology, as the human skin is frequently one of the interacting surfaces in relative motion. People seem to solve these problems related to skin friction based upon a trial-and-error strategy and based upon on our sense for touch. The question of course rises whether or not a trained tribologist would make different choices based upon a science based strategy? In other words: Is skin friction part of the larger knowledge base that has been generated during the last decades by tribology research groups and which could be referred to as Science Friction? This paper discusses the specific nature of tribological systems that include the human skin and argues that the living nature of skin limits the use of conventional methods. Skin tribology requires in vivo, subject and anatomical location specific test methods. Current predictive friction models can only partially be applied to predict in vivo skin friction. The reason for this is found in limited understanding of the contact mechanics at the asperity level of product-skin interactions. A recently developed model gives the building blocks for enhanced understanding of friction at the micro scale. Only largely simplified power law based equations are currently available as general engineering tools. Finally, the need for friction control is illustrated by elaborating on the role of skin friction on discomfort and comfort. Surface texturing and polymer brush coatings are promising directions as they provide way and means to tailor friction in sliding contacts without the need of major changes to the produc

Robot-assisted nephroureterectomy for upper tract urothelial carcinoma—feasibility and complications : a single center experience

Background: Robot-assisted nephroureterectomy (RANU) is the primary treatment for upper tract urothelial carcinoma (UTUC) at our hospital for patients with clinical stage less than T2, and for patients with invasive tumours, but unfit for major surgery. Objective: To assess peri-operative conditions and outcomes of RANU at our unit, and to evaluate the safety of the procedure. Methods: The medical records of all 166 patients undergoing RANU for suspected UTUC and followed for more than three months in a large university hospital in Sweden were reviewed retrospectively. After the exclusion of twenty patients because of previous cystectomy, simultaneous surgical procedure, or other tumour types than UTUC in the pathological report, 146 patients remained for the analyses. The primary endpoint was complication rate according to Clavien-Dindo at 90 days. Secondary endpoints were perioperative bleeding, violation of oncological surgical principles, hospital stay, and re-admission within 90 days. Results: The median age was 75 [(Inter Quartile Range) IQR 70–80] years and 57% of the patients had an ASA score above 2. According to Clavien-Dindo, one patient had a grade 3 complication, and no patient had a grade 4–5 complication. The median blood loss was 50 (IQR 20–100) ml and the median hospital stay was 6 (IQR 5–7) days. Twelve patients were re-admitted to the hospital within 90 days (eight with urinary tract infection/haematuria, one with hematoma, and three with other diseases). Conclusion: Robot-assisted nephroureterectomy is a safe procedure for patients with upper tract urothelial carcinoma, with a low risk of major surgical complications

Symptoms of sexual dysfunction among men from infertile couples : prevalence and association with testosterone deficiency

Background: This case control study aimed to investigate whether symptoms of sexual dysfunction are more common in males from infertile couples than in the general population and to explore whether symptoms of sexual dysfunction are associated to hypogonadism. Objectives: Participants were 165 subfertile men in infertile heterosexual relationships, 18–50 years of age, with sperm concentrations < 15 × 106/mL. The controls were 199 men from a population-based group, matched for age. Material and methods: Logistic regression was applied in order to calculate odds ratios (ORs) for seven different symptoms of sexual dysfunction. In a multivariate model, we tested independent effects of infertility and primary as well as secondary hypogonadism. Results: Statistically significant association between subfertility and symptoms of sexual dysfunction was found for lack of ability to control ejaculation (OR 2.2, 95% CI: 1.2–4.2). For hypogonadism, statistical significance was seen both in relation to low sexual interest/desire for sex (OR 2.3, 95% CI: 1.0–5.5) and for being worried about the size or shape of the penis (OR 3.6, 95% CI: 1.3–9.5). These associations remained statistically significant in males with primary but not those with secondary hypogonadism. Discussion: Our study showed that men from infertile couples have an increased risk of symptoms of sexual dysfunction and this risk is linked to androgen deficiency. Conclusion: Assessment of reproductive hormone levels and sexual function should routinely be done in this group of males

Risk of low bone mineral density in testicular germ cell cancer survivors : Association with hypogonadism and treatment modality

The cure rate of testicular cancer exceeds 95%, but testicular cancer survivors (TCS) are at increased risk of hypogonadism (HG). It has been suggested that TCS have reduced bone mineral density (BMD), but it is unclear whether this is related to HG or a direct effect of cancer therapy. The aim of this study was to evaluate whether TCS have decreased BMD, and if BMD is related to HG and/or the cancer treatment given. We investigated 91 TCS (mean age at diagnosis: 31 years; mean 9.3 years follow-up) and equal number of age matched controls (mean age at inclusion 40.3 years and 41.2 years, respectively). Total testosterone and LH were measured. BMD was determined using dual-energy X-ray absorptiometry (DXA). Low BMD (LBD) was defined as Z-score <-1. Compared to eugonadal TCS, both TCS with untreated HG (mean difference: -0.063 g/cm2; 95% CI: -0.122; -0.004 p = 0.037) and TCS receiving androgen replacement (mean difference -0.085 g/cm2; 95% CI: -0.168; -0.003; p = 0.043) presented with statistically significantly 6-8% lower hip BMD. At the spine, L1-L4, an 8% difference reached the level of statistical significance only for those with untreated HG (mean difference: -0.097 g/cm2; 95% CI: -0.179; -0.014; p = 0.022). TCS with untreated HG had significantly increased OR for spine L1-L4 LBD (OR = 4.1; 95% CI: 1.3; 13; p = 0.020). The associations between the treatment given and BMD were statistically non-significant, both with and without adjustment for HG. In conclusion, TCS with HG are at increased risk of impaired bone health. Prevention of osteoporosis should be considered as an important part in future follow up of these men

Low bone mineral density is associated with hypogonadism and cranial irradiation in male childhood cancer survivors

Summary: We investigated if bone mineral density was related to testosterone deficiency and/or previous cancer treatment in men who were childhood cancer survivors. Men with untreated testosterone deficiency or previous treatment with cranial irradiation were at increased risk of impaired bone health. Prevention of osteoporosis should be considered in their follow-up. Introduction: Childhood cancer survivors (CCS) are at increased risk of hypogonadism. Reduced bone mineral density (BMD) has been reported in CCS but it is unclear whether this is due to hypogonadism or a direct effect of cancer therapy. This study investigated BMD in CCS, and association with hypogonadism, previous treatment and cancer type. Methods: Investigation of 125 CCS (median age 33.7 at inclusion; 9.6 at diagnosis) and 125 age-matched population controls. Serum testosterone and luteinizing hormone were assayed and BMD at total hip and lumbar spine L1–L4 measured. The mean difference in BMD (g/cm2; 95% CI) between CCS and controls was analysed. Odds ratios (OR; 95% CI) for low BMD were also calculated. Results: Overall, BMD in the CCS cohort did not significantly differ from controls. However, compared with eugonadal CCS, the CCS with untreated hypogonadism had lower BMD at the hip (mean difference − 0.139 (− 0.210; − 0.067); p < 0.001) and spine (− 0.102 (− 0.174; − 0.030); p = 0.006). They also had a higher risk of low hip BMD (OR 4.1 (1.3; 14); p = 0.018). CCS treated with cranial irradiation also had lower BMD (hip − 0.076 (− 0.133; − 0.019); p = 0.009; spine − 0.071 (− 0.124; − 0.018); p = 0.009) compared with controls. The latter associations remained statistically significant after adjustment for hypogonadism. Conclusions: CCS with hypogonadism or previously treated with cranial irradiation are at increased risk of impaired bone health. Prevention of osteoporosis should be considered as an important part in future follow-up of these men

More Prevalent Prescription of Medicine for Hypertension and Metabolic Syndrome in Males from Couples Undergoing Intracytoplasmic Sperm Injection

Register-based studies have indicated that men with impaired fertility are at higher risk for developing various adult-onset diseases than fertile men. The majority of men undergoing ICSI treatment are sub-fertile and since they are in contact with the health care system, these men are well suited as target for preventive measures. Our study included all men (N = 459 766) who had fathered children in Sweden between 2006 and 2016. Swedish registry data was used for obtaining information regarding conception method and defining three groups of fathers – ICSI -treated, IVF – treated and non IVF/ICSI. By sourcing data from the Swedish Prescribed Drug Register, we specifically searched for information regarding prescription and usage of at least one prescription for diabetes mellitus, hypertension (HT) or dyslipidemia to serve as a proxy for metabolic disease among the study groups. If all three types of medicine were prescribed, the patient was considered as having metabolic syndrome. Our results indicate male partners in couples who became parents using ICSI to be at higher risk for being treated for hypertension (HR = 1.15 95% CI: 1.06–1.24, p = 0.001) and metabolic syndrome (HR = 1.28 95% CI: 1.01–1.58, p = 0.042) when compared to non IVF/ICSI men