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.

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.

Correction: Migrations of young spotted seals (Phoca largha) from Peter the Great Bay, Sea of Japan/East Sea, and the pattern of their use of seasonal habitats

[This corrects the article DOI: 10.1371/journal.pone.0244232.].

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.

Migrations of young spotted seals (Phoca largha) from Peter the Great Bay, Sea of Japan/East Sea, and the pattern of their use of seasonal habitats

We studied the migrations of young spotted seals during their annual cycle. In May 2017, we attached satellite tags (SPOT-293A) to three individuals (two underyearlings and one yearling) captured at their breeding ground in Peter the Great Bay, western Sea of Japan/East Sea. The operational time of the installed tags ranged from 207 to 333 days; a total of 27195 locations were uploaded. All three seals migrated east and further north along the coast of the mainland. The average daily migration speed of the seals ranged between 70 and 135 km/day. The yearling moved faster than the underyearlings. During early August, they arrived at their summer habitats, which were located in the northern part of the Tatar Strait (Sea of Japan/East Sea) for the underyearling seals and in Aniva Bay (Sea of Okhotsk) for the yearling seal. While moving from the place of tagging to the summer feeding grounds, the seals covered a distance of 2300 to 3100 km. From August to October, each seal permanently stayed within the same isolated area. The reverse migration of all three seals began in November. When the seals traveled south, they used the same routes by which they had moved north in the spring, but they moved at a faster speed. By December, two seals returned to their natal islands, where both stayed until their transmitters stopped sending signals (in March 2018).

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.

Deciphering the evolutionary signatures of pinnipeds using novel genome sequences: The first genomes of Phoca largha, Callorhinus ursinus, and Eumetopias jubatus

The pinnipeds, which comprise seals, sea lions, and walruses, are a remarkable group of marine animals with unique adaptations to semi-aquatic life. However, their genomes are poorly characterized. In this study, we sequenced and characterized the genomes of three pinnipeds (Phoca largha, Callorhinus ursinus, and Eumetopias jubatus), focusing on site-wise sequence changes. We detected rapidly evolving genes in pinniped lineages and substitutions unique to pinnipeds associated with amphibious sound perception. Phenotypic convergence-related sequence convergences are not common in marine mammals. For example, FASN, KCNA5, and IL17RA contain substitutions specific to pinnipeds, yet are potential candidates of phenotypic convergence (blubber, response to hypoxia, and immunity to pathogens) in all marine mammals. The outcomes of this study will provide insight into targets for future studies of convergent evolution or gene function.

Microbial community and functions associated with digestion of algal polysaccharides in the visceral tract of Haliotis discus hannai: Insights from metagenome and metatranscriptome analysis

Haliotis discus hannai, a species of Pacific abalone, is a highly valuable food source throughout Northeast Asia. As H. discus hannai primarily feed on brown algae and largely extract their energy from algal polysaccharides, understanding the mechanisms by which they digest algal polysaccharides is essential for elucidating their energy metabolism. Gut microbes, as well as the host animal, are involved in the process of polysaccharide degradation. To identify algal polysaccharide-digestion mechanisms and their origin, we analyzed the metagenome and metatranscriptome of abalone visceral extracts. Microbial communities were characterized using the 16S rRNA gene sequences in the metagenome and our results differed significantly from those of previous studies using traditional microbiological methods such as bacterial cultivation and cloning. A greater diversity of bacterial taxa was identified here than was previously identified using cultivation methods. Furthermore, the most abundant bacterial taxa also differed from previous studies, which is not common when comparing the results of bacterial culturing with those of molecular methodologies. Based on the metatranscriptome, overall functions were identified and additional analyses were performed on the coding sequences of algal polysaccharide-digestive enzymes, including alginate lyase. Results of the transcriptomic analyses suggest that alginate lyase in the visceral extracts of H. discus hannai was produced by the host itself, not by visceral bacteria. This is the first next-generation sequencing study performed on abalone to characterize the visceral microbiota and the source of the ability to digest algal polysaccharides by analyzing the metagenome and metatranscriptome together.

Characterization of the complete mitochondrial genome and phylogenetic analysis of the common dolphin Delphinus delphis (Cetacea: Delphinidae)

We report the complete mitogenome of the common dolphin, Delphinus delphis. Overall structure of the 16,387 bp mitogenome was very similar to those of other delphinid species, including the ancient D. delphis individuals. Multigene phylogeny revealed that D. delphis was most closely related to Stenella coeruleoalba, and clustered well with other species within the subfamily Delphininae.

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.

Comparative genomic analysis of Lactobacillus plantarum GB-LP4 and identification of evolutionarily divergent genes in high-osmolarity environment

Lactobacillus plantarum is one of the widely-used probiotics and there have been a large number of advanced researches on the effectiveness of this species. However, the difference between previously reported plantarum strains, and the source of genomic variation among the strains were not clearly specified. In order to understand further on the molecular basis of L. plantarum on Korean traditional fermentation, we isolated the L. plantarum GB-LP4 from Korean fermented vegetable and conducted whole genome assembly. With comparative genomics approach, we identified the candidate genes that are expected to have undergone evolutionary acceleration. These genes have been reported to associate with the maintaining homeostasis, which are generally known to overcome instability in external environment including low pH or high osmotic pressure. Here, our results provide an evolutionary relationship between L. plantarum species and elucidate the candidate genes that play a pivotal role in evolutionary acceleration of GB-LP4 in high osmolarity environment. This study may provide guidance for further studies on L. plantarum.

Genomic insights into Photobacterium damselae subsp. damselae strain KC-Na-1, isolated from the finless porpoise (Neophocaena asiaeorientalis)

Photobacterium damselae subsp. damselae (PDD) is a marine bacterium that can infect a variety of marine animals and humans. Although this bacterium has been isolated from several stranded dolphins and whales, its pathogenic role in cetaceans is still unclear. In this study, we report the complete genome of PDD strain KC-Na-1 isolated from a finless porpoise (Neophocaena asiaeorientalis) rescued from the South Sea (Republic of Korea). The sequenced genome comprised two chromosomes and four plasmids. Among the recently identified major virulence factors in PDD, only phospholipase (plpV) was found in strain KC-Na-1. Interestingly, two genes homologous to Vibrio thermostable direct hemolysin (tdh) and its transcriptional regulator toxR, which are known virulence factors associated with Vibrio parahaemolyticus, were encoded on the plasmid pPDD-Na-1-3. Based on these results, strain KC-Na-1 may have potential pathogenicity in humans and other marine animals and also could act as a potential virulent strain. To the best of our knowledge, this is the first report of the complete genome sequence of P. damselae.

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.

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.

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.

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.

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.

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.

The role of amino acids in the regulation of hydrogen sulfide production during ultradian respiratory oscillation of Saccharomyces cerevisiae

We previously demonstrated that periodic H2S production during aerobic continuous culture of Saccharomyces cerevisiae resulted in ultradian respiratory oscillation, and that H2S production was dependent on the activity of sulfate uptake and the level of sulfite. To investigate the mechanism of regulation of the sulfate assimilation pathway and of respiratory oscillation, several amino acids were pulse-injected into cultures during respiratory oscillation. Injection of sulfur amino acids or their derivatives perturbed respiratory oscillation, with changes in the H2S production profile. Four major regulators of H2S production in the sulfate assimilation pathway and respiratory oscillation were identified: (1) O-acetylhomoserine, not O-acetylserine, as a sulfide acceptor, (2) homoserine/threonine as a regulator of O-acetylhomoserine supply, (3) methionine/S-adenosyl methionine as a negative regulator of sulfate assimilation, and (4) cysteine (or its derivatives) as an essential regulator. The results obtained after the addition of DL-propargylglycine (5 microM and 100 microM) and cystathionine (50 microM) suggested that the intracellular cysteine level and cystathionine gamma-lyase, rather than methionine/S-adenosylmethionine, play an essential role in the regulation of sulfate assimilation and respiratory oscillation. Based on these results and those of our previous reports, we propose that periodic depletion of cysteine (or its derivatives), which is involved in the detoxification of toxic materials originating from respiration, causes periodic H2S production.

Mathematical analysis of a mechanism for autonomous metabolic oscillations in continuous culture of Saccharomyces cerevisiae

Autonomous metabolic oscillations were observed in aerobic continuous culture of Saccharomyces cerevisiae. Experimental investigation of the underlying mechanism revealed that several pathways and regulatory couplings are involved. Here a hypothetical mechanism including the sulfate assimilation pathway, ethanol degradation and respiration is transformed into a mathematical model. Simulations confirm the ability of the model to produce limit cycle oscillations which reproduce most of the characteristic features of the system.

Photopolymerization of liquid carbon disulfide produces nanoscale polythiene films

Broad band solar or 300--400 nm irradiation (Hg--Xe arc source) of liquid-phase carbon disulfide produces a new carbon--sulfur polymer with the approximate (n = 1.04--1.05) stoichiometry (CS(n))(x). The polymer, from here on called (CS)(x), forms as a approximately 200 nm thick transparent golden membrane as measured by SEM and AFM techniques. IR spectra for this polymer show some similarities with those obtained for the gas-phase photopolymerized (CS(2))(x) and the high-pressure-phase polymer of CS(2), called Bridgman's Black. The observed FT-IR absorptions of (CS)(x) include prominent features at 1431 (s, br), 1298 (m), 1250 (ms), and 1070 cm(-1) (m). In contrast to previous proposals for (CS(2))(x), (13)C labeling and model compound studies of alpha-(C(3)S(5))R(2) and beta-(C(3)S(5))R(2) (R = methyl or benzoyl) suggest that the absorption at 1431 cm(-1) and those at 1298 and 1250 cm(-1) are indicative of carbon--carbon double bonds and carbon--carbon single bonds, respectively. The molecular structure of alpha-(C(3)S(5))(C(O)C(6)H(5))(2), determined at -84 degrees C, belongs to space group P1, with a = 7.486(5) A, b = 13.335(11) A, c = 17.830(13) A, alpha = 105.60(6) degrees, beta = 95.32(6) degrees, gamma = 90.46(6) degrees, Z = 4, V = 1706(2) A(3), R = 0.0785, and R(w) = 0.2323. With use of electron and chemical ionization mass spectrometry, C(4)S(6) and C(6)S(7) were identified as the dominant soluble molecular side-products derived from a putative ethylenedithione (S==C==C==S) precursor. Atomic force microscopy (AFM) provided surface topology information for the thin film (CS)(x) and revealed features that suggested the bulk material is formed from small polymer spheres 20--50 nm in size. Both (CS(2))(x) and (CS)(x) are extensively cross-linked through disulfide linkages and both materials show strong EPR resonances (g > 2.006) indicative of sulfur-centered radicals from incomplete cross-linking. A polymerization mechanism based on the intermediacy of S(2)C=CS(2) is proposed.

Ultradian metabolic oscillation of Saccharomyces cerevisiae during aerobic continuous culture: hydrogen sulphide, a population synchronizer, is produced by sulphite reductase

We have reported that the consecutive cyclic production of H(2)S resulted in population synchrony of ultradian metabolic oscillation (Sohn et al., 2000). In order to understand the origin of H(2)S and its nature of periodic production, changes of sulphur compounds concentration and responsible enzymes were investigated. The concentrations of extracellular sulphate, intracellular glutathione and cysteine oscillated during metabolic oscillation but only the oscillation of sulphate concentration was out of phase with H(2)S production. The sulphate concentration in culture directly affected the amplitude and the period of metabolic oscillation: (a) the period of metabolic oscillation shortened from 50 min to 30 min when sulphate concentration in the medium was reduced from 46 mM to 2.5 mM; (b) the metabolic oscillation disappeared under sulphate-depletion conditions and arose again by the addition of sulphate. Pulse injection of sulphite (10 microM) perturbed metabolic oscillation with a burst production of H(2)S, while thiosulphate (up to 500 microM) was without apparent effect. Furthermore, addition of S-adenosyl methionine (100 microM) or azoxybacilin (3 mg/kg) decreased H(2)S production with perturbation of metabolic oscillation. The results presented here suggest that H(2)S, a population synchronizer, is produced by sulphite reductase in the sulphate assimilation pathway, and dynamic regulation of sulphate uptake plays an important role in ultradian metabolic oscillation.