Maihle, Nita J.

AbstractBackgroundThe cardiac and respiratory cycles have been suggested as major drivers of cerebrospinal fluid(CSF) flow. The glymphatic system, one of the mechanisms for the clearance of amyloid‐beta and tau proteins, relies heavily on the movement(flow) of the CSF, and thus, investigating the forces that modulate the CSF flow is essential for understanding the glymphatic flux. Because breathing is trainable through exercise and self‐directed methods, various breathing methods may enhance the CSF flow.MethodReal‐time phase‐contrast MRI(pc‐MRI) was used to measure the CSF flow at the foramen magnum on a 3T. Fast resting‐state fMRI(rsfMRI;TR400ms) was conducted on a compact 3T. Under an IRB‐approved protocol, participants were instructed to breathe slowly and deeply, and subsequently switch to their spontaneous breathing. For rsfMRI data preprocessing, we performed motion correction, skull stripping, spatial smoothing(4mm), temporal filtering(0.01 to 0.1Hz), and linear and quadratic temporal trends removal. fMRI time courses were then normalized to Z‐score at each voxel before being averaged. On the pcMRI, the phase was summed in a CSF region‐of‐interest and plotted vs time. Additionally, we confirmed for possible confounding effects such as head motion or motion‐induced susceptibility changes.ResultrsfMRI findings showed that deep breathing promoted large oscillations in the CSF flow in the ventricles, while spontaneous breathing did not(Figure 1). Additionally, deep breathing resulted in large oscillations in lobar cortical regions. Similar results were observed in the pcMRI, with larger CSF velocity through the foramen magnum during the deep breathing compared to the spontaneous breathing(Figure 2A‐B). The cumulative summation result showed that the volume of CSF flow was increased during deep breathing(Figure 2C).ConclusionThis study provides new evidence that slow and deep breathing promotes CSF flow and global brain BOLD signal, which may be useful in promoting circulation in the brain. The study’s findings also open new avenues for research in the field of neurovascular coupling and mechanisms associated with glymphatic clearance. As hampered CSF flow and/or worsen glymphatic clearance have been shown to associate with pathological aging and dementia, including Alzheimer’s disease and Parkinson’s disease, future research is needed explore the potential of breathing training methods as a non‐pharmacological intervention to support brain health.

ABSTRACT Mutations in the ligand-binding domain of the epidermal growth factor receptor have been identified in several types of human cancers, including malignant gliomas. These mutations render signaling by this receptor to be constitutively ligand-independent. In fibroblasts transformed with ligand-independent epidermal growth factor receptor mutants, there is a correlation between the formation of a unique phosphotyrosine protein complex and oncogenic transformation. This phosphoprotein complex includes Grb2, Shc, Sos, tyrosine-phosphorylated form of caldesmon, and two, as yet, unidentified proteins. The presence of Grb2, Shc, and Sos in this complex implicates Ras in ligand-independent signaling by these oncogenic epidermal growth factor receptor mutants. We, therefore, have used retroviral co-infections of cultured primary fibroblasts to determine if Ras activation is required for phosphoprotein complex formation, stress fiber loss, or transformation. As predicted, expression of a dominant-negative Ras mutant (N17Ras) completely abrogates ligand-stimulated soft agar colony growth of primary fibroblasts. In contrast, N17Ras expression has no effect on v-ErbB mediated stress fiber disassembly, soft agar colony growth, or phosphoprotein complex assembly. In addition, our data suggest that ligand-dependent Ras activation may be suppressed by oncogenic v-ErbB expression. Together these observations suggest that oncogenic signaling by v-ErbB does not require Ras activation, and implicate an alternative signal transduction pathway in ligand-independent epidermal growth factor receptor oncogenic signaling.

Mutant v-erbB products of avian c-erbB1 have previously been used to correlate structural domains of the receptor encoded by this proto-oncogene with tissue-specific transformation potential. In these studies, deletion of the ligand-binding domain of the receptor has been shown to be required for transformation of erythroblasts, fibroblasts, and endothelial cells. It has, therefore, been postulated that deletion of this domain results in an allosteric change in the receptor analogous to the ligand-bound state of the epidermal growth factor receptor; i.e., it induces a receptor conformation that is constitutively active with respect to mitogenic signaling. While oncogenic v-erbB products have been shown to be expressed on the cell surface of both fibroblasts and erythroblasts, no comprehensive analysis of the oligomeric potential of these products has been conducted. Since the first event known to follow epidermal growth factor binding to its receptor is oligomerization, and receptor dimerization has been correlated with mitogenic signaling, we have carefully analyzed the ability of several v-erbB products to oligomerize in the three target cell types transformed by these oncogenes. In this report, we demonstrate the v-erbB products can efficiently homodimerize in all three target tissues, that this dimerization is ligand independent and occurs at the cell surface, and that there is no apparent correlation between v-erbB dimerization and transformation of avian fibroblasts. Furthermore, both oncogenic and nononcogenic v-erbB products can heterodimerize with the native c-erbB1 product in chicken embryo fibroblasts, suggesting that heterodimerization between v-erB and native c-erbB1 is not sufficient to result in c-erbB1-mediated sarcomagenesis.

Expression of mutant avian c-erbB1 genes results in tissue-specific transformation in chickens. Site-directed mutagenesis was used to generate kinase-defective mutants of several tissue-specific v-erbB transforming mutants by replacement of the ATP-binding lysine residue in the kinase domain with an arginine residue. These kinase-defective v-erbB mutants were analyzed for their in vitro and in vivo transforming potentials. Specifically, kinase-defective mutants of erythroleukemogenic, hemangioma-inducing, and sarcomagenic v-erbB genes were assessed for their oncogenic potential. In vitro transformation potential was assessed by soft-agar colony formation in primary cultures of chick embryo fibroblasts (CEF). In vivo transformation potential was determined by infection of 1-day-old line 0 chicks with concentrated recombinant retrovirus and then monitoring of birds for tumor formation. These transformation assays demonstrate that kinase activity is absolutely essential for transformation by tissue-specific transforming mutants of the avian c-erbB1 gene. Since all of the tissue-specific v-erbB mutants characterized to date exhibit tyrosine kinase activity in vitro but do not transform all tissues in which they are expressed, we conclude that v-erbB-associated tyrosine kinase activity may be necessary but is not sufficient to induce tumor formation.

Abstract The code for the human genome is essentially complete, opening an expansive book about our biologic composition. But the problem is to read this book. The font size is very small, What you are reading now is 9 point font, and genetic information would correspond to approximately 10-50 point font, six orders of magnitude smaller. There are methods to derive genetic information, but recently Adam Woolley, Chantal Guillemette, Chin-Li Cheung, David Housman, and Charles Lieber have developed an elegant way to directly read genetic information with a microscope. The microscope they used was an atomic force microscope (AFM) that employed a single-walled carbon nanotube as its probe.

Abstract Previous studies have implicated estrogen as a regulator of epidermal growth factor receptor (EGFR) expression in breast tumors. We therefore speculated that estrogen might modulate serologic soluble EGFR (sEGFR) concentrations in breast cancer patients. Accordingly, we measured serum sEGFR concentrations in postmenopausal women with metastatic breast cancer (MBC) treated with letrozole, an aromatase inhibitor that blocks estrogen synthesis. Serum specimens were obtained prior to and following 1 and 3 months of letrozole therapy. We report that sEGFR concentrations do not differ between MBC patients prior to letrozole treatment and age- and postmenopause-matched healthy women (P = 0.468). In contrast, however, sEGFR concentrations decreased significantly in 76% of MBC patients after both 1 month (P = 0.006) and 3 months (P = 0.003) of letrozole therapy versus pretreatment concentrations. Within the limitations of this study, we found no evidence for an association between pretreatment sEGFR concentrations or decreased treatment sEGFR concentrations and either progression-free or overall survival. Nonetheless, we conclude that future prospective studies are warranted to determine if baseline and/or longitudinal serum sEGFR concentrations may be useful for predicting disease progression and survival, and/or for monitoring responsiveness to aromatase inhibitors or other endocrine therapies in breast cancer patients.

Lung cancer is the leading cause of cancer-related death in the United States. Here, we evaluated the potential clinical utility of soluble human epidermal growth factor receptor 2 (sHER2) for the risk assessment, screening, and diagnosis of non-small cell lung cancer (NSCLC) using an unmatched case-control study design. Serum sHER2 concentrations were measured by immunoassay in 244 primary NSCLC cases and 218 healthy controls. Wilcoxon rank-sum tests, logistic regression models, and receiver operating characteristic plots were used to assess whether sHER2 is associated with lung cancer. Median serum sHER2 concentrations are higher in patients with adenocarcinoma than squamous cell carcinoma regardless of gender, and sHER2 is a weak, independent biomarker of adenocarcinoma, but not of squamous cell carcinoma, adjusted for age and gender. The age-adjusted relative risk (odds) of adenocarcinoma is 3.95 (95% CI: 1.22, 12.81) and 7.93 (95% CI: 2.26, 27.82) greater for women and men with high sHER2 concentrations (≥6.60 ng/mL) vs. low sHER2 concentrations (≤1.85 ng/mL), respectively. When adjusted for each other, sHER2, age, and gender discern healthy controls from patients with primary adenocarcinomas of the lung with 85.9% accuracy. We conclude that even though serum sHER2 is not a strong, stand-alone discriminatory biomarker of adenocarcinoma, sHER2 may be a useful, independent covariate in multivariate risk assessment, screening, and diagnostic models of lung cancer.