Nitric oxide activates metalloprotease enzymes in articular cartilage

Nitric oxide (NO.) is a multifunctional messenger molecule generated by a family of enzymes, collectively termed the nitric oxide synthases. We investigated the role of NO. in the modulation of two metal-dependent proteolytic enzymes (collagenase and stromelysin) which are activated during inflammatory and infective arthritis. The inflammatory mediators interleukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha) and the bacterial cell wall fragment endotoxin, induced both nitric oxide synthase activity and stromelysin and collagenase activity in whole cell preparations and in conditioned media from explants of bovine and human cartilage. Both NO2- (the stable end-product of NO.) and metalloprotease activity were inhibited by competitive inhibitors of nitric oxide synthase. The NO. donor, S-nitroso-N-acetyl-D,L-penicillamine (SNAP) also induced metalloprotease activity in a dose-dependent fashion. These data provide evidence that NO. plays a regulatory role in the activation of metal-dependent proteases in articular chondrocytes and cartilage.

Rabbit model for Chlamydia pneumoniae infection

A rabbit model was established for Chlamydia pneumoniae infection that may be helpful to understand the pathogenesis of disease in humans. Twelve, pathogen-free, 1-month-old New Zealand White rabbits were inoculated with 1.0 x 10(7) to 5.0 x 10(7) CFU of purified C. pneumoniae (ATCC strain VR 1310) via the nasopharynx (1 rabbit died immediately postinoculation, and 11 were available for study). Five controls were inoculated with the carrier buffer. Ten of the 11 study rabbits demonstrated serological evidence of acute infection (immunoglobulin G antibodies, 1:8 to > 1:16), with the weakest response at 7 days and the strongest response at 28 days, whereas none of the controls showed any seroconversion. Study animals were sacrificed in batches of three, on days 7, 14, 21, and 28, but controls were sacrificed on days 7 and 28. Two-thirds of the animals demonstrated evidence of bronchiolitis and pneumonia on days 7 and 14 and resolution by day 21. Two study rabbits demonstrated, on histology, early and intermediate lesions of atherosclerosis: one animal (day 7) showed the accumulation of foamy macrophages (fatty streak) in the arch of the aorta, and the other animal (day 14) showed spindle cell proliferation of smooth muscle cells (intermediate lesion). Focal periaortitis was seen in the same animal (day 7). C. pneumoniae elementary bodies were demonstrated by immunocytochemical stain in the lungs (n = 2), liver (n = 3), spleen (n = 5), and aorta (n = 2), one of which corresponded to the intermediate lesion. C. pneumoniae was cultured from the lungs (n = 2), liver (n = 2), spleen (n = 2), and aortic arch (n = 1). All histopathological, immunocytochemical, and cultural studies were negative in the controls. Hence, the rabbit provides a useful animal model for the study of C. pneumoniae infection and its complications, particularly atherosclerosis.

Diagnosis of Chlamydia trachomatis infections in men and women by testing first-void urine by ligase chain reaction

From April to September 1993, 305 men and 447 women in Hamilton, Canada, consented to the collection of a urethral or cervical swab, respectively, for culture and 20 ml of first-void urine (FVU) for testing by the enzyme immunoassay Chlamydiazyme and by ligase chain reaction (LCR) in the form of a kit from Abbott Laboratories called LCx Chlamydia trachomatis. Evaluation of test performance with each specimen was calculated on the basis of an expanded "gold standard" of a patient found to be positive by culture or by a confirmed nonculture test. By using this expanded standard, the prevalence of infection was determined to be 6% (27/447) for the women and 18.4% (56/305) for the men. LCR testing of FVU in both studies was the most sensitive approach (96%). The performance of Chlamydiazyme was as follows: cervical swab, 78.3% sensitivity; female FVU, 37% sensitivity; and male FVU, 67.9% sensitivity. Culture was the least sensitive approach to diagnosis: female cervix, 55.6%; and male urethra, 37.5%. LCR testing of FVU from men or women diagnosed the greatest number of genitourinary tract infections with no false positives.

Urine specimens from pregnant and nonpregnant women inhibitory to amplification of Chlamydia trachomatis nucleic acid by PCR, ligase chain reaction, and transcription-mediated amplification: identification of urinary substances associated with inhibition and removal of inhibitory activity

The presence of endogenous amplification inhibitors in urine may produce false-negative results for the detection of Chlamydia trachomatis nucleic acids by tests such as PCR, ligase chain reaction (LCR), and transcription-mediated amplification (TMA). Consecutive urine specimens from 101 pregnant women and 287 nonpregnant women submitted for urinalysis were processed for C. trachomatis detection. Aliquots were spiked with the equivalent of one C. trachomatis elementary body and were tested by three commercial assays: AMPLICOR CT/NG, Chlamydia LCX, and Chlamydia TMA. The prevalence of inhibitors resulting in complete inhibition of amplification was 4.9% for PCR, 2.6% for LCR, and 7.5% for TMA. In addition, all three assays were partially inhibited by additional urine specimens. Only PCR was more often inhibited by urine from pregnant women than by urine from nonpregnant women (9.9 versus 3.1%; P = 0.011). A complete urinalysis including dipstick and a microscopic examination was performed. Logistic regression analysis revealed that the following substances were associated with amplification inhibition: beta-human chorionic gonadotropin (odds ratio [OR], 3.3) and crystals (OR, 3.3) for PCR, nitrites for LCR (OR, 14.4), and hemoglobin (OR, 3.3), nitrites (OR, 3.3), and crystals (OR, 3.3) for TMA. Aliquots of each inhibitory urine specimen were stored at 4 and -70 degreesC overnight or were extracted with phenol-chloroform and then retested at dilutions of 1:1, 1:4, and 1:10. Most inhibition was removed by storage overnight at 4 or -70 degreesC and a dilution of 1:10 (84% for PCR, 100% for LCR, and 92% for TMA). Five urine specimens (three for PCR and two for TMA) required phenol-chloroform extraction to remove inhibitors. The results indicate that the prevalence of nucleic acid amplification inhibitors in female urine is different for each technology, that this prevalence may be predicted by the presence of urinary factors, and that storage and dilution remove most of the inhibitors.

Nitric oxide modulates fracture healing

The role of the messenger molecule nitric oxide has not been evaluated in fracture healing. NO is synthesized by three kinds of nitric oxide synthase (NOS): inducible NOS (iNOS), endothelial (eNOS), and neuronal (bNOS). We evaluated the role of these enzymes in a rat femur fracture-healing model. There was no messenger RNA (mRNA) expression, immunoreactivity, or enzymatic activity for NOS in unfractured femoral cortex. After fracture, however, mRNA, protein, and enzymatic activity for iNOS were identified in the healing rat femoral fracture callus, with maximum activity on day 15. The mRNA expression for eNOS and bNOS was induced slightly later than for iNOS, consistent with a temporal increase in calcium-dependent NOS activity that gradually increased up to day 30. mRNA expression for the three NOS isoforms also was found in six of six human fracture callus samples. To study the effect of suppression of NO synthesis on fracture healing, an experimental group of rats was fed an NOS inhibitor, L-nitroso-arginine methyl ester (L-NAME), and the control group was fed its inactive enantiomer, D-nitroso-arginine methyl ester (D-NAME). An 18% (p < or = 0.01) decrease in cross-sectional area and a 45% (p < or = 0.05) decrease in failure load were observed in the NOS-inhibited group on day 24 after fracture. Furthermore, the effect of NO supplementation to fracture healing was studied by delivering NO to the fracture site using carboxybutyl chitosan NONOate locally. On day 17 after fracture, there was a 30% (p < or = 0.05) increase in cross-sectional area in the NO-donor group compared with the NOS inhibition group. These results show for the first time that NO is expressed during fracture healing in rats and in humans, that suppression of NOS impairs fracture healing, and that supplementation of NO can reverse the inhibition of healing produced by NOS inhibitors.

Modulation of tendon healing by nitric oxide

Nitric oxide (NO) is a small, diffusible free radical that is generated from L-arginine by a family of enzymes, collectively termed the nitric oxide synthases. We investigated the role of NO in tendon healing. NO synthase activity and immunoreactivity was absent in un-injured rat Achilles tendon. After surgical division there was a five-fold increase in NO synthase activity and immunoreactivity within the healing tendon at day 7, with a return to near baseline levels at day 14. Inhibition of NO synthase activity with oral administration of N omega-nitro-L-arginine methyl ester (L-NAME) resulted in a significant reduction in cross-sectional area (30% at day 7, p < 0.01, 50% at day 15, p < 0.001) and failure load (24% at day 7, p < 0.01) of the healing Achilles tendon constructs. Rats fed the same regimen of the enantiomer of L-NAME, (D-NAME) had normal tendon healing. These results indicate that nitric oxide synthase is induced during tendon healing and inhibition of nitric oxide synthase inhibits this tendon healing.

Nitric oxide in arthritis

Nitric oxide's (NO) involvement in arthritis was first demonstrated when levels of nitrite, a stable endproduct of NO metabolism, were shown to be elevated in serum and synovial fluid samples of rheumatoid and osteoarthritis patients. NO production by chondrocytes, its involvement in various biochemical events of cartilage metabolism, and the in vivo suppression of experimental arthritis by NO synthase inhibitors further implicated NO in arthritis. However, a conclusive role for NO in the pathogenesis of arthritis remains to be defined, in contrast to the NO-cGMP signal transduction pathway of endothelium-mediated vasodilation. It appears that NO has limited modulating effects in cartilage metabolism, with evidence for both protective and deleterious effects. Recent developments that contribute to our understanding of NO's role in arthritis are discussed.

Wireless fast-scan cyclic voltammetry to monitor adenosine in patients with essential tremor during deep brain stimulation

Essential tremor is often markedly reduced during deep brain stimulation simply by implanting the stimulating electrode before activating neurostimulation. Referred to as the microthalamotomy effect, the mechanisms of this unexpected consequence are thought to be related to microlesioning targeted brain tissue, that is, a microscopic version of tissue ablation in thalamotomy. An alternate possibility is that implanting the electrode induces immediate neurochemical release. Herein, we report the experiment performing with real-time fast-scan cyclic voltammetry to quantify neurotransmitter concentrations in human subjects with essential tremor during deep brain stimulation. The results show that the microthalamotomy effect is accompanied by local neurochemical changes, including adenosine release.

De Novo induction of atherosclerosis by Chlamydia pneumoniae in a rabbit model

Chlamydia pneumoniae, a bacterial respiratory tract pathogen, has been associated with atherosclerosis in humans. C. pneumoniae infection of the respiratory tracts of rabbits fed a noncholesterol diet induced changes of atherosclerosis of the aorta in 6 (26.1%) of 23 animals after a single inoculum at 3 months. Multiple inocula given three times within 6 weeks resulted in grade III atherosclerosis in 8 (34.8%) of 23 rabbits, with an additional 5 (21. 7%) showing increased myxoid changes in the intima-media junction and exhibiting 8 (34.8%) focal periaortitis. Control animals inoculated with carrier broth (n = 24), HEp-2 cells (n = 12), or another respiratory pathogen, Mycoplasma pneumoniae (n = 32), produced no changes of atherosclerosis after 3 months. The histological changes were dissimilar (fewer foam cells) from those of rabbits fed a 0.5% cholesterol diet but were highly similar to or indistinguishable from changes in rabbits fed a 0.15% cholesterol diet (similar to that of humans). Proinflammatory cytokines and tissue growth factors were more consistently detected in cholesterol-induced aortic lesions than those induced by C. pneumoniae. These data are compatible with de novo induction of atherogenesis by C. pneumoniae in rabbits and suggest that C. pneumoniae may be important in the pathogenesis of atherosclerosis in humans.

The effect of virtual reality cognitive training for attention enhancement

Our main goal in this research was to validate the possibility of virtual reality (VR) for attention enhancement in cognitive training program. Then, we developed some cognitive training tasks using VR technology. Thirty subjects who had little behavioral problems and social problems were randomly assigned into three groups: VR group, non-VR group, and control group. Only the VR group used the head-mounted display (HMD) and position sensor. While the VR group and non-VR group performed cognitive training, the control group received no special treatment. All participants took their eight session tasks over 2 weeks. Participants executed a continuous performance task (CPT) before and after training sessions. We found that immersive VR with cognitive training is effective for attention enhancement. Also, we confirmed that our cognitive training can improve the attention span of children and adolescents with behavioral problems and help them learn to focus on some tasks.

High-precision measurement of the W boson mass with the CDF II detector

The mass of the W boson, a mediator of the weak force between elementary particles, is tightly constrained by the symmetries of the standard model of particle physics. The Higgs boson was the last missing component of the model. After observation of the Higgs boson, a measurement of the W boson mass provides a stringent test of the model. We measure the W boson mass, M_W, using data corresponding to 8.8 inverse femtobarns of integrated luminosity collected in proton-antiproton collisions at a 1.96 tera-electron volt center-of-mass energy with the CDF II detector at the Fermilab Tevatron collider. A sample of approximately 4 million W boson candidates is used to obtain [Formula: see text], the precision of which exceeds that of all previous measurements combined (stat, statistical uncertainty; syst, systematic uncertainty; MeV, mega-electron volts; c, speed of light in a vacuum). This measurement is in significant tension with the standard model expectation.

Tracking tonic dopamine levels in vivo using multiple cyclic square wave voltammetry

For over two decades, fast-scan cyclic voltammetry (FSCV) has served as a reliable analytical method for monitoring dopamine release in near real-time in vivo. However, contemporary FSCV techniques have been limited to measure only rapid (on the order of seconds, i.e. phasic) changes in dopamine release evoked by either electrical stimulation or elicited by presentation of behaviorally salient stimuli, and not slower changes in the tonic extracellular levels of dopamine (i.e. basal concentrations). This is because FSCV is inherently a differential method that requires subtraction of prestimulation tonic levels of dopamine to measure phasic changes relative to a zeroed baseline. Here, we describe the development and application of a novel voltammetric technique, multiple cyclic square wave voltammetry (M-CSWV), for analytical quantification of tonic dopamine concentrations in vivo with relatively high temporal resolution (10 s). M-CSWV enriches the electrochemical information by generating two dimensional voltammograms which enable high sensitivity (limit of detection, 0.17 nM) and selectivity against ascorbic acid, and 3,4-dihydroxyphenylacetic acid (DOPAC), including changes in pH. Using M-CSWV, a tonic dopamine concentration of 120 ± 18 nM (n = 7 rats, ± SEM) was determined in the striatum of urethane anethetized rats. Pharmacological treatments to elevate dopamine by selectively inhibiting dopamine reuptake and to reduce DOPAC by inhibition of monoamine oxidase supported the selective detection of dopamine in vivo. Overall, M-CSWV offers a novel voltammetric technique to quantify levels and monitor changes in tonic dopamine concentrations in the brain to further our understanding of the role of dopamine in normal behavior and neuropsychiatric disorders.

Confirmatory polymerase chain reaction testing for Chlamydia trachomatis in first-void urine from asymptomatic and symptomatic men

First-void urine specimens from 683 men (592 without symptoms) were tested for Chlamydia trachomatis by a polymerase chain reaction (PCR) with KL1 and KL2 plasmid primers and by a Chlamydiazyme enzyme immunoassay (EIA). Thirty-seven specimens were confirmed to be positive by using the EIA blocking reagent and a second set of plasmid primers (T1 and T2). By comparing unconfirmed PCR results (KL1 and KL2 primers only) with the blocked Chlamydiazyme EIA results, the sensitivity and specificity of PCR were 100% (37 of 37 specimens) and 99.5% (643 of 646 specimens), respectively. Three additional specimens were negative by EIA but positive by PCR and were confirmed to be positive with primers T1 and T2. Two of the three specimens were from men with symptoms. The confirmatory PCR assay performed equally well in detecting positive specimens from symptomatic (31 of 31) and asymptomatic (9 of 9) men. Comparison of confirmatory testing of first-void urine specimens by PCR and EIA showed that PCR was 100% sensitive (40 of 40 specimens) and that the EIA was 92.5% sensitive (37 of 40 specimens) but that the assays were equally specific (100%).

Nitric oxide enhances cyclooxygenase activity in articular cartilage

Nitric oxide (NO) is a small messenger molecule synthesized by a family of enzymes, the nitric oxide synthases. Cyclooxygenases are a group of proinflammatory enzymes that release prostaglandins including prostaglandin E2 (PGE2). Both nitric oxide synthase and cyclooxygenase are involved in the inflammatory cascade of arthritis. However, the relationship between these two enzymes and their products has not been explored in articular cartilage. Here we show that in cultured bovine chondrocytes and explants of human osteoarthritic cartilage both nitric oxide synthase and cyclooxygenase activities were induced by the inflammatory mediators, lipopolysaccharide, and interleukin-1 beta or tumor necrosis factor-alpha. When nitric oxide synthase activity was inhibited, PGE2, synthesis was inhibited. NO donors also induced PGE2 synthesis and NO scavengers inhibited cyclooxygenase activity. Taken together, these results support the concept that PGE2 synthesis is directly related to NO formation and that NO may modulate cyclooxygenase activity in articular cartilage.

Development of virtual reality proprioceptive rehabilitation system for stroke patients

In this study, the virtual reality (VR) proprioception rehabilitation system was developed for stroke patients to use proprioception feedback in upper limb rehabilitation by blocking visual feedback. To evaluate its therapeutic effect, 10 stroke patients (onset>3 month) trained proprioception feedback rehabilitation for one week and visual feedback rehabilitation for another week in random order. Proprioception functions were checked before, a week after, and at the end of training. The results show the click count, error distance and total error distance among proprioception evaluation factors were significantly reduced after proprioception feedback training compared to visual feedback training (respectively, p=0.005, p=0.001, and p=0.007). In addition, subjects were significantly improved in conventional behavioral tests after training. In conclusion, we showed the effectiveness and possible use of the VR to recover the proprioception of stroke patients.

Monitoring In Vivo Changes in Tonic Extracellular Dopamine Level by Charge-Balancing Multiple Waveform Fast-Scan Cyclic Voltammetry

Dopamine (DA) modulates central neuronal activity through both phasic (second to second) and tonic (minutes to hours) terminal release. Conventional fast-scan cyclic voltammetry (FSCV), in combination with carbon fiber microelectrodes, has been used to measure phasic DA release in vivo by adopting a background subtraction procedure to remove background capacitive currents. However, measuring tonic changes in DA concentrations using conventional FSCV has been difficult because background capacitive currents are inherently unstable over long recording periods. To measure tonic changes in DA concentrations over several hours, we applied a novel charge-balancing multiple waveform FSCV (CBM-FSCV), combined with a dual background subtraction technique, to minimize temporal variations in background capacitive currents. Using this method, in vitro, charge variations from a reference time point were nearly zero for 48 h, whereas with conventional background subtraction, charge variations progressively increased. CBM-FSCV also demonstrated a high selectivity against 3,4-dihydroxyphenylacetic acid and ascorbic acid, two major chemical interferents in the brain, yielding a sensitivity of 85.40 ± 14.30 nA/μM and limit of detection of 5.8 ± 0.9 nM for DA while maintaining selectivity. Recorded in vivo by CBM-FSCV, pharmacological inhibition of DA reuptake (nomifensine) resulted in a 235 ± 60 nM increase in tonic extracellular DA concentrations, while inhibition of DA synthesis (α-methyl-dl-tyrosine) resulted in a 72.5 ± 4.8 nM decrease in DA concentrations over a 2 h period. This study showed that CBM-FSCV may serve as a unique voltammetric technique to monitor relatively slow changes in tonic extracellular DA concentrations in vivo over a prolonged time period.

Antibiotics in coastal aquaculture waters: Occurrence and elimination efficiency in oxidative water treatment processes

The influents and effluents of coastal flow-through aquacultures in Korea were monitored for four selected antibiotics (amoxicillin-AMX, florfenicol-FLO, oxolinic acid-OXO, and oxytetracycline-OTC). A number of 177 samples were obtained from 16 aquaculture facilities for a monitoring period of two years. OTC was detected in 93 samples with a median concentration of 116 ng/L. OXO, FLO, and AMX were also detected in 36, 34, and 22 samples with median concentrations of 90, 44, and 63 ng/L, respectively. After antibiotics were applied to fish tanks, the aquaculture effluents were found to contain antibiotics up to several hundred μg/L, indicating that some control measures are required. Bench-scale experiments showed that chlorine and ozone fully eliminated AMX and OTC but not FLO at ≤2 mg/L of oxidant dosage. Reactive halogen species formed in the marine water matrix enhanced the antibiotic degradation. UV₂₅₄ most effectively eliminated FLO, achieving 60-70 % elimination at 1000 mJ/cm² of UV fluence. Sequential use of chlorine followed by UV₂₅₄ demonstrated significant elimination of all four selected antibiotics. The obtained kinetic information for the reactions of these oxidants and UV with the antibiotics and marine aquaculture water constituents could be useful for designing and optimizing the aquaculture water treatment processes.

A proton MRSI study of brain N-acetylaspartate level after 12 weeks of citalopram treatment in drug-naive patients with obsessive-compulsive disorder

OBJECTIVE

Reductions in the level of N-acetylaspartate within subcortical structures of patients with obsessive-compulsive disorder (OCD) have been reported in several studies. However, there have been, as yet, no reports regarding N-acetylaspartate levels in the prefrontal cortex of adult drug-naive OCD patients. The authors used proton magnetic resonance spectroscopic imaging ((1)H-MRSI) to investigate regional N-acetylaspartate level abnormalities and changes after 12 weeks of pharmacotherapy with citalopram in drug-naive OCD patients.

METHOD

Thirteen drug-naive OCD patients and 13 age- and sex-matched healthy comparison subjects were included in this study. N-acetylaspartate levels (obtained from ratios of N-acetylaspartate with creatine, choline, and creatine plus choline) in the prefrontal cortex, parietal cortex, anterior cingulate, posterior cingulate, frontal white matter, and parietal white matter were measured by (1)H-MRSI. In OCD patients, measurements were taken before and after 12 weeks of citalopram treatment. Correlations between N-acetylaspartate concentrations in regions of interest and clinical measures were also assessed.

RESULTS

Drug-naive OCD patients exhibited significantly lower N-acetylaspartate levels in the prefrontal cortex, frontal white matter, and anterior cingulate at baseline than did comparison subjects. Significant increases in N-acetylaspartate level were detected in the prefrontal cortex and frontal white matter in OCD patients after 12 weeks of citalopram treatment.

CONCLUSIONS

These data suggest that reductions in neuronal viability occur in the frontal region of OCD patients and that these reductions may be partly reversible.

Characteristics of the m2000 automated sample preparation and multiplex real-time PCR system for detection of Chlamydia trachomatis and Neisseria gonorrhoeae

We evaluated a new real-time PCR-based prototype assay for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae developed by Abbott Molecular Inc. This assay is designed to be performed on an Abbott m2000 real-time instrument system, which consists of an m2000sp instrument for sample preparation and an m2000rt instrument for real-time PCR amplification and detection. The limit of detection of this prototype assay was determined to be 20 copies of target DNA for both C. trachomatis and N. gonorrhoeae, using serially diluted linearized plasmids. No cross-reactivity could be detected when 55 nongonococcal Neisseria isolates and 3 non-C. trachomatis Chlamydia isolates were tested at 1 million genome equivalents per reaction. Concordance with the Roche Amplicor, BDProbeTec ET, and Gen-Probe APTIMA Combo 2 tests was assessed using unlinked/deidentified surplus clinical specimens previously analyzed with these tests. For C. trachomatis, concordance for positive results ranged from 93.7% to 100%, while concordance for negative results ranged from 98.2% to 100%. For N. gonorrhoeae, concordance for positive and negative results ranged from 91.4% to 100% and 99.3% to 100%, respectively. A workflow analysis of the prototype assay was conducted to obtain information on throughput under laboratory conditions. At 48 samples/run, the time to first result for both C. trachomatis and N. gonorrhoeae was 4.5 h. A total of 135 patient specimens could be analyzed in 8.9 h, with 75 min of hands-on time. This study demonstrated the technical and clinical feasibility of the new Abbott real-time PCR C. trachomatis/N. gonorrhoeae assay.

Observation of the narrow state X(3872)-->J/psipi+pi- in pp collisions at sqaure root of s=1.96 TeV

We report the observation of a narrow state decaying into J/psipi+pi- and produced in 220 pb(-1) of p p-bar collisions at =1.96 Tesqaure root of sV in the CDF II experiment. We observe 730+/-90 decays. The mass is measured to be 3871.3+/-0.7(stat)+/-0.4(syst) MeV/c2, with an observed width consistent with the detector resolution. This is in agreement with the recent observation by the Belle Collaboration of the X(3872) meson.

Urinary inhibitors of polymerase chain reaction and ligase chain reaction and testing of multiple specimens may contribute to lower assay sensitivities for diagnosing Chlamydia trachomatis infected women

In a comparison of commercial ligase chain reaction (LCR; Abbott) and polymerase chain reaction (PCR; Roche) assays, measuring plasmid genes of Chlamydia trachomatis, some specimens were found to be negative by either or both assays but positive in traditional culture or antigen detection tests. Of 767 women, 35 were found to be infected by cervical or urine testing. Twenty three specimens from 16 women may have contained inhibitors in six cervical swabs (CS) and 15 first void urines (FVU). By performing dilution and 'spiking' experiments on five FVU, inhibitors of PCR, LCR or both, which disappeared by dilution, were demonstrated. Confirmatory assays were used which amplified segments of the major outer membrane gene by PCR or LCR. When comparisons of assays were made on a single specimen type, the sensitivities of the amplification assays, compared to an expanded reference standard, were as follows: on CS, PCR was 93.8% (30/32) and LCR was 96.9% (31/32); on FVU, PCR was 76.6% (23/30) and LCR was 93.3% (28/30). When a combined calculation was made to determine the ability of the assays to detect patients infected in the cervix or urethra by testing FVU, the sensitivities dropped to 71.4% (25/35) for PCR and 80.0% (28/35) for LCR: CS sensitivity was 88.6% (31/35) for both amplified tests. There were two CS and five FVU false-positives by PCR which reduced to one CS and three FVU in the combined analysis. There were no false-positives by LCR. Inhibitors and low levels of chlamydial plasmid nucleic acids may have contributed to lower than expected sensitivities, suggesting a possible need for internal positive controls, especially for PCR, when testing urine. More studies with multiple sampling and more than one amplification assay are needed to confirm these findings and to identify and remove inhibitors of amplification assays.

Ability of commercial ligase chain reaction and PCR assays to diagnose Chlamydia trachomatis infections in men by testing first-void urine

A total of 287 men (37.6% with symptoms of urethritis) attending a hospital-based sexually transmitted disease clinic had urethral swabs tested by culture and by direct fluorescent-antibody assay. First-void urine (FVU) was tested for Chlamydia trachomatis by commercially available ligase chain reaction (LCR) and PCR assays. By using an expanded reference standard, 35 men (12.2%) were found to be positive. By performing LCR and PCR, the infection prevalence was found to be approximately twice (11.5 and 12.2%, respectively) that determined swab testing. The sensitivity values were 94.3% for LCR and 100% for PCR. One of the two positive specimens missed by LCR contained inhibitors. PCR produced five false-positive results and LCR produced one.

A data-driven artificial intelligence model for remote triage in the prehospital environment

In a mass casualty incident, the factors that determine the survival rate of injured patients are diverse, but one of the key factors is the time for triage. Additionally, the main factor that determines the time of triage is the number of medical personnel. However, when relying on a small number of medical personnel, the ability to increase survivability is limited. Therefore, developing a classification model for survival prediction that can quickly and precisely triage via wearable devices without medical personnel is important. In this study, we designed a consciousness index to substitute the factor by manpower and improved the classification accuracy by applying a machine learning algorithm. First, logistic regression analysis using vital signs and a consciousness index capable of remote monitoring through wearable devices confirmed the high efficiency of the consciousness index. We then developed a classification model with high accuracy which corresponds to existing injury severity scoring systems through the machine learning algorithms. We extracted 460,865 cases which met our criteria for developing the survival prediction from the national sample project in the national trauma databank which contains 408,316 cases of blunt injury and 52,549 cases of penetrating injury. Among the dataset, 17,918 (3.9%) cases died while the other survived. The AUCs with 95% confidence intervals (CIs) for the different models with the proposed simplified consciousness score as follows: RTS (as baseline), 0.78 (95% CI = 0.775 to 0.785); logistic regression, 0.87 (95% CI = 0.862 to 0.870); random forest, 0.87 (95% CI = 0.862 to 0.872); deep neural network, 0.89 (95% CI = 0.882 to 0.890). As a result, we confirmed the possibility of remote triage using a wearable device. It is expected that the time required for triage can be effectively reduced by using the developed classification model of survival prediction.

Role of confirmatory PCRs in determining performance of Chlamydia Amplicor PCR with endocervical specimens from women with a low prevalence of infection

The role of confirmatory PCR assays for determining the performance of Chlamydia Amplicor PCR for endocervical specimens from women with a low prevalence of infection was evaluated. An endocervical swab was collected from 770 women and tested by culture or direct fluorescent antibody (DFA) staining. A second swab was tested by Chlamydia Amplicor PCR (Roche Molecular Systems, Branchburg, N.J.). Discordant results were resolved by three confirmatory PCRs: one targeting the plasmid by using different primers and two directed to the major outer membrane protein (MOMP) gene. Of the 30 swabs that were positive by culture or DFA (3.9%), 27 were positive by Amplicor PCR. An additional five swabs were positive by Amplicor PCR but negative by culture or DFA. Both plasmid and MOMP confirmatory PCRs identified the five culture-DFA negatives and the three Amplicor negatives as true positives. The three specimens originally classified as negative by Amplicor PCR were positive on repeat Amplicor testing. After resolution of the discordant results by confirmatory PCR testing, the sensitivity of the initial Amplicor PCR was 91.4% (32 of 35 specimens), changing to 100% after storage and repeat testing. The specificity of Amplicor PCR was 100% (735 of 735 specimens). Our results demonstrated that plasmid and MOMP confirmatory PCRs worked equally well in resolving false-positive and false-negative Amplicor PCR results. Some specimens may contain inhibitors of Amplicor PCR which may disappear with time.