The Development of a Direct Homologous Radioimmunoassay for Serum Cortisol

Peer Reviewe

Cyanogenesis inhibits active defense reactions in plants.

In the course of fungal attack on the cyanogenic rubber tree (Hevea brasiliensis Muell.-Arg.) HCN is liberated from infected tissue. The HCN interferes with plant host and fungal pathogen. It becomes inhibitory to active defense responses which are dependent on biosynthetic processes as far as a threshold concentration is transgressed

SPIN-MIMS simplifying the SPIN-MAS instrumentation for online measurement of 15N-abundances of ammonium, nitrite and nitrate in aqueous solutions

Common methods for measuring selectively the 15N abundances in individual N-species such as NH4+, NO2- and NO3- in samples with multiple N-species are laborious and time consuming. The SPIN-MAS technique (Stange et al. 2007) offers an automated, rapid and selective determination of 15N abundances in NH4+, NO2- and NO3- in aqueous samples. During a SPIN-MAS measurement one of three different reaction solutions is mixed with the aqueous sample in a Sample Preparation unit for Inorganic N-species (SPIN). The reaction solution is chosen in dependence on the N-species of interest. The gaseous reaction products (N2 or NO) are then conducted to a quadrupole mass spectrometer (MAS) in a helium stream. This measurement technique is not commonly used due to its complex instrumentation. The instrumentation can be significantly simplified by the use of a membrane inlet mass spectrometer (MIMS). The presented SPIN-MIMS approach relies on the use of a reaction capillary in which the sample containing the N-species of interest is mixed with the corresponding reaction solution. The mixture of reaction solution and sample is pumped from the reaction capillary directly to the membrane inlet of the mass spectrometer. The reaction products (N2 or NO) formed during the reaction of NH4+, NO2- and NO3- with the reaction solutions are passed through the gas-permeable membrane of the inlet directly into the ion source of the mass spectrometer. 15N standards with different at% 15N (NH4+, NO2- and NO3- respectively in dist. Water) were used to assess the performance of the system. Overall, SPIN-MIMS measurements showed a good agreement between measured and expected 15N abundances (range 0.36 – 10 at% 15N deviations: <0.5 at% 15N for NH4+-, <0.23 for NO2-- and <0.15 at% 15N for NO3-- standards)

Surface structure of Hevea leaves and its importance for the interaction with fungal plant pathogens and for plant systematics.

Resumo apresentado no XXI Congresso Brasileiro de Fitopatologia, Salvador, 1988

Neuroinflammatory disorders of the brain and inner ear: a systematic review of auditory function in patients with migraine, multiple sclerosis, and neurodegeneration to support the idea of an innovative ‘window of discovery’

Background: Hearing can be impaired in many neurological conditions and can even represent a forme fruste of specific disorders. Auditory function can be measured by either subjective or objective tests. Objective tests are more useful in identifying which auditory pathway (superior or inferior) is most affected by disease. The inner ear’s perilymphatic fluid communicates with the cerebrospinal fluid (CSF) via the cochlear aqueduct representing a window from which pathological changes in the contents of the CSF due to brain inflammation could, therefore, spread to and cause inflammation in the inner ear, damaging inner hair cells and leading to hearing impairment identifiable on tests of auditory function. Methods: A systematic review of the literature was performed, searching for papers with case–control studies that analyzed the hearing and migraine function in patients with neuro-inflammatory, neurodegenerative disorders. With data extracted from these papers, the risk of patients with neurological distortion product otoacoustic emission (DPOAE) was then calculated. Results: Patients with neurological disorders (headache, Parkinson’s disease, and multiple sclerosis) had a higher risk of having peripheral auditory deficits when compared to healthy individuals. Conclusion: Existing data lend credence to the hypothesis that inflammatory mediators transmitted via fluid exchange across this communication window, thereby represents a key pathobiological mechanism capable of culminating in hearing disturbances associated with neuroimmunological and neuroinflammatory disorders of the nervous system

Clostridium difficile infection.

Infection of the colon with the Gram-positive bacterium Clostridium difficile is potentially life threatening, especially in elderly people and in patients who have dysbiosis of the gut microbiota following antimicrobial drug exposure. C. difficile is the leading cause of health-care-associated infective diarrhoea. The life cycle of C. difficile is influenced by antimicrobial agents, the host immune system, and the host microbiota and its associated metabolites. The primary mediators of inflammation in C. difficile infection (CDI) are large clostridial toxins, toxin A (TcdA) and toxin B (TcdB), and, in some bacterial strains, the binary toxin CDT. The toxins trigger a complex cascade of host cellular responses to cause diarrhoea, inflammation and tissue necrosis - the major symptoms of CDI. The factors responsible for the epidemic of some C. difficile strains are poorly understood. Recurrent infections are common and can be debilitating. Toxin detection for diagnosis is important for accurate epidemiological study, and for optimal management and prevention strategies. Infections are commonly treated with specific antimicrobial agents, but faecal microbiota transplants have shown promise for recurrent infections. Future biotherapies for C. difficile infections are likely to involve defined combinations of key gut microbiota

Dietary fiber source and stage of gestation impact water balance, fecal physicochemical properties, serum electrolytes, and markers of gut motility in sows

The study aimed to evaluate the impact of carbohydrase supplementation, soluble fiber from sugar beet pulp (SBP; 20%), and insoluble fiber from corn dried distillers grains (DDGS; 20%) on water balance, serum electrolytes, gut motility, and fecal physicochemical properties in gestating sows. Thirty-six sows, with an initial body weight of 186 ± 4.6 kg, balanced by parity, were assigned randomly to a 2×2 factorial arrangement of treatments from day 28 to 109 of gestation. The factors were fiber type (insoluble (IF; 355 g/d) or soluble (SF; 98 g/d)) and enzyme supplementation (Rovabio Advance P10). The feeding level was 2.1 kg per day. Two 8-day metabolism periods occurred during mid- (days 50-59) and late-gestation (days 99-108). Fecal samples for physicochemical property analysis and serum samples were taken on day 1 of each period. Water balance was measured from days 4-7, with a water allowance set at 80 mL/kg of body weight per day. Data were analyzed using a linear mixed model, with parity as a random effect and fiber, enzyme, period, and their interactions as fixed effects. Daily water allowance was used as a covariate when necessary. Urine output increased by 22.3% in sows fed IF compared to SF, and by 30.5% from mid- to late-gestation (Fiber, Period P<0.05). Fecal moisture was 21.8% higher in sows fed SF and increased by 12.3% from mid- to late-gestation (Fiber, Period P<0.05). The SF treatment increased fecal water holding capacity (P<0.001) and fecal water binding capacity by 76.6% (P=0.044). Regardless of diet, fecal water binding capacity increased in late gestation (Period P=0.035). Urine output increased by 30.5% in late gestation (Period P=0.028) and fecal moisture output increased by 12.3% (Period P=0.015). Serum sodium and chloride concentrations were increased in late gestation (P<0.05). Plasma cholecystokinin tended to be 28% greater in sows fed SF (P=0.070), and motilin levels decreased among all groups from mid- to late-gestation (Fiber×Enzyme×Period P=0.006). Circulating 5-Hydroxytryptamine decreased in late gestating sows fed carbohydrases (Period×Enzyme P=0.002), as well as sows fed SF (Fiber P=0.004). These findings suggest a redistribution of water in the gastrointestinal tract of late gestational sows fed SF, altering fecal hydration and gut motility