Lymphocytocidal lymphocyte trapping by human lymph node cells: a tissue culture-ultrastructural study

An ultrastructural study was carried out on 25 lymphocyte-trapping cells selected from tissue cultures of human axillary lymph nodes. The trapping cells contained several hundred intravacuolar lymphocytes, most of which showed degenerative changes. The principal findings are: (a) a braod spectrum of lymphocyte degeneration; (b) a consistent pattern of lymphocyte degeneration beginning with perinuclear vacuoles and ending with breakdown of the nuclear envelope; (c) the viable lymphocytes tended to be located in a juxtanuclear region; (d) a lysosomal relationship was suggested for lymphocyte degeneration but not for lymphocyte trapping; and (e) degeneration of the trapping cell, or lymphocytes associated with other cells, was not observed. The sequence of degenerative changes differs from those reported for several classes of lymphocytocidal agents. There were no morphologic properties of the trapping cell which served to identify it more specifically. The findings, together with previous time-lapse film observations, warrant further investigation of the hypothesis that lymphocytocidal lymphocyte trapping may be involved in the control of lymphocyte populations.     

Strong and Auxiliary Forms of the Semi-Lagrangian Method for Incompressible Flows

We present a review of the semi-Lagrangian method for advection–diffusion and incompressible Navier–Stokes equations discretized with high-order methods. In particular, we compare the strong form where the departure points are computed directly via backwards integration with the auxiliary form where an auxiliary advection equation is solved instead; the latter is also referred to as Operator Integration Factor Splitting (OIFS) scheme. For intermediate size of time steps the auxiliary form is preferrable but for large time steps only the strong form is stable.     

Influence of glucagon replacement on the hyperglycemic and hyperketonemic response to prolonged somatostatin infusion in normal man

Somatostatin was infused for 6 h into seven normal subjects with and without a replacement dose of glucagon. The addition of glucagon to somatostatin resulted in a 30-40% rise in plasma glucagon, whereas plasma insulin declined by 40-50% in both treatment groups. Plasma glucose and glucose production initially increased 2-fold with glucagon replacement, and subsequently declined by 2-3 h to levels comparable to those observed with somatostatin alone. After 6 h plasma glucose and glucose kinetics were no different whether or not glucagon was present. The rise in blood ketones after somatostatin was not exaggerated by glucagon replacement. We conclude that glucagon lack is not a modifying factor in the late hyperglycemic and hyperketonemic response to prolonged infusions of somatostatin.     

Usefulness of molecular markers for detecting population bottlenecks via monitoring genetic change

It is important to detect population bottlenecks in threatened and managed species because bottlenecks can increase the risk of population extinction. Early detection is critical and can be facilitated by statistically powerful monitoring programs for detecting bottleneck-induced genetic change. We used Monte Carlo computer simulations to evaluate the power of the following tests for detecting genetic changes caused by a severe reduction in a population's effective size (Ne): a test for loss of heterozygosity, two tests for loss of alleles, two tests for change in the distribution of allele frequencies, and a test for small Ne based on variance in allele frequencies (the 'variance test'). The variance test was most powerful; it provided an 85% probability of detecting a bottleneck of size Ne = 10 when monitoring five microsatellite loci and sampling 30 individuals both before and one generation after the bottleneck. The variance test was almost 10-times more powerful than a commonly used test for loss of heterozygosity, and it allowed for detection of bottlenecks before 5% of a population's heterozygosity had been lost. The second most powerful tests were generally the tests for loss of alleles. However, these tests had reduced power for detecting genetic bottlenecks caused by skewed sex ratios. We provide guidelines for the number of loci and individuals needed to achieve high-power tests when monitoring via the variance test. We also illustrate how the variance test performs when monitoring loci that have widely different allele frequency distributions as observed in five wild populations of mountain sheep (Ovis canadensis).     

Validity of self-reported rheumatoid arthritis in elderly women

OBJECTIVE: To determine the validity of a self-reported physician diagnosis of rheumatoid arthritis (RA) in elderly women. METHODS: Women with self-reported RA were contacted and permission requested to contact their physician. Physicians were mailed a questionnaire requesting information on the subject's arthritic condition. Hand radiographs obtained at study entry were read for changes of RA. RESULTS: The self-reported diagnosis of RA could be confirmed in 26 (21%) individuals. CONCLUSION: The positive predictive value of self-reported RA was low in this cohort. Caution needs to be exercised in the use and interpretation of self-report data concerning arthritic conditions in epidemiologic studies.     

Estradiol is related to visual memory in healthy young men.

The influence of testosterone and estrogen on memory was investigated in 33 healthy young men. Tests of visual memory, visuospatial ability, verbal memory, and attention were administered, and circulating levels of estradiol and free testosterone were measured. Participants with high levels of estradiol performed better on 2 measures of visual memory than did those with normal but lower levels. There were no differences between individuals with high and low levels of testosterone on any cognitive measure. These results support the contention that estradiol influences memory in young men. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evidence of a thermally stable carbon-nitrogen deep level in carbon-doped,nitrogen-implanted,GaAs and AIGaAs

Nitrogen ion implantation is shown to form high resistivity regions (p_s ≥ 1 × 10¹⁰ Ω/) in C-doped GaAs and Al_0.35Ga_0.65As that remains compensated after a 900°C anneal. This is in contrast to oxygen or fluorine implantation in C-doped GaAs which both recover the initial conductivity after a sufficiently high temperature anneal (800°C for F and 900°C for O). In C-doped Al_0.35Ga_0.65As N- and O-implant isolation is thermally stable but F-implanted samples regain the initial conductivity after a 700°C anneal. A dose dependence is observed for the formation of thermally stable N-implant compensation for both the GaAs and AIGaAs samples. A C-N complex is suggested as the source of the compensating defect level for the N-implanted samples. Sheet resistance data vs anneal temperature and estimates of the depth of the defect levels are reported. This result will have application to heterojunction bipolar transistors and complementary heterostructure field effect transistor technologies that employ C-doped AIGaAs or GaAs layers along with high temperature post-implant isolation processing.