Evaluation of Vancomycin TDM Strategies: Prediction and Prevention of Kidney Injuries Based on Vancomycin TDM Results

The current guidelines for therapeutic drug monitoring (TDM) of vancomycin suggest a target 24-hour area under the curve (AUC 0-24 ) of 400 to 600 mg*h/L for serious methicillinresistant Staphylococcus aureus infections. In this study, the predictabilities of acute kidney injury (AKI) of various TDM target parameters, target levels, and sampling methods were evaluated in patients who underwent TDM from January 2020 to December 2020. The AUC 0-24 and trough values were calculated by both one- and two-point sampling methods, and were evaluated for the predictability of AKI. Among the AUC 0-24 cutoff comparisons, the threshold value of 500 mg*h/L in the two sampling methods was statistically significant (P = 0.042) when evaluated for the predictability of AKI. Analysis by an receiver operating characteristic curve estimated an AUC 0-24 cutoff value of 563.45 mg*h/L as a predictor of AKI, and was proposed as the upper limit of TDM target.

Korean clinical practice guidelines for the diagnosis of hereditary hemolytic anemia

Although the prevalence of hereditary hemolytic anemia (HHA) is relatively low in Korea, it has been gradually increasing in recent decades due to increment in the proportions of hemoglobinopathies from immigrants of South East Asia, raising awareness of the disease among clinicians, and advances in diagnostic technology. As such, the red blood cell (RBC) Disorder Working Party (WP), previously called HHA WP, of the Korean Society of Hematology (KSH) developed the Korean Standard Operating Procedures (SOPs) for the diagnosis of HHA in 2007. These SOPs have been continuously revised and updated following advances in diagnostic technology [e.g., flow cytometric osmotic fragility test (FOFT) and eosin-5-maleimide (EMA) binding test], current methods for membrane protein or enzyme analysis [e.g., liquid chromatography-tandem mass spectrometry (LC-MS/MS), ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), high-performance liquid chromatography (HPLC)], and molecular genetic tests using next-generation sequencing (NGS). However, the diagnosis and treatment of HHA remain challenging as they require considerable experience and understanding of the disease. Therefore, in this new Korean Clinical Practice Guidelines for the Diagnosis of HHA, on behalf of the RBC Disorder WP of KSH, updated guidelines to approach patients suspected of HHA are summarized. NGS is proposed to perform prior to membrane protein or enzyme analysis by LC-MS/MS, UPLC-MS/MS or HPLC techniques due to the availability of gene testing in more laboratories in Korea. We hope that this guideline will be helpful for clinicians in making diagnostic decisions for patients with HHA in Korea.

Suppressive Effect of CYM50358 S1P4 Antagonist on Mast Cell Degranulation and Allergic Asthma in Mice

Levels of sphingosine 1-phosphate (S1P), an intercellular signaling molecule, reportedly increase in the bronchoalveolar lavage fluids of patients with asthma. Although the type 4 S1P receptor, S1P4 has been detected in mast cells, its functions have been poorly investigated in an allergic asthma model in vivo. S1P4 functions were evaluated following treatment of CYM50358, a selective antagonist of S1P4, in an ovalbumin-induced allergic asthma model, and antigen-induced degranulation of mast cells. CYM50358 inhibited antigen-induced degranulation in RBL-2H3 mast cells. Eosinophil accumulation and an increase of Th2 cytokine levels were measured in the bronchoalveolar lavage fluid and via the inflammation of the lungs in ovalbumin-induced allergic asthma mice. CYM50358 administration before ovalbumin sensitization and before the antigen challenge strongly inhibited the increase of eosinophils and lymphocytes in the bronchoalveolar lavage fluid. CYM50358 administration inhibited the increase of IL-4 cytokines and serum IgE levels. Histological studies revealed that CYM50358 reduced inflammatory scores and PAS (periodic acid–Schiff)-stained cells in the lungs. The pro-allergic functions of S1P4 were elucidated using in vitro mast cells and in vivo ovalbumin-induced allergic asthma model experiments. These results suggest that S1P4 antagonist CYM50358 may have therapeutic potential in the treatment of allergic asthma.

Suppressive Effect of CYM50358 S1P4 Antagonist on Mast Cell Degranulation and Allergic Asthma in Mice

Levels of sphingosine 1-phosphate (S1P), an intercellular signaling molecule, reportedly increase in the bronchoalveolar lavage fluids of patients with asthma. Although the type 4 S1P receptor, S1P4 has been detected in mast cells, its functions have been poorly investigated in an allergic asthma model in vivo. S1P4 functions were evaluated following treatment of CYM50358, a selective antagonist of S1P4, in an ovalbumin-induced allergic asthma model, and antigen-induced degranulation of mast cells. CYM50358 inhibited antigen-induced degranulation in RBL-2H3 mast cells. Eosinophil accumulation and an increase of Th2 cytokine levels were measured in the bronchoalveolar lavage fluid and via the inflammation of the lungs in ovalbumin-induced allergic asthma mice. CYM50358 administration before ovalbumin sensitization and before the antigen challenge strongly inhibited the increase of eosinophils and lymphocytes in the bronchoalveolar lavage fluid. CYM50358 administration inhibited the increase of IL-4 cytokines and serum IgE levels. Histological studies revealed that CYM50358 reduced inflammatory scores and PAS (periodic acid–Schiff)-stained cells in the lungs. The pro-allergic functions of S1P4 were elucidated using in vitro mast cells and in vivo ovalbumin-induced allergic asthma model experiments. These results suggest that S1P4 antagonist CYM50358 may have therapeutic potential in the treatment of allergic asthma.

A Survey on the Current Status of Neonatal Physical Therapy in South Korea

Purpose@#This study aimed to investigate and report the current status of physical therapy (PT) performed in Korean neonatal intensive care units (NICU) to present foundational data that promotes the advances in neonatal PT in Korea. @*Methods@#Based on the Health Insurance Review and Assessment (HIRA) data, we administered a questionnaire survey to 74 hospitals (39 tertiary and 35 general hospitals) in Korea equipped with a NICU and pediatric PT unit. We developed a 32-item questionnaire with reference to previous Korean studies. The questionnaires were distributed and retrieved via regular mail and an online system. @*Results@#Of the 74 hospitals, 58 (78%) practiced neonatal PT and the duration of each session significantly differed according to the hospital rating. PT was given, depending on clinical symptoms, to infants who were preterm and low birth-weight (96.5%), had brain and spinal cord diseases (84.5%), had pathological tonus (94.8%), with respiratory problems (65.5%), for range of motion exercises (82.8%), for neurodevelopment approaches (72.4%), and for positioning (70.7%). Interdisciplinary meetings were held to share clinical decision-making in 17.2% of the hospitals surveyed and parent-participating education to ensure a family-centered approach was offered in 63.8% of the hospitals. The barriers of neonatal PT included low insurance fees, insufficient awareness of colleagues, and the severity of the patient. @*Conclusion@#This study is the first report of the current status of neonatal PT in Korea. The findings of this study will serve as foundational data to review the current neonatal PT practice and promote further advances.

A Survey on the Current Status of Neonatal Physical Therapy in South Korea

Purpose@#This study aimed to investigate and report the current status of physical therapy (PT) performed in Korean neonatal intensive care units (NICU) to present foundational data that promotes the advances in neonatal PT in Korea. @*Methods@#Based on the Health Insurance Review and Assessment (HIRA) data, we administered a questionnaire survey to 74 hospitals (39 tertiary and 35 general hospitals) in Korea equipped with a NICU and pediatric PT unit. We developed a 32-item questionnaire with reference to previous Korean studies. The questionnaires were distributed and retrieved via regular mail and an online system. @*Results@#Of the 74 hospitals, 58 (78%) practiced neonatal PT and the duration of each session significantly differed according to the hospital rating. PT was given, depending on clinical symptoms, to infants who were preterm and low birth-weight (96.5%), had brain and spinal cord diseases (84.5%), had pathological tonus (94.8%), with respiratory problems (65.5%), for range of motion exercises (82.8%), for neurodevelopment approaches (72.4%), and for positioning (70.7%). Interdisciplinary meetings were held to share clinical decision-making in 17.2% of the hospitals surveyed and parent-participating education to ensure a family-centered approach was offered in 63.8% of the hospitals. The barriers of neonatal PT included low insurance fees, insufficient awareness of colleagues, and the severity of the patient. @*Conclusion@#This study is the first report of the current status of neonatal PT in Korea. The findings of this study will serve as foundational data to review the current neonatal PT practice and promote further advances.

Inhibition of Cross-Reactive Carbohydrate Determinant–Specific IgEs Reduce False Positive Reponses to Multiple Allergen Simultaneous Test–Immunoblot Assay: A Case Study

Cross-reactive carbohydrate determinants (CCDs) are simple carbohydrates linked to amino acid chains; they are found in pollens, vegetable foods, insect, and Hymenoptera venoms and are broadly cross-reactive with CCD-specific IgE antibodies. A man in his fifties was evaluated using a multiple allergen simultaneous test–immunoblot assay. On the PROTIA Allergy-Q 64 inhalant panel (ProteomeTech, Korea), reactions to 37 of 59 antigens were observed except mammalian antigens, and cross-reactivity owing to anti-CCD antibodies was suspected. After ProGlycAn CCD-blocker (ProGlycAn, Austria) treatment, the patient exhibited no response to CCD allergens, and the number of allergens showing positive reactions was reduced to 15. We further tested a total of 7 samples from patients who were suspected to have CCD-related cross-reactivity. For these 8 patients, the average number of positive reactions to allergens was reduced from 33 (range 24-36) to 8 (range 0-19) after CCD-blocker treatment. We concluded that CCD-blocker treatment in sample with anti-CCD antibodies can reduce the false positive reponse and provide more specific information about allergens.

A Multiplex Phytosterol Assay Utilizing Gas Chromatography-Mass Spectrometry for Diagnosis of Inherited Lipid Storage Disorders

No abstract available.

Identification of MicroRNA Related to the CD34+ Cell Fraction of Cord Blood Stem Cells / 대한수혈학회지

BACKGROUND: Cord blood (CB) is a reliable source of hematopoietic stem cells, and its utilization in stem cell transplantation is increasing continuously. The CD34+ cell count is arguably one of the most important parameters for evaluating the quality of a cord blood unit (CBU), but there is little evidence on the post-genetic modifications that can affect the CD34+ cell counts. In this study, the difference in the miRNA expression profiles between low and high CD34+ CBU was evaluated. METHODS: Paired CB and maternal samples with low (0.9%) were selected for analysis. MicroRNA profiling was performed, and differentially expressed miRNA were identified. In addition, gene ontology analysis was conducted on the miRNA to elucidate the genes that could potentially affect the CD34+ cell count. RESULTS: Ten miRNA were identified to show significantly different expression between the low and high CD34+ groups. Four of the 10 miRNA were hematopoiesis-related (miR-199a-5p, miR-22-5p, miR-140-5p, and miR-181b-5p). From a total of 119 associated genes, nine (CALCA, FARP2, FSHR, ITGAM, MELK, MLF1, PRG4, TREM2 and VCAM1) were associated with two or more of the aforementioned miRNA. CONCLUSION: This is the first study that examined the difference in the miRNA expression profiles between high and low CD34+ CB cells and revealed the relevant genes associated with hematopoiesis. These results provide basic insight into the genetic processes involving hematopoietic stem cell proliferation.

Anesthetic management with extracorporeal membrane oxygenation in a patient with acute airway obstruction after inhalation burn injury: A case report

A 36-year-old woman was admitted to the intensive care unit because of an inhalation burn injury. Five days after admission, she developed dyspnea and hypercarbia. Therefore, fiberoptic bronchoscopy was performed through the endotracheal tube, which revealed foreign bodies in the tube. Tracheostomy was performed to remove, albeit incompletely, the foreign bodies (endotracheal debris). As sudden movement of the patient or airway reaction could cause the foreign bodies to move deeper into the bronchus during manipulation of the rigid bronchoscope, general anesthesia was induced and maintained by using total intravenous anesthesia with extracorporeal membrane oxygenation (ECMO). The foreign bodies were successfully removed without any other complications. This case showed that sloughed endobronchial debris after an inhalation burn injury caused acute airway obstruction. In such cases, alternative ventilation methods such as tracheostomy and ECMO may have to be applied, which can support a surgeon to focus on the procedure regardless of prolonged procedural time.

Anti-inflammatory effects of traditional mixed extract of medicinal herbs (MEMH) on monosodium urate crystal-induced gouty arthritis / 中国天然药物

Korean oriental medicine prescription is widely used for the treatment of gouty diseases. In the present study, we investigated anti-inflammatory effects of modified Korean herbal formulation, mixed extract of medicinal herbs (MEMH), and its modulatory effects on inflammatory mediators associated with gouty arthritis. Both in vitro and in vivo studies were carried out to assess the anti-inflammatory efficacy of MEMH on monosodium urate (MSU) crystals-induced gouty inflammation. MSU crystals stimulated human chondrosarcoma cell line, SW1353, and human primary chondrocytes were treated with MEMH in vitro. The expression levels of pro-inflammatory mediators and metalloproteases were analyzed. The effect of MEMH on NFκB signaling pathway in SW1353 cells was examined. Effect of MEMH on the mRNA expression level of pro-inflammatory mediators and chemotactic factor from human monocytic cell line, THP-1, was also analyzed. The probable role of MEMH in the differentiation process of osteoblast like cells, SaOS-2, after MSU treatment was also observed. To investigate the effects of MEMH in vivo, MSU crystals-induced ankle arthritic model was established. Histopathological changes in affected joints and plasma levels of pro-inflammatory mediators (IL-1β and TNFα) were recorded. MEMH inhibited NFκB signaling pathway and COX-2 protein expression in chondrocytes. MSU-induced mRNA expressions of pro-inflammatory mediators and chemotactic cytokines were suppressed by MEMH. In MSU crystals-induced ankle arthritic mouse model, administration of MEMH relieved inflammatory symptoms and decreased the plasma levels of IL-1β and TNFα. The results indicated that MEMH can effectively inhibit the expression of inflammatory mediators in gouty arthritis, demonstrating its potential for treating gouty arthritis.

Clinical Comparison of Influenza A and B Virus Infection in Hospitalized Children

PURPOSE: The objective of this study was to compare the clinical characteristics of influenza A and B infections and analyze the effect of oseltamivir in hospitalized children. METHODS: We investigated children under the age of 15, who were diagnosed with influenza A/H1N1, A/H3N2, or B from January to April 2014. The subjects were admitted to the Changwon Fatima Hospital and diagnosed using a rapid antigen test from nasopharyngeal swabs. The medical records of the patients were retrospectively reviewed. RESULTS: A total of 302 pediatric patients with influenza were enrolled. Influenza B infection was the most common type (n=187, 61.9%), followed by A/H3N2 (n=100, 33.1%) and A/H1N1 (n=15, 5.0%). Compared to patients diagnosed with influenza A, patients diagnosed with influenza B were older (P=0.005), and the duration of fever was significantly longer (P=0.001). A total of 161 patients (53.3%) had been vaccinated against influenza during the season, before admission. Among the patients infected with A/H3N2 and B, the duration of fever was shorter in oseltamivir recipients compared to oseltamivir non-recipients (P=0.026 and P=0.004, respectively). CONCLUSIONS: There were significant differences between influenza A and B groups in terms of age, demographics, and clinical course. Although the effectiveness of oseltamivir on influenza differs according to the type of influenza, our data provides evidence that oseltamivir is beneficial for both A and B infections.

Increase in Antibiotic-Resistant Gram-Negative Bacterial Infections in Febrile Neutropenic Children / 감염과화학요법

BACKGROUND: The incidence of bacteremia caused by Gram-negative bacteria has increased recently in febrile neutropenic patients with the increase of antibiotic-resistant Gram-negative bacterial infections. This study aimed to identify the distribution of causative bacteria and the proportion of antibiotic-resistant bacteria in bacteremia diagnosed in febrile neutropenic children. MATERIALS AND METHODS: The medical records of febrile neutropenic children diagnosed with bacteremia between 2010 and 2014 were retrospectively reviewed. The causative bacteria and proportion of antibiotic-resistant bacteria were investigated and compared yearly during the study period. The clinical impact of antibiotic-resistant bacterial infections was also determined. RESULTS: A total of 336 bacteremia episodes were identified. During the entire study period, 181 (53.9%) and 155 (46.1%) episodes were caused by Gram-negative and Gram-positive bacteria, respectively. Viridans streptococci (25.9%), Klebsiella spp. (16.7%), and Escherichia coli (16.4%) were the most frequent causative bacteria. The overall distribution of causative bacteria was not significantly different annually. Antibiotic-resistant bacteria were identified in 85 (25.3%) episodes, and the proportion of antibiotic-resistant bacteria was not significantly different annually. Extended-spectrum β-lactamase-producing E. coli and Klebsiella spp. were most common among antibiotic-resistant Gram-negative bacteria, and they accounted for 30.6% (n = 34) of the identified E. coli and K. pneumoniae. Methicillin-resistant coagulase-negative staphylococci were most common among antibiotic-resistant Gram-positive bacteria, and it accounted for 88.5% (n = 23) of the identified coagulase-negative staphylococci. Antibiotic-resistant bacterial infections, especially antibiotic-resistant Gram-negative bacterial infections, caused significantly higher mortality due to bacteremia compared with non-antibiotic-resistant bacterial infections (P <0.001). CONCLUSION: Recently, Gram-negative bacteria caused more bacteremia cases than Gram-positive bacteria in febrile neutropenic children, and antibiotic-resistant Gram-negative bacterial infections increased. Antibiotic-resistant bacterial infections caused poorer prognosis compared with non-antibiotic-resistant bacterial infections, and therefore, continuous surveillance for changing epidemiology of antibiotic-resistant bacterial infections and their clinical impact is necessary.

Delayed Positional Vertigo after Stapes Surgery / 대한평형의학회지

Postoperative vertigo can occur after stapes surgery in approximately 5% of the patients, which more commonly presents immediately after surgery rather than in the delayed period. Isolated delayed vertigo after stapes surgery is commonly related to perilymphatic fistula. Herein we report a 36-year-old female patient who developed positional vertigo 18 days after stapes surgery demonstrating severe geotropic horizontal positional nystagmus on both sides during supine roll test. This patient was eventually diagnosed as the horizontal semicircular canal benign paroxysmal positional vertigo (BPPV) on the left side. This is a rare case of delayed vertigo following stapes surgery caused by BPPV rather than perilymphatic fistula.

Clinical Characteristics of Horizontal Canal Benign Paroxysmal Positional Vertigo with Persistent Geotropic Direction Changing Positional Nystagmus / 대한평형의학회지

OBJECTIVE: The purpose of this study was to identify the clinical characteristics of horizontal canal benign paroxysmal positional vertigo (h-BPPV) with persistent geotropic direction changing positional nystagmus (DCPN). METHODS: One hundred thirty two patients diagnosed as the geotropic subtype of h-BPPV were analyzed retrospectively. Patients were classified into two groups: persistent h-BPPV (ph-BPPV) group which means h-BPPV showing persistent (>1 minute) geotropic DCPN and short duration h-BPPV (sh-BPPV) group that means h-BPPV with short duration (< or =1 minute) geotropic DCPN. We compared the clinical characteristics and treatment outcomes between the two groups. RESULTS: The study included 34 patients with ph-BPPV and 98 patients with sh-BPPV. There were no differences between the two groups in age, distribution of sex and the affected side. The ph-BPPV group had higher secondary BPPV preponderance and dizziness handicap index (DHI) score compared to the sh-BPPV group. The ph-BPPV group required higher number of canalith repositioning procedures (CRPs) until resolution and higher multiple/single CRP ratio than the sh-BPPV group. In addition, the ph-BPPV group showed longer duration until the remission of subjective symptoms (vertigo, dizziness) compared to the sh-BPPV group. CONCLUSION: ph-BPPV was more frequently associated with secondary causes of BPPV and demonstrated higher DHI score, total number of CRP, and longer remission duration of subjective symptoms compared to sh-BPPV. This information may be helpful for clinicians in counseling and managing the patients with persistent geotropic DCPN h-BPPV.

Clinical Manifestations of Benign Paroxysmal Positional Vertigo after Head Trauma / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The purpose of this study was to identify the clinical characteristics of benign paroxysmal positional vertigo (BPPV) occurring after head trauma by comparing them to those of idiopathic BPPV (i-BPPV). SUBJECTS AND METHOD: We analyzed retrospectively 820 patients diagnosed with BPPV. Patients were classified into two groups: post-traumatic BPPV (t-BPPV) group and i-BPPV group. We compared the clinical characteristics (age, sex, affected side, duration of vertigo, types of BPPV) and treatment outcomes between the two groups. RESULTS: The study included 497 patients with i-BPPV and 56 patients with t-BPPV. There were no differences in age distribution and the affected side. The t-BPPV group had greater male preponderance (48%) than the i-BPPV group (24%) did and longer duration of vertigo compared to i-BPPV group (p=0.028). In addition, the t-BPPV group demonstrated higher horizontal canal BPPV/posterior canal BPPV ratio (t-BPPV vs. i-BPPV=0.54 vs. 0.20, p=0.008). Although the results of a single treatment outcome did not differ between the two groups (p=0.127), there was a greater tendency for the t-BPPV group to receive a higher number of therapeutic maneuvers until resolution than for the i-BPPV group (p=0.056). Recurrence rate also did not differ between the two groups (p=0.125). CONCLUSION: The clinical features did not differ significantly between the two groups, although t-BPPV demonstrated a tendency of low therapeutic efficacy and high recurrence rates compared to i-BPPV. This information may be helpful for clinicians in counseling and managing patients with t-BPPV.

Resveratrol Inhibits GABAC rho Receptor-Mediated Ion Currents Expressed in Xenopus Oocytes

Resveratrol is a phytoalexin found in grapes, red wine, and berries. Resveratrol has been known to have many beneficial health effects, such as anti-cancer, neuroprotective, anti-inflammatory, and life-prolonging effects. However, relatively little is known about the effects of resveratrol on the regulation of ligand-gated ion channels. We have previously reported that resveratrol regulates subsets of homomeric ligand-gated ion channels such as those of 5-HT3A receptors. The gamma-aminobutyric acidC (GABAC) receptor is mainly expressed in retinal bipolar cells and plays an important role in visual processing. In the present study, we examined the effects of resveratrol on the channel activity of homomeric GABAC receptor expressed in Xenopus oocytes injected with cRNA encoding human GABAC rho subunits. Our data show that the application of GABA elicits an inward peak current (IGABA) in oocytes that express the GABAC receptor. Resveratrol treatment had no effect on oocytes injected with H2O or with GABAC receptor cRNA. Co-treatment with resveratrol and GABA inhibited IGABA in oocytes with GABAC receptors. The inhibition of IGABA by resveratrol was in a reversible and concentration-dependent manner. The IC50 of resveratrol was 28.9+/-2.8 microM in oocytes expressing GABAC receptor. The inhibition of IGABA by resveratrol was in voltage-independent and non-competitive manner. These results indicate that resveratrol might regulate GABAC receptor expression and that this regulation might be one of the pharmacological actions of resveratrol on the nervous system.

Inhibitory Effects of Ginsenoside Metabolites, Compound K and Protopanaxatriol, on GABAC Receptor-Mediated Ion Currents

Ginsenosides, one of the active ingredients of Panax ginseng, show various pharmacological and physiological effects, and they are converted into compound K (CK) or protopanaxatriol (M4) by intestinal microorganisms. CK is a metabolite derived from protopanaxadiol (PD) ginsenosides, whereas M4 is a metabolite derived from protopanaxatriol (PT) ginsenosides. The gamma-aminobutyric acid receptorC (GABAC) is primarily expressed in retinal bipolar cells and several regions of the brain. However, little is known of the effects of ginsenoside metabolites on GABAC receptor channel activity. In the present study, we examined the effects of CK and M4 on the activity of human recombinant GABAC receptor (rho1) channels expressed in Xenopus oocytes by using a 2-electrode voltage clamp technique. In oocytes expressing GABAC receptor cRNA, we found that CK or M4 alone had no effect in oocytes. However, co-application of either CK or M4 with GABA inhibited the GABA-induced inward peak current (IGABA). Interestingly, pre-application of M4 inhibited IGABA more potently than CK in a dose-dependent and reversible manner. The half-inhibitory concentration (IC50) values of CK and M4 were 52.1+/-2.3 and 45.7+/-3.9 microM, respectively. Inhibition of IGABA by CK and M4 was voltage-independent and non-competitive. This study implies that ginsenoside metabolites may regulate GABAC receptor channel activity in the brain, including in the eyes.

3C8, a new monoclonal antibody directed against a follicular dendritic cell line, HK

BACKGROUND: Follicular dendritic cells (FDCs) play key roles during T cell-dependent humoral immune responses by allowing antigen-specific B cells to survive, proliferate, and differentiate within the FDC networks of secondary follicles, i.e., germinal centers (GC). METHODS: A novel monoclonal antibody, 3C8, was generated by immunizing with an FDC line HK, in order to understand the molecular signals involved in the FDC-B cell interactions in the microenvironment of the GC. RESULTS: The 3C8 antibody did not bind to mononuclear cells, including T cells, B cells, and monocytes. Murine L929 and human skin fibroblasts exhibited no or little reactivity to 3C8. However, 3C8 specifically recognized HK cells by flowcytometry. Furthermore, the antigen recognized by 3C8 was restricted to the GC of the human tonsil. Dendritic networks of the GC were intensely stained by 3C8, but cells out side the GC were not. CONCLUSION: Our result s suggest that the antigen 3C8 may play some unique role on FDCs during the GC reactions.

Clinical Significance of the Colorectal Polyps

The aim of this study was to investigate the association of colorectal polyps with carcinoma of the colon and rectum. METHODS: Between January 1995 and December 1998, 203 consecutive patients with 423 colorectal polyps retrospectively documented at the Department of General Surgery and College of Medicine in Dongguk University. RESULTS: The peak age group of the colorectal polyp was in the fifth decades (33.5%). The proportions of malignant polyps were as follows: for size, 5.2% of polyps less than 1.0 cm and 19.5% of polyps larger than 1 cm (P0.05); for number of polyp, 4.5% in cases of single polyp and 25.0% in cases of multiple polyps (P<0.05); for underlying histology, 9.2% in cases of tubular adenoma and 19.2% in cases of villous adenoma (p<0.05). The presence of distal adenomatous polyp was increased the risk of presence of the proximal adenomas (59.7%), whereas the presence of hyperplastic polyp did not (16.7%). CONCLUSIONS: The malignant potential of colorectal polyps are correlated with size, histologic type, morphologic shape, multiplicity and distal location. The presence of hyperpalstic polyp should not be indication for colonoscopy because they are not associated with proximal adenoma when adjusting for patient characteristics and presence of distal adenoma.