Trend of soil salinization in Africa and implications for agro-chemical use in semi-arid croplands.

Soil salinization is a gradual degradation process that begins as a minor problem and grows to become a significant economic loss if no control action is taken. It progressively alters the soil environment which eventually negatively affects plants and organism that were not originally adapted for saline conditions. Soil salinization arises from diverse sources such as side-effects of long-term use of agro-chemicals, saline parent rocks, periodic inundation of soil with saline water, etc. In Africa, soil salinization has not been adequately documented particularly in the croplands. The objective of this study was to identify trends of cropland salinization in Africa and how its relationship with long-term land use practices affected the soil environment. The study analysed soil salinization between 1965 and 2020 using measured electrical conductivity (EC), spatial modelling with environmental covariates, and national statistics on cropland expansion and application of mineral fertilizers, herbicides, and pesticides. The results showed increasing trends of EC in Africa due to climatic and land use drivers. Increasing trends of EC, which evidenced salinization, was found in 31 million hectares of topsoils and 18 million hectares of subsoils. About 2 million hectares of croplands were depicted with salinization and >25 million hectares at the risk of salinization in the arid and semi-arid areas. The study also found statistical relationships between semi-arid cropland salinization and trends of agro-chemical use and cropland sizes. There were significant (p < 0.001) positive correlations between semi-arid cropland salinization and trends of cropland expansion and applied nitrogenous fertilizers. It found that increasing trend of applied mineral nitrogenous fertilizers could double the odds of salinization in semi-arid croplands while cropland expansion could increase the odds of semi-arid cropland salinization by >10 %. These findings present ground-breaking baseline information for future works on sustainable land-use practices that can control cropland soil salinization in Africa.

Infectious meningitis and encephalitis in adults in Denmark: a prospective nationwide observational cohort study (DASGIB).

OBJECTIVES: To monitor epidemiological trends of infectious meningitis (bacterial and viral) and encephalitis in Denmark. METHODS: Nationwide prospective observational study of all cases of proven community-acquired infectious meningitis and encephalitis in adults treated in all infectious diseases departments in Denmark from 1 January 2015 to 30 June 2016. We included data on symptoms, aetiology, treatment and outcome assessed by the Glasgow Outcome Scale (GOS) 30 days after discharge. GOS 1-4 was categorized as unfavourable outcome. RESULTS: During 18 months of observation, we identified 252 cases of viral meningitis (3.6/100 000/year), 214 cases of bacterial meningitis (3.1/100 000/year) and 96 cases of infectious encephalitis (1.4/100 000/year). In bacterial meningitis, Streptococcus pneumoniae was the most frequent infectious agent (n = 101) followed by Staphylococcus aureus (n = 24) and ß-haemolytic streptococci (n = 14). Meningococcal meningitis was rare (n = 11). In encephalitis, herpes simplex virus type 1 was most common (n = 37) followed by varicella zoster virus (n = 20), whereas varicella zoster virus (n = 61) was most common in viral meningitis followed by enterovirus (n = 50) and herpes simplex virus type 2 (n = 46). Case fatality and unfavourable outcome occurred in 31/214 (15%) and 96/214 (45%) with bacterial meningitis and in 5/96 (5%) and 55/89 (62%) with encephalitis. For viral meningitis, unfavourable outcome occurred in 41/252 (17%). CONCLUSIONS: The epidemiology and clinical presentation of the examined central nervous system infections differed considerably and bacterial meningitis was more frequent than previously estimated. Overall prognosis remains poor for bacterial meningitis and encephalitis. Prospective nationwide clinical databases of central nervous system infections may be superior to epidemiological monitoring based on notifications or laboratory systems.

A nationwide study of comorbidity and risk of reinfection after Staphylococcus aureus bacteraemia.

BACKGROUND: Data on risk factors and rates of reinfection associated with Staphylococcus aureus bacteraemia (SAB) are sparse. METHODS: We conducted a nationwide cohort study of cases of SAB diagnosed between 1995 and 2008. Reinfection was defined as an episode of SAB more than 90 days after the initial episode of SAB. Comorbidity was evaluated by the Charlson Comorbidity Index (CCI). Cox proportional hazards modelling was used to estimate hazard rates (HR). RESULTS: Of 10,891 eligible patients, 774 (7.1%) experienced reinfection a median of 458 days (range 90-5021 days) after their primary SAB episode corresponding to a reinfection rate of 1459 (95% confidence interval (CI): 1357-1562) per 100,000 personyears. In multivariate analysis, sex, origin, a vascular or peritoneal device, endocarditis and comorbidity were associated with reinfection. The association was more than two-fold higher among patients in dialysis and for patients with severe comorbidity (CCI ≥ 2). HIV infection (Hazard ratio (HR) 6.18, 95% CI: 4.17-9.16), renal disease (HR 3.92, 95% CI: 3.22-4.78), diabetes with complications (HR 2.11, 95% CI: 1.69-2.62), diabetes without complications (HR 1.61, 95% CI: 1.34-1.93), mild (HR: 1.94, 95% CI: 1.36-2.76) and severe liver disease (HR 2.08, 95% CI: 1.08-4.03), peptic ulcer (HR 1.33, 95% CI: 1.03-1.72), and paraplegia (HR 2.15, 95% CI: 1.02-4.54) were each associated with an increased risk of reinfection. CONCLUSIONS: Patients with previous SAB have a 60-fold higher risk of SAB compared to the general population. Patients with HIV infection, renal disease, diabetes, liver disease, peptic ulcer and paraplegia had the highest rates of reinfection.

Simultaneous administration of vitamin A and DTP vaccine modulates the immune response in a murine cerebral malaria model.

The World Health Organisation recommends vitamin A supplementation (VAS) to children aged 6 months to 5 years in low-income countries, and for logistic reasons, this has been linked to routine childhood immunizations. Observational studies suggest that VAS given with diphtheria-tetanus-pertussis (DTP) vaccine may increase mortality from non-targeted diseases. We investigated the non-targeted effect of pretreatment with VAS and DTP vaccine in a murine model of experimental cerebral malaria. Our a priori hypothesis was that VAS/DTP would aggravate the infection. We found that the effect of VAS and DTP depended on pathogenesis; VAS/DTP tended to increase parasitaemia and significantly depressed cytokine responses in mice, which developed cerebral malaria, but this was not seen in mice dying of anaemia. The divergent effect according to pathogenesis may help elucidate why VAS has divergent effects on different diseases in humans. Our results support the hypothesis that immunological effects of VAS/DTP may have detrimental implications for disease outcomes.

In-depth validation of acridine orange staining for flow cytometric parasite and reticulocyte enumeration in an experimental model using Plasmodium berghei.

Flow cytometry is potentially an effective method for counting malaria parasites, but inconsistent results have hampered its routine use in rodent models. A published two-channel method using acridine orange offers clear discrimination between the infected and uninfected erythrocytes. However, preliminary studies showed concerns when dealing with Plasmodium berghei-infected blood samples with high numbers of reticulocytes. In hyperparasitemic or chronic P. berghei infection, enhanced erythropoietic activity results in high numbers of circulating immature reticulocytes. We show that even though the protocol offered good discrimination in newly infected animals, discrimination between infected erythrocytes and uninfected reticulocytes became difficult in animals with hyperparasitemia or chronic infections maintained with subcurative treatment. Discrimination was especially hampered by increased nucleic acid content in immature uninfected reticulocytes. Our data confirms that though flow cytometry is a promising analytical tool in malaria research, care should still be taken when analysing samples from anemic or chronically infected animals.

Infectious CNS disease as a differential diagnosis in systemic rheumatic diseases: three case reports and a review of the literature.

BACKGROUND: Immunosuppressive treatment of rheumatic diseases may be associated with several opportunistic infections of the brain. The differentiation between primary central nervous system (CNS) involvement and CNS infection may be difficult, leading to delayed diagnosis. OBJECTIVE: To differentiate between CNS involvement and CNS infection in systemic rheumatic diseases. METHODS AND RESULTS: Three patients with either longstanding or suspected systemic rheumatic diseases (systemic lupus erythematodes, Wegener's granulomatosis, and cerebral vasculitis) who presented with various neuropsychiatric symptoms are described. All three patients were pretreated with different immunosuppressive drugs (leflunomide, methotrexate, cyclophosphamide) in combination with corticosteroids. Magnetic resonance imaging of the brain was suggestive of infectious disease, which was confirmed by cerebrospinal fluid analysis or stereotactic brain biopsy (progressive multifocal leucoencephalopathy (PML) in two and nocardiosis in one patient). DISCUSSION: More than 20 cases of PML or cerebral nocardiosis in patients receiving corticosteroids and cytotoxic drugs for rheumatic disease have been reported. The clinical aspects of opportunistic CNS infections and the role of brain imaging, cerebrospinal fluid analysis and stereotactic brain biopsy in the differential diagnosis are reviewed.

Outcome of endoscopic sphincterotomy in patients with pain of suspected biliary or papillary origin and inconclusive cholangiography findings.

BACKGROUND AND STUDY AIMS: We prospectively studied the outcome of endoscopic sphincterotomy in symptomatic patients with elevated liver enzyme levels but no clear evidence of biliary pathology on transabdominal ultrasound and diagnostic endoscopic retrograde cholangiography (ERC). METHODS: 29 consecutive patients with biliary-type pain (two or more out of eight criteria), elevated liver enzyme levels and no evidence of gallstones or significant common bile duct dilatation were evaluated. Elevated bilirubin levels (up to 7.2 mg/dl) were found in 18 patients. The majority of patients (n = 21) had a gallbladder in situ. The findings from bile duct exploration following sphincterotomy were recorded, and pain (as measured by visual analogue scale) as well as laboratory findings was assessed. RESULTS: Wire-guided sphincterotomy was successful in all patients while uncomplicated pancreatitis occurred in one instance. In 16 patients (55%) there was macroscopic evidence of small stones (n = 2), sludge (n = 12) or both (n = 2) following bile duct exploration. In addition, microscopy showed bile crystals in all four patients who had no macroscopic findings. All four patients with elevation of pancreatic enzymes prior to treatment, and four of those eight patients with previous cholecystectomy, showed evidence of biliary pathology. The initial median pain intensity was 8 (range 1-10); 26 patients became pain-free within 3 months following endoscopic sphincterotomy. While 26 of 28 patients (93%) remained asymptomatic over a median follow-up period of 19 months (range 12-26), one died of an unrelated malignancy 6 months after therapy. CONCLUSIONS: Endoscopic sphincterotomy may be acceptable in patients with typical clinical presentation suggesting a papillary or biliary origin of pain without further diagnostic work-up. Contrary to expectations, diagnostic ERC was insensitive in detection of the biliary etiology of symptoms in this selected group of patients.

Determination of 5-(p-hydroxyphenyl)-5-phenylhydantoin and studies relating to the disposition of phenytoin in man.

A gas chromatographic on-column methylation technique was developed for the routine laboratory determination of 5-(p-hydroxyphenyl)-5-phenylhydantoin (p-HPPH), the principal urinary product of phenytoin )PHT) metabolism in man. 5-(p-Hydroxyphenyl)-5-(p-tolyl)hydantoin (HMPPH), a new internal standard, was synthesized and evaluated against 5-phenyl--5-(p-tolyl)hydantoin (MPPH), the compound normally used as the internal standard in p-HPPH assays. HMPPH withstood the challenges of intralaboratory quality control checks and tests of precision of p-HPPH values at times when MPPH provided erratic and unreliable values. Both an enzyme and acid treatment of urine were studied for the purpose of hydrolysis of p-HPPH-glucuronide, the form in which p-HPPH is excreted in urine. The use of both treatments in studies of three different patient urines pointed to the conclusion that acid-catalyzed decomposition of PHT dihydrodiol, a minor urinary metabolite of PHT in man, was unimportant from the analytical point of view, contributing little if anything to total urinary p-HPPH content. Some aspects of PHT disposition, as evidenced by studies of PHT plasma levels and p-HPPH urinary outputs in individual patients, are discussed.