Frequent Seizures Are Associated with a Network of Gray Matter Atrophy in Temporal Lobe Epilepsy with or without Hippocampal Sclerosis

Objective

Patients with temporal lobe epilepsy (TLE) with hippocampal sclerosis (HS) have diffuse subtle gray matter (GM) atrophy detectable by MRI quantification analyses. However, it is not clear whether the etiology and seizure frequency are associated with this atrophy. We aimed to evaluate the occurrence of GM atrophy and the influence of seizure frequency in patients with TLE and either normal MRI (TLE-NL) or MRI signs of HS (TLE-HS).

Methods

We evaluated a group of 172 consecutive patients with unilateral TLE-HS or TLE-NL as defined by hippocampal volumetry and signal quantification (122 TLE-HS and 50 TLE-NL) plus a group of 82 healthy individuals. Voxel-based morphometry was performed with VBM8/SPM8 in 3T MRIs. Patients with up to three complex partial seizures and no generalized tonic-clonic seizures in the previous year were considered to have infrequent seizures. Those who did not fulfill these criteria were considered to have frequent seizures.

Results

Patients with TLE-HS had more pronounced GM atrophy, including the ipsilateral mesial temporal structures, temporal lobe, bilateral thalami and pre/post-central gyri. Patients with TLE-NL had more subtle GM atrophy, including the ipsilateral orbitofrontal cortex, bilateral thalami and pre/post-central gyri. Both TLE-HS and TLE-NL showed increased GM volume in the contralateral pons. TLE-HS patients with frequent seizures had more pronounced GM atrophy in extra-temporal regions than TLE-HS with infrequent seizures. Patients with TLE-NL and infrequent seizures had no detectable GM atrophy. In both TLE-HS and TLE-NL, the duration of epilepsy correlated with GM atrophy in extra-hippocampal regions.

Conclusion

Although a diffuse network GM atrophy occurs in both TLE-HS and TLE-NL, this is strikingly more evident in TLE-HS and in patients with frequent seizures. These findings suggest that neocortical atrophy in TLE is related to the ongoing seizures and epilepsy duration, while thalamic atrophy is more probably related to the original epileptogenic process.     

Effects of double ligation of Stensen's duct on the rabbit parotid gland

Salivary gland duct ligation is an alternative to gland excision for treating sialorrhea or reducing salivary gland size prior to tumor excision. Duct ligation also is used as an approach to study salivary gland aging, regeneration, radiotherapy, sialolithiasis and sialadenitis. Reports conflict about the contribution of each salivary cell population to gland size reduction after ductal ligation. Certain cell populations, especially acini, reportedly undergo atrophy, apoptosis and proliferation during reduction of gland size. Acini also have been reported to de-differentiate into ducts. These contradictory results have been attributed to different animal or salivary gland models, or to methods of ligation. We report here a bilateral double ligature technique for rabbit parotid glands with histologic observations at 1, 7, 14, 30, 60 days after ligation. A large battery of special stains and immunohistochemical procedures was employed to define the cell populations. Four stages with overlapping features were observed that led to progressive shutdown of gland activities: 1) marked atrophy of the acinar cells occurred by 14 days, 2) response to and removal of the secretory material trapped in the acinar and ductal lumens mainly between 30 and 60 days, 3) reduction in the number of parenchymal (mostly acinar) cells by apoptosis that occurred mainly between 14–30 days, and 4) maintenance of steady-state at 60 days with a low rate of fluid, protein, and glycoprotein secretion, which greatly decreased the number of leukocytes engaged in the removal of the luminal contents. The main post- ligation characteristics were dilation of ductal and acinar lumens, massive transient infiltration of mostly heterophils (rabbit polymorphonuclear leukocytes), acinar atrophy, and apoptosis of both acinar and ductal cells. Proliferation was uncommon except in the larger ducts. By 30 days, the distribution of myoepithelial cells had spread from exclusively investing the intercalated ducts pre-ligation to surrounding a majority of the residual duct-like structures, many of which clearly were atrophic acini. Thus, both atrophy and apoptosis made major contributions to the post-ligation reduction in gland size. Structures also occurred with both ductal and acinar markers that suggested acini differentiating into ducts. Overall, the reaction to duct ligation proceeded at a considerably slower pace in the rabbit parotid glands than has been reported for the salivary glands of the rat.     

Biodiversity of 52 chicken populations assessed by microsatellite typing of DNA pools

In a project on the biodiversity of chickens funded by the European Commission (EC), eight laboratories collaborated to assess the genetic variation within and between 52 populations from a wide range of chicken types. Twenty-two di-nucleotide microsatellite markers were used to genotype DNA pools of 50 birds from each population. The polymorphism measures for the average, the least polymorphic population (inbred C line) and the most polymorphic population (Gallus gallus spadiceus) were, respectively, as follows: number of alleles per locus, per population: 3.5, 1.3 and 5.2; average gene diversity across markers: 0.47, 0.05 and 0.64; and proportion of polymorphic markers: 0.91, 0.25 and 1.0. These were in good agreement with the breeding history of the populations. For instance, unselected populations were found to be more polymorphic than selected breeds such as layers. Thus DNA pools are effective in the preliminary assessment of genetic variation of populations and markers. Mean genetic distance indicates the extent to which a given population shares its genetic diversity with that of the whole tested gene pool and is a useful criterion for conservation of diversity. The distribution of population-specific (private) alleles and the amount of genetic variation shared among populations supports the hypothesis that the red jungle fowl is the main progenitor of the domesticated chicken.     

Population density of the Réunion Grey White-eye Zosterops borbonicus within the summit ecosystems of Réunion,Mascarene Islands

Assessing population density is crucial for studying the ecology and evolutionary biology of species as well as for conservation purposes. Here we used point count methods to infer population density in a single-island endemic passerine bird, the Réunion Grey White-eye Zosterops borbonicus, that displays striking evidence of differentiation at a small spatial scale. Population density was estimated at 5.17 birds ha^?1 (CL 4.85–5.50), a value somewhat higher than previously believed. This estimation provides the first detailed estimation of bird population density in the vulnerable summit ecosystems of Réunion and will possibly allow a better understanding of the evolutionary causes of this plumage colour variation.     

Plasma neurotensin release and gastric emptying in the dumping syndrome

Seventy-three patients were studied after ingesting a liquid glucose meal, tagged with ¹¹³Indium. Nineteen of these patients were awaiting surgery for their duodenal ulcer, while 54 were studied postoperatively, 25 of whom experienced troublesome postprandial (dumping) symptoms in their daily lives. The radioactive marker emptied significantly faster in the symptomatic patients than in the symptomfree, pre and post-operative groups (initial emptying rate 3.45 ± 0.23, compared with 1.16 ± 0.19 and 1.27 ± 0.15% fall in counts/min respectively; p < 0.01). Initial (20 min) rises in the plasma concentrations of neurotensin-like immunoreactivity measured during the test correlated significantly with the rate of gastric emptying in all patients, being greatest in patients with dumping symptoms. Physiological concentrations of neurotensin have been shown to delay gastric emptying. The excessive rise in plasma neurotensin-like immunoreactivity in patients with dumping symptoms, presumably occuring as a result of the rapid passage of nutrients to the neurotensin-rich ileum, may possibly have a compensatory role in slowing further emptying from the stomach.     

Phycoerythrins of marine unicellular cyanobacteria. III. Sequence of a class II phycoerythrin

The genes for the alpha and beta subunits of a novel six bilin-bearing (class II) phycoerythrin were cloned from Synechococcus sp. WH8020 and sequenced. The cloned genes (mpeA and mpeB) were detected by homology with the genes for C-phycoerythrin from Pseudanabaena sp. PCC7409. The mpe locus occurs once in the genome and is arranged similarly to that of many other phycobiliproteins, with mpeA shortly 3' of mpeB. Sequence comparison suggests that this phycoerythrin (and perhaps all class II phycoerythrins) occupy a branch of the phycoerythrin family separate from five-chromophore per alpha beta (class I) phycoerythrins, C-phycoerythrin, and B-phycoerythrin. The position of the sixth chromophore of the class II phycoerythrin of WH8020 was determined by comparison of the amino acid sequence of the chromopeptides (Ong, L. J., and Glazer, A. N. (1991) J. Biol Chem. 266, 9515-9527) with the sequence deduced from the gene. This located the chromophore at residue 75 of the alpha subunit, very close to the alpha-83 chromophore in the primary structure and, presumably, in the three-dimensional structure.     

Phycoerythrins of marine unicellular cyanobacteria. II. Characterization of phycobiliproteins with unusually high phycourobilin content

A survey of marine unicellular cyanobacterial strains for phycobiliproteins with high phycourobilin (PUB) content led to a detailed investigation of Synechocystis sp. WH8501. The phycobiliproteins of this strain were purified and characterized with respect to their bilin composition and attachment sites. Amino-terminal sequences were determined for the alpha and beta subunits of the phycocyanin and the major and minor phycoerythrins. The amino acid sequences around the attachment sites of all bilin prosthetic groups of the phycocyanin and of the minor phycoerythrin were also determined. The phycocyanin from this strain carries a single PUB on the alpha subunit and two phycocyanobilins on the beta subunit. It is the only phycocyanin known to carry a PUB chromophore. The native protein, isolated in the (alpha beta)2 aggregation state, displays absorption maxima at 490 and 592 nm. Excitation at 470 nm, absorbed almost exclusively by PUB, leads to emission at 644 nm from phycocyanobilin. The major and minor phycoerythrins from strain WH8501 each carry five bilins per alpha beta unit, four PUBs and one phycoerythrobilin. Spectroscopic properties determine that the PUB groups function as energy donors to the sole phycoerythrobilin. Analysis of the bilin peptides unambiguously identifies the phycoerythrobilin at position beta-82 (residue numbering assigned by homology with B-phycoerythrin; Sidler, W., Kumpf, B., Suter, F., Klotz, A. V., Glazer, A. N., and Zuber, H. (1989) Biol. Chem. Hoppe-Seyler 370, 115-124) as the terminal energy acceptor in phycoerythrins.