Treatment of l(2)mbn Drosophila tumorous blood cells with the steroid hormone ecdysone amplifies the inducibility of antimicrobial peptide gene expression

Insects rely on both humoral and cellular mechanisms to defend themselves against microbial infections. The humoral response involves synthesis of a battery of potent antimicrobial peptides by the fat body and, to a lesser extent, by blood cells. The cellular response on the other hand consists of phagocytosis of small microorganisms and melanization and encapsulation of larger parasites. The l(2)mbn cell line, established from tumorous larval hemocytes, represents a system of choice to dissect the molecular events controlling cellular immunity. We report here that l(2)mbn cells can be efficiently induced to differentiate in adherent, macrophage-like cells by treatment with 20-hydroxyecdysone. Ecdysone treatment increases both the phagocytic capacity of l(2)mbn cells and their competence to express antimicrobial genes in response to immune challenge. We also report that expression of several regulatory molecules thought to be involved in the immune response is up-regulated by ecdysone in l(2)mbn cells.     

The other side of the bed

BACKGROUND: Despite being one of the world's most common neoplasias, there is little information on the molecular events that lead to gastric cancer. Molecular studies have shown that inactivation of tumor suppressor genes by mutation and/or allelic loss is an important genetic alteration in the multistep process of tumorigenesis. METHODS: In an attempt to identify a putative tumor suppressor gene involved in the carcinogenesis of gastric cancer, we performed Southern blot analysis using the tpr probe for 44 patients with gastric cancer, using tumor tissue and normal tissue from the same specimen. RESULTS: Of the 44 samples, 7 (16%) were informative, heterozygous cases for the tpr probe. Three of the informative cases showed a loss of heterozygosity and 3 cases showed homozygous deletion for the tpr probe (6 of 7; 85%). CONCLUSIONS: These findings suggest that tpr gene plays a role in gastric tumorigenesis, and this may be due to a tumor suppressor effect for the tpr gene.     

Neural tube defects in chromosomally normal and abnormal human embryos

Neural tube defects (NTDs) were recognized in eight out of 91 intact embryos from spontaneous abortions and in one case of an induced abortion following prenatal diagnosis of a chromosomal disorder. Five of the nine cases showed chromosomal abnormalities. Trisomy 18 and triploidy were associated with spina bifida in three cases, trisomy 7 with parieto-occipital encephalocele and monosomy X with spina bifida and iniencephaly in one case. A sixth anencephalic embryo in which chromosomal analysis was not performed showed a malformation pattern highly suggestive for trisomy 18. Discussion focuses on the high rate and the type of chromosomal abnormalities among spontaneously aborted NTD embryos, on the contrasting phenotype of 45,X conceptions and on the morphogenesis of the different neural tube defects in early development. In view of future early endovaginal ultrasound diagnosis, the changing morphological pattern is exemplified, and ranges from apparently hyperplastic to degenerative alterations of the exposed neural tissue.     

Characterization of the Saccharomyces cerevisiae cdc42-1ts allele and new temperature-conditional-lethal cdc42 alleles

The administration of neurotrophins affects neuronal survival and growth, but less is known about their ability to modify the expression of growth associated genes following injury to CNS neurons. Here we characterize the effect of brain-derived neurotrophic factor (BDNF) on mRNA levels for T alpha1 alpha-tubulin, and for GAP-43, two genes whose expression levels in retinal ganglion cells (RGC) tend to correlate with growth. We first determined that most adult rat RGCs can retrogradely transport BDNF by injecting 125I-BDNF into RGC target sites in vivo. We then used quantitative in situ hybridization to characterize the effect of axotomy, or axotomy and BDNF administration on mRNA levels for GAP-43 and T alpha1. Axotomy alone resulted in a general decrease in T alpha1 alpha-tubulin mRNA levels by 2 weeks, and elicited an increase in GAP-43 mRNA levels in an average of 30% of surviving RGCs. The intravitreal administration of a single dose of BDNF (5 microg) to axotomized RGCs on the day of injury did not affect T alpha1 alpha-tubulin mRNA levels, but was followed by a moderate (approximately 80%), and short-lasting enhancement of GAP-43 mRNA levels in most RGCs during the first week after axotomy. No significant increase in GAP-43 mRNA levels was observed when BDNF was injected into the uninjured eye. We conclude that BDNF specifically enhances GAP-43 but not T alpha1 mRNA levels in injured RGCs. Because BDNF is known to stimulate branch length of injured RGCs, we suggest that changes in the expression of GAP-43, but not T alpha1 tubulin, correlate with branching of injured neurons as opposed to long distance regrowth.     

Anisotropy of human muscle via non-invasive impedance measurements

Combining non-invasive 50 kHz impedance measurements with a mathematical model for the underlying structure, we obtain in vivo values for the transverse and longitudinal conductivities of the muscles of the human thigh and for the (isotropic) conductivity of the covering skin-fat layer. Results for a healthy male subject are in acceptably good agreement with those obtained elsewhere on surgically exposed or freshly excised animal tissue and with 'global' measurements on humans. Also, measurements using rotatable probes reveal orientations of underlying muscle fibres via minima in resistance versus angle curves. The results suggest potentially useful methods for studying muscle properties in clinical and physiological research.     

Orthopaedic surgery in hemophilic patients with human immunodeficiency virus

Patients registered at the author's hemophilia center between 1982 and 1994 were studied to establish whether major orthopaedic surgical procedures accelerate the fall of CD4 lymphocyte counts of patients with hemophilia who are infected with the human immunodeficiency virus, and whether patients who had surgery had different rates of development of acquired immune deficiency syndrome or death when compared with patients who did not have surgery. The patients were divided into four groups: Group 1, 22 patients who were human immunodeficiency virus positive undergoing orthopaedic surgery; Group 2, 89 patients who were human immunodeficiency virus positive not undergoing orthopaedic surgery; Group 3, 18 patients who were human immunodeficiency virus negative undergoing orthopaedic surgery; and Group 4, 135 patients who were human immunodeficiency virus negative not undergoing orthopaedic surgery. There was no significant difference between the rates of decline of CD4 lymphocyte counts for patients who were human immunodeficiency virus positive who underwent surgery when compared with human immunodeficiency virus positive patients who did not undergo surgery, nor was there any significant difference between the two human immunodeficiency virus negative groups. There were no significant differences in the rate of development of acquired immune deficiency syndrome or mortality rates between patients who had surgery and those who did not.     

A case of fungal keratitis: A clinical and in vivo confocal microscopy assessment

A presumed case of fungal keratitis is presented. Confocal images highlight the advantage of using such technology to follow therapeutic progress, particularly when standard laboratory testing is inconclusive. This case also demonstrates the importance of continued patient education regarding overall compliance and lens care.     

Deformation characteristics and stress–strain response of nanotwinned copper via molecular dynamics simulation

In this research parallel molecular dynamics (MD) simulations have been performed to study the deformation behavior of nanocrystalline copper samples with embedded nanotwins under approximately uniaxial tensile load. Simulation results reveal that twin boundaries (TBs) act as obstacles to dislocation movements that lead to the strengthening of nanotwinned structures. However, easy glide of dislocations parallel to the TBs contribute primarily to the plastic strain or ductility of these materials. At higher deformation stages, the strengthening effects reach a maximum when abundant dislocations begin crossing the TBs. Due to this highly anisotropic plastic response of the grains, a random polycrystalline sample will show combined properties of ductility and strength. The strengths of the nanotwinned models are found to exhibit an inverse relationship with the twin width and temperature. We also investigate the relation between the deformation behavior in different grains, their orientation with respect to the loading direction, and ultimately the observed response of nanotwinned structures.