Impact of discontinuing isolation in a private room for patients infected or colonized with vancomycin-resistant enterococci (VRE) on the incidence of healthcare-associated VRE bacteraemia in a hospital with a predominantly shared-room setting

BACKGROUND

Isolating patients infected or colonized with vancomycin-resistant enterococci (VRE) in a private room or cohort room to prevent hospital transmission is controversial.

AIM

To evaluate the effect of a relaxed isolation policy for VRE-infected or colonized patients on healthcare-associated (HA) VRE bacteraemia in an acute care hospital with a predominantly shared-room setting.

METHODS

The incidence of HA VRE bacteraemia was compared during a private isolation era (October 2014-September 2017), a cohort isolation era (October 2017-June 2020), and a no isolation era (July 2020-June 2022). Using Poisson regression modelling, an interrupted time-series analysis was conducted to analyse level changes and trends in incidences of HA VRE bacteraemia for each era.

FINDINGS

The proportion of VRE-infected or -colonized patients staying in shared rooms increased from 18.3% in the private isolation era to 82.6% in the no isolation era (P < 0.001). There was no significant difference in the incidences of HA VRE bacteraemia between the private isolation era and the cohort isolation era (relative risk: 1.01; 95% confidence interval: 0.52-1.98; P = 0.977) or between the cohort isolation era and the no isolation era (0.99; 0.77-1.26; P = 0.903). In addition, there was no significant slope increase in the incidence of HA VRE bacteraemia between any of the eras.

CONCLUSION

In a hospital with predominantly shared rooms, the relaxation of isolation policy did not result in increased HA VRE bacteraemia, when other infection control measures were maintained.

Reduction in the acquisition rate of carbapenem-resistant Acinetobacter baumannii (CRAB) after room privatization in an intensive care unit

BACKGROUND

Acinetobacter baumannii is one of the major pathogens responsible for healthcare-associated infections, especially in intensive care units (ICUs).

AIM

To evaluate the effect of room privatization in an ICU on the acquisition of carbapenem-resistant A. baumannii (CRAB).

METHODS

Between March and August 2017, a medical ICU was renovated from a multibed bay room to single rooms. Acquisition of CRAB was compared between patients admitted to the ICU over 18 months pre-renovation (September 2015 to February 2017) and post-renovation (September 2017 to February 2019). A Cox proportional hazard model was used with adjustment for demographics and comorbidities.

FINDINGS

Of the 901 patients, who contributed 8,276 patient-days, 95 (10.5%) acquired CRAB during their ICU stay. The CRAB acquisition rate was significantly higher during the pre-renovation period (1.87 per 100 patient-days) than during the post-renovation period (0.39 per 100 patient-days) (P < 0.001). In the multivariable Cox regression model, CRAB acquisition was significantly associated with the presence of a feeding tube (adjusted hazard ratio [aHR], 6.08; 95% confidence interval [CI], 2.46-15.06; P < 0.001), continuous renal replacement therapy (aHR, 1.66; 95% CI, 1.09-2.53; P = 0.019) and admission after renovation of the ICU to single rooms (aHR, 0.23; 95% CI, 0.12-0.41; P < 0.001).

CONCLUSIONS

Renovation of ICUs to single rooms is an efficient strategy to prevent transmission of multidrug-resistant organisms and hospital-acquired infections.

Improving Concussion Education: Consensus From the NCAA-Department of Defense Mind Matters Research & Education Grand Challenge

Early disclosure of possible concussive symptoms has the potential to improve concussion-related clinical outcomes. The objective of the present consensus process was to provide useful and feasible recommendations for collegiate athletic departments and military service academy leaders about how to increase concussion symptom disclosure in their setting. Consensus was obtained using a modified Delphi process. Participants in the consensus process were grant awardees from the National Collegiate Athletic Association and Department of Defense Mind Matters Research & Education Grand Challenge and a multidisciplinary group of stakeholders from collegiate athletics and military service academies. The process included a combination of in-person meetings and anonymous online voting on iteratively modified recommendations for approaches to improve concussion symptom disclosure. Recommendations were rated in terms of their utility and feasibility in collegiate athletic and MSA settings with a priori thresholds for retaining, discarding, and revising statements. A total of 17 recommendations met thresholds for utility and feasibility and are grouped for discussion in five domains: (1) content of concussion education for athletes and MSA cadets, (2) dissemination and implementation of concussion education for athletes and military service academy cadets, (3) other stakeholder concussion education, (4) team and unit-level processes, and (5) organizational processes. Collectively, these recommendations provide a path forward for athletics departments and military service academies in terms of the behavioral health supports and institutional processes that are needed to increase early and honest disclosure of concussion symptoms and ultimately to improve clinical care outcomes.

Enhanced antimicrobial stewardship based on rapid phenotypic antimicrobial susceptibility testing for bacteraemia in patients with haematological malignancies: a randomized controlled trial

OBJECTIVES

Recently, rapid phenotypic antimicrobial susceptibility testing (AST) based on microscopic imaging analysis has been developed. The aim of this study was to determine whether implementation of antimicrobial stewardship programmes (ASP) based on rapid phenotypic AST can increase the proportion of patients with haematological malignancies who receive optimal targeted antibiotics during early periods of bacteraemia.

METHODS

This randomized controlled trial enrolled patients with haematological malignancies and at least one positive blood culture. Patients were randomly assigned 1:1 to conventional (n = 60) or rapid phenotypic (n = 56) AST. The primary outcome was the proportion of patients receiving optimal targeted antibiotics 72 hr after blood collection for culture.

RESULTS

The percentage receiving optimal targeted antibiotics at 72 hr was significantly higher in the rapid phenotypic AST group (45/56, 80.4%) than in conventional AST group (34/60, 56.7%) (relative risk (RR) 1.42, 95% confidence interval (CI) 1.09-1.83). The percentage receiving unnecessary broad-spectrum antibiotics at 72 hr was significantly lower (7/26, 12.5% vs 18/60, 30.0%; RR 0.42, 95% CI 0.19-0.92) and the mean time to optimal targeted antibiotic treatment was significantly shorter (38.1, standard deviation (SD) 38.2 vs 72.8, SD 93.0 hr; p < 0.001) in the rapid phenotypic AST group. The mean time from blood collection to the AST result was significantly shorter in the rapid phenotypic AST group (48.3, SD 17.6 vs 83.1, SD 22.2 hr).

DISCUSSION

ASP based on rapid phenotypic AST can rapidly optimize antibiotic treatment for bacteraemia in patients with haematological malignancy. Rapid phenotypic AST can improve antimicrobial stewardship in immunocompromised patients.

An innovative magnetic state generator using machine learning techniques

We propose a new efficient algorithm to simulate magnetic structures numerically. It contains a generative model using a complex-valued neural network to generate k-space information. The output information is hermitized and transformed into real-space spin configurations through an inverse fast Fourier transform. The Adam version of stochastic gradient descent is used to minimize the magnetic energy, which is the cost of our algorithm. The algorithm provides the proper ground spin configurations with outstanding performance. In model cases, the algorithm was successfully applied to solve the spin configurations of magnetic chiral structures. The results also showed that a magnetic long-range order could be obtained regardless of the total simulation system size.

FCC to BCC transformation-induced plasticity based on thermodynamic phase stability in novel V10Cr10Fe45CoxNi35-x medium-entropy alloys

We introduce a novel transformation-induced plasticity mechanism, i.e., a martensitic transformation from fcc phase to bcc phase, in medium-entropy alloys (MEAs). A VCrFeCoNi MEA system is designed by thermodynamic calculations in consideration of phase stability between bcc and fcc phases. The resultantly formed bcc martensite favorably contributes to the transformation-induced plasticity, thereby leading to a significant enhancement in both strength and ductility as well as strain hardening. We reveal the microstructural evolutions according to the Co-Ni balance and their contributions to a mechanical response. The Co-Ni balance plays a leading role in phase stability and consequently tunes the cryogenic-temperature strength-ductility balance. The main difference from recently-reported metastable high-entropy dual-phase alloys is the formation of bcc martensite as a daughter phase, which shows significant effects on strain hardening. The hcp phase in the present MEA mostly acts as a nucleation site for the bcc martensite. Our findings demonstrate that the fcc to bcc transformation can be an attractive route to a new MEA design strategy for improving cryogenic strength-ductility.

Active surveillance for carbapenem-resistant Enterobacteriaceae, vancomycin-resistant enterococci and toxigenic Clostridium difficile among patients transferred from long-term care facilities in Korea

A 10-month active surveillance study was conducted to assess carriage of carbapenemase-producing Enterobacteriaceae (CPE), vancomycin-resistant enterococci (VRE) and toxigenic Clostridium difficile colonization among patients transferred to hospital from long-term care facilities (LTCFs). Four (1.4%) patients with carbapenem-resistant Enterobacteriaceae (none of which were CPE), 59 (21%) patients with VRE and 20 (7.1%) patients colonized with toxigenic C. difficile were identified from 282 rectal specimens. There was no outbreak of VRE infection during the study period. The low prevalence of CPE carriage suggests that screening all admissions from LTCFs for CPE would not be cost-effective, and that screening and use of contact precautions for VRE should be reconsidered.

The spin structures of interlayer coupled magnetic films with opposite chirality

Using Monte-Carlo simulations and micromagnetic simulations, we reveal how the spin structural correlation and the skyrmion dynamics are affected by the interlayer coupling in a chiral magnetic bilayer system, in which the two layers have opposite chirality. The interaction through interlayer coupling between chiral magnetic structures influences the static and dynamics properties profoundly. The competition between the Dzyaloshinskii-Moriya interaction and the interlayer interaction allows multiple magnetic structures to be energetically stable, which includes sole skyrmion states (skyrmion appears in only one of the layers) and skyrmion pair states (coupled skyrmions in top and bottom layers). When current driven spin transfer torques are applied to each state, the sole skyrmion state is mainly propelled by a spin transfer torque causing the skyrmion hall effect, but the skyrmion pair state is propelled by a torque from skyrmion-skyrmion interaction and not influenced by the skyrmion hall effect. Also upon application of an external magnetic field, we found the skyrmions in a skyrmion pair state extinguish in an exclusive way, as the annihilation of a skyrmion in one of the layers stabilizes the once paired skyrmion in the other layer, i.e. the skyrmion lattice sites have only one skyrmion in either layer.

Concordance of results of blood and tissue cultures from patients with pyogenic spondylitis: a retrospective cohort study

OBJECTIVES

To investigate the concordance of results of blood and tissue cultures in patients with pyogenic spondylitis.

METHODS

We searched for patients with pyogenic spondylitis in whom microorganisms were isolated from both blood and tissue cultures by retrospective review of medical records in three tertiary university-affiliated hospitals between January 2005 and December 2015. The species and antimicrobial susceptibility patterns of isolates from blood and tissue cultures were compared.

RESULTS

Among 141 patients with pyogenic spondylitis in whom microorganisms were isolated from both blood and tissue cultures, the species of blood and tissue isolates were identical in 135 patients (95.7%, 135/141). Excluding the four anaerobic isolates, we investigated antimicrobial susceptibility patterns of 131 isolates of the same species from blood and tissue cultures. Antibiotic susceptibility patterns were identical in 128 patients (97.7%, 128/131). The most common isolates were Staphylococcus aureus (86 patients; 85 concordant and one discordant), followed by streptococcus (24 patients; 22 concordant and two discordant), and Escherichia coli (eight patients; all concordant).

CONCLUSIONS

We suggest that a positive blood culture from patients with pyogenic spondylitis could preclude the need for additional tissue cultures, especially when S. aureus and streptococcus grew in blood cultures.

Characteristics of cefazolin inoculum effect-positive methicillin-susceptible staphylococcus aureus infection in a multicentre bacteraemia cohort

Cefazolin treatment failure has been observed in high-inoculum infections caused by methicillin-susceptible Staphylococcus aureus (MSSA) with a cefazolin inoculum effect (CIE). However, data on the characteristics and risk factors for the acquisition of CIE-positive MSSA infection are scarce. CIE positivity was measured as an MIC ≥ 16 μg/ml with a high inoculum (∼5 × 10⁷ CFU/ml). The blaZ gene type was assessed through sequence analysis. The clinical characteristics and risk factors for the acquisition of CIE-positive MSSA infection were assessed. The association between the antimicrobial susceptibility profile and CIE positivity was evaluated. A total of 303 MSSA bacteraemia cases and their corresponding isolates were collected from ten hospitals: 61 (20.1 %) isolates showed a positive CIE; 254 (83.8 %) were positive for the blaZ gene. No significant association was found between CIE positivity and the site of infection. Metastatic cancer (aOR 2.86, 95 % CI, 1.10-7.48) and recent (≤1 month) close contact with a chronically ill patient (aOR 4.69, 95 % CI, 1.76-12.50) were identified as significant risk factors for CIE-positive MSSA infection through multivariate analyses. Resistances to clindamycin (OR 3.55, 95 % CI, 1.62-7.80) and erythromycin (OR 5.00, 95 % CI, 2.50-9.99) were associated with CIE positivity, presenting high specificity (92.9 %) and a negative predictive value (82.3 %). CIE-positive MSSA constituted approximately one-fifth of MSSA bacteraemia cases. Although CIE positivity was not clinically discernible, CIE positivity was associated with clindamycin or erythromycin susceptibility. Therefore, our findings suggest that cefazolin can be used in the treatment of high-inoculum MSSA infection if the isolates are susceptible to clindamycin or erythromycin.

Supplementation of Dried Mealworm (Tenebrio molitor larva) on Growth Performance, Nutrient Digestibility and Blood Profiles in Weaning Pigs

This experiment was conducted to investigate the effects of dried mealworm (Tenebrio molitor larva) on growth performance, nutrient digestibility and blood profiles in weaning pigs. A total of 120 weaning pigs (28±3 days and 8.04±0.08 kg of body weight) were allotted to one of five treatments, based on sex and body weight, in 6 replicates with 4 pigs per pen by a randomized complete block design. Supplementation level of dried mealworm was 0%, 1.5%, 3.0%, 4.5%, or 6.0% in experimental diet as treatment. Two phase feeding programs (phase I from 0 day to 14 day, phase II from 14 day to 35 day) were used in this experiment. All animals were allowed to access diet and water ad libitum. During phase I, increasing level of dried mealworm in diet linearly improved the body weight (p<0.01), average daily gain (ADG) (p<0.01) and average daily feed intake (ADFI) (p<0.01). During phase II, ADG also tended to increase linearly when pigs were fed higher level of dried mealworm (p = 0.08). In addition, increasing level of dried mealworm improved the ADG (p<0.01), ADFI (p<0.05) and tended to increase gain to feed ratio (p = 0.07) during the whole experimental period. As dried mealworm level was increased, nitrogen retention and digestibility of dry matter as well as crude protein were linearly increased (p = 0.05). In the results of blood profiles, decrease of blood urea nitrogen (linear, p = 0.05) and increase of insulin-like growth factor (linear, p = 0.03) were observed as dried mealworm was increased in diet during phase II. However, there were no significant differences in immunoglobulin A (IgA) and IgG concentration by addition of dried mealworm in the growth trial. Consequently, supplementation of dried mealworm up to 6% in weaning pigs’ diet improves growth performance and nutrient digestibility without any detrimental effect on immune responses.

Which tissues are best for microbiological diagnosis in patients with pyogenic vertebral osteomyelitis undergoing needle biopsy?

Identification of the causative microorganism is important in the management of pyogenic vertebral osteomyelitis (PVO). The aim of this study was to investigate whether culture positive rates differ between needle biopsy sites in patients with PVO, and which tissues are best for microbiological diagnosis. Between January 2005 and December 2013, we conducted a retrospective cohort study of PVO patients who had soft-tissue abscesses (paraspinal or psoas abscesses) and who received needle biopsy for microbiological diagnosis. Needle biopsy sites were classified into two anatomical categories: vertebral bodies, or soft tissues (intervertebral discs, paraspinal abscesses, or psoas abscesses). A generalized estimating equation model was developed to identify factors associated with tissue-culture positivity. During the study period a total of 136 tissues were obtained by needle biopsy from 128 PVO patients with soft-tissue abscesses. The culture positive rates of vertebral bodies and soft tissues were 39.7% (29/73), and 63.5% (40/63), respectively (p < 0.05). In a multivariate analysis, male gender (adjusted odds ratio (aOR) 2.24, 95% CI 1.00-5.02), higher C-reactive protein (aOR 1.07, 95% CI 1.01-1.15), positive blood culture (aOR 2.57, 95% CI 1.01-6.59), and soft tissues as biopsy site compared with vertebral bodies (aOR 2.28, 95% CI 1.08-4.78) were independent factors associated with tissue culture positivity. Soft tissues were the best sites for microbiological diagnosis in PVO patients undergoing needle biopsy.

The role of retrobulbar and retinal circulation on optic nerve head and retinal nerve fibre layer structure in patients with open-angle glaucoma over an 18-month period

BACKGROUND/AIMS

Evidence suggests that vascular abnormalities play a role in the pathogenesis of open-angle glaucoma (OAG) in some patients. This study aims to assess changes in retrobulbar and retinal blood flow over time in patients with glaucoma and examine their relationship to glaucomatous progression, as determined by retinal and optic nerve structure.

METHODS

In this observational study, 103 patients with OAG were examined at baseline and 18 months follow-up. Retrobulbar blood flow was measured by colour Doppler imaging in the ophthalmic, central retinal and temporal posterior ciliary artery (TPCA) and nasal short posterior ciliary artery. Retinal capillary blood flow was measured by confocal scanning laser Doppler. Peripapillary retinal nerve fibre layer thickness was assessed by optical coherence tomography. Non-parametric Wilcoxon signed ranks tests were used to assess for any statistically significant changes between the baseline and 18-month visits for the retrobulbar and retinal flow, as well as the structural parameters.

RESULTS

In general, retinal and retrobulbar blood flow parameters decreased over 18 months. Thinning of the optic disc rim and increase in cup area were associated with a higher resistance index (p=0.0334) and lower peak systolic velocity of TPCA (p=0.0282), respectively. A higher amount of retinal zero pixel blood flow correlated with a greater increase in cup/disc ratio (p=0.0170).

CONCLUSIONS

Reductions in retrobulbar and retinal blood flow over time were associated with structural glaucomatous progression, as indicated by retinal and optic nerve changes.

Novel therapies for open-angle glaucoma

Open-angle glaucoma is a multifactorial optic neuropathy characterized by progressive loss of retinal ganglion cells and their axons. It is an irreversible disease with no established cure. The only currently approved treatment is aimed at lowering intraocular pressure, the most significant risk factor known to date. However, it is now clear that there are other risk factors involved in glaucoma's pathophysiology. To achieve future improvements in glaucoma management, new approaches to therapies and novel targets must be developed. Such therapies may include new tissue targets for lowering intraocular pressure, molecules influencing ocular hemodynamics, and treatments providing neuroprotection of retinal ganglion cells. Furthermore, novel drug delivery systems are in development that may improve patient compliance, increase bioavailability, and decrease adverse side effects.

Mathematical modeling approaches in the study of glaucoma disparities among people of African and European descents

Open angle glaucoma (OAG) is a severe ocular disease characterized by progressive and irreversible vision loss. While elevated intraocular pressure (IOP) is a well-established risk factor for OAG, the progression of OAG in many cases, despite IOP treatment, suggests that other risk factors must play significant roles in the development of the disease. For example, various structural properties of the eye, ocular blood flow properties, and systemic conditions have been identified as risk factors for OAG. Ethnicity has also been indicated as a relevant factor that affects the incidence and prevalence of OAG; in fact, OAG is the leading cause of blindness among people of African descent. Numerous clinical studies have been designed to examine the possible correlation and causation between OAG and these factors; however, these studies are met with the challenge of isolating the individual role of multiple interconnected factors. Over the last decade, various mathematical modeling approaches have been implemented in combination with clinical studies in order to provide a mechanical and hemodynamical description of the eye in relation to the entire human body and to assess the contribution of single risk factors to the development of OAG. This review provides a summary of the clinical evidence of ocular structural differences, ocular vascular differences and systemic vascular differences among people of African and European descent, describes the mathematical approaches that have been proposed to study ocular mechanics and hemodynamics while discussing how they could be used to investigate the relevance to OAG of racial disparities, and outlines possible new directions of research.

TM-25659 enhances osteogenic differentiation and suppresses adipogenic differentiation by modulating the transcriptional co-activator TAZ

BACKGROUND AND PURPOSE

The transcriptional co-activator with PDZ-binding motif (TAZ) is characterized as a transcriptional modulator of mesenchymal stem cell differentiation into osteoblasts and adipocytes. Moreover, increased TAZ activity in the nucleus enhances osteoblast differentiation and suppresses adipocyte development by interacting with runt-related transcription factor 2 (RUNX2) and PPARγ, respectively. Therefore, it would be of interest to identify low MW compounds that modulate nuclear TAZ activity.

EXPERIMENTAL APPROACH

High-throughput screening was performed using a library of low MW compounds in order to identify TAZ modulators that enhance nuclear TAZ localization. The effects and molecular mechanisms of a TAZ modulator have been characterized in osteoblast and adipocyte differentiation.

KEY RESULTS

We identified 2-butyl-5-methyl-6-(pyridine-3-yl)-3-[2'-(1H-tetrazole-5-yl)-biphenyl-4-ylmethyl]-3H-imidazo[4,5-b]pyridine] (TM-25659) as a TAZ modulator. TM-25659 enhanced nuclear TAZ localization in a dose-dependent manner and attenuated PPARγ-mediated adipocyte differentiation by facilitating PPARγ suppression activity of TAZ. In addition, TAZ-induced RUNX2 activity activation was further increased in osteoblasts, causing increased osteoblast differentiation. Accordingly, TM-25659 suppressed bone loss in vivo and decreased weight gain in an obesity model. After oral administration, TM-25659 had a favourable pharmacokinetic profile.

CONCLUSION AND IMPLICATIONS

TM-25659 stimulated nuclear TAZ localization and thus caused TAZ to suppress PPARγ-dependent adipogenesis and enhance RUNX2-induced osteoblast differentiation in vitro and in vivo. Our data suggest that TM-25659 could be beneficial in the control of obesity and bone loss.

Gain recovery in a quantum dot semiconductor optical amplifier and corresponding pattern effects in amplified optical signals at 1.5 μm

Fast gain recovery observed in quantum-dot semiconductor-optical-amplifiers (QDSOAs) is useful for amplifying high-speed optical signals. The small but finite slow recovery component can deteriorate the signal amplification due to the accumulation of gain saturation during 10 Gb/s operation. A study of the gain recoveries and pattern effects in signals amplified using a 1.5 μm InAs/InGaAsP QDSOA reveals that the gain recovery is always fast, and pattern-effect-free amplification is observed at the ground state. However, at the excited state, the slow component increases with the current, and significant pattern effects are observed. Simulations of the pattern effects agreed with the observed experimental trends.

Multiplexed nanoflares: mRNA detection in live cells

We report the development of the multiplexed nanoflare, a nanoparticle agent that is capable of simultaneously detecting two distinct mRNA targets inside a living cell. These probes are spherical nucleic acid (SNA) gold nanoparticle (Au NP) conjugates consisting of densely packed and highly oriented oligonucleotide sequences, many of which are hybridized to a reporter with a distinct fluorophore label and each complementary to its corresponding mRNA target. When multiplexed nanoflares are exposed to their targets, they provide a sequence specific signal in both extra- and intracellular environments. Importantly, one of the targets can be used as an internal control, improving detection by accounting for cell-to-cell variations in nanoparticle uptake and background. Compared to single-component nanoflares, these structures allow one to determine more precisely relative mRNA levels in individual cells, improving cell sorting and quantification.

Strong tunable slow and fast lights using a gain-clamped semiconductor optical amplifier

Previously demonstrated slow light is still far from applications, particularly due to the limited bandwidth and control speed. Although semiconductor-based slow light has the high bandwidth and sub-nanosecond control speed, slow light was observed only in the absorption regime with attenuation, while fast light observed in the gain regime with amplification. The large power difference in two regimes makes the use of the optical delay impractical. We report novel slow light in the gain regime, with a high power comparable to that of fast light, utilizing the anomalous gain characteristic in a gain-clamped semiconductor optical amplifier. The slow light is tunable to fast light with the current as the only variable. Additional high speed operation, fast delay control, and wide range of operation wavelength make the present approach practical.

Retrobulbar optic neuritis and meningoencephalitis following progressive outer retinal necrosis due to CMV in a patient with AIDS

We report on a 34-year-old male patient with AIDS who developed retrobulbar optic neuritis and meningoencephalitis following bilateral progressive outer retinal necrosis (PORN) caused by cytomegalovirus (CMV). This case documents the presumed association of PORN with retrobulbar optic neuritis, and CMV meningoencephalitis in an AIDS patient.

Prevalence, microbiology, and clinical characteristics of extended-spectrum beta-lactamase-producing Enterobacter spp., Serratia marcescens, Citrobacter freundii, and Morganella morganii in Korea

We examined the prevalence and characteristics of extended-spectrum beta-lactamase (ESBL)-producing clinical isolates among Enterobacter spp., Serratia marcescens, Citrobacter freundii, and Morganella morganii, and evaluated screening criteria, clinical characteristics and outcomes of infections caused by ESBL-producing organisms. Between January and June 2005, a total of 493 nonduplicate consecutive isolates were collected at Asan Medical Center, a 2,300-bed tertiary hospital in Seoul, Republic of Korea. Fifty isolates (10.1%) were positive for phenotypical ESBL-test. The positive rate of phenotypical ESBL-test in Enterobacter spp., S. marcescens, C. freundii, and M. morganii was 12.8%, 12.4%, 4.9%, and 0% respectively. SHV-12 (18 isolates), CTX-M-9 (17 isolates), and TEM-52 (five isolates) were the most prevalent ESBL types. The ESBL in 17 strains could not be identified. As an ESBL screening criterion, the cefepime MIC >or=1 microg/ml had the highest sensitivity (0.84) and specificity (0.87). Half of the ESBL-producing isolates (25/50) were judged as pathogens. Cholangitis (ten cases), and pneumonia (six cases) were the most common infections. The overall mortality was 12.0%.

Electrically tunable slow and fast lights in a quantum-dot semiconductor optical amplifier near 1.55 microm

We have demonstrated both slow light in the absorption regime and fast light in the gain regime of a 1.55 microm quantum-dot semiconductor optical amplifier at room temperature. The theory with coherent population oscillations and four-wave mixing effects agrees well with the experimental results. We have observed a larger phase delay at the excited state than that at the ground state transition, likely due to the higher gain and smaller saturation power of the excited state.

One-year adherence to clinic visits after highly active antiretroviral therapy: a predictor of clinical progress in HIV patients

OBJECTIVE

To determine whether adherence to clinic visits early after initiation of highly active antiretroviral therapy (HAART) is predictive of long-term clinical outcome.

DESIGN

Observational cohort study.

SETTING

A tertiary referral hospital.

SUBJECTS

A total of 387 adult HIV patients who were followed for at least 1 year after initiation of HAART between January 1998 and December 2004.

MAIN OUTCOME MEASUREMENTS

The effect of 1-year adherence to clinic visits on the occurrence of new AIDS-defining illness or death was assessed using Kaplan-Meier survival estimates, and hazard ratios were estimated using Cox proportional hazards regression model.

RESULTS

Multivariate analysis revealed that advanced clinical stage, fewer new drugs in HAART, and longer total elapsed time without clinical visits for 1 year after HAART were all significant risk factors for the occurrence of new AIDS-defining illnesses or death. Compared with no missed visits, the hazard ratio adjusted by clinical stage and number of new drugs in HAART was 2.87 (95% confidence interval [CI], 1.34-6.16, P = 0.007) for one missed appointment, 4.37 (95% CI: 1.74-10.98, P = 0.002) for two, and 8.19 (95% CI: 2.95-22.78, P < 0.001) for three or more.

CONCLUSION

Adherence to clinic visits early after initiation of HAART is an independent predictor for long-term clinical progression in HIV patients.

Pulmonary tuberculosis in young Korean soldiers: incidence, drug resistance and treatment outcomes

OBJECTIVE

To determine the incidence and treatment outcomes of pulmonary tuberculosis (PTB) in young soldiers of South Korea.

DESIGN

From 2000 to 2004, all soldiers with a new diagnosis of tuberculosis (TB) were enrolled in the study, based on the official records of the Armed Forces Medical Command. The demographic and clinical data of the cases were evaluated retrospectively.

RESULTS

A total of 3115 TB cases were reported during the study period, of whom 2071 (66.5%) were reported as PTB. The annual incidence rates of PTB were 96.4 per 100,000 population in 2000, 89.3 in 2001, 67.6 in 2002, 60.2 in 2003, and 63.1 in 2004. A total of 270 patients diagnosed and treated at the Armed Forces Capital Hospital were analysed. Of the Mycobacterium tuberculosis isolates, 87.4% were susceptible to all available anti-tuberculosis drugs; 253 (93.7%) patients eventually completed initial anti-tuberculosis treatment. Among the patients with smear-positive PTB, the cure rate was 89.3% (100/112).

CONCLUSION

Our results demonstrate that the incidence of PTB in Korean soldiers, although still high, was declining steadily. With good case management, the overall success rate of initial treatment was approximately 90%.

Pancreas Retransplantation: Outcomes of 20 Cases

The objective of this paper was to evaluate our initial experience with pancreas retransplantation. From January 26, 1996 to February 2005, 285 pancreas transplantations were performed, including 20 (7%) retransplants. The causes of primary graft loss were graft thrombosis in 11 (55%, 7 venous and 4 arterial); 4 (20%) chronic rejections; 2 (10%) ischemia/reperfusion injury; 1 severe graft pancreatitis; 1 primary nonfunction; and 1 sepsis. Venous drainage was placed in the iliac vessels in 14 (70%), vena cava in 5 (25%), and portal drainage in 1. The exocrine drainage was vesical in 16 (80%) and enteric in 4 (20%). In 14 cases (70%), the primary graft was removed before and in 6 (30%) at the time of retransplantation. Immunosuppression was based on antilymphocyte induction, tacrolimus, mycophenolate mofetil, and steroids in all patients. One-year patient and graft survivals were 95% and 85%. In conclusion, pancreas retransplants were feasible with results comparable to a primary pancreas transplantation.

Association between arterial stiffness and the deformability of red blood cells (RBCs)

The relationship between the flexibility of atherosclerotic vessels and RBC deformability has been investigated. A significant difference of RBC deformability was found among the arterial stiffness groups classified by oscillometric measurement of blood pressure. The deformability was determined by direct microscopic observation of RBCs subjected to shear stress of 0.3 to 40.0 Pa with a rotating rheoscope. The deformability of stiffen group - abnormal pulse wave pattern group or moderate cardiovascular risk group - was found to be much higher than that of normal groups in wide shear stress region (3.0, 10.0, 30.0, and 40.0 Pa). We postulate that the body adapts high shear stress in vivo by making RBCs more distensible, and therefore less likely to rupture under strain or microcirculatory alterations.

Is cholecystectomy necessary after ERCP for bile duct stones in patients with gallbladder in situ?

BACKGROUND

The requirement for subsequent cholecystectomy in patients with gallbladder in situ after endoscopic removal of stones from the common bile duct (CBD) is controversial. The aims of this study were to assess the requirement for subsequent cholecystectomy for gallbladder-related symptoms, and to identify the patients who develop symptoms after the endoscopic removal of CBD stones.

METHODS

Of 241 patients with gallbladder in situ following endoscopic removal of stones from the CBD, 146 patients (78 men and 68 women; mean age 69 +/- 13 years, range 20-93) with a follow-up time of more than three months without elective cholecystectomy were enrolled in the study. Fifty-nine patients had gallbladder stones (single stones in 27 and multiple stones in 32) and 87 patients had gallbladder in situ without stones. The time from entry to the occurrences of death or cholecystectomy was evaluated retrospectively. Cox regression analysis was used to evaluate the risk factors associated with these events.

RESULTS

The mean duration of follow-up was 24.1 +/- 18.0 months (range 3-70 months). During follow-up, seven patients (4.8%) underwent cholecystectomy, on average 18.4 months after CBD stone removal, as the result of acute cholecystitis in four cases, biliary pain in two cases and acute pancreatitis in one case. Laparoscopic cholecystectomy was performed in four patients and open cholecystectomy in three patients. Post-operative morbidity occurred in two patients, with improvement after conservative management. Nine patients (6.2%) died as the result of unrelated biliary disease. Age, sex, presence of gallbladder stones, multiplicity of gallbladder stones and underlying disease did not correlate with subsequent cholecystectomy by Cox regression analysis.

CONCLUSION

Elective cholecystectomy is not warranted in patients with bile duct stones when the common duct can be cleared of stones by endoscopic sphincterotomy. We could not find any clinical predictors of further symptoms or complications arising from the retained gallbladder.

Effects of Shikunshito-Kamiho on fecal enzymes and formation of aberrant crypt foci induced by 1,2-dimethylhydrazine

Shikunshito-Kamiho (SKTK) is a traditional Chinese medicine composed of eight crude drugs (Ginseng Radix, Hoelen, Atractylodis Rhizoma, Glycyrrhizae Radix, Prunellae Spica, Ostreae Testa, Laminaria Thallus, Sargassum). We investigated the effects of SKTK on pH, ammonia, fecal enzymes such as beta-glucuronidase, tryptophanase, urease, and formation aberrant crypt foci in the colon carcinogenesis model induced by 1,2-dimethylhydrazine (DMH). Water extract of SKTK was administered orally for 5 weeks to DMH-treated mice as 0.5% and 1.5% of the diet. Beta-glucuronidase, pH and tryptophanase were significantly inhibited after treatment of 0.5% and 1.5% SKTK, while urease was significantly reduced only during and after treatment of 1.5% SKTK as compared with control data. However, the ammonia concentration wasn't different in SKTK treated groups from control group. The incidence number of aberrant crypts foci (ACF) and aberrant crypts/focus in colon was significantly decreased by 0.5% and 1.5% SKTK mixed diets compared with that in rats treated with DMH alone. These results suggest that SKTK exterts anticarcinogenic activity on experimental murine colorectal cancer.

Even-odd alternation in mass spectrum of thymine and uracil clusters: evidence of intracluster photodimerization

Multiphoton ionization of thymine and uracil clusters generated by a supersonic molecular beam gave rise to a remarkable alternation of mass spectral intensities between even- and odd-numbered clusters. Such alternation was observed in clusters of up to 30 molecules. Excitation to the two lowest electronically excited states seemed to be a strong prerequisite. In view of the well known photodimerization reaction of thymine and uracil in the bulk phase, it is proposed that such alternation in the mass spectral intensity resulted from formation of photodimer units within the cluster on intense UV irradiation. Several analogues of thymine with no known propensity for photodimerization in the bulk phase did not exhibit any sign of such alternation in the cluster mass spectrum. The intrinsic UV window for photodimerization, and hence photoinduced mammalian mutagenesis, was estimated to be approximately 210-280 nm, significantly narrower than the previously reported bulk values of 150-300 nm.

The conformation and activity relationship of benzofuran type of angiotensin II receptor antagonists

As a continuing effort to establish the structure and activity relationship in a benzofuran type of angiotensin II antagonist, we synthesized various regioisomers and performed a series of QSAR analyses. The conformational analyses of target isomers were carried out using molecular mechanics and fine-tuned using the information from the NMR NOE experiment. The conformations of compounds with a good binding activity are quite similar to that of DuP753, a prototype of AII antagonist, suggesting that these compounds also bind to the same site of AII receptor. We then studied the compounds with a varied length of the hydroxyl group bearing side chain to find out the optimum distance between the hydroxyl group and the imidazole ring. The CoMFA with these compounds gave acceptable statistical measures (cross-validated r2 and conventional r2 to be 0.881 and 0.974, respectively) and the map was well consistent with the previously proposed pharmacophore.

Inhibitory effects of crude drugs on alpha-glucosidase

The inhibitory activity of several crude drugs on alpha-glucosidases, which are the key enzymes for carbohydrate digestion and the prevention of diabetic complications, was investigated. Several crude drugs including Terminaliae Fructus, Mori Cortex Radicis, Caesalpiniae Lignum and Gyrophora esculenta potently inhibited maltase and sucrase isolated from rat intestine, while Arecae Semen and Corni Fructus remarkably inhibited alpha-amylase. Caesalpiniae Lignum and Gyrophora esculenta exhibited significant reductions of blood glucose elevation in mice loaded with maltose and sucrose.

Comparison of organic and inorganic packing materials in the removal of ammonia gas in biofilters

Two organic and two inorganic packing materials were compared with regard to the removal of ammonia gas in a biofilter inoculated with night-soil sludge. By gradually increasing the inlet load of ammonia, the complete removal capacity, which was defined as the inlet load of ammonia that was completely removed, and the maximum removal capacity of ammonia, which was the value when the removal capacity leveled off for each packing material, were estimated. Both values which were based on a unit volume of packing material, were higher for organic packing materials than inorganic ones. By using kinetic analysis, the maximum removal rate of ammonia, V(m), and the saturation constant, K(s), were determined for all packing materials and the values of V(m) for organic packing materials were found to be larger. By using the kinetic parameters, the removal rates for ammonia were compared among the four packing materials, and the organic packing materials showed superior performance for the removal of ammonia in the concentration range of 0-300 ppm as compared to inorganic packing materials.

Beta-glucuronidase inhibitory activity and hepatoprotective effect of 18 beta-glycyrrhetinic acid from the rhizomes of Glycyrrhiza uralensis

An inhibitor of beta-glucuronidase from the rhizomes of Glycyrrhiza uralensis was isolated and its hepatoprotective activity on CCI4-induced hepatotoxicity of rats was investigated. From the water-soluble extract of G. uralensis, glycyrrhizin was isolated as a potent inhibitor of beta-glucuronidase. When glycyrrhizin was orally administered, it had a hepatoprotective activity. However, when glycyrrhizin was intraperitoneally administered, it did not have a hepatoprotective activity. 18 beta-Glycyrrhetinic acid, which is a major metabolite of glycyrrhizin by human intestinal bacteria, was also a potent inhibitor of beta-glucuronidase. When 18 beta-glycyrrhetinic acid was intraperitoneally administered, it also had some hepatoprotective activity. These results suggest that glycyrrhizin may be a natural prodrug for the observed hepatoprotective effect in rats and that serum beta-glucuronidase levels have implications for the liver injury, as reductions of its activity by administration of inhibitors such as G. uralensis or its derived products and silymarin correlate with reductions in biochemical indices of liver injury.

Removal of a high load of ammonia gas by a marine bacterium, Vibrio alginolyticus

A newly isolated marine bacterium, Vibrio alginolyticus was used to remove a high load of ammonia gas. By a stepwise increase in ammonia supply over the concentration range of 120-2000 ppm (v/v), complete removal of ammonia was observed from the start of the experiment in a suspended culture of the bacterium in basal medium containing 3% NaCl. When cells were inoculated onto an inorganic packing material in a biofilter, and a high load of ammonia was introduced continuously under nonsterile conditions, the average percentage of gas removed exceeded 85% for a 61-d operation. The maximum removal capacity and the complete removal capacity were 22.8 g-N/kg-dry packing material/d and 18.6 g-N/kg-dry packing material/d, respectively, which were about four times larger than those obtained in nitrifying sludge inoculated onto the same packing material. During this operation, the nonsterile air supply had no adverse effect on the removability of ammonia by V. alginolyticus.

Spectrum of opportunistic infections and malignancies in patients with human immunodeficiency virus infection in South Korea

To determine the frequency and types of major opportunistic diseases in patients with HIV infection in South Korea, we reviewed the medical records of 173 HIV-infected patients. The patients were seen from 1985 to 1998 at a referral hospital for AIDS in South Korea. Most patients (85%) were male, and 107 (62%) were infected by heterosexual contacts. CD4+ lymphocyte counts at presentation were <200/microL in 27% of the patients. Tuberculosis was the most frequent opportunistic infection (25% of patients), followed by candidiasis (21%), herpes zoster (20%), Pneumocystis carinii pneumonia (10%), cytomegalovirus disease (9.8%). There were no cases of toxoplasmosis. Kaposi's sarcoma developed in 3 patients (1.7%), and non-Hodgkin's lymphoma, in 2 (1.2%). Eleven patients (6.4%) developed peripheral neuropathy, and 8 (4.6%) had HIV encephalopathy. Tuberculosis was the single most important HIV-related infection in South Korean patients.

Beta-glucuronidase-inhibitory activity and hepatoprotective effect of Ganoderma lucidum

To prove the relationship between the fluctuation in serum beta-glucuronidase level and hepatotoxicity, an inhibitor of beta-glucuronidase from G. lucidum was isolated and its hepatoprotective activity was investigated. The ether fraction of G. lucidum, which had potent beta-glucuronidase-inhibitory activity, protected against CCl4-induced liver injury. From this ether fraction, ganoderenic acid A, was isolated as the potent inhibitor of beta-glucuronidase. It had a potent hepatoprotective effect against CCl4-induced liver injury. These results suggest that the beta-glucuronidase seems to be closely related to liver injury, which could be prevented by beta-glucuronidase inhibitors.

T cell subsets in chronic hepatitis B and the effect of prednisolone withdrawal and interferon alpha-2b

OBJECTIVES

The evaluations of the pathogenetic roles of cell mediated immunity and of the preventive effect for disease progression with interferon(IFN) treatment in patients with chronic active hepatitis-B(CAH-B) are the objectives of this study.

METHODS

Thirty-two patients with CAH-B were treated with interferon alpha-2b(IFN alpha-2b) with prednisolone withdrawal and 30 control patients were treated with conventional hepatotonics for 6 months. Peripheral total T cell fractions and T cell subsets of the patients with CAH-B, treated with IFN alpha-2b with prednisolone withdrawal, were examined 1 month before administration of prednisolone, and compared with 12 normal controls for assessing the potential role of cellular immunity in the development of CAH-B. To estimate the effectiveness of IFN therapy for the patients with CAH-B, levels of various liver function tests, HBsAg, anti-HBs, HBeAg, anti-HBe, HBV DNA, anti-HCV and others were assessed for the treatment group and compared with control patients at pre- and post-treatment period each.

RESULTS

The value of CD4 was significantly lower in patients with CAH-B than normal controls (36.3 +/- 7.7% vs 42.1 +/- 5.7%, p < 0.05) and the value of CD8 was significantly higher in patients with CAH-B than normal controls (30.6 +/- 10.3% vs 24.3 +/- 5.2%, p < 0.05) before prednisolone administration. The patients in responder group (n = 26) had significantly lower CD4 cells compared with normal controls, but non-responders (n = 6) did not have. The levels of liver function test(LFT) in the patients with IFN alpha-2b treatment with prednisolone withdrawal were not different from the control patient group at pretreatment, but significantly lower than control patient group's after treatment, regardless of response to IFN alpha-2b treatment with prednisolone withdrawal.

CONCLUSIONS

The cellular immunity of the host may have a potential role in the pathogenesis of chronicity of hepatitis B infection. IFN alpha-2b treatment with prednisolone withdrawal may be regarded as one of the effective treatment modalities for the inhibition of disease progression in patients with CAH-B.

Anti-Helicobacter pylori activity of herbal medicines

The extracts of Coptidis japonica (rhizoma), Eugenia caryophyllata (flower), Rheum palmatum (rhizoma), Magnolia officinalis (cortex) and Rhusjavanica (galla rhois) potently inhibited the growth of Helicobacter pylori (HP). However, these herbal extracts showed no inhibitory effect on HP urease except Galla rhois. Among the components separated from active herbal extracts by silica gel column chromatography, the inhibitory effects of decursinol angelate and decursin on the growth of HP were the most potent, followed by magnolol, berberine, cinnamic acid, decursinol and gallic acid. Minimum inhibitory concentrations (MICs) of decursin and decursinol angelate were 6-20 microg/ml.

A case of Marfan syndrome with acute monoblastic leukemia

We report on an 18-year-old man who had both acute monoblastic leukemia and Marfan syndrome. A diagnosis of Marfan syndrome was established by those characteristics of arachnodactyly, ectopia lentis, mitral valve prolapse, and mitral regurgitation. Findings on bone marrow examination of the patient showed that most of nucleated cells were monoblasts and immunophenotype of those cells showed CD13+, CD33+, CD56+, and HLA-DR+. To our knowledge, this is the second report of leukemia in Marfan syndrome in the world.

Application of capillary electrophoresis to amino acid sequencing of peptide

Separations of twenty phenylthiohydantoin (PTH) amino acids, and amino acid derivatives, resulting from the Edman degradation of peptides and proteins, were optimized for peptide sequencing by capillary electrophoresis. Manual sequencing of angiotensin II was performed by Edman degradation and capillary electrophoresis of the PTH amino acid obtained after each cycle. The results were compared with those of an automated conventional protein sequencer. Interfacing capillary electrophoresis with Edman degradation provides an additional option for protein sequencing.

The conformation and activity relationship of fused analogs of DuP753

We have prepared three conformationally restricted analogs of DuP753 in which one of the phenyl rings in the biphenyl moiety is fused to the imidazole ring, and have investigated the conformation-biological activity relationship of these compounds. Conformational analysis on DuP753 and these compounds confirms that a specific 3-dimensional arrangement of pharmacophoric elements is essential for biological activity.

Analysis of antiepileptic drugs in human plasma using micellar electrokinetic capillary chromatography

We describe a method for the simultaneous determination of antiepileptic drugs (ethosuccimide, phenytoin, primidone, phenobarbital, carbamazepine and valproic acid) by micellar electrokinetic capillary chromatography using sodium dodecyl sulphate as the micellar phase. Factors affecting the micellar electrokinetic separation were studied for the quantitative determination of these drugs in human plasma. The confirmation of the peaks and the specificity of the method were investigated by combining multiwavelength detection with micellar electrokinetic capillary chromatography.

Separation of theophylline and its analogues by micellar electrokinetic chromatography: application to the determination of theophylline in human plasma

Micellar electrokinetic chromatographic separation of theophylline and its analogues was investigated using sodium dodecyl sulphate (SDS) as a micellar phase. The effects of pH, micelle concentration, applied voltage and temperature on the separation and preliminary quantitative analysis were studied for the determination of theophylline in human plasma. The data indicate that this technique could be used as the reference or routine method of theophylline measurement in therapeutic drug monitoring.

Etiologic considerations of nonspecific pleuritis

Twenty-three patients with nonspecific pleuritis were studied to determine clinical outcome. After a mean follow-up period of 6 months (1 to 36 months), a diagnosis was reached in 17 patients, while 6 patients remained unknown. The causes of the nonspecific pleuritis diagnosed on initial pleural biopsy were tuberculosis (11 patients, 48%), neoplasm (2 patients, 8.7%), parapneumonic effusion (1 patient), subphrenic abscess (1 patient), congestive heart failure (1 patients), and nephrotic syndrome (1 patient). The diagnosis was made by therapeutic trials (tuberculosis: 11 patients, parapneumonic effusion: 1 patient, congestive heart failure: 1 patient), by repeat pleural biopsy in 1 hepatoma, by open thoractomy in 1 lung cancer, by exploratory laparotomy in 1 subphrenic abscess, and by kidney biopsy in 1 nephrotic syndrome. The WBC counts (more than 2,000/mm3) and lymphocyte percentage (more than 60%) in the pleural fluid were significantly elevated in the patients with tuberculosis compared to those with malignant pleurisy, and other laboratory data were meaningless. As a result of this investigation, we suggest that tuberculous pleurisy is the most common cause of nonspecific pleuritis in Korea and that therapeutic trial with antituberculous medication for patients with high WBC count and lymphocyte percent in pleural fluid can help to locate the nonspecific pleuritis.