Low household income increases the risk of tuberculosis recurrence: a retrospective nationwide cohort study in South Korea

OBJECTIVES

We assessed the impact of household income on tuberculosis (TB) recurrence and the long-term impact of TB on household income.

STUDY DESIGN

This was a retrospective nationwide cohort study of patients with drug-susceptible TB (DS-TB) and TB recurrence.

METHODS

Using the South Korean national TB cohort database, we identified a sub-set cohort of patients with newly diagnosed drug-susceptible TB between 2013 and 2016 and tracked their TB recurrence and longitudinal income data from 2007 to 2018. Income levels were evaluated as 'Medical aid' and quintile categories. To assess risk factors associated with TB recurrence, we used a sub-distribution hazard model, adjusting for the competing risks of death.

RESULTS

Of 66,690 patients successfully treated with DS-TB, 2095 (3.1 %) experienced recurrence during a median follow-up of 39 months. The incidence of TB recurrence was 982.1/100,000 person-years, with 50.3 % of the recurrences occurring within 1 year of treatment completion. The risk of TB recurrence increased with decreasing income levels, with the highest risk observed in the lowest income group. The effect of income on TB recurrence was prominent in males but not in females. Overall, patients with TB recurrence experienced a linear decline in income levels, compared with those without recurrence.

CONCLUSIONS

Household income during the initial TB episode was an important risk factor for TB recurrence, particularly in males.

To Test or Not? Xpert MTB/RIF as an Alternative to Smear Microscopy to Guide Line Probe Assay Testing for Drug-Resistant Tuberculosis

Xpert MTB/RIF (Xpert) revolutionized tuberculosis (TB) diagnosis. Laboratory decision making on whether widely-used reflex drug susceptibility assays (MTBDRplus, first-line resistance; MTBDRsl, second-line) are conducted is based on smear status, with smear-negative specimens often excluded. We performed receiver operator characteristic (ROC) curve analyses using bacterial load information (smear microscopy grade, Xpert-generated semi-quantitation categories and minimum cycle threshold [CTmin] values) from Xpert rifampicin-resistant sputum for the prediction of downstream line probe assay results as "likely non-actionable" (no resistance or susceptible results generated). We evaluated actionable-to-non-actionable result ratios and pay-offs with missed resistance versus LPAs done universally. Smear-negatives were more likely than smear-positive specimens to generate a non-actionable MTBDRplus (23% [133/559] versus 4% [15/381]) or MTBDRsl (39% [220/559] versus 12% [47/381]) result. However, excluding smear-negatives would result in missed rapid diagnoses (e.g., only 49% [264/537] of LPA-diagnosable isoniazid resistance would be detected if smear-negatives were omitted). Testing smear-negatives with a semi-quantitation category ≥ "medium" had a high ratio of actionable-to-non-actionable results (12.8 or a 4-fold improvement versus testing all using MTBDRplus, 4.5 or 3-fold improvement for MTBDRsl), which would still capture 64% (168/264) and 77% (34/44) of LPA-detectable smear-negative resistance, respectively. Use of CTmins permitted optimization of this ratio with higher specificity for non-actionable results but decreased resistance detected. Xpert quantitative information permits identification of a smear-negative subset in whom the payoffs of the ratio of actionable-to-non-actionable LPA results with missed resistance may prove acceptable to laboratories, depending on context. Our findings permit the rational expansion of direct DST to certain smear-negative sputum specimens.

Understanding patient-level costs of weekly isoniazid-rifapentine (3HP) among people living with HIV in Uganda

BACKGROUND: Twelve weeks of weekly isoniazid and rifapentine (3HP) prevents TB disease among people with HIV (PWH), but the costs to people of taking TB preventive treatment is not well described.METHODS: We surveyed PWH who initiated 3HP at a large urban HIV/AIDS clinic in Kampala, Uganda, as part of a larger trial. We estimated the cost of one 3HP visit from the patient perspective, including both out-of-pocket costs and estimated lost wages. Costs were reported in 2021 Ugandan shillings (UGX) and US dollars (USD; USD1 = UGX3,587)RESULTS: The survey included 1,655 PWH. The median participant cost of one clinic visit was UGX19,200 (USD5.36), or 38.5% of the median weekly income. Per visit, the cost of transportation was the largest component (median: UGX10,000/USD2.79), followed by lost income (median: UGX4,200/USD1.16) and food (median: UGX2,000/USD0.56). Men reported greater income loss than women (median: UGX6,400/USD1.79 vs. UGX3,300/USD0.93), and participants who lived further than a 30-minute drive to the clinic had higher transportation costs than others (median: UGX14,000/USD3.90 vs. UGX8,000/USD2.23).CONCLUSION: Patient-level costs to receive 3HP accounted for over one-third of weekly income. Patient-centered approaches to averting or defraying these costs are needed.

The short-term effects of fixed copayment policy on elderly health spending and service utilization: evidence from South Korea's age-based policy using exact date of birth

A large number of the poor elderly in Korea have been exposed to the risk of insufficient proper medical treatments because of financial restrictions. South Korea launched policies to reduce the cost-sharing burden on the elderly, including one compelling the elderly to pay a fixed out-of-pocket amount for outpatient treatments. The impacts of such policies, however, have yet to be elucidated. In this paper, we estimate the short-term effects of the fixed outpatient copayment policy on the health-related behavior of the elderly. We employed a regression discontinuity design by using the exact days before and after the sample's 65th birthdate as the assignment variable, along with the restricted individual-level 2012 and 2013 National Health Insurance claims data. Results show that the policy increased the elderly's health service utilization numbers and reduced out-of-pocket spending for insured services. Moreover, the effects on prescription spending and the insurer's burden differed depending on beneficiaries' characteristics.

Cost to perform door-to-door universal sputum screening for TB in a high-burden community

BACKGROUND: Population-based active case-finding (ACF) identifies people with TB in communities but can be costly.METHODS: We conducted an empiric costing study within a door-to-door household ACF campaign in an urban community in Uganda, where all adults, regardless of symptoms, were screened by sputum Xpert Ultra testing. We used a combination of direct observation and self-reported logs to estimate staffing requirements. Study budgets were reviewed to collect costs of overheads, equipment, and consumables. Our primary outcome was the cost per person diagnosed with TB.RESULTS: Over a 28-week period, three teams of two people collected sputum from 11,341 adults, of whom 48 (0.4%) tested positive for TB. Screening 1,000 adults required 258 person-hours of effort at a cost of US$402,000, 70% of which was for GeneXpert cartridges. The estimated cost per person screened was $36 (95% uncertainty range [95% UR] 34-38), and the cost per person diagnosed with Xpert-positive TB was $8,400 (95% UR 8,000-8,900). The prevalence of TB in the underlying community was the primary modifiable determinant of the cost per person diagnosed.CONCLUSION: Door-to-door screening can be feasibly performed at scale, but will require effective triage and identification of high-prevalence populations to be affordable and cost-effective.

Causal Impact of School Starting Age on the Tempo of Childbirths: Evidence from Working Mothers and School Entry Cutoff Using Exact Date of Birth

Many studies show that females' age at first childbirth affects important outcomes of these females and their offspring such as health- and socioeconomic-related variables. This paper analyzes whether there is a causal relationship between working mothers' school entry age and the timing at which they give birth by exploiting Korea's elementary school entry cutoff regulation. Using administrative employment insurance data that record the fertility history of female working mothers together with regression discontinuity design, we find that a year's delay in age at school starting increases age at first and second childbirth by approximately 3 and 4 months, respectively. We also find that one of the mechanisms that affects the relationship between these two variables is age at first employment. The estimated effects of SSA are likely to be salient in a country where educational sequence that a student experience is rigid.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10680-021-09597-x.

Determining the value of TB active case-finding: current evidence and methodological considerations

Active case-finding (ACF) is an important component of the End TB Strategy. However, ACF is resource-intensive, and the economics of ACF are not well-understood. Data on the costs of ACF are limited, with little consistency in the units and methods used to estimate and report costs. Mathematical models to forecast the long-term effects of ACF require empirical measurements of the yield, timing and costs of case detection. Pragmatic trials offer an opportunity to assess the cost-effectiveness of ACF interventions within a 'real-world´ context. However, such analyses generally require early introduction of economic evaluations to enable prospective data collection on resource requirements. Closing the global case-detection gap will require substantial additional resources, including continued investment in innovative technologies. Research is essential to the optimal implementation, cost-effectiveness, and affordability of ACF in high-burden settings. To assess the value of ACF, we must prioritize the collection of high-quality data regarding costs and effectiveness, and link those data to analytical models that are adapted to local settings.

Resource implications of the latent tuberculosis cascade of care: a time and motion study in five countries

BACKGROUND

The End TB Strategy calls for global scale-up of preventive treatment for latent tuberculosis infection (LTBI), but little information is available about the associated human resource requirements. Our study aimed to quantify the healthcare worker (HCW) time needed to perform the tasks associated with each step along the LTBI cascade of care for household contacts of TB patients.

METHODS

We conducted a time and motion (TAM) study between January 2018 and March 2019, in which consenting HCWs were observed throughout a typical workday. The precise time spent was recorded in pre-specified categories of work activities for each step along the cascade. A linear mixed model was fit to estimate the time at each step.

RESULTS

A total of 173 HCWs in Benin, Canada, Ghana, Indonesia, and Vietnam participated. The greatest amount of time was spent for the medical evaluation (median: 11 min; IQR: 6-16), while the least time was spent on reading a tuberculin skin test (TST) (median: 4 min; IQR: 2-9). The greatest variability was seen in the time spent for each medical evaluation, while TST placement and reading showed the least variability. The total time required to complete all steps along the LTBI cascade, from identification of household contacts (HHC) through to treatment initiation ranged from 1.8 h per index TB patient in Vietnam to 5.2 h in Ghana.

CONCLUSIONS

Our findings suggest that the time requirements are very modest to perform each step in the latent TB cascade of care, but to achieve full identification and management of all household contacts will require additional human resources in many settings.

Cost-effectiveness of contact screening strategies for tuberculosis among high-school adolescents in South Korea

BACKGROUND

Effective latent tuberculous infection (LTBI) control among adolescents is a critical component of tuberculosis (TB) elimination in Korea.

OBJECTIVE

To compare the cost-effectiveness of the following contact screening strategies for LTBI among high-school adolescents after TB outbreaks: QuantiFERON®-TB Gold In-Tube (QFT-GIT), the tuberculin skin test (TST), or TST/QFT-GIT (two-step strategy).

METHOD

The costs of post-TB outbreak screening strategies were calculated using a mixed (top-down and bottom-up) cost analysis method and expressed in 2015 US dollars. Cost-effectiveness was evaluated using a decision analysis model from the health system perspective, comparing cumulative health care costs and the total number of TB cases averted.

RESULTS

In a hypothetical cohort of 1000 students, screening using the TST-alone strategy averted 1.6 TB cases at a total cost of US$52 566. The QFT-GIT-alone strategy helped avert 2.0 TB cases, but was associated with a much higher total cost (US$108 435), resulting in an incremental cost-effectiveness ratio of US$140 933/TB case averted. The two-step TST/QFT-GIT strategy was worse than the TST-alone strategy, averting 1.3 TB cases at US$75 267.

CONCLUSION

The TST-alone strategy was the most cost-effective; the QFT-GIT-alone strategy averted the greatest number of TB cases but incurred the highest cost in contact investigation for school TB outbreaks.

Costs and operation management of community outreach program for tuberculosis in tribal populations in India

Objective

To evaluate costs of an active case finding (ACF) program with tuberculosis (TB) treatment delivery and monitoring, which targeted a rural tribal population in India.

Method

A time and motion study was conducted to evaluate operations and workload. Costs from the program perspective were assessed using both the bottom-up and top-down costing methods, exclusive of routine TB care costs. The impact of ACF on routine TB laboratory workloads was measured based on the changes in available staff time per smear at nine designated microscopy centers before and after program implementation.

Results

A majority (53.2%) of the community health-care worker's time was spent in traveling to communities, with an average of 22 TB patients (95% CI 19.14-24.94) seen per day per person. Costs (at 2015 $US rates) were US$1.85-US$2.42 per patient screened and submitting sputum, US$2.51-US$4.74 per person diagnosed with TB, and US$22.52-US$34.13 per TB patient completing treatment. Total smear volumes increased significantly after the ACF program, with more than a 15% reduction in available staff time per sputum smear test in most laboratories.

Conclusion

This low-cost, ACF program has the potential to be highly cost-effective in addressing gaps in TB care problems in rural India.

Causal Impact of Having a College Degree on Women's Fertility: Evidence From Regression Kink Designs

An important factor speculated to affect fertility level is education. Theoretical predictions regarding whether education increases or decreases fertility are ambiguous. This study analyzes the causal impact of higher education on fertility using census data administered by Statistics Korea. To account for the endogeneity of education, this study exploits the Korean higher education reform initiated in 1993 that boosted women's likelihood of graduating from college. Based on regression kink designs, we find that having a college degree reduces the likelihood of childbirths by 23 percentage points and the total number of childbirths by 1.3. Analyses of possible mechanisms show that labor market-related factors are a significant channel driving the negative effects; female college graduates are more likely to be wage earners and more likely to have high-wage occupations.

A graphene mesh as a hybrid electrode for foldable devices

A graphene mesh with arrays of micro-holes was fabricated on a polymer substrate using photolithography for use as an electrode in flexible devices. The optimal mesh structure with high optical transmittance and electrical conductivity was designed using a finite element method, in which the conductivity of the mesh was simulated as a function of structure, size, and periodicity of the hole array. The sheet resistance of the graphene mesh was lowered to that of a graphene monolayer by chemical doping and found to be 330 Ω Sq^-1 at 98.5% transparency. The figure of merit of the doped graphene mesh was calculated to be 106 at 98% transmittance, a value that has not yet been reported for any conventional transparent electrode material. Due to strong bonding between the polymer and substrate, the hybrid electrode composed of a silver nanowire (AgNW)/graphene mesh coated with an over-coating layer exhibited more stable electrical characteristics during mechanical fatigue deformation compared to a hybrid film composed of a AgNW/graphene sheet. The AgNW/graphene sheet underwent breakdown at less than 20 000 cycles in cyclic bending tests with 6.5% strain, but the AgNW/graphene mesh showed a 38% increase in resistance at 20 000 cycles and no breakdown even at 100 000 cycles. Therefore, in this study, we propose a hybrid structure composed of a AgNW/graphene mesh, which is optically and mechanically superior to AgNW/graphene sheets, and therefore suitable for application as a transparent electrode in foldable devices with long-term stability.

Using Synthetic Controls to Evaluate the Effect of Unique Interventions: The Case of Say Yes to Education

BACKGROUND

"Place-based" scholarships seek to improve student outcomes in urban school districts and promote urban revitalization in economically challenged cities. Say Yes to Education is a unique district-wide school reform effort adopted in Syracuse, NY, in 2008. It includes full-tuition scholarships for public and private universities, coupled with extensive wraparound support services in schools.

OBJECTIVES

This study uses synthetic control methods to evaluate the effect of Say Yes on district enrollment and graduation rates. It also introduces the synthetic control method and provides guidance for its use in evaluating single-site interventions.

METHOD

Combining school district-level data from the National Center for Education Statistics' Common Core of Data and New York State School Report Cards, this article uses synthetic control methods to construct a synthetic comparison district to estimate counterfactual enrollment and graduation trends for Syracuse.

RESULTS

We find that Say Yes to Education was associated with enrollment increases in the Syracuse City School District, a district that had previously experienced decades of sustained enrollment declines. We do not find consistent evidence of changes in graduation rates following adoption of the program.

CONCLUSIONS

Graduation rate analyses demonstrate that estimates of treatment effects can be sensitive to choices that the researcher has to make in applying synthetic control methods, particularly when pretreatment outcome measures appear to have considerable amounts of noise.

Isolated, well-defined organovanadium(iii) on silica: single-site catalyst for hydrogenation of alkenes and alkynes

Well-defined, isolated, single-site organovanadium(iii) catalyst on SiO₂ for unprecedented liquid- and gas-phase hydrogenation of alkenes and alkynes under mild conditions.

Treatment of pseudohypoparathyroidism with 1 alpha-hydroxyvitamin D3

A maintenance dosis of 2 microgram/day of 1 alpha-OH-D3 could keep the level of serum calcium normal in all 5 cases with pseudohypoparathyroidism, in contrast with 4.0 +/- 1.26 microgram/day needed for the 11 cases with hypoparathyroidism (8 idiopathic and 3 postoperative). The conspicuous effect of 1 alpha-OH-D3 on pseudohypoparathyroidism is likely to be attributed to the fact that the unresponsiveness of bone tissue to parathyroid hormone is corrected by the action of active vitamin D.

Lithium inhibits growth of intracellular Mycobacterium kansasii through enhancement of macrophage apoptosis

Mycobacterium kansasii (Mk) is an emerging pathogen that causes a pulmonary disease similar to tuberculosis. Macrophage apoptosis contributes to innate host defense against mycobacterial infection. Recent studies have suggested that lithium significantly enhances the cytotoxic activity of death stimuli in many cell types. We examined the effect of lithium on the viability of host cells and intracellular Mk in infected macrophages. Lithium treatment resulted in a substantial reduction in the viability of intracellular Mk in macrophages. Macrophage cell death was significantly enhanced after adding lithium to Mk-infected cells but not after adding to uninfected macrophages. Lithium-enhanced cell death was due to an apoptotic response, as evidenced by augmented DNA fragmentation and caspase activation. Reactive oxygen species were essential for lithium-induced apoptosis. Intracellular scavenging by N-acetylcysteine abrogated the lithium-mediated decrease in intracellular Mk growth as well as apoptosis. These data suggest that lithium is associated with control of intracellular Mk growth through modulation of the apoptotic response in infected macrophages.

A comparison of inflammatory mediator expression between palmoplantar pustulosis and pompholyx

BACKGROUND

Both palmoplantar pustulosis (PPP) and pompholyx are clinically characterized by acute eruptions of vesicles or pustules on the palms or soles.

OBJECTIVES

This study aims to compare the expression of certain inflammatory mediator genes and proteins between patients with PPP and pompholyx using skin tissue samples.

METHODS

Skin biopsies obtained from lesional skin from patients with PPP (n = 7) and pompholyx (n = 5) were analysed by quantitative RT-PCR to measure the mRNA levels of nine genes, including IL-4, IL-8, IL-9, IL-17, IL-22, IFN-γ, CCL-20, granzyme and perforin. For immunohistochemical analysis, 34 paraffin-embedded skin specimens (PPP, n = 22; pompholyx, n = 12) were stained with anti-IL-8, IL-17A, IL-22 and granzyme B antibodies.

RESULTS

Of genes analysed, IL-8 and IL-17A mRNA expression levels were significantly higher in the PPP group than the pompholyx group (P = 0.012 in both), whereas the mRNA expression of granzyme B was significantly higher in pompholyx when compared with PPP (P = 0.004). Regarding the IL-17A immunohistochemical staining, tissue from the PPP lesions contained significantly more IL-17A(+) cells in both the epidermis and papillary dermis when compared with pompholyx (P < 0.001 and P = 0.019 respectively). Moreover, the intensity of the IL-8 immunoreactivity was also greater in the PPP skin lesions than the pompholyx tissue (P < 0.001).

CONCLUSIONS

IL-8 and IL-17A, both are increased in PPP tissue, may represent important immunologic mediators that help to differentiate this clinical entity from pompholyx. This study may provide useful clues in distinguishing PPP from pompholyx, as well as helping to understand the pathogeneses of these two diseases.

Mycobacterium tuberculosis Rv0652 stimulates production of tumour necrosis factor and monocytes chemoattractant protein-1 in macrophages through the Toll-like receptor 4 pathway

Mycobacterial proteins interact with host macrophages and modulate their functions and cytokine gene expression profile. The protein Rv0652 is abundant in culture filtrates of Mycobacterium tuberculosis K-strain, which belongs to the Beijing family, compared with levels in the H37Rv and CDC1551 strains. Rv0652 induces strong antibody responses in patients with active tuberculosis. We investigated pro-inflammatory cytokine production induced by Rv0652 in murine macrophages and the roles of signalling pathways. In RAW264.7 cells and bone marrow-derived macrophages, recombinant Rv0652 induced predominantly tumour necrosis factor (TNF) and monocyte chemoattractant protein (MCP)-1 production, which was dependent on mitogen-activated protein kinases and nuclear factor-κB. Specific signalling pathway inhibitors revealed that the extracellular signal-regulated kinase 1/2 (ERK1/2), p38 and phosphatidylinositol 3-kinase (PI3K) pathways were essential for Rv0652-induced TNF production, whereas the ERK1/2 and PI3K pathways, but not the p38 pathway, were critical for MCP-1 production in macrophages. Rv0652-stimulated TNF and MCP-1 secretion by macrophages occurred in a Toll-like receptor 4-dependent and MyD88-dependent manner. In addition, Rv0652 significantly up-regulated the expression of the mannose receptor, CD80, CD86 and MHC class II molecules. These results suggest that Rv0652 can induce a protective immunity against M. tuberculosis through the macrophage activation.

Targeting of Mycobacterium tuberculosis heparin-binding hemagglutinin to mitochondria in macrophages

Mycobacterium tuberculosis heparin-binding hemagglutinin (HBHA), a virulence factor involved in extrapulmonary dissemination and a strong diagnostic antigen against tuberculosis, is both surface-associated and secreted. The role of HBHA in macrophages during M. tuberculosis infection, however, is less well known. Here, we show that recombinant HBHA produced by Mycobacterium smegmatis effectively induces apoptosis in murine macrophages. DNA fragmentation, nuclear condensation, caspase activation, and poly (ADP-ribose) polymerase cleavage were observed in apoptotic macrophages treated with HBHA. Enhanced reactive oxygen species (ROS) production and Bax activation were essential for HBHA-induced apoptosis, as evidenced by a restoration of the viability of macrophages pretreated with N-acetylcysteine, a potent ROS scavenger, or transfected with Bax siRNA. HBHA is targeted to the mitochondrial compartment of HBHA-treated and M. tuberculosis-infected macrophages. Dissipation of the mitochondrial transmembrane potential (ΔΨ_m) and depletion of cytochrome c also occurred in both macrophages and isolated mitochondria treated with HBHA. Disruption of HBHA gene led to the restoration of ΔΨ_m impairment in infected macrophages, resulting in reduced apoptosis. Taken together, our data suggest that HBHA may act as a strong pathogenic factor to cause apoptosis of professional phagocytes infected with M. tuberculosis.

Cell death is a common outcome during infection with a number of pathogenic microorganisms. Therefore, defining the factors responsible for killing of host cells is important to uncovering mechanisms of pathogenesis. World-wide, two billon people are latently infected with Mycobacterium tuberculosis, which is still killing 2–3 million people each year. Heparin-binding hemagglutinin (HBHA) protein of M. tuberculosis is known to interact specifically with non-phagocytic cells and to be involved in dissemination from lungs to other tissues. Nevertheless, the role of HBHA in phagocytic cells such as macrophages, which are the first cells of the immune system to encounter inhaled pathogens, has been unknown. In the present study, we suggest HBHA as a critical bacterial protein for macrophage cell death. After M. tuberculosis infection or HBHA treatment of macrophages, HBHA targeted to mitochondria and then caused mitochondrial damage and oxidative stress, which eventually lead to apoptosis. A mutant of M. tuberculosis lacking HBHA induced less apoptosis with moderated mitochondrial damage. These experiments provide a candidate virulence factor which may be a novel target for tuberculosis treatment.

Comparative cost and performance of light-emitting diode microscopy in HIV-tuberculosis-co-infected patients

Light-emitting diode (LED) microscopy has recently been endorsed by the World Health Organization (WHO). However, it is unclear whether LED is as accurate and cost-effective as Ziehl-Neelsen (ZN) microscopy or mercury vapour fluorescence microscopy (MVFM) in tuberculosis (TB)-HIV-co-infected subjects. Direct and concentrated sputum smears from TB suspects were evaluated using combinations of LED microscopy, ZN microscopy and MVFM. Median reading time per slide was recorded and a cost analysis performed. Mycobacterial culture served as the reference standard. 647 sputum samples were obtained from 354 patients (88 (29.8%) were HIV-infected and 161 (26%) were culture-positive for Mycobacterium tuberculosis). Although overall sensitivity of LED compared with ZN microscopy or MVFM was similar, sensitivity of all three modalities was lower in HIV-infected patients. In the HIV-infected group, the sensitivity of LED microscopy was higher than ZN microscopy using samples that were not concentrated (46 versus 39%; p = 0.25), and better than MVFM using concentrated samples (56 versus 44; p = 0.5). A similar trend was seen in the CD4 count <200 cells · mL(-1) subgroup. Median (interquartile range) reading time was quicker with LED compared with ZN microscopy (1.8 (1.7-1.9) versus 2.5 (2.2-2.7) min; p ≤ 0.001). Average cost per slide read was less for LED microscopy (US$1.63) compared with ZN microscopy (US$2.10). Among HIV-TB-co-infected patients, LED microscopy was cheaper and performed as well as ZN microscopy or MVFM independent of the staining (ZN or auramine O) or processing methods used.

Conversion of Mycobacterium smegmatis to a pathogenic phenotype via passage of epithelial cells during macrophage infection

Mycobacteria encounter many different cells during infection within their hosts. Although alveolar epithelial cells play an essential role in host defense as the first cells to be challenged upon contact with mycobacteria, they may contribute to the acquisition of mycobacterial virulence by increasing the expression of virulence or adaptation factors prior to being ingested by macrophages on the side of pathogens. From this aspect, the enhanced virulence of nonpathogenic Mycobacterium smegmatis (MSM) passed through human alveolar A549 epithelial cells (A-MSM) was compared to the direct infection of MSM (D-MSM) in THP-1 macrophages and mouse models. The intracellular growth rate and cytotoxicity of A-MSM were significantly increased in THP-1 macrophages. In addition, compared to D-MSM, A-MSM induced relatively greater interleukin (IL)-1β, IL-6, IL-8, IL-12, TNF-α, MIP-1α, and MCP-1 in THP-1 macrophages. As a next step, a more persistent A-MSM infection was observed in a murine infection model with the development of granulomatous inflammation. Finally, 58 genes induced specifically in A-MSM were partially identified by differential expression using a customized amplification library. These gene expressions were simultaneously maintained in THP-1 infection but no changes were observed in D-MSM. Bioinformatic analysis revealed that these genes are involved mainly in bacterial metabolism including energy production and conversion, carbohydrate, amino acid, and lipid transport, and metabolisms. Conclusively, alveolar epithelial cells promoted the conversion of MSM to the virulent phenotype prior to encountering macrophages by activating the genes required for intracellular survival and presenting its pathogenicity.

High virulent clinical isolates of Mycobacterium abscessus from patients with the upper lobe fibrocavitary form of pulmonary disease

Pulmonary disease caused by nontuberculous mycobacteria (NTM), including Mycobacterium abscessus, can be classified into two distinct types of clinical disease; the upper lobe fibrocavitary (UC) form and nodular bronchiectatic (NB) form. However, the relationship between mycobacterial strain virulence and disease type in the pulmonary M. abscessus diseases has not been reported. To determine the differential virulence between strains causing two forms of disease, we obtained clinical isolates from patients with the UC and NB form of pulmonary disease caused by M. abscessus. In present study, we investigated the intracellular growth of clinical isolates in macrophages and their pathogenicity in C57BL/6 mice. For the isolates from the UC form, intracellular macrophage growth was faster and higher levels of cytokines were induced in macrophages than for those from NB form. Moreover, severe lung inflammation was only observed in mice intranasally infected with the isolate from the UC form with the increase of bacterial load. These findings suggest that M. abscessus isolates from the UC form of pulmonary disease are more virulent than those from NB form. This differential virulence of clinical strains may be one of the important factors involved in the determination of the disease form of pulmonary M. abscessus disease.

Induction of cell death in human macrophages by a highly virulent Korean Isolate of Mycobacterium tuberculosis and the virulent strain H37Rv

Recent studies have suggested that virulent strains of Mycobacterium tuberculosis induce apoptosis in macrophages less often than do attenuated strains. K-strain, which belongs to the Beijing family, is the most frequently isolated clinical strain of M. tuberculosis in Korea. In this study, we investigated the differential induction of cell death in human monocytic THP-1 cells by K-strain and H37Rv, a virulent but laboratory-adapted strain of M. tuberculosis. Although no significant difference in growth rate was observed between the cells exposed to K-strain and those exposed to H37Rv, the levels of protective cytokines such as tumour necrosis factor (TNF)-alpha, interleukin (IL)-6 and IL-12p40 were lower in K-strain-infected cells than in H37Rv-infected cells. Cell viability assays showed that both K-strain and H37Rv, but not heat- or streptomycin-killed bacteria, induced THP-1 cell death in a TNF-independent manner. In contrast, double staining with fluorochrome-labelled inhibitors of caspase and propidium iodide and lactate dehydrogenase release assays revealed that K-strain induced significantly higher levels of necrotic cell death, rather than apoptosis, in THP-1 cells than did H37Rv. Anti-apoptotic Bcl-2, Mcl-1, Bfl-1 and Bcl-xL in the cells were significantly upregulated following infection with K-strain compared with H37Rv, whereas Bax was slightly upregulated in response to infection with both H37Rv and K-strain. These results suggest that the highly virulent K-strain keeps cellular apoptosis as a host defense mechanism to a minimum and induces necrosis in macrophages.

Fluorescence microscopy is less expensive than Ziehl-Neelsen microscopy in Thailand

Ziehl-Neelsen (ZN) microscopy is the primary method for acid-fast bacilli examination in resource-limited settings, including Thailand. Despite its considerably improved diagnostic performance, conventional fluorescent microscopy (FM) is rarely used due to its perceived high cost. An evaluation in Thailand found that the total cost of FM operated in the National Tuberculosis Reference Laboratory (NTRL) in Bangkok, Thailand, is similar to that of ZN performed in the NTRL and in four regional Thai laboratories. FM is therefore a cost-effective alternative to ZN in resource-limited settings.

Obesity should not influence the management of appendicitis

BACKGROUND

Obesity implies an adverse effect on outcome after appendectomy. This study aimed to determine whether obese patients with appendicitis should be managed differently than nonobese patients.

METHODS

After appendectomy, all patients were enrolled in a prospective clinical pathway and followed from initial presentation to full outpatient recovery.

RESULTS

In 1 year, 272 adults underwent appendectomy, 55 (22%) of whom were obese. The obese patients were slightly older (35 vs 33 years; p < 0.001). The time to diagnosis (8.5 vs 8.6 h), and the need for computed tomography (CT) scanning (40% vs 49%) was similar in both populations. The obese patients had similar rates of perforation (35% vs 35%) and laparoscopy (47% vs 41%). The median hospital length of stay (LOS) (2 days) and complications, including wound complications (9.1% vs 10.9%) and intraabdominal abscesses (3.6% vs 3.1%), were similar. Subgroup analysis showed a longer LOS for the obese patients with perforation than for the nonobese patients (6 vs 5.5 days; p = 0.036).

CONCLUSION

Obese patients had no greater delay in diagnosis, had no greater need for CT scan, gained no additional benefit from laparoscopy, and did not incur significantly worse outcomes after appendectomy except for an increased LOS among those with perforation.

Functional Proteomics Study Reveals That N-Acetylglucosaminyltransferase V Reinforces the Invasive/Metastatic Potential of Colon Cancer through Aberrant Glycosylation on Tissue Inhibitor of Metalloproteinase-

N-Acetylglucosaminyltransferase-V (GnT-V) has been reported to be up-regulated in invasive/metastatic cancer cells, but a comprehensive understanding of how the transferase correlates with the invasive/metastatic potential is not currently available. Through a glycomics approach, we identified 30 proteins, including tissue inhibitor of metalloproteinase-1 (TIMP-1), as a target protein for GnT-V in human colon cancer cell WiDr. TIMP-1 was aberrantly glycosylated as characterized by the addition of beta1,6-N-acetylglucosamine, polylactosaminylation, and sialylation in GnT-V-overexpressing WiDr cells. Compared with normal TIMP-1, the aberrantly glycosylated TIMP-1 showed the weaker inhibition on both matrix metalloproteinase (MMP)-2 and MMP-9, and this aberrancy was closely associated with cancer cell invasion and metastasis in vivo as well as in vitro. Integrated data, both of TIMP-1 expression level and aberrant glycosylation, could provide important information to aid to improve the clinical outcome of colon cancer patients.

Induction chemotherapy followed by concurrent chemoradiotherapy (CCRT) versus CCRT alone for unresectable stage III non-small cell lung cancer (NSCLC): Randomized phase III trial

7528

Background: We conducted a prospective randomized phase III trial comparing induction chemotherapy followed by concurrent chemoradiotherapy (CCRT) versus immediate CCRT to evaluate whether the addition of induction chemotherapy would result in improved survival. Methods: Patients with unresectable stage III NSCLC, ECOG PS 0–1, and weight loss up to 10% were eligible. They were randomized to receive either induction chemotherapy followed by CCRT (arm A) or immediate CCRT (arm B) after stratification for stage (T4N0–2, T1–3N3, T4N3, and stage IIIA), histology (squamous vs non-squamous), and SCLN positivity. Induction chemotherapy consisted of two cycles of gemcitabine (1,000 mg/m2 D1, D8) and cisplatin (70 mg/m2 D1) q 21days. Chemotherapy during CCRT consisted of 6 cycles of weekly paclitaxel (50 mg/m2) and cisplatin (20 mg/m2). Radiation therapy performed with hypofractionated scheme (2.2 Gy/fraction, once a day) and total dose was 66 Gy. Irradiated volume encompassed gross tumor plus 1.0 cm margin. Results: Between March 2003 and June 2006, 134 patients were enrolled. 92% of patients were male and 60% were age 60 or older. Objective tumor response was obtained in 38% after induction chemotherapy. Response rates after completion of CCRT were 72% (95% CI, 61%–83%) on arm A and 79% (95% CI, 69%–89%) on arm B. Grade 3/4 toxicities during induction chemotherapy consisted mainly of neutropenia (11%/3%). During CCRT, grade 3/4 neutropenia was noted in 8%/5% (arm A) versus in 8%/0% (arm B), grade 3 anemia was 8% vs 0%, grade 3 thrombocytopenia 5% vs 0%, and grade 3 esophagitis 16% vs 16%. At median follow-up of 28 months, median survival was 12.6 months (95% CI, 8.6–16.7 months) on arm A versus 18.2 months (95% CI, 11.7–24.8 months) on arm B (P=0.18). Two year survival estimates was 25% (15%–35%) and 43% (31%–55%), respectively. Median progression free survival was 7.5 months (95% CI, 5.6–9.4 months) on arm A and 11.6 months (95% CI, 9.6–13.6 months) on arm B (P=0.04). Conclusions: The addition of induction chemotherapy to CCRT failed to increase the survival of unresectable stage III NSCLC over immediate CCRT. Moreover, the progression free survival was inferior to immediate CCRT.

No significant financial relationships to disclose.

Phase I/II study of combination chemotherapy with S-1 and cisplatin every 3 week schedule in patients with metastatic or recurrent gastric cancer

15066

Background: S-1 plus cisplatin has been reported to be highly active in advanced gastric cancer (AGC). The objectives of this study were to define the maximal-tolerated dose (MTD) of S-1, given for 2 weeks separated by 1 week rest, with a fixed dose of cisplatin, and to determine the activity and safety of this combination regimen at the recommended dose (RD) when used as the first line treatment of AGC. Methods: Cisplatin was fixed at a dose of 60 mg/m2 on D1 and the starting dose of S-1 was 30 mg/m2 bid (level I) on D1 to D14 every 3 weeks. The dose of S-1 was increased by 5 mg/m2 bid up to 50 mg/m2 bid (level V) unless MTD was achieved. At every level, a cohort of 3 patients (pts), which could be expanded to 6 pts, was studied. Dose-limiting toxicities (DLTs) were assessed for the first 2 cycles. Results: From February 2004 to January 2006, 62 eligible pts were enrolled. In phase I (N=21), DLTs occurred at level V (S-1 50 mg/m2 bid), with 2 of 3 pts developing G3 diarrhea or febrile neutropenia. The RD was determined at level IV (45 mg/m2 bid) because only 1 DLT occurred out of 6 pts at this level. After the first 20 pts (series I) were enrolled in phase II, the protocol was amended; the S-1 dose was reduced down to 40 mg/m2 bid (level III, series II, N=23) because of poor bone marrow recovery and resultant treatment delay. At the time of analysis, a total of 272 cycles of chemotherapy were administered. The median age was 52 years (28–70) and ECOG PS was 0/1 in 98% of pts. The objective response was observed in 20(47%; 95% CI, 36–66%) of 43 pts. SD was achieved in 15 (35%) pts. With a median FU of 12.1 months (range 9.8–23.3) for all survivors, median PFS was 5.3 months (95% CI, 4.6–6.0 months) with a median OS of 10.0 months (95% CI, 5.1–14.8 months). G3–4 toxicities included neutropenia (33%), anemia (31%), anorexia (24%), and asthenia (14%); however severe febrile neutropenia, abdominal pain, and stomatitis were never observed. Conclusions: The cisplatin plus S-1 regimen incorporating 2-weeks on and 1-week off is highly active against gastric adenocarcinoma with favorable toxicitiy profiles in Korean patients.

No significant financial relationships to disclose.

Alteration of the substrate specificity of Thermus caldophilus ADP-glucose pyrophosphorylase by random mutagenesis through error-prone polymerase chain reaction

Expanding the scope of stereoselectivity is of current interest in enzyme catalysis. In this study, using error-prone polymerase chain reaction (PCR), a thermostable adenosine diphosphate (ADP)-glucose pyrophosphorylase (AGPase) from Thermus caldophilus GK-24 has been altered to improve its catalytic activity toward enatiomeric substrates including [glucose-1-phosphate (G-1-P) + uridine triphosphate (UTP)] and [N-acetylglucosamine-1-phosphate (GlcNAc) + UTP] to produce uridine diphosphate (UDP)-glucose and UDP-N-acetylglucosamine, respectively. To elucidate the amino acids responsible for catalytic activity, screening for UDP-glucose pyrophosphorylase (UGPase) and UDP-N-acetylglucosamine pyrophosphorylase (UNGPase) activities was carried out. Among 656 colonies, two colonies showed UGPase activities and three colonies for UNGPase activities. DNA sequence analyses and enzyme assays showed that two mutant clones (H145G) specifically have an UGPase activity, indicating that the changed glycine residue from histidine has the base specificity for UTP. Also, three double mutants (H145G/A325V) showed a UNGPase, and A325 was associated with sugar binding, conferring the specificity for the sugar substrates and V325 of the mutant appears to be indirectly involved in the binding of the N-acetylamine group of N-acetylglucosmine-1-phosphate.

Neoadjuvant weekly paclitaxel/cisplatin chemotherapy (WTP) with concurrent thoracic chemoradiation followed by surgical resection for stage IIIA (pN2) non-small cell lung cancer (NCLC): Phase II study

17036

Background: To investigate the role of weekly chemotherapy with paclitaxel/cisplatin and concurrent thoracic radiation (RT) as neoadjuvant therapy before surgical resection for patients with N2-IIIA NSCLC. Methods: Patients with pathologically proven N2 (pN2) and operable stage IIIA NSCLC were eligible. Six weekly chemotherapy with paclitaxel (50 mg/m2)/cisplatin (20 mg/m2) was given with concurrent thoracic RT (1.8 Gy/fraction once a day, 45 Gy) during 5 weeks. Chest CT, whole body PET were checked before and 3 weeks after chemoradiation. For the patients without clearing pN2 nodes or with pT3 after surgical resection, boost RT (20 Gy) was given. Results: From Jan. 2002 to Nov. 2005, 38 patients were enrolled. Median follow-up time was 20 months: gender (male: female, 30:8,), age (median 56, 42–67). Of them, 31 patients underwent surgical resection. Three patients showed brain metastasis during chmoradiation. Two patients refused surgical resection after chemoradiation. One patient showed severe radiation pneumonitis and was not fit for the operation. One patient showed lung to lung metastases before surgical resection. Of the 31 patients who underwent surgical resection, 14 (45.2%) showed pN0–1, and 7 (22.6%) showed pathologic complete remission (CR). Three year overall survival rate of all patients was 37.7% (median 35.9 months) and 3 year progression free survival was 34.2% (median 18 months). In univariate analysis, clearing N2 node and pathologic CR after surgery were the factors that could predict long-term survival. And the 2nd PET after chemoradiaiton could not expect clearing N2 nodes after surgical resection: sensitivity 44%, specificity 46%. As toxicities of WTP, hypersensivity reaction to paclitaxel and pneumonia with neutropenia were noted in 1 patient each. Severe radiation pneumonits was noted in 4 (of them 3 were given 65 Gy). Conclusions: WTP followed by surgical resection for N2-stage IIIA NSCLC was feasible. Clearing N2 nodes or pathologic CR after surgical resection were the factors of long-term survival. The usefulness of 2nd PET to expect the clearing N2 nodes was not adequate.

No significant financial relationships to disclose.

[18F]fluorothymidine (FLT) PET after 3 days of gefitinib treatment and tumor response in non-small cell lung cancer (NSCLC)

13031

Background: FLT has been developed as a PET tracer for imaging tumor proliferation. We evaluated whether FLT-PET could predict tumor response only after 3 days of gefitinib treatment. Methods: Nonsmokers with adenocarcinoma of the lung were eligible for this study. FLT-PET was performed at 1 day before and 3 days after the start of gefitinib (250 mg/d) therapy. The maximum standardized uptake value (SUVmax) of the main lung mass was measured, and changes in tumor SUVmax were calculated. After 6 weeks of therapy, response was assessed by chest CT according to WHO criteria. The cutoff value predicting subsequent CT response was obtained by receiver operating characteristic curve analysis. Results: Between Jun. 2005 and Nov. 2005, 22 patients were enrolled. CT response was partial response in 12 (54%), stable disease in 5 (23%), and progressive disease in 5 (23%). As early as 3 days after the initiation of therapy, significant difference in % changes of tumor SUVmax on FLT-PET was observed between responders and nonresponders (−32% v −2.3%, P = .002) ( Table ). When a reduction of tumor SUVmax ≥ 20% was used as a cutoff value for FLT-PET response, CT response could be predicted with positive and negative predictive values of 100% and 83%, respectively. Time to progression was significantly longer in FLT-PET responders than nonresponders (median 5.1 v 1.4 months, P = .011). Conclusions: Using FLT-PET obtained on days 0 and 3 of gefitinib therapy, the response could be early predicted in patients with NSCLC.

[Table: see text]

No significant financial relationships to disclose.

Ganglioside GM3 is involved in neuronal cell death

Gangliosides abundant in the nervous system have been implicated in a broad range of biological functions, including the regulation of cell proliferation and death. Glutamate-induced cell death, which is accompanied by an accumulation of reactive oxygen species (ROS), is a major contributor to pathological cell death within the nervous system. However, the mechanism underlying this neuronal cell death has not been fully elucidated. In this study, we report that ganglioside GM3 is involved in neuronal cell death. GM3 was up-regulated in the mouse hippocampal cell line HT22 death caused by glutamate. Increment in GM3 levels by both the exogenous addition of GM3 and the overexpression of the GM3 synthase gene induced neuronal cell death. Overexpression of GM3 synthase by microinjecting mRNA into zebrafish embryos resulted in neuronal cell death in the central nervous system (CNS). Conversely, RNA interference-mediated silencing of GM3 synthase rescued glutamate-induced neuronal death, as evidenced by the inhibition of massive ROS production and intracellular calcium ion influx. 12-lipoxygenase (12-lipoxygenase) (12-LOX) was recruited to glycosphingolipid-enriched microdomains (GEM) in a GM3-dependent manner during oxidative glutamate toxicity. Our findings suggest that GM3 acts as not only a mediator of oxidative HT22 death by glutamate but also a modulator of in vivo neuronal cell death.