Subarachnoid blood infusion versus raised intracranial pressure: Effects on the amino acid pattern in the extracellular fluid of the rabbit hippocampus

Abstract

In order to evaluate the role of a hemorrhage versus that of a transient increase in intracranial pressure in subarachnoid hemorrhage, the two components were induced separately in rabbits. Extracellular glutamate, sampled from the hippocampus with microdialysis, was used to evaluate the degree of CNS tissue damage. In four rabbits, autologous arterial blood was infused in the cisterna magna in a volume that would not affect the intracranial pressure. The other group of animals was infused with saline to elevate the intracranial pressure from 10 to > 100 mmHg. The increase of intracranial pressure per se did not induce significant changes in extracellular glutamate. However, 20-60 min after infusion of blood, a significant glutamate increase was recorded. Furthermore, aspartate, alanine, glycine and serine were also raised. The results indicate that blood in the subarachnoid space damages the brain primarily by inducing ischemia. Furthermore, the parameters employed gave no indication that an increase in intracranial pressure had a deleterious effect on CNS tissue. [Neurol Res 1999; 21: 404-408]     

Bone formation after sinus augmentation with engineered bone

Objectives: The aim of the following investigation was to quantify the resorption rate of tissue-engineered bone grafts in the maxillary sinus using volume measurements. MATERIAL AND METHODS: Sinus floor augmentation using autologous bone grafts from the iliac crest (n=17, group 1) was compared with commercially produced transplants of human cells seeded on polyglycolid-polylactid (PLGA) scaffolds (Oral Bone) (n=14, group 2). RESULTS: The total resorption rate for autologous transplants 3 months post operation was 29%, while the tissue-engineered bone showed a resorption rate of 90%. The autologous bone had a bone density of up to 266-551 Hounsfield units (HU), while sufficient mineralization of tissue-engineered bone was found in only one case (152 HU). CONCLUSION: In this clinical study, the use of autologous cancellous bone grafts in sinus augmentation was more reliable than scaffolds containing cultured osteoblasts. Further tissue-engineered bone transplants should be examined to draw general conclusions about the use of tissue-engineered grafts compared with autologous bone grafts for maxillary sinus augmentation.     

Immunochemical identification of novel high-molecular-weight protein isoforms of the adenomatous polyposis coli (APC) gene

Mapping analyses of monoclonal antibodies (MAbs) directed against the amino-terminus of the adenomatous polyposis coli (APC) gene product revealed that epitopes recognized by the MAbs FE9, CF11 and AC4 constitute different peptide sequences encoded by the APC exons 1, 2 and 3, respectively. The protein pattern detected with these specificity-defined immunoreagents, however, differed depending on the particular antibody used on Western blots of cellular urea extracts. APC exon 15-positive “classic” p300^apc polypeptide chains were identified by the MAb FE9, MAb CF11 and the C-terminus-specific MAb IEI, but only weak signals were obtained with the AC4 MAb, which defines an exon 3-encoded epitope. In contrast with this immunoreactivity, 2 novel high m.w. products of approx. 150/160 and 200 kDa were exclusively recognized by the AC4 MAb, which was shown to bind to the APC exon 3-encoded peptide sequence SRESTGYL. A molecular form of some 400 kDa was identified to represent a disulfide-bound oligomer of the p150/160^apc molecules. The novel APC-related molecules did not contain exon 1- and exon 15-encoded epitopes, as confirmed with the help of the FE9 and IE1 MAbs, respectively. This observation was corroborated by the fact that these novel proteins were not truncated in a collection of familial adenomatous polyposis patients with stop mutations in exon 15. We conclude, that APC MAb AC4-reactive p150/160 and p200 polypeptide chains represent novel genuine products of the APC gene devoid of exon 1- and exon 15-encoded protein interaction domains. © 1996 Wiley-Liss, Inc.     

Paediatric diagnostic reference levels for common radiological examinations using the European guidelines

Objective:The purpose of this study was to explore the feasibility to determine regional diagnostic reference levels (RDRLs) for paediatric conventional and CT examinations using the European guidelines and to compare RDRLs derived from weight and age groups, respectively.Methods:Data were collected from 31 hospitals in 4 countries, for 7 examination types for a total of 2978 patients. RDRLs were derived for each weight and age group, respectively, when the total number of patients exceeded 15.Results:It was possible to derive RDRLs for most, but not all, weight-based and age-based groups for the seven examinations. The result using weight-based and age-based groups differed substantially. The RDRLs were lower than or equal to the European and recently published national DRLs.Conclusion:It is feasible to derive RDRLs. However, a thorough review of the clinical indications and methodologies has to be performed previous to data collection. This study does not support the notion that DRLs derived using age and weight groups are exchangeable.Advances in knowledge:Paediatric DRLs should be derived using weight-based groups with access to the actual weight of the patients. DRLs developed using weight differ markedly from those developed with the use of age. There is still a need to harmonize the method to derive solid DRLs for paediatric radiological examinations.