[What the practicing physician should know about loa filariasis].
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Africa↗
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IgG4 serology of loiasis in three villages in an endemic area of south-eastern Gabon.
Human filariasis due to Loa loa differs from other filariasis in that the majority of infected subjects are without circulating microfilariae (occult loiasis). In search for alternative diagnostic methods, which do not depend on circulating microfilariae or the (rather infrequent) eye-passage of adult worms, it was shown earlier that IgG4 antibodies directed against Loa loa adult worm antigen are apparently a good marker of occult loiasis and specific with regard to the sympatrically occurring Mansonella perstans. In this study we evaluated an IgG4 antibody-based ELISA using crude extract of Loa loa microfilariae (which is easier to obtain than adult worm) to estimate the prevalence of loiasis in 3 villages in South-East Gabon. Of 222 examined individuals (80 children < 16 years, 142 adults) 44 (20%) carried Loa loa microfilariae and 170 (77%) M. perstans. Using the mean OD-value + 1 standard deviation of 9 sera from patients solely infected with M. perstans (from the Gambia, where Loa loa is not endemic) as a cut-off, 35 of the 44 microfilaraemic Loa loa patients and 2 of the 9 Gambian controls were positive. This shows that our method had a sensitivity of 80% and a specificity of 78%. Among the remaining 178 subjects who had no microfilariae of Loa loa, as many as 97 (55%) had significant levels of specific IgG4 antibodies against Loa loa, suggesting that they carried occult loiasis. The mean IgG4 level in these putatively occult loiasis patients was slightly but significantly lower than in microfilaraemic subjects (P < 0.03). In conclusion, despite the limited sensitivity and specificity of our method, IgG4- ELISA at present is a very useful tool in estimating the real prevalence of loiasis in epidemiological surveys and at the individual level can confirm the diagnosis of L. loa amicrofilaraemic subjects with clinical signs suggesting loiasis.
Adolescent↗
[Secondary effects of the treatment of hypermicrofilaremic loiasis using ivermectin].
In the last ten years ivermectin appeared an efficient and safe alternative to diethylcarbamazine which is known to induce severe adverse reactions in loiasis, including encephalitis. After these results, large scale ivermectin treatments against onchocerciasis were carried out in Central Africa where loiasis is also endemic; and seven cases of severe reaction were reported in Cameroon since 1991, during these mass ivermectin treatments. In order to study adverse reactions in patients harbouring high load of Loa loa microfilariae (mf), we realized careful hospital based treatment in 112 patients with more than 3,000 mf/ml (ml) blood. Patients received once 200 micrograms ivermectin per kilogram at day 0 (D0). Clinical examination was made daily during the four following days (D1 to D4). Blood and urine samples were analysed before treatment and at D1 and D3. Lumbar puncture was made at D1 for 39 patients with more than 10,000 mf/ml; at D3 for the 49 following patients without consideration for the level of parasitaemia, and at D0 and D3 for ten voluntary patients. For analysis the patients were distributed in 3 groups according to initial parasitaemia: the first group included 50% out of the patients, those whose parasitaemia was fewer than 15,000 mf/ml blood; the second group included 25% patients whose parasitaemia was between 15,000 and 30,000 mf/ml; the third group included the last 25% patients whose parasitaemia was higher than 30,000 mf per ml blood. Adverse reactions were observed in 71% out of the patients. Symptoms described were fever, pruritus, headache, arthralgia. Most symptoms appeared 24 to 36 hours after treatment. Temperature increased significantly in group 3. Microfilaraemia decreased by 85% in the 3 groups during the 4 days following treatment. C-reactive-protein increased dramatically after treatment in all patients (p < 10(-4)). Some patients presented blood in urine in three groups but haematuria reached 35% of patients in group 3. Proteinuria is noted among 33% of all patients but 20% in group 1 and 2 versus 70% in group 3. Loa loa mf were observed in urine of half the patients, but in low amounts (< 10 mf per 50 ml urine). In cerebro-spinal fluid (CSF), some mf appeared at D1 or D3 in people heavily infected with Loa loa, reaching 80% of the patients of group 3. LP made at D0 in ten patients with parasitaemia higher than 30,000 mf/ml blood confirmed that CSF was naturally microfilaria free before treatment. One patient presented severe troubles with fever, asthenia and conscience troubles beginning at D3, reactive coma at D4, renal impairment with transitory anuria; progressive improvement in 2 weeks and complete recovery at D22; he presented 102 mf/ml CSF at D6. The study confirmed that ivermectin treatment is generally well tolerated. Among people with high Loa loa parasitaemia the symptoms after treatment are frequent but mild. However severe cases with conscience troubles are possible, and may occur in about 1% of subjects with more than 3,000 mf/ml blood. Severity of adverse reactions was linked to level of parasitaemia before treatment. The critical parasitaemia level which could lead to expect serious adverse effects seems to be 30,000 ml/ml blood. These informations should induce carefulness to carry out large scale treatments against filariosis in endemic areas of Loa loa.
Adult↗
Periodontal disease among the middle-aged Vietnamese population.
Information about periodontal disease patterns among the populations of developing countries is limited. These populations may illustrate the natural history of the disease owing to low or virtually no access to dental care, contributing to a more complete understanding of the disease process. The present study aimed to describe the patterns of periodontal loss of attachment (LOA) among representative middle-aged Vietnamese adults. A multi-stage, stratified random sampling technique was employed in two randomly selected provinces. The US NIDR protocol with two sites per tooth for the whole mouth, excluding third molars, was used to assess LOA. A total of 575 subjects aged 35-44 years were interviewed and periodontally examined (response 84.6%). Data were re-weighted to reflect the population of the two provinces. Oral hygiene status was poor with high accumulation of plaque and calculus. The prevalence, extent of sites with pockets (PD), recession (GR) and LOA exceeding various thresholds and the severity of LOA were calculated. Almost all subjects presented with at least one site with LOA > or = 2 mm but the higher levels of the disease were skewed. The extent of sites with GR, PD and LOA > or = 4mm was 1.35, 5.04 and 11.81 per cent respectively. More buccal sites had GR, while more mesial sites had PD and LOA. Severity score of LOA was 2.5 (SD: 0.7). LOA of 4+mm were observed more at maxillary molar buccal sites, followed by mandibular incisor mesial sites. LOA was prevalent among middle-aged Vietnamese adults. The loss of periodontal support was positively skewed and varied between teeth and sites.
Adult↗
Muscle lines-of-action affect predicted forces in optimization-based spine muscle modeling.
This study describes the effects of varied torso muscle geometries commonly assumed in optimization-based muscle force prediction models. Specifically, the sensitivity of predicted muscle and spinal forces to assumed muscle lines-of-action (LOA) is systematically examined. The practical significance of varied muscle LOAs is addressed by determining the relative precision needed for individual muscle LOAs and assessing which muscles are more critical to accurate prediction of spinal forces. To perform this analysis a nonlinear optimization model was used to generate muscle force predictions during combined frontal and sagittal plane moment loadings with an assumed erect posture. The LOAs of the erector spinae, rectus abdominus, internal and external oblique, and latissimus dorsi were systematically varied in the frontal and sagittal planes over an anatomically feasible range. The results indicated that moderate changes in the assumed LOA could substantially alter the magnitudes of predicted muscle and spinal forces. The estimated activity level of a muscle, as well as the predicted active/silent state could be affected by the LOA of that muscle and others. The patterns of predicted muscle activity, with respect to load orientation, underwent only minor alterations with changing LOA. The relative activation of several muscles, however, was dependent on LOA, and frequently led to variations in predicted spinal compression (> 100 N change) and shear forces (> 50 N change). This dependence of estimated spinal forces on assumed muscle geometry was most pronounced for the obliques and minimal for the more vertically oriented muscles and when loads were sagittally symmetric. This study suggests that muscle LOAs are critical inputs when interpreting absolute muscle and spinal force values predicted by models of physical exertions.
Algorithms↗
Periodontal attachment loss among adults aged 60+ in South Australia.
This study aimed to provide oral epidemiological data describing periodontal destruction among older adults in South Australia. A cross-sectional survey design was employed and periodontal assessments were made among 801 persons aged 6+ drawn at random from the non-institutionalized population. Measurements of pocket depth (PD) and gingival recession (GR) were made at three sites on all teeth and used to compute loss of attachment (LOA). An average of 17 teeth per person were measured. LOA of 4+ mm at one or more sites was observed among 89.1% of persons. A mean of 78.1% of sites per person had LOA of 2+ mm (extent) and the mean LOA at sites with LOA of 2+ mm was 3.09 mm (severity). Extent and severity were greater for males and for persons aged 80+ years. Extent was virtually identical for mesio-buccal and disto-lingual sites, while severity was virtually identical for mid-buccal and disto-lingual sites. Patterns of GR and PD varied according to the jaw and type of tooth. Maxillary first and second molars had the greatest mean LOA, and the majority of LOA in the maxilla was due to PD. In the mandible there was less variation in LOA among anterior and posterior teeth, and LOA tended to be more equally divided between GR and PD. Levels of periodontal destruction of South Australia were broadly similar to results from North American studies of older adults which have used full-mouth periodontal assessments.
Age Factors↗
Reproducibility of exhaled breath condensate pH in chronic obstructive pulmonary disease.
Increasingly, exhaled breath condensate (EBC) is being used to sample airway fluid from the lower respiratory tract. EBC pH may be a biomarker of airway inflammation in chronic obstructive pulmonary disease (COPD). In this study, the reproducibility of EBC pH in COPD was investigated. A total of 36 COPD patients and 12 healthy nonsmoking subjects participated in several investigations: duration of argon deaeration, within-sample variability, effect of freezing, leaving samples at room temperature, nose-peg use, within- (WD) and between-day (BD) variability. Analysis of repeated measurements was performed using the Bland-Altman method with limits of agreement (LOA; mean difference+/-2 SD). Wider LOA indicate greater variability. EBC pH became significantly higher with argon deaeration for < or =5 min. Variability during sample analysis was minimal; LOA of within-sample variability, freezing for 3 months and leaving at room temperature for 3 h were -0.29-0.45, -0.37-0.42 and -0.13-0.09, respectively. In contrast, variability due to nose-peg use (LOA -1.46-1.99), WD (LOA -1.50-2.48) and BD variability (LOA -2.52-3.02) were higher in COPD. In healthy nonsmoking subjects, nose-peg use (LOA -0.27-0.23), WD (LOA -0.33-0.40) and BD variability (LOA -0.46-0.44) were more reproducible. In conclusion, the variability of exhaled breath condensate pH in chronic obstructive pulmonary disease patients is mainly due to changes in airway pH over time, which are not seen in healthy nonsmoking subjects. Reasons for these fluctuations in exhaled breath condensate pH are unclear and require further investigation.
Adult↗
Hemoglobin oxygen saturation discrepancy using various methods in patients with sickle cell vaso-occlusive painful crisis.
OBJECTIVE: To evaluate agreement among various methods for measuring oxyhemoglobin (O2Hb) saturation in adult hypoxic patients with sickle cell disease (SCD) during painful vaso-occlusive crisis and to compare those results with a control group. PATIENTS AND METHODS: The hemoglobin oxygen saturation was determined simultaneously by pulse oximetry (SpO2), co-oximetry [SO2 (functional oxyhemoglobin saturation) and FO2Hb (oxyhemoglobin fraction)] and by calculation (SaO2) using a normal O2Hb dissociation curve in 18 adult patients with SCD during vaso-occlusive crisis and 12 non-SCD patients with various cardiopulmonary diagnoses. The method proposed by Bland and Altman was used to evaluate agreement of various methods in each of the two groups. RESULTS: Mean differences between various methods in patients with SCD were significantly larger than the control group. Limits of agreement (LOA) were also wider in the SCD group than in the control group. Mean bias between SpO2 and SO2, and SpO2 and FO2Hb in patients with SCD were -3.1 +/- 4.4 (LOA: -11.9 to 5.7) and 2 +/- 4.1 (LOA: -6.2 to 10.2) respectively, compared with -1.4 +/- 1.4 (LOA: -4.2 to 1.4) and 1.2 +/- 1.5 (LOA: -1.9 to 4.3) in the control group. A mean bias of -4.5 +/- 4 (LOA: -12.5 to 3.5) between SpO2 and SaO2 was noted in patients with SCD compared with -0.1 +/- 2.1 (LOA: -4.3 to 4.1) in the control group. The width of LOA for various methods in patients with SCD ranged from 9.8 to 17.6 compared with 1.3 to 8.4 in the control group. CONCLUSION: Patients with SCD during vaso-occlusive crisis have discrepancies in O2Hb saturation measurements by various methods. Abnormal pulse oximetry values in these patients should be interpreted cautiously and supplemented by arterial blood gas analysis and co-oximetry.
Adult↗
Homologs of the Brugia malayi diagnostic antigen BmR1 are present in other filarial parasites but induce different humoral immune responses.
BACKGROUND: The recombinant antigen BmR1 has been extensively employed in both ELISA and immunochromatographic rapid dipstick (Brugia Rapid) formats for the specific and sensitive detection of IgG4 antibodies against the lymphatic filarial parasites Brugia malayi and Brugia timori. In sera of individuals infected with Wuchereria bancrofti the IgG4 reactivity to BmR1 is variable, and cross-reactivity of sera from individuals infected with Onchocerca volvulus or Loa loa was observed only in single cases. In order to characterize the homologs of the BmR1 antigen in W. bancrofti (Wb-BmR1), O. volvulus (Ov-BmR1) and L. loa (Ll-BmR1) the cDNA sequences were identified, the protein expressed and the antibody reactivity of patients' sera was studied. METHODS: PCR methodology was used to identify the cDNA sequences from cDNA libraries and/or genomic DNA of W. bancrofti, O. volvulus and L. loa. The clones obtained were sequenced and compared to the cDNA sequence of BmR1. Ov-BmR1 and Ll-BmR1 were expressed in E. coli and tested using an IgG4-ELISA with 262 serum samples from individuals with or without B. malayi, W. bancrofti, O. volvulus and L. loa infections or various other parasitic infections. BmR1, Ov-BmR1 and Ll-BmR1 were also tested for reactivity with the other three IgG subclasses in patients' sera. RESULTS: Wb-BmR1 was found to be identical to BmR1. Ov-BmR1 and Ll-BmR1 were found to be identical to each other and share 99.7% homology with BmR1. The pattern of IgG4 recognition of all serum samples to BmR1, Ov-BmR1 and Ll-BmR1 were identical. This included weak IgG4 reactivities demonstrated by L. loa- and O. volvulus-infected patients tested with Ov-BmR1 and Ll-BmR1 (or BmR1). With respect to reactivity to other IgG subclasses, sera from O. volvulus- and L. loa-infected patients showed positive reactions (when tested with BmR1, Ov-BmR1 or Ll-BmR1 antigens) only with IgG1. No reactivity was observed with IgG2 or with IgG3. Similarly, ELISAs to detect reactivity to other anti-filarial IgG subclasses antibodies showed that sera from individuals infected with B. malayi or W. bancrofti (active infections as well as patients with chronic disease) were positive with BmR1 only for IgG1 and were negative when tested with IgG2 and with IgG3 subclasses. CONCLUSIONS: This study demonstrates that homologs of the BmR1 antigen are present in W. bancrofti, O. volvulus and L. loa and that these antigens are highly conserved. Recognition of this antigen by patients' sera is similar with regard to IgG1, IgG2 and IgG3, but different for IgG4 antibodies. We conclude that the BmR1 antigen is suitable for detection of IgG4 antibodies in brugian filariasis. However, its homologs are not suitable for IgG4-based diagnosis of other filarial infections.
Journal Article↗
Contrast-enhanced magnetic resonance imaging assessment of scar size in patients with chronic myocardial infarction.
BACKGROUND: In the assessment of myocardial infarction (MI) mass, contrast-enhanced magnetic resonance imaging (CE-MRI) is comparable to single-photon emission computed tomography (SPECT). The aim of the present study was to determine whether the MI area, as assessed at CE-MRI and SPECT, is comparable to mass evaluation. We also compared CE-MRI and SPECT estimates of the MI area with functional evaluations made at echocardiography and kinetic MRI (cine-MRI). METHODS: We used a 1.0 Tesla MRI scanner and an inversion-recovery turboFLASH sequence, a tomographic gamma-camera and second-harmonic ultrasound systems. Two blinded operators assessed the extent of scarring, expressed as a percentage of the whole left ventricle (LV), using a 16-segment model. We studied 55 consecutive patients with a clinically stable healed MI (50 Q wave, 5 non-Q wave). RESULTS: The scar mass was 19+/-23% of the LV at CE-MRI and 21+/-25% at SPECT; the scar area was 29+/-23% of the LV at CE-MRI, 41+/-28% at SPECT, 29+/-31% at cine-MRI, and 32+/-29% at echocardiography. The Bland-Altman bias between CE-MRI and SPECT mass estimations was -2% of the LV with a+/-23% limit of agreement (LOA), while the bias between the area assessments was -12% with a+/-42% LOA. Bias between CE-MRI and functional evaluation by cine-MRI and echocardiography was 0% with a+/-39% LOA and -3% with a+/-36% LOA respectively. Comparing SPECT with cine-MRI and echocardiography the bias was 12% with a+/-52% LOA and 9% with a+/-56% LOA respectively. CONCLUSIONS: CE-MRI has proved to be comparable to SPECT in the assessment of the healed MI mass. Conversely, a high systematic error (high bias and LOA) renders CE-MRI and SPECT assessments of the MI area incomparable. Similarly (high bias and/or LOA) CE-MRI and SPECT estimations of the MI area cannot be compared with functional evaluation by echocardiography or cine-MRI.
Aged↗
Influence of accommodative lag upon the far-gradient measurement of accommodative convergence to accommodation ratio in strabismic patients.
PURPOSE: To determine the influence of the lag of accommodation (LOA) on the accommodative convergence to accommodation (AC/A) ratio measured by the far-gradient method in strabismic patients. METHODS: The AC/A ratio was measured with a distance target viewed with and without -3.00 diopter (D) addition lenses in 63 patients with different types of strabismus (age range, 7-34 years; range of strabismic angle, -60 to +40 prism diopters; refractive error range, -7.33 to +6.63 D). The LOA for the same lens was measured with an open-view-type autorefractometer. The stimulus AC/A ratio and the AC/A ratio adjusted by the individually measured LOA (adjusted AC/A ratio) were compared. RESULTS: The mean +/- SD of the LOA to the -3.00 D lenses was 1.06 +/- 0.43 D. The mean adjusted AC/A ratio was 41% greater than the stimulus AC/A ratio. The LOA differed widely among patients (0.13 to 2.14 D), and a large LOA tended to appear in myopic or young patients. CONCLUSIONS: The AC/A ratio obtained using the conventional far-gradient method is significantly biased by the LOA, and thus does not always represent the actual relationship between accommodation and vergence control systems.
Accommodation, Ocular↗
Rat ultrasonic vocalization in aversively motivated situations and the role of individual differences in anxiety-related behavior.
Our previous work has shown that male Wistar rats, although identical in breeder, age and housing conditions, can differ systematically in their anxiety-related behavior as measured in the elevated plus-maze. Since such individual dispositions can affect the responsiveness in other aversively motivated situations, we asked in a 1st experiment whether such rats might also differ in a test of conditioned fear. Based on their levels of spontaneous open arm avoidance in the elevated plus-maze, 20 adult male Wistar rats were divided into those with "high open arm" (HOA) versus "low open arm" (LOA) time. These rats were then tested in a standard fear conditioning paradigm. During the conditioning procedure, they received 6 tone (3 kHz, 20 s) and shock (0.5 mA, 0.5 s) pairings, each followed by a 60 s inter-stimulus interval. Conditioned responses to the tone were tested 24 h thereafter. During both days, freezing behavior and ultrasonic vocalization were measured. Differences in ultrasonic vocalization between HOA and LOA rats were detected during the conditioning day, where vocalization was more likely in LOA rats. Furthermore, LOA rats emitted calls with higher frequency components than HOA rats. On the subsequent day of testing, the number of animals vocalizing, and the rate of vocalization was decreased, and call differences between groups were no longer detectable. In freezing, differences between HOA and LOA rats were observed on the conditioning day, where LOA rats showed more freezing behavior during the tone/shock intervals. Also, on the test day, they showed more freezing behavior during the tone intervals compared to HOA rats. These results indicate that acute and conditioned responses of rats in a conventional fear conditioning paradigm can depend on individual dispositions of anxiety-related behavior as measured with the elevated plus-maze. In a 2nd experiment, we asked whether exposure to an elevated plus-maze would lead to ultrasonic vocalization, which we tested in rats which had been handled or non-handled prior to testing. Most importantly, we found that none of the animals displayed any vocalization in the plus-maze, neither during a 1st nor a repeated test 1 day later. These data are discussed with respect to the presumed role of ultrasonic vocalization in aversively motivated situations, and the mechanisms, which may account for the behavioral differences between HOA and LOA rats in such tests.
Analysis of Variance↗
A case of loiasis in Rome.
BACKGROUND: Owing to the increase of an immigrant population and of Italian citizens travelling for tourism or on business, it is nowadays possible to observe clinical pictures characteristic of tropical regions, often with indistinct symptoms. One of these is Loa loa infestation, or loiasis, a form of filariasis caused by Loa loa and transmitted by the Chrysops fly. We present the case of a male immigrant from Cameroon. Characteristic symptoms were intense xerosis, mostly of the third inferior part of the legs, intensely pruritic, with numerous lesions from scratching. No benefit was obtained by emollient topics, anti-acarus and systemic antihistamines. METHOD: Serum samples and Giemsa, haematoxylin, haematoxylin + Giemsa concentration-on-membrane stains, have evidenced the presence of Loa loa microfilariae. RESULTS: A diagnosis for L. loa (loiasis) infestation was made. CONCLUSIONS: At the beginning of the migration phenomenon, particularly from Africa, Italian physicians, especially dermatologists, were eagerly looking for 'tropical' diseases; this approach can be defined as 'Salgari's syndrome' from the name of the Italian novelist who, though never travelling out of Italy, had perfectly described environments and habits typical of far away countries. Now, conversely, we have to avoid the opposite approach of considering real tropical diseases as related to social or psychological difficult conditions.
Adult↗
Smoking as a risk indicator for periodontal disease in the middle-aged Vietnamese population.
BACKGROUND: Studies from developed countries have found smoking a significant risk indicator for periodontitis. However, few such studies have been conducted in developing populations, where the natural history of the disease is rarely confounded by treatment and smoking is highly prevalent. AIM: The present study aimed to confirm the consistency, strength and dose-response of the association of smoking with periodontitis measured by loss of attachment (LOA) in a representative middle-aged adult sample from a developing country. METHODS: A cross-sectional study with a multistage stratified random sample was conducted in two provinces of Vietnam. RESULTS: A total of 575 (response: 84.6%) 35-44-year-old subjects were interviewed and periodontally examined. Data were re-weighted to represent the population of the provinces. 28.9% were current smokers (CS), 8.6% former smokers (FS) and 62.5% never-smokers (NS). Number of cigarette pack-years was calculated to divide CS into light smokers, LS < or = 5 pack-years, and heavy smokers, HS 5+ pack-years. The US NIDR protocol was employed for LOA measurement at two sites per tooth for every tooth. HS presented with the highest prevalence of LOA exceeding various thresholds followed by LS (chi2, P < 0.001). The extent of sites with LOA > or = 4 mm and LOA > or = 6 mm was significantly higher among HS and LS compared to NS (ANOVA; P < 0.001). The severity scores of LOA for NS, FS, LS and HS were 2.42, 2.50, 2.64 and 3.05 mm respectively (ANOVA; P < 0.001). Disease cases were defined as having 2+ sites with LOA > or = 5 mm and 1+ site with PD > or = 4 mm. Compared to NS, the odds ratio for periodontitis among heavy smokers was 7.17 (CI: 2.87-17.92, P < 0.001). CONCLUSION: Smoking is a risk indicator for periodontitis among the middle-aged Vietnamese population. To pursue a population prevention approach for periodontitis, dentistry in Vietnam needs to be part of antismoking and smoking cessation programs.
Adult↗
Gene expression and immunolocalization of 15-lipoxygenase isozymes in the airway mucosa of smokers with chronic bronchitis.
15-lipoxygenase (15-LO) has been implicated in the inflammation of chronic bronchitis (CB), but it is unclear which of its isoforms, 15-LOa or 15-LOb, is primarily involved. To detect 15-LO gene (mRNA) and protein expression, we have applied in situ hybridization (ISH) and immunohistochemistry (IHC), respectively, to bronchial biopsies obtained from 7 healthy nonsmokers (HNS), 5 healthy smokers (HS), and 8 smokers with CB, and additionally include the airways of lungs resected from 11 asymptomatic smokers (AS) and 11 smokers with CB. Compared with HNS, biopsies in CB demonstrated increased numbers of 15-LOa mRNA+ cells (median: HNS = 31.3/mm(2) versus CB = 84.9/mm(2), P < 0.01) and protein+ cells (HNS = 2.9/mm(2) versus CB = 32.1/mm(2), P < 0.01). The HS group also showed a significant increase in protein+ cells (HNS = 2.9/mm(2) versus HS = 14/mm(2), P < 0.05). In the resected airways, 15-LOa protein+ cells in the submucosal glands of the CB group were more numerous than in the AS group (AS = 33/mm(2) versus CB = 208/mm(2); P < 0.001). 15-LOa mRNA+ and protein+ cells consistently outnumbered 15-LOb by approximately 7- and 5-fold, respectively (P < 0.01). Quantitative reverse transcriptase polymerase chain reaction of complementary biopsies confirmed the increased levels of 15-LOa in CB compared with that in either HNS or HS (P < 0.05). There was no difference between the subject groups with respect to 15-LOb expression. The numbers of cells expressing mRNA for 15-LOa in CB showed a positive association with those expressing interleukin (IL)-4 mRNA (r = 0.80; P < 0.01). We conclude that the upregulation of 15-LO activity in the airways of HS and of smokers with CB primarily involves the 15-LOa isoform: the functional consequences of its association the upregulation of IL-4 in chronic bronchitis requires further study.
Adult↗
Combined Utilisation of Rapid Assessment Procedures for Loiasis (RAPLOA) and Onchocerciasis (REA) in Rain forest Villages of Cameroon.
BACKGROUND: Individuals with high microfilarial loads of Loa loa are at increased risk of neurologic serious adverse (SAE) events following ivermectin treatment against onchocerciasis. RAPLOA (Rapid Assessment Procedure for loiasis), a newly developed rapid assessment procedure for loiasis that relates the prevalence of key clinical manifestation of loiasis (history of eye worm) to the level of endemicity of the infection (prevalence of high intensity), is a very useful tool to identify areas at potential risk of L. loa post ivermectin treatment encephalopathy. In a perspective of treatment decision making in areas of co-endemicity of loiasis/onchocerciasis, it would be advantageous (both in time and cost savings) for national onchocerciasis control programmes to use RAPLOA and the Rapid epidemiologic assessment for onchocerciasis (REA), in combination in given surveys. Since each of the two rapid assessment tools have their own specificities, the workability of combining the two methods needed to be tested. METHODS: We worked in 10 communities of a forest area presumed co-endemic for loiasis and onchocerciasis in the North-West Province of Cameroon where the mass-treatment with ivermectin had not been carried out. A four-step approach was used and comprised: (i) generating data on the prevalence and intensity of loiasis and onchocerciasis in an area where such information is scarce; (ii) testing the relationship between the L. loa microfilaraemia prevalence and the RAPLOA prevalence, (iii) testing the relationship between the O. volvulus microfiladermia prevalence and the REA prevalence, (iv) testing the workability of combining RAPLOA/REA by study teams in which a single individual can perform the interview for RAPLOA and the nodule palpation for REA. RESULTS: The microfilaraemia prevalence of loiasis in communities ranged from 3.6% to 14.3%. 6 (0.61%) individuals had L. loa microfilarial loads above 8000 mf/ml but none of them attained 30,000 mf/ml, the threshold value above which the risk of developing neurologic SAE after ivermectin treatment is very high. None of the communities surveyed had RAPLOA prevalence above 40%. All the communities had microfiladermia prevalence above 60%. The microfiladermia results could be confirmed by the rapid epidemiologic method (nodule palpation), with all the 10 communities having REA prevalence above 20%. For the first time, this study has demonstrated that the two rapid assessment procedures for loiasis and onchocerciasis can be carried out simultaneously by a survey team, in which a single individual can administer the questionnaire for RAPLOA and perform the nodule palpation for REA. CONCLUSION: This study has: (i) Revealed that the Momo valley of the North West province of Cameroon is hyperendemic for onchocerciasis, but is of lower level of endemicity for L. loa. (ii) Confirmed the previous relationships established between RAPLOA and the L. loa microfilaraemia prevalence in one hand and between the REA and the O. volvulus microfiladermia prevalence in another hand (iii) Shown that RAPLOA and REA could be used simultaneously for the evaluation of loiasis and onchocerciasis endemicity in areas targeted by the African Programme for onchocerciasis Control for community-directed treatment with ivermectin (CDTI).
Journal Article↗
Automated fault-management in a simulated spaceflight micro-world.
BACKGROUND: As human spaceflight missions extend in duration and distance from Earth, a self-sufficient crew will bear far greater onboard responsibility and authority for mission success. This will increase the need for automated fault management (FM). Human factors issues in the use of such systems include maintenance of cognitive skill, situational awareness (SA), trust in automation, and workload. This study examine the human performance consequences of operator use of intelligent FM support in interaction with an autonomous, space-related, atmospheric control system. METHODS: An expert system representing a model-base reasoning agent supported operators at a low level of automation (LOA) by a computerized fault finding guide, at a medium LOA by an automated diagnosis and recovery advisory, and at a high LOA by automate diagnosis and recovery implementation, subject to operator approval or veto. Ten percent of the experimental trials involved complete failure of FM support. RESULTS: Benefits of automation were reflected in more accurate diagnoses, shorter fault identification time, and reduced subjective operator workload. Unexpectedly, fault identification times deteriorated more at the medium than at the high LOA during automation failure. Analyses of information sampling behavior showed that offloading operators from recovery implementation during reliable automation enabled operators at high LOA to engage in fault assessment activities CONCLUSIONS: The potential threat to SA imposed by high-level automation, in which decision advisories are automatically generated, need not inevitably be counteracted by choosing a lower LOA. Instead, freeing operator cognitive resources by automatic implementation of recover plans at a higher LOA can promote better fault comprehension, so long as the automation interface is designed to support efficient information sampling.
Adult↗
Ivermectin in loiasis and concomitant O. volvulus and M. perstans infections.
Two clinical studies were carried out in Gabon, Africa to evaluate the efficacy, safety, and tolerability of ivermectin in the treatment of patients with Loa loa infection. In the first study, 35 patients received single oral doses of ivermectin, 5-200 mcg/kg body weight. Blood microfilariae levels did not decrease after a single oral 5, 10, 30, or 50 mcg/kg dose of ivermectin, but levels did decrease after doses of 100, 150, and 200 mcg/kg. The most efficacious dose was 200 mcg/kg; mean blood microfilariae levels decreased to 12% of mean pretreatment values by day 15 and remained decreased for 28 days. A second study evaluated the safety and efficacy of ivermectin in patients with multifilarial infections. All 17 patients had concomitant Loa loa and O. volvulus infection. M. perstans affected 5 of the patients. Sixteen patients also had infections due to intestinal nematodes. The patients each received single oral doses of 200 mcg/kg ivermectin. Ten days later, the mean Loa loa blood microfilariae level had decreased to 20% of the mean pretreatment level. O. volvulus dermal microfilariae densities were reduced to 2% of the pretreatment levels. A minimal increase in blood microfilaria levels was observed on day 28. In contrast, dermal microfilariae levels remained near zero for the duration of the study. Intestinal infection due to Ascaris was eradicated in all of the affected patients by day 23; efficacy against Trichuris and hookworm infections, however, was poor. All patients tolerated ivermectin well including those with multiple infections.
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