OBJECTIVES: Amid the spread of coronavirus disease 2019 (COVID-19), with its high infectivity, we have relied on mathematical models to predict the temporal evolution of the disease. This paper aims to show that, due to active behavioral changes of individuals and the inherent nature of infectious diseases, it is complicated and challenging to predict the temporal evolution of epidemics. METHODS: A modified susceptible-exposed-infectious-hospitalized-removed (SEIHR) compartment model with a discrete feedback-controlled transmission rate was proposed to incorporate individuals’ behavioral changes into the model. To figure out relative uncertainties in the infection peak time and the fraction of the infected population at the peak, a deterministic method and 2 stochastic methods were applied. RESULTS: A relatively small behavioral change of individuals with a feedback constant of 0.02 in the modified SEIHR model resulted in a peak time delay of up to 50% using the deterministic method. Incorporating stochastic methods into the modified model with a feedback constant of 0.04 suggested that the relative random uncertainty of the maximum fraction of infections and that of the peak time for a population of 1 million reached 29% and 9%, respectively. Even without feedback, the relative uncertainty of the peak time increased by up to 20% for a population of 100,000. CONCLUSIONS It is shown that uncertainty originates from stochastic properties of infections. Without a proper selection of the evolution scenario, active behavioral changes of individuals could serve as an additional source of uncertainty.

OBJECTIVES: Amid the spread of coronavirus disease 2019 (COVID-19), with its high infectivity, we have relied on mathematical models to predict the temporal evolution of the disease. This paper aims to show that, due to active behavioral changes of individuals and the inherent nature of infectious diseases, it is complicated and challenging to predict the temporal evolution of epidemics. METHODS: A modified susceptible-exposed-infectious-hospitalized-removed (SEIHR) compartment model with a discrete feedback-controlled transmission rate was proposed to incorporate individuals’ behavioral changes into the model. To figure out relative uncertainties in the infection peak time and the fraction of the infected population at the peak, a deterministic method and 2 stochastic methods were applied. RESULTS: A relatively small behavioral change of individuals with a feedback constant of 0.02 in the modified SEIHR model resulted in a peak time delay of up to 50% using the deterministic method. Incorporating stochastic methods into the modified model with a feedback constant of 0.04 suggested that the relative random uncertainty of the maximum fraction of infections and that of the peak time for a population of 1 million reached 29% and 9%, respectively. Even without feedback, the relative uncertainty of the peak time increased by up to 20% for a population of 100,000. CONCLUSIONS It is shown that uncertainty originates from stochastic properties of infections. Without a proper selection of the evolution scenario, active behavioral changes of individuals could serve as an additional source of uncertainty.

Metabolic acidosis (MA) is associated with increased proteolysis, increased osteoclast activity and blunted cardiac muscle response, but the effect of MA on various clinic al parameters in CAPD patients is not well known. To evaluate the effects of MA on serum albumin level and other nutritional parameters in CAPD patients, we studied 106 CAPD patients retrospectively who have had monthly biochemical measurement and urea kinetic studies every 6 months for more than 2 years. The patients were divided into three groups according to their mean total CO2 (tCO2) level of the 2-year follow-up (Group l; mean tCO2 < 22mM/L, Group ll; 22mM/L < or = mean tCO2 < 26mM/L, and Group lll; mean tCO2 > or = 26mM/L), and the clinical, biochemical, and urea kinetic data were compared among the three groups. 1)The mean age of the subjects was 46.9+/-12.2 years with a sex ratio of 1.2:1, the mean CAPD duration 28.3+/-21.8 months, mean body weight (Bwt) 59.0+/-8.9kg, %Bwt/IBW 104.1+/-11.5%, %LBM/Bwt 75.5+/-11.1% and well-nourished patients by subjective global assessment (SGA) were 65%. 2)The mean BUN, creatinine, total protein and albumin of all patients were 55.6+/-13.6mg/dL, 12.3+/-3.5mg/dL, 6.6+/-0.7g/dL and 4.0+/-0.4g/dL, respectively. In urea kinetic study, the mean NPCR, weekly Kt/ Vurea, SCCr and RRF were 0.96+/-0.16g/kg/day, 2.02+/-0.37, 63.7+/-18.4L/week/1.73m2, and 0.99+/-1.32ml/ min, respectively. 3)The mean age was significantly higher in group l (51.0+/-10.8) than those of group ll (47.0+/-12.4) and lll (42.6+/-11.4) (P<0.05). %Bwt/IBW of group l (114.4+/-15.8%) was also significantly higher than those of group ll (104.6+/-12.6%) and lll (103.5+/-13.7 %) (P<0.05), but there were no significant differences in sex ratio, CAPD duration, %LBM/Bwt, and SGA among the three groups. 4)The mean tCO2 in group l, group ll, and group lll were 20.6+/-1.2mM/L, 23.9+/-1.1mM/L, and 27.3+/-0.8mM/L, respectively. Compared to group lll, group l had significantly higher BUN (61.1+/-14.3 vs. 46.1+/-7.2mg/dL, P<0.05) and serum albumin (4.04+/-0.31 vs. 3.75+/-0.39g/dL, P<0.05), in spite of comparable dialysis dose and albumin loss into dialysate. 5)NPCR (1.02+/-0.21g/kg/day vs. 0.88+/-0.14g/kg/ day, P<0.05) and ultrafiltration volume (1.4+/-0.4 vs. 1.0+/-0.3, P<0.05) were significantly higher in group l than those of group lll. But there were no significant differences in Kt/Vurea, SCCr, RRF, and 24-hour dialysate loss of protein/albumin among the three groups. 6)No differences were observed among the three groups in the changes of body weight, %Bwt/IBW, %LBM/Bwt, BUN, albumin, NPCR, and RRF from the baseline values after the 2-year follow-up. 7)There were significant inverse correlations between the mean tCO2 level and NPCR (r=-0.33, P<0.001), %Bwt/IBW (r=-0.32, P<0.001), RRF (r=-0.29, P<0.005), and serum albumin level (r=-0.24, P<0.05). But, creatinine, %LBM/Bwt, and Kt/Vurea did not show any correlation with the mean tCO2 level. 8)Using stepwise multiple regression analysis, NPCR (beta=-0.3491, P<0.001), %Bwt/IBW (beta=-0.046, P<0.001), and ultrafiltration volume (beta=-0.0012, P< 0.005) were independent factors affecting the mean tCO2 level. In conclusion, low total CO2 level in long-term CAPD patients may reflect increased protein intake and mild to moderate degree of metabolic acidosis may not affect the nutritional status of well-dialyzed CAPD patients.
Acidosis* ; Body Weight ; Creatinine ; Dialysis ; Follow-Up Studies ; Humans ; Myocardium ; Nutritional Status ; Osteoclasts ; Peritoneal Dialysis, Continuous Ambulatory* ; Proteolysis ; Retrospective Studies ; Serum Albumin* ; Sex Ratio ; Ultrafiltration ; Urea

Wernicke's encephalopathy is a reversible but potentially critical disease caused by thiamine deficiency. Most patients complain of symptoms such as ophthalmoplegia, ataxia and confusion. Heavy alcohol drinking is commonly associated with the disease, but other clinical conditions also can provoke it. In pregnant women, hyperemesis gravidarum can lead to the depletion of body thiamine due to poor oral intake and a high metabolic demand. We report a case of Wernicke's encephalopathy following hyperemesis gravidarum in a 36-year-old female at 20 weeks of pregnancy, who visited our hospital because of shock with vaginal bleeding. This case suggests that although the initial presentation may include atypical symptoms (e.g., shock or bleeding), Wernicke's encephalopathy should be considered, and thiamine replacement should be performed in pregnant women with neurologic symptoms and poor oral intake.
Acute Kidney Injury ; Adult ; Alcohol Drinking ; Ataxia ; Female ; Humans ; Hyperemesis Gravidarum* ; Neurologic Manifestations ; Ophthalmoplegia ; Pregnancy ; Pregnant Women ; Shock ; Thiamine ; Thiamine Deficiency ; Uterine Hemorrhage ; Wernicke Encephalopathy*

Background and Objectives: This study aimed to examine factors of poor outcome by analyzing the outcomes of bilateral subthalamic deep brain stimulation in Parkinson’s disease after 3 years. Methods: We assumed that patients who could not manage independent life in their best stimulationon/medication-on condition after a defi ned period might not have been a good surgical candidate. A poor outcome is defi ned as a failure to maintain functional independence at three years during a stimulation-on/medication-on state. Results: A total of 84 patients underwent bilateral subthalamic deep brain stimulation and all were followed up for 3 years. We excluded one patient who had intracranial hemorrhage. Twenty-one patients of the 83 patients could not keep up independent life even during their best condition for the following reasons: freezing in 15 patients, dementia in 5, depression in 3, musculoskeletal problems in 7, and cancer in one patient. Conclusions: Many patients could not keep up independent life during their best condition as early as three years after deep brain stimulation. Musculoskeletal problems were one major cause of disabilities, as were freezing and dementia. We emphasize that musculoskeletal problems need more attention in the preoperative screening of deep brain stimulation candidates and during the follow up.

PURPOSE: The authors tried to analyze the distribution of associated intra-articular lesions using the arthroscope in excision of popliteal cyst observed in adults. MATERIALS AND METHODS: The authors examined intra-articular lesions identified by arthroscopic examination on 113 adult patients(117 cases) who were diagnosed as having popliteal cyst that didn't respond to the conservative treatment. And for the operation, intra-articular examination using arthroscope was performed in supine position and the authors performed one-stage excision of cyst without position change of patients. RESULTS: In 104 cases(88.9%) of total 117 cases, combined intra-articular lesions were identified, Among these, most cases were 72 cases(69.2%) of degenerative chondral lesion and 31 cases(29.8%) of meniscus tear. Communication between cyst and joint was observed in 63 cases(53.8%). There was neither postoperative complication nor recurrence of cyst during out-patient follow-up periods. CONCLUSIONs: In cases of adult patient who have popliteal cyst that doesn't respond to the conservative treatment, possible associated intra-articular lesions should be considered., and arthroscopic examination and proper treatment far those associated lesions are thought to lower the recurrence rate.
Adult* ; Arthroscopes* ; Follow-Up Studies ; Humans ; Joints ; Knee ; Outpatients ; Popliteal Cyst* ; Postoperative Complications ; Recurrence ; Supine Position

OBJECTIVE: This study was conducted to compare the effects of low frequency needle transcutaneous electrical nerve stimulation (TENS) and high frequency needle TENS on experimental pain threshold. METHOD: Twenty two healthy adult subjects were assigned randomly to a low-TENS group or to a high-TENS group. Experimental pain threshold at forearm was determined with pain threshold of electrical simulation using surface electrode and needle electrode. RESULTS: Low-TENS group showed that pain relief was developed after 10 minutes and persisted 3 hours after treatment cessation. Low-TENS group showed a significant increase in experimental pain threshold opposing to high TENS group. CONCLUSION: This results suggest that effect of low frequency needle TENS therapy is better and longer than high frequency needle TENS therapy.
Adult* ; Electrodes ; Forearm ; Humans ; Needles* ; Pain Threshold* ; Transcutaneous Electric Nerve Stimulation* ; Withholding Treatment

Background: Selecting effective products among the various types of silicone gel sheets can be challenging for surgeons. Therefore, we assessed the effect of silicone gel sheet thickness on surgical scars in pediatric and adolescent patients. Methods: From December 2017 to May 2018, we identified patients aged 1–19 years who underwent excision. Among these patients, those who were prescribed 0.3-mm or 1.0-mm-thick silicone sheets were selected. Scars were subjectively evaluated using a questionnaire consisting of seven items. Objective evaluation was performed by two plastic surgeons using the Vancouver Scar Scale (VSS). Results: The mean age of the 49 selected patients was 9.78 years. The patients were divided into two groups according to the thickness of the silicone gel sheet used (0.3 mm vs. 1.0 mm). Objective evaluation of the patients’ scars revealed more favorable results in the 0.3 mm group than in the 1.0 mm group (P=0.010). Multivariate analysis of VSS scores indicated that the resulting scars in cases involving the trunk were of poorer quality than those involving facial areas (P=0.015). Additionally, favorable (i.e., below-average) VSS scores were significantly less likely in patients with longer scars (odds ratio, 0.896; 95% confidence interval, 0.834–0.963; P=0.003) or thicker silicone sheets (odds ratio, 0.085; 95% confidence interval, 0.011–0.699; P=0.019). Conclusions The use of thinner silicone gel sheets in children and adolescents resulted in better scars according to subjective evaluations, underscoring the importance of compliance in pediatric patients. The type of operation and surgical lesion should also be considered when planning the management of surgical scars.

Purpose: The purpose of present study was to evaluate the effect of changing structural stability of wax disc on the fit of prosthesis when the milling proceeded in order. Materials and methods: Prepared maxillary left first molar was used to fabricate a Ni-Cr alloy reference model. This was scanned to design crown and then wax pattern was milled, invested and cast to fabricate prosthesis. The wax patterns located in a row centrally within a single wax disc were set into a total of five groups ranging from WM1 group that was first milled to WM5 group that was last milled and the number of each group was set as 10. Silicone replica technique was used to measure the marginal gap, axial internal gap, line angle internal gap, occlusal internal gap. Data was evaluated with one-way ANOVA with significance level set at α = .05 and then Tukey HSD test was conducted for post analysis. Results: Marginal gap measured in each group, it was 40.41 ± 2.15 µm in WM1group, 40.44 ± 2.23 µm in WM2 group, 39.96 ± 2.25 µm in WM3 group, 39.96 ± 2.48 µm in WM4 group, and 40.57 ± 2.53 µm in WM5 group. No significant difference was found between groups. The significant difference between the groups was also not found in the axial internal gap, line angle internal gap, and occlusal internal gap. Conclusion Internal and marginal fit of single crown to the sequential order of milling processing in the single machinable wax disc did not seem to be affected by the sequence.

Diarrea-associated hemolytic uremic syndrome (HUS) is very rare in adults. Few reports are available on clinical features and plasma exchange in adult patients with diarrhea-associated HUS in Korea. We retrospectively examined the records of five adult patients with diarrhea-associated HUS admitted to Samsung Seoul Hospital between January 1995 and December 1997. If the patient had neurologic abnormalities, or there was rapid clinical deterioration, with the hematocrit decreasing below 20%, the platelet count falling below 10,000/mm3, the creatinine concentration increasing above 5.0 mg/dl, plasma exchange was begun. There were 4 females and 1 male. Patients ranged in age from 16 to 61 years. All patients presented with diarrhea and abdominal pain, and 3 patients had bloody diarrhea. The mean time between the onset of diarrhea and thrombocytopenia was 4.4+/-1.9 days (range, 1 to 6). All patients received 7 to 24 plasma exchanges. The mean exchanged plasma volume was 1.1+/-0.2 times of patients own plasma volume. The pattern of clinical response to plasma exchange was initial normalization of platelet count (8.0+/-3.8 days), followed by normalization of LDH level (20.2+/-14.5 days) and creatinine concentration (25.8+/-13.8 days). Metabolic alkalosis developed in two patients undergoing daily plasma exchange. We successfully managed the metabolic alkalosis with continuous venovenous hemofiltration. The mean duration of hospitalization was 28.8+/-11.2days (range, 20 to 42). All patients successfully recovered without any sequale. Although this study is based on small case series, we suggested that plasma exchange may improve the outcome in adult diarrhea-associated HUS.
Abdominal Pain ; Adult* ; Alkalosis ; Creatinine ; Diarrhea ; Female ; Hematocrit ; Hemofiltration ; Hemolytic-Uremic Syndrome* ; Hospitalization ; Humans ; Korea ; Male ; Plasma Exchange* ; Plasma Volume ; Plasma* ; Platelet Count ; Retrospective Studies ; Seoul ; Thrombocytopenia