Clinicians and healthcare decision-makers conduct their clinical practice based on the results of clinical trials. However, some health problems remain unresolved; in such cases, further research is required. To ensure reliable research results, it is important to understand the study design and conduct well-designed clinical trials. Many study designs can be chosen within the two broad categories of observational and interventional. Clinical studies have a variety of designs, including case series, case-control, cross-sectional, and prospective and retrospective cohort studies. Well-designed clinical studies can clarify important differences between treatment options and provide data on long-term drug efficacy and safety. Interpreting the results of clinical trials can be difficult because weaknesses in research design, data collection methods, analytic methods, and reporting can compromise their value and usefulness. However, although randomized controlled trials are limited owing to ethical and practical issues, they are optimal for investigating the effects of therapy and establishing causality. Here we present an overview of different clinical research designs and review their advantages and limitations.

OBJECTIVE: Workload is known to affect the hypothalamus-pituitary-adrenal axis. Although many studies had revealed that job stress related factors could affect the neuroendocrine system among blue-collar workers, these studies had limitations as they had not evaluated the workload by objective methods which took into consideration individual physiological differences. This study was conducted to evaluate the effects of physical workload adjusted job stress on cortisol regulation by using objective tools for workers having various job tasks. METHODS: Among 110 foundry workers, shipyard workers, and fine machine assemblers for whom saliva samples were obtained, 102 without any past history of conditions that could affect hormonal regulation such as diabetes, and hypertension were included in this study. Among the 102 study participants, 15 workers whose saliva for morning or afternoon or heart rate monitoring data was not attained were excluded from the final analysis. Workload was evaluated by RHR (relative heart rate) using a heart rate monitor, and job stress was evaluated by Karasek's Job Content Questionnaire. Saliva samples were gathered during 8 - 9 am and 5 - 6 pm, and salivary cortisol levels were analysed by radioimmunoassay. RESULTS: After adjusting several variables which could effect cortisol secretion including job stress, among the higher RHR group morning salivary cortisol level was increased (beta=60.32, S.E.=26.35, p=0.0266), afternoon salivary cortisol level was decreased (beta=-7.43, S.E.=29.73, p=0.8044), and salivary cortisol level difference between morning and afternoon was increased (beta=72.10, SE=35.50, p=0.0509). CONCLUSIONS: As physical workload increases morning cortisol level, which is caused by the effect of arousal, and decreases afternoon cortisol level, which is caused by exhaustion, physical workload enlarges the width of diurnal cortisol variance. Therefore, physical exhaustion due to excessive workload could have adverse effects on the neuroendocrine system.
Arousal ; Axis ; Heart ; Heart Rate ; Hydrocortisone* ; Hypertension ; Neurosecretory Systems ; Questionnaires ; Radioimmunoassay ; Saliva

Localized tenosynovial giant cell tumor (TGCT) usually occurs in the hand and foot regions. However, localized TGCT with extensive cartilaginous metaplasia is rare, especially in the tendon sheath of the toe. Here, we report a case of localized TGCT with cartilaginous metaplasia in a 57-year-old man. The tumor presented as a lobular mass measuring 2.2 cm in its greatest dimension and arose in the flexor digitorum tendon sheath of the right 2nd toe. Clinically, the mass was palpable 1 year ago and brought pain during walking. Microscopically, the mass was composed of focal conventional TGCT and cartilaginous components. The conventional TGCT areas consisted of mononuclear cells, multinucleated giant cells, and hemosiderin deposition. The chondroid areas were extensive and comprised more than 90% of the whole tumor. In this case, the mononuclear cells in the conventional TGCT areas showed focal immunohistochemical staining for podoplanin and S100 protein as well as diffuse staining for CD68, which is consistent with the staining pattern of conventional TGCT. The mononuclear cells in the chondroid areas were focal positive for podoplanin and diffuse positive for S100 protein. Chondroid metaplasia in diffuse TGCT has been reported in 10 cases involving the temporomandibular, elbow, and hip joints. However, there has been no report of a localized form of chondroid TGCT involving an extra-articular region.
Elbow ; Foot ; Giant Cell Tumors* ; Giant Cells ; Hand ; Hemosiderin ; Hip Joint ; Humans ; Metaplasia ; Middle Aged ; Staphylococcal Protein A ; Tendons ; Toes* ; Walking

PURPOSE: As 5-fluorouracil (5-FU) has previously exhibited antitumor activity and few adverse effects in the treatment of breast cancer, we aimed to specifically assess the benefits of orally administered 5-FU in hormone receptor-negative small breast cancer. METHODS: We retrospectively identified patients with pT1aN0 and hormone receptor-negative breast cancer who underwent surgery between 1993 and 2008 at Asan Medical Center. Patients were divided into two cohorts based on adjuvant doxifluridine (Didox; Shin Poong Pharm. Co., Ltd.) administration, and the disease-free survival (DFS) and cancer-specific survival (CSS) was assessed for each cohort. RESULTS: Both cohorts had similar ages and tumor sizes. The DFS and CSS did not significantly differ between the groups (p=0.399 and p=0.126, respectively). When the cohorts were assessed according to human epidermal growth factor receptor 2 (HER2) status, doxifluridine significantly improved DFS among patients with T1aN0 and HER2-positive breast cancer (p=0.037). CONCLUSION: Doxifluridine did not yield a significant reduction in DFS events in hormone receptor-negative early breast cancer. However, a clear benefit was observed in hormone receptor-negative, HER2-positive T1aN0 breast cancer patients.