Resident resistance

Despite their severe and global cognitive impairments, some patients with Alzheimer's disease or vascular dementia continue to perform some complex mental activities skillfully. This paper briefly describes the artistic and game-playing skills of dementia patients, presents preliminary findings indicating that dementia patients with preserved skills exhibit slower cognitive deterioration than patients without retained cognitive skills, and illustrates how caregivers and other persons can utilize preserved abilities in the management of agitated and disruptive behavior.     

Masc2, a gene from Ascobolus encoding a protein with a DNA-methyltransferase activity in vitro, is dispensable for in vivo methylation

We have shown previously that masc1, a gene encoding a putative C5-DNA-methyltransferase (MTase), was necessary for the de novo 'Methylation Induced Premeiotically' (MIP) process and sexual reproduction in Ascobolus, whereas it was dispensable for maintenance methylation. A second MTase gene from Ascobolus, masc2, encodes a protein, Masc2, which possesses the large amino-terminal part characteristic of eukaryotic maintenance MTases. In vitro assays have shown that Masc2 displays a methylation activity, suggesting that it might be the MTase responsible for maintenance methylation. To check its function in vivo, we engineered a disruption of the masc2 gene. The resulting mutant strains did not exhibit any particular phenotype during either vegetative growth or sexual reproduction. Neither the masc2 mutation nor the double masc1 masc2 mutation had any detectable effect upon the maintenance of the pre-existing methylation of single gene copies previously subjected to MIP, natural retroelement-like repeats and tandemly repeated rDNA. The masc2 mutation did not alter either MIP or the other de novo methylation process that operates in vegetatives cells. Nor did it impair the meiotic process of methylation transfer. These results suggest that at least a third MTase gene responsible for maintenance and vegetative de novo methylation is present in Ascobolus.     

Signal transduction abnormalities in Alzheimer's disease: evidence of a pathogenic stimuli

Hippocampal and select cortical neuronal populations in Alzheimer's disease exhibit phenotypic changes characteristic of cells re-entering the cell division cycle. Therefore, in this study, we investigated whether components, known to trigger cellular proliferation and differentiation, upstream of the ras/mitogen-activated kinase pathway, could contribute to the activation of a signal transduction cascade in Alzheimer's disease. We found that proteins implicated in signal transduction from cell surface receptors via the ras pathway, namely Grb2 and SOS-1, were altered in cases of Alzheimer's disease in comparison to age-matched controls. SOS is increased in susceptible pyramidal neurons, while Grb2 shows more subtle alterations in subcellular distribution. Importantly, both SOS-1 and Grb2 show considerable overlap with early cytoskeletal abnormalities suggesting that the alteration in signal transduction molecules is a concurrent, if not preceding, event in the pathogenesis of Alzheimer's disease. Taken together with the cell cycle abnormalities previously reported, these findings suggest that a signal derived from the cell surface contributes to a stimulus for neurons in Alzheimer's disease to re-enter the cell cycle.     

Peripharyngeal space. Pathology

Tumors are the most frequent pathological pattern found in the peripharyngeal space. Topographically, intrinsic and extrinsic tumors can be distinguished. Intrinsic tumors are mostly salivary, nervous and vascular. Extrinsic tumors extend from the oral cavity, pharynx and parotid gland. MRI globally gives more impressive results than CT. Diagnosis of the tumor type often remains dubious in intrinsic tumors. CT-guided biopsy is then required.     

Hormonal suppressive therapy of thyroid nodules

In this article we report on a 43-year-old man, who had been treated with two cortisone injections containing soja bean oil for epicondylitis humeri radialis. Four weeks after the second injection necrotized fat which had been extracted surgically was sent to us for histological examination. We could show a calcifying collagen fibre necrosis being cleared by a granulomatous reaction and resorbed by granulation tissue. The calcifying necrosis of collagen fibres might have been induced by soja bean oil which were used as carrier of the drug.     

Haglund disease treated by simple resection of calcaneus tuberosity. An angular and therapeutic study. Apropos of 74 cases with 2 years follow-up

PURPOSE OF THE STUDY: The authors report the treatment of Haglund's disease, using a simple os calcis tuberosity resection. They reviewed long term results and the value of radiological criteria for pre-operative evaluation. MATERIAL: The series included 54 patients (74 feet) mostly female and young. The simple resection of os calcis tuberosity was performed without further operation or post-operative splint. METHODS: Post-operative results were appreciated according to 3 criteria: pain, functional activity and shoe wearing. Radiological criteria used Fowler and Philip angle, angle of calcaneal inclinaison, total angle, CL angle, Denis and Huber-Levernieux test and Heneghan and Pavlov parallel lines. Correlation tests with simple regression were used for statistical analysis. RESULTS: Results were graded as excellent and good in 73 per cent fair in 16.2 per cent and poor in 10.8 per cent cases. DISCUSSION: Results were compared to other series. Neither radiological criteria, angular or not, can rule out simple tuberosity resection, because results showed no relation between test and angle measurements. There is no correlation between post-operative radiographs and final result. The only efficient criteria of resection is the difference between Fowler and Philip, and CL angles. This technique may be recommended after few months of medical treatment, without using calcaneal osteotomies of Zadek type. CONCLUSION: The simple resection of os calcis tuberosity showed good results in 73 per cent cases at an average follow up of 6 years 9 months.     

Human plasma albumin transports [13C]docosahexaenoic acid in two lipid forms to blood cells

Docosahexaenoic acid (22:6) decreases blood platelet function and is highly concentrated in the brain where its depletion leads to functional impairments. Because the platelets and blood brain barrier capillary endothelium cannot hydrolyze the complex lipids for fatty acid (FA) uptake, nonesterified FA (NEFA) bound to albumin are assumed to be the delivery route of FA to these cells. The supply of 13C-labeled 22:6 to blood cells by plasma albumin was studied in humans after a single ingestion of this FA esterified in a triglyceride (TG). The 22:6 13C/12C ratio, measured by gas chromatography combustion-isotope ratio mass spectrometry was measured in lipid classes from albumin, platelets, leukocytes, and erythrocytes (taken as a tentative index of the brain uptake). Nonesterified [13C]22:6 bound to albumin was rapidly produced after ingestion, as a result of the hydrolysis of very low density lipoprotein (VLDL) plus chylomicron TG. We found that albumin carried another source of 22:6, lyso-phosphatidylcholines (lyso-PC), in which [13C]22:6 accumulated while the nonesterified [13C]22:6 reached its minimal plasma concentrations. Computation of the relative contribution of NEFA and lyso-PC for the [13C]22:6 delivery to platelets and erythrocytes showed that the [13C]22:6 supply to platelets occurred uniquely through NEFA, whereas this pool was weakly involved in the delivery to erythrocytes. In contrast, lyso-PC was uniquely concerned with the 22:6 delivery to erythrocytes and represented the major part of this supply. We conclude that plasma albumin carries 22:6 in two lipid forms that are involved differently in the delivery of this FA to target cells.     

Cellular levels of factor 390 and methanogenic enzymes during growth of Methanobacterium thermoautotrophicum deltaH

Methanobacterium thermoautotrophicum deltaH was grown in a fed-batch fermentor and in a chemostat under a variety of 80% hydrogen-20% CO2 gassing regimes. During growth or after the establishment of steady-state conditions, the cells were analyzed for the content of adenylylated coenzyme F420 (factor F390-A) and other methanogenic cofactors. In addition, cells collected from the chemostat were measured for methyl coenzyme M reductase isoenzyme (MCR I and MCR II) content as well as for specific activities of coenzyme F420-dependent and H2-dependent methylenetetrahydromethanopterin dehydrogenase (F420-MDH and H2-MDH, respectively), total (viologen-reducing) and coenzyme F420-reducing hydrogenase (FRH), factor F390 synthetase, and factor F390 hydrolase. The experiments were performed to investigate how the intracellular F390 concentrations changed with the growth conditions used and how the variations were related to changes in levels of enzymes that are known to be differentially expressed. The levels of factor F390 varied in a way that is consistently understood from the biochemical mechanisms underlying its synthesis and degradation. Moreover, a remarkable correlation was observed between expression levels of MCR I and II, F420-MDH, and H2-MDH and the cellular contents of the factor. These results suggest that factor F390 is a reporter compound for hydrogen limitation and may act as a response regulator of methanogenic metabolism.