Laboratory Screening Studies Research Articles

Chagas Disease in Children-Case Report

Chagas disease, caused by Trypanosoma cruzi, is considered the most serious parasitosis in America. It is mainly transmitted by triatomics (bugs). The infection causes cardiomyopathies and mega organs of the digestive tract. The diagnosis in the acute phase is by parasitological approach and in the chronic phase, by laboratory screening studies. In Mexico, children under 10 years of age are the most affected. The case of a 12-year-old girl with data suggestive of a bacterial infectious process is reported. with persistent fever, multi-treated with antimicrobials with suspicion of Chagas disease through the route of entry of the parasite with the Romana-Mazza sign.

History of corrosion studies on container materials for the final disposal of VHLW and SF conducted in Belgium

AbstractIn Belgium, an extensive corrosion program on a wide range of metals has been studied as candidate container material, which is considered in the geological disposal concept of high‐level radioactive waste or spent fuel. This paper presents an overview of the corrosion studies initiated by SCK CEN more than 40 years ago. The experiments conducted in these studies were conceived based on early disposal designs, that is, designs in which the radioactive waste was to be enclosed in a metallic overpack that would be directly emplaced in an argillaceous environment. A step‐wise approach was adopted consisting of laboratory screening studies, detailed studies, and demonstration tests. The screening studies included accelerated tests, conducted in a surface laboratory, and exposure tests carried out either in autoclaves or in the field in a surface clay quarry. The detailed studies involved both in situ and laboratory experiments. Gradually, the emphasis shifted from basic research to large‐scale integrated demonstration experiments enabling the simultaneous study of different parameters and/or processes and their coupling.

Molecular detection of Campylobacter species from human and cattle faecal samples in Kilosa District, Tanzania

A growing number of Campylobacter species other than C. jejuni and C. coli have been considered as emerging human and animal pathogens but their contribution to human gastroenteritis is poorly documented. This study aimed at detecting Campylobacter species from human and cattle faecal samples in Kilosa District, Tanzania using molecular techniques without culture. Seventy (70) faecal samples were collected from five diarrheic and 65 non-diarrheic human patients attending Kilosa District Hospital in Tanzania from July to October 2019. During the same period, 30 faecal samples were also collected from healthy cattle in the same district. Genus and species identification of Campylobacter was conducted on the samples using molecular techniques [the polymerase chain reaction (PCR) and 16S rRNA sequencing]. Phylogenetic analysis was carried out by comparison of the 16S rRNA gene sequences to reference strains by the Neighbor-Joining method in MEGA X. Campylobacter species detection rate by PCR was 65.7% (46/70) and 20% (6/30) in humans and cattle, respectively. There were five human diarrheic cases, four of which were positive for Campylobacter and of these, two were children ≤15 years of age. In humans, 16S rRNA sequencing revealed that C. concisus was the most predominant species occurring at a frequency of 37.8% (14/37), followed by uncultured Campylobacter spp. 24.3% (9/37) and C. hominis 21.6% (8/37). The least represented species were C. jejuni and C. lanienae, all occurring at 2.7% (1/37). In cattle, five (100%) sequenced PCR products matched with C. lanienae. Phylogenetic analysis revealed that with the exception of C. lanienae, 16S rRNA sequences of Campylobacter species were closely related to the reference strains used (Percent identity: 90.51-96.56%). Based on our findings, we recommend that molecular techniques, mainly PCR be adopted for the direct detection of Campylobacter species during laboratory screening and surveillance studies.

A Critical Review of Alcohol Administration Guidelines in Laboratory Medication Screening Research: Is It Time to Include Treatment Seekers?

Human laboratory studies play an important role in alcohol use disorder (AUD) medication development. Medications that are found to be safe and effective during human laboratory screening will then move to more expensive clinical trials in patient populations. Given the gatekeeping role of human laboratory studies in the medication development pipeline, it is critical that these studies accurately forecast how pharmacotherapies will perform under true-to-life clinical conditions. On the other hand, the design of these studies also must adhere to ethical guidelines: certain aspects of clinical reality cannot be incorporated into screening studies because doing so might place the participant at risk for harm or breach other ethical guidelines. Conventions exist that guide the resolution of these conflicting ideals. This article considers the practice of recruiting non-treatment-seeking heavy drinkers to participate in laboratory screening studies. By convention, volunteers are excluded from laboratory screening studies that involve alcohol administration if they are deemed "treatment seeking," meaning that they recently stopped drinking or are motivated to do so. Although this common practice may reduce risk to participants, findings may not accurately predict medication effects on treatment seekers. Indeed, there is empirical evidence that treatment seekers differ from nontreatment seekers in their responses to medications (Neuropsychopharmacology 2017a; 42: 1776; Am J Drug Alcohol Abuse 2017b; 43: 703; J Psychiatr Res 2006; 40: 383). Here, we argue for the importance of recruiting treatment seekers for this research due to their qualitative difference from nontreatment seekers. We argue that these individuals should be the default population in human laboratory medication screening studies. We conclude by discussing 2 case examples of medication experiments led by our research groups that involved administering medications to treatment seekers.

Erythema nodosum.

Erythema nodosum can be associated with a number of systemic diseases. There is, however, a paucity of information in the pediatric literature on this condition. The purpose of this article is to familiarize pediatricians with the evaluation, diagnosis, and treatment of erythema nodosum. A PubMed search was completed in Clinical Queries using the key terms "erythema nodosum". Clinically, erythema nodosum presents with a sudden onset of painful, erythematous, subcutaneous nodules mainly localized to the pretibial areas. Lesions are usually bilateral and symmetrical, ranging from 1 to 5cm in diameter. Erythema nodosum may be associated with a variety of conditions such as infection, medications,sarcoidosis, pregnancy, inflammatory bowel disease, vaccination, autoimmune disease, malignancy, and miscellaneous causes. The condition is idiopathic in approximately 50% of cases. The diagnosis is mainly clinical with biopsy reserved for atypical cases. To evaluate for the underlying cause, some basic laboratory screening studies are worthwhile in most cases and include a complete blood cell count, erythrocyte sedimentation rate and/or C-reactive protein, throat swab culture, antistreptococcal O titers, and a chest radiograph. Other tests should be individualized, guided by the history and physical examination results. Most cases of erythema nodosum are self-limited and require no treatment. Bed rest and leg elevation are generally recommended to reduce the discomfort. Nonsteroidal anti-inflammatory drugs are the first-line treatment for pain management. As erythema nodosum is often a cutaneous manifestation of a systemic disease, a thorough search should be performed to reveal the underlying cause.

Enfermedad de Chagas en México

Chagas disease, which is caused by Trypanosoma cruzi, is considered to be the most serious parasitic disease in America. It is transmitted mainly by triatominae ("kissing bugs"). Mazzoti reported the first two human cases in Mexico. The form of transmission is by parasites entering the organism in feces of the insect, by blood transfusion, from mother to child, by organ transplant and laboratory accidents. In Mexico, 1.1 million people are estimated to be infected; the incidence in 2012 was 0.70 per 1,00,000 population. In 2017, the highest incidence rates were registered in Yucatán, Oaxaca and Hidalgo. The infection causes cardiomyopathies and mega-organs of the digestive tract. Diagnosis in the acute phase is by parasitological approach and, in the chronic phase, by laboratory screening studies. In Mexico's blood banks, screening for Chagas disease is mandatory; from 2007 to 2016, seroprevalence has decreased from 0.40 to 0.32 due to the improvement of donor selection processes and the ad hoc questionnaire. The targets of the parasite are neurons and smooth and myocardial muscle cells. The association of neuronal and smooth muscle destruction defines the presentation of chagas mega-syndromes. Initial manifestations of the disease can go unnoticed; 5% show apparent signs and symptoms and 30% will progress to the chronic asymptomatic phase. Currently available treatments have effect in the acute phase. For the control of Chagas disease, the Specific Action Program for the Prevention and Control of Chagas Disease (PAE Chagas 2013-2018) is available to initiate activities aimed at eliminating transfusion and congenital transmission and controlling vector transmission. The success of medical care depends on oportune detection, early etiological treatment and coverage broadening. On the other hand, monitoring and screening of pregnant women living in risk areas and blood and organ donors universal screening will enable the elimination congenital and transfusion transmission.

Laboratory assessment of the allelopathic effects of fine leaf fescues.

Laboratory screening studies were conducted to evaluate the allelopathic potential of fine leaf fescues. Of the seven accessions selected from prior field evaluations for weed-suppressive ability, all inhibited root growth of large crabgrass and curly cress in laboratory assays. Grown in agar as a growth medium and in the presence of living fescue seedlings for 14 or 21 days, test species were sensitive depending on the fescue cultivars. Growth inhibition increased when fescue was grown for increasing periods of time in agar. Seedling fescues produced significant quantities of bioactive root exudates, which were released into the agar medium. Bioactive root exudates were extracted from living fescue roots by using methylene chloride. Shoot tissue was extracted in water and the aqueous extract was partitioned against hexane, ethyl acetate, and methylene chloride. Extracts were tested for inhibitory activity on seedling growth as measured by inhibition of curly cress germination and radicle elongation. Root exudates were more toxic (70% inhibition) than shoot extracts (up 40% inhibition), when formulated at 0.25 mg/ml concentration. Light microscopy and transmission electron microscopy were utilized in an attempt to identify the cellular location of production of secondary products contained in bioactive root exudates. Ultrastructural analysis indicated that the exudate is produced in actively dividing tips of fibrous root cells. The mode of release of these exudates into the environment remains unknown.

Chronic Diarrhea Due to Surreptitious Use of Bisacodyl: Case Reports and Methods for Detection

Surreptitious abuse of laxatives is a common cause of severe chronic diarrhea. Standard laboratory screening studies of urine and stool specimens may identify phenolphthalein, diuretics, and magnesium-containing agents. An assay for bisacodyl, a commonly used over-the-counter laxative, however, is not included in routine screening tests. Herein we describe two patients with chronic watery diarrhea of large volume; analysis of stool and urine samples revealed that surreptitious use of bisacodyl was the cause. In one patient, nonspecific inflammatory changes of the colonic mucosa were noted on biopsy, and fecal leukocytes were detected in both patients. In a prospective study of eight patients who received bisacodyl as part of a preparation for colonoscopy, we analyzed serial urine samples for bisacodyl diphenol during a 48-hour period. This metabolite was found in seven of eight hydrolyzed urine samples obtained 12 hours after oral administration of bisacodyl but not in samples obtained 24 and 48 hours after ingestion of the laxative. We recommend that urinalysis and, in some cases, stool analysis for bisacodyl should be considered in the diagnostic assessment for surreptitious use of laxatives.

DETERMINING “REAL WORLD” BIODEGRADATION RATES

Environmental Toxicology and ChemistryVolume 4, Issue 2 p. 129-130 EditorialFree Access Determining “real world” biodegradation rates Philip H. Howard, Philip H. Howard Editor Environmental ChemistrySearch for more papers by this author Philip H. Howard, Philip H. Howard Editor Environmental ChemistrySearch for more papers by this author First published: April 1985 https://doi.org/10.1002/etc.5620040201Citations: 8AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. References 1 Howard, P.D. and S. Banerjee. 1984. Interpreting results from biodegradability tests of chemicals in water and soil. Environ. Toxicol. Chem. 3: 551– 562. 2 U.S. Environmental Protection Agency. 1983. Bio-degradation Kinetics Workshop, October 18–20, Gulf Breeze, Florida. 3 Simkins, S. and M. Alexander. 1984. Models for mineralization kinetics with the variables of substrate concentration and population density. Appl. Environ. Microbiol. 47: 1299– 1306. 4 Boethling, R.S. and M. Alexander. 1979. Effect of concentration of organic chemicals on their biodegradation by natural microbial communities. Appl. Environ. Microbiol. 37: 1211– 1216. 5 Subba-Rao, R.V., H.E. Rubin and M. Alexander. 1982. Kinetics and extent of mineralization of organic chemicals at trace levels in freshwater and sewage. Appl. Environ. Microbiol. 43: 1139– 1150. 6 Rubin, H.E. and M. Alexander. 1983. Effects of nutrients on the rate of mineralization of trace concentrations of phenol and p-nitrophenol. Environ. Sci. Technol. 17: 104– 107. 7 Wang, Y.-S., R.V. Subba-Rao and M. Alexander. 1984. Effect of substrate concentration and organic and inorganic compounds on the occurrence and rate of mineralization and cometabolism. Appl. Environ. Microbiol. 47: 1195– 1200. 8 Larson, R.J., G.G. Clinckemaillie and L. VanBelle. 1981. Effect of temperatures and dissolved oxygen on biodegradation of nitrilotriacetate. Water Res. 15: 615– 620. 9 Bartholomew, G.W. and F.K. Pfaender. 1983. Influence of spatial and temporal variations on organic pollutant biodegradation rates in an estuarine environment. Appl. Environ. Microbiol. 45: 103– 109. 10 Zobell C.E. 1943. The effect of solid surfaces upon bacterial activity. J. Bacteriol. 46: 39– 56. 11 Wright, R.T. 1979. Natural heterotrophic activity in estuarine and coastal waters. In A.W. Bourquin and P.H. Pritchard, eds., Microbial Degradation of Pollutants in Marine Environments. EPA-600/9-79-012. U. S. Environmental Protection Agency, Washington, DC. 12 Wylie, G.D., J.R. Jones and B. Johnson. 1982. Evaluation of the river dieaway biodegradation test. J. Water Pollut. Contr. Fed. 54: 1231– 1236. 13 Larson, R. 1983. Comparison of biodegradation rates in laboratory screening studies with rates in natural waters. Resid. Rev. 85: 159– 171. 14 Boethling, R.S. 1984. Biodegradation testing of insoluble chemicals. Environ. Toxicol. Chem. 3: 5– 7. 15 Spain, J.C. and P.A. Van Veld. 1983. Adaptation of natural microbial communities to degradation of xenobiotic compounds: effects of concentration, exposure time, inoculum, and chemical structure. Appl. Environ. Microbiol. 45: 428– 435. Citing Literature Volume4, Issue2April 1985Pages 129-130 ReferencesRelatedInformation

Comparison of biodegradation rates in laboratory screening studies with rates in natural waters.

Microbial degradation (biodegradation) of organic chemicals is generally recognized as an important removal mechanism in natural systems. For chemicals which reach the aquatic environment in significant quantities, estimates of biodegradability are key in assessing the overall hazard associated with the use of a particular chemical (Larson 1980). Estimates of biodegradability are often generated in the laboratory via biodegradability screening studies (Larson 1979). In screening studies, compounds are tested as sole carbon and energy sources at relatively high (mg/L) concentrations with a dilute synthetic salts solution as the test medium. Degradation is measured nonspecifically by following the amount of carbon dioxide produced or oxygen consumed during microbial metabolism, and soil or sewage are typically used as the source of degradative microorganisms. These experimental conditions do not accurately simulate natural aquatic environments, where chemical concentrations are low (μg/L) and a variety of nutrient conditions and microbial species exist. As a result, legitimate questions have been raised about the reliability of biodegradability screening tests, and the ability of such tests to predict fate of compounds in the “real world” (Alexander 1981).

Studies of Drag Reduction Conducted over a Broad Range of Pipeline Conditions when Flowing Prudhoe Bay Crude Oil

The effects of solvent viscosity, bulk velocity, and pipe diameter on drag reduction have been investigated in order to ascertain the feasibility of utilizing polymer drag‐reducing additives to increase the flow rate in the Trans‐Alaska Pipeline. Laboratory screening studies were performed in 1‐ and 2‐in. diam flow loops to determine the best commercially available additive for the application. Field tests in a 14‐in. crude pipeline and in the 48‐in. Trans‐Alaska Pipeline confirmed the material's effectiveness in large‐scale applications. This research program has resulted in the use of drag‐reducing additive in the Trans‐Alaska Pipeline as a temporary replacement for unconstructed pump stations. The effect of additive concentration was investigated over a range of 5 to 25 ppm. The crude‐oil flow conditions that were studied included solvent kinematic viscosities of 9 to 50 mm2/sec (9 to 50 cs), Reynolds numbers of 4000 to 300000, wall shear rates of 100 to 2000 sec−1, as well as inside pipe diameters fro...

Field and Laboratory Selection for Resistance in Soybeans to the Mexican Bean Beetle 13

More than 350 soybean lines were screened for host plant resistance to Epilachna varivestis Mulsant in field and laboratory experiments conducted in 1971 and 1972. Entries with low feeding damage scores in the field were screened in the laboratory in a larval antibiosis test and an adult seedling-preference test. Those entries which performed well in both the field and laboratory studies were retested and run through a 3rd laboratory test, the larval leaf disk test. Laboratory studies confirmed moderate levels of resistance found in the field in the following soybean lines: P.I. 90481, P.I. 96089, P.I. 157413, V–21, and V–156. Antibiosis and nonpreference were 2 mechanisms responsible. The performance of several selected lines in both field and laboratory screening studies indicated that the laboratory methods were effective for selecting lines with resistance and identifying in some instances the mechanism of resistance.

Laboratory Profile Screening in Family Practice

Reports from private medical offices of data obtained when routine laboratory screening studies were made a part of each health evaluation have not been common. This report analyzes 2,919 laboratory profiles secured on 1,204 patients examined in a five-year period. Repeated profile screening has certain limitations but contributes much to a physician's understanding of each patient's health status. Laboratory screening is economical and should be considered along with other diagnostic and screening modalities. The pathologist skilled in laboratory medicine should be included as a member of the family physicianconsultant team in continuing and comprehensive family medical care. Routine laboratory screening, as part of each periodic health evaluation, offers the family physician a great challenge. A program of collaborative research in this aspect of laboratory medicine would appear justified.