Randomized trial of contrast-enhanced harmonic guidance versus fanning technique for EUS-guided fine-needle biopsy sampling of solid pancreatic lesions.

BACKGROUND AND AIMS: For EUS-guided fine-needle biopsy sampling (EUS-FNB) of solid pancreatic lesions (SPLs), the role of sampling strategy between targeted biopsy sampling and wide sampling has not been reported. This study aimed to investigate the benefits of the 2 sampling techniques on EUS-FNB using rapid on-site evaluation. METHODS: Patients with SPLs were prospectively enrolled and randomly assigned (1:1) to undergo EUS-FNB using either contrast guidance or the fanning technique. The primary outcome was the total number of passes required to establish a diagnosis, and secondary outcomes were overall diagnostic accuracy and adverse event rates. RESULTS: One hundred eighteen patients were enrolled from February 2019 to January 2021, with 59 patients assigned to each group. There was no significant difference in the total number of passes required to establish a diagnosis between the contrast and fanning groups (median, 1 [interquartile range, 1-1] vs 1 [interquartile range, 1-2], respectively; P = .629). The sensitivity, specificity, and diagnostic accuracy in the contrast group was 100%, 66.7%, and 98.3% and in the fanning group 100%, 100%, and 100%, respectively (P = 1). An SPL <4 cm (odds ratio, 2.47; 95% confidence interval, 1.05-5.81; P = .037) and macroscopic visible core length >1 cm (odds ratio, 2.89; 95% confidence interval, 1.07-7.84; P = .037) were independently associated with increased cytologic and histologic accuracy. CONCLUSIONS: The diagnostic accuracy of EUS-FNB with the fanning technique for SPLs was comparable with the contrast guidance technique. Without additional cost, EUS-FNB with the fanning technique may be preferred for SPLs. (Clinical trial registration number: NCT04924725.).

Detrimental effects of fresh frozen plasma transfusions on postoperative outcomes in patients undergoing liver resection for hepatocellular carcinoma.

BACKGROUND: Perioperative fresh frozen plasma (FFP) is commonly transfused to patients undergoing liver resection for hepatocellular carcinoma (HCC), but its impacts in this population remain unknown. This study aimed to investigate the association of perioperative FFP transfusion with short-term and long-term outcomes in these patients. METHODS: We retrospectively identified and retrieved clinical data for HCC patients undergoing liver resection between March, 2007 and December, 2016. Study outcomes included postoperative bacterial infection, extended length of stay (LOS) and survival. Propensity score (PS) matching was used to determine the association of FFP transfusion with each outcome. RESULTS: A total of 1427 patients were included, and 245 of them received perioperative FFP transfusions (17.2%). Patients received perioperative FFP transfusions were older, underwent liver resection in the earlier time period, and had more extensive resection, poorer clinical conditions, and higher proportions of receiving other blood components. Perioperative FFP transfusion was associated with higher odds of both postoperative bacterial infection (OR = 1.77, p = 0.020) and extended LOS (OR = 1.93, p=<0.001), and the results remained similar after PS-matching. However, perioperative FFP transfusion did not significantly affect survival in these patients (HR = 1.17, p = 0.185). A potential association of postoperative FFP transfusions and poorer 5-year but not overall survival was observed in a subgroup of patients with low postoperative albumin levels after PS-matching. CONCLUSION: Perioperative FFP transfusions were associated with poorer short-term postoperative outcomes in HCC patients undergoing liver resection, including postoperative bacterial infection and extended LOS. Reducing perioperative FFP transfusions has the potential to improve their postoperative outcomes.

Using Ion Torrent sequencing to study genetic mutation profiles of fatal thyroid cancers.

BACKGROUND/PURPOSE: Surgery followed by radioiodine is a mainstay of treatment for thyroid cancers of follicular origins. However, about 5% of the thyroid cancers are non-operable and/or radioiodine-refractory diseases, which are either locally advanced or metastatic and result in a survival of less than 5 years. How to treat this population of thyroid cancer patients becomes a critical issue requiring further understanding of the tumor's genetic information. METHODS: We used formalin-fixed paraffin-embedded specimens of 22 fatal thyroid cancers and their corresponding non-tumor parts, if available, to yield genomic DNA, and applied the Ion Torrent™ Personal Genome Machine (IT-PGM) System (Life Technologies), a next generation sequencing technology, to interrogate 740 mutational hotspots in 46 oncogenes. We further validated the results by conventional direct sequencing. RESULTS: We confirmed 21 mutations of 11 oncogenes in the 22 fatal thyroid cancer samples. Among them, the MET p.N375S and MLH1 p.V384D mutations, each was detected in two cases, and has rarely been found to be involved in thyroid cancer pathogenesis before. We also identified homozygous PDGFRA p.V824V mutation in eight out of the 22 cases, while the non-tumor counterparts carried heterozygous PDGFRA p.V824V mutation. We noted that the Ion Torrent technique unfortunately showed high false positive rates for detecting EGFR mutations in thyroid cancers. CONCLUSION: The extensive genetic studies provide new insights to future targeted therapy in these patients. IT-PGM proved to be valuable for comprehensively searching genetic mutations in potentially fatal thyroid cancers.

Evaluation of the Bruker Biotyper matrix-assisted laser desorption ionization-time of flight mass spectrometry system for identification of blood isolates of Vibrio species.

Among 56 blood isolates of Vibrio species identified by sequencing analysis of 16S rRNA and rpoB genes, the Bruker Biotyper matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) system correctly identified all isolates of Vibrio vulnificus (n = 20), V. parahaemolyticus (n = 2), and V. fluvialis (n = 1) but none of the isolates of serogroup non-O1/O139 (non-serogroup O1, non-O139) V. cholerae (n = 33) to the species level. All of these serogroup non-O1/O139 V. cholerae isolates were correctly identified using the newly created MALDI-TOF MS database.

Effects of high-dose phytoestrogens on circulating cellular microparticles and coagulation function in postmenopausal women.

BACKGROUND/PURPOSE: Estrogen in hormone replacement therapy causes homeostatic changes. However, little is known regarding the safety of high-dose phytoestrogen on coagulation and hematological parameters in healthy postmenopausal women. This study evaluated the effects of high-dose soy isoflavone (300 mg/day) on blood pressure, hematological parameters, and coagulation functions including circulating microparticles in healthy postmenopausal women. METHODS: The original study is a 2-year prospective, double-blind, placebo-controlled study. In total, 431 postmenopausal women (from 3 medical centers) were randomly assigned to receive either high-dose isoflavone or placebo for 2 years. At baseline, 6 months, 1 year, and 2 years after treatment, blood pressure, body weight, liver function tests, hematological parameters, and lipid profiles were measured. The 1(st) year blood specimens of 85 cases of 144 eligible participants (from one of the three centers) were analyzed as D-dimer, von Willebrand factor antigen, factor VII, plasminogen activator inhibitor type 1, and circulating cellular microparticles, including the measurement of monocyte, platelet, and endothelial microparticles. RESULTS: In the isoflavone group, after 1 year, the changes in liver function tests, hematological parameters, and coagulation tests were not different from those of the control. Triglyceride levels were significantly lower after 6 months of isoflavone treatment than the placebo group, but the difference did not persist after 1 year. Endothelial microparticles increased steadily in both groups during the 1-year period but the trend was not affected by treatment. CONCLUSION: The results of the present study indicate that high-dose isoflavone treatment (300 mg/day) does not cause hematological abnormalities or activate coagulation factors.

Tuberculosis mortality: patient characteristics and causes.

BACKGROUND: In the antibiotic era, tuberculosis (TB) still causes a substantial number of mortalities. We aimed to identify the causes and risks of death among TB patients. METHODS: Medical records of mortality cases of culture-proven TB diagnosed during 2003-2007 were reviewed. All TB deaths were classified into 2 groups (TB-related and non-TB-related), based on the underlying cause of death. RESULTS: During the study period, 2016 cases (male: 71.1%) of culture-proven TB were identified. The mean age was 59.3 (range: 0.3-96) years. The overall mortality rate was 12.3% (249 cases) and the mean age at death was 74 years; 17.3% (43 cases) of all TB deaths were TB-related. Most of the TB-related deaths occurred early (median survival: 20 days), and the patient died of septic shock. Malignancy, liver cirrhosis, renal failure, and miliary and pneumonic radiographic patterns were all independent predictors for all TB deaths. Cavitary, miliary and pneumonic radiographic patterns were all significant predictive factors for TB-related death. Extrapulmonary involvement and liver cirrhosis were also factors contributing to TB-related death. CONCLUSIONS: The majority of TB deaths were ascribed to non-TB-related causes. Managing TB as well as underlying comorbidities in a multidisciplinary approach is essential to improve the outcome of patients in an aging population. However, the clinical manifestations of patients with TB-related death vary; many progressed to fulminant septic shock requiring timely recognition with prompt treatment to prevent early death.

Uracil-DNA Glycosylase Assay by Matrix-assisted Laser Desorption/Ionization Time-of-flight Mass Spectrometry Analysis.

Uracil-DNA glycosylase (UDG) is a key component in the base excision repair pathway for the correction of uracil formed from hydrolytic deamination of cytosine. Thus, it is crucial for genome integrity maintenance. A highly specific, non-labeled, non-radio-isotopic method was developed to measure UDG activity. A synthetic DNA duplex containing a site-specific uracil was cleaved by UDG and then subjected to Matrix-assisted Laser Desorption/Ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis. A protocol was established to preserve the apurinic/apyrimidinic site (AP) product in DNA without strand break. The change in the m/z value from the substrate to the product was used to evaluate uracil hydrolysis by UDG. A G:U substrate was used for UDG kinetic analysis yielding the Km = 50 nM, Vmax = 0.98 nM/s, and Kcat = 9.31 s-1. Application of this method to a uracil glycosylase inhibitor (UGI) assay yielded an IC50 value of 7.6 pM. The UDG specificity using uracil at various positions within single-stranded and double-stranded DNA substrates demonstrated different cleavage efficiencies. Thus, this simple, rapid, and versatile MALDI-TOF MS method could be an excellent reference method for various monofunctional DNA glycosylases. It also has the potential as a tool for DNA glycosylase inhibitor screening.

Measurement of uracil-DNA glycosylase activity by matrix assisted laser desorption/ionization time-of-flight mass spectrometry technique.

Uracil-DNA glycosylase (UDG) is a highly conserved DNA repair enzyme that acts as a key component in the base excision repair pathway to correct hydrolytic deamination of cytosine making it critical to genome integrity in living organisms. We report here a non-labeled, non-radio-isotopic and very specific method to measure UDG activity. Oligodeoxyribonucleotide duplex containing a site-specific G:U mismatch that is hydrolyzed by UDG then subjected to Matrix Assisted Laser Desorption/Ionization time-of-flight mass spectrometry analysis. A protocol was developed to maintain the AP product in DNA without strand break then the cleavage of uracil was identified by the mass change from uracil substrate to AP product. From UDG kinetic analysis, for G:U substrate the Km is 50 nM, Vmax is 0.98 nM/s and Kcat = 9.31 s-1. The method was applied to uracil glycosylase inhibitor measurement with an IC50 value of 7.6 pM. Single-stranded and double-stranded DNAs with uracil at various positions of the substrates were also tested for UDG activity albeit with different efficiencies. The simple, rapid, quantifiable, scalable and versatile method has potential to be the reference method for monofunctional glycosylase measurement, and can also be used as a tool for glycosylase inhibitors screening.

Proofreading of single nucleotide insertion/deletion replication errors analyzed by MALDI-TOF mass spectrometry assay.

Small nucleotide insertion/deletion (indel) errors are one of the common replication errors in DNA synthesis. The most frequent occurrence of indel error was thought to be due to repeated sequences being prone to slippage during DNA replication. Proofreading and DNA mismatch repair are important factors in indel error correction to maintain the high fidelity of genetic information transactions. We employed a MALDI-TOF mass spectrometry (MS) analysis to measure the efficiency of Klenow polymerase (KF) proofreading of indel errors. Herein, a non-labeled and non-radio-isotopic oligonucleotide primer is annealed to a template DNA forming a single nucleotide indel error and was proofread by KF in the presence of a combination of different deoxyribonucleotide triphosphates and/or dideoxyribonucleotide triphosphates. The proofreading products were identified by the KF modified mass change of the primer. We examined proofreading of DNAs containing indel errors at various positions of the primer-template junction. We found that indel errors located 1-5-nucleotides (nt) from the primer terminus can be proofread efficiently, while insertion/deletions at 6-nt from the 3' end are partially corrected and extended. Indels located 7-9-nt from the primer terminus escape proofreading and are elongated by polymerase. The possible underlying mechanisms of these observations are discussed in the context of the polymerase and primer-template junction interactions via a structure analysis.

Application of single nucleotide extension and MALDI-TOF mass spectrometry in proofreading and DNA repair assay.

Proofreading and DNA repair are important factors in maintaining the high fidelity of genetic information during DNA replication. Herein, we designed a non-labeled and non-radio-isotopic simple method to measure proofreading. An oligonucleotide primer is annealed to a template DNA forming a mismatched site and is proofread by Klenow fragment of Escherichia coli DNA polymerase I (pol I) in the presence of all four dideoxyribonucleotide triphosphates. The proofreading excision products and re-synthesis products of single nucleotide extension are subjected to MALDI-TOF mass spectrometry (MS). The proofreading at the mismatched site is identified by the mass change of the primer. We examined proofreading of Klenow fragment with DNAs containing various base mismatches. Single mismatches at the primer terminus can be proofread efficiently. Internal single mismatches can also be proofread at different efficiencies, with the best correction for mismatches located 2-4-nucleotides from the primer terminus. For mismatches located 5-nucleotides from the primer terminus there was partial correction and extension. No significant proofreading was observed for mismatches located 6-9-nucleotides from the primer terminus. We also subjected primers containing 3' penultimate deoxyinosine (dI) lesions, which mimic endonuclease V nicked repair intermediates, to pol I repair assay. The results showed that T-I was a better substrate than G-I and A-I, however C-I was refractory to repair. The high resolution of MS results clearly demonstrated that all the penultimate T-I, G-I and A-I substrates had been excised last 2 dI-containing nucleotides by pol I before adding a correct ddNMP, however, pol I proofreading exonuclease tolerated the penultimate C-I mismatch allowing the primer to be extended by polymerase activity.

Proofreading and DNA Repair Assay Using Single Nucleotide Extension and MALDI-TOF Mass Spectrometry Analysis.

The maintenance of the genome and its faithful replication is paramount for conserving genetic information. To assess high fidelity replication, we have developed a simple non-labeled and non-radio-isotopic method using a matrix-assisted laser desorption ionization with time-of-flight (MALDI-TOF) mass spectrometry (MS) analysis for a proofreading study. Here, a DNA polymerase [e.g., the Klenow fragment (KF) of Escherichia coli DNA polymerase I (pol I) in this study] in the presence of all four dideoxyribonucleotide triphosphates is used to process a mismatched primer-template duplex. The mismatched primer is then proofread/extended and subjected to MALDI-TOF MS. The products are distinguished by the mass change of the primer down to single nucleotide variations. Importantly, a proofreading can also be determined for internal single mismatches, albeit at different efficiencies. Mismatches located at 2-4-nucleotides (nt) from the 3' end were efficiently proofread by pol I, and a mismatch at 5 nt from the primer terminus showed only a partial correction. No proofreading occurred for internal mismatches located at 6 - 9 nt from the primer 3' end. This method can also be applied to DNA repair assays (e.g., assessing a base-lesion repair of substrates for the endo V repair pathway). Primers containing 3' penultimate deoxyinosine (dI) lesions could be corrected by pol I. Indeed, penultimate T-I, G-I, and A-I substrates had their last 2 dI-containing nucleotides excised by pol I before adding a correct ddN 5'-monophosphate (ddNMP) while penultimate C-I mismatches were tolerated by pol I, allowing the primer to be extended without repair, demonstrating the sensitivity and resolution of the MS assay to measure DNA repair.

DNA polymerase I proofreading exonuclease activity is required for endonuclease V repair pathway both in vitro and in vivo.

Deamination of adenine can occur spontaneously under physiological conditions to generate the highly mutagenic lesion, deoxyinosine (hypoxanthine deoxyribonucleotide, dI). In DNA, dI preferably pairs with cytosine rather than thymine and results in A:T to G:C transition mutations after DNA replication. The deamination of adenine is enhanced by ROS from exposure of DNA to ionizing radiation, UV light, nitrous acid, or heat. In Escherichia coli, dI repair is initiated by endonuclease V (endo V; nfi gene product) nicking but a complete repair mechanism has yet to be elucidated. Using in vitro minimum component reconstitution assays, we previously showed that endo V, DNA polymerase I (pol I), and E. coli DNA ligase were sufficient to repair this dI lesions efficiently and that the 3'-5' exonuclease of pol I is essential. Here we employed a phagemid-based T-I substrate mimicking adenine deamination product to demonstrate pol I proofreading exonuclease is required by the endo V repair pathway both in vitro and in vivo. In vivo we found that the repair level of an nfi mutant (11%) was almost 8-fold lower than the wild type (87%). while the polA-D424A strain, a pol I mutant defective in 3'-5' exonuclease, showed a high repair level similar to wild type (both more than 80%). Using additional C-C mismatch as strand discrimination marker we found that the high level of dI removal in polA-D424A was due to strand loss (more than 60%) associated with incomplete repair. Thus, pol I proofreading exonuclease is the major function responsible for dI lesion removal after endoV nicking both in vitro and in vivo. Finally, using MALDI-TOF to analyze single-nucleotide extension product we show that the pol I proofreading exonuclease excises only 2-nt 5' upstream of endo V incision site further honing the role of pol I in the endoV dI dependent repair pathway.

Relation of improvement in endothelium-dependent flow-mediated vasodilation after rosiglitazone to changes in asymmetric dimethylarginine, endothelin-1, and C-reactive protein in nondiabetic patients with the metabolic syndrome.

The mechanisms by which thiazolidinediones exert beneficial effects on the endothelium are still not clear. We examined the effects of rosiglitazone on the plasma markers of metabolic control (glucose, insulin, adiponectin, resistin, and lipid profiles), markers of inflammation (high-sensitivity C-reactive protein [CRP], interleukin-6, soluble CD40 ligand, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1), and markers of vasoreactivity (asymmetric dimethylarginine [ADMA] and endothelin-1) and analyzed the relations between changes in endothelium-dependent flow-mediated dilation of the brachial artery and changes in these markers to elucidate their roles in mediating the vascular protective effects of rosiglitazone. Of 70 nondiabetic patients who met a modified National Cholesterol Education Program definition of the metabolic syndrome, 35 were randomized to receive rosiglitazone (4 mg/day) and 35 to receive placebo for 8 weeks. At study end, treatment with rosiglitazone had significantly reduced plasma insulin (-25%, p = 0.004) and resistin (-16%, p <0.001), increased adiponectin (164%, p <0.001), low-density lipoprotein cholesterol (16%, p = 0.005), and apolipoprotein-B (14%, p = 0.003), and decreased CRP (-30%, p = 0.005), soluble CD40 ligand (-20%, p = 0.014), ADMA (-16%, p <0.001), and endothelin-1 (-11%, p <0.001) concentrations and systolic and diastolic blood pressures. Rosiglitazone treatment significantly improved flow-mediated dilation (p <0.001) and nitroglycerin-induced vasodilation (p = 0.001) of the right brachial artery. On multivariate analysis, changes in ADMA, endothelin-1, and CRP were independent predictors of improved endothelial reactivity with rosiglitazone. In conclusion, we have, for the first time, demonstrated the independent associations between the improvement in flow-mediated dilation and reductions in ADMA, endothelin-1, and CRP after 8 weeks of treatment with rosiglitazone in nondiabetic patients with the metabolic syndrome. These findings suggest that decreases in ADMA, endothelin-1, and CRP may serve as possible mechanisms for the improvement in endothelial function conferred by rosiglitazone treatment.

Increased high sensitivity C-reactive protein and neutrophil count are related to increased standard cardiovascular risk factors in healthy Chinese men.

BACKGROUND: Epidemiologic data regarding the role of inflammation in atherosclerosis have been based mainly on Caucasian populations. Thus, we analyzed the cross-sectional relationships of inflammatory biomarkers to cardiovascular risk factors (CVRF) and related variables in a large group of healthy Chinese men, a population with a markedly lower heart disease mortality rate compared with Western populations. METHODS: The study consisted of 8374 men aged 20-80 who attended a voluntary health examination at a metropolitan university center between 1997 and 2002. The relationships between serum high sensitivity C-reactive protein (hsCRP), total white blood cell (WBC), neutrophil, and monocyte counts to CVRF were analyzed using multivariate linear and logistic regression analyses. Whether a dose-response effect existed between elevated levels of each marker and increasing numbers of CVRF was also evaluated. RESULTS: The distribution of hsCRP was similar to Western studies. Both multivariate regression analyses showed all four markers to have significant correlations with body mass index, triglycerides, and adverse high density lipoprotein/low density lipoprotein ratio. Smoking was associated with increased levels of all four markers. Elevated neutrophil count had the most markedly progressive dose-response effect with increasing numbers of CVRF, whereas elevated monocyte count showed a drop in risk with CVRF of five and above. CONCLUSION: We show in our study that with increasing numbers of standard CVRF, healthy Chinese men have progressive and increasing risks of having elevated levels of hsCRP, total WBC, and neutrophil counts. While the inflammatory markers surveyed were largely correlated with CVRF, the similar values of CRP between populations with divergent mortality rates suggest that a more complex relationship may exist between CRP and disease outcome. The possible utility of neutrophil count as a marker for cardiovascular disease risk in healthy men awaits further evaluation in prospective studies.

Deoxyinosine repair in nuclear extracts of human cells.

BACKGROUND: Deamination of adenine can occur spontaneously under physiological conditions generating the highly mutagenic lesion, hypoxanthine. This process is enhanced by ROS from exposure of DNA to ionizing radiation, UV light, nitrous acid, or heat. Hypoxanthine in DNA can pair with cytosine which results in A:T to G:C transition mutations after DNA replication. In Escherichia coli, deoxyinosine (hypoxanthine deoxyribonucleotide, dI) is removed through an alternative excision repair pathway initiated by endonuclease V. However, the correction of dI in mammalian cells appears more complex and was not fully understood. RESULTS: All four possible dI-containing heteroduplex DNAs, including A-I, C-I, G-I, and T-I were introduced to repair reactions containing extracts from human cells. The repair reaction requires magnesium, dNTPs, and ATP as cofactors. We found G-I was the best substrate followed by T-I, A-I and C-I, respectively. Moreover, judging from the repair requirements and sensitivity to specific polymerase inhibitors, there were overlapping repair activities in processing of dI in DNA. Indeed, a hereditable non-polyposis colorectal cancer cell line (HCT116) demonstrated lower dI repair activity that was partially attributed to lack of mismatch repair. CONCLUSIONS: A plasmid-based convenient and non-radioisotopic method was created to study dI repair in human cells. Mutagenic dI lesions processed in vitro can be scored by restriction enzyme cleavage to evaluate the repair. The repair assay described in this study provides a good platform for further investigation of human repair pathways involved in dI processing and their biological significance in mutation prevention.

Laboratory and clinical characterization of monoclonal gammopathy in Taiwanese.

BACKGROUND AND PURPOSE: To investigate the prevalence of monoclonal gammopathy, the frequency of associated diseases, and the laboratory features useful in the differential diagnosis and prediction of associated complications. MATERIALS AND METHODS: From January 1994 through December 1998, 11,510 serum samples and 1,555 urine samples from 10,974 Taiwanese patients requiring electrophoresis study were examined for the presence of monoclonal protein by electrophoresis on cellulose acetate membrane and immunofixation electrophoresis (IFE). RESULTS: Two hundred and eighty seven cases (2.6%) of monoclonal gammopathy were found. Of these, 136 (47.4%) had multiple myeloma, 84 (29.3%) had monoclonal gammopathy of undetermined significance (MGUS), 53 (18.5%) had other lymphoproliferative disorders (LPD), eight (2.8%) had polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, skin pigmentation (POEMS) syndrome, and six (2.1%) had cryoglobulinemia. Immunoglobulin A (IgA) monoclonal protein was more often associated with myeloma than LPD (25 vs 3.8%, p = 0.002); monoclonal light chains were more often associated with myeloma than MGUS (17% vs 3.6%, p = 0.006). Biclonal gammopathy was more often associated with MGUS than myeloma (10.7 vs 1.5%, p = 0.014). Hypogammaglobulinemia was common in patients with myeloma (70%) but rare in patients with LPD (20%, p < 0.001) and in those with MGUS (5%, p < 0.001). Concomitant polyclonal hypergammaglobulinemia was rare in patients with myeloma (5%), but common in patients with LPD (53%, p < 0.001) or MGUS (27%, p < 0.001). Patients with lambda chain myeloma had the highest risk (100%) of developing renal insufficiency. Our myeloma patients were also at increased risk of developing myelomatous pleural effusions than previously reported. CONCLUSIONS: The lower frequency of MGUS in this study than previously reported may have been due to differences in patient selection, laboratory methods, and the presence of local diseases. The presence of POEMS syndrome and cryoglobulinemia, the very high association of lambda chain myeloma with renal failure, and the higher occurrence of myelomatous effusion than previously reported probably reflected local disease patterns.

The excision of 3' penultimate errors by DNA polymerase I and its role in endonuclease V-mediated DNA repair.

Deamination of adenine can occur spontaneously under physiological conditions, and is enhanced by exposure of DNA to ionizing radiation, UV light, nitrous acid, or heat, generating the highly mutagenic lesion of deoxyinosine in DNA. Such DNA lesions tends to generate A:T to G:C transition mutations if unrepaired. In Escherichia coli, deoxyinosine is primarily removed through a repair pathway initiated by endonuclease V (endo V). In this study, we compared the repair of three mutagenic deoxyinosine lesions of A-I, G-I, and T-I using E. coli cell-free extracts as well as reconstituted protein system. We found that 3'-5' exonuclease activity of DNA polymerase I (pol I) was very important for processing all deoxyinosine lesions. To understand the nature of pol I in removing damaged nucleotides, we systemically analyzed its proofreading to 12 possible mismatches 3'-penultimate of a nick, a configuration that represents a repair intermediate generated by endo V. The results showed all mismatches as well as deoxyinosine at the 3' penultimate site were corrected with similar efficiency. This study strongly supports for the idea that the 3'-5' exonuclease activity of E. coli pol I is the primary exonuclease activity for removing 3'-penultimate deoxyinosines derived from endo V nicking reaction.

Patterns, effects, and thoracic volume changes of thoracoscopic pleurodesis in rabbits.

BACKGROUND: The ideal thoracoscopic pleurodesis method for preventing recurrence of spontaneous pneumothorax remains controversial. This study was conducted to compare the patterns, effects, and thoracic volume changes achieved using a variety of thoracoscopic procedures in rabbits. MATERIALS AND METHODS: Thirty-six New Zealand White rabbits were randomly assigned to undergo the following thoracoscopic procedures in the left hemithorax: (a) parietal pleural abrasion; (b) minocycline instillation; (c) combination of abrasion and minocycline; or (d) examination alone. The rabbits were euthanatized 30 days after the operation to determine pleurodesis score, area of greatest adhesion, thoracic volume change, and histopathological findings. RESULTS: Grossly, pleural abrasion produced moderate localized apical pleural symphysis with no obvious thoracic volume change. Minocycline instillation induced moderate generalized pleurodesis with a significant decrease in thoracic volume. The combination of abrasion and minocycline instillation produced the greatest generalized pleurodesis as well as a significant decrease in thoracic volume. On microscopic examination, the combination procedure produced the greatest inflammation and fibrosis of the visceral and parietal pleura. Increased intensity of pleurodesis score as well as pleural inflammation and fibrosis is associated with decreased thoracic volume. CONCLUSIONS: Thoracoscopic pleurodesis achieved using pleural abrasion and minocycline instillation induced different patterns of pleurodesis, and a combination of each method generated a synergy and produced a better pleurodesis. However, as the generalization and intensity of the pleurodesis were inversely associated with thoracic volume, the optimal method should be determined on an individual basis according to the clinical situation.