A card-sorting tool to measure expert versus novice thinking in scientific research.

Undergraduate research and laboratory experiences provide a wide range of benefits to student learning in science and are integral to imbed authentic research experiences in biology labs. While the benefit of courses with research experience is widely accepted, it can be challenging to measure conceptual research skills in a quick and easily scalable manner. We developed a card-sorting task to differentiate between novice and expert conceptualization of research principles. There were significant differences in the way faculty/postdocs, graduate students, and undergraduate students organized their information, with faculty/postdocs more likely to use deep feature sorting patterns related to research approach. When provided scaffolding of group names reflecting expert-like organization, participant groups were better able to sort by that organization, but undergraduate students did not reach expert levels. Undergraduates with Advanced Placement experience were more likely to display expert-like thinking than undergraduates without Advanced Placement Biology experience and non-PEER (persons excluded because of their Ethnicity or Race) students displayed more expert-like thinking than PEER students. We found evidence of undergraduates in various stages of development toward expert-like thinking in written responses. This card-sorting task can provide a framework for analyzing student's conceptualizations of research and identify areas to provide added scaffolding to help shift from novice-like to expert-like thinking.

Children post liver transplantation hospitalized with fever are at a high risk for bacterial infections.

BACKGROUND: Although infections post liver transplantation are a main cause of morbidity and mortality, data are limited on transplanted children. The objective of this study was to investigate the incidence, etiology, and predictors of infection in pediatric liver transplant recipients (LTR) in the specific practical clinical setting of hospitalization for fever in order to elucidate the appropriate management of these patients. METHODS: Clinical and laboratory data were retrospectively collected for all febrile pediatric LTR hospitalized from 2004 to 2012. RESULTS: We analyzed 133 hospital admissions for fever among 44 pediatric LTR. Of these, 73 bacterial (54.8%) and 46 viral infections (34.5%) were diagnosed. No cases of protozoa or fungal infections were reported. Bacterial infections were most frequent during the first year post transplantation with ascending cholangitis being the most prevalent. Twenty-six (36%) bacterial infections were microbiologically documented and 47 (64%) were clinically documented. Of the microbiologically confirmed cases, gram-negative bacteria, namely Enterobacteriaceae, were most common (57.7%). Seven cases of bacteremia were observed including 1 case presenting with severe sepsis. Compared with the white blood cell count and absolute neutrophil count, C-reactive protein level was found to be a more sensitive biomarker for bacterial disease. Older age on admission was a significant risk factor for bacterial infection. CONCLUSION: Febrile hospitalized pediatric LTR are immunocompromised hosts at high risk for bacterial infections, and usually warrant prompt evaluation and empirical antibiotic treatment upon admission.

Papillary-cystic variant of acinic cell carcinoma of the salivary gland diagnosed by fine needle aspiration biopsy. A case report.

BACKGROUND: Fine needle aspiration (FNA) biopsy is reliably used to classify most conditions involving the salivary glands. It is useful for establishing, or at least suggesting, the diagnosis in unusual cases or narrowing the differential diagnosis. CASE: A 25-year-old male presented with a slowly enlarging mass of the left parotid. FNA biopsy of the parotid gland was performed, and a diagnosis of papillary-cystic variant of acinic cell carcinoma was suggested. The patient underwent incomplete resection of the lesion, which was interpreted as acinic cell carcinoma. CONCLUSION: Papillary-cystic variant of acinic cell carcinoma is rarely seen, especially in young people. FNA biopsy is a useful diagnostic procedure that can help diagnose this relatively uncommon type of salivary gland neoplasm and guide its management.

Bilateral synchronous breast cancer: mode of detection and comparison of histologic features between the 2 breasts.

BACKGROUND: Bilateral synchronous breast cancer is uncommon (accounting for 1.0%-2.6% of all patients with breast cancer), and most physicians do not accumulate a large personal experience of patients with this disease. We reviewed our experience with patients with bilateral synchronous breast cancer, focusing on the mode of detection and histologic features in the 2 breasts. METHODS: The charts of patients who were treated at this institution for bilateral synchronous breast cancer during the 15-year period of 1984 through 1999 were reviewed. Information regarding age, mode of detection, histopathologic features, treatment, and overall survival were analyzed. RESULTS: During the study period, 51 patients (all women) were treated at our institution for bilateral synchronous breast cancer. This comprised 2.1% of all patients (n = 2382 patients) treated for breast cancer during the same period of time. The first cancer was detected by palpation in 81% and by mammography in 14%. The corresponding figures for the contralateral cancer were 24% and 54%, respectively. The histologic type of cancer was identical in the 2 breasts in 29 patients (57%) and was different between the 2 breasts in 22 patients (43%). The overall 10-year survival rate was 63%. CONCLUSIONS: Bilateral synchronous breast cancer is often detected by mammography and is frequently of the same histologic type as the index cancer. A better awareness of the risk for this disease may help detect bilateral breast cancer earlier.

Cyclin D1, retinoblastoma, p53, and Her2/neu protein expression in preinvasive breast pathologies: correlation with vascularity.

OBJECTIVES: Preinvasive breast pathologies show a degree of vascularization that correlates with risk of invasion. Recently, numerous oncogenes and tumor suppressor genes have been shown to regulate neovascularization. Therefore, we examined archival tissues of preinvasive breast pathologies by immunohistochemistry for alterations in the expression of four proteins, cyclin D1, retinoblastoma (Rb), p53, and Her2/neu, known to be important in breast tumorgenesis, and correlated these data with tissue vascularity. METHODS: Vascularity was determined by immunologic detection of von Willebrand factor. For carcinoma in situ (CIS) both stromal vascularity (MVD) and vascular cuffing (MCD) were determined. RESULTS: We found that cyclin D1 expression was increased in usual hyperplasia (11% of cases). Atypical hyperplasia, noncomedo CIS and comedo CIS were positive in 43, 49, and 57% of cases, respectively. Changes in Rb and p53 were rare in hyperplasia but occurred in 8 and 10% of CIS, respectively. Her2/neu protein was identified rarely in atypical hyperplasia and in both noncomedo and comedo ductal CIS. Neither Rb nor Her2/neu expression correlated with vascularity. p53 immunoreactivity correlated positively with both MCD and MVD. Cyclin D1 was negatively associated with MVD. CONCLUSION: These data suggest that p53 and cyclin D1 proteins may regulate the microvessel density of preinvasive breast pathologies.

Multilobated large B-cell lymphoma diagnosed cytologically. A case report.

BACKGROUND: Fine needle aspiration (FNA) biopsy can be used to reliably classify most conditions involving lymph nodes or, at least, significantly reduce the differential diagnosis. CASE: A 70-year-old male presented with an ulcerated mass arising from the left tonsillar fossa and involving the anterior and posterior pillars. A biopsy of the tonsillar mass performed at an outside hospital was interpreted as a large cell undifferentiated carcinoma. Subsequently the patient developed systemic lymphadenopathy. A bone scan showed intense uptake within the medial tibial plateau of the left knee. FNA biopsy of the right axillary mass was interpreted at University of Cincinnati Medical College as a large cell lymphoma, multilobated type. Histologic and immunohistochemical studies of the lymph node confirmed the presence of multilobated B-cell lymphoma. Lymphoma chemotherapy was initially successful but was discontinued due to toxicity. The patient died two months after the initial cytologic diagnosis of lymphoma. CONCLUSION: Multilobated lymphomas are an unusual variant of non-Hodgkin's lymphomas (mostly B-cell type). Cytology and immunocytochemistry are useful diagnostic procedures that can help to diagnose this relatively uncommon type of lymphoma and significantly reduce the possibility of misdiagnosis.

Angiogenic growth factors in preinvasive breast disease.

Recently, we showed that preinvasive breast pathologies, such as usual hyperplasia, atypical hyperplasia, and carcinoma in situ, have an increased vascularity when compared with normal breast tissue (S. C. Heffelfinger et al., Clinical Cancer Res., 2: 1873-1878, 1996). To understand the mechanism of this increased vascularity, we examined by immunohistochemistry each of these pathological lesions for the expression of angiogenic growth factors. These studies showed that normal breast tissue contains numerous angiogenic agents, particularly vascular endothelial cell growth factor and basic fibroblast growth factor. At the transition from normal epithelium to proliferative breast disease, insulin-like growth factor (IGF) II expression was increased, primarily in the stroma and infiltrating leukocytes. However, among proliferative tissues, IGF I decreased with increasing vascularity. Finally, both epithelial vascular endothelial growth factor and epithelial and leukocytic platelet-derived endothelial cell growth factor increased at the transition to carcinoma in situ, whereas stromal and leukocytic basic fibroblast growth factor were elevated only in invasive carcinoma. Therefore, during histological progression there is also a complex progression of angiogenic growth factors. For CIS, two forms of vascularity are found: stromal microvascular density (MVD), and vascularity associated with the epithelial basement membrane (vascular score). There was 35% discordance between these two measurement systems. Among carcinoma in situ cases, decreases in stromal IGF II were associated with increasing vascular scores but not MVD, and increases in platelet-derived endothelial cell growth factor were associated with increasing MVD but not the vascular score. The presence of discordance and differential association with specific angiogenic agents suggests that these two forms of vascularity may be differentially regulated.

Signaling pathways mediating gastrin's growth-promoting effects.

In addition to its fundamental role in stimulating gastric acid secretion, the peptide hormone gastrin induces growth-promoting effects on diversity of target cells. Various mechanisms, including endocrine, paracrine, and autocrine, have been proposed for gastrin's growth-promoting actions. The mitogenic effects of gastrin are mediated by specific cell surface receptors activated after gastrin binding. The functionally defined receptors for gastrin include cholecystokinin A (CCKA) receptor, which is discriminating for sulfated CCK8; cholecystokinin B (CCKB)/gastrin receptor, which binds gastrin17 sulfated, and nonsulfated CCK8 with nearly equal affinities; cholecystokinin C (CCKC), which is a low-affinity gastrin binding protein; and novel, high-affinity receptors selective for amidated gastrin, processing intermediates of gastrin, or both. The signaling pathways mediating gastrin's stimulation of the CCKB/gastrin receptor have been progressively outlined, and the pathways mediating other receptors have been slowly emerging. Engagement of the gastrin receptor initiates various biochemical and molecular events, including recruitment and activation of tyrosine kinases, activation of the phospholipase C signaling pathway leading to phosphoinositide breakdown, intracellular calcium mobilization and protein kinase C stimulation, activation of the mitogen-activated protein kinase pathway, and induction of early response genes. Current emphasis is on understanding the functional significance of processing intermediate forms of gastrin, and the receptor subtypes and pathways that promote the trophic/mitogenic effects of the different molecular forms of gastrin.

Barrett's esophagus. Reducing the risk of progression to adenocarcinoma.

Barrett's metaplasia develops in 6% to 14% of individuals with gastroesophageal reflux. Barrett's adenocarcinomas are increasing in epidemic proportions for, as yet unknown, reasons; approximately 0.5% to 1% of patients with Barrett's metaplasia develop adenocarcinoma. Heartburn duration and frequency (but not severity), male gender, and white race are major risk factors for developing cancer. Obesity and smoking are weak risk factors. Survival is determined by depth of tumor invasion (stage). Once invasion of the muscularis propria occurs, most patients have developed widespread metastasis, even when clinical staging studies are negative. No currently available therapy results in prolonged survival once metastases develop. Thus, the more widespread use of effective surveillance strategies is the only currently available means for reducing the morbidity and mortality associated with Barrett's adenocarcinoma.

Thyroid transcription factor-1 and cytokeratins 7 and 20 in pulmonary and breast carcinoma.

OBJECTIVE: To evaluate the immunohistochemical expression of a lung epithelial gene transcription factor, thyroid transcription factor-1 (TTF-1), in lung and breast carcinoma in pulmonary cytologic preparations and to correlate the results with the expression of cytokeratin 7 (CK7) and 20 (CK20). STUDY DESIGN: Cell blocks of cytologic specimens were immunostained with antibodies to TTF-1, CK7 and CK20. Specimens included 41 primary lung carcinomas (21 adenocarcinomas, 8 squamous cell carcinomas and 12 small cell undifferentiated carcinomas) and 6 metastatic breast adenocarcinomas. RESULTS: The lung adenocarcinomas showed nuclear reactivity for TTF-1 in 76% (16/21) of the cases and a staining combination of CK7+/CK20- in 95% (20/21) of the cases. Only one case was CK7+/CK20+. All the breast carcinomas were nonreactive to TTF-1, and all were CK7+/CK20-. The squamous cell carcinomas and small cell undifferentiated carcinomas showed TTF-1 positivity in 38% (3/8) and 83% (10/12), respectively.

Gastrin induces IP3 formation through phospholipase C gamma 1 and pp60c-src kinase.

We have previously reported that gastrin induces a rapid and transient tyrosine phosphorylation of phospholipase C gamma 1 (PLC gamma 1) in association with inositol 1,4,5-trisphosphate (IP3) formation in rat colonic epithelial cells (34). In this study, we demonstrate that gastrin regulates IP3 formation mainly through PLC gamma 1 isozyme. Immunoblotting analysis revealed the expression of PLC beta 3 and -gamma 1, but not PLC beta 1, -beta 2, or -beta 4 in the rat colonic epitheliums. To explore what PLC isozyme(s) modulates gastrin effect on IP3, immunoneutralizing antibody to PLC beta 1, -beta 3, or -gamma 1 was introduced into the colonic cells using a lipid carrier. The gastrin-stimulated increase in IP3 concentration was specifically prevented by anti-PLC gamma 1 but not by anti-PLC beta 1 or -beta 3 antibody. Immunoprecipitation assays have also revealed that gastrin promoted an increase in tyrosine phosphorylation and co-precipitation of a 60 kDa src kinase with PLC gamma 1. Administration of antibody specific to pp60c-src into the colonic cells prevented the gastrin-stimulated increases in IP3. Tyrosine phosphorylation of PLC gamma 1 may be a major mechanism through which gastrin regulates IP3 level in the colonic cells. Pretreatment of cells with the tyrosine kinase inhibitor genistein abrogated gastrin's effect on IP3, while extended pretreatment with pertussis toxin, a G-protein inhibitor, did not affect the ability of gastrin to stimulate IP3 formation. Colonic cells expressed the G alpha i subunits1-3; however, immunoblotting analysis did not reveal any difference in G alpha i proteins' expression between control and gastrin treated cells. The results provide direct evidence that gastrin regulates IP3 level by a signaling mechanism that involves PLC gamma 1 and pp60c-src kinase.

Prevalence of Salmonella in broilers at retail outlets, processing plants and farms in Malaysia.

A study was conducted to estimate the prevalence of Salmonella among broilers retailed at wet-markets and processing plants. Litter and feed samples obtained from both broiler and breeder farms were also examined for Salmonella. A total of 158 out of 445 (35.5%) and 52 out of 104 (50.0%) broiler carcasses obtained from wet-markets and processing plants were contaminated with Salmonella, respectively. Salmonella was isolated from 14 out of 98 (14.3%) samples of intestinal content. Litter samples from broiler and breeder farms were positive for Salmonella, 8/40 (20%) and 2/10 (20%), respectively. Salmonella isolates (230) belonging to 15 different serovars were isolated. Predominant serovars were S. enteritidis, S. muenchen, S. kentucky and S. blockley.

Vascularity of proliferative breast disease and carcinoma in situ correlates with histological features.

The level of vascularity within an invasive breast carcinoma is a predictor of metastatic potential and survival. However, little is known about the vascular potential and prognostic value of angiogenesis in preinvasive breast pathology. Women with proliferative breast disease or carcinoma in situ are at increased risk of developing invasive breast cancer. This relative risk increases in correlation with defined histopathological features. We asked whether these early proliferative lesions and carcinoma in situ were capable of inducing a vascular supply. Vascularity in preinvasive archival paraffin-embedded breast tissue from 90 patients was quantified by immunohistochemical identification of vessels using anti-von Willebrand factor. Vascular scores were analyzed with respect to histopathological diagnosis, age at diagnosis, and presence of coincident invasive disease. These data indicate that: (a) the vascularity of histopathologically normal epithelium is greater in breasts containing invasive disease than in breasts lacking invasive disease; (b) simple proliferative breast disease induces a vascular supply greater than that of normal breast epithelium; and (c) vascularity increases in proportion to epithelial lesion progression and relative risk of invasion. These studies indicate that the vascularity of preinvasive breast pathology may be a clinically useful predictor of invasive breast cancer.

Hematologic malignancies developing in Syrian golden hamsters during induction of pancreatic carcinoma.

We report 30 hematologic malignancies arising in 25 of 236 Syrian golden hamsters (SGH) that received combinations of N-nitrobis(2-oxopropyl)amine (BOP) and Streptozotocin (STZ). Lesions developed with morphological similarity to human small lymphocytic (n = 7), diffuse mixed (n = 2), diffuse large cell lymphoma (n = 13), follicular lymphoma (n = 2), anaplastic large cell lymphoma (n = 3), hairy cell leukemia (n = 2), malignant histiocytosis (n = 1) and discordant lymphomas (n = 5). The types and distribution of these lesions are different from epizootic lymphomas in SGH. We also report a higher percentage (12 versus 4.6%) and the earlier appearance (< or = 40 versus 80-112 weeks) compared with aging-associated spontaneous SGH lymphoma. The features of these hematologic malignancies have not been previously reported in epizootic or aging-associated spontaneous lymphomas and therefore suggest a new class of hematologic lesions in SGH. Benign and atypical hyperplasia correlated with STZ administration (r = 0.97, P = 0.03). The malignant lesions correlated with areas of lymphoid hyperplasia (r = 0.78, P= 0.004). Only one of the 21 untreated SGH spontaneously developed a low grade lymphoma. The unusual types, distribution and occurrence of these lesions may suggest a role for these carcinogens in their induction.

Molecular analysis of isolates of Salmonella typhi obtained from patients with fatal and nonfatal typhoid fever.

Molecular characterization of a total of 52 human isolates of Salmonella typhi from Papua New Guinea was performed by using pulsed-field gel electrophoresis (PFGE) after digestion of chromosomal DNA with three restriction endonucleases, XbaI (5'-TCTAGA-3'), AvrII (5'-CCTAGG-3'), and SpeI (5'-ACTAGT-3'). Of the 52 isolates tested, 11 were obtained from patients with fatal typhoid fever and 41 were obtained from patients with nonfatal disease. The 52 isolates showed limited genetic diversity as evidenced by only three different PFGE patterns detected following digestion with XbaI (patterns X1 to X3; F [coefficient of similarity] = 0.86 to 1.0), four patterns detected following digestion with AvrII (patterns A1 to A4; F =0.78 to 1.0), and two patterns detected following digestion with SpeI (patterns S1 and S2; F = 0.97 to 1.0). Of the 52 isolates, 37 were phage typed, and all belonged to phage type D2. All 11 isolates obtained from patients with fatal typhoid fever were identical (F = 1.0) and possessed the PFGE pattern combination X1S1A1, whereas the 41 isolates from patients with nonfatal typhoid fever had various PFGE pattern combinations, the most common being X2S1A2 (39%), X1S1A1 (24%), and X1S1A2 (15%). Thus, all the isolates from patients with the fatal disease had the X1 and A1 patterns, whereas the majority of the isolates from patients with nonfatal typhoid fever possessed the X2 and A2 patterns. The data suggest that there is an association among strains of S. typhi between genotype, as assessed by PFGE patterns, and the capability to cause fatal illness. Analysis of blood and fecal isolates of S. typhi from the same patient also indicated that some genetic changes occur in vivo during the course of infection.

Molecular analysis of environmental and human isolates of Salmonella typhi.

Molecular characterization of a total of 54 isolates of Salmonella typhi from Santiago, Chile, was performed by pulsed-field gel electrophoresis (PFGE) after digestion of chromosomal DNA with three restriction endonucleases: XbaI (5'-TCTAGA-3'), AvrII (5'-CCTAGG-3'), and SpeI (5'-ACTAGT-3'). Thirteen of the 54 isolates were obtained from environmental sources (sewage and river water), and the rest were isolates from clinical cases of typhoid fever. Considerable genetic diversity was detected among the human isolates obtained in 1994, as evidenced by the presence of 14 to 19 different PFGE patterns among 20 human isolates, with F (coefficient of similarity) values ranging from 0.69 to 1.0 (XbaI), 0.61 to 1.0 (AvrII), and 0.70 to 1.0 (SpeI). A total of eight phage types were detected among these 20 isolates, with 50% possessing the E1 or 46 phage type. There was no correlation between PFGE pattern and phage types. Similar diversity was seen among 21 isolates obtained in 1983, with 17 to 19 PFGE patterns detected and F values of 0.56 to 1.0 (XbaI), 0.55 to 1.0 (AvrII), and 0.67 to 1.0 (SpeI). Comparison of these two groups of human isolates obtained 11 years apart indicated that certain molecular types of S. typhi are shared and are able to persist for considerable periods. A similar degree of genetic diversity was also detected among the environmental isolates of S. typhi, for which 10 to 12 different PFGE patterns were detected among the 13 isolates analyzed, with F values ranging from 0.56 to 1.0 (XbaI), 0.52 to 1.0 (AvrII), and 0.69 to 1.0 (SpeI). Certain molecular types present among the environmental isolates of S. typhi were also found among the human isolates from the same time period, providing evidence for the epidemiological link between environmental reservoirs and human infection.

Early signalling mechanism in colonic epithelial cell response to gastrin.

The hormone gastrin exerts a growth-promoting effect on gastrointestinal cells. The molecular mechanisms by which colonic epithelial cells respond to gastrin are still poorly understood. In this study, we demonstrate a novel feature of the action of gastrin on normal colonic cells, namely the rapid phosphorylation on tyrosine of phospholipase C gamma 1 (PLC gamma 1). Tyrosine phosphorylation of PLC gamma 1, elicited by gastrin, was transient, concentration-dependent, and was abrogated by pretreating the colonic cells with the gastrin-receptor antagonist proglumide, the tyrosine kinase inhibitor genistein, and by removal of the tyrosine phosphatase inhibitor orthovanadate from the isolation buffer. Tyrosine phosphorylation of PLC gamma 1 correlated with the time- and concentration-dependent decrease in the mass of membrane phosphatidylinositol 4,5-bisphosphate (PIP2) and the increase in the epithelial concentration of inositol 1,4,5-trisphosphate (IP3). Likewise, the stimulated increase in IP3 was also prevented by proglumide and genistein. Gastrin induced a definite but transient increase in the intracellular concentration of free Ca2+ [Ca2+]i, and increased membrane-translocation of immunoreactive alpha- and beta-protein kinase C. The data thus indicate that gastrin elicits at least one signalling cascade, through rapid tyrosine phosphorylation of PLC gamma 1, leading to the activation of a PIP2-specific PLC pathway.

Analysis of Salmonella typhi isolates from Southeast Asia by pulsed-field gel electrophoresis.

Pulsed-field gel electrophoresis (PFGE) revealed that multiple genetic variants of Salmonella typhi are simultaneously present in Southeast Asia and are associated with sporadic cases of typhoid fever and occasional outbreaks. Comparative analysis of PFGE patterns also suggested that considerable genetic diversity exists among S. typhi strains and that some PFGE patterns are shared between isolates obtained from Malaysia, Indonesia, and Thailand, implying movement of these strains within these regions of Southeast Asia, where they are endemic.

Intranuclear binding of nucleoplasmin.

Many proteins--including not only structural proteins, but also enzymes, hormone receptors, and other transcription factors--accumulate to much higher nuclear than cytoplasmic concentrations. Nuclear localization sequences or signals (NLSs) within their primary structures entrain specific transport of these proteins through the nuclear pore complexes. This transport process is energy-dependent, but evidence for a true active transport mechanism is not conclusive. An alternative mechanism--facilitated transport of NLS proteins followed by their intranuclear binding--has been implicated by experiments with oil-isolated nuclei. However, there has been no agreement as to a role for binding in the in vivo nuclear accumulation of NLS-containing proteins. We demonstrate herein that a prototypical NLS protein, nucleoplasmin (Np), binds within the nucleus of the living Xenopus oocyte and that this binding accounts for its nuclear accumulation.