Characterization of angiotensin peptides in plasma of anephric man.

Recent evidence suggests that a considerable proportion of plasma angiotensin is generated not in blood but in peripheral tissues. Through the measurement of angiotensin peptides and renin in the plasma of 11 anephric subjects, we have investigated whether kidney-derived renin, or some other tissue mechanism for angiotensin generation, is the major determinant of plasma angiotensin. Particular care was taken to prevent inadvertent activation of inactive renin and possible generation, conversion and metabolism of angiotensin peptides during processing of blood samples. Initial experiments revealed that plasma from anephric subjects contains high amounts of material which interferes in radioimmunoassays for angiotensin, even after high-performance liquid chromatography (HPLC). Therefore, in order to obtain an unambiguous identification of angiotensin peptides, a dual HPLC method was developed in which angiotensin peptides were first separated by HPLC, then acetylated and run again on HPLC before radioimmunoassay for angiotensin I and II (detection limits, 0.25 and 0.2 fmol/ml, respectively). The levels of angiotensin I and II were 1.2 +/- 1.6 and 0.7 +/- 0.5 fmol/ml (mean +/- s.d., n = 9-10), respectively, being 6% of levels in normal subjects, and were consistent with the active renin levels (1.8 +/- 1.7 muIU/ml, n = 11) which were 7% of levels in normal subjects. Artefactual activation of prorenin and angiotensin generation during sample processing were excluded as significant causes of the low levels of active renin and angiotensin I and II in anephric plasma. These data indicate that kidney-derived renin is the major determinant of angiotensin levels in normal human plasma. However, the present demonstration of low levels of active renin and angiotensin I and II in plasma of anephric subjects provides unequivocal evidence for a functional extrarenal renin-angiotensin system in man.     

Polyethylene Glycol Precipitates of Serum Contain a Large Proportion of Uncomplexed Immunoglobulins and C3

High pressure liquid chromatography (HPLC) was used to fractionate redissolved polyethylene glycol (PEG) precipitates isolated from the sera of normal volunteers and from patients with IgA nephropathy (IgAN) and systemic lupus erythematosus (SLE), 2 diseases characterized by elevated levels of circulating immune complexes. The individual fractions were analyzed by solid phase ELISA for IgA, IgM, C3, IgG, and complexes of IgG-IgA and IgG-C3. Although PEG precipitates were enriched for high molecular weight IgA and IgG (presumably bound within CIC), significant amounts of IgM, unbound IgG and C3 were also present. The quantities of the PEG-precipitable proteins did not correlate with their serum concentrations. IgG-IgA and IgG-C3 complexes were found in all precipitates examined, but the levels of complexes were higher in both patient groups. These results indicate that PEG precipitates a considerable quantity of proteins not bound in immune complexes. There appeared to be greater protein precipitation from sera of the patient groups compared to the amount precipitated from the normal sera. These results suggest that an understanding of the mechanism of PEG precipitation may be important in defining abnormalities in IgAN, SLE and perhaps other diseases characterized by elevated levels of CIC. In addition, the possibility of undetected CIC in PEG precipitable material must be considered.     

Meningiomas presenting with paranasal sinus involvement

Extracranial paranasal spread of meningiomas is uncommon. We describe the management of four cases, all of which first presented to an oto-rhino-laryngologist for an opinion. We suggest that greater use of modern imaging techniques could lead to earlier diagnosis. The natural history of extracranial spread is relatively benign but the management of regrowth of residual disease is difficult. We therefore suggest radical surgery in the first instance provided that the patients general health and configuration of the tumour allow.     

INFANTILE MYOFIBROMATOSIS WITH HEMANGIOPERICYTOMA-LIKE FEATURES OF THE TONGUE: A Case Study Including Ultrastructure

We report a case of an infantile myofibromatosis with hemangiopericytoma-like features arising in the tongue of a 5-month-old female infant. Many authors now classify neoplasms as infantile myofibromatosis that were previously called infantile hemangiopericytoma. The ultrastructural features of our tumor illustrate its biphasic nature and provide a possible explanation for its histogenesis. Infantile myofibromatosis, including those diagnosed as infantile hemangiopericytomas, rarely arise in any intraoral location. Despite the generally good prognosis associated with these neoplasms, complete surgical excision is recommended to avoid recurrences.     

Loss of Heterozygosity at the α-Inhibin Locus on Chromosome 2q Is Not a Feature of Human Granulosa Cell Tumors

The α-inhibin gene has been shown in knockout mouse models to be a suppressor of granulosa tumorigenesis in the mouse. To determine if α-inhibin has the same function in humans, we have assessed the frequency of loss of heterozygosity (LOH) of the α-inhibin gene locus on chromosome 2q in 17 human granulosa cell tumors and 36 epithelial ovarian cancers. LOH was detected in 12 of 36 (33.3%) epithelial tumors but in only 1 of 17 (6%) granulosa cell tumors. These data suggest that in contrast to the suggestions from the mouse model α-inhibin does not function as a granulosa cell tumor suppressor gene in the human. Furthermore, analysis of the TP53 gene in the granulosa cell tumors failed to detect either LOH or point mutations, indicating that they have a developmental pathway distinct from that of epithelial ovarian tumors.     

Rational sub-division of plant trypanosomes (Phytomonas spp.) based on minicircle conserved region analysis.

The sequences of minicircle conserved regions from various plant trypanosomatids have been determined and analyzed. The goal of this study was to add another tool to the arsenal of molecular probes for distinguishing between the different trypanosomatids occurring in plants: systemic trypanosomatids multiplying in the sap, those from the laticiferous tubes, and those developing in fruits, seeds or flowers but not in the plant itself and that are frequently considered as opportunistic insect trypanosomatids. As some plant intraphloemic trypanosomatids are the causative agents of important diseases, a clear definition of the different types of trypanosomatids is critical. The conserved region of the mitochondrial minicircle provides several specific features in a small sequence region containing three functionally elements required for minicircle replication. Trees generated from the analysis recapitulated trees drawn from analyses of isoenzymes, RAPD, and particular gene sequences, supporting the validity of the small region used in this work. Three groups of isolates were significant and in accordance with previous work. The peculiarity of phloem-restricted trypanosomatids associated with wilts of coconut and oil palm in Latin America - group H - is confirmed. In agreement with previous studies on their biological and serological properties the results highlighted this group called 'phloemicola'. It always differentiated from all other latex and fruit isolates or opportunistic trypanosomatids, like insect trypanosomatids. We can assert that phloemicola is the only well-defined taxon among all plant trypanosomatids. A group of non-pathogenic latex isolates from South American euphorbs (G), and a heterogenous group (A) including one fruit, one possible latex and one insect isolate are clearly distinct groups. The group of Mediterranean isolates from latex (D), even with a low boostrap, stood out well from other groups. The remainder of the isolates fell into a heterogeneous cluster. At least eight different groups in the plant trypanosomatids were identified.     

Motor map expansion following repeated cortical and limbic seizures is related to synaptic potentiation.

The effect of experimentally induced seizure activity on the functional reorganization of motor maps has not previously been investigated. Furthermore, while the functional reorganization of motor maps has been thought to involve increases in synaptic communication, there has yet to be a test of this hypothesis. Here we show that repeated seizure activity (kindling), that is accompanied by increased synaptic strength within adult rat motor cortex, results in a doubling of the caudal forelimb motor area. We measured neo-cortical evoked potentials in the right hemisphere prior to 25 days of electrical kindling of the medial frontal corpus callosum or amygdala and re-measured them either 1 or 21 days following the last kindling session. Then, using high resolution intracortical microstimulation (ICMS), the caudal forelimb area in the left hemisphere was mapped. This is the first report of any procedure causing a motor representation to double in size. Furthermore, this expansion was related to the enhanced area of a neocortical polysynaptic field potential and not the motor convulsions per se. Moreover, both the motor map and field potential enhancements were persistent in nature and could be driven from either cortical or limbic sites. The data have implications for human populations with epilepsy.