Identification of Tumor Antigens in the HLA Peptidome of Patient-derived Xenograft Tumors in Mouse

1. Download : Download high-res image (147KB)
2. Download : Download full-size image

Highlights

• •Sufficient tumor tissues are often unavailable large HLA peptidome discovery.
• •Using patient derived xenograft (PDX) tumors can overcome this limitation.
• •The large PDX HLA peptidomes expand significantly those of the original biopsies.
• •The HLA peptidomes of the PDX tumors included many tumor antigens.

     

Genetically controlled differences in the effects of chlormequat on tetraploid wheat (Triticum turgidum)

Two crosses between Triticum turgidum wheat lines differing in their response to chlormequat (CCC) were tested. In the F₂ population of one cross, which was segregating for the Rht1 dwarfing allele, each plant was cloned by separation of two tillers, one of which was treated with CCC. The tall (rht1/rht1) and the intermediate (Rht1/rht1) genotypes showed a greater response to CCC than the semi-dwarf (Rht1/Rht1) genotype, as expressed by culm length and date of ear emergence. The F₃ families of another cross and their two semi-dwarf parents were grown in a three-replicated field test in paris of rows, one of which was treated with CCC. In one of the parents and in 1/4 of the F₃ families CCC induced a wide-angled tiller growth, suggesting a monogenic control of this growth habit in response to CCC.Based on an M.Sc. thesis presented by the senior author to the Faculty of Agriculture of The Hebrew University of Jerusalem.     

The relationship of calcium and parathyroid hormone in their effect on heart cells

Parathyroid hormone (PTH), the plasma concentration of which is raised in uremia, has been suggested as one of the agents responsible for the myocardial changes commonly seen in uremia. The effect of intact [1–84] PTH on rat heart cells grown in tissue culture has been studied. Addition of the hormone to the media significantly stimulated beating rate. The stimulation was directly proportional to the amount of PTH in the medium. Excessively high concentration of PTH caused immediate cessation of the beating, which was reversed by the addition of calcium to the medium. The extent of stimulation by PTH was inversely proportional to the calcium concentrations in the medium. Isoproterenol and phenylephrine at excessively high concentrations in the medium did not mimic the PTH effect either alone or together with PTH. When beating ceased due to verapamil the effect was not reversed by the addition of calcium to the medium.Calcium added to the myocytes seen after beating ceased reversed the effect and the cells started to beat again. Cells kept for a longer period in the arrested state were not revived by the addition of calcium.     

Hyperoxic exposure affects the ventilatory response to hypoxia in awake rats

We tested whether hyperbaric O2 (HBO) has an adverse effect on the hypoxic ventilatory drive. Four groups of rats were exposed for 550 min to O2 at 1.67, 1.90, and 2.15 ATA and to air at 1.90 ATA, respectively. Ventilatory parameters (frequency, tidal volume, and minute ventilation) were measured using whole-body plethysmography, before the hyperbaric exposure, immediately after the exposure, and up to 20 days after the exposure. Resting ventilation was not affected after exposure at 1.90 ATA to air or at 1.67 ATA to O2. HBO at 1.90 and 2.15 ATA caused a reduction of frequency and an elevation of tidal volume at different inspired gases: air, 5% CO2 balance O2, 80% O2, and 4.5% O2. However, minute ventilation on the day after the hyperoxic exposure was not different from the control at either air, 5% CO2, or 80% O2 but was markedly attenuated on the first three breaths at 4.5% O2. The hypoxic ventilation decreased to 48 +/- 13 (SD) and 32 + 11% after 1.90 and 2.15 ATA, respectively. The ventilatory parameters recovered in the days after HBO. We conclude that HBO reversibly depresses the hypoxic ventilatory drive, most probably by a direct effect on the carotid O2 chemoreceptors.     

Increased 5-Hydroxytryptamine and Norepinephrine Release from Rat Brain Slices by the Red Sea Flatfish

The effect of the Red Sea flatfish toxin pardaxin was examined on K+-evoked and on basal release of either [3H]norepinephrine or [3H]5-hydroxytryptamine from preloaded rat cortical slices. The K+-induced release of the neurotransmitters was stimulated in a dose-related manner at concentrations ranging from 0.5 to 4 micrograms/ml. Basal release of the two transmitters was elevated to a lesser extent. Although the stimulation of evoked release was approximately equivalent for the two neurotransmitters, the response to 5-hydroxytryptamine was reversible whereas that of norepinephrine was not washed by 20 min of superfusion. The mechanisms involved in producing these actions of pardaxin are not known; however, they may be mediated by changes in electrolyte fluxes across the neuronal membranes.     

Inhibition of Dopamine Agonist-Induced Phosphoinositide Hydrolysis by Concomitant Stimulation of Cyclic AMP Formation in Brain Slices

Abstract: We examined the effects of cyclic AMP on dopamine receptor-coupled activation of phosphoinositide hydrolysis in rat striatal slices. Forskolin, dibutyryl cyclic AMP, and the protein kinase A activator Sp -cyclic adenosine monophosphothioate ( Sp -cAMPS) significantly inhibited inositol phosphate formation stimulated by the dopamine D₁ receptor agonist SKF 38393. Conversely, the protein kinase A antagonist Rp -cyclic adenosine monophosphothioate ( Rp -cAMPS) dose-dependently potentiated the SKF 38393 effect. In the presence of 200 µ M Rp -cAMPS, the dose-response curves of the dopamine D₁ receptor agonists SKF 38393 and fenoldopam were shifted to the left and maximal agonist responses were markedly increased. The agonist EC₅₀ values, however, were not significantly altered by protein kinase A inhibition. Neither Sp -cAMPS nor Rp -cAMPS significantly affected basal inositol phosphate accumulation. These findings demonstrate that dopaminergic stimulation of phosphoinositide hydrolysis is inhibited by elevations in intracellular cyclic AMP. Dopamine receptor agonists that stimulate adenylyl cyclase could suppress their activation of phosphoinositide hydrolysis by concomitantly stimulating the formation of cyclic AMP in striatal tissue. The interaction between dopamine D₁ receptor-stimulated elevations in cyclic AMP and dopaminergic stimulation of inositol phosphate formation suggests a cellular colocalization of these dopamine-coupled transduction pathways in at least some cells of the rat striatum.     

CHARACTERIZATION OF TWO CHLORELLA VULGARIS (CHLOROPHYCEAE) STRAINS ISOLATED FROM WASTEWATER OXIDATION PONDS1

We report here on the characterization and isolation of two ecotypes of Chlorella vulgaris Beyerinck that coexist in wastewater reservoirs. One ecotype (C1) contains high amounts of chlorophyll b, is capable of autotrophic growth, and can utilize only a few organic solutes for growth. The second ecotype (C2) contains low amounts of chlorophyll b, requires vitamin B₁₂, and can support its growth with a broad range of organic compounds. Of the two ecotypes, the latter showed slower growth rates when light was the sole source of energy. Cells of C2-type Chlorella attained higher photosynthetic activities than C1-type cells at saturating irradiances. However, their low chlorophyll b content and lower light utilization efficiency suggest that C2-type Chlorella contains relatively low amounts of light-harvesting antennae, a disadvantage in severely light-limited ecosystems like wastewater reservoirs. We hypothesize that the two Chlorella types coexist by adopting different lifestyles: C1-type cells rely largely on their photosynthetic potential for energy conservation and growth, whereas C2-type cells may exploit their heterotrophic properties for this purpose.     

WT1 mutations in patients with Denys-Drash syndrome: a novel mutation in exon 8 and paternal allele origin

Denys-Drash syndrome (DDS) is characterized by early onset nephropathy, pseudohermaphroditism in males and a high risk for developing Wilms' tumour (WT). The exact cause of DDS is unknown but germline mutations in the Wilms' tumour suppressor gene (WT1) have recently been described in the majority of DDS patients studied. These mutations occur de novo and are clustered around the zinc finger (ZF) coding exons of the WT1 gene. Analysis of exons 2–10 of the WT1 gene in constitutional DNA from five patients with DDS was carried out using the polymerase chain reaction (PCR) and direct DNA sequencing. In four out of the five patients, heterozygous germline mutations were found: a novel point mutation in exon 8 (ZF₂) at codon 377 altering the wild-type histidine to arginine, and three previously described point mutations in exon 9 (ZF₃) in the codons corresponding to amino acids ³⁹⁴Arg and ³⁹⁶Asp. In one patient, no mutations could be demonstrated. In three patients where parental DNA was available, the mutations were shown to have occurred de novo. Furthermore, since tumour DNA in two of these cases had lost the wild-type allele, polymorphic markers from the short arm of chromosome 11 were used to determine the parental origin of the mutant chromosome. In both cases, the mutant chromosome was shown to be of paternal origin. Since the majority of published WT1 mutations in DDS patients alter a RsrII restriction site in exon 9, we were able to perform PCR-based diagnosis in a female patient with early renal insufficiency and normal external genitalia.     

Control of normal differentiation of myeloid leukemic cells. X. Glucose utilization,cellular ATP and associated membrane changes in D+ and D− cells

Glucose utilization, energy metabolism and associated membrane changes, have been studied in D⁺ myeloid leukemic cells that can be induced to undergo cell differentiation to mature granulocytes by incubation with the appropriate conditioned medium (CM) and in D^? myeloid leukemic cells that cannot be induced to differentiate to mature cells. Before incubation with CM, glycolysis and the glycolytic production of ATP were lower and the activity of the pentose cycle was higher in D⁺ than in D^? cells. ATP depletion induced a higher degree of agglutination by concanavalin A in D^? than in D⁺ cells, indicating a difference in their surface membrane. There were no detectable differences in the transport of glucose and the synthesis of sterols and fatty acids. After incubation with CM, the D⁺ cells, like normal granulocytes, showed a higher glycolysis, produced their ATP more through glycolysis than oxidative phosphorylation, became less dependent on the exogenous supply of glucose and oxygen and had a lower rate of sterol and fatty acid synthesis. The differentiating D⁺ cells also showed a change in their surface membrane resulting in an increased agglutinability without a change in ATP content and a stimulation of the pentose cycle by concanavalin A. These properties, which were not acquired by D^? cells, were found before most of the D⁺ cells had differentiated to mature granulocytes. The data indicate, that the block in the ability of the D^? cells to differentiate and the acquisition of the metabolic properties of normal granulocytes by differentiating D⁺ cells, were associated with differences in the organization of the cell surface membrane.