Transitional care programs for trauma patients: A scoping review

BACKGROUND

Transitional care programs establish comprehensive outpatient care after hospitalization. This scoping review aimed to define participant characteristics and structure of transitional care programs for injured adults as well as associated readmission rates, cost of care, and follow-up adherence.

METHODS

We conducted a scoping review in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews standard. Information sources searched were Medline, the Cochrane Library, CINAHL, and Scopus Plus with Full Text. Eligibility criteria were systematic reviews, clinical trials, and observational studies of transitional care programs for injured adults in the United States, published in English since 2000. Two independent reviewers screened all full texts. A data charting process extracted patient characteristics, program structure, readmission rates, cost of care, and follow-up adherence for each study.

RESULTS

A total of 10 studies described 9 transitional care programs. Most programs (60%) were nurse/social-worker-led post-discharge phone call programs that provided follow-up reminders and inquired regarding patient concerns. The remaining 40% of programs were comprehensive interdisciplinary case-coordination transitional care programs. Readmissions were reduced by 5% and emergency department visits by 13% among participants of both types of programs compared to historic data. Both programs improved follow-up adherence by 75% compared to historic data.

CONCLUSION

Transitional care programs targeted at injured patients vary in structure and may reduce overall health care use.

The gap between hospital-based violence intervention services and client needs: A systematic review

BACKGROUND

Survivors of intentional interpersonal violence face social challenges related to social determinants of health that led to their initial injury. Hospital-based violence intervention programs reduce reinjury. It is unclear how well they meet clients' reported needs. This systematic review aimed to quantify how well hospital-based violence intervention program services addressed clients' reported needs.

METHODS

Medline, The Cochrane Library, CINAHL Plus with Full Text, and PsycInfo were queried for studies addressing hospital-based violence intervention programs services and intentional injury survivors' needs in the United States. Case reports, reviews, editorials, theses, and studies focusing on pediatric patients, victims of intimate partner violence, or sexual assault were excluded. Data extracted included program structure, hospital-based violence intervention program services, and client needs assessments before and after receiving hospital-based violence intervention program services.

RESULTS

Of the 3,339 citations identified, 13 articles were selected for inclusion. Hospital-based violence intervention programs clients' most reported needs included mental health (10 studies), employment (7), and education (5) before receiving hospital-based violence intervention programs services. Only 4 studies conducted quantitative client needs assessments before and after receiving hospital-based violence intervention program services. All 4 studies were able to meet at least 50% of each of the clients' reported needs. The success rate depended on the need and program location: success in meeting mental health needs ranged from 65% to 90% of clients. Conversely, time-intensive long-term needs were least met, including employment 60% to 86% of clients, education 47% to 73%, and housing 50% to 71%.

CONCLUSION

Few hospital-based violence intervention programs studies considered clients' reported needs. Employment, education, and housing must be a stronger focus of hospital-based violence intervention programs.

Gender Disparities and Differences Among Urologists Included in Top Doctor Lists

OBJECTIVE

To understand gender trends among urologists included in "Top Doctor" lists as more women practice urology, we (1) Evaluated whether Top Doctor lists reflect a contemporary distribution of urologists by gender; (2) Describe regional differences in gender composition of lists; (3) Report similarities and differences among men and women Top Doctors.

METHODS

All urologists in regional Top Doctor Castle Connolly lists published in magazines between January 1, 2020 and June 22, 2021 were included. Physician attributes were abstracted. American Urological Association (AUA) census data was used to compare the number of men and women Top Doctor urologists to the number of practicing men and women urologists within each list's zip codes. Log odds ratios (OR) and (95% confidence intervals) were used to compare likelihood of list inclusion by gender overall and by region.

RESULTS

Four hundred and ninety-four Top Doctor urologists from 25 lists were analyzed, of which 42 (8.50%) were women. Women urologists comprised 0%-27.8% of each list, with 7 lists (28.0%) including zero women urologists. Using AUA census data, OR for list inclusion of men urologists compared to women was 1.31 (1.01, 1.70) overall, with OR = 0.78 (0.36, 1.72) in the West, OR = 1.39 (1.03, 1.89) South, OR = 1.46 (0.8, 2.67) Northeast, OR = 1.90 (0.50, 7.18) Midwest. Women top urologists completed fellowship more often than men (66.7%, 55.1%) and were significantly more likely to complete female pelvic medicine and reconstructive surgery (FPMRS) fellowship (P <.001).

CONCLUSION

Men urologists were significantly more likely to be included in Top Doctor lists than women urologists. Top women urologists were significantly more likely to complete FPMRS fellowship.

National evaluation of the association between stay-at-home orders on mechanism of injury and trauma admission volume

BACKGROUND

The COVID-19 pandemic had numerous negative effects on the US healthcare system. Many states implemented stay-at-home (SAH) orders to slow COVID-19 virus transmission. We measured the association between SAH orders on the injury mechanism type and volume of trauma center admissions during the first wave of the COVID-19 pandemic.

METHODS

All trauma patients aged 16 years and older who were treated at the American College of Surgeons Trauma Quality Improvement Program participating centers from January 2018-September 2020. Weekly trauma patient volume, patient demographics, and injury characteristics were compared across the corresponding SAH time periods from each year. Patient volume was modeled using harmonic regression with a random hospital effect.

RESULTS

There were 166,773 patients admitted in 2020 after a SAH order and an average of 160,962 patients were treated over the corresponding periods in 2018-2019 in 474 centers. Patients presenting with a pre-existing condition of alcohol misuse increased (13,611 (8.3%) vs. 10,440 (6.6%), p <0.001). Assault injuries increased (19,056 (11.4%) vs. 15,605 (9.8%)) and firearm-related injuries (14,246 (8.5%) vs. 10,316 (6.4%)), p<0.001. Firearm-specific assault injuries increased (10,748 (75.5%) vs. 7,600 (74.0%)) as did firearm-specific unintentional injuries (1,318 (9.3%) vs. 830 (8.1%), p<0.001. In the month preceding the SAH orders, trauma center admissions decreased. Within a week of SAH implementation, hospital admissions increased (p<0.001) until a plateau occurred 10 weeks later above predicted levels. On regional sub-analysis, admission volume remained significantly elevated for the Midwest during weeks 11-25 after SAH order implementation, (p<0.001).

Internet of things platform technology used in undergraduate nursing student education: a scoping review protocol

INTRODUCTION

Future nursing education needs to build a cutting-edge technology-based educational environment to provide a variety of consumer-oriented education. Thus, the sharing of information in nursing education needs to be considered, especially given the advancement of internet of things (IoT) technology. Before developing a horizontal platform, understanding previously developed IoT platforms is necessary to establish services and devices compatible with each other in different service areas. This scoping review aims to explore the technology used in the IoT platform for the education of nursing students in the undergraduate nursing curriculum.

METHODS AND ANALYSIS

A preliminary search was completed to find initial search terms, on which a full-search strategy was developed. Search results yielded from PubMed (NCBI) were screened to ensure articles were peer-reviewed, published in English from January 1999 to August 2021, and relevant to developing, applying and evaluating IoT platforms at educational institutions for students in undergraduate nursing programmes. A full-text review of relevant articles will be conducted, and data will be extracted using the developed extraction tool. The extracted qualitative data will be analysed using a modified grounded theory approach, informing a working definition of the IoT platform and related terms.

ETHICS AND DISSEMINATION

The study was exempted from ethical review by the Institutional Review Board of Nambu University, South Korea. Study results will be disseminated through peer-reviewed journals.

Can electrocoagulation process be an appropriate technology for phosphorus removal from municipal wastewater?

This paper evaluated a novel pilot scale electrocoagulation (EC) system for improving total phosphorus (TP) removal from municipal wastewater. This EC system was operated in continuous and batch operating mode under differing conditions (e.g. flow rate, initial concentration, electrolysis time, conductivity, voltage) to evaluate correlative phosphorus and electrical energy consumption. The results demonstrated that the EC system could effectively remove phosphorus to meet current stringent discharge standards of less than 0.2mg/L within 2 to 5min. This target was achieved in all ranges of initial TP concentrations studied. It was also found that an increase in conductivity of solution, voltages, or electrolysis time, correlated with improved TP removal efficiency and reduced specific energy consumption. Based on these results, some key economic considerations, such as operating costs, cost-effectiveness, product manufacturing feasibility, facility design and retrofitting, and program implementation are also discussed. This EC process can conclusively be highly efficient in a relatively simple, easily managed, and cost-effective for wastewater treatment system.

Remediation potential of mulch for removing lead

Hardwood bark mulch has good physicochemical properties for the adsorption of lead (Pb(II)). Batch tests were conducted to obtain the sorption coefficient of Pb(II) in mulch. The results of the Freundlich model were not in as good agreement as for the case of the Langmuir model. In addition, a laboratory-scale mulch permeable reactive barrier (PRB) system was designed for the treatment of Pb(II)-contaminated groundwater. The mulch PRB system, using a mulch layer, can potentially be used in the subsurface for cost-effective and in situ transformation of the Pb(II) into environmentally acceptable forms. From the Pb(II) breakthrough curve, the mulch becomes saturated more quickly at higher flow rates.

Development of polymer lab-on-a-chip (LOC) for oxidation-reduction potential (ORP) measurement

Reverse osmosis (RO) desalination has been recognized as a promising method to solve the water shortage problem. Nevertheless, since it is energy intensive and has many problems associated with biofouling/fouling of RO membranes in RO plants, its commercial acceptance is still slow. Especially, as high levels of oxidizing agents negatively affect RO membrane efficiency and life span. So, there is a need to develop sensitive, selective, portable and rapid methods to determine oxidation-reduction potential (ORP) in feed solution. For developing a polymer ORP lab-on-a-chip (LOC), a microchannel patterned on a polymer substrate was successfully filled with 800 nm diameter silica beads using self-assembly bead packing technology. The measured ORPs using the three kinds of redox potential solutions were typically slightly lower than those of the nominal redox potential. But, all of the measurements should be deemed acceptable. The ORP LOC has also a much shorter response time than the conventional potentiometric sensor.

Utilization of house fly-maggots, a feed supplement in the production of broiler chickens

Recent studies have suggested the utilization of maggots as a feed supplement forenhanced broiler performance. Maggots, which are a major dietary source of protein, appear during the biodegradation of chicken droppings using house flies. The objective ofthe present study was to investigate the effect of maggot supplementation on the meat quality and growth performance of broiler chickens. A total of 600 one-day-old male commercial broiler chicks (Ross) were randomly assigned into 5 treatment groups consisting of 40 replicates of 3 birds. The birds were fed either a basal diet or the basal diet supplemented with 5.0, 10.0, 15.0 and 20.0% maggots. Overall, broiler chicken performance was influenced by the optimal amino acid profile; high protein (63.99%) and essential amino acid content (29.46%), or high protein digestibility (98.50%) of the maggots. Maggot supplementation caused linear increases in live weight gain but not the feed conversion ratio. The diets of 10 and 15% maggots was the most efficient in terms of average weight gain forthe 4-5 week old broiler chickens (p<0.05). It also significantly increased dressing percentage, breast muscle, and thigh muscle (p<0.05). No differences were observed forliver abdominalfat, or meat color, and the crude protein contents of breast muscle were constant. However, in the maggot-fed broilers, breast muscle lysine and tryptophan levels increased significantly as compared to the birds fed the basal diet (p<0.05). These results indicate that feeding diets containing 10 to 15% maggots in chicken dropping after biodegradation can improve the carcass quality and growth performance of broiler chickens.

Development of a portable analyzer with polymer lab-on-a-chip (LOC) for continuous sampling and monitoring of Pb(II)

A new portable analyzer with polymer lab-on-a-chip (LOC) has been designed, fabricated and fully characterized for continuous sampling and monitoring of lead (Pb(II)) in this work. As the working electrodes of the sensor, bismuth (Bi (III)) which allowed the advantage of being more environmentally friendly than traditional mercury drop electrodes was used, while maintaining similar sensitivity and other desirable characteristics. The size of a portable analyzer was 30 cmx23 cmx7 cm, and the weight was around 3 kg. The small size gives the advantage of being portable for field use while not sacrificing portability for accuracy of measurement. Furthermore, the autonomous system developed in coordination with the development of new polymer LOC integrated with electrochemical sensors can provide an innovative way to monitor surface waters in an efficient, cost-effective and sustainable manner.

Antioxidative potential of raw breast meat from broiler chicks fed a dietary medicinal herb extract mix

This study was performed to evaluate the antioxidative potential and quality of the breast meat of broiler chickens fed a dietary medicinal herb extract mix (MHEM, consisting of mulberry leaf, Japanese honeysuckle, and goldthread at a ratio of 48.5:48.5:3.0). A total of 480 one-day-old male Cobb broiler chicks were randomly allotted to 12 pens, with 40 birds per pen (replicate), and reared for 35 d. Dietary treatments consisted of a corn-soybean meal basal diet (control); a basal diet with 0.3% MHEM (T1); and a basal diet with 1% (T2) MHEM. At the end of the feeding trial, breast meat samples were excised and stored in a refrigerator at 4 degrees C to be analyzed at d 0, 3, and 7. The MHEM did not affect proximate composition of the breast meat. Total phenols content of the breast meats in the T1 and T2 diets was approximately 2 times greater than that of the control diet (P < 0.05). 1,1-Diphenyl-2-picrylhy-drazyl radical-scavenging activity and 2,2-azinobis-(3 ethylbenzothiazoline-6-sulfonic acid) cation-reduction activity were greater in the T2 diet at d 0 and in the T1 diet at d 3 compared with the control diet (P < 0.05). 2-Thiobarbituric acid-reactive substance values in the T1 and T2 diets were lower than in the control diet at d 3 and 7 and did not increase during storage, whereas the value in the control diet increased significantly. The pH of the T1 diet was significantly greater than that of the control diet at d 0 and 3. In a sensory test, panelists preferred the T1 breast meat throughout the 7-d storage period. This research indicates that dietary MHEM could increase the antioxidative potential and overall preference of breast meat during cold storage.

Control of microorganisms and reduction of biogenic amines in chicken breast and thigh by irradiation and organic acids

The effect of irradiation or organic acid treatment of raw chicken breast and thigh meat to control inoculated microorganisms and the production of biogenic amines (BA) was studied. Bacillus cereus, Enterobacter cloacae, and Alcaligenes faecalis were selected and inoculated into raw ground chicken breast and thigh meat at approximately 10(7) cfu/g. The samples were irradiated at 0, 0.5, 1, and 2 kGy or mixed with a 0.2 M solution of acetic, citric, or lactic acid (1 mL for 10 g of meat sample) for 24 h at 4 degrees C. Viable cell counts and BA contents were determined. Irradiation was effective in reducing the inoculated bacteria: 0.5 kGy achieved approximately a 2-log reduction, and no viable cells were detected at a dose of 2 kGy. In contrast, only up to a 1-log reduction was achieved by organic acid treatment except for citric acid, which achieved approximately a 3-log reduction of E. cloacae. Both the irradiation and organic acid treatment of raw chicken breast and thigh reduced the BA content, but the rate of BA reduction differed by inoculated organism and treatment (irradiation or organic acid). Although irradiation was an excellent method for controlling inoculated microorganisms, the content of BA produced was similar to that of the organic acid treatment of raw chicken breast and thigh meat.

Phase II trial of imatinib mesylate in recurrent, biomarker positive, ovarian cancer (Southwest Oncology Group Protocol S0211)

Platinum-resistant ovarian cancer continues to be a difficult therapeutic problem. Clearly, molecularly targeted agents should be evaluated in this patient population. Patients were eligible for this phase II study with stage III or IV ovarian cancer, whose tumor expressed Kit (CD117) or platelet-derived growth factor receptor (PDGFR) and with relapse of measurable disease within 6 months of completing frontline, platinum- and taxane-based chemotherapy. Patients were treated daily with 400 mg of imatinib mesylate orally. It was assumed that the agent would be of no further interest if the population response rate was less than 10%. A two-stage design was used for patient accrual. A total of 34 patients were registered to the study. Of these, 15 were found to be ineligible or not evaluable (8 because their tumor samples were negative for both DC117 and PDGFR). Of 19 evaluable patients, 2 (11%) tested positively for c-Kit and 17 (89%) tested positively for PDGFR. There were no objective responders. Thirteen patients (68%) had increasing disease or symptomatic deterioration, and six (32%) went off protocol during the first month due to adverse events. Median progression-free survival was 2 months (95% CI 1-3 months) and median overall survival was 10 months (95% CI 6-18 months). Eleven percent of patients experienced grade 4 hematologic/metabolic toxicity and 37% experienced grade 3 nonhematologic toxicity. We conclude that imatinib mesylate as a single agent does not appear to have useful clinical activity in c-Kit and/or PDGFR positive, recurrent ovarian cancer in heavily pretreated patients with ovarian cancer.

Application of mulch for treating metals in urban runoff: batch and column test

Among the many methods available for the removal of heavy metals in urban nonpoint source pollution (NSP), adsorption has been shown to be an economically feasible alternative. To adsorb the amount of heavy metals in runoff, filtration of runoff through a specially constructed filter system is one possible treatment method. The mulch layer in a specially constructed filter system functions through adsorptive-filtration, where some pollutants are immobilised through sorption and some pollutants associated with suspended solids are immobilised through filtration. Therefore, the major interest of this study was to investigate the possibility of utilising mulch for the adsorption of heavy metals such as cadmium, copper, lead and zinc for a solution typical of those found in urban runoff using the flask-type adsorption batch tests and laboratory column tests. From the equilibrium sorption batch tests, it was observed that the adsorption of heavy metals on mulch with the same initial concentrations of metals in the solution decreased in the order Pb(II) > Cu(II) > Zn(II) > Cd(II) regardless of changes in pH. In column tests, the breakthrough curves for various heavy metals' adsorption by mulch showed that the binding strength of the following metal ions onto mulch was as follows: Pb(II) > Cu(II) > Zn(II) > Cd(II).

Effect of dissolved oxygen concentration on the biofilm and in situ analysis by fluorescence in situ hybridization (FISH) and microelectrodes

A better understanding of microbiology and ecology of nitrifying bacteria in inner biofilms is an important part of improving process performance and control. Microelectrodes and fluorescent in situ hybridization (FISH) in biofilm research have been used to investigate the spatial distributions of various microbial activities in biofilms and have led to new experimental findings as well as modifications of the homogeneous assumptions in the biofilm kinetic models. The objective of this study is to try the combination of two methods, both FISH and microelectrode measurements, and to provide reliable and in situ information on nitrifying bacterial activity in biofilms. The characteristics of biofilm developed on tygon slides were different according to the change of dissolved oxygen (DO). When the DO increased from 2 to 10 mg DO/L, the rate of the biofilm thickness increased and its dry density changed from 50-70 to 25-90 mg/cm3. Ammonia oxidizing bacteria were not uniformly distributed in biofilm, and were found at the deeper layer where oxygen is depleted, they were detected primarily in the upper and middle layers of the biofilm.

pH, hypoxia and metastasis

The vascular supply to tumours is often poorly formed and irregular with the result that tumours may contain regions of poor nutritional supply with hypoxia and acidic pH. Clinical studies have demonstrated substantial heterogeneity in oxygenation in human tumours. In some studies tumours with poorer oxygenation were more likely to have metastasized. In our studies of carcinoma of the cervix, nodal metastases were 1.5 times more likely at diagnosis in patients with more hypoxic tumours relative to those with less hypoxic tumours. Transplanted rodent KHT fibrosarcomas and SCC-VII squamous cell tumours also have variability in levels of oxygenation; again, the more hypoxic tumours are found to be more metastatic. Furthermore, deliberate exposure of KHT tumours to cyclic hypoxia (12 cycles of 5% oxygen breathing for 10 min interspersed with 10 min air breathing) every day during their growth, doubled the level of micrometastases that were detected in the lungs of the mice. These findings are consistent with in vitro studies demonstrating that KHT and SCC-VII cells and B-16 melanoma cells exposed to hypoxia or low pH have increased propensity to form metastases following injection into-mice. This effect is transient and is lost within about 48 h of removal of exposure to hypoxia or low pH, suggesting that the effect may be due to changes in gene expression associated with that stress. Recent studies have implicated a number of genes, such as vascular endothelial growth factor and interleukin 8, in the effect of hypoxic and acid pH on metastasis.

Effect of heavy metals (Cu, Pb, and Ni) on the compositions of EPS in biofilms

A series of batch adsorption tests to estimate the biofilm capacity for removal of the heavy metals (Cu, Pb, and Ni) in wastewater were carried out. The metal sorption results were fitted to the Freundlich isotherm model to compare their sorption capacity. The change of the composition of EPSs (extracellular polymeric substances) was simultaneously represented by the ratio of carbohydrate to protein (C/P) when the biofilm was exposed to the heavy metals. EPS composed of slime loosely bound to the cell and capsular materials was extracted by the four general extraction methods including regular centrifugation, regular centrifugation with formaldehyde, EDTA extraction and steam extraction. Although the various extraction methods showed different results, C/P ratio of biofilm exposed to copper and lead metal ions was generally lower than that of control.

Expression of constitutively active phosphatidylinositol 3-kinase inhibits activation of caspase 3 and apoptosis of cardiac muscle cells

Apoptosis of cardiac muscle cells contributes to the development of cardiomyopathy. Recent studies showed that insulin-like growth factor I (IGF-I) inhibits apoptosis of cardiac muscle cells and improves myocardial function in experimental heart failure. This study was carried out to elucidate the role of phosphatidylinositol 3-kinase (PI 3-kinase) in the anti-apoptotic actions of IGF-I in cardiomyocytes and to explore whether expression of constitutively active PI 3-kinase can inhibit apoptosis in cardiomyocytes. Apoptosis of primary cardiomyocytes was induced by doxorubicin treatment and serum withdrawal. Transduction of cardiomyocytes with constitutively active PI 3-kinase specifically lead to serine phosphorylation of Akt, whereas phosphorylation of IGF-I receptor, IRS1/2 and p44/42 mitogen-activated protein kinase were not increased. In the cardiomyocytes transduced with constitutively active PI 3-kinase, activation of the pro-apoptotic caspase 3 was attenuated and fragmentation of DNA was reduced. Preincubating cells with PI 3-kinase inhibitor LY294002 was associated with loss of anti-apoptotic actions of IGF-I and PI 3-kinase. Neither IGF-I nor constitutively active PI 3-kinase lead to serine phosphorylation of Bad, suggesting that the anti-apoptotic effects of PI 3-kinase are not mediated through Bad phosphorylation in cardiac muscle cells. To determine whether activation of caspase 3 is sufficient to induce apoptosis in cardiomyocytes, an engineered TAT-caspase 3 protein was introduced to cardiomyocytes. Significant reduction of cell viability occurred in the cardiomyocytes transduced with active caspase 3, indicating that activation of caspase 3 is sufficient to cause cardiomyocyte death. These findings indicate the existence of an IGF-I receptor-PI 3-kinase-caspase 3 pathway in cardiomyocytes that plays an important role in the anti-apoptotic actions of IGF-I in heart. Moreover, these data suggest that modulation of PI 3-kinase activities may represent a potential therapeutic strategy to counteract the occurrence of apoptosis in cardiomyopathy.

Gene expression in individual cells: analysis using global single cell reverse transcription polymerase chain reaction (GSC RT-PCR)

The determination of the gene expression pattern of single cells has important implications for many areas of cellular and developmental biology including lineage determination, identification of primitive stem cells and temporal gene expression patterns induced by changes in the cellular microenvironment. Global Single Cell Reverse Transcription-Polymerase Chain Reaction (GSC RT-PCR) enables the study of single cell gene expression patterns. Initial observations of significant heterogeneity among single cells derived from a population of cells prompted us to determine how much of this observed heterogeneity was due to the intrinsic variation within the method. In this paper we discuss the sensitivity of GSC RT-PCR for analysis of differences in gene expression between single cells and, in particular, detail the amount of variation generated by the method itself. We found that most of the intrinsic variation in the method occurred in the PCR step. The total variation induced by the method was in the range of 5 fold. While we have determined that there is a five fold methodological variation in GSC RT-PCR, any method which use its components (including generation of cDNAs for microarray analysis) is likely to be affected by such experimental variability, which could limit the interpretation of the resulting data.

Radioresistant MTp53-expressing rat embryo cell transformants exhibit increased DNA-dsb rejoining during exposure to ionizing radiation

Recent data suggest that aberrant function of the wild type p53 protein (WTp53) may alter cellular survival following DNA damage through cellular pathways involving apoptosis and cell-cycle checkpoints, but little is known concerning it's possible role in DNA repair. In the present study, the ionizing radiation sensitivity was determined for a series of rat embryo fibroblast (REF) cell lines transfected with an activated form of the H-ras oncogene alone, or in combination with a variety of missense-mutant p53 (MTp53) alleles. Transformed REF clones which expressed exogenous MTp53 and p21ras proteins (CLASS II clones) were generally radioresistant in culture as determined by higher values for the surviving fraction after 2 Gy (SF2 value) and the radiation dose required to reduce survival to a fraction of 0.1 (D10 value), compared either to transformed REF clones expressing p21ras protein alone (CLASS I clones), or to non-transfected REF control cell lines expressing baseline endogenous levels of p21ras and WTp53 protein. The increased radioresistance observed in the CLASS II clones (following both HDR- and LDR-irradiation), was significantly correlated with increased expression of MTp53 protein, and a decreased radiation-induced G1 arrest response. The variability observed in clonogenic radiosensitivity among REF clones was not explained by differential radiation-induced apoptosis. Using the Comet assay performed after continuous low dose-rate (LDR)-irradiation, MTp53-expressing REF clones were also found to be more proficient at the rejoining of DNA double-strand breaks (DNA-dsb), compared to WTp53-expressing REF clones. These results suggest that an enhanced DNA and cellular repair capacity may, in part, explain the increased radiation survival observed in some MTp53-expressing transformed fibroblasts and tumours.

An examination of the effects of hypoxia, acidosis, and glucose starvation on the expression of metastasis-associated genes in murine tumor cells

Tumor cells exposed to a growth stress such as low pH, glucose starvation and hypoxia have been shown to exhibit a transient increase in experimental metastatic potential, particularly when allowed to recover under normal growth conditions for a period of 24-48 h. In this study we examined whether this increase in metastatic ability could be explained by changes in the expression of a number of different metastasis-associated genes, when the cells were exposed to similar conditions (24-48 h exposure to the stress condition followed by 0-48 h recovery under normal growth conditions). Although the cell lines used (KHT fibrosarcoma, SCC VII squamous cell carcinoma, and B16F1 melanoma) demonstrated altered metastatic ability after the treatment, no overall temporal correlation between changes in the mRNA levels for cathepsin B, cathepsin L, nm23, TIMP-1, osteopontin, or VEGF and metastatic ability in the three cell lines was observed. The production of gelatinase A (72 kDa collagenase) and gelatinase B (92 kDa collagenase) was also measured by gelatin zymography. There was an increase in production of these enzymes with increasing recovery time, but it did not parallel changes in metastatic potential. Although these results suggest that the products of most of the genes studied may not be involved in the transient metastatic changes, further studies are required to establish whether changes in protein levels track with changes in mRNA levels for these genes.

Mutator phenotype in Msh2-deficient murine embryonic fibroblasts

Embryonic fibroblast cell lines were established from mice deficient, heterozygous, or proficient for Msh2, one of the three known DNA mismatch repair genes involved in hereditary nonpolyposis colon cancer (HNPCC). Cell lines were established by transfection of primary mouse embryo fibroblasts with E7 and Ras oncogenes or mutant p53. Spontaneously immortalized cells derived from the primary cultures were also studied. To determine whether these cells developed a mutator phenotype similar to that found in colon cancer cells deficient in mismatch repair, we measured mutation rates, microsatellite instability, and sensitivities to a range of DNA-damaging agents. The mutator phenotype detected in the E7 and Ras or mutant p53-immortalized Msh2-/- mouse cells was similar to that found in human mismatch repair-deficient colorectal carcinoma cell lines. Mutation rates to ouabain resistance were increased 8-12-fold relative to lines from Msh2+/+ mice, and microsatellite instability was detectable in 12-18% of subclones derived from the Msh2-/- line but was undetectable in subclones developed from the Msh2+/+ line. Furthermore, E7 and Ras or spontaneously immortalized Msh2-/- cells were significantly more resistant to the cytotoxic effects of 6-thioguanine relative to Msh2+/+ cells. In contrast, these lines showed various responses to UV light and cis-platinum, suggesting that mismatch repair deficiency was not the sole determinant for sensitivity to these DNA-damaging agents. Particular attention was paid to the properties of cells heterozygous for the Msh2 mutant gene, which would mimic the situation of an HNPCC carrier. However, our studies failed to reveal any properties of these cells that might provide a growth advantage or predispose them for the acquisition of further mutations. This observation is consistent with the model that inactivation of the wild-type Msh2 allele is a critical step for tumorigenesis in HNPCC patients.

Exposure to hypoxia, glucose starvation and acidosis: effect on invasive capacity of murine tumor cells and correlation with cathepsin (L + B) secretion

Cells in tumors may be exposed to adverse conditions such as nutrient deprivation, acidic pH and hypoxia. It has been shown previously that exposure to hypoxia, acidosis and glucose starvation in vitro increases the experimental metastatic ability of murine KHT-LP1 sarcoma, SCC-VII squamous carcinoma and B16 melanoma cells. This effect was most marked when cells were allowed to recover under normal in vitro growth conditions before injection. In the present study we examined whether the invasive capacity of the cells could be influenced by these modifications of the cell microenvironment. We used Matrigel, a basement membrane-like preparation in a two-chamber invasion assay to address this issue. Both KHT-LP1 and SCC-VII murine cell lines showed an increased ability to invade through Matrigel after hypoxia, and glucose starvation, but there was no consistent change in invasive capacity following acidosis exposure. The results for hypoxia and glucose starvation are in agreement with our previous studies of metastatic ability for these cell lines and we confirmed this for KHT-LP1 cells exposed to hypoxia in the current study. In parallel with the invasion assays, we compared cathepsin (L + B) content of the cells in treated and control suspensions. The effect observed varied according to the cell line and the treatment received (hypoxia, glucose starvation). There was an increase of cathepsin content for KHT-LP1 cells exposed to hypoxia and this increase correlated well with the increase of the invasion ability through Matrigel. We did not observe any increase of cathepsin for hypoxia-treated SCC-VII or for KHT-LP1 and SCC-VII cells treated with glucose starvation. These results suggest that transient hypoxia and glucose starvation can increase the invasive ability of tumor cell lines and thus may cause tumor progression by facilitating the invasive step of the metastatic process. The increased levels of cathepsin (L + B) in the KHT-LP1 cells treated with hypoxia, compared to control non-treated cells, may play a part in this increased invasive capacity.

P53-mediated radioresistance does not correlate with metastatic potential in tumorigenic rat embryo cell lines following oncogene transfection

PURPOSE

Changes in wild-type p53 protein function occur in the majority of human tumors, and may alter genomic stability and the cellular response to ionizing radiation. Whether oncoproteins can render tumor cells both radioresistant and metastatic, may have implications for clinical strategies designed to improve local tumor control. In the studies reported here, we tested the hypothesis that acquired radioresistance correlates with metastatic potential within a large panel of transformed rat embryo cell (REF) lines following transfection with activated H-ras, mutant p53, and HPV16-E7 alleles.

METHODS AND MATERIALS

Rat embryo cells (REF cells) were transfected using the calcium-phosphate technique with an activated H-ras gene alone, or in combination with human papillomavirus HPV16-E7 and/or human or murine mutant p53 sequences. Other rat embryo cell clones expressing transfected HPV-E7 and activated ras sequences subsequently acquired endogenous p53 gene mutations during culture in vitro. The relative expression of p21ras and p53 protein for each REF transformant was determined by Western blot analysis following transfection. REF clones were phenotypically characterized at early passage (i.e., passages 5-7) and late passage (i.e., passages 10-20) for their: (a) relative tumor growth rate, and (b) their ability to undergo spontaneous metastasis following intramuscular injection into the hind legs of SCID mice. In vivo phenotypic end points were then compared to previously measured parameters of in vitro radiosensitivity for each cell line. Additionally, the expression of the cellular protease, plasminogen activator, was determined for a number of metastatic and nonmetastatic cell lines.

RESULTS

We found no evidence that selected oncogene-transfected REF transformants that were radioresistant in culture had a greater spontaneous metastatic potential than nonradioresistant REF transformants. Neither the level of expression of the p21ras protein nor that of the p53 protein was correlated with the spontaneous metastatic phenotype when tested at early passage. The metastatic phenotype appeared to be independent of p53 genotype. The majority of metastatic REF clones tested (7 out of 9 clones) expressed plasminogen activator following oncogene transfection, in contrast to nonmetastatic REF transformed cell lines.

CONCLUSIONS

Our results suggest that (a) intrinsic radioresistance does not correlate with spontaneous metastatic potential in oncogene-expressing REF transformant cell lines, and (b), novel clinical strategies designed to overcome oncogene-mediated radioresistance could potentially impact on overall survival, as gains in local tumor control may not be offset by a greater risk of distant metastasis.

Mutant p53 increases radioresistance in rat embryo fibroblasts simultaneously transfected with HPV16-E7 and/or activated H-ras

Recently, it has been suggested that abrogation of the wild type p53 protein function may alter the cellular response to DNA damaging agents, including ionizing radiation. This study was designed to compre the relative radiosensitivity and tumorigenicity of rat embryo fibroblast (REF) cell lines transfected with a mutant form of the p53 gene (plasmid MTp53pro193), alone, or in combination, with the H-ras (plasmid pEJ6.6) and HPV16-E7 (plasmid pJ4 omega 16.E7) oncogenes. Transfection of the mutant p53pro193 gene alone resulted in selected clones having increased radioresistance in culture which correlated with increased mutant p53 expression in these clones. However, the co-transfection of mutant p53 and H-ras genes or triple transfection of mutant p53, H-ras and E7 genes resulted in clones with high mutant p53 expression, significantly increased radioresistance and uniform tumorigenicity. There was no correlation between intrinsic radioresistance and spontaneous metastasis in the tumorigenic REF transfectant clones. Stepwise acquisition of radioresistance and an aggressive tumor cell phenotype is observed when the mutant p53 gene and HPV E7 co-operate with the ras oncogene in transfection assays, and can be correlated to increases in mutant p53 expression.

Drug sensitivity and metastatic ability in B16 melanoma cells

We have previously reported that highly metastatic cell lines derived from KHT fibrosarcoma (KHT 35L1) and B16 melanoma (B16F10) are more resistant to N-phosphonacetyl-L-aspartate (PALA) and methotrexate (MTX) than the parental cell lines. This correlation between drug resistance and metastatic ability suggested the possibility that both phenotypes might have arisen in parallel as a result of a similar mechanism. In this study, we examined this possibility by reproducing the selection procedure for B16F10 cells (by serial passage of B16F1 cells as lung nodules) and testing the cells at each passage for changes in resistance to PALA and MTX. The results confirm that serial passage of B16F1 cells as lung nodules (LP) selects for cells with increasing metastatic ability (100-fold after seven passages), but these cells did not develop increased resistance to PALA and became more sensitive to MTX. For comparison B16F1 cells were also serially passaged (six passages) as leg tumors (LT). These cells became slightly more metastatic (3-fold) than B16F1 cells maintained in tissue culture, and demonstrated a small increase in sensitivity to MTX, as in the LP lines. There was also an apparent increase in resistance to PALA. In no instance was there a parallel increase in drug resistance and metastatic ability indicating that these two phenotypes do not necessarily arise in parallel in this cell line.