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.     

Malignant biliary hilar stenosis: MR cholangiography compared with direct cholangiography]

AIM: To assess the diagnostic value of three-dimensional (3D) magnetic resonance cholangiography (MRC) versus direct cholangiography such as endoscopic retrograde cholangiography (ERC) and percutaneous transhepatic cholangiography (PTC) in malignant biliary stenosis. MATERIAL AND METHODS: Twenty-nine patients (15 female and 14 male) (mean age 62 years) with malignant biliary strictures underwent MRC and ERC. Breath-hold 3D steady state free precession MR cholangiography was performed on a 1.5-T imager in the patients before ERC. In 25 patients findings at ERC/PTC were considered the standard of reference: 19 patients underwent ERC, 5 PCT and 1 both ERC and PTC due to unsuccessful papilla cannulation during the endoscopic examination. In the 4 remaining patients the surgical specimen was considered the standard of reference. In the 29 patients studied, histology performed during direct cholangiography and the examination of the surgical specimens demonstrated that the malignant hilar stenoses were caused by hilar cholangiocarcinoma (n=7), cholangiocarcinoma of the distal VBP (n=1), gallbladder cancers (n=6), endometrial metastasis (n=2), ovary metastasis (n=1), colon metastasis (n=1), breast metastasis (n=1). The correct identification of biliary stenosis and extension of the tumor (according to the Bismuth classification) by MR cholangiography and ERC were independently assessed by two readers blinded to each other's report. The results were compared. RESULTS: Identification of biliary stenosis and neoplastic extension were accurate in respectively 29/29 (100%) and 26/29 (89%) cases with MR cholangiography. The comparison of ERC/PTC and MRC images yielded the following results: Bismuth Type I (6 vs 6), Type II (5 vs 8), Type III (13 vs 10), Type IV (5 vs 5). Our results indicate that MR is less capable of identifying the extension of small lesions at the primary confluence of bile ducts than are ERC/PCT. DISCUSSION AND CONCLUSIONS: MR cholangiography is a non-invasive technique for biliary tract imaging. It does not require administration of contrast medium and allows complete visualisation of the biliary ducts. MR cholangiography allowed accurate diagnosis of malignant hilar stenosis providing equal information as direct cholangiography and may therefore obviate the need for ERC/PTC.     

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.     

Pancreas divisum and santorinicele: assessment by dynamic magnetic resonance cholangiopancreatography during secretin stimulation

PURPOSE: To evaluate the usefulness of MRCP, before and after secretin administration, in diagnosing Santoriniceles in patients with pancreas divisum. MATERIAL AND METHODS: One hundred and eight patients with suspected pancreatic disease, underwent dynamic magnetic resonance cholangiopancreatography (MRCP) before and after secretin administration (S-MRCP). S-MRCP images were evaluated for presence/absence of pancreas divisum, Santorinicele; size of the main pancreatic duct and of the Santorinicele. The onset of duodenal filling was calculated on dynamic S-MRCP images. S-MRCP findings were compared to endoscopic retrograde cholangiopancreatography (ERCP) ones (39/108). RESULTS: Pancreas divisum (PD) was detected in 6/108 patients (6%) at MRCP, and in 16/108 patients (14%) at S-MRCP. ERCP confirmed the diagnosis in 12/16 patients, with 1 false positive. 3 patients did not undergo ERCP. Santorinicele was detected in 4/108 (3%) patients at MRCP and in additional 4/108 (3%) patients at S-RMCP, only in patients with PD. Santoriniceles were confirmed in 7/8 patients at ERCP; in 1/8 patient CPRE was unsuccessful. The duct of Santorini was significantly larger (p< 0.05), in the pancreatic head, in patients with PD and Santorinicele (3.6 mm) compared to those with PD only (2.2 mm). A significant reduction in size of the pancreatic duct (26%) and of the Santorinicele (63%) was observed after sphincterotomy. The onset of duodenal filling was significantly delayed in patients with Santorinicele (2.1 vs 1.3 minutes)(p<0.05). CONCLUSIONS: S-MRCP helps to identify patients with pancreas divisum and Santorinicele, a known cause of impeded pancreatic outflow which benefits from endoscopic treatment.     

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.