The effects of X monosomy on brain development: Monozygotic twins discorcant for Turner's syndrome

Monosomy for the X chromosome is the most frequent cause of Turner's syndrome, a common clinical syndrome associated with particular physical and neurobehavioral features. The results from comprehensive assessment of prepubertal monozygotic female twins discordant for X monosomy are presented. Zygosity was established with DNA Fingerprinting and no evidence of chromosomal mosaicism was seen in either child. Physical features in the affected twin were relatively mild with respect to the full spectrum of physical malformations and disabilities associated with Turner's syndrome. The neurobehavioral phenotypes of the twins were compared. Although both sisters scored in the superior range of intelligence, the affected twin's Performance IQ was 18 points less than her sister, whereas Verbal IQ showed only a 3-point difference between the sisters. Other relative differences were noted within the executive, visuospatial, and visuomotor domains of function. Behavioral evaluation indicated greater problems with attention, hyperactivity, and anxiety in the affected twin. Quantitative analysis of brain anatomy revealed evidence of both general and regional effects of X monosomy on neurodevelopment. Cerebrospinal fluid volume was increased by 25% in the affected twin compared with her sister with a corresponding decrease in gray matter volume. The right frontal, right parietal–occipital, and left parietal-perisylvian regions showed the greatest discrepancy between the sisters with respect to increased cerebrospinal fluid and decreased gray matter volumes in the twin with X monosomy. Differences in the posterior fossa were also noted with a 50% relative increase in the volumes of the fourth ventricle and cisterna magna and a 10 to 15% relative reduction in size of the cerebellar vermis, pons, and medulla in the affected twin. The association between the neurobehavioral and neuroanatomical findings in the affected twin is discussed. The unique nature of the naturally occurring genetic phenomenon seen in this twin pair provides an opportunity to more fully elucidate the neurobehavioral phenotype associated with X monosomy and Turner's syndrome.     

Crystalloids, colloids and kids: a review of paediatric burns in intensive care

This is a retrospective review of all burns patients admitted to a paediatric intensive care unit (PICU) over a 7 year period. Resuscitation fluid therapy and clinical course are presented. Ninety-eight new burns victims were admitted with a mortality rate of 10.2%, all in burns of greater than 25% body surface area (BSA). The incidence of ARDS was 20%, with an 18% mortality rate. Of 85 patients with burns greater than 5% BSA, 33 received the hospital-recommended colloid-based resuscitation formula, 46 received a combination of crystalloids and colloids and in 6 patients the resuscitation regimen was not able to be determined. The aetiology, age distribution, sex ratio, severity of burns and length of stay in hospital did not alter significantly over the study period. The number of burns admissions to PICU increased, as did their duration of intubation and ICU stay. The hospital-recommended resuscitation formula consistently underestimated the fluid volume required for adequate resuscitation. No statistically significant difference in adverse effects was found between the resuscitation groups. This study is unable to recommend a definitive approach to the fluid resuscitation of burns shock in paediatrics and the best approach is one of meticulous fluid resuscitation titrated on clinical effect.     

Amoebae free-living. Report of the first Italian case of myelitis.

The AA. refer on the first Italian case of amoebae "Limax" primitive myelitis in a 25-year-old man. Microscopical observation showed amoebae free-living, but their cultivation and identification were not possible. The patient recovered because of the propriety of diagnosis and therapy with amphotericin B.     

Biological monitoring of toxic metals in urine by simultaneous inductively coupled plasma-atomic emission spectrometry

A simple and rapid method for the simultaneous determination of 11 metals (As, Be, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, and Zn) in urine by inductively coupled argon plasma-atomic emission spectrometry is presented. Acidification of the urine was the only sample preparation required. Background correction was applied to ensure accuracy. Analytical calibration was based on matrix matching using a "simulated urine" solution. Detection limits in the low mg/L range and linearity over three orders of magnitude were obtained for all 11 metals. In the Occupational Health Laboratory, this procedure has been applied for routine screening of workers for occupational exposure to toxic metals.     

The Sesto Fiorentino study: point and one-year prevalences of psychiatric disorders in an Italian community sample using clinical interviewers

BACKGROUND: It has been argued that lay interviewers' use of fully-structured interviews could lead to a diagnostic pattern different to that by treating physicians. Clinical interviewers in community samples should probably identify cases that are closer to those seen in clinical settings. The greatest advantage of using clinical interviewers consists of the immediate assessment of a possible psychopathology, i.e. the evaluation of current disorders. METHODS: Two thousand three hundred and sixty-three citizens from the community of Sesto Fiorentino, Italy, were interviewed by their own general practitioners using the Mini International Neuropsychiatric Interview (MINI). Positive cases for any lifetime psychiatric disorder as well as a random sample of the negative cases were re-interviewed by psychiatrists or trained residents in psychiatry using the Florence Psychiatric Interview (FPI). RESULTS: The point prevalence for any current disorder was 8.7%; the two disorders with the highest prevalence were generalised anxiety disorder (2.9%) and major depressive episode (2.7%). The figures increase about 50% when the sub-threshold sequelae of previous disorders are considered. Current comorbidity was generally high. The one-year prevalence of any disorder was 10.6%. Ninety-two percent of the cases sought help, 82% were being treated at the moment of interview. Social impairment was considerable. CONCLUSIONS: The period prevalence rates for most of the disorders considered were generally comparable with the range defined by previous studies conducted in other Western countries, despite using different methodologies. Conversely, the use of health facilities, the treatment received and the social impairment were much higher than those reported by the other studies, suggesting a greater similarity with the clinical samples.     

Impaired conditioned taste aversion learning in APP transgenic mice

Cognition in transgenic mouse models of Alzheimer's disease (AD) has been predominantly characterized in explicit spatial orientation tasks. However, dementia in AD encompasses also implicit memory systems. In the present study a line of transgenic mice (TgCRND8) encoding a double mutated allele of the human amyloid precursor protein (APP) genes was evaluated in an implicit associative learning task of conditioned taste aversion (CTA). CTA is a form of Pavlovian classical conditioning, in which a mouse learns to avoid a novel taste of saccharine (conditioned stimulus) paired with an experimentally induced (systemic injection of lithium chloride) nausea (unconditioned stimulus). In contrast to conditioned non-Tg mice, TgCRND8 APP mice developed weaker aversion against saccharine and quickly increased its consumption in repeated tests. These results indicate that TgCRND8 mice show a significant impairment not only in explicit spatial memory, as has been previously shown [Nature 408 (2000) 979], but also in implicit memory. Control experiments confirmed that TgCRND8 and non-Tg mice had comparable taste sensitivities in response to appetitive as well as aversive tastes. The study suggests that the CTA paradigm can be a sensitive tool to evaluate deficits in implicit associative learning in APP transgenic mouse models of AD.     

Evaluation of a Diagnostic Algorithm Using Immunoglobulin M Enzyme-Linked Immunosorbent Assay To Differentiate Human West Nile Virus and St. Louis Encephalitis Virus Infections during the 2002 West Nile Virus Epidemic in the United States

A diagnostic algorithm was developed to differentiate between human infections of West Nile virus (WNV) and St. Louis encephalitis virus (SLEV) using positive-to-negative (P/N) ratios derived from the immunoglobulin M capture enzyme-linked immunosorbent assay (MAC-ELISA). To validate this algorithm, we tested 1,418 serum and cerebrospinal fluid (CSF) samples from confirmed WNV and SLEV infections collected during the WNV epidemic of 2002 in the United States. WNV P/N-to-SLEV P/N ratios (W/S ratios) were calculated and used to identify the infecting virus. These results were compared to results from the plaque reduction neutralization test (PRNT), which is currently the standard assay used to discriminate between closely related flavivirus infections. If the W/S ratio was ≥1, the predictive value positive (PNP) for WNV was 97.8%, where 95% of flavivirus cases were due to WNV infection and only 3.7% of specimens would require PRNT to differentiate WNV from SLEV infection. Use of the W/S ratio as part of the testing algorithm to interpret MAC-ELISA results generates reportable probable cases quickly, alleviating the need for PRNT in most instances.     

Mouse Sperm Rosette: Assembling During Epididymal Transit,in vitro Disassemble,and Oligosaccharide Participation in the Linkage Material

In many mammals, sperm associations had been observed, but not in the mouse. In this work, mouse sperm rosettes are morphologically described inside the epididymis and during its dissolution in a culture medium. Also characterized are the saccharides present in the linking material. Sperm association and other epididymal actions are supported by sperm during epididymal transit and are verified at the caudal region, suggesting a relation between epididymal transit and sperm maturation. In drops of epididymal content obtained from distal (cauda), but not from proximal (caput and corpus) regions; dissolved in culture medium, rosettes appear to be 10 to 15 motile sperm joined by their heads. After 3 min, sperm progressively detach, disassembling the rosette. These structures are studied by several techniques, including optic, electronic (scanning electron microscopy and transmission electron microscopy), and video microscopy. At the ultrastructural level, a dense network of electron‐dense material was observed between sperm heads, joining them. Based on previous works in rat, several lectins were used to characterize the type of saccharides present in this linking material. To avoid the contact between sperm and epididymal fluid from distal region—that probably exerts an influence on sperm association—a ligature was placed between caput and corpus. This epididymal content isolated from caput did not display any rosettes after 28 days. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc.     

Thymic stromal cell specialization and the T-cell receptor repertoire

Ten years ago, we proposed a model for thymus function in which thymic epithelial cells are primarily responsible for imprinting major histocompatibility complex (MHC)-restricted specificity, and bone marrow-derived macrophages or dendritic cells are responsible for the induction of self-tolerance. Since then, transgenic and knockout models have allowed for a dissection of thymic stromal components in vivo, leading to a new understanding of their specialized functions. We have determined that with regard to class II-restricted CD4 T-cell development, two distinct subsets of thymic epithelium help shape the repertoire: Cortical epithelium appears solely responsible for positive selection, whereas a fucose-bearing subset of medullary epithelium is specialized for negative selection. This absolute separation of positive and negative selection into two distinct spatial and temporal compartments leads to a much simpler view of the process of repertoire selection. Finally, a novel view of the function of the thymic medulla is discussed.