Cerebral net exchange of large neutral amino acids after lipopolysaccharide infusion in healthy humans

Introduction  

Alterations in circulating large neutral amino acids (LNAAs), leading to a decrease in the plasma ratio between branched-chain and aromatic amino acids (BCAA/AAA ratio), may be involved in sepsis-associated encephalopathy. We hypothesised that a decrease in the BCAA/AAA ratio occurs along with a net cerebral influx of the neurotoxic AAA phenylalanine in a human experimental model of systemic inflammation.     

Surgery for colorectal cancer in Greece

Objective The aim of this study is to analyse our experience and assess the outcome of surgery for colorectal cancer with curative intent in Greece.Methods During the last 10 years,550 patients were treated for colorectal cancer with curative intent.291(52.9%) of the patients suffered from colonic cancer while 259(47.1%) were operated for rectal cancer.Tumour site,Astler?Coller and TNM classifications and surgical procedures were recorded.Total mortality,morbidity and 5?year survival were evaluated.Results Morbidity rate was 12.0% and mortality rate was 0.68% for colonic cancer surgery,whereas the overall five year survival rate was 77.9%.Morbidity rate was 16.9% and mortality rate was of 0.38% for rectal cancer patients.The overall five year survival rate was 79.6%.Conclusion Morbidity,mortality rate and 5?year survival after colorectal surgery in our department in Greece are comparable to those published in the international literature.     

The east–west advancement flap (horizontal advancement flap) to repair a defect on the nose ala

Background The repair of an alar nasal defect is a frequent challenge for dermatologic surgeons for reasons of the high rate of non‐melanoma cancers in the area. Objective Our aim was to describe the use of an east–west cheek‐based flap (horizontal advancement flap) to repair a surgical defect on the nose ala. Methods Benefits and limits of this surgical procedure are evaluated. Result The resulting S‐shaped scar was well‐camouflaged among the natural skin lines (melolabial fold and melonasal junction). No architectural distortion of the nose resulted from the procedure. Conclusion In selected patients with small‐to‐medium‐size defects of the nasal ala, the horizontal advancement flap is a simple, reliable and aesthetic reconstruction option.     

Inhibitory control in children with attention-deficit/hyperactivity disorder: event-related potentials identify the processing component and timing of an impaired right-frontal response-inhibition mechanism.

BACKGROUND: A core deficit in inhibitory control may account for a wide range of dysfunctional behaviors in attention-deficit/hyperactivity disorder (ADHD). METHODS: Event-related potentials were measured in 10 children with ADHD and 10 healthy children during a task specifically involving response inhibition (Stop signal task). RESULTS: In response to all Stop signals, control participants produced a large negative wave at 200 msec (N200) over right inferior frontal cortex, which was markedly reduced in ADHD children. The N200 amplitude was significantly correlated across subjects with response-inhibition performance. In response to the Go stimuli, ADHD children showed a reduced slow positive wave (250-500 msec) in anticipation of failed inhibitions over right frontal scalp regions. CONCLUSIONS: ADHD children appear to have an abnormality in an early-latency, right inferior frontal processing component critical to the initiation of normal response-inhibition operations. They also appear to have a right frontal abnormality associated to the covert processing of Go stimuli preceding failed inhibitions. By providing timing and processing component specificity, these results extend the findings of recent functional MRI studies of inhibitory control reporting right frontal abnormalities in ADHD.     

Proteoglycans in human long-term bone marrow cultures: biochemical and ultrastructural analyses

Proteoglycans within the extracellular matrix of human bone marrow have been implicated in the process of hematopoiesis, but little is known about the structure and composition of these macromolecules in this tissue. Hematopoietically active human long-term bone marrow cultures were incubated with medium containing 35S-sulfate and 3H-glucosamine as labeling precursors. Proteoglycans present in the medium and cell layer were extracted with 4 mol/L guanidine HCI and purified by diethylaminoethyl (DEAE)-Sephacel ion exchange and molecular sieve chromatography. Both culture compartments contain a large chondroitin sulfate proteoglycan (MI, CI) that eluted in the void volume of a Sepharose CL-4B column and contained glycosaminoglycan chains of molecular weight (mol wt) approximately 38,000. A second population of sulfate-labeled material was identified as a broad heterogenous peak (MII, CII) that was included on Sepharose CL-4B at Kav = 0.31. This material when chromatographed on Sepharose CL-6B could be further separated into a void peak (MIIa, CIIa) and an included peak eluting at Kav = 0.39 (MIIb, CIIb). The void peaks (MIIa, CIIa) were susceptible to chondroitinase ABC digestion (99%) but slightly less susceptible to chondroitinase AC digestion (90%). Papain digestion of these peaks revealed them to be proteoglycans with glycosaminoglycan chains of mol wt approximately 38,000. The included peaks on Sepharose CL-6B (MIIb, CIIb) from both medium and cell layer compartments resisted digestion with papain, indicating the presence of glycosaminoglycan chains of mol wt approximately 38,000 either free or attached to a small peptide. Although this material was susceptible to chondroitinase ABC (98%), it was considerably less susceptible to chondrotinase AC (approximately 60%), indicating that it contained dermatan sulfate. A small amount of heparan sulfate proteoglycan was also identified but constituted only approximately 10% of the total sulfated proteoglycan extracted from these cultures. Additionally, approximately 40% of the incorporated 3H- activity radioactivity was present as hyaluronic acid. Electron microscopy revealed a layer of adherent cells covered by a mat containing ruthenium red-positive granules that were connected by thin filaments. The extracellular matrix layer above the adherent cells contained a mixture of hematopoietic cells. Chondroitinase ABC treatment of the cultures completely removed the ruthenium red-positive granules overlying the cells and resulted in a loss of approximately 70% of the 35S-sulfate-labeled material from the cell layer.(ABSTRACT TRUNCATED AT 400 WORDS)     

The occipitoparietal pathway of the macaque monkey: comparison of pyramidal cell morphology in layer III of functionally related cortical visual areas

The dendritic morphology of pyramidal cells located at the base of layer III in the primary visual area (V1), the second visual area (V2), the middle temporal area (MT), the ventral portion of the lateral intraparietal area (LIPv) and in the portion of cytoarchitectonic area 7a within the anterior bank of the superior temporal sulcus was revealed by injecting neurons with Lucifer Yellow in fixed, flattened slices of macaque monkey visual cortex. These areas correspond to different levels of the occipitoparietal cortical 'stream', which processes information related to motion and spatial relationships in the visual field. The tissue was immunocytochemically processed to obtain a light-stable diaminobenzidine reaction product, revealing the dendritic morphology in fine detail. Retrogradely labelled MT- projecting neurons in supragranular V1 (layer IIIc of Hassler's nomenclature, corresponding to Brodmann's layer IVb) were predominantly pyramidal, although many spiny multipolar (stellate) cells were also found. The average basal dendritic field area of pyramidal neurons in sublamina IIIc of V1 was significantly smaller than that in the homologous layer of V2, within the cytochrome oxidase-rich thick stripes. Furthermore, the average basal dendritic field areas of V1 and V2 pyramidal neurons were significantly smaller than those of neurons in MT, LIPv and area 7a. There was no difference in basal dendritic field area between layer III pyramidal neurons in areas MT, LIPv and 7a. While the shape of most basal dendritic fields was circularly symmetrical in the dimension tangential to the cortical layers, there were significant biases in complexity, with dendritic branches tending to cluster along particular axes. Sholl analysis revealed that the dendritic fields of neurons in areas MT, LIPv and 7a were significantly more complex (i.e. had a larger number of branches) than those of V1 or V2 neurons. Analysis of basal dendritic spine densities revealed regional variations along the dendrites, with peak densities being observed 40-130 microns from the cell body, depending on the visual area. The peak spine density of layer III pyramidal neurons in V1 was lower than that observed in V2, MT or LIPv, which were all similar. Pyramidal neurons in area 7a had the greatest peak spine density, which was on average 1.7 times that found in V1. Calculations based on the average spine density and number of dendritic branches at different distances from the cell body demonstrated a serial increase in the total number of basal dendritic spines per neuron at successive stations of the occipitoparietal pathway. Our observations, comparing dendritic fields of neurons in the homologous cortical layer at different levels of a physiologically defined 'stream', indicate changes in pyramidal cell morphology between functionally related areas. The relatively large, complex, spine-dense dendritic fields of layer III pyramidal cells in rostral areas of the occipitoparietal pathway allow these cells to sample a greater number of more diverse inputs in comparison with cells in 'lower' areas of the proposed hierarchy.