Early experience with pure laparoscopic donor hepatectomy: comparison with open donor hepatectomy and non-donor laparoscopic hepatectomy

BACKGROUND

Pure laparoscopic donor hepatectomy (L-DH) has seen a rise in uptake in recent years following the popularization of minimally invasive modality for major hepatobiliary surgery. Our study aimed to determine the safety and compare the perioperative outcomes of L-DH with open donor hepatectomy (O-DH) and laparoscopic non donor hepatectomy (L-NDH) based on our single institution experience.

METHODS

Eighty of 113 laparoscopic hemi-hepatectomies performed between 2015 and 2022 met study inclusion criteria. Of these, 11 were L-DH. PSM in a 1:2 ratio of L-DH versus L-NDH and 1:1 ratio of L-DH versus O-DH were performed, identifying patients with similar baseline clinicopathological characteristics.

RESULTS

After 2:1 matching, the L-DH cohort were significantly younger (P < 0.001) and had lower ASA scores (P < 0.001) than the L-NDH cohort. L-DH was associated with a longer median operating time (P < 0.001) and shorter median postoperative stay (P < 0.001) than L-NDH. After 1:1 matching, there were no significant differences in baseline demographic between the L-DH and O-DH cohorts. L-DH was associated with lower median blood loss (P = 0.040) and shorter length of stay compared to O-DH (P = 0.004). There were no significant differences in recipient outcomes for both cohorts.

CONCLUSION

L-DH can be adopted safely by surgeons experienced in L-NDH and ODH. It is associated with decreased blood loss and shorter length of stay compared to O-DH.

Pre-operative erector spinae plane block should be considered a viable option for laparoscopic colectomies

BACKGROUND

The Erector Spinae Plane (ESP) block is a recent development in the field of regional anaesthesia and has been increasingly explored for abdominal surgeries to reduce opioid use and improve pain control. Colorectal cancer is the commonest cancer in multi-ethnic Singapore and requires surgery for curative treatment. ESP is a promising alternative in colorectal surgeries, but few studies have evaluated its efficacy in such surgeries. Therefore, this study aims to evaluate the use of ESP blocks in laparoscopic colorectal surgeries to establish its safety and efficacy in this field.

METHODS

A prospective two-armed interventional cohort study comparing T8-T10 ESP blocks with conventional multimodal intravenous analgesia for laparoscopic colectomies was conducted in a single institution in Singapore. The decision for doing an ESP block versus conventional multimodal intravenous analgesia was made by a consensus between the attending surgeon and anesthesiologist. Outcomes measured were total intra-operative opioid consumption, post-operative pain control and patient outcome. Post-operative pain control was measured by pain score, analgesia use, and amount of opioids consumed. Patient outcome was determined by presence of ileus.

RESULTS

A total of 146 patients were included, of which 30 patients received an ESP block. Overall, the ESP group had a significantly lower median opioid usage both intra-operatively and post-operatively (p = 0.031). Fewer patients required patient-controlled analgesia and rescue analgesia post-operatively for pain control (p < 0.001) amongst the ESP group. Pain scores were similar and post-operative ileus was absent in both groups. Multivariate analysis found that the ESP block had an independent effect on reducing intra-opioid consumption (p = 0.014). Multivariate analysis of post-operative opioid use and pain scores did not yield statistically significant results.

CONCLUSIONS

The ESP block was an effective alternative regional anaesthesia for colorectal surgery that reduced intra-operative and post-operative opioid use while attaining satisfactory pain control.

An international multicentre propensity score matched analysis comparing between robotic versus laparoscopic left lateral sectionectomy

BACKGROUND

Left lateral sectionectomy (LLS) is one of the most commonly performed minimally invasive liver resections. While laparoscopic (L)-LLS is a well-established technique, over traditional open resection, it remains controversial if robotic (R)-LLS provides any advantages of L-LLS.

METHODS

A post hoc analysis of 997 patients from 21 international centres undergoing L-LLS or R-LLS from 2006 to 2020 was conducted. A total of 886 cases (214 R-LLS, 672 L-LLS) met study criteria. 1:1 and 1:2 propensity score matched (PSM) comparison was performed between R-LLS & L-LLS. Further subset analysis by Iwate difficulty was also performed. Outcomes measured include operating time, blood loss, open conversion, readmission rates, morbidity and mortality.

RESULTS

Comparison between R-LLS and L-LLS after PSM 1:2 demonstrated statistically significantly lower open conversion rate in R-LLS than L-LLS (0.6% versus 5%, p = 0.009) and median blood loss was also statistically significantly lower in R-LLS at 50 (80) versus 100 (170) in L-LLS (p = 0.011) after PSM 1:1 although there was no difference in the blood transfusion rate. Pringle manoeuvre was also found to be used more frequently in R-LLS, with 53(24.8%) cases versus to 84(12.5%) L-LLS cases (p < 0.001). There was no significant difference in the other key perioperative outcomes such as operating time, length of stay, postoperative morbidity, major morbidity and 90-day mortality between both groups.

CONCLUSION

R-LLS was associated with similar key perioperative outcomes compared to L-LLS. It was also associated with significantly lower blood loss and open conversion rates compared to L-LLS.

Robotic Versus Laparoscopic Left and Extended Left Hepatectomy: An International Multicenter Study Propensity Score-Matched Analysis

BACKGROUND

Controversies exist among liver surgeons regarding clinical outcomes of the laparoscopic versus the robotic approach for major complex hepatectomies. The authors therefore designed a study to examine and compare the perioperative outcomes of laparoscopic left hepatectomy or extended left hepatectomy (L-LH/L-ELH) versus robotic left hepatectomy or extended left hepatectomy (R-LH/R-ELH) using a large international multicenter collaborative database.

METHODS

An international multicenter retrospective analysis of 580 patients undergoing L-LH/L-ELH or R-LH/R-ELH at 25 specialized hepatobiliary centers worldwide was undertaken. Propensity score-matching (PSM) was used at a 1:1 nearest-neighbor ratio according to 15 perioperative variables, including demographics, tumor characteristics, Child-Pugh score, presence of portal hypertension, multiple resections, histologic diagnosis, and Iwate difficulty grade.

RESULTS

Before the PSM, 190 (32 %) patients underwent R-LH/R-ELH, and 390 (68 %) patients underwent L-LH/L-ELH. After the matching, 164 patients were identified in each arm without significant differences in demographics, preoperative variables, medical history, tumor pathology, tumor characteristics, or Iwate score. Regarding intra- and postoperative outcomes, the rebotic approach had significantly less estimated blood loss (EBL) (100 ml [IQR 200 ml] vs 200 ml [IQR 235 ml]; p = 0.029), fewer conversions to open operations (n = 4 [2.4 %] vs n = 13, [7.9 %]; p = 0.043), and a shorter hospital stay (6 days [IQR 3 days] vs 7 days [IQR 3.3 days]; p = 0.009).

CONCLUSION

Both techniques are safe and feasible in major hepatic resections. Compared with L-LH/L-ELH, R-LH/R-ELH is associated with less EBL, fewer conversions to open operations, and a shorter hospital stay.

Laparoscopic versus open caudate lobe liver resections: a 1:2 propensity score-matched controlled study based on a single institution experience

BACKGROUND

Despite the wide use of laparoscopy for liver resection, laparoscopic caudate lobe resections(L-CLR) remain technically challenging, only attempted by experts in the field. The primary objective of this study was to determine the safety and compare the perioperative outcomes of L-CLR with O-CLR based on our single institution experience in a 1:2 propensity score-matched controlled study based on our single institution experience.

METHODS

Between 2004 and 2020, 67 consecutive patients who underwent CLR at Singapore General Hospital were identified. Propensity score matching (PSM) of laparoscopic versus open caudate lobe resections(O-CLR) was performed in a 1:2 ratio with no replacements using nearest neighbour matching method.

RESULTS

L-CLR was associated with a significantly decreased median blood loss (150 mL versus 500 mL, P = 0.001) and a decreased median post-operative stay (3 days versus 7.5 days, P = <0.01) in the unmatched cohorts. After 1:2 propensity score matching, these results were again demonstrated with a significantly lower blood loss (150 mL versus 400 mL, P = 0.016) and a shorter postoperative stay (3 days versus 7 days, P = <0.01) in favour of L-CLR. 30-day readmission and major morbidity (Clavien-Dindo grade > 2) rates were all in favour of L-CLR as well but could not reach statistical significance.

CONCLUSION

L-CLR can be safely performed by experienced surgeons. It is associated with decreased blood loss and shorter perioperative stay compared to O-CLR.

Minimally-invasive versus open pancreatoduodenectomies with vascular resection: A 1:1 propensity-matched comparison study

Background:

Minimally invasive pancreatic pancreatoduodenectomy (MIPD) is increasingly adopted worldwide and its potential advantages include reduced hospital stay and decrease pain. However, evidence supporting the role of MIPD for tumours requiring vascular reconstruction remains limited and requires further evaluation. This study aims to investigate the safety and efficacy of MIPD with vascular resection (MIPDV) by performing a 1:1 propensity-score matched (PSM) comparison with open pancreatoduodenectomy with vascular resection (OPDV) based on a single surgeon's experience.

Methods:

This is a retrospective review of 41 patients who underwent PDV between 2011 and 2020 by a single surgeon. After PSM, the comparison was made between 13 MIPDV and 13 OPDV.

Results:

Thirty-six patients underwent venous reconstruction (VR) only and 5 underwent arterial reconstruction of which 4 had concomitant VR. The types of VR included 22 wedge resections with primary repair, 8 segmental resections with primary anastomosis and 11 requiring interposition grafts. Post-operative pancreatic fistula (POPF) occurred in 3 (7.3%) patients. Major complications (>Grade 2) occurred in 16 (39%) patients, of which 7 were due to delayed gastric emptying requiring nasojejunal tube placement. There was 1 (2.4%) 30-day mortality (OPDV). Of the 13 MIPDV, there were 3 (23.1%) open conversions. PSM comparison demonstrated that MIPDV was associated with longer median operative time (720 min vs. 485 min (P = 0.018). There was no statistically significant difference in other key perioperative outcomes such as intra-operative blood loss, overall morbidity, major morbidity rate, POPF and length of stay.

Conclusion:

Our initial experience with the adoption MIPDV has demonstrated it to be safe with comparable outcomes to OPDV despite the longer operation time.

Impact of non-liver-related previous abdominal surgery on the difficulty of minimally invasive liver resections: a propensity score-matched controlled study

INTRODUCTION

The presence of previous abdominal surgery (PAS) has traditionally been considered to add difficulty to and increase risk of complications of laparoscopic procedures. This study aims to analyse the impact of non-liver-related PAS on the difficulty of minimally invasive liver resections (MILRs).

MATERIALS AND METHODS

After exclusion of patients with concomitant major surgical procedures as well as previous liver resections, 515 consecutive patients undergoing MILR in Singapore General Hospital from 2006 to 2019 were analysed, consisting of 161 MILR in patients with previous abdominal surgery (WPAS) and 354 MILR in patients without previous abdominal surgery (WOPAS). Propensity score-matched (PSM) comparison was performed between WPAS and WOPAS groups. In addition, subgroup analysis was made comparing previous upper or lower abdominal surgery and open versus minimally invasive approach of PAS. Outcomes measured include those associated with operative difficulty such as open conversion rates, operative time, blood loss, as well as morbidity and mortality rates.

RESULTS

MILR outcomes in patients WPAS are not inferior to those WOPAS. Overall open conversion rate was 8.2%, higher in patients WOPAS compared to patients WPAS (11.9% versus 3.5%, p = 0.015). Operating time (p = 0.942), blood loss (p = 0.063), intraoperative blood transfusion (p = 0.750), length of hospital stay (p = 0.206), morbidity (p = 0.217) and 30- and 90-day mortality (p = 1 & p = 0.367) were comparable between the two groups and subgroup analysis.

CONCLUSION

Outcomes of MILR in patients with previous non-liver-related abdominal surgery are not inferior to patients without previous abdominal surgery.

[Etiological analysis on patients with vertigo or dizziness]

Objective: To explore the spectrum of causes for patients with vertigo or dizziness in the Department of Neurology, and provide a reference for diagnosis and treatment of patients with vertigo or dizziness. Methods: Clinical data of patients in the Department of Neurology, Baotou Central Hospital between January 2016 and September 2017 was retrospectively analyzed. The target group under study was diagnosed based on the uniform diagnostic criteria. Results: A total of 9 200 patients with a chief complaint of vertigo or dizziness were included. The ratio of male to female was 1∶1.8, with an age range of 19 to 85 years. The different etiology was as follows: benign paroxysmal positional vertigo (BPPV) (3 148 cases, 34.22%), persistent postural-perceptual dizziness (PPPD) (2 006 cases, 21.80%), vertigo caused by cerebrovascular diseases (1 463 cases, 15.90%), vestibular neuritis (741 cases, 8.05%), vestibular migraine (536 cases, 5.83%), vestibular paroxysmia (336 cases, 3.65%), Ménière disease (187 cases, 2.03%), drug-induced vertigo (96 cases, 1.04%), neurological degenerative diseases (74 cases, 0.80%), sudden sensorineural hearing loss (51 cases, 0.55%), multiple sclerosis and neuromyelitis optica (21 cases, 0.23%), other reasons (22 cases, 0.24%), unknown reasons (519 cases, 5.64%). Conclusions: Dizziness is resulted from various causes, and BPPV is the most common reason. Vertigo caused by cerebrovascular diseases appears to gradually increase along with age. PPPD is very common in clinical practice, so clinicians needs to be highly aware of BPPV and PPPD. Although those dizziness diseases have a low incidence, they should not be ignored. There are still certain proportion of vertigo patients whose diagnosis are undetermined.

Going Forward with Pokemon Go

Pokemon Go is an augmented reality (AR) game which combines the use of smart mobile technology with physical exploration in the real world. It was a global phenomenon that rocked the world since 2016. Across boundaries and nations, the young and seniors were actively downloading and playing, joining the intrend gaming community. Was it a fleeting fad or a more sustainable activity? This paper discusses the literature currently available on this interesting phenomenon: its effect on physical and mental health as well as some documented hazards and distractions. From the review, Pokemon Go demonstrates that cleverly implemented AR games can reach millions of people and trigger substantial behavioral changes. AR games can help increase physical activities and exercise provided people's interest can be sustained.

Diagnostic performance of conventional MRI parameters and apparent diffusion coefficient values in differentiating between benign and malignant soft-tissue tumours

AIM

To compare the abilities of conventional magnetic resonance imaging (MRI) and apparent diffusion coefficient (ADC) in differentiating between benign and malignant soft-tissue tumours (STT).

MATERIAL AND METHODS

A total of 123 patients with STT who underwent 3 T MRI, including diffusion-weighted imaging (DWI), were retrospectively analysed using variate conventional MRI parameters, ADC_mean and ADC_min.

RESULTS

For the all-STT group, the correlation between the malignant STT conventional MRI parameters, except deep compartment involvement, compared to those of benign STT were statistically significant with univariate analysis. Maximum diameter of the tumour (p=0.001; odds ratio [OR], 8.97) and ADC_mean (p=0.020; OR, 4.30) were independent factors with multivariate analysis. For the non-myxoid non-haemosiderin STT group, signal heterogeneity on axial T1-weighted imaging (T1WI; p=0.017), ADC_mean, and ADC_min (p=0.001, p=0.001), showed significant differences with univariate analysis between malignancy and benignity. Signal heterogeneity in axial T1WI (p=0.025; OR, 12.64) and ADC_mean (p=0.004; OR, 33.15) were independent factors with multivariate analysis.

CONCLUSION

ADC values as well as conventional MRI parameters were useful in differentiating between benign and malignant STT. The ADC_mean was the most powerful diagnostic parameter in non-myxoid non-haemosiderin STT.

Gestural praxis in young adults with mild to moderate intellectual disabilities

BACKGROUND

Praxis functioning in the population with intellectual disabilities (ID) has been poorly studied. The goal of this research was to look for a starting point to study the praxic functioning in young adults with mild to moderate ID.

METHOD

Thirty young adults with ID and 30 young adults without ID, between the ages of 18 and 35 years, participated in this study. All participants completed tests that assessed gestural praxis.

RESULTS

It was possible to observe similar praxis behaviour in the group with ID in almost all domains studied, albeit showing statistical values lower than those of the group without ID.

DISCUSSIONS

Despite the high number of errors committed, the sample of participants with ID was able to reach the goal of praxic tasks performed; such errors may be associated with a deficit in the development of various brain functions and not only with praxis functioning, mainly related to a lower yield in terms of planning, monitoring and correcting intentional movement.

In-silico prediction of blood-brain barrier permeability

The ability of penetration of the blood-brain barrier is one of the significant properties of a drug or drug-like compound for the central nervous system (CNS), which is commonly expressed by log BB (log BB = log (C (brain)/C (blood))). In this work, a dataset of 320 compounds with log BB values was split into a training set including 198 compounds and a test set including 122 compounds according to their structure properties by a Kohonen's self-organizing map (SOM). Each molecule was represented by global and shape descriptors, 2D autocorrelation descriptors and RDF descriptors calculated by ADRIANA.Code. Several quantitative models for prediction of log BB were built by a multilinear regression (MLR), a support vector machine (SVM) and an artificial neural network (ANN) analysis. The models show good prediction performance on the test set compounds.

Clinical and molecular epidemiology of extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella pneumoniae in a long-term study from Japan

The detection rates of extended-spectrum β-lactamase (ESBL)-producing bacteria in Japan are very low (∼5%) compared with those obtained worldwide. Further, the current trend of these bacteria in Japan is not known, and few studies with longitudinal observations have been reported. To obtain epidemiologic data on ESBL-producing bacteria, their genotypic features, and their antibiotic resistance patterns in Japan, we analyzed bacterial isolates from hospitalized patients at our institution over the 7-year period from 2003 to 2009. Of 2,304 isolates, 202 (8.8%) were found to be ESBL producers, including Escherichia coli, Klebsiella pneumonia, and Proteus mirabilis. The detection rates of the ESBL-producing isolates gradually increased and reached 17.1% and 10.5% for the E. coli and K. pneumoniae strains, respectively, in 2009. Genotyping analysis showed that ∼90% of the ESBL-producing isolates carried the CTX-M genotype, in which the CTX-M-9 group was predominant, although the CTX-M-2 group is considered to be the main genotype in Japan; further, many of the strains produced multiple β-lactamases. The detection rates of ESBL-producing bacteria may tend to be high within a limited region in Japan. A countrywide survey is required to understand the trend for ESBL-producing bacteria at the national level. In addition, our findings suggest that the genotypes of the detected ESBL producers are similar to those exhibiting a successful nosocomial spread worldwide.

Surveillance of antibiotic resistance in Neisseria gonorrhoeae in the WHO Western Pacific and South East Asian regions, 2007-2008

Long-term surveillance of antimicrobial resistance in Neisseria gonorrhoeae has been conducted in the World Health Organization (WHO) Western Pacific Region (WPR) to optimise antibiotic treatment of gonococcal disease since 1992. In 2007 and 2008, this Gonococcal Antimicrobial Surveillance Programme (GASP) was enhanced by the inclusion of data from the South East Asian Region (SEAR) and recruitment of additional centres within the WPR. Approximately 17,450 N. gonorrhoeae were examined for their susceptibility to one or more antibiotics used for the treatment of gonorrhoea by external quality controlled methods in 24 reporting centres in 20 countries and/or jurisdictions. A high proportion of penicillin and/or quinolone resistance was again detected amongst isolates tested in North Asia and the WHO SEAR, but much lower rates of penicillin resistance and little quinolone resistance was present in most of the Pacific Island countries. The proportion of gonococci reported as 'resistant', 'less susceptible' or 'non-susceptible' gonococci to the third-generation cephalosporin antibiotic ceftriaxone lay in a wide range, but no major changes were evident in cephalosporin minimal inhibitory concentration (MIC) patterns in 2007-2008. Altered cephalosporin susceptibility was associated with treatment failures following therapy with oral third-generation cephalosporins. There is a need for revision and clarification of some of the in vitro criteria that are currently used to categorise the clinical importance of gonococci with different ceftriaxone and oral cephalosporin MIC levels. The number of instances of spectinomycin resistance remained low. A high proportion of strains tested continued to exhibit a form of plasmid mediated high level resistance to tetracyclines. The continuing emergence and spread of antibiotic resistant gonococci in and from the WHO WPR and SEAR supports the need for gonococcal antimicrobial resistance surveillance programs such as GASP to be maintained and potentially expanded.

Identification of potential influenza virus endonuclease inhibitors through virtual screening based on the 3D-QSAR model

Influenza endonucleases have appeared as an attractive target of antiviral therapy for influenza infection. With the purpose of designing a novel antiviral agent with enhanced biological activities against influenza endonuclease, a three-dimensional quantitative structure-activity relationships (3D-QSAR) model was generated based on 34 influenza endonuclease inhibitors. The comparative molecular similarity index analysis (CoMSIA) with a steric, electrostatic and hydrophobic (SEH) model showed the best correlative and predictive capability (q(2) = 0.763, r(2) = 0.969 and F = 174.785), which provided a pharmacophore composed of the electronegative moiety as well as the bulky hydrophobic group. The CoMSIA model was used as a pharmacophore query in the UNITY search of the ChemDiv compound library to give virtual active compounds. The 3D-QSAR model was then used to predict the activity of the selected compounds, which identified three compounds as the most likely inhibitor candidates.

Evaluation of the Hodge test and the imipenem-EDTA double-disk synergy test for differentiating metallo-beta-lactamase-producing isolates of Pseudomonas spp. and Acinetobacter spp

Gram-negative bacilli with acquired metallo-beta-lactamase (MBL) production have been increasingly reported in some countries, necessitating their detection. The aim of this study was to evaluate the performance of the Hodge test and those of the imipenem (IPM)-EDTA, ceftazidime (CAZ)-mercaptopropionic acid (MPA), and CAZ-sodium mercaptoacetic acid (SMA) double-disk synergy tests (DDSTs). The efficiencies of testing CAZ-resistant and IPM-nonsusceptible isolates were also compared. Strains used for the evaluation were known IMP-1 and VIM-2 MBL-producing isolates and consecutive and CAZ-nonsusceptible isolates of pseudomonads and acinetobacters. The performance of the Hodge test was improved by addition of zinc sulfate (140 microg/disk) to an IPM disk. In DDSTs, EDTA (ca. 1,900 microg) disks were better at detecting MBL-producing strains among pseudomonads, while MPA (3 microl) and SMA (3 mg) disks performed better for acinetobacters. EDTA (ca. 750 microg)-plus-SMA (ca. 2 mg) disks performed better than EDTA, MPA, or SMA disks with both organisms. CAZ-SMA DDSTs failed to detect 22 of 80 (28%) MBL-producing acinetobacters. In conclusion, use of an IPM disk and an EDTA (750 microg)-plus-SMA (2 mg) disk improves performance, and testing IPM-nonsusceptible isolates rather than CAZ-resistant isolates could reduce screening work. Further evaluation of the test is required for the detection of other types of MBL-producing gram-negative bacilli.

Age-related accumulation of Ig V(H) gene somatic mutations in peripheral B cells from aged humans

To investigate age-related alterations in human humoral immunity, we analysed Ig heavy chain variable region genes expressed by peripheral B cells from young and aged individuals. Three hundred and twenty-seven cDNA sequences, 163 micro and 164 gamma transcripts with VH5 family genes, were analysed for somatic hypermutation and VHDJH recombinational features. Unmutated and mutated micro transcripts were interpreted as being from naive and memory IgM B cells, respectively. In young and aged individuals, the percentages of naive IgM among total micro transcripts were 39% and 42%, respectively. D and JH segment usage in naive IgM from aged individuals was similar to that from young individuals. The mutational frequencies of memory IgM were similar in young and aged individuals. gamma transcripts, which are regarded as being from memory IgG B cells, showed a significantly higher mutational frequency (7.6%) in aged than in young individuals (5.8%) (P < 0.01). These findings suggest that VHDJH recombinational diversity was preserved, but that the accumulation of somatic mutations in the IgG VH region was increased in aged humans. The accumulation of somatic mutations in IgG B cells during ageing may imply that an age-related alteration exists in the selection and/or maintenance of peripheral memory B cells.

The effectiveness of anti-retroviral drug therapy for HIV-1 is associated with HIV-1 proviral DNA levels and viral selection

The effect of combination anti-retroviral therapy regimens on HIV-1 proviral DNA levels in peripheral blood mononuclear cells was examined in 12 HIV-1-positive patients, using endpoint dilution polymerase chain reaction and serial cloning, and sequencing of the gag region of HIV-1. The major clone was defined as the most numerous of 10 analysed clones, and observation periods ranged from 8 months to 32 months (mean 19.7 +/- 10.2 months). In five patients (one with primary-stage HIV-1 infection) receiving three anti-retroviral drugs, HIV-1 RNA reduced to undetectable levels (i.e. < or = 100 copies/ml). HIV-1 proviral DNA and the number of major clones reduced in four of these patients. HIV-1 RNA levels reduced, but remained detectable, in five other patients. In the two remaining patients (both receiving two rather than three anti-retroviral drugs), HIV-1 RNA levels increased. These results suggest that the population of major clones may be affected when HIV-1 RNA levels reduce following combination regimens of anti-retroviral therapy.

Genistein prevents nuclear factor-kappa B activation and acute lung injury induced by lipopolysaccharide

Protein tyrosine kinase (PTK) inhibitors have been proposed to reduce lung injury and lethal toxicity. The mechanisms responsible for the effects of PTK inhibitors remain obscure. The purpose of the present study was to examine whether genistein, a specific inhibitor of PTK, inhibits nuclear factor-kappa B (NF-kappaB) activation during acute lung injury induced by lipopolysaccharide (LPS) and, if so, to enumerate the effects of inhibition of NF-kappaB activation on LPS-induced proinflammatory gene products, such as cytokine-inducible neutrophil chemoattractant (CINC) and matrix metalloproteinase-9 (MMP-9), as well as neutrophil influx into the lungs. Intratracheal treatment of rats with LPS (6 mg/kg) resulted in increases in total protein and lactate dehydrogenase activity in bronchoalveolar lavage fluid and activated DNA-binding activity of NF-kappaB in alveolar macrophages and lung tissue. A 2-h pretreatment with genistein (50 mg/kg, intraperitoneally) inhibited the LPS-induced changes in lung injury parameters and the induction of NF-kappaB activation. Furthermore, these inhibitory effects of genistein correlated with a depression of LPS-induced protein tyrosine phosphorylation (approximately molecular masses of 46, 48, and 54 kD) and phosphorylation of Jun N-terminal kinase (JNK) in lung tissue. Genistein also substantially reduced the LPS-induced CINC production and MMP-9 activity and suppressed neutrophil recruitment. These results suggest that genistein attenuates LPS-induced acute lung responses through inhibition of NF-kappaB activation. In addition, NF-kappaB activation appears to be an important mechanism mediating LPS-induced CINC production and MMP-9 activity and resulting neutrophil recruitment associated with acute lung inflammation and injury.

Evidence of B cell clonal expansion in HIV type 1-infected patients

HIV-1 infection results in a gradual decrease in CD4(+) T cell counts and progressive immune deficiency. Increased T cell turnover in HIV-1-infected patients, which can be interpreted as T cell clonal expansion, has been thought to be relevant to its pathogenesis. To investigate whether B cell clonal expansion also occurs in HIV-1-infected patients, we examined the expressed V(H)DJ(H) gene sequences of peripheral B cells in HIV-1-infected patients with hypergammaglobulinemia. Identical V(H)DJ(H) gene rearrangements with additional nucleotide differences in V(H) genes were analyzed as a marker of clonally related B cells. From healthy individuals and HIV-1-uninfected patients with hypergammaglobulinemia, clonally related B cells were detected in none of 10 (0%) and 2 of 10 (20%), respectively. No clonally related B cells were detected in any of the nine HIV-1-infected patients with detectable viral loads and normal Ig levels (0%). In contrast, from 9 of 14 HIV-1-infected patients with hypergammaglobulinemia (64%), clonally related B cells were detected. In addition, no HIV-1-infected patients who exhibited normal Ig levels after antiretroviral therapy had clonally related B cells. These findings suggest that B cell clonal expansion is present in HIV-1-infected patients with hypergammaglobulinemia.

Hepatitis B virus genomes of chronic hepatitis patients do not contain specific mutations related to acute exacerbation

To determine the specific viral variants associated with acute exacerbation of chronic hepatitis from hepatitis B virus (HBV) infection, we analyzed the complete nucleotide sequences of the HBV genome in serial serum samples from two chronic active hepatitis patients who seroconverted from HBeAg to anti-HBe. HBV DNA was amplified by polymerase chain reaction (PCR) and sequenced. A 1896 precore stop codon mutant (G to A at nt 1896) coexisting with the wild sequence was found in both patients prior to seroconversion from HBeAg to anti-HBe. Core promoter mutations at nucleotide positions 1762 (A to T) and 1764 (G to A) were found in both patients throughout the observation period. Mutations were observed in the HBV genome of the two patients at different time points, and there was no correlation between the mutations and liver disease or DNA polymerase levels. The nucleotide divergence rate and the composition of quasispecies in the HBV sequence at the time of acute exacerbation were almost the same as were found at other time points. These results suggest that acute exacerbation does not appear to be caused by a characteristic HBV species. The multiple factors that cause generalized HBV replication activation may contribute to acute exacerbation.

Evaluation of efficiency of screening extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae in hospitals where the bacteria are increasingly prevalent

The disk screening methods for extended-spectrum beta-lactamase-producing strains were evaluated. The confirmatory work is reduced significantly in settings such as those in this study, by changing the cefpodoxime breakpoint to < or =20 mm and by not testing cefoxitin-resistant isolates. Cefotaxime and ceftazidime disk screening is reliable, and the laboratory-prepared cefotaxime- and ceftazidime-clavulanic acid disks are stable at -20 degrees C for 12 weeks.

Neonatal intensive care unit outbreak caused by a strain of Klebsiella oxytoca resistant to aztreonam due to overproduction of chromosomal beta-lactamase

Klebsiella oxytoca strains resistant to both aztreonam and ceftriaxone were isolated from six neonates in a neonatal intensive care unit and water reservoirs of two humidifiers attached to the neonatal incubators. These isolates were assumed to be of the same clone because they were characterized by the same antimicrobial susceptibility and pulsed field gel electrophoresis patterns. It was established that the drug resistance was attributed to overproduction of chromosomally encoded Kl beta-lactamase. It was determined that an isolate (K. oxytoca H1) contained a high enzyme concentration (27microg/100microg of protein in enzyme extracts), at least 27 times higher than the control K. oxytoca N1. It was also demonstrated that isolates had a point mutation in the - 35 concensus region of the promotor gene of bla(OXY-2)leading to enzyme overproduction. Outbreaks caused by K1 hyperproducers have not previously been described.

[Effect of highly active antiretroviral therapy (HAART) on hypergammaglobulinemia in HIV infected patients]

To investigate the mechanism of hypergammaglobulinemia in HIV infected patients, the effect of highly active antiretroviral therapy (HAART) on the hypergammaglobulinemia was analyzed. Involved in this study were 34 untreated, 21 HAART-effective (complete response) and 14 HAART-non-effective (partial response) patients. Serum levels of HIV-RNA and gammaglobulin and immunoglobulin (Ig) isotypes were measured. Mean HIV-RNA levels of untreated and partial response patients were 1.6 x 10(4) copies/ml and 0.4 x 10(4) copies/ml, respectively. HIV-RNA levels of all complete response patients were below 4.0 x 10(2) copies/ml. Mean gammaglobulin percentages of untreated, partial response and complete response patients were 24.4%, 21.8% and 17.9%, respectively (p < 0.01 in untreated vs complete response patients). Mean IgG levels in the three groups were 2,489 mg/dl, 1,947 mg/dl and 1,618 mg/dl, respectively (p < 0.001 in untreated vs complete response patients). IgA levels were high in some untreated patients and lower in complete response patients. IgE levels were increased in some untreated and partial response patients, but there was no significant difference among the three groups. These results suggested that the hypergammaglobulinemia found in HIV infected patients was associated with HIV replication. The activation mechanism might differ by Ig isotypes.

Antimicrobial resistance surveillance of bacteria in 1999 in Korea with a special reference to resistance of enterococci to vancomycin and gram-negative bacilli to third generation cephalosporin, imipenem, and fluoroquinolone

The trend of antimicrobial resistance of bacteria isolated from patients in 30 Korean hospitals in 1999 was analyzed with a particular attention to cefotaxime- or fluoroquinolone-resistant gram-negative bacilli, imipenem-resistant Pseudomonas aeruginosa, and vancomycin-resistant enterococci. Adequacy of susceptibility testing, and any change in the frequencies of isolated species were also analyzed. The results showed that only 20% and 30% of hospitals tested the piperacillin-tazobactam and cefoxitin susceptibility of Enterobacteriaceae, respectively, only 24% of hospitals the piperacillin-tazobactam susceptibility of P. aeruginosa, and 17% of hospitals the fusidic acid susceptibility of staphylococci. Among the isolates 26.3% were glucose-nonfermenting gram-negative bacilli, and 34.7% of Enterococcus were Enterococcus faecium. Slight decline of cefotaxime-resistance rate to 20% was noted in Klebsiella pneumoniae, while fluoroquinolone-resistance rate was 68% in Acinetobacter baumannii. The ceftazidime- and imipenem-resistance rates were 17% and 18%, respectively in P. aeruginosa. The vancomycin-resistance rate of E. faecium rose significantly to 15.1%, but the rates varied significantly depending on hospitals suggesting presence of different degree of selective pressure or nosocomial spread. In conclusion, the prevalence of imipenem-resistant P. aeruginosa and the increase of vancomycin-resistant E. faecium were the particularly worrisome phenomena observed in this study.

Solid phase synthesis of carbocyclic l-2'-deoxynucleosides

[reaction: see text] Carbocyclic L-2'deoxynucleosides 17 were synthesized on solid phase in four steps from the appropriately protected intermedate 11. The Mitsunobu reaction was used as a condensation method between the carbocyclic moiety and heterocyclic bases. The regioselectivity of the carbocyclic nucleosides was compared between the solid and solution phase syntheses.

2'-Ribose-ferrocene oligonucleotides for electronic detection of nucleic acids

We have synthesized two novel phosphoramidites with a ferrocenyl moiety at the 2'-ribose position linked through a butoxy linker. Using automated DNA/RNA synthesis techniques, oligonucleotides containing ferrocene at various positions were prepared and characterized by HPLC, MALDI-TOF mass spectrometry, and electrochemistry. Thermal stability studies of the ferrocene-modified DNA duplexes revealed that introduction of one or two ferrocenyl complexes does not result in an observed change of the T(m) values of the corresponding DNA duplexes when compared to the nonmodified hybrids. These data indicate that the introduction of a ferrocenyl group at the 2'-position of the ribose ring containing either a purine or pyrimidine base has no effect on the stability of the modified DNA. The electrochemical behavior of the ferrocene-containing DNA was examined by cyclic voltammetry. The modified 2'-ferrocene-oligonucleotides are electrochemically active and can be used as signaling probes for the electronic detection of nucleic acids on bioelectronic sensors.

A two year global evaluation of the susceptibility of Candida species to fluconazole by disk diffusion

The in-vitro activity of fluconazole against 46,831 yeast isolates collected over a two-year period from 57 laboratories in 33 countries worldwide was assessed using a disc diffusion method. Candida albicans was the organism isolated most frequently, accounting for 68.6% of the total number of isolates. C. glabrata, C. tropicalis, C parapsilosis and C. krusei and Cryptococcus neoformans represented 9.9, 4.7, 4.3, 1.9, and 1.4% of isolates respectively during the 2 year period and rates varied markedly between countries. In 1999 data blood isolates represented 4.9% of all isolates and intensive care unit isolates represented 9.9%. In both the 1998 and 1999 data, 99% of C. albicans were fully susceptible (S) to fluconazole, and 95.6% of all species of yeasts tested were S or susceptible-dose dependent (S-DD) to fluconazole. No emerging trends of resistance were noted with any of the Candida spp. tested as 96% of all isolates retained susceptibility (S or S-DD) to this agent.

Understanding the mode of action of L-nucleosides as antiviral agents: a molecular modeling approach

Computer modeling studies have been performed on the several pairs of D- and L-nucleoside inhibitors with the HIV-1 RT model. Additionally, clinically important M184V mutation, which confers the viral resistance against 3TC and FTC, were studied by the same modeling system.

Present situation of antimicrobial resistance in Korea

Resistance of bacteria to antimicrobial agents is a worldwide concern. In Korea, resistant bacteria are more prevalent than in other industrialized countries. Methicillin-resistant Staphylococcus aureus, erythromycin-resistant Streptococcus pyogenes, penicillin non-susceptible pneumococci, beta-lactamase-producing gonococci, extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae, class C beta-lactamase-producing E. coli, fluoroquinolone-resistant E. coli, and aminoglycoside-resistant Acinetobacter baumannii and Pseudomonas aeruginosa are examples of resistant bacteria prevalent in Korea, and their presence suggests a high level of antimicrobial selective pressure and the nosocomial spread of resistant bacteria. Recently observed rapid increases in the incidence of vancomycin-resistant Enterococcus faecium and carbapenem-resistant P. aeruginosa present new threats in Korea.

Bioelectronic detection of point mutations using discrimination of the H63D polymorphism of the Hfe gene as a model

BACKGROUND

A bioelectronic detection platform has recently been developed that facilitates the detection and characterization of nucleic acids. The DNA chip platform is compatible with homogeneous assays because separate labeling and wash steps are not required. A one-step, bioelectronic detection assay was developed to genotype patient samples with respect to the H63D polymorphism of the Hfe gene, associated with hereditary hemochromatosis.

METHODS AND RESULTS

Electrode arrays were modified with DNA capture probes that were perfectly matched to the wild-type or mutant allele of H63D. Amplicons containing the polymorphic site were hybridized with the capture probes on the electrode arrays in the presence of electronically labeled reporter (signaling) probes. Voltammetric analysis of the electrode arrays was conducted first at ambient temperature and then at elevated temperature. The electronic signal was preferentially diminished at elevated temperature from electrodes that hybridized with mismatched target amplicons.

CONCLUSION

An assay for bioelectronic genotyping of the H63D polymorphism was developed and used with six patient specimens to show the feasibility of this system as a model for point mutation detection.