Dissemination of an international high-risk clone of Escherichia coli ST410 co-producing NDM-5 and OXA-181 carbapenemases in Seoul, Republic of Korea

The rapid increase in carbapenemase-producing Enterobacterales is a global health concern. During 2017-2020, a total of 44 Escherichia coli isolates co-harbouring bla_NDM-5 and bla_OXA-181 were collected from patients at 17 hospitals in Seoul and characterized based on antimicrobial susceptibility, resistance genes and plasmid replicons detected using polymerase chain reaction (PCR). Clonal relatedness was estimated using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). All isolates had an identical multidrug resistance profile, including resistance to carbapenems, cephalosporins, ciprofloxacin, tetracycline, and trimethoprim/sulfamethoxazole, and susceptibility to amikacin, colistin, and tigecycline. Resistance genes (bla_CTX-M-15, bla_CMY-2, bla_TEM-1B, bla_OXA-1, aac(6')-Ib-cr, and qnrS) and plasmid replicons (IncFIA, IncFIB, and IncX3) was observed in almost all isolates. All isolates belonged to ST410 and were genetically similar (>88% similarity), with some PFGE types shared among isolates from different hospitals. Analysis of the whole genome revealed that the isolates clustered together with other strains of the international high-risk clone ST410 B4/H24RxC from other countries. These findings underline the ongoing spread of the high-risk clone of NDM-5- and OXA-181-producing E. coli ST410 B4/H24RxC among hospitals in Seoul. Continuous monitoring and implementation of infection control measures are crucial to track and prevent further spread of these resistant strains.

Distribution of mcr genes among carbapenem-resistant Enterobacterales clinical isolates: High prevalence of mcr-positive Enterobacter cloacae complex in Seoul, Republic of Korea

Colistin is usually used as a drug of last resort against infections caused by multidrug-resistant gram-negative bacteria, including carbapenem-resistant Enterobacterales (CRE). Recently, the acquisition of mobile colistin resistance (mcr) genes by CRE is a cause for worry. Here, we investigated the prevalence of mcr genes in CRE isolates in Seoul, Korea. A total of 3,675 CRE strains were collected from patients between 2018 and 2019 and initially screened for mcr genes using multiplex-PCR assays. Upon the identification of mcr-harboring strains, colistin susceptibility tests, identification of carbapenemase and β-lactamase genes, and plasmid replicon typing were performed. Clonal analysis was conducted using pulsed-field gel electrophoresis. mcr genes were detected in 2.2% (80/3,675) CRE strains. There were three mcr-1, one mcr-4.3, one mcr-4.3/mcr-9, 58 mcr-9, one mcr-9/mcr-10, and 16 mcr-10 carriers from various Enterobacterales species, of which 60 were in Enterobacter cloacae complex (ECC) strains. The mcr prevalence in ECC was 20.5%. Molecular detection confirmed that 21.3% and 13.8% of the mcr-harboring strains shared bla_NDM-1 or bla_KPC-2, respectively. In addition, an IncHI2 replicon was identified in 71.7% of the mcr-9 strains. Comparative analysis revealed not only a notable diversity of mcr carriers, but also clonal spreading or nosocomial outbreak of some ECC strains. Our findings revealed a silent distribution of mcr in CRE strains with high genetic heterogeneity in Seoul, underscoring the urgent need for timely intervention to control and prevent mcr dissemination.

Yield Stress Enhancement of a Ternary Colloidal Suspension via the Addition of Minute Amounts of Sodium Alginate to the Interparticle Capillary Bridges

Capillary suspensions are ternary solid-liquid-liquid systems produced via the addition of a small amount of secondary fluid to the bulk fluid that contained the dispersed solid particles. The secondary fluid could exert strong capillary forces between the particles and dramatically change the rheological properties of the suspension. So far, research has focused on capillary suspensions that consist of additive-free fluids, whereas capillary suspensions with additives, particularly those of large molecular weight that are highly relevant for industrial purposes, have been relatively less studied. In this study, we performed a systematic analysis of the properties of capillary suspensions that consist of paraffin oil (bulk phase), water (secondary phase), and α-Al₂O₃ microparticles (particle phase), in which the aqueous secondary phase contained an important eco-friendly polymeric binder, sodium alginate (SA). It was determined that the yield stress of the suspension increased significantly with the increase in the SA content in the aqueous secondary phase, which was attributed to the synergistic effect of the capillary force and hydrogen bonding force that may be related to the increase in the number of capillary bridges. The amounts of SA used to induce a significant change in the yield stress in this study were very small (<0.02% of the total sample volume). The addition of Ca²⁺ ions to the SA-containing secondary phase further increased the yield stress with possible gelation of the SA chains-in the presence of excess Ca²⁺ ions, however, the yield stress decreased because of the microscopic phase separation that occurred in the aqueous secondary phase. The microstructures of the sintered porous materials that were produced by using capillary suspensions as precursors were qualitatively well correlated to the rheological behavior of the precursor suspensions, suggesting a new method for the subtle control of the microstructures of porous materials using the addition of minute amounts of polymeric additives.

Arsenic induces platelet shape change through altering focal adhesion kinase-mediated actin dynamics, contributing to increased platelet reactivity

Arsenic, an environmental contaminant in drinking water worldwide is well-established to increase cardiovascular diseases (CVDs) in humans. Of these, thrombotic events represent a major adverse effect associated with arsenic exposure, for which an abundance of epidemiological evidence exists. Platelet aggregation constitutes a pivotal step in thrombosis but arsenic alone doesn't induce aggregation and the mechanism underlying arsenic-induced thrombosis still remains unclear. Here we demonstrated that arsenic induces morphological changes of platelets, i.e., contraction and pseudopod projection, the primal events of platelet activation, which can increase platelet reactivity. Arsenite induced prominent platelet shape changes in a dose-dependent manner in freshly isolated human platelets. Of note, arsenite suppressed focal adhesion kinase (FAK) activity, which in turn activated RhoA, leading to altered actin assembly through LIMK activation, and subsequent cofilin inactivation. Arsenic-induced platelet shape change appeared to increase the sensitivity to thrombin and ADP-induced aggregation. Supporting this, latrunculin A, an inhibitor of actin-dynamics abolished it. Taken together, we demonstrated that arsenic induces cytoskeletal changes and shape changes of platelets through FAK-mediated alteration of actin dynamics, which renders platelets reactive to activating stimuli, ultimately contributing to increased thrombosis.

Mid-term outcomes of routine proximal row carpectomy compared with proximal row carpectomy with dorsal capsular interposition arthroplasty for the treatment of late-stage arthropathy of the wrist

AIMS

The aims of this study were to compare the mid-term outcomes of patients with late-stage arthritis of the wrist treated with proximal row carpectomy (PRC) and dorsal capsular interposition (DCI) arthroplasty with a matched cohort treated with routine PRC alone.

PATIENTS AND METHODS

A total of 25 arthritic wrists (24 patients) with pre-existing degenerative changes of the proximal capitate and/or the lunate fossa of the radius were treated with PRC + DCI over a ten-year period. This group of patients were matched 1:2 with a group of 50 wrists (48 patients) without degenerative changes in the capitate or lunate fossa that were treated with a routine PRC alone during the same period. The mean age of the patients at the time of surgery was 56.8 years (25 to 81), and the demographics and baseline range of movement of the wrist, grip strength, Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) score, and Patient-Rated Wrist Evaluation (PRWE) score were similar in both groups.

RESULTS

At a mean follow-up of 5.9 years (1.8 to 11.8), significant improvements in mean grip strength, the flexion-extension arc of movement of the wrist, QuickDASH, and PRWE scores were seen in both groups. There was no diifference between the groups for any of the outcomes. One patient in the PRC + DCI group required additional surgery for a deep infection, while two in the PRC group had complications (one wound dehiscence requiring revision closure, one transient radial sensory neuritis). One patient in each group required total arthrodesis of the wrist for progressive degenerative radiocarpal changes. A total of 70 patients (93%) were satisfied with the outcomes.

CONCLUSION

PRC with DCI is an effective form of treatment for late-stage arthritis of the wrist involving the capitolunate joint, with mid-term outcomes that are similar to those in patients without degenerative changes affecting the capitate or lunate fossa who are treated with a routine PRC alone. Cite this article: Bone Joint J 2018;100-B:197-204.

Incremental Treatment Costs Attributable to Overweight and Obesity in Patients with Diabetes: Quantile Regression Approach

OBJECTIVE

This study aimed to estimate treatment costs attributable to overweight and obesity in patients with diabetes who were less than 65 years of age in the United States.

METHODS

This study used data from the Medical Expenditure Panel Survey from 2001 to 2013. Patients with diabetes were identified by using the International Classification of Diseases, Ninth Revision, Clinical Modification code (250), clinical classification codes (049 and 050), or self-reported physician diagnoses. Total treatment costs attributable to overweight and obesity were calculated as the differences in the adjusted costs compared with individuals with diabetes and normal weight. Adjusted costs were estimated by using generalized linear models or unconditional quantile regression models.

RESULTS

The mean annual treatment costs attributable to obesity were $1,852 higher than those attributable to normal weight, while costs attributable to overweight were $133 higher. The unconditional quantile regression results indicated that the impact of obesity on total treatment costs gradually became more significant as treatment costs approached the upper quantile.

CONCLUSIONS

Among patients with diabetes who were less than 65 years of age, patients with diabetes and obesity have significantly higher treatment costs than patients with diabetes and normal weight. The economic burden of diabetes to society will continue to increase unless more proactive preventive measures are taken to effectively treat patients with overweight or obesity.

Platelet Shape Changes and Cytoskeleton Dynamics as Novel Therapeutic Targets for Anti-Thrombotic Drugs

Platelets play an essential role in hemostasis through aggregation and adhesion to vascular injury sites but their unnecessary activation can often lead to thrombotic diseases. Upon exposure to physical or biochemical stimuli, remarkable platelet shape changes precede aggregation or adhesion. Platelets shape changes facilitate the formation and adhesion of platelet aggregates, but are readily reversible in contrast to the irrevocable characteristics of aggregation and adhesion. In this dynamic phenomenon, complex molecular signaling pathways and a host of diverse cytoskeleton proteins are involved. Platelet shape change is easily primed by diverse pro-thrombotic xenobiotics and stimuli, and its inhibition can modulate thrombosis, which can ultimately contribute to the development or prevention of thrombotic diseases. In this review, we discussed the current knowledge on the mechanisms of platelet shape change and also pathological implications and therapeutic opportunities for regulating the related cytoskeleton dynamics.

Comparison of Total Arch and Partial Arch Transposition During Hybrid Endovascular Repair for Aortic Arch Disease

OBJECTIVE

Total arch transposition (TAT) during hybrid endovascular repair for aortic arch disease is believed to allow a better landing zone, but also to be associated with higher peri-operative mortality than partial arch transposition (PAT). Information on this issue is limited.

METHOD

This study was a retrospective analysis. All 53 consecutive patients with aortic arch disease (41 males, mean age 65.0 years) who underwent hybrid endovascular repair with TAT (zone 0, n=20) or PAT (zone 1 or 2, n=33) from 2008 to 2014 were analyzed retrospectively. The peri-operative and late outcomes of these two groups were compared.

RESULTS

Baseline characteristics, including EuroSCORE II results, were similar in the two groups. After procedures, peri-operative mortalities and stroke rates were similar in the two groups (5.0% vs. 9.1%, p=1.000, and 10.0% vs. 6.1%, p=.627). Interestingly, all four strokes occurred in patients with a type III aortic arch irrespective of transposition type. Primary success rates (80.0% vs. 69.7%, p=.527) and type I endoleak incidences (20.0% vs. 27.3%, p=.744) were not significantly different. During follow up (mean duration 36.9 months), overall survival (89.7% vs. 87.4% at 1 year and 89.7% vs. 79.3% at 3 years; p=.375) and re-intervention free survival rates (78.6% vs. 92.0% at 1 year; 72.0% vs. 62.2% at 3 years, p=.872) were similar in the two groups.

CONCLUSION

Morbidity and mortality were high within the first year of hybrid endovascular therapy for aortic arch disease, implying that candidates for hybrid procedures need to be selected carefully. Hybrid endovascular repair with TAT was found to have peri-operative mortality, stroke, and long-term survival rates comparable with PAT, so hybrid endovascular repair may be considered, irrespective of type of arch reconstruction, when clinically indicated.

Relationships among ketosis, serum metabolites, body condition, and reproductive outcomes in dairy cows

We determined the relationships among ketosis, serum metabolites, body condition, and reproductive disorders and performance in dairy cows. Blood samples from 213 dairy cows were collected at 4 and 2 weeks prepartum, just after calving, and at 1, 2, 4, 6, and 8 weeks postpartum to measure serum β-hydroxybutyrate, nonesterified fatty acids (NEFAs), glucose, total cholesterol, urea nitrogen, aspartate aminotransferase, γ-glutamyltransferase, and progesterone concentrations. Cows were grouped on the basis of the β-hydroxybutyrate concentration at 1 and/or 2 weeks postpartum into two groups: the ketotic group (≥1200 μmol/L, n = 59) and the nonketotic group (<1200 μmol/L, n = 154). The body condition score (BCS) was assessed simultaneously with blood collection. Clinical endometritis was diagnosed by observation of vaginal discharges (>50% pus), and subclinical endometritis was diagnosed by evaluation of uterine cytology (>18% neutrophils) at 4 weeks postpartum. Ovarian cysts were diagnosed by ultrasonography, and resumption of postpartum cyclicity was evaluated by progesterone concentrations (≥1 ng/mL) at 4, 6, and 8 weeks postpartum. In the ketotic group, NEFA levels were higher (P ≤ 0.0005), whereas glucose (P < 0.05-0.0005) and urea nitrogen levels (P < 0.05-0.01) were lower than those in the nonketotic group during the postpartum period. Aspartate aminotransferase levels were higher (P < 0.01) in the ketotic group than those in the nonketotic group at 2 weeks postpartum. The BCS of the ketotic group was higher than the nonketotic group during the prepartum (P < 0.001) and postpartum (P < 0.05-0.001) periods. The probabilities of clinical endometritis (odds ratio = 2.55) and ovarian cysts (odds ratio = 2.80) were higher (P < 0.05) in the ketotic group than those in the nonketotic group. The hazards of resumption of postpartum cyclicity by 8 weeks postpartum (hazard ratio = 0.67) and pregnancy by 360 days postpartum (hazard ratio = 0.68) were lower (P < 0.05) in the ketotic group. In conclusion, a higher BCS during prepartum and postpartum period and increased NEFA and aspartate aminotransferase levels, along with decreased glucose and urea nitrogen levels during postpartum, were associated with ketosis, increased reproductive disorders, and decreased reproductive performance in dairy cows.

Comparison of sodium content of workplace and homemade meals through chemical analysis and salinity measurements

BACKGROUND/OBJECTIVES

Most Koreans consume nearly 70-80% of the total sodium through their dishes. The use of a salinometer to measure salinity is recommended to help individuals control their sodium intake. The purpose of this study was to compare sodium content through chemical analysis and salinity measurement in foods served by industry foodservice operations and homemade meals.

MATERIALS/METHODS

Workplace and homemade meals consumed by employees in 15 cafeterias located in 8 districts in Daegu were collected and the sodium content was measured through chemical analysis and salinity measurements and then compared. The foods were categorized into 9 types of menus with 103 workplace meals and 337 homemade meals.

RESULTS

Workplace meals did not differ significantly in terms of sodium content per 100 g of food but had higher sodium content via chemical analysis in roasted foods per portion. Homemade meals had higher broth salt content and higher salt content by chemical analysis per 100 g of roasted foods and hard-boiled foods. One-dish workplace meals had higher salinity (P < 0.05), while homemade broths and stews had higher sodium content (P < 0.05 and P < 0.01, respectively). The sodium content per 100 g of foods was higher in one-dish workplace meals (P < 0.05) and in homemade broths and stews (P < 0.01 and P < 0.05, respectively).

CONCLUSIONS

The use of a salinometer may be recommended to estimate the sodium content in foods and control one's sodium intake within the daily intake target as a way to promote cooking bland foods at home. However, estimated and actual measured values may differ.

Comparison of four diagnostic methods for detecting rabies viruses circulating in Korea

It is essential to rapidly and precisely diagnose rabies. In this study, we evaluated four diagnostic methods, indirect fluorescent antibody test (FAT), virus isolation (VI), reverse transcriptase polymerase chain reaction (RT-PCR), and rapid immunodiagnostic assay (RIDA), to detect rabies in animal brain homogenates. Out of the 110 animal brain samples tested, 20 (18.2%) were positive for rabies according to the FAT. Compared to the FAT, the sensitivities of VI, RT-PCR, and RIDA were 100, 100, and 95%, respectively. The specificities of VI, RT-PCR and RIDA were found to be 100, 100, and 98.9%, respectively. Rabies viruses circulating in Korea were isolated and propagated in murine neuroblastoma (NG108-15) cells with titers ranging from 10^1.5 to 10^4.5 TCID₅₀/mL. Although the RIDA findings did not completely coincide with results obtained from FAT, VI, and RT-PCR, RIDA appears to be a fast and reliable assay that can be used to analyze brain samples. In summary, the results from our study showed that VI, RT-PCR, and RIDA can be used as supplementary diagnostic tools for detecting rabies viruses in both laboratory and field settings.

Indirubin derivative E804 inhibits angiogenesis

Background

It has previously been shown that indirubin derivative E804 (IDR-E804) blocks signal transducer and activator of transcription-3 signaling in human breast and prostate cancer cells and inhibits Src kinase activity. To further establish its role in angiogenesis, we tested its potential using human umbilical vein endothelial cells (HUVECs) and analyzed the effects of IDR-E804 on cellular and molecular events related to angiogenesis.

Methods

The anti-angiogenic effects of IDR-E804 were examined by assessing the proliferation, migration and capillary tube formation of HUVECs were induced by vascular endothelial growth factor (VEGF) with or without various concentrations of IDR-E804. The inhibitory effect of IDR-E804 angiogenesis and tumor growth in vivo was also investigated in Balb/c mice subcutaneously transplanted with CT-26 colon cancer cells.

Results

IDR-E804 significantly decreased proliferation, migration and tube formation of vascular endothelial growth factor VEGF-treated HUVECs. These effects were accompanied by decreased phosphorylation of VEGF receptor (VEGFR)-2, AKT and extracellular signal regulated kinase in VEGF-treated HUVECs. Intratumor injections of IDR-E804 inhibited the growth of subcutaneously inoculated CT-26 allografts in syngenic mice. Immunohistochemistry revealed a decreased CD31 microvessel density index and Ki-67 proliferative index, but an increased apoptosis index in IDR-E804-treated tumors.

Conclusions

These data revealed that IDR-E804 is an inhibitor of angiogenesis and also provide evidence for the efficacy of IDR-E804 for anti-tumor therapies.

Suppression of inflammatory responses by celastrol, a quinone methide triterpenoid isolated from Celastrus regelii

BACKGROUND

Celastrol, a quinone methide triterpenoid isolated from the Celastraceae family, exhibits various biological properties, including chemopreventive, antioxidant and neuroprotective effects. In this study, we showed that celastrol inhibits inflammatory reactions in macrophages and protects mice from skin inflammation.

MATERIALS AND METHODS

Anti-inflammatory effects of celastrol (0-1 microM) were examined in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. To investigate the effects of celastrol (0-50 microg per mice) in vivo, activation of myeloperoxidase (MPO) and histological assessment were examined in the 12-O-tetradecanoyl-phorbol-13-acetate (TPA)-induced mouse ear oedema model.

RESULTS

Our in vitro experiments showed that celastrol suppressed not only LPS-stimulated generation of nitric oxide and prostaglandin E(2), but also expression of inducible nitric oxide synthase and cyclooxygenase-2 in RAW264.7 cells. Similarly, celastrol inhibited LPS-induced production of inflammatory cytokines, including tumour necrosis factor-alpha and interleukin-6. In an animal model, celastrol protected mice from TPA-induced ear oedema, possibly by inhibiting MPO activity and production of inflammatory cytokines.

CONCLUSIONS

Our data suggest that celastrol inhibits the production of inflammatory mediators and is a potential target for the treatment of various inflammatory diseases.

Comparison of inflammatory markers and angiographic outcomes after implantation of sirolimus and paclitaxel-eluting stents

OBJECTIVE

We compared the degree of systemic inflammation and its relation to the angiographic outcomes after drug-eluting stent (DES) implantations.

METHODS

We implanted a single DES in 79 stable angina patients (50 men; 60.4 (9.5) years of age; sirolimus-eluting stent (SES), n = 38; paclitaxel-eluting stent (PES), n = 41). The high-sensitivity C-reactive protein (hs-CRP) and interleukin 6 (IL-6) levels were determined before and at 24 hours, 72 hours, and 4 weeks after the percutaneous coronary intervention (PCI). An angiography and intravascular ultrasound (IVUS) were performed.

RESULTS

The hs-CRP and IL-6 levels at baseline did not differ between the two groups. The hs-CRP increased significantly from baseline at 24 hours and 72 hours after the PCI in both groups and there was a significant increase in the IL-6 level at 24 hours after the PCI in both groups. However, there was no significant difference between the two groups in any of the hs-CRP or IL-6 measurements. At follow-up, the late lumen loss was significantly higher in the PES group than in the SES group (0.57 (0.56) mm vs 0.28 (0.58) mm, respectively, p = 0.020). The neointimal hyperplasia (NIH) volume in the PES group was significantly higher than that in the SES group (23.1 (22.7) vs 3.8 (7.1) mm(3), respectively, p = 0.000). The percentage luminal volume reduction was higher in the PES group than in the SES group (18.9 vs 3.9%, p = 0.002). The absolute values or change in the inflammatory markers did not correlate with the NIH or stent volume reduction.

CONCLUSIONS

Our study showed that the benefits obtained from the SES, which reduce neointimal proliferation, are not probably mediated by the attenuation of the systemic inflammatory markers hs-CRP or IL-6.

Polymorphism of pertactin gene repeat regions in Bordetella bronchiseptica isolates from pigs

Bordetella bronchiseptica pertactin (prn) is an outer membrane protein which has been implicated as both an adhesin and a protective antigen that induces immunity against atrophic rhinitis in pigs. Previous studies demonstrated extensive heterogeneity of the prn sequence within two distinct regions of amino acid repeats for B. bronchiseptica isolated from the United States and Europe. By deducing the amino acid sequences of the repeat regions of the prn gene from recent isolates from Korea, two region 1 variants and five region 2 variants were identified. Five pertactin types were distinguished based on combinations of variants of both regions. Interestingly, none of the field isolates have the same pertactin type as the B. bronchiseptica P4 strain widely used to vaccinate pigs.

Optimal conditions for cryopreservation of primary chicken embryo kidney cells with dimethyl sulfoxide

Conditions were evaluated for optimum cryopreservation of primary chicken embryo kidney (CEK) cells. The recovery of viable CEK cells was best (50.8% viability) when the concentration of dimethyl sulfoxide (DMSO) in the freezing medium was 20% (v/v). The viability of primary CEK cells was not influenced by the concentration of calf serum in the freezing medium, the duration of storage at -70 degrees C before storage in liquid nitrogen, cell concentration, or the method of addition or dilution of DMSO. Thawed cells recovered and grew in complete growth medium similarly to cells freshly isolated from kidney, and influenza viruses produced plaques in the monolayer. The cryopreservation procedures described here may facilitate maintenance of a standard stock of primary CEK cells for laboratories where preparation of primary CEK cells is not an option.

Current concepts in the management of distal radius fractures

The treatment of fractures at the distal end of the radius continues to challenge orthopaedic and upper extremity surgeons. As our understanding of the injury mechanism and local anatomy continues to improve, so too have our surgical techniques in helping patients regain functional use of the injured extremity. The purpose of this manuscript is to review the treatment methods available for distal radius fracture management.

Pulsed-field gel electrophoresis genotyping of Salmonella gallinarum and comparison with random amplified polymorphic DNA

Salmonella gallinarum is gram-negative bacteria that cause fowl typhoid (FT) in chickens. Since the first outbreak of FT reported in 1992 in Korea, it has widely spread throughout the country. Today, FT is one of the most devastating diseases of poultry. The aim of the present study was to ascertain a genetic relationship among S. gallinarum isolates collected from different regions of Korea over a 10-year period. We examined a total of 38 isolates of S. gallinarum obtained in 29 regions of Korea from 1992 to 2001 including the 9R vaccine strain and the standard strain of S. gallinarum (ATCC 9184). The PFGE profiles produced 12 different patterns with the XbaI-digestion and 11 different patterns with the SpeI-digestion. The RAPD using URP-6 primers showed eight different genotypes with the same Salmonella isolates. The PFGE patterns of the 9R vaccine strain and ATCC 9184 of S. gallinarum were different from the identical type A, the most common genotype among field isolates in our study. In conclusion, a low genetic heterogeneity was observed among Korean S. gallinarum isolates. In addition, PFGE appeared to be a more accurate and reproducible method for genotyping of S. gallinarum isolates than RAPD.

Treatment of multiple hereditary osteochondromas of the forearm in children

We have evaluated the clinical outcomes of simple excision, ulnar lengthening and the Sauvé-Kapandji procedure in the treatment of deformities of the forearm in patients with multiple hereditary osteochondromas. The medical records of 29 patients (33 forearms) were reviewed; 22 patients (22 forearms) underwent simple excision (four with ulnar lengthening) and seven the Sauvé-Kapandji procedure.

Simple excision increased the mean supination of the forearm from 63.2° to 75.0° (p = 0.049). Ulnar lengthening did not significantly affect the clinical outcome. The Sauvé-Kapandji technique improved the mean pronation from 33.6° to 55.0° (p = 0.047) and supination from 70.0° to 81.4° (p = 0.045). Simple excision may improve the range of movement of the forearm but will not halt the progression of disease, particularly in younger patients. No discernable clinical or radiological improvement was noted with ulnar lengthening. The Sauvé-Kapandji procedure combined with simple excision of osteochondromas can improve stability of the wrist, movement of the forearm and the radiological appearance.

Molecular Typing by Random Amplification of Polymorphic DNA (RAPD) and Detection of Virulence Genes of Salmonella enterica subspecies enterica serovar Gallinarum biovar Gallinarum

Salmonella enterica subspecies enterica serovar Gallinarum biovar Gallinarum is the causative agent of fowl typhoid in chickens, outbreaks of which have devastated poultry populations in Korea since 1992. In order to identify genetic differences among S. Gallinarum isolates, bacteria were examined using the random amplified polymorphic DNA (RAPD) method. Of 13 arbitrary primers screened initially, the primer designated as universal rice primer-6 (URP-6) was selected for subsequent typing assays because it produced a distinctive and reproducible DNA fingerprint for a S. Gallinarum reference strain. URP-6-based RAPD analysis assigned 30 S. Gallinarum isolates into 6 types, with 26 isolates (86.6%) belonging to 2 major RAPD types. The distribution of virulence genes in S. Gallinarum isolates was examined by Southern hybridization. All tested isolates had the invasion gene, invA, the virulence plasmid gene, spvB, and the S. Enteritidis fimbrial gene, sefC. The distribution of virulence genes among S. Gallinarum isolates did not correlate with any specific RAPD type.

[Distribution of calcaneal bone density according to the mechanical strain of exercise and calcium intake in premenarcheal girls]

OBJECTIVES

The effects of exercise on bone density have been found to be inconsistent in previous studies. We conducted a cross-sectional study in premenarcheal girls to test two hypotheses to explain these inconsistencies. Firstly, "the intensity of mechanical strain, in terms of the ground reaction force(GRF), has more important effects on the bone mass at a weight-bearing site", and secondly, "calcium intake modifies the bone response to exercise".

METHODS

The areal bone mineral density was measured at the Os calcis, using peripheral dual energy X-ray absorptiometry, in 91 premenarcheal girls aged between 9 and 12 years. The intensity of mechanical strain of exercise was assessed by a self-report questionnaire and scored by the GRF as multiples of body weight, irrespective of the frequency and duration of exercise. The energy and calcium intake were calculated from the 24-hour dietary recall. An analysis of covariance(ANCOVA) was used to determine the interaction and main effects of exercise and calcium on the bone density, after adjusting for age, weight, height and energy intake.

RESULTS

The difference in the bone density between moderate and low impact exercise was more pronounced in the high than low calcium intake group. The bone density for moderate impact exercise and high calcium intake was significantly higher than that for low impact exercise (p=0.046) and low calcium intake, after adjusting for age, weight, height and energy intake.

CONCLUSIONS

Our study suggests that the bone density at a weight-bearing site is positively related to the intensity of mechanical loading exercise, and the calcium intake may modify the bone response to exercise at the loaded site in premenarcheal girls.

The cortical shell architecture of human cervical vertebral bodies

STUDY DESIGN

An anatomic study of cervical vertebral bodies.

OBJECTIVES

To provide quantitative information on the cortical shell architecture of the middle and lower cervical vertebral bodies.

SUMMARY OF BACKGROUND DATA

Some external dimensions have been measured, but little quantitative data exists for the cortical shell architecture of the vertebral bodies of the cervical spine.

METHODS

Twenty-one human cervical vertebral bodies (C3-C7) were sectioned along parasagittal planes into five 1.7-mm thin slices for each vertebra. Radiographs of each slice were digitized, and external and internal dimensions were measured. Averages and standard deviations were computed. Single factor analysis of variance was used to determine significant (P < 0.05) differences between the vertebral levels.

RESULTS

The superior endplate was thickest in the posterior region (range 0.74-0.89 mm) and thinnest in the anterior region (range 0.44-0.56 mm). The inferior endplate was thickest in the anterior region (range 0.61-0.81 mm) and thinnest in the posterior region (range 0.49-0.62 mm). In the central region, the superior endplate (range 0.42-0.58 mm) was thinner than the inferior endplate (range 0.53-0.64 mm). Variation with vertebral level was dependent on the dimension studied.

CONCLUSIONS

Comprehensive quantitative anatomic data of the middle and lower cervical vertebral bodies have been obtained. This may be useful in improving the understanding of the three-column and other vertebral-fracture theories, the fidelity of the finite element models of cervical spine, and the designs of surgical instrumentation.

Effect of hormone replacement therapy on nitric oxide bioactivity and monocyte chemoattractant protein-1 levels

BACKGROUND

Vascular inflammation plays an important role in the pathogenesis of atherosclerosis. We investigated the effect of hormone replacement therapy (HRT) on vasomotor function and monocyte chemoattractant protein (MCP)-1 levels, an important serological marker of inflammation.

METHODS

We administered micronized progesterone (MP) 200 mg for 10 days with conjugated equine estrogen (CEE) 0.625 mg for 25 days and remaining 5 days off cyclically during 2 months to 20 healthy postmenopausal women (PMW). We measured NO bioactivity and plasma levels of MCP-1 before and after HRT in 20 PMW. And we measured plasma levels of MCP-1 in each 20 subjects of premenopausal women, men <50, and men >50 years, respectively.

RESULTS

MP combined with CEE significantly improved the percent flow-mediated dilator response to hyperemia relative to baseline measurements (P<0.001). PMW receiving HRT had lower levels of MCP-1 than those not receiving HRT (121+/-38 versus 146+/-44 pg/ml, P<0.001). In all comparisons, subjects with high estrogen status had significantly lower MCP-1 levels than subjects with low estrogen status (P<0.001 by ANOVA). Premenopausal women had lower levels of MCP-1 than men of a similar age (106+/-14 versus 164+/-40 pg/ml, P<0.001). PMW not receiving HRT had similar levels of MCP-1 compared with men of a similar age (146+/-44 versus 143+/-29 pg/ml, P=0.816). Premenopausal women had markedly lower levels of MCP-1 than PMW not receiving HRT (106+/-14 versus 146+/-44 pg/ml, P=0.001). PMW receiving HRT had similar levels of MCP-1 compared with premenopausal women (121+/-38 versus 106+/-14 pg/ml, P=0.323).

CONCLUSION

These findings might provide at least a partial explanation for the protection against cardiovascular disease experienced by premenopausal women, and the loss of that protection following menopause.

Vascular effects of estrogen in type II diabetic postmenopausal women

OBJECTIVES

We assessed the effects of estrogen on vascular dilatory and other homeostatic functions potentially affected by nitric oxide (NO)-potentiating properties in type II diabetic postmenopausal women.

BACKGROUND

There is a higher cardiovascular risk in diabetic women than in nondiabetic women. This would suggest that women with diabetes do not have the cardioprotection associated with estrogen.

METHODS

We administered placebo or conjugated equine estrogen, 0.625 mg/day for 8 weeks, to 20 type II diabetic postmenopausal women in a randomized, double-blinded, placebo-controlled, cross-over design.

RESULTS

Compared with placebo, estrogen tended to lower low-density lipoprotein (LDL) cholesterol levels by 15 +/- 23% (p = 0.007) and increase high-density lipoprotein (HDL) cholesterol levels by 8 +/- 16% (p = 0.034). Thus, the ratio of LDL to HDL cholesterol levels significantly decreased with estrogen, by 20 +/- 24%, as compared with placebo (p = 0.001). Compared with placebo, estrogen tended to increase triglyceride levels by 16 +/- 48% and lower glycosylated hemoglobin levels by 3 +/- 13% (p = 0.295 and p = 0.199, respectively). However, estrogen did not significantly improve the percent flow-mediated dilatory response to hyperemia (17 +/- 75% vs. placebo; p = 0.501). The statistical power to accept our observation was 81.5%. Compared with placebo, estrogen did not significantly change E-selectin, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, monocyte chemoattractant protein-1 or matrix metalloproteinase-9 levels. Compared with placebo, estrogen tended to decrease tissue factor antigen and increase tissue factor activity levels by 7 +/- 46% and 5 +/- 34%, respectively (p = 0.321 and p = 0.117, respectively) and lower plasminogen activator inhibitor-1 levels by 16 +/- 31% (p = 0.043).

CONCLUSIONS

The effects of estrogen on endothelial, vascular dilatory and other homeostatic functions were less apparent in type II diabetic postmenopausal women, despite the beneficial effects of estrogen on lipoprotein levels.

Non-lipid effects of statin on hypercholesterolemic patients established to have coronary artery disease who remained hypercholesterolemic while eating a step-II diet

BACKGROUND

Results of clinical trials of statin therapy demonstrate that an improvement in incidence of cardiovascular end points and coronary stenosis can be achieved. The beneficial effects of statins on clinical events may involve nonlipid mechanisms that affect endothelial function, such as inflammatory responses, formation of thrombi, and stabilization of plaque.

OBJECTIVE

To investigate levels of serologic markers, which may be useful surrogates for activity of vascular disease after administration of statin.

METHODS

We administered 20-40 mg simvastatin daily for 14 weeks to 13 patients established to have coronary artery disease who remained hypercholesterolemic during step-II diet therapy.

RESULTS

Administration of simvastatin significantly lowered lipoprotein levels and the low: high-density lipoprotein cholesterol level ratio and apolipoprotein B:A-I level ratio compared with pretreatment values (P < 0.01). Administration of simvastatin significantly lowered plasma levels of matrix metalloproteinase-9 (MMP-9) and monocyte chemoattractant protein-I [33+/-46 and 13+/-19%, respectively (P = 0.027 and 0.020, respectively)]. Furthermore, administration of simvastatin tended to lower plasma levels of plasminogen activator inhibitor type-1 and tumor necrosis factor-alpha [by 20+/-44 and 13+/-29%, respectively (P= 0.066 and 0.110, respectively)]. There were significant inverse correlations between pretreatment levels of MMP-9 and the degree of change in those levels after administration of simvastatin (r = -0.714, P= 0.005). However, there was no significant correlation between levels of lipoprotein and levels of MMP-9, monocyte chemoattractant protein-I, and plasminogen activator inhibitor type-1 during administration of simvastatin.

CONCLUSIONS

Our current data support the hypothesis that nonlipid mechanisms elicited by administration of simvastatin contribute to the decrease in incidence of cardiovascular events and explain the early clinical benefit observed in clinical trials, independent of changes in levels of lipoprotein.

Vascular effects of synthetic or natural progestagen combined with conjugated equine estrogen in healthy postmenopausal women

BACKGROUND

Synthetic, not natural, progestagen may negate the favorable effects of estrogen. Nonetheless, observational studies report no differences in risk for clinical cardiovascular events between users of unopposed estrogen and users of estrogen combined with synthetic progestin.

METHODS AND RESULTS

In a double-blind study, we randomly assigned 20 healthy postmenopausal women to micronized progesterone (MP) 200 mg or medroxyprogesterone acetate (MPA) 10 mg for 10 days with conjugated equine estrogen (CEE) 0.625 mg for 25 days and the remaining 5 days off cyclically during 2 months, followed by crossover to the alternate therapy. CEE+MP and CEE+MPA significantly improved the percent flow-mediated dilator response to hyperemia relative to baseline measurements (P=0.004 by ANOVA) by a similar degree (P=0.863). Both therapies significantly decreased E-selectin, intercellular adhesion molecule (ICAM)-1, and vascular cell adhesion molecule (VCAM)-1 levels from baseline values (P<0.001, P=0.048, and P=0.016 by ANOVA, respectively) by a similar degree (P=0.977 for ICAM-1 and P=0.541 for VCAM-1, respectively). CEE+MPA decreased E-selectin levels more than CEE+MP did (P=0.040). Both therapies significantly decreased monocyte chemoattractant protein-1 levels from baseline values (P<0.005 by ANOVA) by a similar degree (P=0.194). Both therapies significantly decreased tissue factor antigen and increased tissue factor activity levels from baseline values (P=0.003 and P<0.001 by ANOVA, respectively) by a similar degree (P=0.652 for antigen and P=0.173 for activity). Both therapies significantly lowered plasma plasminogen activator inhibitor-1 levels from baseline values (P<0.001 by ANOVA) by a similar degree (P=0.533).

CONCLUSIONS

CEE+MP and CEE+MPA provide similar improvement in endothelium-dependent vasodilator responsiveness and effects on markers of inflammation, hemostasis, and fibrinolysis inhibition in healthy postmenopausal women.

Efficacy of heparin-coated stent in early setting of acute myocardial infarction

Primary stenting has been reported to be superior to balloon percutaneous transluminal coronary angioplasty (PTCA) in acute myocardial infarction (AMI) for recurrent ischemia, target lesion revascularization, and restenosis. However, concerns about early reocclusion or thrombosis after stenting in the very thrombotic environment of acute myocardial infarction still remain. Therefore, postprocedural short-term heparin or GpII(b)/III(a) receptor blockades has been used. The aim of our study was to evaluate the safety, feasibility, and long-term efficacy of heparin-coated stent in the early setting of AMI without postprocedural heparin or GpII(b)/III(a) receptor blockade infusion. We studied 102 consecutive patients presenting to cardiac catheterization laboratory < or = 6 hr from the onset of chest pain. No patients who were implanted with heparin-coated stents received heparin or GpII(b)/III(a) receptor blockade infusion after the procedures, not even patients who showed an angiographically large thrombus burden before stenting. Patients were evaluated for clinical endpoints at 30 days and 6 months. Coronary angiography was required for all patients at 2 weeks and 6 months after the procedure. Angiographic and procedural successes were 100% and 98%, respectively. Two patients (2%) died of heart failure without evidence of reocclusion of stented vessel during the hospitalization and 4 (4%) additional patients died of refractory heart failure within the first 6 months. Major bleeding complication occurred in one patient (1%). Recurrent myocardial infarction developed in one patient at 4 months. Early angiographic follow up at 2 weeks was performed in 88% of all patients, none of whom showed thrombotic stent occlusion. Six-month angiographic follow-up was completed in 71%(64/91) of eligible patients and binary restenosis was present in 17.2% of stented vessels. Eight(8%) patients underwent repeat PTCA. Cardiac event-free survival rate at 6 months was 86.3%. This study demonstrates that heparin-coated stents are safe in the early setting of acute myocardial infarction and no additional heparin infusion after stenting is necessary, which may reduce bleeding complications. Angiographic restenosis rate compares favorably to the binary restenosis rate from other studies with uncoated stents.

Variant angina with a strong spasmodic trait

A 55-year-old man came to the hospital because of chest pain, mostly occurring in the early morning at rest. He had to get isosorbide dinitrate intravenously with continuous infusion. Following ergonovine provocation test, total occlusion of mid-left anterior descending artery was identified with marked elevation of ST segment as exercise test showed despite isosorbide dinitrate.

The role of laparoscopy in the diagnosis and treatment of peritoneal carcinomatosis: a case report

A patient presented with deep venous thrombosis and an elevated CA-125 level, but normal pelvic ultrasound and abdominal and pelvic CT scans. Laparoscopy revealed diffuse carcinomatosis and a diagnosis of stage IIIc, poorly differentiated epithelial ovarian carcinoma was made. Laparoscopy may provide an alternative means of diagnosis when conventional imaging fails, and may facilitate the placement of catheters for subsequent intraperitoneal therapy.

The role of chemotherapy and prophylactic bilateral oophorectomy in a case of colorectal adenocarcinoma with ovarian metastases

A 66-year-old female presented with a large abdominal mass and accompanying systemic complaints of abdominal pain, constipation. and fever. On exploratory laparotomy, the mass was found to be a moderately differentiated adenocarcinoma of the sigmoid colon with metastasis to the left ovary. A primary colorectal carcinoma that has metastasized to the ovaries can be difficult to distinguish clinically from an advanced primary ovarian tumor. Histology and tumor markers are currently the most useful tools available in making an accurate diagnosis. If the nature of the primary tumor is uncertain and the initial response to chemotherapy is poor, the patient's prognosis will also he poor. Though controversy exists regarding the role of prophylactic bilateral oophorectomy during resection for primary colorectal cancer, later confusion can be avoided by performing this procedure when the colorectal carcinoma is first diagnosed. However the possibility of a concurrent primary ovarian tumor must not be overlooked.

Both V(D)J recombination and radioresistance require DNA-PK kinase activity, though minimal levels suffice for V(D)J recombination

DNA-dependent protein kinase (DNA-PK) is utilized in both DNA double-strand break repair (DSBR) and V(D)J recombination, but the mechanism by which this multiprotein complex participates in these processes is unknown. To evaluate the importance of DNA-PK-mediated protein phosphorylation in DSBR and V(D)J recombination, we assessed the effects of the phosphatidyl inositol 3-kinase inhibitor wortmannin on the repair of ionizing radiation-induced DNA double-strand breaks and V(D)J recombination in the V(D)J recombinase inducible B cell line HDR37. Wortmannin radiosensitized HDR37, but had no affect on V(D)J recombination despite a marked reduction in DNA-PK activity. On the other hand, studies with mammalian expression vectors for wild-type human DNA-PK catalytic subunit (DNA-PKcs) and a kinase domain mutant demonstrated that only the kinase active form of DNA-PKcs can reconstitute DSBR and V(D)J recombination in a DNA-PKcs-deficient cell line (Sf19), implying that DNA-PKcs kinase activity is essential for both DSBR and V(D)J recombination. These apparently contradictory results were reconciled by analyses of cell lines varying in their expression of recombinant wild-type human DNA-PKcs. These studies establish that minimal DNA-PKcs protein levels are sufficient to support V(D)J recombination, but insufficient to confer resistance to ionizing radiation.

Internal morphology of human cervical pedicles

STUDY DESIGN

The internal architecture of cervical spine pedicles was investigated by thin sectioning and digitization of radiographic images.

OBJECTIVES

To provide quantitative information on the internal dimensions and cortical shell thicknesses of the middle and lower cervical pedicles.

SUMMARY OF BACKGROUND DATA

Although there have been a number of studies presenting data on the external dimensions of the cervical pedicle, little is known regarding its internal architecture and cortical shell thickness along the pedicle axis.

METHODS

Twenty-five human cervical vertebrae (C3-C7) were secured to a thin-sectioning machine to produce three 0.7-mm-thick pedicle slices along its axis. Plain radiographs of the pedicle slices were scanned and digitized to facilitate measurement of the internal dimensions. Computer software was specifically developed to determine the external dimensions (i.e., pedicle height and width) and the internal dimensions (i.e., cortical shell thicknesses of the superior, inferior, lateral, and medial walls and the cancellous core height and width) of cervical pedicles.

RESULTS

Superior and inferior wall cortical thicknesses of pedicle thin slices were similar, whereas the lateral wall cortical thickness was significantly smaller than the medial wall thickness. The medial cortical shell (average value range: 1.2-2.0 mm) was measured to be 1.4 to 3.6 times as thick as the lateral cortical shell (average value range: 0.4-1.1 mm). When medial and lateral cortical thicknesses were normalized for external dimensions, the combined cortical shell thickness was thinnest at C7 (average value range: 18. 6-25.6% of the external width), and this result was statistically significant when compared with other vertebral levels.

CONCLUSIONS

The cervical pedicle is a complex, three-dimensional structure exhibiting extensive variability in internal morphology. Characteristics of the cervical pedicle at different spinal levels must be noted before transpedicular screw fixation.

Analyses of TCRB rearrangements substantiate a profound deficit in recombination signal sequence joining in SCID foals: implications for the role of DNA-dependent protein kinase in V(D)J recombination

We reported previously that the genetic SCID disease observed in Arabian foals is explained by a defect in V(D)J recombination that profoundly affects both coding and signal end joining. As in C.B-17 SCID mice, the molecular defect in SCID foals is in the catalytic subunit of the DNA-dependent protein kinase (DNA-PKCS); however, in SCID mice, signal end resolution remains relatively intact. Moreover, recent reports indicate that mice that completely lack DNA-PKCS also generate signal joints at levels that are indistinguishable from those observed in C.B-17 SCID mice, eliminating the possibility that a partially active version of DNA-PKCS facilitates signal end resolution in SCID mice. We have analyzed TCRB rearrangements and find that signal joints are reduced by approximately 4 logs in equine SCID thymocytes as compared with normal horse thymocytes. A potential explanation for the differences between SCID mice and foals is that the mutant DNA-PKCS allele in SCID foals inhibits signal end resolution. We tested this hypothesis using DNA-PKCS expression vectors; in sum, we find no evidence of a dominant-negative effect by the mutant protein. These and other recent data are consistent with an emerging consensus: that in normal cells, DNA-PKCS participates in both coding and signal end resolution, but in the absence of DNA-PKCS an undefined end joining pathway (which is variably expressed in different species and cell types) can facilitate imperfect signal and coding end joining.

Primary and elective stenting of unprotected isolated left main coronary ostial stenosis in acute coronary syndrome

Direct surgical angioplasty or coronary artery bypass graft has been done in patients who have left main coronary ostial stenosis. Recent reports have demonstrated that stenting of unprotected left main coronary artery stenosis has been attempted as an alternative to bypass surgery in selected patients with normal LV function. We report two patients with isolated left main coronary ostial stenosis who are undergoing primary and elective stenting, respectively. Major cardiac events did not occur during a 3-month follow-up. This study suggests that stenting of isolated left main coronary ostial stenosis in acute coronary syndrome is feasible and results in excellent outcomes.

Recurrent restenosis following stent and rotational atherectomy of coronary artery stenosis in Takayasu's arteritis

We report a patient with Takayasu's arteritis who had recurrent restenosis following intracoronary bifurcation stenting of proximal left anterior descending and first diagonal arteries, and rotational atherectomy for in-stent restenosis. After all, the patient underwent coronary artery bypass grafts (CABG) and has remained asymptomatic during 3 months without damaging myocardium. We suggest that endoluminal stenting or rotational atherectomy may be an alternative treatment for the patients with coronary artery stenosis due to active Takayasu's arteritis as a therapy to postpone CABG.

Evaluation of a test for identification of Arabian horses heterozygous for the severe combined immunodeficiency trait

OBJECTIVE

To determine whether a recently developed test would correctly identify horses heterozygous for the severe combined immunodeficiency (SCID) trait.

DESIGN

Case series.

ANIMALS

17 healthy Arabian horses that had previously produced foals with SCID, 1 healthy Arabian foal whose dam and sire had produced foals with SCID, 4 foals with SCID, and 1 healthy non-Arabian foal.

PROCEDURE

DNA was extracted from leukocytes or fibroblasts, amplified by means of polymerase chain reaction, and hybridized with probes specific for the normal and mutant alleles of the catalytic subunit of DNA-dependent protein kinase, the factor whose absence is responsible for SCID in Arabian foals.

RESULTS

Amplified DNA from the healthy non-Arabian foal hybridized only to the probe specific for the normal allele, whereas amplified DNA from the 4 foals with SCID hybridized only to the probe specific for the mutant allele. Amplified DNA from the 2 stallions and 15 mares hybridized with both probes, as did amplified DNA from the healthy foal whose dam and sire had previously produced foals with SCID, indicating that these horses were all heterozygous for the SCID trait.

CLINICAL IMPLICATIONS

Results suggest that the genetic test will be useful in identifying Arabian horses heterozygous for the SCID trait and foals with SCID, provided that all Arabian horses with SCID have the same genetic mutation.

A kinase-negative mutation of DNA-PK(CS) in equine SCID results in defective coding and signal joint formation

The equine SCID defect is more severe than its murine counterpart in that SCID foals are incapable of forming either coding or signal joints, whereas SCID mice manifest normal signal joint formation. To determine the basis of this difference and whether DNA-dependent kinase, catalytic subunit (DNA-PK(CS)), is involved in signal joint formation, equine DNA-PK(CS) transcripts were cloned and sequenced from normal and SCID cell lines. In the mutant allele, a frame-shift mutation truncates the protein N terminal of the domain with homology to the phosphatidylinositol 3-kinase family resulting in complete absence of full length DNA-PK(CS) and accounting for the kinase-negative phenotype of these cells; the mutation in SCID mice allows for some DNA-PK(CS) expression. The difference in DNA-PK(CS) expression in SCID mice and foals explains the more severe phenotype of equine SCID, and definition of DNA-PK(CS) as the defect in equine SCID demonstrates that DNA-PK(CS) is required for both coding and signal joint formation.

A kinase-negative mutation of DNA-PK(CS) in equine SCID results in defective coding and signal joint formation

The equine SCID defect is more severe than its murine counterpart in that SCID foals are incapable of forming either coding or signal joints, whereas SCID mice manifest normal signal joint formation. To determine the basis of this difference and whether DNA-dependent kinase, catalytic subunit (DNA-PK(CS)), is involved in signal joint formation, equine DNA-PK(CS) transcripts were cloned and sequenced from normal and SCID cell lines. In the mutant allele, a frame-shift mutation truncates the protein N terminal of the domain with homology to the phosphatidylinositol 3-kinase family resulting in complete absence of full length DNA-PK(CS) and accounting for the kinase-negative phenotype of these cells; the mutation in SCID mice allows for some DNA-PK(CS) expression. The difference in DNA-PK(CS) expression in SCID mice and foals explains the more severe phenotype of equine SCID, and definition of DNA-PK(CS) as the defect in equine SCID demonstrates that DNA-PK(CS) is required for both coding and signal joint formation.

The N-terminal region of E2F-1 is required for transcriptional activation of a new class of target promoter

Because of its expression in numerous cells, the herpes simplex virus thymidine kinase promoter (HSV-TK) is one of the best characterized promoters. Using the HSV-TK promoter as a model system, we have defined a new mode of E2F-1 transcriptional activation which utilizes the N-terminal region of E2F-1. We demonstrate that E2F-1 strongly activated HSV-TK, but in the absence of consensus E2F DNA elements. Nonetheless, E2F-1 could bind to GC-rich elements, which were conclusively identified in classic studies of HSV-TK as SP-1 sites. Second, the transcriptional activation of HSV-TK required the entire E2F-1 protein, including the N-terminal 89 amino acids. In contrast, the N-terminal 89 amino acids of E2F-1 were dispensable for transcriptional activation through consensus E2F sites. Third, we demonstrated that S phase entry is not sufficient for activation of HSV-TK by E2F-1, while the activation through consensus E2F sites is strictly linked to the cell cycle. Taken together, the activation of HSV-TK by E2F-1 proceeds by a different mechanism directed in part through the N-terminal region of E2F-1 and may be uncoupled from the known cell cycle regulatory role.

Multiple change in E2F function and regulation occur upon muscle differentiation

We have examined regulation of the E2F transcription factor during differentiation of muscle cells. E2F regulates many genes involved in growth control and is also the target of regulation by diverse cellular signals, including the RB family of growth suppressors (e.g., the retinoblastoma protein [RB], p107, and p130). The following aspects of E2F function and regulation during muscle differentiation were investigated: (i) protein-protein interactions, (ii) protein levels, (iii) phosphorylation of the E2F protein, and (iv) transcriptional activity. A distinct E2F complex was present in differentiated cells but not in undifferentiated cells. The p130 protein was a prominent component of the E2F complex associated with differentiation. In contrast, in undifferentiated cells, the p107 protein was the prominent component in one of three E2F complexes. In addition, use of a differentiation-defective muscle line provided genetic and biochemical evidence that quiescence and differentiation are separable events. Exclusive formation of the E2F-p130 complex did not occur in this differentiation-defective line; however, E2F complexes diagnostic of quiescence were readily apparent. Thus, sole formation of the E2F-p130 complex is a necessary event in terminal differentiation. Other changes in E2F function and regulation upon differentiation include decreased phosphorylation and increased repression by E2F. These observations suggest that the regulation of E2F function during terminal differentiation may proceed through differential interaction within the RB family and/or phosphorylation.

Recent translocation of variable and diversity segments of the human immunoglobulin heavy chain from chromosome 14 to chromosomes 15 and 16

We studied the organization and origin of three orphon regions, VH-F, D5-a, and D5-b, of the human immunoglobulin heavy-chain gene using yeast artificial chromosomes. VH-F and two D5 regions were mapped to chromosome bands 16p11 and 15q11-q12, respectively, by using human/rodent somatic cell hybrids and fluorescence in situ hybridization. No D5 segments were found on chromosome 14, in contradiction to previous reports. The VH-F region consists of 7 VH segments and encompasses 160 kb of DNA. A cluster of VH segments homologous to the VH-F region orphons was found in the region 245-430 kb (V2-26 to V3-11) upstream of the JH cluster on chromosome 14. Comparison of VH sequences between the VH-F and the chromosome 14 loci indicates that the translocation of the VH-F region took place, at the earliest, 20 x 10(6) years ago. The D5-a and D5-b regions were obtained in two independent contigs. The former contains only D segments in 140 kb of DNA, while the latter carries 3 VH segments downstream of D segments in 110 kb of DNA. V54, one of these VH orphon segments, is about 95% homologous to V1-18, which is located within the putative ancestor of the VH-F region on chromosome 14. Furthermore, the region detected by two DNA probes flanking the V54 segment was found only in the proximity of V1-18 within the 0.8-Mb VH region on chromosome 14. These results suggest that the two orphon loci on chromosomes 15 and 16 may have been translocated simultaneously.

Variable regions of Ig heavy chain genes encoding antithyrotropin receptor antibodies of patients with Graves' disease

We have established EBV-transformed human B cell clones producing monoclonal antithyrotropin receptor antibodies from two patients with Graves' disease. We then isolated and characterized Ig H chain genes of 5 B cell clones with the thyrotropin-binding inhibitor Ig (TBII) activity and 4 B cell clones with the thyroid-stimulating antibody (TSAb) activity. We found that VH gene families used in the 5 TBII clones were all VH-III, although those of the four TSAb clones were diverse, including VH-II, -III, -IV, all -V. Most of VH segments used in TBII and TSAb are commonly used in other autoantibodies and fetal liver repertoire. The frequency of somatic mutations in TBII was higher than that in TSAb. Inasmuch as the same germline VH segment (V3-23) was used for both TBII and TSAb, the frequency and position of somatic mutations may be important for generation of TBII and TSAb.

Variable regions of Ig heavy chain genes encoding antithyrotropin receptor antibodies of patients with Graves' disease

We have established EBV-transformed human B cell clones producing monoclonal antithyrotropin receptor antibodies from two patients with Graves' disease. We then isolated and characterized Ig H chain genes of 5 B cell clones with the thyrotropin-binding inhibitor Ig (TBII) activity and 4 B cell clones with the thyroid-stimulating antibody (TSAb) activity. We found that VH gene families used in the 5 TBII clones were all VH-III, although those of the four TSAb clones were diverse, including VH-II, -III, -IV, all -V. Most of VH segments used in TBII and TSAb are commonly used in other autoantibodies and fetal liver repertoire. The frequency of somatic mutations in TBII was higher than that in TSAb. Inasmuch as the same germline VH segment (V3-23) was used for both TBII and TSAb, the frequency and position of somatic mutations may be important for generation of TBII and TSAb.