Long-term synaptic plasticity in the honeybee

A monosynaptic response was recorded in vivo in the mushroom body of the bee brain, an important site for memory consolidation. Focal electrical stimulation of a major afferent input evoked an extracellular field potential that consisted of a presynaptic fiber volley and a postsynaptic response. We report a long-lasting potentiation of the synaptic response (2.6-fold increase; < or = 3.5 h). Potentiation of the response was induced by low-frequency stimulation (0.02-1.0 Hz), was input specific, and was maintained in the absence of stimulation. Paired-pulse facilitation of the response was converted to paired-pulse depression after potentiation, suggesting a presynaptic mechanism. This is the first demonstration of long-term synaptic plasticity in the insect brain.     

Polymorphism of pericentromere heterochromatin of polytene chromosomes of ovarian trophocytes in natural populations of the malaria mosquito Anopheles messeae Fall

The HBsAg status and demographic data of 2480 pregnant women who attended antenatal clinics at Maternal and Child Health Centres in Hong Kong were collected by means of a self-administered questionnaire over a 1-week period in July 1996, to explore the underlying reason of a higher than expected HBsAg prevalence. Local women constituted 49.2% of the sample, mainland Chinese 39.7% and others 11.1%. The overall HBsAg prevalence was 10.0%. When related to place of birth, those born in Hong Kong had a prevalence of 8.4% whereas the prevalence of those born in mainland China was 13.1% (P < 0.001). The overall HBsAg carriage rate is high because of a higher rate in immigrants in the community. It is apparent that the HBsAg prevalence of local people in Hong Kong has been decreasing in the past decade. Overall, the current HBsAg carriage rate in the local adult population is estimated to have declined to about 8%.     

Cortical variations of the dimension of correlation in children with attention deficit hyperactivity syndrome

INTRODUCTION AND OBJECTIVE: The syndrome of deficient attention and hyperactivity affects approximately 5% of children of school age. Clinically it is characterized by deficient attention, impulsiveness and excessive motor activity. Developments in nonlinear dynamic theory have made it possible to think of modelling cerebral activity as a dynamic system of chaotic type. One the most widely standardized measurements is the dimension of correlation (D2). In this paper we study the electroencephalographic traces of a control group of 9 healthy children and another group of 19 children with the syndrome of deficient attention, at rest and whilst carrying out a visuomotor task (Test of perception of differences). MATERIAL AND METHODS: The dimension of correlation was estimated for both groups. Statistical comparison was made between the cortical distributions of the D2 between both types of recordings and between both groups. RESULTS: The children with lack of attention showed a larger number of activated cortical areas than those of the control group when carrying out the same task. However, during the resting state there were no differences in the D2 between the control children and the children with deficient attention. The indicates that both groups have the same basal level of activation. CONCLUSION: The dimension of correlation is a method which permits the demonstration of an increase in neuronal activity in the stimulated areas, in this case in the occipital region.     

Vaginal-sigmoid fistula caused by diverticular disease

A case of a 66 years old patient suffering from a sigmoido-vaginal fistula and diverticulosis, previously treated with a total laparohysterectomy, is reported. Retrograde studies demonstrated the presence of fistula, whereas colonoscopy and barium enema failed. After laparotomy and an appropriate bowel preparation, surgery was restricted to the bowel resection and anastomosis, whereas the vaginal defect was not closed.     

Characterization of a negative cis-acting DNA element regulating the transcription of CYP2B1/B2 gene in rat liver

Polymeric films were deposited from hydroxyethylmethacrylate (HEMA) plasma on non-woven poly(butyleneterephtalate) (PBT) filter materials. To test the effect of deposition conditions on surface properties, film were deposited using a constant monomer flow rate and a discharge power ranging from 40-100 W. Surface composition and surface energetics were evaluated by Electron Spectroscopy for Chemical Analysis (ESCA) and contact angle measurement, respectively. Albumin (Alb) and fibrinogen (Fg) adsorption from single protein solutions to the plasma-coated filters was measured. Results illustrate the marked effects of the deposition condition on the surface composition, the surface field of forces, and the protein adsorption behavior. The latter is modeled by the application of the Good-van Oss-Chaudhury theory of Lewis acid-base contribution to interfacial energetics. Materials endowed with widely different properties are obtained from the same monomer and different deposition conditions, a result that must be taken into account both in the production step, to assure constant quality, and in the development of specifically tailored materials.     

Detection of skeletal metastases in Nigerian breast cancer patients: evaluation of radioisotope bone scan and radiography

Cerebellar granule cells isolated from postnatal day 7 mice, and cultured in minimal medium containing only insulin-like growth factor-I (IGF-I), both survive and differentiate. This differentiation is marked by neurite growth and expression of genes associated with terminal differentiation, the myocyte-specific enhancer factor 2A (MEF2A) and the alpha 6 subunit of the gamma-aminobutyric acidA receptor (GABAA alpha 6). Percoll gradient purified granule cells maintained without IGF-I, in minimal medium alone or in medium containing the antioxidant N-acetylcysteine (NAC), also express MEF2A and GABAA alpha 6. Thus, cultured granule neurons can differentiate to some extent cell-autonomously and IGF-I may not be a critical factor for this process.