Dual catheter and double-lumen cerebrospinal fluid shunt systems with backflow mechanisms.

PURPOSE: We previously developed a novel functional benchtop apparatus to simulate catheter occlusion in vitro utilizing avian vitelline membrane and chalaza to test catheter designs and de-obstruction techniques. Here, we study the integration of double-lumen catheter-mediated backflow in the shunt system assembly and its potential for an in-line de-obstruction of an obstructed ventricular catheter. METHODS: A double-lumen catheter was connected to a standard proximal shunt catheter for all trials. One limb of the double-lumen catheter was connected to the backflow mechanisms and allowed to loop back for fluid access. A micropump and a bi-corporal electromagnetic pump were utilized to provide various degrees of backflow at predetermined intervals. Flow rates were measured after initial occlusion and after implementation of the backflow mechanisms, and degrees of catheter blockage was calculated as a percentage of the unoccluded flow rate. Flow visualization was also used. RESULTS: In baseline blockage of less than 50%, the average occluding agent weighed 0.3-0.6 g with baseline flow rates of 8.5-11.9 mL/min. After 5 min of backflow using a micropump, the degree of blockage was reduced in 50% of trials. Additional backflow for 5 min did not provide further improvements in flow rate. In baseline blockage of greater than 50%, the average occluding agent weighed 0.8-1.3 g with baseline flow rates of 1.1-4.2 mL/min. After 5 min of backflow, the system demonstrated a decreased blockage in 20% of trials; additional backflow for 5 min further improved the flow rate in 40% of the total trials. Only magnetic plates provided enough force to provide pulsatile backflow in the bi-corporal electromagnetic system. CONCLUSIONS: The preliminary results of connecting a standard proximal catheter in series with a double-lumen catheter show a slight change in the percent occlusion from the baseline status several times when the retrograde flow occurred via one limb of the catheter. Additionally, the de-obstruction seems related to the length of the interval of the backflow and the initial percentage occlusion of the proximal catheter. The statistical analysis does not reveal a statistically significant reduction in occlusion in the proximal catheter with either backflow interval.

Proximal ventricular shunt catheter occlusion model.

PURPOSE: Proximal ventricular shunt catheter occlusion remains a problematic cause of shunt malfunction, and there is no consistent in vivo or in vitro model to help clinicians and researchers study this phenomenon. METHODS: An in vitro model utilizing standard proximal ventricular catheter and biological occluding agents mimicking choroid plexus was designed, constructed, and calibrated to occlude consistently within a specified timeframe. Hydrostatic pressure differential of 100 cmH2O was used as a driving force to generate flow through the catheter. Chalaza and vitelline membranes were harvested from avian eggs and used as occluding agents. Successful occlusion was defined as a greater than 90% reduction in volumetric flow rate through distal outlet. Histological sections of occluded catheters were performed and interpreted by a neuropathologist. RESULTS: Initial trials demonstrated successful standard catheter occlusion within 24 h using chalaza, vitelline membrane, and combination treatments. Repeat trials demonstrated consistency in successful occlusion within 5 min utilizing only vitelline membrane treatment. Histopathology demonstrated the vitelline membrane to consist of a thin, superficial layer of extraembryonic ectoderm; the chalaza was observed to consist of strands of mucin protein. CONCLUSIONS: An in vitro model of proximal ventricular shunt catheter occlusion was developed and calibrated for successful occlusion within 5 min. Future studies may utilize this model to rapidly test occlusion-resistant shunt designs and de-obstruction techniques.

Longitudinal Analysis of Bladder Cancer-Specific Mortality Trends in the United States.

BACKGROUND: Bladder cancer is the tenth leading cause of cancer death in the United States (US). Advances in diagnosis, imaging, and treatments have led to improvements in bladder cancer management. OBJECTIVE: To evaluate longitudinal bladder cancer mortality trends from 1999-2020 in the US by gender, race, ethnicity, age, geographic region, and urbanization category. METHODS: Age-adjusted bladder cancer death and incidence rates of individuals in the US of all ages between 1999-2020 were obtained using the CDC WONDER and NAACCR databases. Trends and average annual percent changes (AAPC) in age-adjusted Bladder Cancer-Specific Mortality (BCSM) and incidence rates were estimated. Data were analyzed from May 2023 to October 2023. RESULTS: From 1999-2020, overall BCSM decreased by 0.4% annually, with a dramatic decrease in deaths between 2015-2020 (AAPC: -2.0% [95% CI: -2.6,-1.3]). However, BCSM rates and metastatic malignant bladder cancer incidence rates from 1999-2020 increased for individuals≥85 years old (AAPC for BCSM: 0.8% [95% CI:0.5,1.1]; AAPC for metastatic malignant incidence: 2.5% [95% CI: 2.0,2.9]). Increases in BCSM were found for certain years in the South, in rural areas, and for Non-Hispanic White and Asian or Pacific Islander individuals. CONCLUSIONS: Overall mortality from bladder cancer has been decreasing in the US over two decades. Upon disaggregation, increasing trends were found for BCSM and for metastatic malignant bladder cancer incidence for individuals≥85 years old from 1999-2020. Further evaluation of these trends is essential to understand how to target specific populations to improve patient outcomes.

High-resistance proximal "scaled" ventricular catheters.

PURPOSE: Prove the concept of high-resistance proximal catheters for valve-independent treatment of hydrocephalus. METHODS: A preliminary design process yielded optimal high-resistance proximal ventricular catheters with a "scaled" design and parallel-oriented, U-shaped inlets. Prototypes were manually constructed using carving tools to stamp through silicone tubings. A testing apparatus was developed to simulate cerebrospinal fluid flow through a catheter, and the prototypes were tested against a control catheter for exhibition of an "on/off" phenomenon whereby no flow occurs at low pressures, and flow begins beyond a pressure threshold. Flow distribution was visualized with India ink. Regression analysis was performed to determine linearity. RESULTS: The new designs showed varying amounts of improved flow control with the "scaled" design showing the most practical flow rate control across various pressures, compared to the standard catheter; however, no true "on/off" phenomenon was observed. The "scaled" design showed various degrees of dynamism; its flow rate can be time dependent, and certain maneuvers such as flushing and bending increased flow rate temporarily. Variation in the number of inlets within each "scaled" prototype also affected flow rate. Contrastingly, the flow rate of standard catheters was found to be independent of the number of inlet holes. Ink flow showed even flow distribution in "scaled" prototypes. CONCLUSIONS: This initial feasibility study showed that high-resistance ventricular catheters can be designed to mimic the current/valved system. The "scaled" design demonstrated the best flow control, and its unique features were characterized.

5-HT6 receptor agonist EMD386088 impairs behavioral flexibility and working memory.

Serotonin 6 (5-HT6) receptors are primarily expressed in the central nervous system and to an even further extent brain regions responsible for learning and memory. Recent studies have demonstrated 5-HT6 receptor involvement in pathophysiological processes highlighting their therapeutic possibilities. Most research concerning the effects of 5-HT6 receptor modulation has focused on blockade despite paradoxical findings that 5-HT6 agonists and antagonists can both have pro-cognitive effects. The current experiments examine the effects of the 5-HT6 receptor agonist EMD386088 on behavioral flexibility and working memory. C57BL/6J mice received systemic injections of either 0, 2, or 4 mg/kg EMD386088 before being tested on probabilistic reversal learning, spontaneous alternation, and locomotor activity. In the probabilistic reversal learning task, the high dose of 4 mg/kg significantly impaired performance requiring more trials to reach criterion. The same dose significantly increased perseverative type errors, suggesting that the probabilistic reversal learning impairment was due to an inability to inhibit the previously learned choice pattern, rather than maintaining the new optimal choice pattern. Acute EMD386088 administration at 2 mg/kg significantly impaired spontaneous alternation performance, while the high dose of 4 mg/kg did not reach significance. These learning impairments were not due to an overall locomotor impairment as evidenced by comparable locomotor activity scores. Acute systemic 5-HT6 receptor activation with EMD386088 led to impaired behavior flexibility and working memory performance. Current findings support previous research suggesting that novel therapeutics directed at down regulation of 5-HT6 receptors may be effective in attenuating working memory and behavioral flexibility impairments commonly found in neuropsychiatric disorders such as Alzheimer's and schizophrenia.

Preoperative urine culture is unnecessary in asymptomatic men prior to prostate needle biopsy.

PURPOSE: To determine the clinical utility of preoperative urine cultures in asymptomatic men undergoing prostate needle biopsy (PNB). METHODS: One hundred fifty asymptomatic men had urine cultures obtained 14-days prior to PNB. As per study protocol, positive cultures were not treated. Antibiotic prophylaxis prior to PNB included ciprofloxacin 500 mg the night before and morning of the biopsy. Repeat urine cultures were obtained immediately prior to PNB with colony-forming units (CFUs) annotated. Infectious complications post-biopsy were recorded. RESULTS: Of the 150 men, six patients (4%) had evidence of asymptomatic bacteriuria with > 10,000 CFU/mL on office urine culture. Repeat urine cultures on morning of biopsy in all 150 patients noted a mean bacterial count of 55 CFU/mL (range 0-1000). All six patients with positive office urine cultures had < 100 CFU/mL at time of PNB. Following biopsy, four patients (2.7%) developed an infectious complication including two with sepsis and two with culture-positive UTIs. The causative organism in all cases was quinolone-resistant E. coli. None of the six patients with preoperative positive urine cultures developed an infectious complication following PNB. CONCLUSIONS: In this prospective observational study, under 5% of asymptomatic men had positive office cultures prior to PNB. Furthermore, repeat urine culture on the morning of biopsy showed resolution in these patients, and none developed post-biopsy infectious complications. Routine office urine culture in the asymptomatic male prior to PNB was unnecessary.

Kidney function outcomes following thermal ablation of small renal masses.

The diagnosis of small renal masses (SRMs) continues to increase likely attributable to widespread use of axial cross-sectional imaging. Many of these SRMs present in elderly patients with abnormal baseline renal function. Such patients are at risk for further decline following therapeutic intervention. Renal thermal ablation presents one approach for management of SRMs whereby tumors are treated in situ without need for global renal ischemia. These treatment characteristics contribute to favorable renal function outcomes following kidney tumor ablation particularly in patients with an anatomic or functional solitary renal unit.

Predictors of motivation to change in mandated college students following a referral incident.

The purpose of present study was to understand factors that are related to a desire or motivation to change (MTC) alcohol use in a sample of college students mandated to receive an alcohol intervention. We examined characteristics of and reactions to the referral event, typical alcohol use involvement, and alcohol beliefs about the perceived importance of drinking in college assessed by the College Life Alcohol Salience Scale (CLASS; Osberg et al., 2010) as predictors of MTC following referral to an alcohol intervention. College students (N = 932) who presented for a mandatory alcohol intervention following a referral event (e.g., citation for underage drinking, medical attention for an alcohol-related incident, or driving under the influence) completed an assessment prior to receiving an alcohol intervention. Higher perceived aversiveness of the referral event and higher personal responsibility one felt for the occurrence of the event were positively related to higher MTC. Although alcohol beliefs about the role of drinking in college were not significantly related to either event aversiveness or responsibility, it was negatively related to MTC even after controlling for alcohol use involvement variables. Alcohol beliefs about the role of drinking in college represent an important construct that is related to increased alcohol use and alcohol-related problems and decreased MTC in a sample of college students. Interventions aimed at reducing alcohol beliefs about the role of drinking in college may be an effective strategy to reduce alcohol use and alcohol-related problems by college students.