Clinicopathologic differences of gastric neoplasms between Helicobacter pylori-infected and -naïve patients: a multicenter retrospective analysis.

BACKGROUND: The incidence of gastric neoplasms in Helicobacter pylori (Hp)-naïve patients has recently increased due to a remarkable decrease in the Hp-infected population in Japan. We investigated the clinicopathologic differences between Hp-infected gastric neoplasms (HpIGNs) and Hp-naïve gastric neoplasms (HpNGNs) that have not been fully elucidated so far. METHODS: This retrospective multicenter study investigated 966 consecutive patients with 1131 gastric dysplasia or cancers who underwent endoscopic or surgical treatment for the recent decade. Clinicopathologic features were compared between HpIGN and HpNGN cases. RESULTS: One thousand and sixty-eight HpIGNs in 916 patients included 877 differentiated types and 191 undifferentiated types. Sixty-three HpNGNs in 50 patients included 57 differentiated types (35 foveolar types, 15 intestinal types, 6 fundic-gland types, and 1 other differentiated type) and 6 undifferentiated types. HpNGNs occurred in younger (59.5 vs. 71.8 years, p < 0.05) and female patients (40.0% vs. 26.5%, p < 0.05), were found more frequently in the proximal compartment (p < 0.05), and had smaller size (median 4.0 vs. 20.0 mm, p < 0.05). Histologically, HpNGNs and HpIGNs both primarily consisted of differentiated type (90.5% vs. 82.1%, p = 0.089) and HpNGNs showed lower prevalence of invasive cancer (11.1% vs. 37.6%, p < 0.05) and lymphovascular invasion (1.6% vs. 31.6%, p < 0.05). Nearly all HpNGNs (62/63, 98.4%) were diagnosed in early pathological stage, while 16.1% (172/1068) of HpIGNs were diagnosed in advanced stage (p < 0.05). CONCLUSIONS: HpNGNs is recently on the increase but shows lower malignant nature regardless of histologic type than HpIGN. Endoscopic gastric cancer screening will be reviewed via cost effectiveness for Hp-naïve individuals in future.

Association of lysophosphatidic acid molecules with liver fibrosis: different roles indicated.

Lysophosphatidic acid is composed of lysophosphatidic acid (LPA) molecules with varied chemical forms. The present cross-sectional study was conducted to investigate the associations of various LPA molecules with liver fibrosis. Forty-six patients affected by various types of liver disease who underwent an ultrasound-guided liver biopsy were recruited for this study. Liver fibrosis was evaluated using histological grading, as well as shear wave velocity (Vs) and serum level of type IV collagen 7S (T4c7s). Serum levels of LPA molecules were determined using liquid-chromatography tandem mass-spectrometry (LC-MSMS). Total LPA showed a significant positive association with fibrosis severity evaluated based on histological grading, Vs, and T4c7s used as parameters, following adjustment for other confounding factors, including disease type, age, gender, body mass index, and high-sensitivity C-reactive protein. This association was replicated when 16:0-LPA was substituted for total LPA. In contrast, when 20:4-LPA was substituted for total LPA, no significant association with liver fibrosis was observed. In conclusion, the degree of association varied among the different LPA molecule chemical forms, suggesting different pathophysiological roles of individual LPA molecules, although total LPA concentration was shown to be associated with liver fibrosis.

Endoscopic differential diagnosis between foveolar-type gastric adenoma and gastric hyperplastic polyps in Helicobacter pylori-naïve patients.

BACKGROUND: Foveolar-type gastric adenoma (FGA) occurs in Helicobacter pylori (Hp)-naïve individuals and morphologically mimics Hp-naïve gastric hyperplastic polyp (HpN-GHP). FGA is often difficult to distinguish from HpN-GHP even by biopsy, due to its low-grade histologic atypia. We conducted a retrospective study to create an endoscopic diagnostic index. METHODS: We analyzed 51 FGAs in 41 patients and 36 HpN-GHPs in 24 patients. All lesions were photographed by white-light endoscopy (WLE) and narrow-band imaging with magnification endoscopy (NBIME). Three experts and three non-experts reviewed the WLE and WLE+NBIME images to assess six items for lesion diagnosis. We analyzed correlations between the diagnostic items and histologic features and compared the diagnostic accuracy between modalities. We created a composite diagnostic index and calculated its accuracy and consistency. RESULTS: FGAs more frequently showed the following features vs. HpN-GHPs: bright-red color (94.1% vs. 44.4%), peripheral hyperplasia (58.8% vs. 8.3%), papillary/gyrus-like microstructure (96.1% vs. 33.3%), visible capillaries (70.6% vs. 38.9%), and demarcation line (98.0% vs. 41.7%) (P < 0.05). White-zone thickening was seen only in HpN-GHPs (52.8%). Diagnostic accuracy (mean, WLE vs. WLE+NBIME) was 90.8 ± 1.1% vs. 93.5 ± 2.4% (P = 0.15) for experts and 88.5 ± 3.0% vs. 86.6 ± 3.5% (P = 0.51) for non-experts. When satisfying the four criteria (bright-red color, papillary/gyrus-like microstructure, demarcation line, and absent white-zone thickening), sensitivity and specificity for FGA were 90.2% and 94.4%, respectively, with a kappa value of ≥ 0.6 for interobserver diagnostic agreement. CONCLUSIONS: Composite diagnostic index contributes to the reproducible, accurate, preoperative differential diagnosis of FGA and HpN-GHP.

Low Fecal Calprotectin Predicts Histological Healing in Patients with Ulcerative Colitis with Endoscopic Remission and Leads to Prolonged Clinical Remission.

BACKGROUND: Consensus regarding the cutoff value of fecal calprotectin (FC) for predicting histological healing (HH) in ulcerative colitis (UC) is lacking. This study aimed to determine an optimal FC cutoff value for predicting HH in patients with UC with clinical and endoscopic remission. Furthermore, FC's predictability for prolonged clinical remission (CR) was investigated. METHODS: Patients with UC in clinical and endoscopic remission, defined as a partial Mayo score (PMS) ≤ 2 points and a Mayo endoscopic subscore 0-1, were prospectively enrolled. Biopsy samples were evaluated by Geboes score (GS), with HH defined as a GS < 2.0. Patients were followed for 2 years or until relapse, defined as a PMS > 2 or medication escalation. RESULTS: Seventy-six patients with UC were included. The median FC value in patients with HH (n = 40) was 56.2 µg/g, significantly lower than that in those with histological activity (118.1 µg/g; P < .01). The area under the curve (AUC) in a receiver operating characteristic (ROC) curve analysis to predict HH for FC was 0.71 (95% confidence interval [CI], 0.59-0.83), with an optimal cutoff value of 82.7 µg/g (73% sensitivity; 64% specificity; P < .01). Of 74 patients observed for 2 years, 54 (73%) had prolonged CR. In the ROC curve analysis, the AUC to predict prolonged CR for FC was 0.79 (95% CI, 0.68-0.90), equivalent to that for HH (0.73; 95% CI, 0.64-0.86; P = .40). The optimal FC cutoff value to predict prolonged CR was 84.6 µg/g (72% sensitivity; 85% specificity; P < .01). CONCLUSIONS: Fecal calprotectin < 82 µg/g predicts HH in patients with UC with clinical and endoscopic remission. Low FC leads to prolonged CR, equivalent to HH.

Fecal calprotectin (FC) levels < 82 µg/g predict histological healing in ulcerative colitis patients with clinical and endoscopic remission. Low FC leads to prolonged clinical remission for up to 2 years in those with clinical and endoscopic remission, equivalent to histological healing.

Lipocalin 2, synthesized using a cell-free protein synthesis system and encapsulated into liposomes, inhibits the adhesion of Porphyromonas gingivalis to human oral epithelial cells.

BACKGROUND AND OBJECTIVE: Lipocalin 2 (LCN2), a glycoprotein expressed in epithelial cells and leukocytes, has an antibacterial effect and plays a role in innate immunity. The delivery of LCN2 encapsulated in liposomes to oral epithelium may be useful to prevent oral infectious diseases. This study aimed to investigate the inhibitory effect of LCN2, artificially synthesized using a cell-free protein synthesis (CFPS) system, on the adhesion of Porphyromonas gingivalis to oral epithelial cells in order to approach oral healthcare using LCN2. METHODS: LCN 2 was synthesized using a CFPS system and assayed by Western blotting, mass spectrometry and enzyme-linked immunosorbent assay (ELISA). The bilayer liposomes were prepared by the spontaneous transfer method using 1,2-dioleoyl-sn-glycero-3 phosphocholine (DOPC), 3-sn-phosphatidylcholine from Egg Yolk (Egg-PC), and 1,2-dioleoyl-sn-glycero-3 phosphoethanolamine (DOPE). The cellular and medium fractions derived from the culture of oral epithelial cells with liposome-encapsulated LCN2 were assayed by Western blotting and ELISA. The effect of the synthesized LCN2 on adhesion of the labeled P. gingivalis to oral epithelial cells was investigated as an evaluation of its antibacterial activity. RESULTS: The synthesized LCN2 protein was identified by Western blotting; its amino acid sequence was similar to that of recombinant LCN2 protein. The additions of DOPE and octa-arginine in the outer lipid-layer components of liposome significantly increased the delivery of liposomes to epithelial cells. When oral epithelial cells were cultured with the synthesized and liposome-encapsulated LCN2, LCN2 was identified in the cellular and medium fractions by Western blotting and its concentration in the cellular fraction from the culture with the synthesized LCN2 was significantly higher than that of a template DNA-free protein. The synthesized LCN2 and liposome-encapsulated LCN2 significantly inhibited the adhesion of P. gingivalis to oral epithelial cells compared with template DNA-free protein. CONCLUSION: LCN2 was artificially synthesized by a CFPS system, encapsulated in liposomes, and delivered to oral epithelial cells, and demonstrated an antibacterial action against P. gingivalis. This approach may become a useful model for oral healthcare.

Immune checkpoint inhibitor (ICI)-induced hepatitis diagnosed by liver biopsy followed by ICI-free chemotherapy leading to therapeutic effect: A case of lung cancer treatment.

In recent years, the combination of platinum-based chemotherapy and immune checkpoint inhibitors (ICIs) has become the standard treatment for patients with lung cancer. Hepatitis is one of the common toxicities following ICI/chemotherapy. When drug-induced hepatitis occurs, the suspected drug must be discontinued. Since it may be difficult to determine the exact drug causing the hepatitis, liver biopsy may help identify this. We report the case of a patient diagnosed with immune-related adverse event hepatitis from liver biopsy and clinical course. A 45-year-old man with lung adenocarcinoma (stage IV, cT4N3M1c) negative for driver gene mutation was treated with carboplatin (CBDCA), pemetrexed (PEM), and pembrolizumab. Elevated blood aspartate aminotransferase and alanine aminotransferase levels after chemotherapy indicated hepatitis induced by cytotoxic anticancer agents and ICIs. As autoimmune hepatitis was also suspected, liver biopsy was performed and the findings suggested ICI-induced hepatitis. Pembrolizumab was discontinued and CBDCA/PEM was resumed, following which, the primary lesion shrank. When drug-induced hepatitis is suspected, clinicians should actively perform liver biopsy to confirm the diagnosis, so that appropriate therapeutic regimen can be administered.

Immune checkpoint inhibitor (ICI)-induced hepatitis diagnosed by liver biopsy followed by ICI-free chemotherapy leading to therapeutic effect: A case of lung cancer treatment.

In recent years, the combination of platinum-based chemotherapy and immune checkpoint inhibitors (ICIs) has become the standard treatment for patients with lung cancer. Hepatitis is one of the common toxicities following ICI/chemotherapy. When drug-induced hepatitis occurs, the suspected drug must be discontinued. Since it may be difficult to determine the exact drug causing the hepatitis, liver biopsy may help identify this. We report the case of a patient diagnosed with immune-related adverse event hepatitis from liver biopsy and clinical course. A 45-year-old man with lung adenocarcinoma (stage IV, cT4N3M1c) negative for driver gene mutation was treated with carboplatin (CBDCA), pemetrexed (PEM), and pembrolizumab. Elevated blood aspartate aminotransferase and alanine aminotransferase levels after chemotherapy indicated hepatitis induced by cytotoxic anticancer agents and ICIs. As autoimmune hepatitis was also suspected, liver biopsy was performed and the findings suggested ICI-induced hepatitis. Pembrolizumab was discontinued and CBDCA/PEM was resumed, following which, the primary lesion shrank. When drug-induced hepatitis is suspected, clinicians should actively perform liver biopsy to confirm the diagnosis, so that appropriate therapeutic regimen can be administered.

Combinational elastography for assessment of liver fibrosis in patients with liver injury.

OBJECTIVE: We investigated the utility of combinational elastography with point shear wave elastography (pSWE) and real-time tissue elastography (RTE) for evaluating liver fibrosis in patients with liver injury. METHODS: In this prospective single-institution study, patients scheduled for a liver biopsy to determine the presence of liver disease were enrolled. Liver fibrosis in each patient was evaluated using both shear wave velocity (Vs) shown by pSWE and the liver fibrosis index (LFI) shown by RTE, while a liver biopsy sample was obtained from the same area that was subjected to an elastography examination. Results of the latter were compared with those obtained in a histological examination. RESULTS: Multivariate analysis showed that Vs and LFI were significantly correlated with the liver fibrosis stage in all of the enrolled patients. Sub-analysis findings compared patients with and without non-alcoholic fatty liver disease (NAFLD) and demonstrated that Vs was significantly correlated with the liver fibrosis stage in both groups, whereas LFI was correlated with that only in the non-NAFLD patients. However, a multivariate analysis demonstrated a significant correlation between steatosis grade and LFI in the NAFLD patients. CONCLUSIONS: RTE is less useful than pSWE for assessing liver fibrosis in patients with NAFLD.

KLF4 Mutation Shapes Pathologic Characteristics of Foveolar-Type Gastric Adenoma in Helicobacter pylori-Naive Patients.

Along with a recent remarkable decrease in Helicobacter pylori-infected individuals, reports of gastric neoplasms such as sporadic foveolar-type gastric adenoma (FGA) in H. pylori-naive patients have been increasing. This tumor, with its raspberry-like appearance, is common in H. pylori-naive gastric mucosa. The current study investigated the genomic features of sporadic FGA. Fresh-frozen sporadic FGA tissue samples from H. pylori-naive patients were subjected to whole genome analysis using a next-generation sequencer. Proliferation ability and apoptotic profiles of human gastric epithelial cells, along with plasmid transfection of candidate variants, were examined. A mean of 6.65 × 108 total reads were obtained for each sample. Common genetic abnormalities in well-known proliferation driver genes of conventional gastric dysplasia/cancer were not found. However, a common single-nucleotide variation (SNV) was noted within the DNA-binding domain of the tumor suppressor gene KLF4. This novel SNV was located in the zinc finger 2 region. Additional experiments showed that it significantly suppressed proliferation of gastric epithelial cells compared with wild-type KLF4 plasmid-transfected cells, although suppression was reduced in early apoptotic phase-related genes. A novel SNV in the KLF4 zinc finger 2 region was commonly found in sporadic FGA tissue samples, which may explain the slow-growing properties of this neoplasm.

Oxaliplatin-related Portal Hypertension Complicated with Esophageal Varices and Refractory Massive Ascites.

Oxaliplatin, widely used as a chemotherapy drug for colorectal cancer, is known to cause various adverse reactions. In particular, special attention for the development of portal hypertension associated with porto-sinusoidal vascular disease is necessary, as it is a serious adverse life-threating reaction, although rare. We herein report a case of oxaliplatin-related portal hypertension that developed several years after oxaliplatin administration and led to esophageal varices and refractory massive ascites. Clinical physicians should be aware of the possibility of oxaliplatin-induced portal hypertension and its possible development over a long period after discontinuation of the drug.

Low potency of fecal immunological surveillance testing soon after negative colonoscopy or resection of low-risk adenoma in average-risk patients.

BACKGROUND: Postcolonoscopy surveillance colonoscopy based on positive fecal occult blood testing (FOBT) is often performed, although its long-term efficacy has not been established. The aim of this study was to clarify the low potency of FOBT surveillance at short intervals after colonoscopy. METHODS: Colonoscopy was performed in 1308 average-risk patients, based on positive results of immunological FOBT [fecal immunological test (FIT)]. Patients were stratified according to the length of time since their last colonoscopy and their colonoscopy results [no adenoma or 1-2 small (<10 mm) adenomas]. Tumor detection rates were determined. RESULTS: The baseline patients characteristics did not differ between the groups. The advanced lesion detection rate (ALDR) among the patients who had never undergone a colonoscopy was 21.9% [95% confidence interval (CI), 19.1-25.0%]. Among the patients who had no adenoma detected in the previous colonoscopy within the past 5 years, the past 5-10 years and over 10 years, the ALDRs were 2.5% (95% CI, 1.0-5.5%), 4.1% (95% CI, 1.5-9.4%) and 9.3% (95% CI, 3.1-22.2%), respectively. Among the patients who had 1-2 small adenomas, the ALDRs were 7.4% (95% CI, 3.4-14.8%), 12.1% (95% CI, 4.2-27.9%) and 27.8% (95% CI, 12.2-51.2%), respectively. Invasive cancer was not observed in any patients within 5 years since the prior colonoscopy. CONCLUSION: In average-risk patients whose prior colonoscopy detected no adenomas or low-risk adenomas, postcolonoscopy surveillance by FIT has a low positive predictive value within a 5-year interval.

Application of Micropore Device for Accurate, Easy, and Rapid Discrimination of Saccharomyces pastorianus from Dekkera spp.

Traceability analysis, such as identification and discrimination of yeasts used for fermentation, is important for ensuring manufacturing efficiency and product safety during brewing. However, conventional methods based on morphological and physiological properties have disadvantages such as time consumption and low sensitivity. In this study, the resistive pulse method (RPM) was employed to discriminate between Saccharomyces pastorianus and Dekkera anomala and S. pastorianus and D. bruxellensis by measuring the ionic current response of cells flowing through a microsized pore. The height and shape of the pulse signal were used for the simultaneous measurement of the size, shape, and surface charge of individual cells. Accurate discrimination of S. pastorianus from Dekkera spp. was observed with a recall rate of 96.3 ± 0.8%. Furthermore, budding S. pastorianus was quantitatively detected by evaluating the shape of the waveform of the current ionic blockade. We showed a proof-of-concept demonstration of RPM for the detection of contamination of Dekkera spp. in S. pastorianus and for monitoring the fermentation of S. pastorianus through the quantitative detection of budding cells.

Primary Extragastrointestinal Stromal Tumor of Greater Omentum with Intraperitoneal Bleeding.

Gastrointestinal stromal tumors (GISTs) develop in the digestive tract, mainly in the stomach, small intestine, colon, or esophagus. However, primary tumors with the same pathologic features as GISTs have been reported to occur outside of the digestive tract and are called extragastrointestinal stromal tumor (EGIST). We herein report a rare case of EGIST arising from the greater omentum in a patient with abdominal pain caused by intraperitoneal bleeding from the tumor.

[Pyogenic granuloma in small intestine associated with Cowden's disease in a patient with gastrointestinal bleeding:a case report].

A 57-year-old female with a history of Cowden's disease was referred to our hospital because of black stool, loss of consciousness, and severe anemia. Upper and lower gastrointestinal endoscopy findings could not confirm the source of hemorrhage. Capsule endoscopy (CE) of the small intestine showed an active exudative hemorrhagic site near the ileum, although a definitive diagnosis was difficult. In a double balloon enteroscopy examination, it was difficult to observe the entire small intestine due to adhesions and the responsible lesion could not be confirmed, even when ink spots were applied to the deepest observation points through the mouth and anus. Hemostasis spontaneously occurred, and then anemia occurred again approximately 1 month later and a second CE examination was performed including passage of an ink stick through the oral side, which revealed an exudative elevated polyp with erosion and a white moss appearance in the ileum. Partial ileal resection was performed and pyogenic granuloma of the small intestine was the diagnosis. We report here a case of pyogenic granuloma of the small intestine associated with Cowden's disease.

Effect of Electrolyte Concentration on Cell Sensing by Measuring Ionic Current Waveform through Micropores.

Immunostaining has been widely used in cancer prognosis for the quantitative detection of cancer cells present in the bloodstream. However, conventional detection methods based on the target membrane protein expression exhibit the risk of missing cancer cells owing to variable protein expressions. In this study, the resistive pulse method (RPM) was employed to discriminate between cultured cancer cells (NCI-H1650) and T lymphoblastoid leukemia cells (CCRF-CEM) by measuring the ionic current response of cells flowing through a micro-space. The height and shape of a pulse signal were used for the simultaneous measurement of size, deformability, and surface charge of individual cells. An accurate discrimination of cancer cells could not be obtained using 1.0 × phosphate-buffered saline (PBS) as an electrolyte solution to compare the size measurements by a microscopic observation. However, an accurate discrimination of cancer cells with a discrimination error rate of 4.5 ± 0.5% was achieved using 0.5 × PBS containing 2.77% glucose as the electrolyte solution. The potential application of RPM for the accurate discrimination of cancer cells from leukocytes was demonstrated through the measurement of the individual cell size, deformability, and surface charge in a solution with a low electrolyte concentration.

Comparison of dapagliflozin and teneligliptin in nonalcoholic fatty liver disease patients without type 2 diabetes mellitus: a prospective randomized study.

There are no reports regarding the efficacy of sodium-glucose cotransporter 2 inhibitor (SGLT2i) and dipeptidyl peptidase 4 inhibitor (DPP4i) administrations in nonalcoholic fatty liver disease (NAFLD) patients without type 2 diabetes mellitus. The purpose of this study was to evaluate the efficacy of those drugs in such patients. NAFLD patients without type 2 diabetes mellitus were enrolled in this single center double-blind randomized prospective study, and allocated to receive either dapagliflozin (SGLT2i) or teneligliptin (DPP4i) for 12 weeks. Laboratory variables and body compositions were assessed at the baseline and end of treatment. The primary endpoint was alanine aminotransferase (ALT) reduction level at the end of treatment. Twenty-two eligible patients (dapagliflozin group, n = 12; teneligliptin group, n = 10) were analyzed. In both groups, the serum concentration of ALT was significantly decreased after treatment (p<0.05). Multiple regression analysis results showed that decreased body weight of patients with dapagliflozin administration was significantly related to changes in total body water and body fat mass. Administration of dapagliflozin or teneligliptin decreased the serum concentration of ALT in NAFLD patients without type 2 diabetes mellitus. With dapagliflozin, body weight decreased, which was related to changes in total body water and body fat mass (UMIN000027304).

Initial Computed Tomography Findings of Long and Distended Colon Are Risk Factors for the Recurrence of Sigmoid Volvulus.

BACKGROUND: Sigmoid volvulus is a common condition in elderly patients with elongated colons. Although endoscopic de-torsion is effective as the primary treatment of sigmoid volvulus, elective surgery is recommended because of the high risk of recurrence and high mortality rate. AIM: The aim of this study was to determine the risk factors for the recurrence of sigmoid volvulus. METHODS: Clinical records of patients treated at Shimane Prefectural Central Hospital were reviewed retrospectively. Among 41 sigmoid volvulus patients who were successfully treated by endoscopic de-torsion and followed up, 30 were observed over 1 year. Among the 30 patients, eight (26.7%) did not experience recurrence, while 22 (73.3%) did. Initial computed tomography (CT) findings indicating the sigmoid colon extending to the diaphragm or ventral to the liver were defined as "extension findings." Extension findings and sigmoid diameter were evaluated in relation to sigmoid volvulus recurrence. RESULTS: Extension findings were significantly more frequent in the recurrent group (77.3%) than in the nonrecurrent group (25.0%) (P = 0.009). Distended sigmoid colon diameter was significantly larger in the recurrent group (11.7 ± 3.8 cm) than in the nonrecurrent group (7.1 ± 1.1 cm) (P = 0.044). Receiver operating characteristic curve analysis demonstrated that the performance threshold was greater than 8.9 cm. Kaplan-Meier analysis showed the significantly high sigmoid volvulus recurrence rate in the patients with extension findings and a distended sigmoid colon greater than 8.9 cm. CONCLUSIONS: CT findings of a long and distended sigmoid colon in initial sigmoid volvulus are risk factors for the recurrence of sigmoid volvulus.

Ex vivo susceptibility of Plasmodium falciparum to antimalarial drugs in Northern Uganda.

In Uganda, artemether-lumefantrine was introduced as an artemisinin-based combination therapy (ACT) for malaria in 2006. We have previously reported a moderate decrease in ex vivo efficacy of lumefantrine in Northern Uganda, where we also detected ex vivo artemisinin-resistant Plasmodium falciparum. Therefore, it is necessary to search for candidate partner alternatives for ACT. Here, we investigated ex vivo susceptibility to four ACT partner drugs as well as quinine and chloroquine, in 321 cases between 2013 and 2018. Drug-resistant mutations in pfcrt and pfmdr1 were also determined. Ex vivo susceptibility to amodiaquine, quinine, and chloroquine was well preserved, whereas resistance to mefloquine was found in 45.8%. There were few cases of multi-drug resistance. Reduced sensitivity to mefloquine and lumefantrine was significantly associated with the pfcrt K76 wild-type allele, in contrast to the association between chloroquine resistance and the K76T allele. Pfmdr1 duplication was not detected in any of the cases. Amodiaquine, a widely used partner drug for ACT in African countries, may be the first promising alternative in case lumefantrine resistance emerges. Therapeutic use of mefloquine may not be recommended in this area. This study also emphasizes the need for sustained monitoring of antimalarial susceptibility in Northern Uganda to develop proper treatment strategies.

Highly Sensitive and Rapid Quantitative Detection of Plasmodium falciparum Using an Image Cytometer.

The gold standard for malaria diagnosis is microscopic examination of blood films by expert microscopists. It is important to detect submicroscopic and asymptomatic Plasmodium infections in people, therefore the development of highly sensitive devices for diagnosing malaria is required. In the present study, we investigated whether an imaging cytometer was useful for the highly sensitive quantitative detection of parasites. Whole blood samples were prepared from uninfected individuals spiked with Plasmodium falciparum-infected erythrocytes. Thereafter, erythrocytes were purified using a push column comprising of a syringe filter unit with SiO2-nanofiber filters. After adding the erythrocytes, stained with nuclear stain, to a six-well plate, quantitative detection of the parasites was performed using an image cytometer, CQ1. Imaging of 2.6 × 106 erythrocytes was completed in 3 min, and the limit of detection indicated parasitemia of 0.00010% (≈5 parasites/µL of blood). In addition to rapid, highly sensitive, and quantitative detection, the ease of application and economic costs, image cytometry could be efficiently applied to diagnose submicroscopic parasites in infected people from endemic countries.

Protective effects of Olyset® Net on Plasmodium falciparum infection after three years of distribution in western Kenya.

BACKGROUND: Several types of insecticides, treating technologies and materials are available for long-lasting insecticide-treated nets (LLINs). The variations may result in different efficacies against mosquitoes and correspondingly infection risks for the Plasmodium falciparum malaria parasite. This cross-sectional study investigated whether infection risk varied among children who slept under different LLIN brands in rural villages of western Kenya. METHODS: Children sleeping under various types of LLINs were tested for P. falciparum infection using a diagnostic polymerase chain reaction (PCR) assay. Data were collected for other potential factors associated with infection risk: sleeping location (with bed/without bed), number of persons sharing the same net, dwelling wall material, gap of eaves (open/close), proportional hole index, socio-economic status, and density of indoor resting anophelines. Bed-net efficacy against the Anopheles gambiae susceptible strain was estimated using the WHO cone test and the tunnel test. The residual insecticide content on nets was measured. RESULTS: Seven LLIN brands were identified, and deltamethrin-based DawaPlus® 2.0 was the most popular (48%) followed by permethrin-based Olyset® Net (28%). The former LLIN was distributed in the area about six months before the present study was conducted, and the latter net was distributed at least three years before. Of 254 children analysed, P. falciparum PCR-positive prevalence was 58% for DawaPlus® 2.0 users and 38% for Olyset® users. The multiple regression analysis revealed that the difference was statistically significant (adjusted OR: 0.67, 95% credible interval: 0.45-0.97), whereas the confounders were not statistically important. Among randomly selected net samples, all DawaPlus® 2.0 (n = 20) and 95% of Olyset® (n = 19) passed either the cone test or the tunnel test. CONCLUSIONS: Olyset® was more effective in reducing infection risk compared with DawaPlus® 2.0. Although the data from the present study were too limited to explain the mechanism clearly, the results suggest that the characteristics of the former brand are more suitable for the conditions, such as vector species composition, of the study area.