Art and craft material use patterns by pre-school and elementary school children at home and school: a year long survey for refining exposure assessments

BACKGROUND

Use frequency and times are critical parameters for estimating realistic chemical exposures associated with the use of consumer products. Very limited information is available in the published literature for children's use patterns of art and craft materials at home and school.

OBJECTIVE

Conduct a year-long survey of art materials use at home and school by pre-school and elementary school children, teachers, and parents which can be used to refine chemical exposure assessments for these consumer products.

METHODS

Parent and teacher online surveys were conducted on the daily use of markers and monthly use of fifteen additional art and craft materials.

RESULTS

Daily marker use by elementary children was widespread at home and school (65% and 80%, respectively). On average, pre-school and elementary students used markers for 27 min per day, more than double daily home use. Adults used markers for longer durations relative to their children/students with teachers reporting the highest average daily usage time. School use of general art materials exceeded home use for both age groups, with elementary children using art materials more frequently than their pre-school counterparts. Examples of how these data can be used to refine exposure estimates are provided.

SIGNIFICANCE

Accurate art material usage data contributes to refined estimates of chemical exposure for these consumer products.

IMPACT STATEMENT

A year-long online survey was conducted which measured daily frequency and duration use for markers and comparable monthly use of other art materials for pre-school and elementary school children, their parents and teachers. Such use information is critical for estimating chemical exposures associated with this class of consumer products.

Tumour, narrow pelvis and surgery specific factors for total mesorectal excision quality and morbidity following rectal cancer resection

BACKGROUND

Pelvic anatomy is critical in challenging rectal resections. This study investigated how pelvic anatomy relates to total mesorectal excision (TME) quality, anastomotic leakage rate, and long-term oncological outcomes.

METHODS

Patients undergoing elective rectal cancer resection from 2008 to 2017 in an Austrian institution were retrospectively reviewed regardless of the surgical approach. CT scans were analysed for pelvic measurements and volumes. The primary outcomes of interest were the correlation between pelvic dimensions and the TME quality and anastomotic leakage. Subanalysis was done by surgical approach (open, laparoscopic, transanal TME). Secondary outcomes were overall and disease-free survivals.

RESULTS

Among 154 eligible patients, 112 were included. The angle between pubic symphysis and promontory significantly correlated with worse TME grades (TME grade 1: mean(s.d.) 102.7(5.7)°; TME grade 2: 92.0(4.4)°; TME grade 3: 91.4(3.6)°; P < 0.001). A significantly lower distance between tumour and circumferential resection margin (CRM) was observed in grade 3 resections, whereas no difference appeared in grade 1 and grade 2 resection (TME grade 1: mean(s.d.) 11.92(9.4) mm; TME grade 2: 10.8(8.1) mm; TME grade 3: 3.1(4.1) mm; P = 0.003). The anastomotic leakage rate was significantly higher in case of a lower CRM (patients with anastomotic leakage: mean(s.d.) 6.8(5.8) mm versus others: 12.6(9.8) mm, P = 0.027), but not associated with pelvimetry measurements. The transanal TME (TaTME) subgroup displayed a wider angle between the pubic symphysis and promontory, younger age and improved TME quality compared to others (respectively, mean TME grades in TaTME versus open versus laparoscopic: 1.0 ± 0.0, 1.5 ± 0.7 and 1.3 ± 0.5, P = 0.013). Finally, oncological survival was not impacted by pelvic measurements or worse TME quality.

CONCLUSION

The angle between the pubic symphysis and promontory and the distance between tumour and CRM were associated with worse TME grades. The anastomotic leakage was associated with a lower CRM but not with pelvimetric measures.

Sarcopenic Obesity Is a Risk Factor for Worse Oncological Long-Term Outcome in Locally Advanced Rectal Cancer Patients: A Retrospective Single-Center Cohort Study

BACKGROUND

Malnutrition and skeletal muscle waste (sarcopenia) are known as predictive factors for a poor postoperative outcome. Paradoxically, obesity seems to be associated with a survival advantage in wasting diseases such as cancer. Thus, the interpretation of body composition indices and their impact on rectal cancer therapy has become more and more complex. The aim of this study was to evaluate body composition indices in locally advanced rectal cancer patients prior to therapy and their impact on short- and long-term outcomes.

METHODS

Between 2008 and 2018, 96 patients were included in this study. Pre-therapeutic CT scans were used to evaluate visceral and subcutaneous fat mass, as well as muscle mass. Body composition indices were compared to body mass index, morbidity, anastomotic leakage rate, local recurrency rate, and oncological long-term outcomes.

RESULTS

Increased visceral fat (p < 0.01), subcutaneous fat (p < 0.01), and total fat mass (p = 0.001) were associated with overweight. Skeletal muscle waste (sarcopenia) (p = 0.045), age (p = 0.004), comorbidities (p < 0.01), and sarcopenic obesity (p = 0.02) were significantly associated with increased overall morbidity. The anastomotic leakage rate was significantly influenced when comorbidities were present (p = 0.006). Patients with sarcopenic obesity showed significantly worse disease-free (p = 0.04) and overall survival (p = 0.0019). The local recurrency rate was not influenced by body composition indices.

CONCLUSION

Muscle waste, older age, and comorbidities were demonstrated as strong risk factors for increased overall morbidity. Sarcopenic obesity was associated with worse DFS and OS. This study underlines the role of nutrition and appropriate physical activity prior to therapy.

Are risk factors for anastomotic leakage influencing long-term oncological outcomes after low anterior resection of locally advanced rectal cancer with neoadjuvant therapy? A single-centre cohort study

PURPOSE

Anastomotic leakage (AL) poses the most serious problem following low anterior resection in patients with rectal cancer independent of surgical approach or technique. The aim of this study was to evaluate risk factors for the occurrence of AL and how they affect the oncological long-term outcome of patients who received neoadjuvant therapy.

METHODS

A single centre cohort study of 163 consecutive locally advanced rectal cancer patients (cT3, cT4, N +) that received neoadjuvant therapy followed by resection with primary anastomosis between January 1998 and December 2020 were included in this study. Short- and long-term findings were compared between patients with AL (Leakage +) and without AL (Leakage -).

RESULTS

A complete follow-up was obtained from 163 patients; thereby, 33 patients (20%) developed an AL. We observed more patients with comorbidities (38% vs. 61%, p = 0.049) which developed a leakage in the course. Permanent stoma rate (36% vs. 18%, p = 0.03) was higher, and time between primary operation and stoma reversal was longer (219 days [172-309] vs. 93 days [50-182], p < 0.001) in this leakage group as well. Tumour distance lower than 6 cm from the anal verge (OR: 2.81 [95%CI: 1.08-7.29], p = 0.04) and comorbidities (OR: 2.22 [95%CI: 1.01-4.90], p = 0.049) was evaluated to be independent risk factors for developing an AL after rectal cancer surgery. Oncological outcome was not influenced by AL nor by other associated risk factors.

CONCLUSION

We could clearly detect the distance of tumour from the anal verge and comorbidities independent risk factors for the occurrence of AL. Oncological findings and long-term outcome were not influenced by these particular risk factors.

Is Robotic Assisted Colorectal Cancer Surgery Equivalent Compared to Laparoscopic Procedures during the Introduction of a Robotic Program? A Propensity-Score Matched Analysis

Simple Summary

The introduction of a robotic program is challenging and requires extensive experience in minimally invasive surgery. Short-term outcomes and oncological quality should not differ between robotic and laparoscopic surgery. To our knowledge, no data on the quality of surgery at the time of introduction of the robotic platform are available. The aim of this study was to compare short-term outcomes and oncological findings of robotic-assisted colorectal resections with those of conventional laparoscopic surgery within the first three years after the introduction of the robotic platform.

Abstract

Background: Robotic surgery represents a novel approach for the treatment of colorectal cancers and has been established as an important and effective method over the last years. The aim of this work was to evaluate the effect of a robotic program on oncological findings compared to conventional laparoscopic surgery within the first three years after the introduction. Methods: All colorectal cancer patients from two centers that either received robotic-assisted or conventional laparoscopic surgery were included in a comparative study. A propensity-score-matched analysis was used to reduce confounding differences. Results: A laparoscopic resection (LR Group) was performed in 82 cases, and 93 patients were treated robotic-assisted surgery (RR Group). Patients’ characteristics did not differ between groups. In right-sided resections, an intracorporeal anastomosis was significantly more often performed in the RR Group (LR Group: 5 (26.31%) vs. RR Group: 10 (76.92%), p = 0.008). Operative time was shown to be significantly shorter in the LR Group (LR Group: 200 min (150–243) vs. 204 min (174–278), p = 0.045). Conversions to open surgery did occur more often in the LR Group (LR Group: 16 (19.51%) vs. RR Group: 5 (5.38%), p = 0.004). Postoperative morbidity, the number of harvested lymph nodes, quality of resection and postoperative tumor stage did not differ between groups. Conclusion: In this study, we could clearly demonstrate robotic-assisted colorectal cancer surgery as effective, feasible and safe regarding postoperative morbidity and oncological findings compared to conventional laparoscopy during the introduction of a robotic system.

The Influence of VE-Cadherin on Adhesion and Incorporation of Breast Cancer Cells into Vascular Endothelium

During metastasis, cancer cells that originate from the primary tumor circulate in the bloodstream, extravasate, and form micrometastases at distant locations. Several lines of evidence suggest that specific interactions between cancer cells and endothelial cells, in particular tumor cell adhesion to the endothelium and transendothelial migration, play a crucial role in extravasation. Here we have studied the role of vascular endothelial (VE)-cadherin which is expressed aberrantly by breast cancer cells and might promote such interactions. By comparing different human breast cancer cell lines, we observed that the number of cancer cells that adhered to endothelium correlated with VE-cadherin expression levels. VE-cadherin silencing experiments confirmed that VE-cadherin enhances cancer cell adhesion to endothelial cells. However, in contrast, the number of cancer cells that incorporated into the endothelium was not dependent on VE-cadherin. Thus, it appears that cancer cell adhesion and incorporation are distinct processes that are governed by different molecular mechanisms. When cancer cells incorporated into the endothelial monolayer, they formed VE-cadherin positive contacts with endothelial cells. On the other hand, we also observed tumor cells that had displaced endothelial cells, reflecting either different modes of incorporation, or a temporal sequence where cancer cells first form contact with endothelial cells and then displace them to facilitate transmigration. Taken together, these results show that VE-cadherin promotes the adhesion of breast cancer cells to the endothelium and is involved in the initial phase of incorporation, but not their transmigration. Thus, VE-cadherin might be of relevance for therapeutic strategies aiming at preventing the metastatic spread of breast cancer cells.

Positive effects of lumbar puncture simulation training for medical students in clinical practice

BACKGROUND

Lumbar puncture (LP) is an invasive medical procedure that can be done by any doctor. Several simulation-based trainings have been built however the evaluations of the theoretical knowledge and the impact of the simulation-based training have never been performed in real life. The objective was to evaluate the impact of a LP training on the theoretical knowledge improvement and the performance of a LP in clinical practice.

METHODS

Before and after medical students' training, theoretical knowledge and confidence level were assessed. Over a 6 months period, the impact of simulation training was evaluated by the success rate of students' first LP carried out in hospitalized patients and compared to the results of a no-training control.

RESULTS

Students' theoretical knowledge and confidence level showed significant improvement after simulation training on 115 students (p < 0.0001). The evaluation in real life based on 41 students showed that the success rate of the first LP in patients was higher in the LP simulation group compared to the control group (67% vs 14%, p = 0.0025). The technical assistance was also less frequently needed in the LP simulation group (19% vs 57%, respectively, p = 0.017). The rate of students who participated in this educational study was low.

DISCUSSION

Simulation-based teaching was an effective way to improve students' theoretical and practical knowledge. Whether this approach translates to other procedural skills in real clinical settings merits further study. The low participation rate in the study is due to the fact that students are not used to be included in educational studies and to the complexity of evaluation in routine clinical practice.

Enzymatic accessibility of fiber hemp is enhanced by enzymatic or chemical removal of pectin

Pectinolytic enzymes, steam explosion and alkaline treatment were used to assess the role of pectin for the accessibility of hydrolytic enzymes in the enzymatic hydrolysis of biomass. Hemp (Cannabis sativa L.), a potential energy crop especially in boreal climate with a low need of fertilizers, was used in the study either as untreated or anaerobically preserved raw material. Addition of pectinases increased the hydrolysis yield by 26%, 54%, and 64% from the theoretical carbohydrates of untreated, acid, and alkali-preserved materials, respectively. Steam explosion and hot alkali treatment increased the conversion of the total carbohydrates by 78% and 60%, respectively, compared to the untreated hemp. Elevated separation of cells within the hemp stalk tissues and an increased surface area was revealed after hot alkali or pectinase treatments, contributing to the increased conversion to sugars by commercial enzymes.

Evidence for a spin-aligned neutron-proton paired phase from the level structure of (92)Pd

Shell structure and magic numbers in atomic nuclei were generally explained by pioneering work that introduced a strong spin-orbit interaction to the nuclear shell model potential. However, knowledge of nuclear forces and the mechanisms governing the structure of nuclei, in particular far from stability, is still incomplete. In nuclei with equal neutron and proton numbers (N = Z), enhanced correlations arise between neutrons and protons (two distinct types of fermions) that occupy orbitals with the same quantum numbers. Such correlations have been predicted to favour an unusual type of nuclear superfluidity, termed isoscalar neutron-proton pairing, in addition to normal isovector pairing. Despite many experimental efforts, these predictions have not been confirmed. Here we report the experimental observation of excited states in the N = Z = 46 nucleus (92)Pd. Gamma rays emitted following the (58)Ni((36)Ar,2n)(92)Pd fusion-evaporation reaction were identified using a combination of state-of-the-art high-resolution γ-ray, charged-particle and neutron detector systems. Our results reveal evidence for a spin-aligned, isoscalar neutron-proton coupling scheme, different from the previous prediction. We suggest that this coupling scheme replaces normal superfluidity (characterized by seniority coupling) in the ground and low-lying excited states of the heaviest N = Z nuclei. Such strong, isoscalar neutron-proton correlations would have a considerable impact on the nuclear level structure and possibly influence the dynamics of rapid proton capture in stellar nucleosynthesis.

Young adults and higher education: barriers and breakthroughs to success

Although access to higher education has increased substantially over the past forty years, student success in college--as measured by persistence and degree attainment--has not improved at all. Thomas Brock reviews systematic research findings on the effectiveness of various interventions designed to help at-risk students remain in college. Brock shows how changes in federal policy and public attitudes since the mid-1960s have opened up higher education to women, minorities, and nontraditional students and also shifted the "center of gravity" in higher education away from traditional four-year colleges toward nonselective community colleges. Students at two-year colleges, however, are far less likely than those at four-year institutions to complete a degree. Brock argues that the nation's higher education system must do much more to promote student success. Three areas, he says, are particularly ripe for reform: remedial education, student support services, and financial aid. In each of these three areas, Brock reviews programs and interventions that community colleges have undertaken in order to raise completion rates. Some colleges have, for example, experimented with remedial programs that build social cohesion between students and faculty and integrate content across courses. Other colleges have tested student support service programs that offer counseling and advising that are regular, intensive, and personalized. Still others have experimented with ways to simplify the financial aid application process and incentivize students to earn good grades and persist in school. Research shows that such programs and interventions can improve student outcomes, but Brock argues that more must be done to bring proven practices to scale and to test new ideas that might lead to better results. Institutions that most need help'are those that provide the greatest access to nontraditional and underprepared students in community colleges and less selective universities.

[Epidemiology and management of stroke patients in emergency departments of the Centre region of France]

INTRODUCTION

Stroke is a leading cause of death and disability. Patients with suspected stroke are usually managed in emergency departments (ED). Stroke units must be created in our country, but only few French epidemiological data are available to define needs in stroke care.

OBJECTIVE

A prospective study was planned to evaluate epidemiology and stroke care for patients with suspected stroke admitted in the 22 ED of our region in the center of France during a two-month period.

METHODS

Patients with suspected stroke seen at the 22 ED were prospectively followed until discharge or one month after admission. Data on demographic characteristics, mode of transport, delay of arrival and imaging, clinical findings at arrival, department of admission, diagnosis, Rankin scale at day 7, in-hospital mortality, and outcome at a month were collected. A global statistical analysis and a comparison between rural and urban ED were performed.

RESULTS

Five hundred and ninety-eight patients were included. Mean age was 75 years. Median admission delay was 4 hours and 52 minutes. Predominant mode of transport was a private ambulance. A CT scan was obtained in 91 p.cent of cases with a median delay of 2 hours and 30 minutes. Only a third of the patients were admitted in departments of Neurology. Final diagnosis was: ischemic stroke (61 p.cent), transient ischemic attack (16 p.cent), hemorrhagic stroke (10 p.cent), other vascular disease (3 p.cent), non vascular disease (10 p.cent). In-hospital mortality was 20 p.cent, factors significantly associated with death rate were elevated age and a Glasgow coma scale<10 at admission. Mean length of stay was 12 days for stroke patients. At one month, 63 percent of patients were discharged to their home, 28 percent were transferred to an institution or in a rehabilitation unit, and 15 percent were still hospitalized. Significant differences in stroke care were found between rural and urban ED.

CONCLUSION

This prospective study provides epidemiological data for our region. Creation of stroke units and definition of acute stroke networks are necessary to improve stroke care.

Vascular endothelial growth factor and basic fibroblast growth factor differentially modulate early postnatal coronary angiogenesis

The roles of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF [FGF-2]) in early postnatal regulation of coronary angiogenesis were investigated by administering neutralizing antibodies to these growth factors between postnatal days 5 and 12. Immunohistochemistry and Western blotting both revealed decreases in VEGF protein in the hearts of rats treated with either antibody. In contrast, bFGF mRNA increased in both treated groups, whereas VEGF mRNA was unchanged. Using stereological assessment of perfusion-fixed hearts, we found that both anti-VEGF and anti-bFGF inhibited the rapid and marked capillary growth that occurs during this time period and that the effects of the two neutralizing antibodies are not additive. Arteriolar growth, as indicated by a lower length density, was inhibited by anti-bFGF, but not anti-VEGF. When both anti-VEGF and anti-bFGF were administered, arteriolar length density was not significantly lower, but the population of small arterioles (<15 microm) was markedly reduced, whereas the percentage of large arterioles (26 to 50 microm) more than doubled. Thus, inhibition of both growth factors negated or limited the formation of small arterioles and facilitated an expansion of the largest arterioles. These in vivo data are the first to document that during the early neonatal period, (1) both VEGF and bFGF modulate capillary growth, (2) bFGF facilitates arteriolar growth, and (3) the two growth factors interact to establish the normal hierarchy of the arteriolar tree.

Discovery of TBC11251, a potent, long acting, orally active endothelin receptor-A selective antagonist

Previously we reported the discovery of amidothiophenesulfonamides as endothelin receptor-A antagonists with high potency and selectivity. Replacement of an amide group in this class of compounds with an acetyl group maintained the in vitro binding affinity and in vivo activity while providing a compound with oral bioavailability and longer duration of action. The optimal compound discovered during these studies, 15q (TBC11251), binds competitively to human ETA receptors with a Ki of 0.43 +/- 0.03 nM and an IC50 of 1.4 nM (IC50 for ETB = 9800 nM). This compound inhibits ET-1-induced stimulation of phosphoinositide turnover with a Ki of 0.686 nM and a pA2 of 8.0. The compound has a serum half-life in the rat and the dog of 6-7 h and 60-100% oral bioavailability. This compound is one of the most selective ETA antagonists reported and therefore is suitable for additional pharmacological and clinical investigation of the role of ETA receptors in diseases.

Odontogenic keratocysts of the midline maxillary region

PURPOSE

This article compares the demographic features of the anterior midline maxillary odontogenic keratocyst with those in other regions.

MATERIALS AND METHODS

The data on 18 cases of anterior midline maxillary odontogenic keratocyst were reviewed.

RESULTS

Thirteen of the cases were in men (72.2%), and 16 of the patients (88.9%) were past the age of 60 years. The mean age of the patients was 69.9 years, which is much higher than for odontogenic keratocysts in other locations. The most common clinical diagnoses were periapical cyst and nasopalatine duct cyst.

CONCLUSION

It is important to include odontogenic keratocyst in the differential diagnosis of anterior midline maxillary radiolucencies, especially when they occur in older individuals.

Translocation of cytosolic phospholipase A2 to the nuclear envelope elicits topographically localized phospholipid hydrolysis

Cytosolic phospholipase A2 (cPLA2) is a good candidate for mediating the agonist-stimulated release of arachidonic acid (AA) from membrane phospholipids. This enzyme undergoes a Ca(2+)-dependent translocation from the cytosol to a membrane site in a variety of cell types, and this site has recently been identified as the nuclear envelope in leucocytes. The functional correlate of this finding has not yet been established. The present study was therefore undertaken to determine whether translocation of cPLA2 to the nuclear envelope was associated with localized phospholipid hydrolysis at this site. Rat alveolar epithelial cells, previously shown to contain cPLA2, were prelabelled with [3H]AA and stimulated with the model agonist, ionophore A23187. Ionophore-induced AA release exhibited characteristics typical of a cPLA2-mediated response, in that it was Ca(2+)-dependent, sn-2 AA-selective, and inhibited by arachidonyl trifluoromethyl ketone. As determined by indirect immunofluorescence microscopic analysis as well as subcellular fractionation with immunoblotting, ionophore treatment resulted in a translocation of cPLA2 protein from the cytoplasm to the nuclear envelope. To determine whether the nuclear membrane was indeed the source of released AA, prelabelled cells were incubated in the presence or absence of A23187, after which the phospholipid radioactivity was quantified in nuclear and non-nuclear membrane fractions. [3H]AA was distributed in both nuclear and non-nuclear membrane phospholipids. Following A23187 stimulation, the loss of [3H]AA from nuclear membrane phospholipids accounted for 88.1 +/- 5.8% of the total loss from phospholipids and for 92.9 +/- 2.3% of the total [3H]AA released into the medium. These results demonstrate for the first time that agonist-stimulated translocation of cPLA2 to the nuclear envelope is associated with phospholipid hydrolysis which is preferentially localized to that site.

Liver transplantation: dentistry is an essential part of the team

Liver transplantation has become a commonplace procedure, with more than 3,000 livers being transplanted annually. Patient demand remains much greater than availability of donor organs, resulting in many deaths per year. Due to the nature of hepatic function, unique concern exists regarding susceptibility to infection and rejection during the post-transplant period, placing great importance on vigilant oral health maintenance. Patients are severely immunocompromised and must be well educated and treated pretransplant and for the rest of their post-transplant lives; however, even though patients are on waiting lists for matching donor livers for an adequate amount of time to provide definitive dental treatment, this is not a major priority on the protocols of some transplant centers. This paper addresses these concerns and illustrates a patient who presented shortly post-transplant with severe dental problems requiring immediate definitive treatment. As these patients may present in any office, general dentists should be aware of the unique concerns involving their assessment, education, treatment and maintenance.

Epidermal growth factor stimulates vascular endothelial growth factor production by human malignant glioma cells: a model of glioblastoma multiforme pathophysiology

Hypervascularity, focal necrosis, persistent cerebral edema, and rapid cellular proliferation are key histopathologic features of glioblastoma multiforme (GBM), the most common and malignant of human brain tumors. By immunoperoxidase and immunofluorescence, we definitively have demonstrated the presence of vascular endothelial growth factor (VEGF) and epidermal growth factor receptor (EGFr) in five out of five human glioma cell lines (U-251MG, U-105MG, D-65MG, D-54MG, and CH-235MG) and in eight human GBM tumor surgical specimens. In vitro experiments with glioma cell lines revealed a consistent and reliable relation between EGFr activation and VEGF production; namely, EGF (1-20 ng/ml) stimulation of glioma cells resulted in a 25-125% increase in secretion of bioactive VEGF. Conditioned media (CM) prepared from EGF-stimulated glioma cell lines produced significant increases in cytosolic free intracellular concentrations of Ca2+ ([Ca2+]i) in human umbilical vein endothelial cells (HUVECs). Neither EGF alone or CM from glioma cultures prepared in the absence of EGF induced [Ca2+]i increases in HUVECs. Preincubation of glioma CM with A4.6.1, a monoclonal antibody to VEGF, completely abolished VEGF-mediated [Ca2+]i transients in HUVECs. Likewise, induction by glioma-derived CM of von Willebrand factor release from HUVECs was completely blocked by A4.6.1 pretreatment. These observations provide a key link in understanding the basic cellular pathophysiology of GBM tumor angiogenesis, increased vascular permeability, and cellular proliferation. Specifically, EGF activation of EGFr expressed on glioma cells leads to enhanced secretion of VEGF by glioma cells. VEGF released by glioma cells in situ most likely accounts for pathognomonic histopathologic and clinical features of GBM tumors in patients, including striking tumor angiogenesis, increased cerebral edema and hypercoagulability manifesting as focal tumor necrosis, deep vein thrombosis, or pulmonary embolism.

P300 from auditory and somatosensory stimuli: probability and inter-stimulus interval

The P300 (P3) event-related brain potential (ERP) was elicited with auditory and somatosensory stimuli using an easy discrimination task in two experiments. Experiment 1 manipulated target stimulus probability (0.20 vs. 0.80). Experiment 2 manipulated inter-stimulus interval (2 s vs. 6 s) for both stimulus modalities in different conditions while keeping target probability constant. Probability and inter-stimulus interval had similar effects for auditory and somatosensory stimuli, with lower probability and longer inter-stimulus intervals producing larger P3 amplitudes. No statistically reliable differences in scalp distribution between modalities were obtained, with both modalities producing maximal amplitudes at Pz. The results suggest that auditory and somatosensory stimuli when used in a relatively easy discrimination task yield the same overall P3 values.

High-volume enzyme immunoassay test system for sulfamethazine in swine

A high-volume enzyme immunoassay (EIA) system for slaughterhouse screening of sulfamethazine in swine plasma/serum has been developed. The system includes a robotic sample processor that performs most of the liquid handling requirements in the assay. The assay gives good correlation with the widely used thin layer chromatographic method for determination of sulfamethazine in serum and plasma (r = 0.826). Inter- and intra-assay coefficients of variation are less than 10%. Approximately 2,400 serum/plasma samples can be analyzed in a normal working day (8 h) with this system.

Augmented desensitization to epidermal growth factor (EGF) immediate actions: a novel mechanism for altered EGF growth response in mutant A431 cells

Epidermal growth factor (EGF) may either stimulate or inhibit cell growth. To elucidate the mechanism of these varied effects, we compared EGF action in parental A431 cells in which cell growth is inhibited, and clone 15, a mutant of these cells resistant to EGF growth inhibition. In both lines, EGF receptor was present in similar concentrations and underwent tyrosine phosphorylation to the same extent. Likewise, in both lines, acute exposure to EGF stimulated an increase in free cytoplasmic [Ca2+], as well as a similar increase in phosphorylation of lipocortin 1, a major substrate for the EGF receptor kinase whose phosphorylation is calcium-dependent. On the other hand, pretreatment of clone 15 cells with EGF for 72 h abolished EGF-induced phosphorylation of lipocortin 1 and led to a loss of the increase in cytoplasmic free [Ca2+], whereas no such desensitization was seen in the parental A431 cells. These data indicate a link between EGF-induced increase in cytoplasmic calcium, lipocortin phosphorylation, and cell growth and suggest that differences in mechanisms of desensitization to these immediate actions of EGF may lead to altered growth response to this hormone.

Role of cyclic AMP in rat aortic microsomal phosphorylation and calcium uptake

The role of adenosine 3',5'-monophosphate (cyclic AMP)-dependent membrane phosphorylation in the regulation of microsomal calcium transport in rat aortic smooth muscle was studied. Cyclic AMP-dependent protein kinase augmented the phosphorylation of serine residues in a microsomal protein component with a molecular weight of about 44,000 (determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis) and the majority of 32P incorporation was in serine residue(s). The phosphorylated protein had stability characteristics of a phosphoester. The phosphorylated substrate was not extracted from the trichloroacetic acid (TCA) precipitate with organic solvents or by suspension in hot TCA; and the demonstrated hydroxylamine insensitivity suggested that the substrate was not lipid or nucleic acid. Intrinsic phosphoprotein phosphatase cleaved the labeled phosphate from the cyclic AMP-stimulated microsomes in the first 5 min of incubation. Microsomes phosphorylated in the presence of 1 micron cyclic AMP or 1 micron cyclic AMP plus 0.1 mg/ml protein kinase exhibited enhanced calcium uptake. We suggest that reversible phosphorylation of microsomal membranes may play an important role in the regulation of aortic microsomal calcium transport by cyclic AMP.