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The aim of the present study was to determine the in-vitro susceptibility of Toxoplasma gondii to dihydrofolate rcductase inhibitors and sulphonamides alone, and in combination. It was found that pyrimethamine had the most potent anti-Toxoplasma activity, while sulphadiazine, sulphamethoxazole and sul-phametrole were approximately equally effective, but only at a high concentration. The 50% inhibitory concentration of sulphamethoxazole was determined using different fixed concentrations of pyrimethamine or trimethoprim. It was found that a ten-fold increment of the concentration of pyrimethamine, reduced the IC50 of sulphamethoxazole 1000 times. The influence of trimethoprim on the IC50 of sulphamethoxazole was less concentration dependent. Addition of dihydrofolate or tetrahydrofolate did not influence the IC50 of pyrimethamine. In conclusion, the present dose recommendations for sulphonamides, when combined with pyrimethamine, may be unnecessarily high. There may be a justification for dose reduction of sulphonamides in order to prevent side effects. [ABSTRACT FROM PUBLISHER]

Acute ischemic stroke occurs when a thrombus obstructs a cerebral artery, leading to sub-optimal blood perfusion to brain tissue. A recently developed, preventive treatment is the endovascular stroke treatment (EVT), which is a minimally invasive procedure, involving the use of stent-retrievers and/or aspiration catheters. Despite its increasing use, many critical factors of EVT are not well understood. In this respect, in vitro, and in silico studies have the great potential to help us deepen our understanding of the procedure, perform further device and procedural optimization, and help in clinical training. This review paper provides an overview of the previous in vitro and in silico evaluations of EVT treatments, with a special emphasis on the four main aspects of the adopted experimental and numerical set-ups: vessel, thrombus, device, and procedural settings., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Group A rotaviruses (RVAs) are the main etiological agent of infantile diarrhea in both humans and animals worldwide. A limited number of studies have investigated the molecular characteristics of RVA strains in stool specimens of rabbits, with only a few lapine RVA strains isolated and (partially) characterized to date. The most common G/P-genotype combinations found in rabbits are G3P[14] and G3P[22]. In this study a RVA strain was isolated from the small intestine of a 9-week-old rabbit from an infected laboratory rabbit colony. The RVA strain RVA/Rabbit-tc/NLD/K1130027/2011/G6P[11] was shown to possess the typical bovine G6 and P[11] genotypes. The complete genome of this unusual lapine strain was sequenced and characterized. Phylogenetic analyses of all 11 gene segments revealed the following genotype constellation: G6-P[11]-I2-R2-C2-M2-A13-N2-T6-E2-H3. The VP1, VP2, VP3, VP6, NSP2 and NSP4 genes all belonged to DS-1-like genotype 2, but clustered more closely to bovine RVA strains than to lapine RVA strains. The NSP1 genotype A13 is typically associated with bovine RVAs, while the NSP3 genotype T6 and the NSP5 genotype H3 have been found in a wide variety of species. However, the isolated strain clustered within bovine(-like) T6 and H3 subclusters. Overall, the data indicate that the RVA strain is most closely related to bovine-like RVA strains and most likely represents a direct interspecies transmission from a cow to a rabbit. Altogether, these findings indicate that a RVA strain with an entirely bovine genome constellation was able to infect and spread in a laboratory rabbit colony., (Copyright © 2013 Elsevier B.V. All rights reserved.)

The family Picornaviridae contains well-known human pathogens (e.g., poliovirus, coxsackievirus, rhinovirus, and parechovirus). In addition, this family contains a number of viruses that infect animals, including members of the genus Cardiovirus such as Encephalomyocarditis virus (EMCV) and Theiler's murine encephalomyelits virus (TMEV). The latter are important murine pathogens that cause myocarditis, type 1 diabetes and chronic inflammation in the brains, mimicking multiple sclerosis. Recently, a new picornavirus was isolated from humans, named Saffold virus (SAFV). The virus is genetically related to Theiler's virus and classified as a new species in the genus Cardiovirus, which until the discovery of SAFV did not contain human viruses. By analogy with the rodent cardioviruses, SAFV may be a relevant new human pathogen. Thus far, SAFVs have sporadically been detected by molecular techniques in respiratory and fecal specimens, but the epidemiology and clinical significance remained unclear. Here we describe the first cultivated SAFV type 3 (SAFV-3) isolate, its growth characteristics, full-length sequence, and epidemiology. Unlike the previously isolated SAFV-1 and -2 viruses, SAFV-3 showed efficient growth in several cell lines with a clear cytopathic effect. The latter allowed us to conduct a large-scale serological survey by a virus-neutralization assay. This survey showed that infection by SAFV-3 occurs early in life (>75% positive at 24 months) and that the seroprevalence reaches >90% in older children and adults. Neutralizing antibodies were found in serum samples collected in several countries in Europe, Africa, and Asia. In conclusion, this study describes the first cultivated SAFV-3 isolate, its full-length sequence, and epidemiology. SAFV-3 is a highly common and widespread human virus causing infection in early childhood. This finding has important implications for understanding the impact of these ubiquitous viruses and their possible role in acute and/or chronic disease.

The efficacy of treatment in fetuses in whom congenital Toxoplasma gondii infection has ben established has been investigated using rhesus monkeys as a model for humans. A polymerase chain reaction has been developed for the detection of Toxoplasma gondii. Using this polymerase chain reaction congenital infection can be established within 2 days of receiving an amniotic fluid sample. The polymerase chain reaction has subsequently been used to monitor the effect of treatment on fetal infection. The results show that early treatment with the combination of pyrimethamine and sulfadiazine was clearly effective in reducing the number of parasites in the infected fetus. The parasite was no longer detectable in the amniotic fluid 10 to 13 days after treatment was started. Spiramycin, on the other hand, has to be administered for at least 3 weeks to achieve the same effect. Moreover, pharmacokinetic studies revealed that spiramycin does not reach the brain. Pyrimethamine and sulfadiazine are able to pass the blood-brain barrier. Pyrimethamine appears to accumulate in the brain tissue and reaches concentrations which are also effective in vitro.

The following metabolites of sulfadiazine (S) were isolated from monkey urine by preparative HPLC: 5-hydroxysulfadiazine (5OH), 4-hydroxysulfadiazine (4OH) and the glucuronide (5OHgluc) and sulfate conjugate of 5OH (5OHsulf). The compounds were identified by NMR, mass and infrared spectrometry and hydrolysis by beta-glucuronidase. The analysis of S, the hydroxymetabolites (4OH, 5OH) and conjugates N4-acetylsulfadiazine (N4), 5OHgluc and 5OHsulf in human and monkey plasma and urine samples was performed using reversed-phase gradient HPLC with UV detection. In plasma, S and N4 could be detected in high concentrations, whereas the other metabolites were present in only minute concentrations. In urine, S, the metabolites and conjugates were present. The limit of quantification of the compounds in plasma varies between 0.2 and 0.6 microgram/ml (S 0.31, N4 0.40, 4OH 0.20, 5OH 0.37, 5OHgluc 0.33 and 5OHsulf 0.57 microgram/ml). In urine it varies between 0.6 and 1.1 micrograms/ml (S 0.75, N4 0.80, 4OH 0.60, 5OH 0.80, 5OHgluc 0.80 and 5OHsulf 1.1 micrograms/ml). The method was applied to studies with healthy human subjects and Rhesus monkeys. The metabolites 5OH, 5OHgluc and 5OHsulf were present in Rhesus monkey and not in man. Preliminary results of studies of metabolism and pharmacokinetics in Rhesus monkey and man are presented.

This paper describes a rhesus monkey model to study congenital transmission and the prenatal diagnosis of Toxoplasma gondii infection. Transmission to the fetus was investigated after maternal infection in the second (Day 90) or third trimester (Day 130) of pregnancy. A parasitemia was induced and lasted for about 10 days as proven by mouse inoculation and nested PCR on whole blood samples and peripheral blood mononuclear cells. Transmission of T. gondii was proven in 4 of 9 (44%) fetuses in the second trimester and in 3 of 9 fetuses in the third trimester of gestation. Six of the 7 proven fetal infections could be diagnosed antenatally. Postnatally, 4 additional fetuses that most likely were congenitally infected were found, although this could not formally be proven. The mothers of these 4 fetuses were infected in the third trimester. If we accept this group as being antenatally infected, an overall transmission rate is found of 11 of 18 cases (61%). This rate is similar to that found in humans. This is the first description of a monkey model for congenital toxoplasmosis, that is suitable to study the approach of antenatal diagnosis and the effectivity of treatment, with obvious relevance for Toxoplasma infections in humans.