Strategies for diversifying the pool of graduate students in biomedical sciences

As part of our National Cancer Institute-sponsored partnership between New Mexico State University and the Fred Hutchinson Cancer Research Center, we implemented the cancer research internship for undergraduate students to expand the pipeline of underrepresented students who can conduct cancer-related research. A total of 21 students participated in the program from 2008 to 2011. Students were generally of senior standing (47%), female (90 %), and Hispanic (85 %). We present a logic model to describe the short-, medium-, and long-term outputs of the program. Comparisons of pre- and post-internship surveys showed significant improvements in short-term outputs including interest (p<0.001) and motivation (p<0.001) to attend graduate school, as well as preparedness to conduct research (p=0.01) and write a personal statement (p=0.04). Thirteen students were successfully tracked, and of the nine who had earned a bachelor's degree, six were admitted into a graduate program (67 %), and four of these programs were in the biomedical sciences.

Long-term in vitro culture of hamster pancreatic β-cells and induction of adenocarcinoma by treatment with N-nitrosobis(2-oxopropyl)amine

OBJECTIVES

Earlier studies indicated that hamster pancreatic ductal adenocarcinoma not only derives from ductal/ductular structures but also from cells within the islet. So far unidentified cells within the islet are responsive to the carcinogenic effect of N-nitrosobis (2-oxopropyl) amine (BOP) forming poorly differentiated ductal adenocarcinoma. However, studies indicated a major role of β-cells during carcinogenesis. To find out, if β-cells are the primary target cells of BOP and if they are capable to form ductal adenocarcinoma after malignant transformation, we established a long-term culture of undifferentiated cells deriving from isolated β-cells and treated them with BOP.

METHODS

Langerhans' islets from pancreata of Syrian golden hamsters were isolated and dispersed into single cells by dispase digestion. Cells were labeled with a highly specific β-cell surface antibody (K14D10) and these K14D10+ cells were extracted from the suspension by paramagnetic Dynabeads. Cells were cultured in vitro and treated with BOP. Untreated cells served as control.

RESULTS

K14D10+ cells formed a monolayer and produced insulin over a period of 28 days in culture. However, with time in culture they became undifferentiated with a higher proliferation rate and after about 60 days in culture BOP treated cells showed anchorage independent growth. These cells autotransplanted s.c. formed a well-differentiated ductal adenocarcinoma.

CONCLUSIONS

Pancreatic β-cells are the primary target of BOP without necessarily being embedded in the compound of the Langerhans' islet. With time in culture, they give rise to undifferentiated cells and after malignant transformation they are able to form ductal adenocarcinoma.

Human mucosal CD4+ T cells but not blood CD4+ T cells respond vigorously towards CD28 engagement

Human lamina propria T lymphocytes (LPT) possess functional properties profoundly different from those of peripheral blood T lymphocytes (PBT). While they are characterized by a low proliferative response to T cell receptor (TCR)/CD3 stimulation in vitro their responsiveness to activation through the 'co-stimulatory' CD2-receptor is enhanced when compared to PBT. In this study, we demonstrate that engagement of another co-stimulatory receptor on both LPT and PBT, namely CD28, by a single monoclonal antibody (mAb), respectively, strongly activates the former but not the latter through a PI3-kinase dependent signalling pathway leading to the production of inflammatory cytokines such as interleukin (IL)-2, tumour necrosis factor (TNF)-α, interferon (IFN)-γ and granulocyte-macrophage colony-stimulating factor (GM-CSF). In addition to the high sensitivity of LPT to CD2 stimulation, this finding supports the notion that 'non-specific/innate' mechanisms to activate T lymphocytes play a predominant role vis-à-vis'TCR driven/adaptive' responses in the intestinal mucosa. Furthermore, it suggests that results from preclinical tests for therapeutic antibodies performed with human blood derived T cells are probably insufficient to predict reactivities of tissue-resident immune cells, which--given their quantitative predominance--may critically determine the in-vivo response to such compounds.

A randomised controlled pilot trial to evaluate and optimize the use of anti-platelet agents in the perioperative management in patients undergoing general and abdominal surgery--the APAP trial (ISRCTN45810007)

PURPOSE

Surgeons are increasingly confronted by patients on long-term low-dose acetylsalicylic acid (ASA). However, owing to a lack of evidence-based data, a widely accepted consensus on the perioperative management of these patients in the setting of non-cardiac surgery has not yet been reached. Primary objective was to evaluate the safety of continuous versus discontinuous use of ASA in the perioperative period in elective general or abdominal surgery.

METHODS

Fifty-two patients undergoing elective cholecystectomy, inguinal hernia repair or colonic/colorectal surgery were recruited to this pilot study. According to cardiological evaluation, non-high-risk patients who were on long-term treatment with low-dose ASA were eligible for inclusion. Patients were allocated randomly to continuous use of ASA or discontinuation of ASA intake for 5 days before until 5 days after surgery. The primary outcome was the incidence of major haemorrhagic and thromboembolic complications within 30 days after surgery.

RESULTS

A total of 26 patients were allocated to each study group. One patient (3.8%) in the ASA continuation group required re-operation due to post-operative haemorrhage. In neither study group, further bleeding complications occurred. No clinically apparent thromboembolic events were reported in the ASA continuation and the ASA discontinuation group. Furthermore, there were no significant differences between both study groups in the secondary endpoints.

CONCLUSIONS

Perioperative intake of ASA does not seem to influence the incidence of severe bleeding in non-high-risk patients undergoing elective general or abdominal surgery. Further, adequately powered trials are required to confirm the findings of this study.

The impact of the introduction of total mesorectal excision on local recurrence rate and survival in rectal cancer: long-term results

PURPOSE

To investigate the influence of the introduction of total mesorectal excision (TME) on local recurrence rate and survival in patients with rectal cancer.

METHODS

A total of 171 consecutive patients underwent anterior or abdominoperineal resection for primary rectal cancer. When the TME technique was introduced, the clinical setting, including the surgeons, remained the same. Group 1 (1993-95, n =53) underwent conventional surgery and group 2 (1995-2001, n = 118) underwent TME. All patients were followed for 7 years or until death.

RESULTS

Between the two groups, no statistically significant differences were present with regards to patient-, treatment-, or tumor-related characteristics apart from the time point of radiotherapy. The total local recurrence rates were 11 of 53 (20.8%) in group 1 and 7 of 118 (5.9%) in group 2, and the rates of isolated local recurrences were 6 of 53 (11.3%) in group 1 and 2 of 118 (1.7%) in group 2. Both differences were highly statistically significant. The disease-free survival in groups 1 and 2 was 60.4 and 65.3% at 5 years, and 58.5 and 65.3% at 7 years, respectively. Excluding patients with synchronous or metachronous distant metastasis from the analysis, both the disease-free survival and the cancer-specific survival were statistically significantly better in group 2 than in group 1. No statistically significant difference between the two groups was detected regarding the overall survival.

CONCLUSIONS

The introduction of TME led to an impressive reduction of the local recurrence rate. Survival is mainly determined by the occurrence of distant metastasis, but TME seems to improve survival in patients without systemic disease.

Leucocyte-depleted blood transfusion is an independent predictor of surgical morbidity in patients undergoing elective colon cancer surgery-a single-center analysis of 531 patients

BACKGROUND

Leukocyte-depleted packed red blood cells (PRBC) were introduced to reduce potential immunomodulatory effects and transfusion-associated morbidity. It has, however, remained unclear, if leucocyte depletion prevents negative side effects of blood transfusion. The aim of this analysis was to examine the effects of leukocyte-depleted PRBC on surgical morbidity after elective colon cancer surgery.

METHODS

Data were prospectively collected from 531 consecutive patients undergoing elective colon cancer surgery at a single high-volume center (University Hospital) from 2002 to 2008. Potentially predictive factors for surgical morbidity were tested on univariate and multivariate analysis.

RESULTS

A total of 531 patients with colon cancer were included. A curative (R0) resection was performed in 497 patients (94%). The mortality rate, overall morbidity rate, and surgical morbidity rate were 1.1, 33, and 21%, respectively. Some 135 patients (25%) received perioperative transfusion of PRBCs. On multivariate analysis age (odds ratio [OR] 1.04, 95% confidence interval [95% CI] 1.02-1.06; P = 0.001), BMI (OR 1.08, 95% CI 1.03-1.13; P = 0.003), and PRBC transfusion (2.4, 1.41-4.11; P = 0.001) were revealed as independent predictors of surgical morbidity. The risk of surgical complications increased continuously with the amount of transfused PRBCs. The adverse impact of PRBC transfusion was neither restricted to the timepoint of transfusion (intraoperative or postoperative), nor to the kind of complication (infectious vs noninfectious complication).

CONCLUSION

Perioperative transfusion of leukocyte-depleted PRBCs has a significantly negative effect on surgical morbidity of patients undergoing elective colon cancer surgery. The use of perioperative blood transfusions in these patients should be avoided, whenever possible.

Influence of Bovine Slurry Deposition on the Structure of Nodulating Rhizobium leguminosarum bv. viciae Soil Populations in a Natural Habitat

The population of nodulating R. leguminosarum bv. viciae in soil from a grass-covered valley area which had been used for bovine slurry deposition over a period of 5 years was analyzed. For these studies, a rapid and reproducible method based on enterobacterial repetitive intergenic consensus (ERIC)-PCR was applied to identify Rhizobium strains which had infected pea nodules. Soil samples were taken from different areas and further analyzed in plant tests to determine the impact of the application of slurry (polluted or nonpolluted), the slope position (summit or toe), and exposure (north or south). After comparison of all PCR fingerprint patterns, 24 strain groups were defined. Some strain groups from the nonpolluted soil were suppressed in the polluted samples, and new strain groups were detected in the slurry-polluted soil. After analyzing relationships between the strain groups, we determined the influences of local factors on the nodulating R. leguminosarum bv. viciae population. We show that one of those local parameters, slope position, had significantly greater impact on the composition of the Rhizobium population than the presence of slurry.

[Rectal cancer. How much radiotherapy do surgery patients need?]

With the introduction of total mesorectal excision in rectal cancer treatment, local recurrence rates could be reduced below 10%. Previously such results could be achieved only in combination with multimodal therapy. Therefore the role of multimodal therapy had to be redefined. Randomized controlled trials have shown that the local recurrence rate can be reduced with no effect on overall survival and that neoadjuvant radiotherapy is superior to adjuvant radiotherapy. Controversy exists however about the best way of application, as either short-course radiotherapy (5x5 Gy) or combined radiochemotherapy, but not about its necessity, especially considering recent reports about late side effects of radiotherapy. It was the aim of this paper to explore the literature for the amount of radiotherapy surgical patients for rectal cancer really need. Interestingly, those with high rectal tumors do not benefit from radiotherapy. Further randomized trials are however required to address the need of radiotherapy in UICC tumor stages II or III with negative circumferential margin.

Fluorescence decay-time constants in organic liquid scintillators

The fluorescence decay-time constants have been measured for several scintillator mixtures based on phenyl-o-xylylethane (PXE) and linear alkylbenzene (LAB) solvents. The resulting values are of relevance for the physics performance of the proposed large-volume liquid scintillator detector Low Energy Neutrino Astronomy (LENA). In particular, the impact of the measured values to the search for proton decay via p-->K(+)nu is evaluated in this work.

Assessing the suitability of Norway spruce wood as an environmental archive for sulphur

The aim of this study was to assess the suitability of Norway spruces (Picea abies L. Karst.) as an environmental archive for sulphur. For this purpose spruce trees were sampled in two distinct regions of Switzerland: the Alps and the Swiss Plateau, which differ significantly with respect to S immission. Wood samples were measured using two methods: LASER Ablation high resolution inductively coupled plasma mass spectrometry (LA-HR-ICP-MS) and inductively coupled plasma optical emission spectrometry (ICP-OES) after acid digestion. Independently corroborated by previous measurements of sulphur in peat bogs, the rise and fall of sulphur dioxide pollution in Switzerland appears to be reflected in spruce wood sulphur content. While the wood sulphur content profile of trees sampled in the Alps is relatively flat, the profiles of trees located on the Swiss Plateau display a characteristic sulphur peak. This corresponds to air pollution data in the different regions and indicates that the trees reacted on the changing S supply and recorded a pollution signal in the wood.

Synthetic TiO2 nanoparticle emission from exterior facades into the aquatic environment

We present direct evidence of the release of synthetic nanoparticles from urban applications into the aquatic environment. We investigated TiO(2) particles as these particles are used in large quantities in exterior paints as whitening pigments and are to some extent also present in the nano-size range. TiO(2) particles were traced from exterior facade paints to the discharge into surface waters. We used a centrifugation based sample preparation which recovers TiO(2) particles between roughly 20 and 300nm. Analytical electron microscopy revealed that TiO(2) particles are detached from new and aged facade paints by natural weather conditions and are then transported by facade runoff and are discharged into natural, receiving waters. Microscopic investigations are confirmed by bulk chemical analysis. By combining results from microscopic investigations with bulk chemical analysis we calculated the number densities of synthetic TiO(2) particles in the runoff.