Factors contributing to seasonal increases in inoculative freezing resistance in overwintering fire-colored beetle larvae dendroides canadensis

The insects and microarthropods that vary seasonally in susceptibility to cross-cuticular inoculation by external ice (inoculative freezing) represent a phylogenetically diverse group; however, few studies have explored possible mechanisms experimentally. This study documents seasonally variable inoculative freezing resistance in Dendroides canadensis beetle larvae and combines immunofluorescence, in vivo removal of epicuticular lipids and in vitro chamber studies to explore the roles of seasonal modification in the cuticle and in epidermal and hemolymph antifreeze proteins (AFPs). Seasonal cuticular modifications contribute to the inhibition of inoculative freezing since more cold-hardy larvae froze inoculatively when epicuticular waxes were removed with hexane and, in in vitro chamber experiments, cuticle patches (with the underlying epidermis removed) from winter larvae provided greater protection from inoculative freezing than did cuticle patches from summer larvae. The results indicate that seasonal modifications in epidermal and hemolymph AFPs contribute most strongly to the inhibition of inoculative freezing. Subcuticular epidermal AFPs were present in immunocytochemically labeled transverse sections of winter larvae but were absent in summer ones. Winter integument patches (cuticle with epidermis) were more resistant to inoculative freezing than were summer integument patches. Integument patches resisted inoculative freezing as well as live winter-collected larvae only when hemolymph AFP was added. The results also suggest that some integumentary ice nucleators are removed in cold-hardy larvae and that AFP promotes supercooling by inhibiting the activity of these nucleators.

The lack of correlation between inhibition of aggregation and cAMP levels with canine platelets.

Arachidonic acid (AA) induced aggregation of canine platelets can be inhibited by various phosphodiesterase inhibitors (PDIs) with the order of potency IBMX greater than or equal to papaverine greater than Ro 20-1724 greater than theophylline. With aggregation induced by AA plus epinephrine (EPI), only IBMX and papaverine inhibited at 100 microM. None of these PDIs affected the basal cAMP levels but all potentiated the PGE1-stimulated cAMP production, with the order of potency being Ro 20-1724 greater than papaverine greater than IBMX greater than theophylline. PGE1 at 1 microM caused a sharp increase in cAMP and complete inhibition of platelet aggregation induced by AA plus EPI. However, when EPI was added before PGE1, there was no elevation of cAMP yet inhibition of aggregation still occurred. Our results indicated that inhibition of platelet aggregation does not require a measurable increase in cAMP.

Breast-feeding policies and routines among Arizona hospitals and nursery staff: results and implications of a descriptive study.

In 1988, Arizona's 61 hospitals providing obstetrical services were canvased with regard to hospital routines that favor either breast-feeding or bottle-feeding. Forty-five hospitals provided responses that were used in the survey. Practices favoring breast-feeding, which were reported by a majority of the hospitals (more than 50%), were demand feeding, staff assessment for "latch-on" (the action of nipple presentation and sucking initiation) and positioning, "rooming-in" (the practice of minimal mother-infant separation), and information about follow-up support services. Hospital practices suggested to promote bottle-feeding were the provision of pacifiers and supplemental water or glucose, issuance of formula packs at discharge, and a first feed of sterile water. A positive significant relationship was identified for policies advocating breast-feeding and the prevalence of breast-feeding encouragement from professional staff. Of 44 respondents, 41 indicated that their hospital's policies endorse breast-feeding as the ideal method of feeding healthy newborns. Hospital staff perceived that they encourage mothers to breast-feed and offer support to those who initiate breast-feeding. On the basis of this information, we conclude that dietetics practitioners should evaluate current breast-feeding practices and integrate policies supportive of breast-feeding into the health care system.

A molecular characterization of the choroid plexus and stress-induced gene regulation.

The role of the choroid plexus (CP) in brain homeostasis is being increasingly recognized and recent studies suggest that the CP has a more important role in physiological and pathological brain functions than currently appreciated. To obtain additional insight on the CP function, we performed a proteomics and transcriptomics characterization employing a combination of high resolution tandem mass spectrometry and gene expression analyses in normal rodent brain. Using multiple protein fractionation approaches, we identified 1400 CP proteins in adult CP. Microarray-based comparison of CP gene expression with the kidney, cortex and hippocampus showed significant overlap between the CP and the kidney. CP gene profiles were validated by in situ hybridization analysis of several target genes including klotho, CLIC 6, OATP 14 and Ezrin. Immunohistochemical analyses were performed for CP and enpendyma detection of several target proteins including cytokeratin, Rab7, klotho, tissue inhibitor of metalloprotease 1 (TIMP1), MMP9 and glial fibrillary acidic protein (GFAP). The molecular functions associated with various proteins of the CP proteome indicate that it is a blood-cerebrospinal fluid (CSF) barrier that exhibits high levels of metabolic activity. We also analyzed the gene expression changes induced by stress, an exacerbating factor for many illnesses, particularly mood disorders. Chronic stress altered the expression of several genes, downregulating 5HT2C, glucocorticoid receptor and the cilia genes IFT88 and smoothened while upregulating 5HT2A, BDNF, TNFα and IL-1b. The data presented here attach additional significance to the emerging importance of CP function in brain health and CNS disease states.

[Clinical and prognostic aspects of multiple cancers]. / Klinische und prognostische Aspekte von Mehrfachkarzinomen.

The anamnestic data, course and prognosis for 76 patients with multiple carcinomas were statistically analyzed in a retrospective study undertaken jointly with the oncological working group. The importance of multidisciplinary care for this group of patients over a period exceeding five years must be emphasized. If the general status of a patient deteriorates, the doctor should always consider the possibility of a second or third carcinoma.

Influence of collateral blood flow and of variations in MVO2 on tissue-ATP content in ischemic and infarcted myocardium.

The left anterior descending coronary artery was occluded for 22.5, 45, 90, 180, and 360 mins in anesthesized open-chest dogs and pigs and thereafter reperfused for 30 min. Myocardial oxygen consumption was varied in dogs by cholinergic stimulation (bradycardia) and by cutting of the right and left vagus nerve (tachycardia). Regional myocardial blood flow was measured with radioactive tracer microspheres at the end of the occlusion period and 5 and 30 min after reflow. Tissue content of adenine nucleotides and of phosphocreatine were determined in the subendo- and subepicardium of transmural biopsies at the end of reflow. Infarct size was determined with nitrobluetetrazolium and compared with risk region size. Porcine hearts developed infarcts sooner. Those canines with a high MVO2 due to tachycardia had larger infarcts than those with bradycardia and resembled infarct development in the pig. The evolution of infarcts with time depended strongly on collateral flow which was significantly higher in canine hearts. Higher collateral flow and lower MVO2 in one group of canine hearts also resulted in better preserved tissue ATP. The fall in tissue ATP with time after coronary occlusion was compared with the O2-supply via collateral flow during occlusion. Assuming that the oxygen entering ischemic myocardium was used for ADP phosphorylation, we could estimate the degree of ATP-"overspending". Overspending was highest in low-flow ischemia and it correlated well with the speed of infarction. The ATP-data are best explained by the phosphocreatine energy shuttle model and by assuming slow access of cytosolic ATP to the ATP-splitting sites at the myofibrils. In conclusion, we postulate that both collateral flow as well as myocardial oxygen consumption before and during occlusion determine infarct size.

The regulation of nucleotide metabolism of immune cells: papaverine induced nucleotide breakdown.

During a period of prelabeling of mouse thymus cells with any nucleoside at 4 degrees C, nucleoside phosphates accumulated, but no nucleic acid synthesis occurred. Elevating the temperature to 37 degrees C then led to incorporation into the respective nucleic acid reaching a maximum in 5--15 min. Papaverine inhibited this incorporation (IC50:50 muM) and caused an efflux of label into the medium as a nonphosphorylated product. The responses of the different nucleotide phosphate pools showed more dependency on the base then the sugar moeity. The effect of papaverine could not be altered or mimicked by deprivation of oxygen, glucose, or calcium. Mouse spleen cells responded like thymocytes to papaverine, but rat GH3 pituitary cell DNA syntesis was only transiently inhibited with no concomitant efflux of 3H into the medium. As expected, thymus cellular adenosine triphosphate (ATP), determined by the luciferin-luciferase reaction, decreased in the presence of papaverine; suprisingly, extracellular ATP fell as well. The results suggest that decreases in cellular ATP of mouse thymus cells leads to reductions of all nucleoside phosphates and the efflux of the resultant nucleosides. Papaverine may effect a decrease in the ATP levels by activating a phosphohydrolase rather than, or in addition to, the previously suggested inhibition of mitochondrial electron transport.

Effect of myocardial oxygen consumption on infarct size in experimental coronary artery occlusion.

The influence of myocardial oxygen consumption (MVO2) at the moment of coronary occlusion on the size of the ensuing necrosis was investigated in 12 anaesthetised dogs. A two-infarction model was used with a sequential occlusion of two distant coronary branches in the same heart, however under different levels of MVO2. One group of occlusions was produced at a high MVO2 of 21.6 +/- 3.0 ml O2 . min-1 . 100 g-1. This group was compared with a second in which necrosis proceeded at a low MVO2 estimated to be 5.9 +/- 1.5 ml O2 . min-1 . 100 g-1 averaged over a 90-min occlusion period. Infarct size expressed as percentage of perfusion area was 43 +/- 28% in group 1 and 11 +/- 11% in group 2 (p less than 0.005). The mass of the perfusion area was equal in both groups (17 +/- 4 g, 19 +/- 6 g). The amount of myocardial necrosis, which after a 90-min occlusion depends on the acute collateral blood flow, was in every case greater under high MVO2. Thus a low MVO2 at the moment of occlusion can postpone myocardial necrosis.