Study of diffusive- and convective-transport mediated microtumor growth in a controlled microchamber.

In this paper, we report on using mass transport to control nutrition supply of colorectal cancer cells for developing a microtumor in a confined microchamber. To mimic the spatial heterogeneity of a tumor, two microfluidic configurations based on resistive circuits are designed. One has a convection-dominated microchamber to simulate the tumor region proximal to leaky blood vessels. The other has a diffusion-dominated microchamber to mimic the tumor core that lacks blood vessels and nutrient supply. Thus, the time for nutrition to fill the microchamber can vary from tens of minutes to several hours. Results show that cells cultured under a diffusive supply of nutrition have a high glycolytic rate and a nearly constant oxygen consumption rate. In contrast, cells cultured under convective supply of nutrition have a gradual increase of oxygen consumption rate with a low glycolytic rate. This suggests that cancer cells have distinct reactions under different mass transport and nutrition supply. Using these two microfluidic platforms to create different rate of nutrition supply, it is found that a continuous microtumor that almost fills the mm-size microchamber can be developed under a low-nutrient supply environment, but not for the convective condition. It also is demonstrated that microchannels can simulate the delivery of anti-cancer drugs to the microtumor under controlled mass-transport. This method provides a means to develop a larger scale microtumor in a lab-on-a-Chip system for post development and stimulations, and microchannels can be applied to control the physical and chemical environment for anti-cancer drug screening.

Association Between Positive Cultures During Admission and 1-Year Mortality in Patients With Cancer Receiving Perioperative Intensive Care.

The number of patients with cancer being admitted to intensive care units (ICUs) is increasing worldwide, and these patients are vulnerable to infection. This study aimed to address the long-term impact of positive cultures during admission on 1-year mortality among patients with cancer who received perioperative intensive care. This retrospective cohort study enrolled adult patients with cancer who were admitted to ICUs and received surgery during 2011 to 2016 at a tertiary hospital in central Taiwan. Cancer-related data were retrieved from the cancer registry, and data during ICU admissions were obtained from the electronic medical records. We compared the survival curves between patients with and without positive clinical cultures using log-rank test and used a multivariable Cox proportional hazards regression model to evaluate the influence of positive clinical cultures on 1-year mortality. A total of 638 patients were included for analyses, and 37.9% of them had positive cultures during the index admission. In-hospital mortality was 9.1%, while 1-year mortality was 21.0%. Compared with patients who survived, patients who died were significantly more likely to have positive cultures (59.7% vs 32.1%), to have a higher Acute Physiology and Chronic Health Evaluation II scores (median 21.8 vs 19.0), and to receive mechanical ventilation (86.6% vs 77.4%). Survival analysis found that positive cultures of blood, the respiratory tract, the urinary tract, or the skin and soft tissue were associated with an increased 1-year mortality. Multivariable Cox proportional hazards regression analysis found that positive cultures of blood, the respiratory tract, the urinary tract, or the skin and soft tissue (hazard ratio: 1.621; 95% confidence interval: 1.087-2.419) were significantly associated with 62.1% increased hazards of death within 1 year after the ICU admission. A positive culture during admission was associated with a worsened long-term survival among patients with cancer who received perioperative intensive care. Further studies are needed to confirm this association.

Risk of psychiatric disorders following trigeminal neuralgia: a nationwide population-based retrospective cohort study.

BACKGROUND: TN is one of the most common causes of facial pain. A higher prevalence of psychiatric co-morbidities, especially depressive disorder, has been proven in patients with TN; however, a clear temporal-causal relationship between TN and specific psychiatric disorders has not been well established. We performed a nationwide population-based retrospective cohort study to explore the relationship between TN and the subsequent development of psychiatric disorders, including schizophrenia, bipolar disorder, depressive disorder, anxiety disorder, and sleep disorder. METHODS: We identified subjects who were newly diagnosed with TN between January 1, 2000 and December 31, 2010 in the Taiwan National Health Insurance Research Database. A comparison cohort was constructed for patients without TN who were matched according to age and sex. All TN and control patients were observed until diagnosed with psychiatric disorders, death, withdrawal from the National Health Institute system, or until December 31, 2010. RESULTS: The TN cohort consisted of 3273 patients, and the comparison cohort consisted of 13,092 matched control patients without TN. The adjusted hazard ratio (aHR) of depressive disorder, anxiety disorder and sleep disorder in subjects with TN was higher than that of the controls during the follow-up [aHR: 2.85 (95% confidence interval: 2.11-3.85), aHR: 2.98 (95% confidence interval: 2.12-4.18) and aHR: 2.17 (95% confidence interval: 1.48-3.19), respectively]. CONCLUSIONS: TN might increase the risk of subsequent newly diagnosed depressive disorder, anxiety disorder, and sleep disorder, but not schizophrenia or bipolar disorder. Additional prospective studies are required to confirm these findings.

Clinical characteristics and outcome of patients with community-onset Klebsiella pneumoniae bacteremia requiring intensive care.

BACKGROUND: Klebsiella pneumoniae (K. pneumoniae) is the major pathogen of community-acquired pyogenic infections in Taiwan and can lead to poor prognosis in critically ill patients complicated with bacteremia. This study investigated the characteristics and outcome of patients with community-onset K. pneumoniae bacteremia who required intensive care. METHOD: Adult patients with community-onset K. pneumoniae bacteremia requiring intensive care were retrospectively analyzed, compared with those treated in ordinary wards, and determined for risk factors for infection-related mortality and long-term mortality at a medical center in Taiwan over a 3-year period. RESULTS: Among the 309 patients with community-onset K. pneumoniae bacteremia, 58 patients (18.8%) required intensive care. Respiratory tract infection [Odds ratio (OR) = 3.67, 95% confidence interval (CI) = 1.79-7.50, p < 0.001] was the independent risk factor for ICU admission. Infection-related mortality was 34.5%. Higher APACHE II score (OR = 1.43; 95% CI = 1.02-2.01; p = 0.041) and underlying malignant neoplasm (OR = 35.48; 95% CI = 2.54-495.57; p = 0.008) were independent predictors of infection-related mortality on multivariate logistic regression. One-year overall mortality was 58.6% and malignant neoplasm was the predisposing factor for poor long-term outcome. CONCLUSION: Nearly one fifth of patients with community-onset K. pneumoniae bacteremia required intensive care and this was associated with high mortality and poor long-term prognosis. Physicians should recognize the distinct characteristics and risk factors for mortality among these patients.

Characteristics of healthcare-associated and community-acquired Klebsiella pneumoniae bacteremia in Taiwan.

OBJECTIVES: Klebsiella pneumoniae is the major cause of community-onset pyogenic infections in Taiwan. We investigated the clinical features and outcomes of community-acquired (CA) and healthcare-associated (HCA) infections among community-onset K. pneumoniae bacteremia. METHODS: Adult patients with community-onset monomicrobial K. pneumoniae bacteremia were analysed retrospectively at a medical centre in Taiwan over a 4-year period. We compared the clinical characteristics of patients from the CA and HCA groups and identified the risk factors for infection-related mortality. RESULTS: In a total of 372 patients, HCA infections were observed in 44%. The HCA group had higher Charlson score, the Acute Physiology and Chronic Health Evaluation, version II (APACHE II) score, frequency of malignancy, rates of respiratory tract infection and bacteremia from unknown sources, and higher mortality than the CA group. Diabetes and liver abscess were predominant in the CA group. Whereas old age, APACHE II score >15, malignancy, liver cirrhosis, chronic renal failure, respiratory tract infection, skin and soft tissue infection, and inappropriate antimicrobial therapy were predictors for mortality, HCA bacteremia was not. CONCLUSIONS: HCA bacteremia showed different characteristics and higher mortality than CA bacteremia, but HCA infection was not an independent risk factor for mortality.