Effects of peptides and steroid hormones on cell kinetic parameters of normal human breast tissue in organ culture

Summary Several studies have shown the importance of different hormones in the regulation of mammary tsssue growth. The use of organ culture techniques has shown tremendous value for the knowledge of cell proliferation in human breast tissue. Therefore, the purpose of these studies was to analyze the length of the cell cycle, DNA-labeling index, mitotic index, and growth fraction under the effects of insulin, hydrocortisone, and 17-β estradiol in 5-d organ culture. Normal tissues obtained from patients who underwent breast surgery for benign lesions were individually cultured at 37°C (95% air:5% CO₂ in Medium 199). Autoradiographic studies indicated that the hormones shortened the length of cell cycle of normal breast tissue in 5-d organ cultures. From the growth fraction studies we concluded that the hormones may have stimulated the cells to reenter the cell cycle from G₀ because these values were increased by the hormones used. Estrogen can alter the S phase duration with a consequent increase in the rate of DNA synthesis which may explain the high DNA-labeling index observed in the present studies. Supported by Public Health Service grant CA38921 from the National Cancer Institute, Bethesda, MD, and by an Institutional grant from the United Foundation of Greater Detroit.     

Metrics from nonlinear dynamics adapted for characterizing the behavior of nonequilibrium enzymatic rate functions

Several metrics from nonlinear dynamics and statistical mechanics have been characterized on computer-generated number series with various signal-to-noise ratios, demonstrating their individual reliability as a function of sample size and their relationships to each other. The root mean square (RMS) evaluates amplitude, and the power spectral density (PSD) provides a visual display of the frequency spectrum; both measures have very high reliability even for an N as low as 50. The Fractal Dimension (D) is shown to converge rapidly and also to be reliable when N is as low as 50. These three measures (RMS, PSD, and D) have been applied to the complex kinetics of tyrosine hydroxylase time courses (50-point curves) at various BH4 concentrations (near physiological, but far from equilibrium levels). Recently developed measures of spectral entropy and the Liapunov Exponent, -lambda are also characterized.     

Degradation of [α-14C]hordenine in Hordeum vulgare plants

Evidence is presented indicating that intact plants of Hordeum vulgare degrade [α- ¹⁴C]hordenine to ¹⁴CO ₂.     

Reciprocal translocations in ageing mice and in mice with long-term low-level 239Pu contamination

Single intravenous injections of 185 Bq monomeric 239Pu were given to male mice, and the frequency of primary spermatocytes with reciprocal translocations, determined 724 days after treatment, was not significantly different from that of age-matched untreated controls. These old animals showed significantly higher aberration frequencies than young adults. The data therefore show that for low initial activity and very long retention time the possible cytogenetic effects of incorporated nuclide does not change the age-related pattern of increase of spontaneous chromosome aberrations. Considerations of the main variables involved in the induction of cytogenetic effects of incorporated plutonium, based on literature data, indicate that the initial injected activity, the estimated total accumulated average organ dose, and the retention time interact in a complex way; as far as can be seen at present, the effects seem to be dependent mainly on the initial activity at short times after contamination, while the retention time appears to be predominant in the case of long-term observations.     

Recurrent circuitry dynamically shapes the activation of piriform cortex

In the piriform cortex, individual odorants activate a unique ensemble of neurons that are distributed without discernable spatial order. Piriform neurons receive convergent excitatory inputs from random collections of olfactory bulb glomeruli. Pyramidal cells also make extensive recurrent connections with other excitatory and inhibitory neurons. We introduced channelrhodopsin into the piriform cortex to characterize these intrinsic circuits and to examine their contribution to activity driven by afferent bulbar inputs. We demonstrated that individual pyramidal cells are sparsely interconnected by thousands of excitatory synaptic connections that extend, largely undiminished, across the piriform cortex, forming a large excitatory network that can dominate the bulbar input. Pyramidal cells also activate inhibitory interneurons that mediate strong, local feedback inhibition that scales with excitation. This recurrent network can enhance or suppress bulbar input, depending on whether the input arrives before or after the cortex is activated. This circuitry may shape the ensembles of piriform cells that encode odorant identity.     

A partial proteome reference map of the wine lactic acid bacterium Oenococcus oeni ATCC BAA-1163

Oenococcus oeni is the main lactic acid bacterium that carries out the malolactic fermentation in virtually all red wines and in some white and sparkling wines. Oenococcus oeni possesses an array of metabolic activities that can modify the taste and aromatic properties of wine. There is, therefore, industrial interest in the proteins involved in these metabolic pathways and related transport systems of this bacterium. In this work, we report the characterization of the O. oeni ATCC BAA-1163 proteome. Total and membrane protein preparations from O. oeni were standardized and analysed by two-dimensional gel electrophoresis. Using tandem mass spectrometry, we identified 224 different spots corresponding to 152 unique proteins, which have been classified by their putative function and subjected to bioinformatics analysis.     

Cellular processes underlying cerebral cavernous malformations: Autophagy as another point of view

A growing amount of evidence indicates that autophagy plays a pivotal role in a plethora of human pathological conditions. We have recently broadened the list of the so-called autophagy-related diseases, describing the involvement of defective autophagy in the pathogenesis of cerebral cavernous malformations.