Unveiling the future of COVID-19 patient care: groundbreaking prediction models for severe outcomes or mortality in hospitalized cases

Background

Previous studies have identified COVID-19 risk factors, such as age and chronic health conditions, linked to severe outcomes and mortality. However, accurately predicting severe illness in COVID-19 patients remains challenging, lacking precise methods.

Objective

This study aimed to leverage clinical real-world data and multiple machine-learning algorithms to formulate innovative predictive models for assessing the risk of severe outcomes or mortality in hospitalized patients with COVID-19.

Methods

Data were obtained from the Taipei Medical University Clinical Research Database (TMUCRD) including electronic health records from three Taiwanese hospitals in Taiwan. This study included patients admitted to the hospitals who received an initial diagnosis of COVID-19 between January 1, 2021, and May 31, 2022. The primary outcome was defined as the composite of severe infection, including ventilator use, intubation, ICU admission, and mortality. Secondary outcomes consisted of individual indicators. The dataset encompassed demographic data, health status, COVID-19 specifics, comorbidities, medications, and laboratory results. Two modes (full mode and simplified mode) are used; the former includes all features, and the latter only includes the 30 most important features selected based on the algorithm used by the best model in full mode. Seven machine learning was employed algorithms the performance of the models was evaluated using metrics such as the area under the receiver operating characteristic curve (AUROC), accuracy, sensitivity, and specificity.

Results

The study encompassed 22,192 eligible in-patients diagnosed with COVID-19. In the full mode, the model using the light gradient boosting machine algorithm achieved the highest AUROC value (0.939), with an accuracy of 85.5%, a sensitivity of 0.897, and a specificity of 0.853. Age, vaccination status, neutrophil count, sodium levels, and platelet count were significant features. In the simplified mode, the extreme gradient boosting algorithm yielded an AUROC of 0.935, an accuracy of 89.9%, a sensitivity of 0.843, and a specificity of 0.902.

Conclusion

This study illustrates the feasibility of constructing precise predictive models for severe outcomes or mortality in COVID-19 patients by leveraging significant predictors and advanced machine learning. These findings can aid healthcare practitioners in proactively predicting and monitoring severe outcomes or mortality among hospitalized COVID-19 patients, improving treatment and resource allocation.

Core and penumbra estimation using deep learning-based AIF in association with clinical measures in computed tomography perfusion (CTP)

OBJECTIVES

To investigate whether utilizing a convolutional neural network (CNN)-based arterial input function (AIF) improves the volumetric estimation of core and penumbra in association with clinical measures in stroke patients.

METHODS

The study included 160 acute ischemic stroke patients (male = 87, female = 73, median age = 73 years) with approval from the institutional review board. The patients had undergone CTP imaging, NIHSS and ASPECTS grading. convolutional neural network (CNN) model was trained to fit a raw AIF curve to a gamma variate function. CNN AIF was utilized to estimate the core and penumbra volumes which were further validated with clinical scores.

RESULTS

Penumbra estimated by CNN AIF correlated positively with the NIHSS score (r = 0.69; p < 0.001) and negatively with the ASPECTS (r =  - 0.43; p < 0.001). The CNN AIF estimated penumbra and core volume matching the patient symptoms, typically in patients with higher NIHSS (> 20) and lower ASPECT score (< 5). In group analysis, the median CBF < 20%, CBF < 30%, rCBF < 38%, Tmax > 10 s, Tmax > 10 s volumes were statistically significantly higher (p < .05).

CONCLUSIONS

With inclusion of the CNN AIF in perfusion imaging pipeline, penumbra and core estimations are more reliable as they correlate with scores representing neurological deficits in stroke.

CRITICAL RELEVANCE STATEMENT

With CNN AIF perfusion imaging pipeline, penumbra and core estimations are more reliable as they correlate with scores representing neurological deficits in stroke.

Determinants of coronavirus disease 2019 infection by artificial intelligence technology: A study of 28 countries

Objectives

The coronavirus disease 2019 pandemic has affected countries around the world since 2020, and an increasing number of people are being infected. The purpose of this research was to use big data and artificial intelligence technology to find key factors associated with the coronavirus disease 2019 infection. The results can be used as a reference for disease prevention in practice.

Methods

This study obtained data from the "Imperial College London YouGov Covid-19 Behaviour Tracker Open Data Hub", covering a total of 291,780 questionnaire results from 28 countries (April 1~August 31, 2020). Data included basic characteristics, lifestyle habits, disease history, and symptoms of each subject. Four types of machine learning classification models were used, including logistic regression, random forest, support vector machine, and artificial neural network, to build prediction modules. The performance of each module is presented as the area under the receiver operating characteristics curve. Then, this study further processed important factors selected by each module to obtain an overall ranking of determinants.

Results

This study found that the area under the receiver operating characteristics curve of the prediction modules established by the four machine learning methods were all >0.95, and the RF had the highest performance (area under the receiver operating characteristics curve is 0.988). Top ten factors associated with the coronavirus disease 2019 infection were identified in order of importance: whether the family had been tested, having no symptoms, loss of smell, loss of taste, a history of epilepsy, acquired immune deficiency syndrome, cystic fibrosis, sleeping alone, country, and the number of times leaving home in a day.

Conclusions

This study used big data from 28 countries and artificial intelligence methods to determine the predictors of the coronavirus disease 2019 infection. The findings provide important insights for the coronavirus disease 2019 infection prevention strategies.

Atypical Teratoid/Rhabdoid Tumor in Taiwan: A Nationwide, Population-Based Study

Simple Summary

Atypical teratoid/rhabdoid tumor (AT/RT) is a rare, highly malignant CNS neoplasm with poor prognosis. A retrospective population-based analysis of patients with the diagnosis of AT/RT, registered between 1999 and 2014 in Taiwan, showed that: (1) AT/RT had a higher prevalence in males, in children < 36 months of age, and at infratentorial sites; (2) older age (≥12 months), presence of the tumor in the supratentorial region, use of radiotherapy, chemotherapy, or both were associated with better prognosis compared to surgery or no treatment. These data represent a historical experience with AT/RT in Taiwan and may inform risk stratification and clinical trial design.

Abstract

Background: Atypical teratoid/rhabdoid tumor (AT/RT) is a rare, highly aggressive embryonal brain tumor most commonly presenting in young children. Methods: We performed a nationwide, population-based study of AT/RT (ICD-O-3 code: 9508/3) in Taiwan using the Taiwan Cancer Registry Database and the National Death Certificate Database. Results: A total of 47 cases (male/female = 29:18; median age at diagnosis, 23.3 months (IQR: 12.5–87.9)) were diagnosed with AT/RT between 1999 and 2014. AT/RT had higher prevalence in males (61.70%), in children < 36 months (55.32%), and at infratentorial or spinal locations (46.81%). Survival analyses demonstrated that patients ≥ 3 years of age (n = 21 (45%)) had a 5y-OS of 41% (p < 0.0001), treatment with radiotherapy only (n = 5 (11%)) led to a 5y-OS of 60%, treatment with chemotherapy with or without radiotherapy (n = 27 (62%)) was associated with a 5y-OS of 45% (p < 0.0001), and patients with a supratentorial tumor (n = 11 (23%)) had a 5y-OS of 51.95%. Predictors of better survival on univariate Cox proportional hazard modeling and confirmed with multivariate analysis included older age (≥1 year), supratentorial sites, and the administration of radiotherapy, chemotherapy, or both. Gender had no effect on survival. Conclusion: Older age, supratentorial site, and treatment with radiotherapy, chemotherapy, or both significantly improves the survival of patients with AT/RT.

Comparison of Acute and Chronic Surgical Complications Following Robot-Assisted, Laparoscopic, and Traditional Open Radical Prostatectomy Among Men in Taiwan

IMPORTANCE

Few studies have evaluated long-term surgical complications in patients with prostate cancer (PC) who receive open radical prostatectomy (ORP), laparoscopic radical prostatectomy (LRP), or robot-assisted radical prostatectomy (RARP).

OBJECTIVE

To examine the perioperative and postoperative surgical complications among patients with PC who underwent ORP, LRP, or RARP.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study included patients who received a diagnosis of resectable PC and underwent RP between January 1 and December 31, 2015. Participants were enrolled in the Taiwan Cancer Registry. The index date was the date of surgery, and the follow-up duration was the period from the index date to December 31, 2018. Data analysis was performed in September 2020.

EXPOSURES

ORP, LRP, or RARP.

MAIN OUTCOMES AND MEASURES

Two multivariate mixed models accounting for hospital clusters were fitted to ascertain the association of RARP with treatment outcomes (ie, hospital stay, blood transfusion, postoperative pain, erectile dysfunction, urinary incontinence, and hernia); general linear regression models were used for continuous outcomes, the amount of blood transfused, and hospital stay, and logistic regression models were used for analyzing postoperative outcomes and surgical complications.

RESULTS

Of the 1407 patients included in this study, 315 (22.4%) received ORP (mean [SD] age, 66.4 [6.8] years), 276 (19.6%) received LRP (mean [SD] age, 66.8 [6.4] years), and 816 (58.0%) received RARP (mean [SD] age, 66.1 [6.7] years). Mean (SD) follow-up in the full cohort was 36.7 (4.6) months. No statistically significant differences were observed in age, clinical tumor stage, pathological tumor stage, Gleason score, Gleason grade group, preoperative prostate-specific antigen concentration, D'Amico risk classification, and hospital level. A shorter hospital stay was observed for patients undergoing RARP vs those undergoing ORP (mean [SE] difference, -1.64 [0.22] days; P < .001) and LRP (mean [SE] difference, -0.57 [0.23] days; P = .01). Patients undergoing RARP had lower odds of receiving a blood transfusion (RARP vs ORP: adjusted odds ratio [aOR], 0.25; 95% CI, 0.17-0.36; RARP vs LRP: aOR, 0.58; 95% CI, 0.37-0.91). For postoperative pain, RARP was associated with a decrease in the odds of moderate to severe postoperative pain for as long as 12 weeks compared with both ORP and LRP (eg, RARP vs LRP at week 12: aOR, 0.40; 95% CI, 0.19-0.85; P = .02). The aORs for RARP vs those for ORP and LRP in the third year after RP were, for erectile dysfunction, 0.74 (95% CI, 0.45-0.92) and 0.60 (95% CI, 0.36-0.98), respectively; for urinary incontinence, 0.93 (95% CI, 0.65-0.99) and 0.60 (95% CI, 0.42-0.86), respectively; and for hernia, 0.51 (95% CI, 0.31-0.84) and 0.82 (95% CI, 0.46-0.92), respectively.

CONCLUSIONS AND RELEVANCE

In this study, undergoing RARP was associated with fewer acute and chronic postoperative complications than undergoing ORP or LRP.

Oncologic Outcomes of Radical Prostatectomy and High-Dose Intensity-Modulated Radiotherapy with Androgen-Deprivation Therapy for Relatively Young Patients with Unfavorable Intermediate-Risk Prostate Adenocarcinoma

Simple Summary

Scarce reports have evaluated oncologic outcomes in relatively young men with unfavorable intermediate-risk prostate cancer (UIR-PC) receiving radical prostatectomy (RP) or high-dose intensity-modulated radiotherapy (IMRT). After a literature review, we present the leading and largest head-to-head propensity score-matched study to examine all-cause death, biochemical failure (BF), locoregional recurrence (LRR), and distant metastasis (DM) in relatively young men with UIR-PC undergoing RP or high-dose IMRT. After adjustment for confounders, RP was found to be superior to high-dose IMRT in terms of the patients’ overall survival, BF, LRR, and DM.

Abstract

Purpose: To estimate the oncologic outcomes of radical prostatectomy (RP) and high-dose intensity-modulated radiotherapy (IMRT) with short-term androgen-deprivation therapy (ADT) in relatively young men with unfavorable intermediate-risk prostate cancer, as defined by the National Comprehensive Cancer Network (NCCN-UIR-PC). Patients and Methods: We enrolled relatively young men (≤65 years) from the Taiwan Cancer Registry who had been diagnosed as having NCCN-UIR-PC and who had received RP or high-dose IMRT (at least ≥72 Gy) with short-term ADT (4–6 months). After propensity score matching of the confounders, Cox proportional regression was used to model the time from the index date (i.e., date of diagnosis) to all-cause death, biochemical failure (BF), locoregional recurrence (LRR), and distant metastasis (DM). Results: The corresponding adjusted hazard ratios (95% confidence intervals) of the risk of all-cause death, BF, LRR, and DM were 2.76 (1.36–5.60, p = 0.0050), 2.74 (1.72–4.84, p < 0.0001), 1.28 (1.09–1.90, p = 0.0324), and 2.11 (1.40–4.88, p = 0.0052), respectively. Conclusions: RP is superior to high-dose IMRT with short-term ADT in terms of oncologic outcomes for relatively young men with UIR-PC.

Improving the timeliness and accuracy of injury severity data in road traffic accidents in an emerging economy setting

Road traffic injuries (RTIs) are among the leading causes of injury and fatality worldwide. RTI casualties are continually increasing in Taiwan; however, because of a lack of an advanced method for classifying RTI severity data, as well as the fragmentation of data sources, road traffic safety and health agencies encounter difficulties in analyzing RTIs and their burden on the healthcare system and national resources. These difficulties lead to blind spots during policy-making for RTI prevention and control. After compiling classifications applied in various countries, we summarized data sources for RTI severity in Taiwan, through which we identified data fragmentation. Accordingly, we proposed a practical classification for RTI severity, as well as a feasible model for collecting and integrating these data nationwide. This model can provide timely relevant data recorded by medical professionals and is valuable to healthcare providers. The proposed model's pros and cons are also compared to those of other current models.

Longitudinal transition trajectory of gouty arthritis and its comorbidities: a population-based study

The aim of the study was to investigate the longitudinal transition trajectory of gout and its comorbidities in male patients with gout in different age groups. A total of 3973 male patients who received a new diagnosis of gouty arthritis were identified from the Taiwan Longitudinal Health Insurance Database and divided into two age cohorts (<50 and ≥50 years). Each patient was individually followed from 2000 to 2009 to identify associated comorbidities, namely hypertension, hypercholesterolemia, diabetes mellitus, cardiovascular diseases, and chronic kidney disease. Two outcome measurements of stroke and all-cause cancer were further identified until 2010. The transition trajectory was divided into the following five phenotype groups: persistent hypertension combined with a high prevalence of various gout-related comorbidities, persistent hypercholesterolemia combined with a moderate prevalence of various gout-related comorbidities, persistent low prevalence of various gout-related comorbidities, moderate to high prevalence of various gout-related comorbidities, and low to high prevalence of various gout-related comorbidities. Although the younger and older patients had a similar longitudinal transition trajectory of gout-related comorbidities, the older patients had a higher 10-year likelihood of transition from a low or moderate to a high prevalence of various gout-related comorbidities. In addition, the incidences of stroke and all-cause cancer were higher in the groups with high and moderate to high prevalences of various gout-related comorbidities than in the other groups. The occurrence of gouty arthritis in different life stages can cause cluster effects involving varying degrees of comorbidities over time. The findings of the current study can provide additional knowledge and increase clinical awareness regarding the early assessment and management of gout-related comorbidities in clinical practice.

Influenza Vaccination Reduces Hospitalization for Heart Failure in Elderly Patients with Chronic Kidney Disease: A Population-Based Cohort Study

BACKGROUND

Elderly patients with chronic kidney disease (CKD) are at a higher risk of hospitalization for cardiovascular diseases (CVD). Previous studies have reported the beneficial effects of the influenza vaccine in patients with CVD. However, the effects of influenza vaccination on the reduction of hospitalizations for heart failure (HF) in elderly patients with CKD remain unclear.

METHODS

This cohort study comprised elderly patients (≥ 55 years of age) with a recorded diagnosis of CKD (n = 4406) between January 1, 1999 and December 31, 2008. Each patient was followed-up until the end of 2008. The hazard ratio (HR) and 95% confidence interval (CI) for the association between the influenza vaccination and the first HF hospitalization were analyzed. In addition, the patients were categorized into four groups based on their vaccination status (unvaccinated and total number of vaccinations: 1, 2-3, and ≥ 4).

RESULTS

We found that elderly patients with CKD receiving influenza vaccination exhibited a lower risk of HF hospitalization (adjusted HR, 0.31; 95% CI, 0.26-0.39, p < 0.001). The protective effects of influenza vaccination remained consistent regardless of the age group (55-64, 65-74, ≥ 75), sex, and influenza seasonality. When the patients were stratified according to the total number of vaccinations, the adjusted HRs for HF hospitalization were 0.60 (0.47-0.77), 0.30 (0.23-0.41), and 0.10 (0.06-0.16) for patients who received 1, 2-3, and ≥ 4 vaccinations during the follow-up period, respectively.

CONCLUSIONS

The results revealed that elderly patients with CKD receiving annual influenza vaccination are at a lower risk of HF hospitalization.

Influenza Vaccination is Associated with Lower Risk of Acute Coronary Syndrome in Elderly Patients with Chronic Kidney Disease

Elderly patients with chronic kidney disease (CKD) are at a higher risk of hospitalization for cardiovascular diseases (CVD). Previous studies have showed that influenza vaccination could reduce the risk of recurrent major cardiovascular events in patients with CVD. However, the effects of influenza vaccination on the reduction of first hospitalizations for acute coronary syndrome (ACS) in elderly patients with CKD remain unknown.We conducted a cohort study using data from the Taiwan Longitudinal Health Insurance Database 1997 to 2008. This cohort study comprised elderly patients (ages ≥55 years) with a recorded diagnosis of CKD (n = 4406) between January 1, 1999, and December 31, 2007. Each patient was followed up until the end of 2008. To minimize the selection bias of vaccine therapy, a propensity score adjustment was applied. The hazard ratio (HR) and 95% confidence interval (CI) for the association between the influenza vaccination and the occurrence of first hospitalization for ACS was evaluated by Cox proportional hazards regression. We further categorized the patients into 4 groups according to their vaccination status (unvaccinated, and total number of vaccinations: 1, 2-3, and ≥4).We found that elderly CKD patients without prior CVD history receiving influenza vaccination exhibited a lower risk of hospitalization for ACS (adjusted HR = 0.35, 95% CI 0.30-0.42; P < 0.001). We observed consistent protective effects regardless of age groups (55-64, 65-74, and ≥75), gender, and seasonality of influenza. When the patients were stratified according to the total number of vaccinations, the adjusted HRs for first ACS hospitalization were 0.62 (95% CI 0.52-0.81), 0.35 (95% CI 0.28-0.45), and 0.13 (95% CI 0.09-0.19) for patients who received 1, 2 to 3, and ≥4 vaccinations. There was a significant trend of decreasing risk of ACS hospitalization with an increasing number of vaccinations.The results of our observational study could strengthen the annual vaccination policy and physicians should be aware of missed opportunities to vaccinate elderly patients with CKD against influenza. The potential public health impact of influenza vaccination, particularly in the elderly CKD patients without a history of CVD, who are at risk for ACS, should be further explored.

Cancer risk in HBV patients with statin and metformin use: a population-based cohort study

Chronic infection with hepatitis B virus (HBV) often causes chronic inflammation of the liver with an increased incidence of hepatocellular carcinoma (HCC). HBV-infected individuals may also have an increased incidence of nonliver cancers. Taking statin or metformin may decrease inflammation and infiltration, which may, as a result, reduce the risk of liver cancer or other major cancers in patients with HBV infection. The purpose of this study was to evaluate the hypothesis that statin and metformin could reduce the incidence of liver cancer (HCC) or nonliver cancers in patients with HBV.Using the Taiwan Longitudinal Health Insurance Database 2000 to 2008, this cohort study comprised patients with a recorded diagnosis of HBV (N = 71,847) between January 1, 2000 and December 31, 2008. Each patient was followed-up until the end of 2008. The occurrence of HCC or a nonliver cancer was evaluated in patients who either were or were not taking statin or metformin. Cox proportional hazard regressions were used to evaluate the cancer incidence after adjusting for known confounding factors.In total, 71,824 HBV-infected patients comprised the study cohort. Our study showed that either metformin or statin use was associated with a reduction in the incidence of cancer. This was most prominent in patients taking both statin and metformin. The adjusted hazard ratios (HRs) for patients using only statin were 0.52 (95% confidence interval [CI], 0.48-0.57) for all cancers, 0.28 (95% CI, 0.23-0.35) for liver cancer, and 0.63 (95% CI, 0.57-0.70) for nonliver cancers. Patients taking only metformin had risk-adjusted HRs of 0.82 (95% CI, 0.75-0.90) for all cancers, 0.97 (95% CI, 0.84-1.14) for liver cancer, and 0.75 (95% CI, 0.67-0.84) for nonliver cancers. A dose-dependent effect of statin use for chemoprevention was observed for all cancers, including both liver cancer and nonliver cancers. A dose-dependent effect of metformin was also seen in liver cancer and nonliver cancers without stratification into different cumulative daily doses of statin use.This population-based cohort study investigated the protective effect of statin and metformin against cancer events in patients with HBV infection. Our study demonstrated that either statin or metformin served as independent chemopreventive agents with a dose-response effect in reducing the incidence of cancer with a dose-response effect of the agents and an additive or synergistic effect of combining statin and metformin use in reducing the incidence of many cancers.

Emergency department utilization can indicate early diagnosis of digestive tract cancers: A population-based study in Taiwan

BACKGROUND AND OBJECTIVE

Patients who visit emergency department (ED) may have symptoms of occult cancers.

METHODS

We studied a random cohort of one million subjects from Taiwan National Health Insurance Research Database between 2000 and 2008 to evaluate the ED utilization of individuals who were subsequently diagnosed with digestive tract cancers. The case group was digestive tract cancer patients and the control group was traumatic fracture patients. We reviewed record of ED visits only from 4 to 15 months before the cancer diagnoses.

RESULTS

There were 2635 and 6665 in the case and control groups respectively. Patients' adjusted odds ratio with 95% confidence interval for the case group were 1.36 (1.06-1.74) for Abdominal ultrasound, 2.16 (1.61-2.90) pan-endoscopy, 1.72 (1.33-2.22) guaiac fecal-occult blood test, 1.42 (1.28-1.58) plain abdominal X-rays, 1.20 (1.09-1.32) SGOT, 1.27 (1.14-1.40) SGPT, 1.66 (1.41-1.95) total bilirubin, 2.41 (1.89-3.08) direct bilirubin, 1.21 (1.01-1.46) hemoglobin and 3.63 (2.66-4.94) blood transfusion, respectively. Blood transfusion in the ED was a significant predictor of the individual subsequently diagnosed with digestive tract cancer.

CONCLUSIONS

The health system could identify high risk patients early by real-time review of their ED utilization before the diagnosis of digestive tract cancers. We proposed a follow-up methodology for daily screening of patients with high risk of digestive tract cancer by informatics system in the ED.

Critical laboratory result reporting system in cancer patients

HYPOTHESIS

Automatic transmission of computer-generated Critical Laboratory Result Reports (CLRRs) to physicians can improve the care of advanced cancer patients by improving the communication efficacy of important medical information.

METHOD

We followed a cohort of 2012 cancer patients from diagnosis to five years or to death if it occurred before five years from diagnosis. The incidence and number of CLRRs and their association with diagnosis, age, gender, tumor size, and clinical staging were evaluated. The CLRRs that were reported included for example: glucose<40 or>500, hemoglobin<6.0. (Appendix 1)

RESULTS

Two thousand, twelve patients with cancer were included in the study; 45.6 percent had one or more critical laboratory results that required a CLRR. Older patients greater than or equal to 75 years of age had more CLRRs than younger patients. Patients with colorectal, liver, and lung cancer had a significantly higher number of CLRRs. More CLRRs were also seen in late-staged cancers. These conditions also have higher mortality rates.

CONCLUSION

Critical values are common in patients with cancer, especially older patients with advanced disease. They occur more commonly with some cancers of liver and lung cancers. Our data demonstrate that critical laboratory values can be transmitted successfully to physicians. The impact of this system promises to improve the care of these individuals' serious illnesses. A prospective study to demonstrate the benefit of this system is being planned.

Comorbidity as an independent risk factor in patients with cancer: an 8-year population-based study

This study determined the prevalence of medical conditions in patients with cancer and their impact on outcome. We evaluated a cohort of 37,411 patients diagnosed with cancer between 2000 and 2008 in Taiwan, collecting the cancer diagnosis and chronic disease diagnoses. The severity of the comorbid condition was correlated with the cancer diagnosis and outcome. Overall, 71.9% of the study population had 1 or more comorbid conditions. Patients with none (n = 10 508), 1 (n = 8881), 2 (n = 6583), and 3 or more (n = 11 439) comorbid conditions had mortality rates of 11.49%, 15.99%, 19.61%, and 29.39%, respectively. Older patients with comorbid conditions had a significantly higher chance of death. Dementia, heart disease, or cerebrovascular diseases were associated with the highest mortality. Cancer patients with comorbid conditions have a significantly higher risk of death. Prevention and better medical management of comorbid conditions is likely to result in improved outcomes for patients with cancer.

Safety portal: the safest goes through the air--ubiquitous high-risk reminders bridging out the patient safety in emergency department

Under the safety net of hospital-based patient safety informatics (PSI) system, RFID is build to adapt emergency department safety needs and the process improvement activities. We implemented the RFID framework as the electronic patient identifier into the process improvement of ED workflow; it defined as the safety portal to introduce PSI safety features on the real-time basis.

METHODS

Since 2004, we were applying RFID technology into a 200 daily visits emergency department of the regional medical center in Taipei, Taiwan. We then developed wireless web-based RFID safety portal to implement the real-time safety reminders such as the laboratory and radiology reports to the physician who can make decision promptly to the patients in the ED.

RESULTS

Under the ED safety portal, the diagnosis time for physicians to make clinical decision is largely reduced nearly 40 percent due to the safety enhancement RFID system. ED physician who could actively receive patient's updated clinical data to make clinical decision via web-based informatics system reasonably decreases.

CONCLUSIONS

The effectiveness of RFID system not only enhance patient identification during ED process but combine ED safety net which providing needed data for ED physician and staff who visit ED patients with valuable real-time data on time. Patient safety on ED can be clearly improved from the embracing modern technology and build up a patient centered ED environment.

Sequential, cycling maintenance therapy for post transplant multiple myeloma

High-dose chemotherapy with autologous stem cell transplantation in patients with newly diagnosed multiple myeloma can prolong survival but is not curative. Maintenance therapy post transplant may prolong the disease-free interval and impact overall survival. We have conducted a phase II pilot study of 28 post transplant myeloma patients treated with a sequential, cycling maintenance regimen. The regimen was designed to include a variety of active myeloma agents chosen for ease of administration to enhance patient compliance and scheduled sequentially to minimize toxicity. The 12-month cycling schedule included dexamethasone (months 1-3); melphalan and prednisone (months 4, 5); cyclophosphamide and prednisone (months 6, 7); alpha-interferon (months 8-10); followed by a drug holiday (months 11, 12). The regimen was generally well tolerated with five patients developing reversible grade III-IV toxicity (diabetes-induced hyperglycemia in four, neutropenia in one). There was one toxic death on study due to non-neutropenic pneumonia and sepsis. Median event-free survival from transplant was 36.9 months (95% CI 23.6 - upper limit not yet reached) with median overall survival not yet reached at a median follow-up of 44 months. This concept of cycling, sequential maintenance with various agents, perhaps including newer biological, targeted agents, warrants further investigation in multiple myeloma.

Pervasive Observation Medicine: The Application of RFID to Improve Patient Safety in Observation Unit of Hospital Emergency Department

Over the past decade, observation medicine has become an important component of emergency medicine. There are several settings in which observation medicine has been useful and valuable.(1) RFID as the patient identification, not only generates the on-line laboratory data and radiology report via hand-held wireless PDA, this RFID system help physician stream-line patient admission to acute bed or ICU in the emergency department more effectively.

Using mobile technology to improve healthcare service quality

Improving healthcare service quality for illness of treatment, illness prevention and patient service is difficult for most hospitals because the hospitals are lack adequate resources and labor. In order to provide better healthcare service quality for patients, mobile technology can be used to manage healthcare in a way that provides the optimal healthcare service for patients. Pursuing utilization of mobile technology for better patient service, Taipei Medical University Municipal W. F. Teaching Hospital has implemented a mobile healthcare service (m-HS) system to increase healthcare service quality. The m-HS system improves the quality of medical care as well as healthcare service. The m-HS is a multi-functional healthcare management agent, meets the mobile tendency of the present society. This study seeks to discuss the m-HS architecture and workflow processes. We believe the m-HS does have the potential to improve healthcare service quality. Finally, the conclusions and suggestions for the m-HS are given.

Treatment for Waldenstrom’s macroglobulinemia

Waldenstrom's macroglobulinemia is a rare form of indolent lymphoma characterized by the production of a monoclonal immunoglobulin M protein, and complications such as hyperviscosity, cytopenias and peripheral neuropathy. Conventional treatment approaches are based on alkylators or nucleoside analogs, but in the absence of a clearly superior regimen, a broad array of alternative therapies exists. Choices range from biological agents to combination chemotherapy to stem-cell transplantation. A rational approach therefore must be based on careful patient assessment and individualization of therapy.

Intermediate dose thalidomide (200 mg daily) has comparable efficacy and less toxicity than higher doses in relapsed multiple myeloma

Thalidomide at doses >200 mg has 100% grade 1-2 and 25% grade 3-4 toxicities requiring discontinuation. We report a retrospective study of relapsed myeloma patients treated with thalidomide 200 mg with no dose escalation. Thirty patients were identified; 43% of patients responded with paraprotein decline >75% -- 2 (6%), 50-75% -- 7 (23%), 25-50% -- 4 (14%) and 2 (6%) were stable. All five patients with 13q deletion responded. Only 54% reported grade 1-2 toxicities (none reporting > grade 2) with 5 (17%) discontinuing treatment due to toxicity. Thalidomide 200 mg daily with no dose escalation appears as effective and better tolerated than escalated doses for relapsed myeloma patients.

'Relative' chemotherapy sensitivity: the impact of number of salvage regimens prior to autologous stem cell transplant for relapsed and refractory aggressive non-Hodgkin's lymphoma

The purpose of the study was to assess the impact of number of salvage regimens needed to demonstrate chemotherapy sensitivity on relapse rates, survival, and toxicity following high-dose therapy and autologous bone marrow transplantation (ABMT) in relapsed or refractory non-Hodgkin's lymphoma. We retrospectively reviewed 136 patients with intermediate-grade lymphoma who underwent ABMT. All patients were treated with salvage therapy to maximum tumor reduction. Three quarters (102/136) of the patients received one salvage regimen, while 31 (23%) patients received two or more regimens. When compared to patients requiring >or= two regimens, patients requiring only one salvage regimen to demonstrate chemosensitivity were more likely to have a longer previous CR from initial therapy (CR >or=12 months in 47% vs 26%; P = 0.04) and to have attained CR with salvage (54% vs 16%; P = 0.001). Both median relapse-free survival (RFS) and overall survival (OS) have not yet been reached in patients receiving one salvage regimen (median follow-up 50.6 months). This is superior to the median RFS of 9.1 months (P = 0.004) and OS of 11.1 months in patients requiring >or=two regimens to demonstrate chemosensitivity (P = 0.002). Time to engraftment, toxic deaths and incidence of myelodysplasia were similar in the groups. The survival rate observed in patients requiring >or=two salvage regimens, although inferior to that of patients receiving a single salvage regimen, are still generally superior to results in the literature for patients treated with chemotherapy alone without ABMT. We conclude that high-dose therapy with ABMT is appropriate for lymphoma patients even when disease reduction requires repeated numbers of salvage regimens.

Selective termination of aneuploidy utilizing rapid fluorescence in situ hybridization detection techniques

Twin pregnancy following assisted reproductive technology with a euploid fetus and a coexisting aneuploid co-twin constitutes a conflicting situation; therefore, it is important for the genetic constitution of each co-twin to be diagnosed accurately and promptly for parental genetic counseling and subsequent aggressive management. A 35-year-old woman, gravida 1, with a 2-year history of infertility, presented bilateral fallopian tubal obstruction at her infertility workups, for which she received in vitro fertilization; subsequently she conceived a twin pregnancy. She underwent genetic amniocentesis at 16 weeks' gestation, as indicated by an advanced maternal age. Presented with the diagnosis of twin pregnancy with discordancy for trisomy 21, a rapid fluorescence in situ hybridization (FISH) technique for aneuploidy mapping was applied for subsequent abdominal selective fetal reduction. The FISH technique facilitates the rapid analysis of uncultured amniocytes. Normal (disomic) and trisomic samples can be distinguished clearly and rapidly for subsequent selective fetocide. The FISH technique is an important tool in prenatal diagnosis and clinical applications.

Autotransplants for histologically transformed follicular non-Hodgkin's lymphoma

Histological transformation from a follicular non-Hodgkin's lymphoma (NHL) to a higher grade lymphoma carries a poor prognosis despite treatment with aggressive anthracycline-based chemotherapy. We retrospectively analysed 35 patients with histologically transformed NHL who underwent high-dose therapy and autotransplantation at our centre. Patients up to 65 years old were eligible for autotransplant at the time of transformation or with subsequent relapses, provided that chemosensitivity to a salvage regimen could be demonstrated. All patients received high-dose therapy [etoposide 60 mg/kg, melphalan 160 mg/m2 and fractionated total body irradiation (TBI) 12 Gy] followed by unpurged autologous bone marrow or blood stem cell rescue. Most patients (69%) had advanced stage disease (stages 3--4) at transformation and bone marrow involvement was common (49%). Twenty-six (74%) patients were in partial remission (PR) and nine (26%) in complete remission (CR) at the time of transplant. Median duration from transformation to transplant was 10.9 months (range, 5.2 months--4.6 years). At a median follow up of 52 months after autotransplant, 19 (54%) patients had died. Causes of death were progressive lymphoma in nine patients (26%), treatment-related mortality (TRM) in seven (20%) and myelodysplasia in three (8%). Only five patients in our cohort were > 60 years old, but all died as a result of treatment-related causes (mostly pulmonary infections). Five-year overall survival and progression-free survival from time of transplant were 37% and 36% respectively. Using multivariate analysis of factors including gender, age, stage, extranodal disease, disease bulk, B symptoms, number of prior therapies, relapse status and CR/PR status at transplant, only advanced age significantly predicted for survival from autotransplant (P = 0.002). Our survival data are comparable to previous reports of autotransplantation for transformed NHL and suggest a benefit over standard chemotherapy alone in selected patients. However, our high TRM cautions the use of aggressive therapy, including TBI, in patients over 60 years old.

Radiation-associated pneumonitis following autologous stem cell transplantation: predictive factors, disease characteristics and treatment outcomes

High-dose therapy followed by autologous stem cell transplantation (ASCT) prolongs survival in patients with multiple myeloma and is relatively safe with treatment-related mortality rates of only 1-5%. Interstitial pneumonitis (IP) is normally an infrequent complication of ASCT with a reported incidence of 0-16%. Between 1992 and 1998, 94 myeloma patients at our center underwent ASCT using a high-dose regimen of etoposide (60 mg/kg), melphalan (160 mg/m2) and fractionated TBI 12 Gy. An unusually high incidence of IP (29/94 (31%)) was noted. Mortality in the IP patients was high at 45%. Patients developing IP were more frequently anemic than those who did not have pulmonary complications (hemoglobin <100 g/l) prior to transplant (P = 0.03) but no other pre-transplant factors were predictive (ie age, gender, smoking history, CMV status, pulmonary function, creatinine, beta2-microglobulin or C-reactive protein, prior cumulative chemotherapy or chest irradiation). A significantly lower IP rate was noted in 32 contemporaneous myeloma control patients conditioned with BU-CY without TBI at our center (3/32 (9%); P=0.03) and in 32 lymphoma control patients conditioned with the same melphalan and etoposide regimen minus the TBI (2/32 (6%); P = 0.003). In contrast, when using the same TBI-containing regimen in 32 concurrently treated lymphoma patients, an increase in IP similar to that seen in our myeloma cohort (7/32 (22%); P = 0.3) was noted. This strongly suggests that TBI is the predominant factor contributing to lung toxicity. We conclude that radiation-associated pneumonitis cannot be easily predicted by pretransplant variables. Therefore surveillance, early recognition and prompt therapy are recommended.

A comparison of elderly patients with aggressive histology lymphoma who were entered or not entered on to a randomized phase II trial

The purpose of this study was to compare the baseline patient characteristics, treatments and outcomes of elderly patients with aggressive histology lymphoma who were entered or not entered onto a randomized phase II trial. We previously conducted a randomized phase II trial in patients > or = 65 years of age who had advanced stage intermediate grade lymphoma. A registry of all patients meeting the inclusion criteria for that trial was maintained. Many patients were not entered on to the randomized trial because of the presence of at least one exclusion criterion, or because of patient or physician choice. We have compared the baseline characteristics, treatment, and survival of the randomized and non-randomized patients. Results show that 68 consecutive patients met inclusion criteria for the randomized trial. Thirty-eight patients satisfied all eligibility criteria, consented, and were randomized; 30 patients (44%) were not entered. In comparison with randomized patients, non-randomized patients were older (mean 75.9 vs. 72.4 years; P=0.013), had a poorer performance status (P=0.0006), were less likely to be given treatment with curative intent (60% vs. 100%; P<0.001), and were less likely to complete 6 cycles of such treatment (27% vs. 89%; P<0.001). With a median follow-up of > 7 years, actuarial 5-year survival is superior in randomized patients (44.3% vs. 10%; P<0.00001). In conclusion, a substantial number of patients did not enter our randomized trial phase II trial and had different characteristics, received different therapy and had inferior outcomes in comparison with randomized patients. Randomized trials of therapy for elderly lymphoma patients may include special selection criteria and results may not be generalizable to a substantial proportion of other older patients.

Birth after the injection of sperm and the cytoplasm of tripronucleate zygotes into metaphase II oocytes in patients with repeated implantation failure after assisted fertilization procedures

OBJECTIVE

To assess the technique of injecting a single sperm and cytoplasm obtained from tripronucleate zygotes into metaphase II oocytes for the treatment of patients with repeated implantation failure after intracytoplasmic sperm injection or IVF.

DESIGN

Clinical study.

SETTING

Private infertility clinic.

PATIENT(S)

Patients with repeated implantation failure after intracytoplasmic sperm injection or IVF.

INTERVENTION(S)

The metaphase II oocytes of recipients were injected with their husbands' spermatozoa and cytoplasm aspirated from the tripronucleate zygotes of donors.

MAIN OUTCOME MEASURE(S)

Fertilization after cytoplasm and sperm injection, embryo development, and successful pregnancy.

RESULT(S)

In total, 62 metaphase II oocytes from nine recipients were injected. Of the 62 injected oocytes, 3 (5%) degenerated and 43 (69%) had two pronuclei 18 hours after injection. Thirty-nine oocytes with two pronuclei cleaved to the two-cell to six-cell stage after another 24 hours of culture. All cleaved embryos were transferred into the uteruses of recipients. Four clinical pregnancies occurred in four recipients. No abnormal chromosomes were observed after amniocentesis and karyotyping in all pregnancies. Five healthy infants were born.

CONCLUSION(S)

Injection of the cytoplasm of tripronucleate zygotes may enhance the clinical pregnancy rate in patients with repeated implantation failure after intracytoplasmic sperm injection or IVF.

Early alteration of coronary hemodynamics in late restenosis after coronary angioplasty

It is not known whether changes in coronary hemodynamics may antedate the development of restenosis after percutaneous coronary transluminal angioplasty (PTCA). The purpose of this study was to evaluate the early change in coronary microvascular function in patients with late restenosis after PTCA. Coronary hemodynamics were studied in series before, immediately after, 2 weeks and 3 months after successful PTCA in 12 male patients with a single lesion of the left anterior descending coronary artery. In each patient, great cardiac venous flow (GCVF) and oxygen content were measured both at baseline and during hyperemia induced by adenosine infusion. The sequential changes of coronary hemodynamics were compared between patients with and without restenosis at 3 months after PTCA. Basic characteristics did not differ between the patients with (n = 6) and those without restenosis (n = 6). Luminal diameter stenosis (in percentage) was also similar between the two groups both before (79.2 +/- 18.4% vs 83.0 +/- 9.6%, p = NS) and up to 2 weeks after PTCA (25.8 +/- 10.9% vs 28.5 +/- 7.9%, p = NS). In patients without restenosis, basal and hyperemic GCVF was unchanged up to 2 weeks after PTCA. There was a significant increase in CFR 3 months after PTCA. In patients with restenosis, basal GCVF was significantly increased and hyperemic GCVF was unchanged immediately after PTCA. However, 2 weeks after PTCA, basal GCVF was decreased while luminal diameter was still preserved. In comparison with those without restenosis, patients with restenosis had significantly lower CFR before (1.98 +/- 0.42 vs 2.69 +/- 0.46, p = 0.019), immediately after (1.47 +/- 0.27 vs 2.24 +/- 0.47, p = 0.006) and 3 months after PTCA (1.51 +/- 0.32 vs 3.40 +/- 0.54, p = 0.001). In patients without restenosis, the recovery of coronary microvascular function was delayed up to 3 months after PTCA. In patients with late restenosis, basal coronary microvascular tone was altered within 2 weeks after PTCA suggesting early deterioration of coronary microvascular function before the development of angiographic restenosis.

Natural mass infection by heterophyid metacercariae in aquacultured Japanese eel in Taiwan

A natural mass infection of heterophyid metacercariae in aquacultured Japanese eel Anguilla japonica in Taiwan was observed. Of the 28,000 adult eels in 2 ponds, about 25,000 (90%) showed swollen, cloudy and white eyes. Although morbidity was about 90%, there was no mortality among the affected eels. Histopathological sections showed edema and hemorrhage of the eye. Numerous metacercariae were observed in the muscle tissues around the eyeball, the subcutaneous tissue and even in the cartilage. Of the 6 eels digested with artificial gastric juice, all were found to contain metacercariae in their muscle tissues. The average number of metacercariae recovered from the 6 eels was 1219, with a range of 50 to 3762. These metacercariae, when fed orally to immunodeficient (scid) mice, developed into adult worms which were identified as Procerovum cheni Hsu 1950. The naturally infected eels were transferred to a new pond without snails and their eye lesions were not apparent anymore after 2 wk. In a follow-up investigation, 19 of 20 apparently healthy eels in a nearby aquaculture farm were found to harbour metacercariae in their muscles. However, the number of the metacercariae ranged from 1 to 14, with an average of 4.21. This is the first report of heterophyid metacercariae causing mass morbidity in aquacultured eels.

Studies of multimerin in patients with von Willebrand disease and platelet von Willebrand factor deficiency

In normal platelet alpha-granules von Willebrand factor (VWF) is stored with multimerin and factor V in an eccentric electron-lucent zone. Because the platelet stores of VWF are deficient in 'platelet low' type 1 and type 3 von Willebrand disease (VWD), we investigated their electron-lucent zone proteins. The patients with VWD had partial to complete deficiencies of plasma and platelet VWF but normal alpha-granular multimerin and factor V, and normal alpha-granular fibrinogen, thrombospondin-1, fibronectin, osteonectin and P-selectin. In type 3 VWD platelets, alpha-granular electron-lucent zones lacking VWF-associated tubules were identified and multimerin was found in its normal alpha-granular location. These findings indicate that the formation of the electron-lucent zone and the sorting of multimerin to this region occur independent of VWE The isolated abnormalities in VWF suggests a VWF gene mutation is the cause of 'platelet low' type 1 VWD.

Metacercariae in fishes of Sun Moon lake which is an endemic area for Clonorchis sinensis in Taiwan

The Sun Moon lake in Central Taiwan is a known endemic area for clonorchiasis. Of the 45 fresh water fish, Hemiculter leucisculus, from the lake that were examined by artificial gastric juice digestion in October 1995, all were found to harbor metacercariae in their muscle. The number of metacercariae isolated from each fish ranged from 2 to 2,185, with an average of 254. A total of 11,443 metacercariae was collected from the 45 fish. Of the 4,223 metacercaria that were examined under light microscope, 4,064 (96.23%) were found to belong to Haplorchis taichui, 90(2.13%) to H. pumilio, 2(0.05%) to C. sinensis and 67 (1.59%) to unknown species due to the metacercariae being not yet developed or immature. The 2 C. sinensis metacercariae were obtained from 2 out of 45 fish examined. Our results contrast with reports of a decade ago which stated that all the fish of the Sun Moon lake examined were positive for C. sinensis. Possible reasons for the decrease of C. sinensis metacercariae are the disappearance of pig farms around the lake, increased awareness of the trematode by the lakeside inhabitants and probably the exclusive use of mammals as its definitive host by C. sinensis. In contrast, besides mammals, Haplorchis spp also use birds as their definitive hosts.

A high-performance double-crystal monochromator soft X-ray beamline

A high-performance double-crystal-monochromator soft X-ray (DCMSX) beamline has been constructed at the Synchrotron Radiation Research Center (SRRC). This beamline delivers monochromatic photon beams with energies from 1 to 9 keV and a resolving power (E/DeltaE) of up to 7000. This beamline provides users with an opportunity to study many important materials, such as high-T(c) superconductors, magnetic materials, catalysts, super-alloy compounds etc. Excellent EXAFS and NEXFS spectra have been routinely obtained from this beamline. Several interesting research projects are currently being conducted at this beamline. All the results show that this beamline has been constructed to meet its design goals.

New stenosis on proximal coronary segment after directional atherectomy. Two case reports

Two patients with new coronary stenotic lesions subsequently developed proximal to the sites accepting directional coronary atherectomy (DCA) are reported. One lesion developed at the left main coronary artery and the other at the proximal segment of the left anterior descending artery. The mechanisms of the development of such new stenotic lesions after DCA were studied and procedure-related mechanical trauma over the proximal segment of the primary lesion may be the possible mechanism for such complication.

Thermophilic biodegradation of BTEX by two consortia of anaerobic bacteria

Two thermophilic anaerobic bacterial consortia (ALK-1 and LLNL-1), capable of degrading the aromatic fuel hydrocarbons, benzene, toluene, ethylbenzene, and the xylenes (BTEX compounds), were developed at 60 degrees C from the produced water of ARCO'S Kuparuk oil field at Alaska and the subsurface water at the Lawrence Livermore National Laboratory gasoline-spill site, respectively. Both consortia were found to grow at 45-75 degrees C on BTEX compounds as their sole carbon and energy sources with 50 degrees C being the optimal temperature. With 3.5 mg total BTEX added to sealed 50-ml serum bottles, which contained 30 ml mineral salts medium and the consortium, benzene, toluene, ethylbenze, m-xylene, and an unresolved mixture of o- and p-xylenes were biodegraded by 22%, 38%, 42%, 40%, and 38%, respectively, by ALK-1 after 14 days of incubation at 50 degrees C. Somewhat lower, but significant, percentages of the BTEX compounds also were biodegraded at 60 degrees C and 70 degrees C. The extent of biodegradation of these BTEX compounds by LLNL-1 at each of these three temperatures was slightly less than that achieved by ALK-1. Use of [ring-14C]toluene in the BTEX mixture incubated at 50 degrees C verified that 41% and 31% of the biodegraded toluene was metabolized within 14 days to water-soluble products by ALK-1 and LLNL-1, respectively. A small fraction of it was mineralized to 14CO2. The use of [U-14C]benzene revealed that 2.6%-4.3% of the biodegraded benzene was metabolized at 50 degrees C to water-soluble products by the two consortia; however, no mineralization of the degraded [U-14C]benzene to 14CO2 was observed. The biodegradation of BTEX at all three temperatures by both consortia was tightly coupled to sulfate reduction as well as H2S generation. None was observed when sulfate was omitted from the serum bottles. This suggests that sulfate-reducing bacteria are most likely responsible for the observed thermophilic biodegradation of BTEX in both consortial cultures.

Coronary microvascular dysfunction is associated with ischemic-like electrocardiogram during exercise in patients with anginal chest pain and normal coronary angiograms

To determine the possible mechanism of the ischemic-like electrocardiogram (ECG) during exercise in the presence of anginal chest pain and normal coronary angiograms, both a treadmill exercise test (TET) and coronary hemodynamic study were prospectively performed in 33 consecutive patients (18 females and 15 males, aged 48 +/- 10 years) with angina of unknown cause. Although baseline characteristics and coronary hemodynamics were similar between patients with (TET+, n = 17) and those without (TET-, n = 16) ischemic-like ECG during TET, effort angina was more frequently seen in the former group (p < 0.01). Compared to TET- patients, TET+ patients had a significantly lower maximum great cardiac vein flow (GCVF, 108.8 +/- 47.0 vs 146.4 +/- 23.4 ml/min, p = 0.007), higher minimum coronary vascular resistance (0.94 +/- 0.41 vs 0.61 +/- 0.09 mmHg/ml/min., p = 0.003), and lower corrected GCVF (GCVF/rate-pressure product, 0.0087 +/- 0.0036 vs 0.0125 +/- 0.0019, p = 0.001) after dipyridamole infusion (0.56 mg/kg for 4 min). Though coronary flow reserve was significantly lower in TET+ than in TET- patients (2.26 +/- 0.59 vs 3.08 +/- 0.48, p = 0.0001), myocardial oxygen consumption and myocardial efficiency (rate-pressure product/myocardial oxygen consumption) were still similar between these two groups after dipyridamole infusion. Thus, coronary microvascular dysfunction rather than altered cardiac metabolism could contribute to effort angina and ischemic-like ECG during exercise in patients with anginal chest pain and normal coronary angiograms.

Peroxisomal activation of long- and very long-chain fatty acids in the yeast Pichia pastoris

In mammals, beta-oxidation of very long-chain fatty acids (VLCFA) takes place in peroxisomes. This process is impaired in X-linked adrenoleukodystrophy (XALD) patients as a result of decreased activity of peroxisomal very long-chain acyl-CoA synthetase (VLCS). We investigated VLCFA and long chain fatty acid (LCFA) activation in the yeast Pichia pastoris. Both VLCFA and LCFA were activated to their CoA derivatives in an organelle fraction. When organelles were fractionated on a sucrose gradient, VLCS activity co-localized with peroxisomes while long chain acyl-CoA synthetase activity associated primarily with mitochondria. Consistent with these findings, only VLCS activity was reduced in organelle fractions from peroxisome assembly (pas) mutants. Furthermore, no VLCS activity was detected in pas mutants at the density of normal peroxisomes. Thus, we conclude that VLCS is a peroxisomal enzyme in P. pastoris and this organism may serve as an excellent model system to investigate the molecular basis of XALD.

Comparison of respiratory activity and culturability during monochloramine disinfection of binary population biofilms

Biofilm bacteria challenged with monochloramine retained significant respiratory activity, even though they could not be cultured on agar plates. Microbial colony counts on agar media declined by approximately 99.9% after 1 h of disinfection, whereas the number of bacteria stained by a fluorescent redox dye experienced a 93% reduction. Integrated measures of biofilm respiratory activity, including net oxygen and glucose utilization rates, showed only a 10 to 15% reduction. In this biofilm system, measures of microbial respiratory activity and culturability yielded widely differing estimates of biocide efficacy.

Cytoplasmic CD3+ surface CD8+ lymphocytes develop as a thymus-independent lineage in chick-quail chimeras

We have analyzed the embryonic development of a population of lymphoid cells that express a CD3 antigenic determinant in the cytoplasm but not on the cell surface. Since these cells lack T cell receptor (TcR) molecules, we have provisionally named them TCRO cells. Their development, expansion and distribution was investigated following transplantation of splenic and bursal fragments from chicken embryos into quail embryos. Since quail cells are not recognized by our panel of monoclonal antibodies against chicken TcR1, TcR2, TcR3, CD3, CD4 and CD8 molecules, these antibodies provided reliable markers for donor chick lymphocytes in the tissues of the quail recipients. Transplanted spleen and bursa both generated CD3+ cells, the number of which increased as a function of age. Notably, approximately half of these CD3+ cells expressed surface CD8, but none acquired TcR1 (gamma/delta), TcR2 (alpha/beta) or TcR3 expression. Since TCRO cells normally appear first in the spleen of 8-day chick embryos (E8), their generation in E6 splenic transplants indicated an extrathymic origin. The TCRO cells of chick splenic origin migrated to the spleen, bursa and thymus of the quail recipients. In six of seven chimeras acquiring CT3+ cells in the recipient thymus, these cells were restricted to the medulla and displayed the typical TCRO phenotype: CD3+CD8+TcR1-TcR2-TcR3-. These intrathymic TCRO cells also lacked the CT1 thymocyte antigen. We conclude that the TCRO cells represent a thymus-independent lineage of lymphoid cells that can migrate into a receptive thymus by rarely, if ever, differentiate into conventional T cells.

Prevalence and significance of group B Streptococcus in a large obstetric population

Between Jan. 1 and Dec. 31, 1985, vaginal swabs were obtained for culture for group B beta-hemolytic Streptococcus (GBS) from 3078 women admitted for labour and delivery to Regina General Hospital. Seventy-one women had positive results; thus, the colonization rate was only 2.3%. The charts of the 71 women and their 73 babies were analysed. Of the 58 babies from whom swabs were obtained, 20 had GBS at one or more sites; the transmission rate was therefore 34%. Early-onset GBS disease developed in one infant. Two infants died within the first month; however, death was not directly attributable to GBS. Higher rates of preterm delivery and of low birth weight were noted among the babies of the colonized women than among the babies of all women admitted for labour and delivery in 1985. Given the low rate of GBS disease in our centre, we suggest that emphasis be placed on GBS as a possible source of obstetric complications such as preterm labour.