Ethnic and sex differences in the distributions of body mass index and waist circumference among adults: a binationally representative study in South Korea and the United States.

OBJECTIVE: The ethnic and sex differences in the distributions of body mass index (BMI) and waist circumference (WC) among adults are largely unknown. Therefore, we aimed to investigate the percentiles of BMI and WC in groups divided according to age, sex, and ethnicity. PATIENTS AND METHODS: We conducted a population-based binational study of adults aged ≥20 years based on data from two sources: US National Health and Nutrition Examination Survey (2015 to 2020) and Korea National Health and Nutrition Examination Survey (2016 to 2019). RESULTS: Weight, height, and WC were measured in 13,144 American adults and 30,191 Korean adults. Overall, BMI increased at younger ages and decreased at older ages, which indicates a reversed U-shaped relationship, and differed in terms of age, sex, and ethnicity. Women in the other Hispanic, non-Hispanic white, non-Hispanic black, and "other ethnic groups" showed a common BMI peak at ages 50-54 years. The patterns of WC distribution were similar to those of BMI distribution. CONCLUSIONS: In this binational representative study, we found varied distributions of ethnic and sex differences in BMI and WC. Considering the differences in these distributions may help improve individual and personalized treatment strategies.

Female reproductive factors and risk of joint replacement arthroplasty of the knee and hip due to osteoarthritis in postmenopausal women: a nationwide cohort study of 1.13 million women.

OBJECTIVES: Previous studies of the relationships between female reproductive factors and osteoarthritis (OA) have shown conflicting results. In this study, we aimed to explore the relationships between reproductive factors and joint replacement arthroplasty of the knee (TKRA) and hip (THRA) in a large nationwide population-based cohort of postmenopausal Korean women. METHODS: We included 1,134,680 subjects who participated in national health examinations in 2009 in the study. The study outcomes were incident THRA or TKRA due to severe hip or knee OA. The relationships between reproductive factors and THRA or TKRA were evaluated using a multivariable-adjusted proportional hazards model. RESULTS: During a mean follow-up duration of 8.2 years, 1,610 incident THRA cases and 60,670 incident TKRA cases were observed. Later age at menarche, longer breastfeeding, HRT and OC use were associated with increased risk of TKRA for severe knee OA, while later age at menopause and longer reproductive span were associated with decreased risk. With regard to THRA for severe hip OA, later menarche, longer breastfeeding, HRT more than 5 years, and OC use more than 1 year were associated with higher risk. The associations between reproductive factors and severe OA were more pronounced in underweight and younger subjects. CONCLUSION: We found that shorter estrogen exposure was associated with higher risk of TKRA due to severe knee OA, and such associations were more pronounced in underweight and younger subjects. The association between shorter estrogen exposure and THRA was not robust.

Three-percent sucrose acts as a thermostabilizer for cell-adapted foot-and-mouth disease virus without any negative effect on viral growth.

AIMS: As cell-adapted foot-and-mouth disease virus (FMDV) with H56R mutation in VP3 has reduced thermostability, this study aimed to investigate the effect of thermostabilizers on cell-adapted FMDV for vaccine production. METHODS AND RESULTS: We examined the effect of 3% sucrose, 10% (or 25%) glycerol or 10% FBS on cell-adapted FMDV O/SKR/JC/2014, containing H56R mutation in VP3, as vaccine seed virus at -80, 4, 25 or 37°C for 2, 4 or 7 days. The stabilizing effect of 3% sucrose on O/SKR/JC/2014 was observed at 25, 37°C, and after repeated freeze-thaw cycles. Additionally, we tested the effect of 3% sucrose on the growth of FMDV or cells and did not observe any decrease in either viral growth or cell viability. CONCLUSIONS: Our study showed the protective effect of 3% sucrose on FMDV infectivity at various temperatures; this virus stock in 3% sucrose could be used for infecting cells without the removal of sucrose. SIGNIFICANCE AND IMPACT OF THE STUDY: We suggest that 3% sucrose-containing medium could be beneficial for the stable storage and transport of cell-adapted FMDV.

Efficacy of a high quality O1/Campos foot-and-mouth disease vaccine upon challenge with a heterologous Korean O Mya98 lineage virus in pigs.

In 2010 serotype O foot-and-mouth disease virus of the Mya98 lineage/SEA topotype spread into most East Asian countries. During 2010-2011 it was responsible for major outbreaks in the Republic of Korea where a monovalent O/Manisa vaccine (belonging to the ME-SA topotype) was applied to help control the outbreaks. Subsequently, all susceptible animals were vaccinated every 6 months with a vaccine containing the O/Manisa antigen. Despite vaccination, the disease re-occurred in 2014 and afterwards almost annually. This study focuses on the in vivo efficacy in pigs of a high quality monovalent commercial O1/Campos vaccine against heterologous challenge with a representative 2015 isolate from the Jincheon Province of the Republic of Korea. Initially, viral characterizations and r1 determinations were performed on six viruses recovered in that region during 2014-2015, centering on their relationship with the well characterized and widely available O1/Campos vaccine strain. Genetic and antigenic analysis indicated a close similarity among 2014-2015 Korean isolates and with the previous 2010 virus, with distinct differences with the O1/Campos strain. Virus neutralisation tests using O1/Campos cattle and pig post vaccination sera and recent Korean outbreak viruses predicted acceptable cross-protection after a single vaccination, as indicated by r1 values, and in pigs, by expectancy of protection. In agreement with the in vitro estimates, in vivo challenge with a selected field isolate indicated that O1/Campos primo vaccinated pigs were protected, resulting in a PD50 value of nearly 10. The results indicated that good quality oil vaccines containing the O1/Campos strain can successfully be used against isolates belonging to the O Mya98/SEA topotype.

COUP-TFII Stimulates Dentin Sialophosphoprotein Expression and Mineralization in Odontoblasts.

Chicken ovalbumin upstream promoter transcription factor 2 (COUP-TFII), an orphan nuclear receptor belonging to the steroid-thyroid hormone receptor superfamily, plays an important role in cell fate determination of various tissues. However, the specific role of COUP-TFII in tooth development has not yet been elucidated. In the present study, we aimed to explore the role of COUP-TFII in dentin sialophosphoprotein (DSPP) expression and matrix mineralization in odontoblast-lineage cells. In primary human dental pulp cells (HDPCs) and murine dental papilla-derived cells (MDPC-23) cultured in a mineralizing medium, the expression of COUP-TFII was induced along with the increased odontoblast-specific dentin matrix protein-1 (DMP-1) and DSPP expression. Endogenous expression of COUP-TFII in maxillary second molar germs of rats showed an increasing tendency as development of the tooth progressed. Also, COUP-TFII protein was detected in greater quantity in the odontoblastic layer of second molar germs than in that of third molar germs of rats. Overexpression of COUP-TFII using an adenoviral system upregulated the expression of odontoblast-specific genes with increased alkaline phosphatase activity and matrix mineralization in odontoblast-lineage cells. In contrast, knockdown of COUP-TFII using small interfering RNA decreased the expression of odontoblast-specific genes, which reduced matrix mineralization. Mechanistic studies revealed that COUP-TFII increased DSPP transcription by direct binding on the DSPP promoter. In addition, COUP-TFII physically interacted with the homeodomain transcription factor Msx2 and antagonistically regulated the Msx2 effect on DSPP promoter activity. Taken together, these results suggest that COUP-TFII has a stimulatory role in DSPP expression and matrix mineralization in odontoblast-lineage cells.

Outbreaks and diagnosis of foot-and-mouth disease serotype O in the Republic of Korea, April-June 2010.

Thirteen outbreaks of foot-and-mouth disease (FMD) were reported in pigs and cattle in Korea between 8 April and 4 June 2010. The FMD virus (FMDV) isolates were of serotype O, indicating that they were related to the virus strains of the Southeast Asia topotype that are circulating in East Asian countries. Animals carrying the viruses were identified by reverse transcriptase-polymerase chain reaction (RT-PCR) during a 29-day period between 8 April and 6 May, 2010. Prior to this outbreak, these FMDVs had not been detected in Korea and may therefore have been introduced from neighbouring countries into Ganghwa Island and subsequently spread inland to other areas, including Gimpo, Chungju and Cheongyang. Tests conducted to lift restrictions on animal movements lead to detection of two additional FMD-positive farms. Through appropriate responses, including swift diagnoses and culling policies, Korea was able to quickly regain its recognition as being free of FMD, without vaccination, by the World Organization for Animal Health (OIE) on 27 September 2010.

Environmental lung diseases: clinical and imaging findings.

Environmental lung diseases are caused by exposure to adverse environmental conditions, such as atmospheric pressure changes or the ingestion or inhalation of toxic agents. The development of environmental lung diseases depends on the intensity and duration of exposure, the physiological and biological susceptibility of the host, and the toxic effects of the adverse environmental conditions encountered. A combination of clinical features, related exposure history, imaging findings, and a review of previous reports that support an association between exposure and the disease process is required for diagnosis.

Diagnosis and control measures of the 2010 outbreak of foot-and-mouth disease A type in the Republic of Korea.

In January 2010, foot-and-mouth disease (FMD) occurred for the first time in 8 years in Korea. The outbreaks were because of A serotype, different from the O type, which had occurred previously in 2000 and 2002. The FMD outbreaks were identified in seven farms, consisting of six cattle farms where viruses were detected and one deer farm where only FMDV antibody was detected. The seven farms were within 9.3 km of each other. All susceptible animals within 10 km radius of the outbreak farms were placed under movement restrictions for 3-11 weeks. No vaccination took place to facilitate the clinical observation of infected animals and virus detection. After clinical observations and serological tests within the control zones showed no evidence of FMD infection, the movement restrictions were lifted, followed by FMD-free declaration (23 March) at 80 days after the first outbreak on 2 January. This communication describes the outbreak of FMD A serotype, and control measures applied to eradicate the disease in Korea.

SHP is involved in BMP2-induced odontoblast differentiation.

Small Heterodimer Partner (SHP) interacts with diverse transcription factors such as Runx2 and regulates many cellular events including differentiation, proliferation, and energy metabolism. SHP is reported to be a positive regulator of BMP2-induced bone formation. This study aimed to clarify the role of SHP in odontoblast differentiation and matrix mineralization. Rat tooth germs were isolated, and gene expression was determined by RT-PCR and real-time PCR. Localization of SHP protein expression was identified by immunofluorescent analysis. Primary human dental pulp cells (HDPCs) were cultured with BMP2 and/or Ad-siSHP. Matrix mineralization was evaluated by Alizarin red staining. Transient transfection experiment was performed with the SHP or Dlx5 expressional plasmids and the DSPP gene. In tooth germs from post-natal days 3 to 9, BMP-2 and SHP expression increased with DSPP and DMP1 mRNA expression. In an immunostaining study, SHP was expressed in odontoblasts and surrounding osteoblasts. When HDPCs were cultured with BMP2 in mineralization-inducing medium, SHP expression also increased with an increase in DSPP expression. Down-regulation of SHP by Ad-siSHP inhibited matrix mineralization. In transient transfection experiments, overexpression of SHP was shown to enhance DSPP promoter activity through interactions between SHP and Dlx5. These results suggest that SHP may mediate BMP2 signaling to promote mineralization of the dentin matrix.

Carbohydrate but not fat is associated with elevated aminotransferases.

BACKGROUND: Recently, many studies reported that high carbohydrate and simple sugar intake increase a risk of obesity and metabolic syndrome significantly. AIM: To investigate the effect of carbohydrate on aminotransferase levels in Korea, where the proportion of carbohydrate in meals is extremely high but fat is low. METHODS: We used the data of Korean National Health and Nutrition Examination Surveys (KNHANES). A total of 19 749 people were included. Amounts and types of consumed foods were examined by the 24 h recall method. RESULTS: Mean carbohydrate and fat proportions in total energy intake were 67.7% and 17.4%, respectively. Aminotransferase activity increased according to the rise of the proportion of carbohydrate in the energy intake. A high carbohydrate intake (>70% of energy) was associated with abnormal aminotransferase activity and metabolic syndrome. After adjusting for covariates, such as age, energy intake and body mass index, abnormal aminotransferase activity was significantly associated with carbohydrate proportion. There was a negative correlation between fat proportion in the total energy intake and aminotransferase activity (P < 0.01). The relation between aminotransferase activity and carbohydrate composition showed a J-shaped curve. The lowest point (the J point) was located at 50-60% carbohydrate. CONCLUSIONS: The proportion of carbohydrate in energy intake but not fat is positively correlated with abnormal aminotransferase activity in Koreans. This finding may be useful in planning a strategy of nutrition education for NAFLD in countries where the proportion of carbohydrate in most meals is extremely high.

Hounsfield units upon PET/CT are useful in evaluating metastatic regional lymph nodes in patients with oesophageal squamous cell carcinoma.

OBJECTIVES: This study evaluated the usefulness of measurements of X-ray attenuation (in Hounsfield units) obtained from unenhanced CT images for attenuation correction of the positron emission tomography (PET) data from PET/CT in the assessment of regional lymph node metastasis in oesophageal squamous cell carcinoma. METHODS: 17 patients with oesophageal squamous cell carcinoma underwent surgery after evaluation with PET/CT. After the excised lymph nodes were reviewed, we compared the histopathology and PET/CT findings, and analysed the lymph node metastasis. When 18-F fludeoxyglucose (FDG) uptake in the lymph nodes was focally prominent in comparison with background mediastinal activity (regardless of lymph node size), the lymph nodes were considered to be positive for malignancy by PET/CT. The mean Hounsfield units of mediastinal lymph nodes showing abnormally increased FDG uptake in PET/CT was retrospectively evaluated using images from the unenhanced CT component of PET/CT. Receiver operating characteristic (ROC) curve analysis was applied to determine the optimal cut-off value of mean Hounsfield units for detecting individual lymph node metastases. RESULTS: For depiction of malignant nodal groups in each lymph node group, the sensitivity, specificity and accuracy of PET/CT based on increased FDG uptake were 58.8%, 74.5% and 70.8%, respectively. For patients with nodal groups that were positive for uptake by PET/CT, the mean attenuation in lymph nodes as measured by CT was 48 ± 13 HU for malignant nodes and 75 ± 18 HU for benign nodes. This difference was statistically significant (p<0.001). Using ROC curve analysis, we determined the cut-off as 71 HU. When we excluded lymph nodes with attenuation higher than 71 HU from the nodes determined as malignant by PET/CT, the specificity and accuracy for detecting metastatic lymph nodes improved to 90.9% and 83.3%, respectively. CONCLUSIONS: When interpreting lymph node metastasis in oesophageal squamous cell carcinoma using PET/CT, the assumption that any lymph node with mean HU>71 is benign can improve diagnostic accuracy.

Formulation, pharmacokinetics and biodistribution of Ofloxacin-loaded albumin microparticles and nanoparticles.

Albumin microparticles containing Ofloxacin (Fluoroquinolone derivative commonly used in hospitals) were formulated by the spray dry method. By decreasing the pump feed rate or the total polymer concentration, a mixture of albumin/hypromellose acetate succinate (HPMCAS) microparticles and nanoparticles (MP/NP), containing Ofloxacin, were formulated. MP/NP were characterized, in vitro (particle size, zeta potential, and encapsulation efficiency). A comparison of the pharmacokinetics and biodistribution of aqueous Ofloxacin and Ofloxacin-loaded MP/NP, in Balb/c mice, revealed that peak concentrations were reduced in the serum, liver, spleen and brain, and a more sustained release was observed in serum and all of the organs tested for Ofloxacin MP/NP, compared to aqueous Ofloxacin. The MP/NP formulation allowed extended release by 24 h in the liver and more than 48 h in the brain. In serum, the elimination rate of Ofloxacin MP/NP is slower, the half life is longer, area under the plasma concentration time curve is decreased and volume of distribution is increased.

Evaluation of the nucleated red blood cell count in neonates using the Beckman Coulter UniCel DxH 800 analyzer.

INTRODUCTION: Nucleated red blood cell (NRBC) count is closely associated with the prognosis of neonates. The analysis of NRBC has traditionally been measured manually. Recently, a newly developed automated hematology analyzer, the UniCel DxH 800 (DxH 800), was released. The goal of our study was to evaluate the performance of the DxH 800 NRBC method in neonates with the reference manual method and against previous generation hematology analyzers. METHODS: NRBCs were counted in 162 neonatal blood samples using the DxH 800, LH 750, and ADVIA 2120 vs. the reference manual technique. The concordance rate, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were obtained. RESULTS: The DxH 800 showed an R(2) value of 0.945 and the concordance rate of 93.8%. Further assessment revealed 85.3% sensitivity, 96.1% specificity, 85.3% PPV, and 96.1% NPV, resulting in the highest area under the curve (0.961). The LH 750 and ADIVA 2120 demonstrated R(2) values of 0.851 and 0.529, respectively. CONCLUSION: The results obtained indicate the UniCel DxH 800 to be an excellent test on neonatal blood and superior to the other analyzers. Therefore, the DxH 800 is an effective and highly sensitive system for the analysis of NRBCs on newborns.

Enhancement of fibrinolysis by inhibiting enzymatic cleavage of precursor α2-antiplasmin.

BACKGROUND AND OBJECTIVE: Resistance of thrombi to plasmin digestion depends primarily on the amount of α(2)-antiplasmin (α(2)AP) incorporated within fibrin. Circulating prolyl-specific serine proteinase, antiplasmin-cleaving enzyme (APCE), a homologue of fibroblast activation protein (FAP), cleaves precursor Met-α(2)AP between -Pro12-Asn13- to yield Asn-α(2)AP, which is crosslinked to fibrin approximately 13× more rapidly than Met-α(2)AP and confers resistance to plasmin. We reasoned that an APCE inhibitor might decrease conversion of Met-α(2)AP to Asn-α(2)AP and thereby enhance endogenous fibrinolysis. METHODS AND RESULTS: We designed and synthesized several APCE inhibitors and assessed each vs. plasma dipeptidyl peptidase IV (DPPIV) and prolyl oligopeptidase (POP), which have amino acid sequence similarity with APCE. Acetyl-Arg-(8-amino-3,6-dioxaoctanoic acid)-D-Ala-L-boroPro selectively inhibited APCE vs. DPPIV, with an apparent K(i) of 5.7 nm vs. 6.1 µm, indicating that an approximately 1000-fold greater inhibitor concentration is required for DPPIV than for APCE. An apparent K(i) of 7.4 nm was found for POP inhibition, which is similar to 5.7 nm for APCE; however, the potential problem of overlapping FAP/APCE and POP inhibition was negated by our finding that normal human plasma lacks POP activity. The inhibitor construct caused a dose-dependent decrease of APCE-mediated Met-α(2)AP cleavage, which ultimately shortened plasminogen activator-induced plasma clot lysis times. Incubation of the inhibitor with human plasma for 22 h did not lessen its APCE inhibitory activity, with its IC(50) value in plasma remaining comparable to that in phosphate buffer. CONCLUSION: These data establish that inhibition of APCE might represent a therapeutic approach for enhancing thrombolytic activity.

Lactone form 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins) stimulate the osteoblastic differentiation of mouse periodontal ligament cells via the ERK pathway.

BACKGROUND AND OBJECTIVE: Recent studies reported that the lactone forms of 3-hydroxy- 3-methylglutaryl-coenzyme A reductase inhibitors, which are also known as statins, have a bone stimulatory effect. However, there are few reports on the effect of statins on periodontal ligament cells. This study examined the statin-induced osteoblastic differentiation of mouse periodontal ligament cells as well as its mechanism. MATERIAL AND METHODS: Mouse periodontal ligament cells were cultured with lovastatin or simvastatin, and their viability was measured. The levels of alkaline phosphatase (ALP), osteocalcin, bone sialoprotein and bone morphogenetic protein-2 mRNA expression were evaluated by RT-PCR. The osteoblastic differentiation was characterized by the ALP activity and Alizarin Red-S staining for calcium deposition. The activity of the osteocalcin gene (OG2) and synthetic osteoblast-specific elements (6× OSE) promoter with statins was also measured using a luciferase assay. For the signal mechanism of statins, the ERK1/2 MAPK activity was determined by western blot analysis. RESULTS: A statin treatment at concentrations < 1 µM did not affect the cell viability. Lovastatin or simvastatin at 0.1 µM increased the levels of ALP, osteocalcin, bone sialoprotein and bone morphogenetic protein-2 mRNA in mouse periodontal ligament cells. In addition, the ALP activity, mineralized nodule formation and OG2 and OSE promoter activity were higher in the lovastatin- or simvastatin-treated cells than the control cells. Western blot analysis confirmed that the statins stimulated the phosphorylation of ERK1/2. CONCLUSION: Lovastatin and simvastatin may stimulate the osteoblastic differentiation of periodontal ligament cells via the ERK1/2 pathway. This suggests that the statins may be useful for regenerating periodontal hard tissue.

Evidence that alpha2-antiplasmin becomes covalently ligated to plasma fibrinogen in the circulation: a new role for plasma factor XIII in fibrinolysis regulation.

BACKGROUND: Plasma alpha2-antiplasmin (alpha2AP) is a rapid and effective inhibitor of the fibrinolytic enzyme plasmin. Congenital alpha2AP deficiency results in a severe hemorrhagic disorder due to accelerated fibrinolysis. It is well established that in the presence of thrombin-activated factor XIII (FXIIIa), alpha2AP becomes covalently ligated to the distal alpha chains of fibrin or fibrinogen at lysine 303 (two potential sites per molecule). Some time ago we showed that alpha2AP is covalently linked to plasma fibrinogen . That singular observation led to our hypothesis that native plasma factor XIII (FXIII), which is known to catalyze covalent cross-linking of fibrinogen in the presence of calcium ions, can also incorporate alpha2AP into fibrinogen in the circulation. RESULTS AND CONCLUSIONS: We now provide evidence that FXIII incorporates I 125-labelled alpha2AP into the Aalpha-chain sites on fibrinogen or fibrin. We also measured the content of alpha2AP in isolated plasma fibrinogen fractions by ELISA and found that substantial amounts were present (1.2-1.8 moles per mole fibrinogen). We propose that alpha2AP becomes ligated to fibrinogen while in the circulation through the action of FXIII, and that its immediate presence in plasma fibrinogen contributes to regulation of in vivo fibrinolysis.

Pathogenic characteristics of the Korean 2002 isolate of foot-and-mouth disease virus serotype O in pigs and cattle.

Experimental infection of susceptible cattle and pigs showed that the O/SKR/AS/2002 pig strain of foot-and-mouth disease virus (FMDV) causes an infection that is highly virulent and contagious in pigs but very limited in cattle. Pigs directly inoculated with, or exposed to swine infected with, strain O/SKR/AS/2002 showed typical clinical signs, including gross vesicular lesions in mouth and pedal sites. In addition, FMDV was isolated from, and FMDV genomic RNA was detected in, blood, serum, nasal swabs and oesophageal-pharyngeal (OP) fluid early in the course of infection. Antibodies against the non-structural protein (NSP) 3ABC were detected in both directly inoculated and contact pigs, indicating active virus replication. In contrast, the disease in cattle was atypical. After inoculation, lesions were confined to the infection site. A transient viraemia occurred 1 and 2 days after inoculation, and this was followed by the production of antibodies to NSP 3ABC, indicating subclinical infection. No clinical disease was seen, and no antibodies to NSP 3ABC were present in contact cattle. Additionally, no virus or viral nucleic acid was detected in blood, nasal swab and OP fluid samples from contact cattle. Thus, the virus appeared not to be transmitted from infected cattle to contact cattle. In its behaviour in pigs and cattle, strain O/SKR/AS/2002 resembled the porcinophilic FMDV strain of Cathay origin, O/TAW/97. However, the latter, unlike O/SKR/AS/2002, has reduced ability to grow in bovine-derived cells. The porcinophilic character of O/TAW/97 has been attributed to a deletion in the 3A coding region of the viral genome. However, O/SKR/AS/2002 has an intact 3A coding region.

Why alpha-antiplasmin must be converted to a derivative form for optimal function.

BACKGROUND: Human alpha(2)-antiplasmin (alpha(2)AP), the primary inhibitor of fibrinolysis, is secreted from the liver into plasma as a 464-residue protein with Met as the N-terminus. An R6W polymorphism has been suggested to affect fibrinolytic rate. Within circulating blood, antiplasmin-cleaving enzyme (APCE) cleaves Met-alpha(2)AP(R6) faster than Met-alpha(2)AP(W6) at the Pro12-Asn13 bond to yield Asn-alpha(2)AP. OBJECTIVES: To compare Met-alpha(2)AP(R6), Met-alpha(2)AP(W6) and Asn-alpha(2)AP for crosslinking with fibrin and the ability to protect fibrin from digestion by plasmin. METHODS AND RESULTS: Asn-alpha(2)AP utilizes Gln2 (Gln14 in Met-alpha(2)AP) to become crosslinked to fibrin approximately twelvefold faster than Met-alpha(2)AP(R6) or Met-alpha(2)AP(W6), and this enhances the resistance of fibrin to plasmin. All three forms of alpha(2)AP inhibit plasmin at identical rates. The N-terminal 12-residue peptide of Met-alpha(2)AP slows crosslinking of Met-alpha(2)AP(R6) or Met-alpha(2)AP(W6) by limiting access of factor XIIIa to Gln14 rather than shifting crosslinking to other Gln residues. Edman sequencing and mass analyses of tryptic peptides from each alpha(2)AP crosslinked with 5-(biotinamido)pentylamine showed Gln14 as the only major crosslinking site. Residues 5-8, GRQL in Met-alpha(2)AP(R6), and residues 1-8, MEPLGWQL in Met-alpha(2)AP(W6), slow fibrin crosslinking. CONCLUSION: Gln14 in both Met-alpha(2)AP(R6) and Met-alpha(2)AP(W6) is sheltered by the N-terminal 12-residue peptide, which, when cleaved, yields Asn-alpha(2)AP, which is rapidly crosslinked to fibrin and maximally protects it from plasmin. The R6 W polymorphism in Met-alpha(2)AP does not affect its crosslinking to fibrin, but it does slow cleavage by APCE and reduces the amount of Asn-alpha(2)AP available for rapid crosslinking to fibrin.