Distinct gene expression profiles of proximal and distal colorectal cancer: implications for cytotoxic and targeted therapy.

Colorectal cancer (CRC) is a heterogeneous disease with genetic profiles and clinical outcomes dependent on the anatomic location of the primary tumor. How location has an impact on the molecular makeup of a tumor and how prognostic and predictive biomarkers differ between proximal versus distal colon cancers is not well established. We investigated the associations between tumor location, KRAS and BRAF mutation status, and the messenger RNA (mRNA) expression of proteins involved in major signaling pathways, including tumor growth (epidermal growth factor receptor (EGFR)), angiogenesis (vascular endothelial growth factor receptor 2 (VEGFR2)), DNA repair (excision repair cross complement group 1 (ERCC1)) and fluoropyrimidine metabolism (thymidylate synthase (TS)). Formalin-fixed paraffin-embedded tumor specimens from 431 advanced CRC patients were analyzed. The presence of seven different KRAS base substitutions and the BRAF V600E mutation was determined. ERCC1, TS, EGFR and VEGFR2 mRNA expression levels were detected by reverse transcriptase-PCR. BRAF mutations were significantly more common in the proximal colon (P<0.001), whereas KRAS mutations occurred at similar frequencies throughout the colorectum. Rectal cancers had significantly higher ERCC1 and VEGFR2 mRNA levels compared with distal and proximal colon tumors (P=0.001), and increased TS levels compared with distal colon cancers (P=0.02). Mutant KRAS status was associated with lower ERCC1, TS, EGFR and VEGFR2 gene expression in multivariate analysis. In a subgroup analysis, this association remained significant for all genes in the proximal colon and for VEGFR2 expression in rectal cancers. The mRNA expression patterns of predictive and prognostic biomarkers, as well as associations with KRAS and BRAF mutation status depend on primary tumor location. Prospective studies are warranted to confirm these findings and determine the underlying mechanisms.

Patient satisfaction and impact of salivary flow rate on effectiveness of xerostomia products.

OBJECTIVES: To determine the types of products used to treat dry mouth and their perceived effectiveness, the relationship between salivary function and xerostomia symptoms, and whether salivary function predicts response to management strategies. STUDY DESIGN: Cross-sectional study of 87 patients with dry mouth and documented unstimulated whole salivary (UWS) and stimulated whole salivary (SWS) flow rates. Participants completed a questionnaire assessing dry mouth complaints and symptoms and effectiveness of specific dry mouth products. RESULTS: Mean (SD) age was 61.7 (12.9) years including 78 (90%) females. 47 (54%) participants had Sjögren's disease. Oral dryness symptoms (0-10 scale) rated highest with a mean (SD) of 7.2 (2.17); other symptoms scored from 3.4 to 5.1. Lower levels of UWS and SWS were associated with worse dry mouth and difficulty speaking, while lower levels of SWS flow alone were associated with greater difficulty swallowing and a decline in taste. More than half of the participants (55%, n = 48) reported using ≥4 dry mouth products. Participants with normal SWS flow had significantly better responses to lozenges and prescription products. CONCLUSIONS: Patients with dry mouth and normal stimulated flow rates (i.e., residual salivary capacity) respond better to stimulatory products (parasympathomimetic and lozenges). Salivary flow rate assessments may help with recommendations of dry mouth products.

Ground reaction force analysis of unilateral coxofemoral denervation for the treatment of canine hip dysplasia.

Coxofemoral denervation has success rates of 90-96% reported retrospectively for palliative treatment of hip dysplasia. The aim of this study was to objectively evaluate ground reaction forces (GRF) in dysplastic dogs after unilateral denervation. Unilateral coxofemoral denervation was performed by means of a previously reported technique on 10 dogs with asymmetric gait. GRF were measured at zero, one and three months. Statistical analysis was performed using repeated measures analysis of variance and paired t-tests, with p< or =0.05. There was a lack of significant difference in mean peak vertical force (PVF) or vertical impulse (VI) in the operated limb (TX) over time. For the unoperated limb (UnTX), mean PVF and VI significantly decreased over time. The dogs were significantly more lame in the TX limb initially and at one month, however, there was no significant difference between limbs by three months. In the UnTX limb, 40% of dogs decreased PVF by >5%, by three months. Over time, there was no significant difference in mean average rise or mean average fall for TX or UnTX limbs. Between limbs, mean rise in the TX limb was significantly less at zero months, but not at one or three months. Decreased compensatory load shifting to the UnTX limb due to procedural efficacy could explain decreases in the UnTX limb. Worsening disease could also explain decreases in the UnTX limb, and may indicate a protective effect denoted by a lack of change in the TX limb. Longer follow-up would be required in improved dogs in order to document continued efficacy.

In vitro perfusion of hybrid artificial pancreas devices at low flow rates.

Type I diabetes is characterized by insulin insufficiency due to lack of functional beta cells. To replace injection therapy, schemes such as the Hybrid Artificial Pancreas (HAP) were developed. This consists of an acrylic housing enclosing a semipermeable hollow fiber membrane. Donor islets can be seeded in the annular space through a port in the housing, and thus are separated from the recipient's bloodstream or perfusate. Before scaling the HAP to human size, the dynamics of its insulin response to a perfusion glucose challenge must be better understood. In this study, the HAP's insulin response after a step increase in the lumenal glucose concentration was determined as a function of the radial thickness of the annular space (0.173-0.973 mm) and islet distribution at a flow rate of 1 ml/min. Devices containing a single, 65 mm long fiber were used. Rat islets were isolated using standard collagenase digestion techniques. In unseeded HAP perfusions, the washout time for glucose and insulin from the annular space was dependent on flow rate and radial thickness. Both solutes were removed in < 3 min from the smallest devices when perfused at 10 ml/min. Thus, solute transport within the HAP is very fast. In the seeded HAP perfusions, the devices were subjected to a step increase in the lumenal glucose concentration. Sequential samples of the HAP effluent were collected and assayed for glucose and insulin. The spatial distribution of the islets in the annular space was one of the most important factors in determining the HAP's insulin response.(ABSTRACT TRUNCATED AT 250 WORDS)

From oral traditions to elementary textbooks: a description of the maternal languages project in Niger.

PIP: Niger is experimenting with maternal language instruction in grades 1-3, within a broader context of educational reform. In these early grades, some 25 experimental schools distributed throughout the country are using 1 of 5 national languages -- Hausa, Zarma-Songhai, Fulfulde, Tamajaq, or Kanuri -- as the language of instruction and of standardized examinations, as in traditional schools. The curriculum in these experimental schools for the early grades is also innovative and favors an interdisciplinary approach. Lessons in various subjects are linked at any given time by a them selected by teachers and students. Niger's national pedagogical institute, in collaboration with the US Agency for International Development (USAID), designed a testbook project which was built around a recorded collection of oral traditions. Once assembled, this collection served as a resource to draw on for production of readers for grades 1 through 3. These readers provide content appropriate to the curriculum and serve as an archive of oral traditions for future use. The Institute's procedure for producing elementary readers in maternal languages has not only yielded the desired books but has also facilitated institutional development in several organizations committed to producing national language materials. The project has had several phases, including the collection, transcription, and cataloging of oral materials; the preselection, adaptation, final editing, and illustration of tests; the publication of the textbooks; and the evaluation of the textbooks. Over 70 primary school teachers participated in the collection phase during the summer vacation of 1981. The teachers were selected to assure a distribution of regions and dialects for each of the 5 languages. Before returning to their villages, trainees were issued Panasonic RQ 230 9A tape recorders, batteries, and a box of 20 cassettes. Supervisory teams composed of at least 1 linguist and 1 pedagogical advisor visited each collector twice during the following 2 months. Near the end of the school year, preparations beganfor a 2-weed working seminar in August. Seminar participants would review and revise preedited texts for final publication. The texts were modified in several ways. They were further adapted from an oral to a written medium by eliminating excessive repetitions, or by filling in plot elements a performer had eliminated. Establishing proofreading groups was a final innovation. Book production prompted another training effort in July 1983. Overall, the project design has functioned very well. In the process of producing the 1st series of textbooks, the values and aesthetics of several cultures' oral art forms have been transformed into written form for classroom use, teachers, and others have increased their national language skills, and a system that profits from the cooperative efforts of sister institutions has been developed.^ieng

The 'consumer-as-provider' initiative.

The National Institute of Mental Health has provided funding in Region I (New England) to several technical assistance centers: the Center for Community Change through Housing and Supports (Vt.); the Human Resource Association of the Northeast (Mass.); and the recently funded National Empowerment Center (Mass.). These federally funded projects are focused on guiding the mental health field toward a more consumer-driven system. The authors have been involved with these organizations and also provide consultation along with Northern Rhode Island Community Mental Health Center (NRICMHC) staff and consumers to other counties and states on improving services for adults and children with longer-term psychiatric problems. The consulting team for NRICMHC has encountered some communities where the hiring of current or former consumers appeared to present a "quick fix" for system problems rather than a reflection of more fundamental changes in attitudes and programs. Based on the authors' personal and family experiences, as well as their work experiences, they have reexamined some of the conventional wisdoms in the rapidly evolving area of "consumers as providers."

Electrical measurements of complement-mediated membrane damage in cultured nerve and muscle cells.

Cultured neuroblastoma-glioma hybrid cells and primary mouse and rat muscle cells were studied by using intracellular microelectrodes to monitor membrane electrical potential and resistance changes during complement-mediated lysis. The cell membrane was TNP modified under mild conditions and subsequently coated with rabbit IgG anti-TNP, with no electrical changes observed. However, upon addition of guinea pig C the membrane potential dropped from approximately -50 mv to less than -12 mv within a few minutes, with parallel decreases in electrical resistance. Ten to 60 min after these electrical changes the cells became stainable with trypan blue. No electrical changes or trypan blue staining was observed in the absence of antibody or with heat-inactivated C. With more dilute C so that only a fraction of cells became trypan blue positive, all cells nevertheless showed the membrane electrical changes; surviving cells recovered their original membrane properties within 1 hr. Thus the C-mediated damage to the membrane measured electrically is not in itself sufficient to ensure the subsequent death of the cell. The early electrical changes observed appear to be comparable to increases in 86Rb efflux measured by others.

Cyclic variation of potassium conductance in a burst-generating neurone in Aplysia.

1. The hyperpolarization between bursts in the R 15 cell of Aplysia is accompanied by an increase in membrane slope conductance.2. The post-burst hyperpolarization can be observed with ouabain, lithium, or potassium-free solution if artificial inward current is applied. The hyperpolarization can be observed with dinitrophenol or cooling to 10 degrees C, with no injected current. Thus, the hyperpolarization apparently is not due to the cyclic activity of an electrogenic pump.3. A reversal potential for the post-burst hyperpolarization can be demonstrated by passage of inward current during the inter-burst period. The reversal of direction of the potential depends on recent occurrence of a burst.4. The reversal potential varies with external potassium concentration, but not with chloride or sodium.5. The post-burst hyperpolarization is not blocked by external tetraethylammonium at a concentration which greatly prolongs the action potentials.6. During the onset of spike blockage by, and recovery from, calcium-free+tetrodotoxin saline, the bursts of action potentials appear to be driven by endogenous waves of membrane potential.7. The hyperpolarizing phase of the waves in calcium-free+tetrodotoxin medium is accompanied by an increased slope conductance.8. A reversal potential can be demonstrated for the hyperpolarization following a wave in calcium-free+tetrodotoxin medium by applying inward current during the interwave period.9. The waves in calcium-free+tetrodotoxin medium are blocked by ouabain but can be reinstated by artificial hyperpolarization.10. The post-burst hyperpolarization and the post-wave hyperpolarization appear to result from a periodic increase in membrane conductance, primarily to potassium ions.

Single channel currents induced by complement in antibody-coated cell membranes.

An extracellular patch electrode was used to record ionic currents from individual complement-induced channels in the membranes of antibody-coated skeletal muscle. The amplitude of the single-channel currents leads to an estimate of 90 pS for the unit conductance. The kinetics of channel opening and closing show marked variability and complexity. Channels flicker open and closed repeatedly, indicating that once these lesions form, they undergo rapid structural transitions between discrete conducting and nonconducting states.

Computerized tomographic imaging of cryosurgical iceball formation in brain.

Computerized tomography (CT) was used to monitor the exact anatomical location and dimensions of the cryosurgical iceball within the brain. The gross and microscopic appearance of the tissue iceball was examined in both acute and chronic animals. Iceball formation was monitored in the brain of four dogs under a general anesthesia. The radiographic image of the iceball was that of a well-demarcated radiolucent sphere that disappeared upon thawing. The post-thaw contrast-enhanced CT scan revealed a zone of blood-brain barrier breakdown extending no more than 1 mm beyond the maximum diameter that the iceball had attained. Histological examination demonstrated a sharp transition from frankly necrotic brain within the iceball to the normal cytoarchitecture of the surrounding neuropil. The safety and efficacy of a neurosurgical ablative procedure depends on the precision with which it can be generated. The use of CT imaging to monitor the formation of the cryosurgical iceball offers the neurosurgeon a means to precisely control the size of the ablative lesion. Small deeply situated brain tumors can be incorporated into the iceball under direct CT observation, thereby ensuring the completeness of the cryoablation while minimizing damage to the surrounding brain.

Solute washout experiments for characterizing mass transport in hollow fiber immunoisolation membranes.

The transport characteristics of immunoisolation membranes can have a critical effect on the design of hybrid artificial organs and cell therapies. However, it has been difficult to quantitatively evaluate the desired transport properties of different hollow fiber membranes due to bulk mass transfer limitations in the fiber lumen and annular space. An attractive alternative to existing methodologies is to use the rate of solute removal or "washout" from the annular space during constant flow perfusion through the fiber lumen. Experimental washout curves were obtained for glucose and a 10 kD dextran in two different hollow fiber devices. Data were analyzed using a theoretical model which accounts for convective and diffusive transport in the lumen, membrane, and annular space. The model was in good agreement with the experimental results and provided an accurate measure of the effective membrane diffusion coefficient for both small and large solutes. This approach should prove useful in theoretical analyses of solute transport and performance of hollow fiber artificial organs.