Separate visual pathways for perception of actions and objects: evidence from a case of apperceptive agnosia

Recognition of different kinds of visual stimuli was studied ina patient who acquired apperceptive visual agnosia after a bilateraloccipitotemporal lesion which partially spared the primary visualcortex. Impairment in recognising static objects perceived visuallysharply contrasts with the relatively well preserved ability torecognise objects from gestures illustrating their use, and torecognise actions shown in line drawings. It is suggested that theoccipitoparieto-frontal pathway is involved in the recognition ofactions, and in the recognition of objects when sensorimotor experienceis evoked.

     

Herpesvirus, cytomegalovirus, human sperm and assisted fertilization

BACKGROUND: The effect of viral particles on the motility of human sperm and the relationship between sperm and virus are of importance particularly in assisted fertilization. METHODS: We incubated ejaculated sperm with or without seminal fluid with either herpes simplex virus type 2 (HSV2) or human cytomegalovirus (HCMV). For each experiment, 5 x 10(5) sperm were incubated with a viral load of between 10(4) and 10(6) plaque-forming units. RESULTS: We detected no apparent variations in the percentage of motile forms when sperm were incubated with either HSV2 or HCMV. Using a computer-aided semen analysis system, a slight difference was reported in the percentage of motile forms when seminal fluid-free sperm were incubated with HSV2 (57.18 versus 64.43 in the control). Although the mean amplitude of lateral head displacement and the curvilinear velocity were significantly higher in infected sperm, the difference in straight line velocity was not statistically significantly different. Few viral particles (HSV2 or HCMV) adhered to the sperm membrane in the presence of seminal fluid. However, more particles stuck when in the absence of seminal fluid, particularly with HSV2 (8% of sperm sections for HSV2; 4% for HCMV). CONCLUSIONS: The relationship between sperm and viruses depends on the type of virus present as well as the presence or absence of seminal fluid. Motility is not a good enough criterion on which to prove the presence of viral elements, either in the medium or on the sperm.     

IL-5 is essential for vaccine-induced protection and for resolution of primary infection in murine filariasis

The pathways conferring immunity to human filariases are not well known, in part because human-pathogenic filariae do not complete a full life cycle in laboratory mice. We have used the only fully permissive infection of mice with filariae, i.e., infection of BALB/c mice with the rodent filarial nematode Litomosoides sigmodontis. Our previous results showed that worm development is inversely correlated with Th2 cytokine production and eosinophilia. The scope of the present study was to directly elucidate the role of interleukin-5 (IL-5) and eosinophils in controlling the development of L. sigmodontis after vaccination and in primary infection. BALB/c mice immunized with irradiated third-stage larvae (L3) were confirmed to have elevated IL-5 levels as well as high subcutaneous eosinophilia and to attack and reduce incoming larvae within the first 2 days, resulting in 70% reduction of worm load. Treatment of vaccinated mice with anti-IL-5 antibody (TRFK-5) suppressed both blood and tissue eosinophilia and completely abolished protection. This demonstrates, for the first time in a fully permissive filarial infection, that IL-5 is essential for protection induced by irradiated L3 larvae. In contrast, in primary-infected mice, anti-IL-5 treatment did not modify filarial infection within the 1st month, most likely because during primary infection IL-5-dependent mechanisms such as subcutaneous eosinophilia are induced too late to disturb worm establishment. However, there is a role for IL-5 late in primary infection where neutrophil-dependent worm encapsulation is also under the control of IL-5. Received: 30 March 2000     

Novel FARS2 variants in patients with early onset encephalopathy with or without epilepsy associated with long survival

Mitochondrial translation is essential for the biogenesis of the mitochondrial oxidative phosphorylation system (OXPHOS) that synthesizes the bulk of ATP for the cell. Hypomorphic and loss-of-function variants in either mitochondrial DNA or in nuclear genes that encode mitochondrial translation factors can result in impaired OXPHOS biogenesis and mitochondrial diseases with variable clinical presentations. Compound heterozygous or homozygous missense and frameshift variants in the FARS2 gene, that encodes the mitochondrial phenylalanyl-tRNA synthetase, are commonly linked to either early-onset epileptic mitochondrial encephalopathy or spastic paraplegia. Here, we expand the genetic spectrum of FARS2-linked disease with three patients carrying novel compound heterozygous variants in the FARS2 gene and presenting with spastic tetraparesis, axial hypotonia and myoclonic epilepsy in two cases.Subject terms: Metabolic disorders, Mutation     

Effects of carotid sinus nerve transection on changes in neuropeptide Y and indolamines induced by long-term hypoxia in rats

 Long-term hypoxia induces changes in neuropeptide-Y-like immunoreactivity (NPY-LI) and/or in the content of serotonin (5-HT) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) at the central level. To determine whether these alterations depend on the integrity of carotid body (CB) chemoreceptors, intact rats or those whose carotid sinus nerve was transected (CSNT) were exposed to hypoxia (10% O₂) or to normoxia for 14 days. Thereafter, NPY-LI, 5-HT and 5-HIAA levels in discrete brain regions were determined. The increase in NPY-LI in the ventrolateral medulla oblongata (VLM) of intact hypoxic rats was mostly abolished after CSNT and therefore is mainly mediated by CB chemoreceptors. In contrast, other hypoxia-induced changes were similar or even enhanced in CSNT as compared to intact rats and therefore do not depend on the integrity of CB chemoreceptors. This was the case for the increase of NPY-LI in the striatum and the caudal dorsomedian medulla oblongata (DMM), as well as for all the changes in 5-HT and 5-HIAA in the DMM, the VLM, the raphe nuclei, the striatum and the frontal cortex. We propose that long-term hypoxia alters brain NPY-LI and indolamine content through the stimulation of CB chemoreceptors or ancillary chemoreceptors, as well as through local biochemical or morphological mechanisms. Received: 5 May 1998 / Received after revision: 27 July 1998 / Accepted: 3 September 1998     

Fecal Excretion of Mycobacterium leprae,Burkina Faso

Mycobacterium leprae was detected by optical microscopy, fluorescent in situ hybridization, and molecular detection in feces collected for the diagnosis of Entamoeba coli enteritis in a leprosy patient in Burkina Faso. This observation raises questions about the role of fecal excretion of M. leprae in the natural history and diagnosis of leprosy.