Placental Schistosoma haematobium infection in a German returnee from Malawi

Schistosomiasis is a widespread helminthic infection which sometimes may affect travelers to endemic areas. We report on a case of urogenital and placental schistosomiasis in a 28-year-old German woman who had been exposed to schistosomiasis in Lake Malawi one year earlier. She experienced painless macrohaematuria in her 21st week of pregnancy. Cystoscopy revealed vesical lesions typical for urogenital schistosomiasis. Histopathology confirmed ova of Schistosoma (S.) haematobium. The patient was treated with praziquantel 40 mg/kg/body weight/day for 3 days. After 285 days of gestation and 18 weeks post treatment, the patient delivered a healthy girl. Histopathology of placenta revealed eggs of S. haematobium in placental stroma. The infant proved negative for anti-Schistosoma spp. antibodies at the age of 15 months. This is the first report on placental schistosomiasis since 1980 and the first case occurring in a traveler.     

Encoding of nested levels of acoustic regularity in hierarchically organized areas of the human auditory cortex

Our auditory system is able to encode acoustic regularity of growing levels of complexity to model and predict incoming events. Recent evidence suggests that early indices of deviance detection in the time range of the middle‐latency responses (MLR) precede the mismatch negativity (MMN), a well‐established error response associated with deviance detection. While studies suggest that only the MMN, but not early deviance‐related MLR, underlie complex regularity levels, it is not clear whether these two mechanisms interplay during scene analysis by encoding nested levels of acoustic regularity, and whether neuronal sources underlying local and global deviations are hierarchically organized. We registered magnetoencephalographic evoked fields to rapidly presented four‐tone local sequences containing a frequency change. Temporally integrated local events, in turn, defined global regularities, which were infrequently violated by a tone repetition. A global magnetic mismatch negativity (MMNm) was obtained at 140–220 ms when breaking the global regularity, but no deviance‐related effects were shown in early latencies. Conversely, Nbm (45–55 ms) and Pbm (60–75 ms) deflections of the MLR, and an earlier MMNm response at 120–160 ms, responded to local violations. Distinct neuronal generators in the auditory cortex underlay the processing of local and global regularity violations, suggesting that nested levels of complexity of auditory object representations are represented in separated cortical areas. Our results suggest that the different processing stages and anatomical areas involved in the encoding of auditory representations, and the subsequent detection of its violations, are hierarchically organized in the human auditory cortex. Hum Brain Mapp 35:5701–5716, 2014. © 2014 Wiley Periodicals, Inc.     

Rhombencephalosynapsis as a cause of aqueductal stenosis: an under-recognized association in hydrocephalic children

Background

Rhombencephalosynapsis is a rare genetic aberration characterized by variable vermian hypoplasia/aplasia in conjunction with united cerebellar hemispheres. Genetic defects in the isthmic organizer at the mesencephalic–metencephalic junction are presumably responsible for the associated aqueductal stenosis.

Objective

We performed a retrospective review of 20 children with rhombencephalosynapsis to evaluate for and emphasize the association of aqueductal stenosis and hydrocephalus.

Materials and methods

We retrospectively reviewed the MR and CT images of 20 children (0–11 years old) with rhombencephalosynapsis encountered at two academic children’s hospitals. Rhombencephalosynapsis spectrum severity was graded based on pre-existing literature. We analyzed examinations for ventriculomegaly and degree of aqueductal stenosis. The collicular distances were measured from the collicular apices. Imaging studies were also analyzed for malformations of cortical and cerebellar development.

Results

Thirteen of the 20 children (65%) with rhombencephalosynapsis presented with clinical or imaging evidence of hydrocephalus and aqueductal stenosis, principally involving the caudal cerebral aqueduct. All children with aqueductal stenosis had collicular fusion. All six children with complete rhombencephalosynapsis had aqueductal stenosis. The cerebral aqueduct varied from normal to stenotic in children with incomplete rhombencephalosynapsis. Corpus callosum dysgenesis was present in four children.

Conclusion

Aqueductal stenosis in the setting of rhombencephalosynapsis is an under-recognized cause of noncommunicating hydrocephalus. Our findings support the hypothesis that a defect involving the common gene(s) responsible for the differentiation and development of both the roof plate and midline cerebellar primordium at the mesencephalon/first rhombomere junction may be responsible for the association of aqueductal stenosis and rhombencephalosynapsis.