Lessons Learned from a Novel Three-year Longitudinal Stepwise "Residents-as-Teachers" Program

BACKGROUND

Most residents-as-teachers (RaT) programs are delivered over days to weeks without comprehensive evaluation, and stepwise approaches have rarely been applied to RaT activities.

OBJECTIVE

This study aimed to depict the implementation experience and evaluate the effectiveness of a novel longitudinal three-year, stepwise RaT program.

METHODS

The longitudinal RaT program included three once yearly face-to-face courses according to the different teaching roles of the residents. To evaluate the effectiveness of the new longitudinal program, we designed a randomized controlled study for first-year residents of all specialties in one medical center. The effectiveness was evaluated by the objective structured teaching exercise (OSTE), feedback from participants and medical students, and evaluation of clinical practice performance by program directors.

RESULTS

A total of 35 (37.6%) of 93 residents participated in this study, and 13 (37.1%) of all enrolled residents completed all three-year courses, including seven for the longitudinal program and six for the traditional. The serial OSTE revealed significantly higher scores in the longitudinal group in the second and third years (13.43 vs. 9.50, p=0.001 and 14.29 vs. 10.33, p=0.015). Satisfaction was higher when advanced topics were taught in the second and third years compared with those taught in the first year (4.43 vs. 3.89, p=0.02). The feedback from medical students was similar between the two groups, and the evaluation from program directors revealed insignificantly better clinical performance among the longitudinal course participants.

CONCLUSION

It is challenging to conduct a multi-year longitudinal RaT program on young residents. Nevertheless, this longitudinal program was potentially associated with better learning retention and higher satisfaction and worthy to be promoted.

Impaired function of skeletal stem cells derived from growth plates in ovariectomized mice

INTRODUCTION

Mouse skeletal stem cells (mSSCs, CD45^-Ter119^-Tie2^-CD51⁺Thy^-6C3^-CD105^-CD200⁺population) are identified in growth plates (GP) and play important roles in bone regeneration. However, the role of mSSCs in osteoporosis remains unclear.

MATERIALS AND METHODS

The GP were stained by HE staining, and the mSSC lineage was analyzed by flow cytometry at postnatal of 14 days and 30 days in wild-type mice. The mice (8 weeks) were either sham operated or ovariectomy (OVX) and then sacrificed at 2, 4 and 8 w. The GP were stained by Movat staining, and mSSC lineage was analyzed. Then, mSSCs were sorted by fluorescence-activated cell sorting (FACS); the clonal ability, chondrogenic differentiation and osteogenic differentiation were evaluated, and the changed genes were analyzed by RNA-seq.

RESULTS

The percentage of mSSCs were decreased with the narrow GP. Heights of GP were decreased significantly in 8w-ovx mice compared with 8w-sham mice. We found the percentage of mSSCs were decreased in mice at 2w after ovx, but the cell numbers were not changed. Further, the percentage and cell numbers of mSSCs were not changed at 4w and 8w after ovx. Importantly, the clonal ability, chondrogenic differentiation and osteogenic differentiation of mSSCs were impaired at 8w after ovx. We found 114 genes were down-regulated in mSSCs, including skeletal developmental genes such as Col10a1, Col2a1, Mef2c, Sparc, Matn1, Scube2 and Dlx5. On the contrary, 526 genes were up-regulated, including pro-inflammatory genes such as Csf1, Nfkbla, Nfatc2, Nfkb1 and Nfkb2.

CONCLUSION

Function of mSSCs was impaired by up-regulating pro-inflammatory genes in ovx-induced osteoporosis.

Medical school grades may predict future clinical competence

BACKGROUND

In real-world medical education, there is a lack of reliable predictors of future clinical competencies. Hence, we aim to identify the factors associated with clinical competencies and construct a prediction model to identify "improvement required" trainees.

METHODS

We analyzed data from medical students who graduated from National Yang-Ming University with clerkship training and participated in the postgraduate year (PGY) interview at Taipei Veterans General Hospital. Clinical competencies were evaluated using grades of national objective structured clinical examination (OSCEs). This study used data from medical students who graduated in July 2018 as the derivation cohort (N = 50) and those who graduated in July 2020 (n = 56) for validation.

RESULTS

Medical school grades were associated with the performance of national OSCEs (Pearson r = 0.34, p = 0.017), but the grades of the structured PGY interviews were marginally associated with the national OSCE (Pearson r = 0.268, p = 0.06). A prediction model was constructed to identify "improvement required" trainees, defined: trainees with the lowest 25% of scores in the national OSCEs. According to this model, trainees with the lowest 25% medical school grades predicted a higher risk of the "improvement required" clinical performance (Q1-Q3 vs Q4 = 15% vs 60%, odds ratio = 8.5 [95% confidence interval = 1.8-39.4], p = 0.029). In the validation cohort, our prediction model could accurately classify 76.7% "improvement required" and "nonimprovement required" students.

CONCLUSION

Our study suggests that interventions for students with unsatisfactory medical school grades are warranted to improve their clinical competencies.

Comparison of OSCE performance between 6- and 7-year medical school curricula in Taiwan

BACKGROUND

The year 2013 marks a watershed in the history of medical education in Taiwan. Following Taiwan's Taskforce of Medical School Curriculum Reform recommendations, the medical school curriculum was reduced from 7 to 6 years. This study aimed to analyze the impact of medical school curriculum reform on medical students' performance in objective structured clinical examinations (OSCEs).

METHODS

We retrospectively analyzed the OSCE records at Taipei Veterans General Hospital (Taipei VGH), one of Taiwan's largest tertiary medical centers, between November 2016 and July 2020. The eligibility criteria were medical students receiving a full one-year clinical sub-internship training at Taipei VGH and in their last year of medical school. All medical students received a mock OSCE-1 at the beginning of their sub-internship, a mock OSCE-2 after six months of training, and a national OSCE at the end of their sub-internship. The parameters for performance in OSCEs included "percentage of scores above the qualification standard" and "percentage of qualified stations."

RESULTS

Between November 2016 and July 2020, 361 undergraduates underwent clinical sub-internship training at Taipei VGH. Among them, 218 were taught under the 7-year curriculum, and 143 were instructed under the 6-year curriculum. Based on baseline-adjusted ANCOVA results, medical students under the 7-year curriculum had a higher percentage of scores above the qualification standard than those under the 6-year curriculum at the mock OSCE-1 (7-year curriculum vs. 6-year curriculum: 33.8% [95% CI 32.0-35.7] vs. 28.2% [95% CI 25.9-30.4], p < 0.001), and mock OSCE-2 (7-year curriculum vs. 6-year curriculum: 89.4% [95% CI 87.4-91.4] vs. 84.0% [95% CI 81.5-86.4], p = 0.001). Moreover, medical students in the 7-year curriculum had a higher percentage of qualified stations in mock OSCE-1 (7-year curriculum vs. 6-year curriculum: 89.4% [95% CI 87.4-91.4] vs. 84.0% [95% CI 81.5-86.4], p = 0.001) and mock OSCE-2 (7-year curriculum vs. 6-year curriculum: 91.9% [95% CI 90.1-93.8] vs. 86.1% [95% CI 83.8-88.3], p = 0.001). After clinical sub-internship training, there were no differences in the percentage of scores above the qualification standard (7-year curriculum vs. 6-year curriculum: 33.5% [95% CI 32.2-34.9] vs. 34.6 [95% CI 32.9-36.3], p = 0.328) and percentage of qualified stations (7-year curriculum vs. 6-year curriculum: 89.4% [95% CI 88.1-90.7] vs. 90.2% [95% CI 88.6-91.8], p = 0.492).

CONCLUSIONS

At the beginning of the sub-internship, medical students under the 7-year curriculum had better OSCE performance than those under the 6-year curriculum. After the clinical sub-internship training in Taipei VGH, there was no difference in the national OSCE score between the 6- and 7-year curricula. Our study suggests that clinical sub-internship is crucial for the development of clinical skills and performance in the national OSCE.

[Management of major complications in surgical treatment of mandibular osteoradionecrosis by using vascularized free flaps]

Objective: To retrospectively analyze of the prevention and management of major complications in surgical treatment of osteoradionecrosis (ORN) of the mandible by using vascularized free flaps and to provide a reference for improving clinical treatments. Methods: All cases diagnosed as mandibular ORN and received surgical treatment in the Department of Oral and Maxillofacial Surgery, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University from August 2014 to March 2019 were included. The patients' clinical data, mainly including general information, primary tumor, interval time between radiotherapy and osteoradionecrosis, surgical methods and postoperative complications, were collected. The data of surgical methods and postoperative complications of these patients were compared with the similar data of patients with malignant tumor surgically treated by using vascularized free flaps during the same period. Results: The postoperative follow-up data of 104 patients with mandibular ORN, who underwent surgery in our hospital, were collected. In the control group, surgeries of vascularized free flap transfer were performed in 430 patients with malignant tumor. Among the 34 ORN cases (34/104, 32.7%) of segmental resection with vascularized free flap transfer, there were 13 cases (13/34, 38.2%) of postoperative local infection in maxillofacial area, 6 cases (17.6%) of pulmonary infection, 2 cases (5.9%) of venous thrombosis, 3 cases (8.8%) of anastomotic artery rupture and 5 cases (14.7%) of vascular crisis. One case died of depression and misanthropy. Meanwhile, among 430 patients with malignant tumor who underwent surgeries of vascular free flap reconstruction, 25 cases (5.8%) had postoperative local infection and 29 cases (6.7%) had pulmonary infection. Vascular crisis occurred in 12 cases (2.8%) and anastomotic artery rupture in 1 case (0.2%). No venous thrombosis and misanthropy occurred. The incidence of postoperative complications in mandibular ORN was much higher than that of vascularized free flap transfer surgeries in malignant tumor cases (P<0.05). Conclusions: Compared with patients with malignant tumors undergoing vascularized free flap transfer surgeries, patients with mandibular ORN undergoing same surgeries are more likely to have postoperative complications. This study may help clinicians to fully understand the local, general and psychological conditions during the perioperative period of ORN patients.

Sustained effects of faculty leadership development modules for clinical instructors of core competences education in Taiwan: a four-year explanatory case study

BACKGROUND

The Accreditation Council for Graduate Medical Education (ACGME) core competencies (CC) in general medicine-based primary care are essential for junior medical trainees. In this country, a regular faculty development (FD) program aimed at training faculty in instructing (teaching and assessing) these CC had operated. However, leadership was not emphasized. In a new intervention module, the roles and associated responsibilities of clinical instructors to conduct, design, and lead CC-based education were emphasis.

AIMS

This follow-up explanatory case study compares the effectiveness of intervention module with that of the previous regular module.

METHODS

The regular group (n = 28) comprised clinical instructors who participated in the FD module during the 2013-2014 year while the intervention group (n = 28) was composed of 2015-2016 participants. Prior to the formal (hands-on) training, participants in the intervention group were asked to study the online materials of the regular module. These participants then received a 30-h hands-on training in conducting, designing, and leading skills. Finally, they prepared a 10-h reflective end-of-module presentation of their real-world practices.

RESULTS

Following the training, a higher degree improvement in participants self-reported familiarity with CC education, self-confidence in their ability to deliver CC education and sustained involve CC education were noted among the intervention FD group, compared with the regular FD group. In the intervention group, senior academicians (associate and full professor) are more substantially involved in designing and leading CC-based courses than junior academicians (lecturers and assistant professors). Among non-teaching award winners of in the intervention FD group, the follow-up degree of sustained involvement in delivering, designing and leading CC-based courses was significantly higher than that of the regular group.

CONCLUSIONS

Our study demonstrated that leadership training in the intervention FD modules substantially motivated clinical instructors to become leaders in CC education.

Early Signal of Emerging Nuclear Collectivity in Neutron-Rich ^{129}Sb

Radioactive ^{129}Sb, which can be treated as a proton plus semimagic ^{128}Sn core within the particle-core coupling scheme, was studied by Coulomb excitation. Reduced electric quadrupole transition probabilities, B(E2), for the 2^{+}⊗πg_{7/2} multiplet members and candidate πd_{5/2} state were measured. The results indicate that the total electric quadrupole strength of ^{129}Sb is a factor of 1.39(11) larger than the ^{128}Sn core, which is in stark contrast to the expectations of the empirically successful particle-core coupling scheme. Shell-model calculations performed with two different sets of nucleon-nucleon interactions suggest that this enhanced collectivity is due to constructive quadrupole coherence in the wave functions stemming from the proton-neutron residual interactions, where adding one nucleon to a core near a double-shell closure can have a pronounced effect. The enhanced electric quadrupole strength is an early signal of the emerging nuclear collectivity that becomes dominant away from the shell closure.

Creation of nurse-specific integrated interprofessional collaboration and team-efficiency scenario/video improves trainees' attitudes and performances

BACKGROUND

It is importance to train the interprofessional collaboration (IPC) and team-efficiency (TE) of medical trainees. This prospective study evaluates whether implementation of scenario/video-created workshops in integrated IPC and TE (IIT) program provides additional benefits for IPC-TE skills of nursing trainees.

METHODS

Mock simulation with two IIT scenarios was held as preintervention IPC-TE assessment. Basic and advanced workshops were arranged for teams of intervention groups for creation of discipline-specific scenario and video. Thirty-six nursing trainees were randomized into teams of five members (three nursing students, one standardized medical student, and one standardized trainees of other profession) in either intervention (scenario plus video and scenario) or control groups. After intervention, all groups received the formal simulation-based assessment using another two IIT scenario. In addition to instructors-based assessment of team' performance in mock and formal IIT simulation using interprofessional team collaboration scale (AITCS), self-assessment of attitudes and program-value score were completed by each trainee, using attitudes toward interprofessional health care teams scale (ATIHCTS) at all stages.

RESULTS

Nursing trainees in intervention group gave high satisfaction score to this IIT intervention. In comparison with control group, greater increase in instructor-assessed team performance in the "partnership," "cooperation," and "shared decision making" domains of AITCS and the self-assessed "quality of care delivery" and TE domains of ATIHCTS were noted in the intervention groups. The overall improvement was greater in the scenario plus video group than those in the scenario group. Further, these improvements among nursing trainees persisted until follow-up stage at 4-weeks later.

CONCLUSION

For nursing trainees, our study suggested that implementation of a scenario creation-based training resulted in additional improvement in trainee' IPC and TE behaviors and attitudes. Additionally, making video of newly created nurse-specific scenario enhances partnership and cooperation among nursing trainees and their interprofessional team members.

Mixed simulation course increases participants' positive stress coping abilities

BACKGROUND

Lack of health professional awareness of interprofessional collaborative practice (IPCP) often results in stress and conflicts between team members in the medical system. Our study aimed to compare the effectiveness of mixed simulation-interprofessional education (IPE) courses to enhance coping strategies for IPCP-associated stress.

METHODS

Participants (n = 54) from the disciplines of physicians (n = 12), nurses (n = 28) and pharmacists (n = 14) were enrolled. Over the course of the study period, all participants were asked to complete pre-course (T1), post-course (T2) and end-of-study (T3) questionnaires for self-assessment of perceived stress scale (PSS), stress coping preference scale (SCPS), and IPCP proficiency.

RESULTS

Basically, physicians felt less IPCP-associated stress than did nurses and pharmacists. For physicians, nurses and pharmacists, the mean post-course (T2) PSS scores were significantly lower than pre-course (T1) PSS scores, which indicated decreased IPCP-associated stress after mixed simulation-IPE courses. In comparison with physicians, the greater difference (T2-T1 scores) in the PSS and positive coping SCPS subscales scores were noted among nurses and pharmacists. For nurses and pharmacists, the further improvements in stress coping abilities (PSS scale and positive SCPS subscale) were noted at the end-of-study self-assessment by comparison of post-course scores with end-of-study scores. For IPCP proficiency, all participants gave more positive responses to the specific questions in the end-of-study questionnaires.

CONCLUSION

Our study supports the use of mixed simulation-IPE courses as part of continuing education to enhance positive stress coping strategies.

Simulation-based inter-professional education to improve attitudes towards collaborative practice: a prospective comparative pilot study in a Chinese medical centre

OBJECTIVES

Inter-professional education (IPE) builds inter-professional collaboration (IPC) attitude/skills of health professionals. This interventional IPE programme evaluates whether benchmarking sharing can successfully cultivate seed instructors responsible for improving their team members' IPC attitudes.

DESIGN

Prospective, pre-post comparative cross-sectional pilot study.

SETTING/PARTICIPANTS

Thirty four physicians, 30 nurses and 24 pharmacists, who volunteered to be trained as seed instructors participated in 3.5-hour preparation and 3.5-hour simulation courses. Then, participants (n=88) drew lots to decide 44 presenters, half of each profession, who needed to prepare IPC benchmarking and formed Group 1. The remaining participants formed Group 2 (regular). Facilitators rated the Group 1 participants' degree of appropriate transfer and sustainable practice of the learnt IPC skills in the workplace according to successful IPC examples in their benchmarking sharing.

RESULTS

For the three professions, improvement in IPC attitude was identified by sequential increase in the post-course (second month, T₂) and end-of-study (third month, T₃) Interdisciplinary Education Perception Scale (IEPS) and Attitudes Towards Healthcare Teams Scale (ATHCTS) scores, compared with pre-course (first month, T₁) scores. By IEPS and ATHCTS-based assessment, the degree of sequential improvements in IPC attitude was found to be higher among nurses and pharmacists than in physicians. In benchmarking sharing, the facilitators' agreement about the degree of participants'appropriate transfer and sustainable practice learnt 'communication and teamwork' skills in the workplace were significantly higher among pharmacists and nurses than among physicians. The post-intervention random sampling survey (sixth month, T_post) found that the IPC attitude of the three professions improved after on-site IPC skill promotion by new programme-trained seed instructors within teams.

CONCLUSIONS

Addition of benchmark sharing to a diamond-based IPE simulation programme enhances participants' IPC attitudes, self-reflection, workplace transfer and practice of the learnt skills. Furthermore, IPC promotion within teams by newly trained seed instructors improved the IPC attitudes across all three professions.

Effects of a new parallel primary healthcare centre and on-campus training programme on history taking, physical examination skills and medical students' preparedness: a prospective comparative study in Taiwan

OBJECTIVES

The primary healthcarecentre (PHCC) is the first place that medical students experience patient contact. Usually, medical students are frustrated by a lack of proper skills training for on-campus history taking (HT), physical examination (PE) and self-directed learning (SDL) to prepare for their PHCC and inhospital patient contact. For pre-clerks, this study aims to compare the effectiveness of PHCC training and PHCC training in combination with on-campus HT and PE training modules (PHCC+on-campus) on their clerkship preparedness.

DESIGN

This comparative study utilised prospective, consecutive, end of pre-clerkship group objective structured clinical examination (GOSCE), beginning of clerkship OSCE and self-administered Preparation for Hospital Practice Questionnaire (PHPQ).

SETTING/PARTICIPANTS

128 pre-clinical clerk volunteers (64 each year) receiving PHCC training (7 week PHCCtraining in addition to 7 week assignment based group learning, academic year 2014, controls) and PHCC training in combination with on-campus module training (academic year 2015, 7 week PHCCtraining in addition to 7 week on-campus sessions) were sequentially assessed before the module (week 1), at the end of the module (week 14) and at the beginning of clerkship (week 25).

RESULTS

For overall HT and PE skills, both PHCC and PHCC+on-campus module trained pre-clerks performed better on OSCE than GOSCE. Additionally, the improvement was accompanied by higher self-reported PHPQ scores in 'confidence/coping' and 'SDL' domains. At the end of the pre-clerkship and the beginning of the clerkship stages, the degree of improvement in preparedness in 'confidence/coping' and 'SDL' domains was higher for those in the PHCC+on-campus group than for those in the PHCC group. Among the PHCC+on-campus module participants, a positive association was observed between high mean PHPQ-SDL scores and high OSCE scores.

CONCLUSIONS

Our study suggests that the PHCC+on-campus module, which is paired faculty led and pre-trained dyad student assisted, is effective in developing a preclinical clerk's HT and PE skills and intensifying SDL/patient management abilities to prepare for hospital practice in clerkship.

Voluntary attendance of small-group brainstorming tutoring courses intensify new clerk's "excellence in clinical care": a pilot study

BACKGROUND

Clerkship provides a unique way of transferring the knowledge and skills gathered during medical school's curriculum into real-ward clinical care environment. The annual program evaluation has indicated that the training of clerks in diagnostic and clinical reasoning skills needed to be enhanced. Recently, "clinical excellence" program have been promoted in our institution to augment the excellence in clinical care of new clerks. Current study aims to evaluate whether this pilot program improve the "clinical excellence" of new clerks.

METHODS

In a pilot study, groups of new clerks in years 2013 and 2014 voluntarily attended either a small-group brainstorming course or a didactic classroom tutoring courses as part of their 3-month internal medicine clinical rotation block. A third group of new clerks did not join either of the above courses and this group served as the control group. Pre-block/post-block self-assessment and post-block 5-station mini-Objective Subjective Clinical Examinations (OSCEs) were used to evaluate the effectiveness of these two additional courses that trained diagnostic and clinical reasoning skills.

RESULTS

Overtime, the percentages of new clerks that attended voluntarily either the small-group brainstorming or classroom tutoring courses were increased. Higher post-block self-assessed diagnostic and clinical reasoning skill scores were found among individuals who attended the small-group brainstorming courses compared to either the didactic group or the control group. In a corresponding manner, the small-group brainstorming group obtained higher summary OSCE_diag and OSCE_reason scores than either the didactic group or control group. For all basic images/laboratory OSCE stations, the individual diagnostic skill (OSCE_diag) scores of the small-group brainstorming group were higher than those of the didactic group. By way of contrast, only the clinical reasoning skill (OSCE_reason) scores of the basic electrocardiogram and complete blood count + biochemistry OSCE station of thesmall-group brainstorming group were higher than those of the didactic group. Among the small-group brainstorming group, clerks with higher cumulative learning hours (>30-h) had significant higher OSCE_diag and OSCE_reason scores (>400) than those with less cumulative learning hours.

CONCLUSION

Our pilot study provides a successful example of the use of a small-group tutoring courses for augmenting the diagnostic and clinical reasoning skills of new clerks. The positive results obtained during the initial 2-year long pilot "clinical excellence" program have encouraged the formal implementation of this course as part of the clerkship curriculum.

A model of four hierarchical levels to train Chinese residents' teaching skills for "practice-based learning and improvement" competency

OBJECTIVES

The current study focused on validating a protocol for training and auditing the resident's practice-based learning and improvement (PBLI) and quality improvement (QI) competencies for primary care.

METHODS

Twelve second-year (R2), 12 first-year (R1) and 12 postgraduate year-1 residents were enrolled into group A, B and C, respectively, as trainees. After three training protocols had been completed, a writing test, self-assessed questionnaire and mini-OSTE and end-of-rotation assessment were used in auditing the PBLI competency, performance and teaching ability of trainees.

RESULTS

Baseline expert-assessed PBLI and QI knowledge application tool writing scores were low for the R1 and R2 residents. After three training protocols, PBLI and QI proficiencies, performance and teaching abilities were improved to similar levels cross the three training levels of residents based on the expert-assessed writing test-audited assessments and on the faculty and standardized clerk-assessed end-of-rotation-/mini-OSTE-audited assessments.

CONCLUSION

The different four-level hierarchical protocols used to teach group A, B and C were equally beneficial and fitted their needs; namely the different levels of the trainees. Specifically, each level was able to augment their PBLI and QI proficiency. This educational intervention helps medical institutions to train residents as PBLI instructors.

Constraint of the astrophysical ^{26g}Al(p,γ)^{27}Si destruction rate at stellar temperatures

The Galactic 1.809-MeV γ-ray signature from the β decay of ^{26g}Al is a dominant target of γ-ray astronomy, of which a significant component is understood to originate from massive stars. The ^{26g}Al(p,γ)^{27}Si reaction is a major destruction pathway for ^{26g}Al at stellar temperatures, but the reaction rate is poorly constrained due to uncertainties in the strengths of low-lying resonances in ^{27}Si. The ^{26g}Al(d,p)^{27}Al reaction has been employed in inverse kinematics to determine the spectroscopic factors, and hence resonance strengths, of proton resonances in ^{27}Si via mirror symmetry. The strength of the 127-keV resonance is found to be a factor of 4 higher than the previously adopted upper limit, and the upper limit for the 68-keV resonance has been reduced by an order of magnitude, considerably constraining the ^{26g}Al destruction rate at stellar temperatures.

Seasonal variation and source apportionment of organic tracers in PM10 in Chengdu, China

Organic compound tracers including n-alkanes, triterpane, sterane, polycyclic aromatic hydrocarbons (PAHs) and dicarboxylic acids of airborne particulate matter (PM10) were characterized for samples collected at five sites from July 2010 to March 2011 using GC/MS. Spatial and temporal variations of these organic tracers in PM10 were studied, and their sources were then identified respectively. Average daily concentrations of PM10 varied in different seasons with the trend of PM10 in winter (0.133 mg/m(3)) > autumn (0.120 mg/m(3)) > spring (0.103 mg/m(3)) > summer (0.098 mg/m(3)). Daily concentrations of n-alkanes (C11-C36) ranged from 12.11 to 163.58 ng/m(3) with a mean of 61.99 ng/m(3). The C max and CPI index of n-alkanes indicated that vehicle emissions were the major source in winter, while the contributions of high plant wax emissions became significant in other seasons. It was discovered that the main sources of triterpenoid and steranes were gasoline and diesel engine emissions. Concentrations of ∑15PAHs in PM10 also varied (12.25-58.56 ng/m(3)) in different seasons, and chrysene, benzo(a)pyrene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(ghi) perylene and fluoranthene were the dominant components. In the four seasons, the concentration of ∑15PAHs was relatively higher at the northern site because of traffic congestion. The main source of airborne PAHs was traffic emissions and coal combustion. Average daily concentrations of dicarboxylic acids (C4-C10) in PM10 ranged from 12.11 to 163.58 ng/m(3), of which azeleic acid was the major compound (0.49-52.04 ng/m(3), average 14.93 ng/m(3)), followed by succinic acid (0.56-19.08 ng/m(3), average 6.84 ng/m(3)). The ratio of C6/C9 showed that the major source in winter was biological, while the contributions of emissions from anthropogenic activities were much higher in summer.

Increased myo-inositol level in dorsolateral prefrontal cortex in migraine patients with major depression

Background

Although the comorbidity between migraine and major depressive disorder (MDD) has been recognized, the pathophysiology remains unclear. The dorsolateral prefrontal cortex (DLPFC) is a well-known neural substrate for MDD. We investigated the relationship between brain metabolites in DLPFC and comorbid MDD in migraine patients.

Methods

We recruited migraine patients from a tertiary headache clinic. A board-certified psychiatrist conducted a structured interview for MDD diagnosis. The severity of depression was evaluated by the Beck Depression Inventory (BDI). Thirty migraine patients (five men, 25 women; mean age: 40.4 ± 12.4 years) completed the study, and 16 of them were diagnosed with MDD. All patients underwent a magnetic resonance spectroscopy (MRS) examination focusing on bilateral DLPFC. The ratios of N-acetylaspartate (NAA), choline (Cho), and myo-inositol (mI) to total creatine (tCr) were compared between migraine patients with and without MDD, and were correlated with BDI scores.

Results

Relative to patients without MDD, migraine patients with MDD had higher mI/tCr ratios in the bilateral DLPFC ( p = 0.02, left; p = 0.02, right, Mann-Whitney U test). The mI/tCr ratios in the right DLPFC were positively correlated with BDI scores ( r = 0.52, p = 0.003). The NAA/tCr and Cho/tCr ratios did not differ between migraine patients with and without MDD.

Conclusion

Increased mI/tCr within the DLPFC might be associated with the presence of MDD in migraine patients.

Hypnic headache: A review of clinical features, therapeutic options and outcomes

Background

Hypnic headache (HH), first reported in 1988, is a rare sleep-related headache disorder. In 2013 a new diagnostic criteria was proposed for HH in the International Classification of Headache Disorders, the third version beta (ICHD-3β).

Purpose

This review aimed to update the clinical characteristics, therapeutic options and clinical outcomes in patients with HH and also validate the new diagnostic criteria.

Methods

Based on a literature search in the major medical databases, we analyzed all case reports or case series on HH that have been published since the first description by Raskin. Except for symptomatic patients, all reported patients were included regardless of which diagnostic criteria were adopted. Four studies that reported the field-testing results of the ICHD-2 criteria were selected to validate the new ICHD-3β criteria.

Results

In total, 250 adult and five childhood patients are described in this review. The majority of patients were elderly and their ages of onset were typically more than 50 years old (92%). Approximately 7.7% of patients had some trigeminal autonomic features, which are not permitted in the ICHD-3β criteria. Compared with the ICHD-2 criteria, the diagnostic rate under the new criteria increased from 65% to 85% in recently reported cases. Randomized control trials both for acute and prophylactic treatment are lacking. Based on observational studies, the most effective acute treatment is caffeine and prophylactic medications in use are lithium, caffeine and indomethacin. Without treatment, the disease course is usually protracted but spontaneous remission did occur in 12 patients (4.8%). In those treated with prophylactic agents, no recurrence was noted in 43% of patients, even following withdrawal of medication.

Conclusions

The new ICHD-3β criteria are more sensitive and exhaustive for HH than the ICHD-2 criteria. Prophylactic treatment provides better outcomes; however, randomized controlled studies for treatment are needed to further verify the efficacy of the different drugs.

Proton pump inhibitor-related headaches: A nationwide population-based case-crossover study in Taiwan

Background

Headaches resulting from proton pump inhibitor (PPI) use could cause discontinuation of PPI in as many as 40% of patients who experience such headaches. Previous studies focusing on acute headache risk from PPI use are rare and limited to clinical trials of a single PPI.

Objectives

To investigate the association between PPI use and headache with a nationwide population-based case-crossover study.

Methods

Records containing the first diagnosis of any headache, including migraine and tension-type headaches, were retrieved from Taiwan National Health Insurance Database (1998–2010). We compared the rates of PPI use for cases and controls during time windows of 7, 14, and 28 days. The adjusted self-matched odds ratios (ORs) and 95% confidence intervals (CIs) from a conditional logistic regression model were used to determine the association between PPI use and headache.

Results

Overall, 314,210 patients with an initial diagnosis of any headache during the study period were enrolled. The adjusted ORs for headache risk after PPI exposure were calculated for three time periods (within 7 days = 1.41, p = 0.002, 95% CI 1.14–1.74; within 14 days = 1.36, p < 0.001, 95% CI 1.16–1.59; within 28 days = 1.20, p = 0.002, 95% CI 1.07–1.35). Subgroup analyses showed female patients had an increased risk of headache. Among PPIs, lansoprazole and esomeprazole had the highest risks of headache incidence, which were similar to that of nitrates.

Conclusion

PPI usage is associated with an increased risk for acute headache. Female patients and use of lansoprazole or esomeprazole present the greatest risks of headache.

Double-magic nature of 132Sn and 208Pb through lifetime and cross-section measurements

Single-neutron states in (133)Sn and (209)Pb, which are analogous to single-electron states outside of closed atomic shells in alkali metals, were populated by the ((9)Be, (8)Be) one-neutron transfer reaction in inverse kinematics using particle-γ coincidence spectroscopy. In addition, the s(1/2) single-neutron hole-state candidate in (131)Sn was populated by ((9)Be, (10)Be). Doubly closed-shell (132)Sn (radioactive) and (208)Pb (stable) beams were used at sub-Coulomb barrier energies of 3 MeV per nucleon. Level energies, γ-ray transitions, absolute cross sections, spectroscopic factors, asymptotic normalization coefficients, and excited-state lifetimes are reported and compared with shell-model expectations. The results include a new transition and precise level energy for the 3p(1/2) candidate in (133)Sn, new absolute cross sections for the 1h(9/2) candidate in (133)Sn and 3s(1/2) candidate in (131)Sn, and new lifetimes for excited states in (133)Sn and (209)Pb. This is the first report on excited-state lifetimes of (133)Sn, which allow for a unique test of the nuclear shell model and (132)Sn double-shell closure.

Cluster headache is associated with an increased risk of depression: A nationwide population-based cohort study

Objective

To investigate whether cluster headache (CH) was a risk factor for depression in a nationwide population-based follow-up study.

Background

There are few studies about the relationship between CH and depression, and prior research has been limited by cross-sectional studies or small sample sizes.

Methods

We identified 673 CH patients from the Taiwan National Health Insurance database between 2005 and 2009. The two comparison cohorts included age-, sex- and Charlson’s score-matched migraine patients ( n = 2692) and controls (patients free from migraine or CH, n = 2692). The cumulative incidence of depression was compared among these three cohorts until the end of 2009. We also calculated predictors of depression in the CH cohort.

Results

After the median 2.5-year follow-up duration, the CH cohort had a greater risk for developing depression compared to the control cohort (adjusted hazard ratio; aHR = 5.6, 95% CI 3.0–10.6, p < 0.001) but not the migraine cohort (aHR = 1.1, 95% CI 0.7–1.7, p = 0.77). Of the CH patients, the number of cluster bout periods per year was a risk factor for depression (aHR = 3.8, 95% CI 2.6–5.4, p < 0.001).

Conclusion

Our results showed that CH is associated with an increased risk for depression. The strength of this association is similar to that of migraine.

Neutron single particle structure in 131Sn and direct neutron capture cross sections

Recent calculations suggest that the rate of neutron capture by (130)Sn has a significant impact on late-time nucleosynthesis in the r process. Direct capture into low-lying bound states is expected to be significant in neutron capture near the N=82 closed shell, so r-process reaction rates may be strongly impacted by the properties of neutron single particle states in this region. In order to investigate these properties, the (d,p) reaction has been studied in inverse kinematics using a 630 MeV beam of (130)Sn (4.8 MeV/u) and a (CD(2))(n) target. An array of Si strip detectors, including the Silicon Detector Array and an early implementation of the Oak Ridge Rutgers University Barrel Array, was used to detect reaction products. Results for the (130)Sn(d, p)(131)Sn reaction are found to be very similar to those from the previously reported (132)Sn(d, p)(133)Sn reaction. Direct-semidirect (n,γ) cross section calculations, based for the first time on experimental data, are presented. The uncertainties in these cross sections are thus reduced by orders of magnitude from previous estimates.

Halo nucleus 11Be: a spectroscopic study via neutron transfer

The best examples of halo nuclei, exotic systems with a diffuse nuclear cloud surrounding a tightly bound core, are found in the light, neutron-rich region, where the halo neutrons experience only weak binding and a weak, or no, potential barrier. Modern direct-reaction measurement techniques provide powerful probes of the structure of exotic nuclei. Despite more than four decades of these studies on the benchmark one-neutron halo nucleus 11Be, the spectroscopic factors for the two bound states remain poorly constrained. In the present work, the 10Be(d,​p) reaction has been used in inverse kinematics at four beam energies to study the structure of 11Be. The spectroscopic factors extracted using the adiabatic model were found to be consistent across the four measurements and were largely insensitive to the optical potential used. The extracted spectroscopic factor for a neutron in an nℓj=2s(1/2) state coupled to the ground state of 10Be is 0.71(5). For the first excited state at 0.32 MeV, a spectroscopic factor of 0.62(4) is found for the halo neutron in a 1p(1/2) state.

Near-barrier fusion of Sn + Ni and Te + Ni systems: examining the correlation between nucleon transfer and fusion enhancement

The fusion excitation functions for radioactive (132)Sn + (58)Ni and stable (130)Te + (58,64)Ni were measured at energies near the Coulomb barrier. The coupling of transfer channels in heavy-ion fusion was examined through a comparison of Sn + Ni and Te + Ni systems, which have large variations in the number of positive Q-value nucleon transfer channels. In contrast with previous experimental comparisons, where increased sub-barrier fusion cross sections were observed in systems with positive Q-value neutron transfer channels, the reduced excitation functions were equivalent for the different Sn + Ni and Te + Ni systems. The present results suggest a dramatically different influence of positive Q-value transfer channels on the fusion process for the Sn + Ni and Te + Ni systems.

Bilateral hippocampal abnormalities on diffusion-weighted MRI in transient global amnesia: report of a case

The pathophysiology of transient global amnesia (TGA) is still speculative. Recently, diffusion-weighted image (DWI) of magnetic resonance imaging (MRI) documented tiny lesions in the hippocampus of patients with TGA in the acute stage. Most studies reported unilateral lesions on MRI. We present one patient of TGA with high signal-intensity lesions in bilateral hippocampus on DWI at the acute stage. The serial findings of brain MRI support the ischemic nature of TGA. Related mechanism about TGA is discussed.

Improved gene expression using low molecular weight peptides produced from protamine sulfate

DNA condensation plays a key role in non-viral gene delivery by affecting gene transfection, nuclear targeting, and eventual gene expression efficiency. Theoretically, a DNA condenser with the appropriate DNA condensation ability but without affecting DNA dissociation from DNA condensates inside the cytoplasm should be a perfect carrier for gene delivery. Protamine is a natural DNA condensation agent and has been widely used in gene delivery. In this work, protamine was selectively digested enzymatically to produce low molecular weight protamine fragments (LMWPs) of various lengths and amino acid compositions. The DNA condensation ability and gene transfection efficiency of these LMWP peptides were tested. Compared to protamine, all the LMWP peptides showed lower DNA binding strength. However, some LMWP peptides demonstrated excellent DNA condensation ability and could form very compact DNA condensates with small particle size (approximately 100 nm). More interestingly, LMWP peptide-mediated in vitro gene delivery showed prolonged (up to 12 days) gene expression. Results from this study suggest that designing DNA condensers with appropriate and tunable DNA binding strengths and condensation abilities would be an effective means to improve gene expression and thus gene therapy efficiency. Since LMWP peptides have low immunogenicity, they would be safer than protamine for use in gene therapies.

Enhanced fusion-evaporation cross sections in neutron-rich 132Sn on 64Ni

Evaporation residue cross sections have been measured with neutron-rich radioactive 132Sn beams on 64Ni in the vicinity of the Coulomb barrier. The average beam intensity was 2 x 10(4) particles per second and the smallest cross section measured was less than 5 mb. Large sub-barrier fusion enhancement was observed. Coupled-channel calculations taking into account inelastic excitation significantly underpredict the measured cross sections below the barrier. The presence of several neutron transfer channels with large positive Q values suggests that multinucleon transfer may play an important role in enhancing the fusion of 132Sn and 64Ni.

A less toxic heparin antagonist--low molecular weight protamine

A new thirteen amino acid peptide, named low molecular weight protamine (LMWP), was obtained through the enzymatic digestion of native protamine. Both in vitro and in vivo results showed that LMWP fully maintained the heparin neutralization function of protamine but had much lower immunogenicity and antigenicity. Unlike protamine, neither LMWP nor LMWP/heparin complexes caused significant blood platelet aggregation in rats. These results suggest that LMWP can be used as a substitute for protamine for developing a new generation of nontoxic heparin antagonists.

ATTEMPTS: a heparin/protamine-based delivery system for enzyme drugs

A prodrug delivery system termed "Antibody Targeted, Triggered, Electrically Modified Prodrug-Type Strategy (ATTEMPTS)" has been developed to permit the antibody-directed administration of inactive enzyme drug including tissue-type plasminogen activator (tPA), and allow a subsequent triggered release of the active tPA at the target site. Cation-modified tPA (mtPA) was attached to a heparin-antifibrin complex via ionic interaction, and the active tPA can subsequently be released by the addition of protamine, a competitive heparin inhibitor. Anti-fibrin IgG was conjugated to heparin via an end-point attachment to form the heparin-antifibrin complex which provides the targeting efficiency of the final heparin/mtPA complex. Cation modification was performed by either chemical conjugation by linking (Arg)7Cys to tPA with N-succinimidy-3-(2-pyridyldithio) propionate or by recombinant DNA methods. Results show that the modification process did not significantly alter the specific activity of tPA with regard to plasminogen activation, fibrin-binding ability, and response toward fibrinogen. The complexes of both modified tPA-heparin did not yield any intrinsic catalytic activity owing to the blockage of the active site of tPA by the attached heparin. On the other hand, heparin-induced inhibition of modified tPA activity was reversed by adding protamine, which is similar to that of a prodrug delivery system. These results suggest that heparin/protamine-based enzyme delivery systems may be a useful tool to improve current enzyme therapeutic status, as well as thrombolytic therapy, by both regulating the release of active enzyme and aborting the associated systemic toxic effect. Currently, modification of enzyme drugs has been optimized by recombinant DNA technology assisted by computer simulation. In addition, the original strategy has been revised to obtain enhanced therapeutic efficacy.

ATTEMPTS: a heparin/protamine-based prodrug approach for delivery of thrombolytic drugs

The aim of this study is to develop a heparin/protamine-based prodrug system for the controlled delivery of enzyme such as tissue-type plasminogen activator (tPA). This approach, termed antibody targeted, triggered, electrically modified prodrug-type strategy (ATTEMPTS), would permit antibody-directed administration of inactive tPA, and allow a subsequent triggered release of the active tPA at the target site. Cation-modified tPA (mtPA) was attached to a heparin--antifibrin complex via ionic interaction. The active tPA can be subsequently released by the addition of protamine, a competitive heparin inhibitor. Anti-fibrin IgG was conjugated to heparin via an end-point attachment to form the heparin--antifibrin--complex which provides the targeting efficiency of the final heparin--mtPA complex. Cation-modification was performed either by chemical conjugation by linking (Arg)(7)Cys to tPA with N-succinimidy-3-(2-pyridyldithio) propionate or by recombinant DNA method. Results show that the chemical modification process did not significantly alter specific activity of tPA with regard to plasminogen activation, fibrin-binding ability, and response toward fibrinogen. Expressed modified tPA (EmtPA) produced by recombinant DNA methods retained the same catalytic activity of the parent tPA, as well as a dynamic catalytic behavior depending upon the presence of heparin and protamine. Both types of modified tPA, especially the mtPA demonstrated a significantly higher affinity toward heparin or heparin--antifibrin complex than native tPA. In addition, the complexes of mtPA--heparin did not yield any intrinsic clot lysis activity owing to the blockage of the active site of tPA by attached heparin. On the other hand, heparin-induced inhibition of both mtPA and EmtPA activity was reversed by adding protamine, as confirmed by chromogenic and in vitro clot lysis assays. These results suggested that a heparin/protamine-based tPA delivery system may be a useful tool to improve current thrombolytic therapeutic status, by both precisely regulating the release of active tPA and aborting the associated bleeding risk. Alternatively, this ATTEMPTS approach could also be used to deliver enzyme drugs while diminishing their associated toxic effects.

Decay of a Resonance in 18Ne by the Simultaneous Emission of Two Protons

Radioactive ion beams of 17F were used to study several resonance states in 18Ne. Clear evidence for simultaneous two-proton emission from the 6.15 MeV state (Jpi = 1(-)) in 18Ne has been observed with the reaction 17F+1H. Because of limited angular coverage, the data did not differentiate between the two possible mechanisms of simultaneous decay, diproton (2He) emission or direct three-body decay. The two-proton partial width was found to be 21+/-3 eV assuming 2He emission and 57+/-6 eV assuming three-body decay. The total width of the 1(-) state was measured to be 50+/-5 keV. Several additional resonances that decay by single proton emission were also studied.

Titration study of MUSE (Medicated Urethral System for Erection) in erectile dysfunction

PURPOSE

We assessed the erectile responses and adverse reactions to prostaglandin E1 delivered via the medicated urethral system for erection (MUSE) in a titration study to determine optimal dose.

METHODS

Sixty-four patients with erectile dysfunction underwent in-office testing with MUSE to determine erectile response. Following thorough instructions, patients were taught how to use MUSE themselves. The titration study started with a dose of 125 micrograms, and increased to 250 micrograms, 500 micrograms, and finally 1,000 micrograms. In patients who had an erectile response, erection scoring, color duplex Doppler study, blood pressure monitoring, recording of subjective complaints, and repeated laboratory examinations were performed to evaluate the positive and adverse effects of MUSE.

RESULTS

Forty-three of the 64 patients achieved a maximal erection with MUSE, as shown by systolic peak flow velocities in the deep penile arteries of greater than 27 cm/s on Doppler ultrasonography. One patient was unsatisfied with his erectile response and dropped out of the study. Of the 42 patients who completed the study, most (35) were satisfied with the response achieved at the higher doses of 500 micrograms and 1,000 micrograms. A modified soft rubber band was needed to achieve a satisfactory erectile response in 18 patients. Only four patients experienced serious urethral burning during MUSE application.

CONCLUSIONS

MUSE was effective and safe in most patients with erectile dysfunction in this study. For patients not satisfied with the extent of penile rigidity achieved with MUSE, the use of a modified soft rubber band for erectile assistance, as well as a program for improved patient education, may help to achieve a better erectile response and facilitate compliance with treatment regimens at home.

A prodrug approach for delivery of t-PA: construction of the cationic t-PA prodrug by a recombinant method and preliminary in vitro evaluation of the construct

Previously, we reported a novel prodrug approach, that could lead to targeted thrombolysis without the risk of bleeding. The approach consists of a protein conjugate made of two components: a fibrin targeting antibody (Ab) linked to an anionic heparin, and a plasminogen activator (PA) derivatized with cationic species. These two components are linked by means of an electrostatic interaction. Because the cationic species are small, the modified PA would retain its thrombolytic activity. However, this activity would be inhibited after binding to the counterpart due to the blockage of the PA active site by the appended macromolecules. Because protamine is a clinical antagonist to heparin, it can be used in humans to dissociate the modified PA from its counterpart. Thus, the approach would permit the administration of a fibrin targeting but inactive thrombolytic drug (thereby alleviating the bleeding risk by avoiding systemic generation of plasmin), and subsequently a triggered release of the active drug to the fibrin deposit. In our previous work, we demonstrated the feasibility of the approach by producing a positively charged PA by means of chemical conjugation of a cationic CRRRRRRR peptide with urokinase. In this study, we further extended our work and produced a similar cationic t-PA by means of a recombinant DNA approach; i.e., by fusion of a poly(Arg)7 peptide to the kringle-1 domain of t-PA. Results obtained from the restriction enzyme analysis and the Western blot yielded full identification of this recombinant protein. This recombinant poly(Arg)7-modified-t-PA protein conjugate (termed "rmt-PA" hereafter) completely retained the fibrinolytic activity of the original recombinant, unmodified t-PA (termed "rt-PA" hereafter), as measured by the chromogenic assay and fibrin agar lysis assay. The prodrug and triggered release features of the proposed approach were confirmed by partial inhibition of the plasminogen activating activity of this protein by heparin, and the partial reversal of such inhibition by protamine.

Biomedical application of immobilized enzymes

Reports on chemical immobilization of proteins and enzymes first appeared in the 1960s. Since then, immobilized proteins and enzymes have been widely used in the processing of variety of products and increasingly used in the field of medicine. Here, we present a review of recent developments in immobilized enzyme use in medicine. Generally speaking, the use of immobilized enzyme in medicine can be divided into two major categories: biosensors and bioreactors. A brief overview of the evolution of the biosensor and bioreactor technology, of currently existing applications of immobilized enzymes, of problems that researchers encountered, and of possible future developments will be presented.

A novel approach for delivery of enzyme drugs: preliminary demonstration of feasibility and utility in vitro

A novel heparin/protamine-based approach for delivery of enzyme drugs without associated toxic effects has been proposed. This approach would allow an enzyme drug to be administered in an inactive (i.e. pro-drug) form and then released at the target site in an active form using protamine as the triggering agent. The pro-drug and the triggered release features of this approach would permit the enzyme drug to act specifically and only on its target substrates while sparing normal substrates, thereby alleviating unwanted toxic effects. The in vitro feasibility of the approach has been successfully demonstrated using trypsin as the model protease drug. In addition, the utility of the approach has also been demonstrated by applying the system in delivering streptokinase, one of the most widely used clinical drugs in thrombolytic therapy. This approach may open up the possibility of developing a wide range of new catalytic drugs that are initially thought to be impossible for therapeutic use due to their potent toxic effects.

A novel heparin/protamine-based pro-drug type delivery system for protease drugs

Previously we proposed a heparin/protamine-based system for delivery of protease drugs such as tissue-specific plasminogen activator (tPA). To demonstrate the feasibility of this approach as well as its pro-drug and triggered release features, positively charged peptides [(Arg)(7)Cys] were successfully linked to tissue-specific plasminogen activator (tPA) using the crosslinking agent N-succinimidyl-3-(2-pyridyldithio)- propionate. This cation-modified tPA showed much stronger heparin affinity than the parent tPA. The complex formed by mtPA and heparin was stable in human plasma, and the activity of mtPA in such a complex was inhibited by the appended heparin. Similarly, the activity of mtPA could also be inhibited by a heparin-antifibrin IgG conjugate in which heparin was linked, via endpoint attachment, to the sugar moieties in the F(c) region of anti-fibrin IgG. Aside from this pro-drug feature exhibited by the binding of the macromolecule heparin to mtPA, results from chromogenic and in vitro clot lysis assay demonstrated that the heparin-induced inhibition of the mtPA activity could be easily reversed by the addition of an adequate amount of protamine. These findings suggest the applicability of the heparin/protamine delivery system to abort the potential bleeding risks associated with clinical use of tPA. In addition to the chemical conjugation method, modified tPA could also be produced by the recombinant DNA method. The expressed modified tPA (EmtPA) thus prepared retained the full catalytic activity of the parent tPA, and this activity could also be inhibited by heparin, and the heparin-induced inhibition could be reversed following the addition of protamine.

The potential mechanism for the effect of heparin on tissue plasminogen activator-mediated plasminogen activation

The effects and possible role of heparin on tissue plasminogen activator-mediated plasminogen activation was thoroughly investigated. Direct analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated that heparin increased the conversion of plasminogen to plasmin. Experiments by fluorescence quenching suggested that the stimulation of tissue plasminogen activator activity probably was due to a direct binding of heparin to tissue plasminogen activator, causing a conformational change of tissue plasminogen activator and rendering it more accessible to plasminogen interaction. The absence of additive stimulation effects on tissue plasminogen activator-mediated plasminogen activation when both heparin and fibrinogen were present also implied that both compounds interacted with tissue plasminogen activator via the same domain; it appeared to be most likely via the kringle-2 domain in tissue plasminogen activator based on studies using epsilon-aminocaproic acid as an inhibitor. Unlike heparin-induced stimulation of antithrombin-thrombin interaction, the heparin-induced stimulation of tissue plasminogen activator did not seem to follow a template model. Only in the presence of a high plasminogen or a low tissue plasminogen activator concentration, massive stimulation of tissue plasminogen activator activity was observed via a pseudotemplate model. The results suggest that precautions concerning high heparin dose should be given during its conjunctive clinical use with tissue plasminogen activator in thrombolytic therapy to reduce the risk of hemorrhage.

Inhibition of nitric oxide synthesis in primary cultured mouse hepatocytes by alpha-lipoic acid

Recent work shows that septic or endotoxic shock is associated with lipopolysaccharide and cytokine mixture-induced nitric oxide (NO) synthesis in liver. Here we found that DL-alpha-lipoic acid inhibited but other thiol-containing antioxidants such as glutathione and N-acetylcysteine enhanced lipopolysaccharide and cytokine mixture (referred as LPS/CM)-induced NO synthesis in hepatocytes. The inhibitory action of alpha-lipoic acid on hepatocyte NO synthesis was as potent as that of NG-monomethyl-L-arginine without obvious cytotoxicity. Deletion by diethylmaleate or inhibition by buthionine sulfoximine of intracellular glutathione caused a significant decrease in hepatocyte NO synthesis, implying that increased intracellular reduced glutathione levels could not be the reason for alpha-lipoic acid inhibited NO synthesis. alpha-Lipoic acid inhibition of NO synthesis seems to be from alpha-lipoic acid improved carbohydrate metabolism in hepatocytes. Since alpha-lipoic acid is an essential compound existing naturally in physiological systems, it may serve as both a research and therapeutic agent for sepsis.

Not only the nature of peptide but also the characteristics of cell membrane determine the antimicrobial mechanism of a peptide

The mechanisms of antimicrobial actions of magainin 2, buforin II and poly L-lysine against various Escherichia coli strains were studied. Poly L-lysine inhibited BL21, AD 434 and GroE+/DnaK+ growth without lysing the cell. Magainin 2 had a pore-forming activity on BL 21 and AD 434 membrane but could not inhibit the GroE+/DnaK+ growth in a nutrient-rich medium. Buforin II, which killed BL21 and AD 434 without cell membrane damage, lysed GroE+/DnaK+ to death. Once they were introduced into the cell by electroporation, all three peptides were able to inhibit cell growth at concentrations of 10 times lower than their MICs. These results indicate that the nature of the peptide and also the characteristics of the cell membrane determine the antimicrobial actions of a peptide.

Mitogenic-factor-dependent regulation of lipopolysaccharide and cytokine mixture-mediated hepatocyte nitric oxide synthesis in vitro

Hepatocellular mitogen (HGF and EGF) inhibited lipopolysaccharide and cytokine mixture (referred as LPS/CM)-induced NO synthesis and cellular injury in hepatocytes. Mitogenic inhibitors such as hydroxyurea and Wortmannin could not reverse EGF or HGF-inhibited NO production, whereas both of them showed some inhibitory effect on hepatocyte NO synthesis. Although activation of protein kinase C (PKC) by phorbol 12-myristate 13-acetate (PMA) had no effect on hepatocyte NO synthesis, deletion of PKC activity by long-term treatment of hepatocytes with PMA abolished LPS/CM-induced NO production. In addition, pretreatment of hepatocytes with HGF and EGF also blocked LPS/CM-induced NO synthesis in the hepatocyte. These results suggest that proliferating signal is not directly involved in mitogen-inhibited NO synthesis in the hepatocyte, and LPS/CM-mediated NO synthesis is associated with the metabolic/redox state of hepatocytes.

Protective effect of linoleic acid on IFN gamma-induced cellular injury in primary culture hepatocytes

We have previously demonstrated that treatment of hepatocytes with IFN gamma results a series of cellular injury processes, including DNA synthesis arrest, membrane breakage and apoptosis. In the present work, we show that IFN gamma suppresses cellular respiration and protein synthesis in hepatocytes, and that cellular respiration suppression is an early event in the IFN gamma-induced cellular injuries. Polyunsaturated fatty acids (PUFAs) increased cellular respiration of hepatocytes, but only linoleic acid showed some protective effect against IFN gamma-induced cellular respiration suppression. Linoleic acid also reduced other IFN gamma-mediated cellular injuries, including membrane breakage and protein synthesis inhibition. Like linoleic acid, fetal bovine serum also inhibited IFN gamma-induced cellular damage. Increased NAD levels were found in both IFN gamma-treated and non-treated hepatocytes following the addition of PUFAs, but clofibrate, a peroxisome proliferator, bromophenacyl bromide (BPB), an inhibitor of phospholipase, nordihydroguaiaretic acid (NDGA), an inhibitor of lipoxygenase, and arachidonic acid, a metabolite of linoleic acid, did not inhibit IFN gamma-induced cellular injury. In addition, the combination of linoleic acid and IFN gamma induced nitric oxide (NO) synthesis in hepatocytes. These results suggest that fatty acid may play an important role in liver homeostasis during chronic inflammatory states and sepsis.

Nitric oxide is not involved in lipopolysaccharide and cytokine mixture-induced cellular injuries in primary cultured hepatocytes

Nitric oxide (NO) from artificial NO donors induces cell death through complete inhibition of mitochondrial respiration of hepatocytes. Treatment of hepatocytes with lipopolysaccharide (LPS) and cytokine mixture (interferon gamma and tumor necrosis factor alpha) not only results in NO production but also causes cellular respiration suppression and cell death in hepatocytes. NG-monomethyl-L-arginine, a specific inhibitor of nitric oxide synthase, inhibits hepatocyte NO synthesis but cannot prevent hepatocytes from LPS and cytokine mixture-induced cellular injuries. Similarly, some metabolic intermediates capable of inhibiting hepatocyte NO synthesis cannot block LPS and cytokine mixture-mediated cellular injuries in hepatocytes. These results imply that lipopolysaccharide and cytokine mixture-induced cellular injuries and NO syntheses are parallel events, NO is not involved in LPS and cytokine mixture-induced cell damage.

Inhibition of lipopolysaccharide and cytokine mixture-mediated hepatocyte nitric oxide synthesis by dimethyl sulfoxide

Treatment and pretreatment of hepatocytes with 2% dimethyl sulfoxide (DMSO) inhibited lipopolysaccharide and cytokine mixture (LPS/CM)-mediated NO synthesis in hepatocytes without any obvious effects on cell viability. DMSO at concentrations of 0.5-4% stimulated DNA replication and increased albumin secretion in LPS/CM-treated hepatocytes. Genisein, a inhibitor of protein tyrosine kinase (PTK), inhibited LPS/CM-mediated NO synthesis in hepatocytes. These results suggest that PTK is critical for hepatocyte NO synthesis, and DMSO-inhibited NO synthesis may be associated with prevention of LPS/CM-induced PTK activation in hepatocytes.

Role of metabolic intermediates in lipopolysaccharide/cytokine-mediated production of nitric oxide in isolated mouse hepatocytes

Induction of nitric oxide synthase by bacterial endotoxin in vivo can be mimicked by treating cultured hepatocytes with a combination of lipopolysaccharide and cytokines (LPS/cytokines), but the role of LPS/cytokine-induced nitric oxide in hepatocyte glucose metabolism is ambiguous. In this study, intermediary metabolite effects on LPS/cytokine-induced hepatocyte nitric oxide synthesis were examined. Pyruvate, lactate, oxaloacetate, and fumarate all showed some inhibitory effects on hepatocyte nitric oxide synthesis. However, these metabolic intermediates could not improve the mitochondrial respiration of LPS/cytokine-treated hepatocytes. Phosphoenolpyruvate carboxykinase activity (or flux) relating factors, glucocorticoids and cAMP, also blocked LPS/cytokine-induced nitric oxide synthesis. Insulin was much less potent than cAMP and glucocorticoids, and phorbol ester did not show any effect on hepatocyte nitric oxide synthesis. These results suggest that LPS/cytokine-induced nitric oxide synthesis is related, at least partly, to phosphoenolpyruvate carboxykinase activity (or flux) in hepatocytes.