Molecular requirements for polyamines binding to the antispermine monoclonal antibody Spm8-2

Brain entropy and human intelligence: A resting-state fMRI study

Human intelligence comprises comprehension of and reasoning about an infinitely variable external environment. A brain capable of large variability in neural configurations, or states, will more easily understand and predict variable external events. Entropy measures the variety of configurations possible within a system, and recently the concept of brain entropy has been defined as the number of neural states a given brain can access. This study investigates the relationship between human intelligence and brain entropy, to determine whether neural variability as reflected in neuroimaging signals carries information about intellectual ability. We hypothesize that intelligence will be positively associated with entropy in a sample of 892 healthy adults, using resting-state fMRI. Intelligence is measured with the Shipley Vocabulary and WASI Matrix Reasoning tests. Brain entropy was positively associated with intelligence. This relation was most strongly observed in the prefrontal cortex, inferior temporal lobes, and cerebellum. This relationship between high brain entropy and high intelligence indicates an essential role for entropy in brain functioning. It demonstrates that access to variable neural states predicts complex behavioral performance, and specifically shows that entropy derived from neuroimaging signals at rest carries information about intellectual capacity. Future work in this area may elucidate the links between brain entropy in both resting and active states and various forms of intelligence. This insight has the potential to provide predictive information about adaptive behavior and to delineate the subdivisions and nature of intelligence based on entropic patterns.

Immunocytochemical demonstration of polyamines in nucleoli and nuclei

Although biochemical studies have shown that polyamines (PAs) occur in the nucleus, only few studies have examined the intranuclear distribution of these organic cations. By immunocytochemistry, we have previously demonstrated that PAs are located in ribosomes. We now show that PAs also are present in both nucleoli and nuclei of a variety of cell types. Detection of nucleolar and nuclear PAs required novel pretreatment procedures involving protease and/or DNase digestion of specimens prior to immunoreaction. Double fluorescence staining confirmed the localizations. This suggests that PAs may be important to the formation of ribosomes in nucleoli, as well as adds support to biochemical studies suggesting that PAs are involved in many biological events in the nucleus. Further biochemical studies will be needed to substantiate this hypothesis.

Immunocytochemical localization of polyamines during attachment and spreading of retinal pigment epithelial and intestinal epithelial cells

In order to form and maintain a protective barrier for photoreceptors, the retinal pigment epithelium relies on integrin signaling and related pathways to form adhesion complexes, undergo cell spreading, and establish a confluent cellular monolayer. Polyamines are multifunctional polycations that are essential for cell attachment and spreading, although their exact mechanisms of action are as yet unclear. We report new immunocytochemical evidence suggesting that in the cells of retinal pigment epithelium and also the intestinal epithelium, polyamines are present in a population of intracellular vesicles that appear transiently during initial stages of cell spreading. In newly attached cells with minimal spreading, the vesicles are seen near the nucleus, whereas in more highly spread cells, the vesicles are localized to the plasma membrane, near, but not precisely co-localized with an enzyme marker for adhesion complexes, focal adhesion kinase. We also observe pronounced nuclear staining in newly attached cells that have not spread, whereas this staining is decreased in cells that have spread. Nuclear staining has been previously reported in other cell types and has been attributed to DNA binding of polyamines, which is known to stabilize chromatin structure. We hypothesize that the appearance of polyamine vesicles near focal adhesions of cells undergoing attachment and spreading may reflect the mechanism by which polyamine pools are targeted to appropriate interaction sites necessary for the assembly of adhesion complexes. Alternatively, the vesicles could represent the mechanism by which polyamines are removed from the nucleus and possibly released from the cell.

Immunohistochemical analysis of tumor polyamines discriminates high-risk patients undergoing nephrectomy for renal cell carcinoma

Renal cell carcinoma (RCC) is known to display a wide variation in biological behavior and clinical outcome. Although usual bioclinical prognostic parameters (eg, nuclear grade, tumor stage) are to a certain extent useful in predicting the outcome of RCC after radical nephrectomy, they now appear to be insufficient. The polyamines (spermidine, spermine, and putrescine) are ubiquitous polycations that are essential for cell proliferation. To support their excessive proliferation, cancer cells have high rates of polyamine metabolism. Indeed, malignant cells typically have higher polyamine levels than their normal counterparts. Before this report, antipolyamine antibodies that are potentially valuable tools for the in situ observation of polyamines had not been exploited in clinical conditions. In the present study, tumor tissues obtained from radical nephrectomy performed for RCC (n = 73) were immunostained with the anti-spermine monoclonal antibody Spm8-2, and the immunoreactivity was evaluated as a prognostic tool. RCC cells displayed various reactivity to the antibody Spm8-2 that translated into a heterogeneous cytoplasmic staining. The prognostic value of the labeling index (LI) on clinical outcome was correlated with the usual clinicopathologic parameters, and the cell proliferation rate was evaluated using Ki-67 labeling. Multiple correspondence analysis and ascending hierarchical classification were performed to determine significant prognostic factors. Univariate statistical survival analysis demonstrated that tumor size (P < .001), nuclear grade (P < .01), necrosis (P < .007), tumor stage (P < .004), metastasis (P < .001), Ki-67 LI (P < .0003), and Spm8-2 immunoreactivity (P < .0001) were predictors of tumor-related death. A positive correlation was found between Ki-67 LI and Spm8-2 immunoreactivity (r' = .53). Multivariate analysis revealed that only Ki-67 LI and Spm8-2 immunoreactivity were significant independent factors in patients with metastases (P < .04 and <.001, respectively) and in patients without metastases (P < .006 and <.001, respectively). Moreover, 100% of the patients with Spm8-2 immunoreactivity <10% were alive at the end of the follow-up. In terms of predictive values, Spm8-2 immunoreactivity had the highest predictive values (sensitivity, 89; specificity, 75; risk ratio, 11) of all clinicopathologic parameters. This study demonstrates that the anti-spermine monoclonal antibody Spm8-2 may be used at the time of radical nephrectomy as a reliable prognostic marker for defining RCC patients at high risk for progression.

Reaction with, and fine structural recognition of polyamines by human IgE antibodies

Human IgE antibodies from nine allergic subjects were found to react with poly-L-lysine (PLL) and other polyamines. Radioimmunoassay inhibition studies indicated that the two amino groups, but not the carboxyl, in lysine contributed to the antibody binding and 4-aminomethyl-1,8-octanediamine, a compound containing three primary amino groups, was a better inhibitor than compounds containing only two primary amino groups. Ethylamine showed weak but clear inhibition indicating that even a single amino group could bind to the antibody combining site. Substituted ethanolamine and quaternary ammonium compounds were well recognized by some sera but with others, substitution hampered recognition. Inhibition studies with compounds containing an amino and a carboxyl group at different distances revealed that an adjacent carboxyl group interfered with recognition of the amino group by some IgE antibodies. IgE binding to PLL was examined at different pHs and ionic strengths. Binding was greatest at pH 5-6 to 8 and decreased markedly outside this range. Ionic strengths higher than 0.3 M significantly diminished the binding. These results indicated that binding of specific antibody to polyamine was due to electrostatic interactions of positively charged amino groups in the polyamine with the antibody combining site. These results may be relevant to mechanisms underlying recognition of some allergens in some atopic conditions.