Gas tunnel engineering of prolyl hydroxylase reprograms hypoxia signaling in cells.

Molecular engineering of biocatalysts has revolutionized complex synthetic chemistry and sustainable catalysis. Here, we show that it is also possible to use engineered biocatalysts to reprogram signal transduction in human cells. More specifically, we manipulate cellular hypoxia (low O2) signaling by engineering the gas-delivery tunnel of prolyl hydroxylase 2 (PHD2), an iron-dependent enzymatic O2 sensor. Using computational modeling and rational protein design techniques, we resolve PHD2's gas tunnel and critical residues therein that limit the flow of O2 to PHD2's catalytic core. Systematic modification of these residues open the constriction topology of PHD2's gas tunnel with the most effectively designed mutant displaying 11-fold enhanced hydroxylation efficiency. Furthermore, transfection of plasmids that express these engineered PHD2 mutants in HEK-293T cells reveal significant reduction in the levels of hypoxia inducible factor (HIF-1α) even under hypoxic conditions. Our studies reveal that activated PHD2 mutants can reprogram downstream HIF pathways in cells to simulate physiological O2-like conditions despite extreme hypoxia and underscores the potential of engineered biocatalysts in controlling cellular function.

Serum Testosterone 60 Months after Passive-Scatter Proton Therapy for Localized Prostate Cancer.

Studies demonstrate a decline of ∼10% in serum testosterone (ST) level after X-ray radiotherapy for prostate cancer. We evaluated changes in ST for patients with low- and intermediate-risk prostate cancer receiving 70-82Gy(RBE) using passive-scatter proton therapy (PT). ST was checked at baseline (n = 358) and at 60+ months after PT (n = 166). The median baseline ST was 363.3 ng/dl (range, 82.0-974.0). The median ST 5 years after PT was 391.5 ng/dl (range, 108.0-1061.0). The difference was not statistically significant (p = 0.9341). Passive-scatter PT was not associated with testosterone suppression at 5 years, suggesting that protons may cause less out-of-field scatter radiation than X-rays.

Rectal Culture and Sensitivity Analysis for Reducing Sepsis Risk After Fiducial Marker Placement.

PURPOSE: Placement of fiducial markers for prostate radiotherapy (RT) is associated with a 2% to 3% risk of bacterial urinary tract infection (UTI) that may progress to sepsis necessitating hospitalization. These bacterial UTIs are primarily due to flouroquinolone (FQ) resistant Escherichia coli (E. coli). The incidence of this complication has increased in recent years. The purpose of this study is to determine whether rectal culture and sensitivity (C&S) to identify FQ resistant E. coli obtained before placement of fiducial markers for prostate RT reduces the likelihood of this complication. METHODS: In total, 412 patients treated with RT at the University of Florida Proton Therapy Institute between 2015 and 2017 were included in the study. Rectal C&S were obtained at the time of initial consultation which preceded placement of fiducial markers for planning and realignment for prostate RT. Patients in whom resistant E. coli were identified had their prophylactic antibiotic regimen modified accordingly. Whether bacterial UTI requiring hospitalization following fiducial placement occurred was prospectively recorded in the medical record on the first day of RT. RESULTS: One of 412 patients (0.2%) developed bacterial sepsis requiring hospitalization after fiducial placement. CONCLUSION: Rectal C&S to identify FQ resistant E. coli before placement of fiducial markers for prostate RT likely reduces the risk of bacterial UTI necessitating hospitalization.

Bacterial Urinary Tract Infection after Transrectal Placement of Fiducial Markers prior to Proton Radiotherapy for Prostate Cancer.

PURPOSE: To determine the incidence of a bacterial urinary tract infection (UTI) necessitating hospitalization after transrectal placement of fiducial markers prior to proton radiotherapy (RT) for prostate cancer. MATERIALS AND METHODS: Six hundred sixty six patients returning for follow up after proton RT consented to participate in this institutional review board (IRB) approved study. Patients were queried whether they required hospitalization within 1 month of transrectal placement of fiducial markers. Patients were treated with proton RT between August 2006 and December 2014. Median International Prostate Symptom Score (IPSS) was 7. Sixty four patients (9.6%) had diabetes, 9 patients (1.4%) had chronic obstructive pulmonary disease, 6 patients (0.9%) had prior bladder surgery, 7 patients (1.1%) had a transurethral prostatectomy within 3 months, and 549 patients (82.4%) had a course of antibiotics within 6 months. Fifty five patients (8.3%) were taking tamsulosin, 16 patients (2.4%) were taking finasteride, and 62 patients (9.3%) were taking saw palmetto. The interval between the most recent prostate biopsy prior to fiducial placement and fiducial marker placement was less than 6 months in 609 patients (91.4%). No patient had a prior recent rectal culture. RESULTS: Ten patients (1.5%) developed a bacterial UTI necessitating hospitalization after transrectal placement of fiducial markers. A bacterial UTI occurred in 3 (0.7%) of 440 patients treated from 2006 to 2012 and in 7 (3.1%) of 226 patients treated from 2013 to 2014. Univariate analysis of potential association of a bacterial UTI with the following parameters revealed: IPSS less than or greater than the median (p=0.3400), diabetes (p=0.6099), tamsulosin (p=0.9999), saw palmetto (p=0.0093), interval between prostate biopsy and placement of fiducials (p=0.9999), year of treatment (p=0.0363), and antibiotics within 6 months (p=0.2233). A bacterial UTI was observed in 4 (6.5%) of 62 patients who were taking saw palmetto versus 6 (1.0%) of 604 patients who were not taking this medication. The incidence of a bacterial UTI between 2006 and 2012 was 3 (0.7%) of 440 patients and from 2013 to 2014 was 7 (3.1%) of 226 patients. Multivariate analysis revealed that the likelihood of a bacterial UTI was increased in patients taking saw palmetto (p=0.0044) and those treated in 2013-2014 (p=0.0303). CONCLUSION: The incidence of a bacterial UTI requiring hospitalization after transrectal placement of fiducial markers prior to proton RT was 1.5% and was impacted by taking saw palmetto and year of treatment. Patients treated during 2013 and 2014 had a significantly higher risk of a bacterial UTI requiring hospitalization.

Hemorrhagic radiation cystitis.

The optimal management of persistent hemorrhagic radiation cystitis is ill-defined. Various options are available and include oral agents (ie, sodium pentosan polysulfate), intravenous drugs (ie, WF10), topical agents (ie, formalin), hyperbaric oxygen, and endoscopic procedures (ie, electrical cautery, argon plasma coagulation, laser coagulation). In general, it is best to manage patients conservatively and intervene only when necessary with the option least likely to exacerbate the cystitis. More aggressive measures should be employed only when more conservative approaches fail. Bladder biopsies should be avoided, unless findings suggest a bladder tumor, because they may precipitate a complication.

Hypofractionated passively scattered proton radiotherapy for low- and intermediate-risk prostate cancer is not associated with post-treatment testosterone suppression.

BACKGROUND: To investigate post-treatment changes in serum testosterone in low- and intermediate-risk prostate cancer patients treated with hypofractionated passively scattered proton radiotherapy. MATERIAL AND METHODS: Between April 2008 and October 2011, 228 patients with low- and intermediate-risk prostate cancer were enrolled into an institutional review board-approved prospective protocol. Patients received doses ranging from 70 Cobalt Gray Equivalent (CGE) to 72.5 CGE at 2.5 CGE per fraction using passively scattered protons. Three patients were excluded for receiving androgen deprivation therapy (n = 2) or testosterone supplementation (n = 1) before radiation. Of the remaining 226 patients, pretreatment serum testosterone levels were available for 217. Of these patients, post-treatment serum testosterone levels were available for 207 in the final week of treatment, 165 at the six-month follow-up, and 116 at the 12-month follow-up. The post-treatment testosterone levels were compared with the pretreatment levels using Wilcoxon's signed-rank test for matched pairs. RESULTS: The median pretreatment serum testosterone level was 367.7 ng/dl (12.8 nmol/l). The median changes in post-treatment testosterone value were as follows: +3.0 ng/dl (+0.1 nmol/l) at treatment completion; +6.0 ng/dl (+0.2 nmol/l) at six months after treatment; and +5.0 ng/dl (0.2 nmol/l) at 12 months after treatment. None of these changes were statistically significant. CONCLUSION: Patients with low- and intermediate-risk prostate cancer treated with hypofractionated passively scattered proton radiotherapy do not experience testosterone suppression. Our findings are consistent with physical measurements demonstrating that proton radiotherapy is associated with less scatter radiation exposure to tissues beyond the beam paths compared with intensity-modulated photon radiotherapy.

Contribution of flexor pollicis longus to pinch strength: an in vivo study.

PURPOSE: To estimate the contribution of the flexor pollicis longus (FPL) to key pinch strength. Secondary outcomes include tip pinch, 3-point chuck pinch, and grip strength. METHODS: Eleven healthy volunteers consented to participate in the study. We recorded baseline measures for key, 3-point chuck, and tip pinch and for grip strength. In order to control for instability of the interphalangeal (IP) joint after FPL paralysis, pinch measurements were repeated after immobilizing the thumb IP joint. Measures were repeated after subjects underwent electromyography-guided lidocaine blockade of the FPL muscle. Nerve conduction studies and clinical examinations were used to confirm FPL blockade and to rule out median nerve blockade. Paired t-tests were used to compare pre- and postblock means for both unsplinted and splinted measures. The difference in means was used to estimate the contribution of FPL to pinch strength. RESULTS: All 3 types of pinch strength showed a significant decrease between pre- and postblock measurements. The relative contribution of FPL for each pinch type was 56%, 44%, and 43% for key, chuck, and tip pinch, respectively. Mean grip strength did not decrease significantly. Splinting of the IP joint had no significant effect on pinch measurements. CONCLUSIONS: FPL paralysis resulted in a statistically significant decrease in pinch strength. IP joint immobilization to simulate IP joint fusion did not affect results. CLINICAL RELEVANCE: Reconstruction after acute or chronic loss of FPL function should be considered when restoration of pinch strength is important.

Proton radiotherapy for prostate cancer is not associated with post-treatment testosterone suppression.

PURPOSE: Three independent studies of photon (x-ray) radiotherapy (RT) for prostate cancer have demonstrated evidence of testosterone suppression after treatment. The present study was undertaken to determine whether this would also be the case with conformal protons. METHODS AND MATERIALS: Between August 2006 and October 2007, 171 patients with low- and intermediate-risk prostate cancer were enrolled and underwent treatment according to the University of Florida Proton Therapy Institute institutional review board-approved PR01 and PR02 protocols. Of the 171 patients, 18 were excluded because they had received androgen deprivation therapy either before (n = 17) or after (n = 1) RT. The pretreatment serum testosterone level was available for 150 of the remaining 153 patients. These 150 patients were included in the present study. The post-treatment levels were compared with the pretreatment levels. RESULTS: The median baseline pretreatment serum testosterone level was 357.9 ng/dL. The median post-treatment testosterone value was 375.5 ng/dL at treatment completion (p = .1935) and 369.9 ng/dL (p = .1336), 348.7 ng/dL (p = .7317), 353.4 ng/dL (p = .6996), and 340.9 ng/dL (p = .1669) at 6, 12, 18, and 24 months after proton therapy, respectively. CONCLUSIONS: Conformal proton therapy to the prostate, as delivered using the University of Florida Proton Therapy Institute PR01 and PR02 protocols, did not appear to significantly affect the serum testosterone levels within 24 months after RT.

Combined urinary and fecal diversion using a no bowel anastomosis technique.

PURPOSE: We present the experience at our institution with combined fecal and urinary diversion using 3 variations of a no anastomosis technique that avoids bowel anastomosis. MATERIALS AND METHODS: The charts of 10 female and 2 male patients who underwent the no bowel anastomosis technique were identified and reviewed. Information on the etiology of urination and defecation abnormalities, surgical resolution, complications, hospital stay and other pertinent aspects of management were retrospectively reviewed. RESULTS: Mean patient age was 64 years (range 36 to 83). Of the 12 patients 7 had a history of cancer treated with external beam radiotherapy, while 4 had neurological disorders with combined fecal and urinary incontinence or a history of colostomy. Mean hospital stay was 14.6 days (range 6 to 31) and mean followup was 26.6 months (range 14 to 52). There were no postoperative deaths, although a nonQ wave myocardial infarction occurred in 1 patient. CONCLUSIONS: The no anastomosis technique of combined diversion is recommended in patients with preexisting or planned diversion of the fecal stream. Avoidance of bowel anastomosis makes this technique especially advantageous in those with a history of radiotherapy.