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Focused ion beam microscopy and scanning electron microscopy have been used to characterise the porosity of the oxide scale of an experimental 9Cr–1Mo steel sample exposed for 4580 h in a CO2-rich environment. The magnetite shows a high frequency of spherical pores (~ 1 µm3) with no interconnectivity. The Cr-rich spinel layer shows greater interconnectivity, but no single pore spans the total oxide scale. A mechanism for the formation of the different morphologies observed across the scale is proposed, linking porosity changes across the oxide scale to the carburisation and elemental segregation of Cr within the substrate. [ABSTRACT FROM AUTHOR]

CD44 is a multifunctional protein involved in cell adhesion and signaling. The role of CD44 in prostate cancer (PCa) development and progression is controversial with studies showing both tumor-promoting and tumor-inhibiting effects. Most of these studies have used bulk-cultured PCa cells or PCa tissues to carry out correlative or overexpression experiments. The key experiment using prospectively purified cells has not been carried out. Here we use FACS to obtain homogeneous CD44+ and CD44− tumor cell populations from multiple PCa cell cultures as well as four xenograft tumors to compare their in vitro and in vivo tumor-associated properties. Our results reveal that the CD44+ PCa cells are more proliferative, clonogenic, tumorigenic, and metastatic than the isogenic CD44− PCa cells. Subsequent molecular studies demonstrate that the CD44+ PCa cells possess certain intrinsic properties of progenitor cells. First, BrdU pulse-chase experiments reveal that CD44+ cells colocalize with a population of intermediate label-retaining cells. Second, CD44+ PCa cells express higher mRNA levels of several ‘stemness’ genes including Oct-3/4, Bmi, β-catenin, and SMO. Third, CD44+ PCa cells can generate CD44− cells in vitro and in vivo. Fourth, CD44+ PCa cells, which are AR−, can differentiate into AR+ tumor cells. Finally, a very small percentage of CD44+ PCa cells appear to undergo asymmetric cell division in clonal analyses. Altogether, our results suggest that the CD44+ PCa cell population is enriched in tumorigenic and metastatic progenitor cells.Oncogene (2006) 25, 1696–1708. doi:10.1038/sj.onc.1209327; published online 30 January 2006 [ABSTRACT FROM AUTHOR]

The SENCAR stock of mice has proved to be a useful model in dissecting out the multistage nature as well as the critical mechanisms involved in skin tumorigenesis. This outbred stock was selectively bred to be susceptible to initiation with 7,12-dimethylbenz[a]anthracene (DMBA) and promotion with 12-O-tetradecanoylphorbol-13-acetate (TPA). In order to obtain mice more suitable for genetic analyses of tumor susceptibility and tissue transplantation studies, several inbred lines of mice were derived from the SENCAR stock. One of these lines, the SSIN mice, has a higher susceptibility to tumor promotion compared to the SENCAR stock but is very resistant to tumor progression. On the other hand, the SENCAR B/Pt mice, derived also from the outbred stock, not only have a tumor promotion susceptibility almost identical to the SSIN mice, but they also have a high susceptibility to tumor progression. In order to understand the nature of the phenotypic differences between these two inbred lines we have characterized them using several parameters and markers that are associated with the progression of papillomas to squamous cell carcinoma (SCC). In this sense we analysed the tumor multiplicity and SCC incidence, and the expression of markers of progression and cell cycle related proteins in papillomas derived from both strains. Our results showed that while both strains have a similar papilloma multiplicity and incidence the SENCAR B/Pt mice have 67% incidence of SCC, compared to 0% in the SSIN. SENCAR B/Pt papillomas at 30 weeks of promotion have a higher and aberrant expression of K13, and loss of connexin 26. TGF-β1 was found to be over-expressed in the suprabasal and superficial cells in the SENCAR B/Pt papillomas, while it was only expressed in the superficial cell layer in those derived from SSIN. The SENCAR B/Pt papillomas also showed an enlarged proliferative compartment with overexpression of cyclin D1 and PCNA as seen by immunohistochemistry and Western blot. [ABSTRACT FROM PUBLISHER]

Administrative databases hold the potential to have a significant impact on the development of effective child welfare programs and policies. This article discusses the strengths and weaknesses of administrative databases, issues with their implementation and data analysis, and effective presentation of their data at different levels in child welfare organizations. [ABSTRACT FROM AUTHOR]

Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is useful to obtain specimens from lesions underlying deep parts of the liver and spleen. However, the development of novel ancillary techniques must be explored to reduce the number of needle passes and potential adverse effects during this procedure. We conducted an animal study using a swine to demonstrate technical feasibility of in vivo cytological observation of liver and spleen using the high-resolution microendoscopy (HRME) system under EUS guidance. We successfully performed the study. No significant acute adverse events occurred during the procedure. The HRME system could obtain clear images representing cytology-level morphology of spleen and liver. Hence, it is found out that in vivo cytological observation of liver and spleen using the HRME system under EUS guidance is technically feasible.

Introduction: Supine tachycardia, frequently encountered in diabetic patients, is usually considered as an isolated diabetic complication in cardiac autonomic neuropathy. The objective of this study was to determine independent predictor factors of supine tachycardia among the clinical characteristics of type 2 diabetes mellitus., Methods: This prospective study included type 2 diabetic patients. Supine tachycardia was considered as 10 minutes resting heart rate equal or higher than 80 beats/minutes. According to presence or not of supine tachycardia, two groups were identified: tachycardia diabetic patients and none tachycardia diabetic patients. Cardiovascular autonomic tests: deep breathing, hand-grip, and mental stress tests and blood tests were performed in all patients. Statistical analysis was done using the Student's t-test, and univariate and multivariate logistic regression analysis., Results: We included 91 patients. The vagal response measured by the deep breathing test was 24.5 ± 5.7% in tachycardia diabetic patients vs 35.6 ± 6.8% in none tachycardia diabetic patients (P=0.007). The odds of supine tachycardia increased with serum creatinine (OR=1.350, 95% CI: 1.065-1.712, P=0.013) and serum uric acid levels (OR=1.034, 95% CI: 1.005-1.064, P=0.02) respectively, in diabetic patients. The prevalence of moderate renal failure was 45.5% in tachycardia diabetic patients vs. 21.6% in none tachycardia diabetic patients (P=0.034)., Conclusion: A high frequency of supine tachycardia in type 2 diabetic patients was significantly related with an impairment of the parasympathetic nervous system but other independent predictor factors were associated to the occurrence of this supine tachycardia, such as higher levels of serum creatinine and uric acid and moderate renal failure., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Background: Primary Hypertension (HT) is the most prevalent cardiovascular disorder worldwide and is accompanied by significant morbidity and mortality., Objectives: The present study aimed to investigate the kinetics of orthostatic Blood Pressure (BP) in primary hypertensive patients during the change from supine position to standing position as well as during the standing position using the Orthostatic Test (OT)., Patients and Methods: This prospective study included a group of 107 primary hypertensive patients (mean age: 55.82 ± 11.35 years, ranging from 39 to 80 years). Orthostatic systolic BP (Ortho SBP) was recorded for 10 minutes at the rhythm of 3 measurements per minute and was compared to the values of supine systolic preorthostatic (Preortho SBP). According to the changes in Ortho SBP, three subgroups of primary hypertensive patients were selected as follows: Subgroup A: Ortho SBP was higher than mean Preortho SBP by 10 mmHg or more. Subgroup B: Ortho SBP was lower than mean Preortho SBP by 20 mmHg or more. Subgroup C: -20 mmHg < (Ortho SBP - Preortho SBP) < + 10 mmHg. The kinetics of each group was then recorded., Results: In this study, the prevalence of subgroups A, B, and C was 27.1%, 15.9%, and 57.0%, respectively. In subgroup A, the adrenergic peripheral sympathetic alpha response was 20% during the OT., Conclusions: Hypertensives with very similar supine SBP behavior could exhibit widely different Ortho SBP. Thus, careful and effective treatment of hypertensives requires careful consideration and assessment of orthostatic BP.

Antimetabolite chemotherapy remains an essential cancer treatment modality, but often produces only marginal benefit due to the lack of tumor specificity, the development of drug resistance, and the refractoriness of slowly proliferating cells in solid tumors. Here, we report a novel strategy to circumvent the proliferation-dependence of traditional antimetabolite-based therapies. Triplex-forming oligonucleotides (TFOs) were used to target site-specific DNA damage to the human c-MYC oncogene, thereby inducing replication-independent, unscheduled DNA repair synthesis (UDS) preferentially in the TFO-targeted region. The TFO-directed UDS facilitated incorporation of the antimetabolite, gemcitabine (GEM), into the damaged oncogene, thereby potentiating the anti-tumor activity of GEM. Mice bearing COLO 320DM human colon cancer xenografts (containing amplified c-MYC) were treated with a TFO targeted to c-MYC in combination with GEM. Tumor growth inhibition produced by the combination was significantly greater than with either TFO or GEM alone. Specific TFO binding to the genomic c-MYC gene was demonstrated, and TFO-induced DNA damage was confirmed by NBS1 accumulation, supporting a mechanism of enhanced efficacy of GEM via TFO-targeted DNA damage-induced UDS. Thus, coupling antimetabolite chemotherapeutics with a strategy that facilitates selective targeting of cells containing amplification of cancer-relevant genes can improve their activity against solid tumors, while possibly minimizing host toxicity., (© 2013 Wiley Periodicals, Inc.)

Sympathetic hyperactivity may be involved in primary hypertension. The purpose of this study was to evaluate both sympathetic and vagal activity responses in patients receiving amlodipine as antihypertensive agent. Patients and Methods. This prospective study included a group of primary hypertensive patients (N = 32, mean age 54.6 ± 7.6 years). The cardiovascular autonomic tests performed in this group, before and after 3 months of daily oral administration of amlodipine, included deep breathing, hand-grip, and mental stress tests. Statistical analysis was done using the Student's t-test. Results. Cardiovascular autonomic reflexes responses before and after 3 months of amlodipine oral administration were as follows: the mental stress test stimulation method produced a central alpha adrenergic response of 23.9 ± 8.7% versus 11.2 ± 2.0% (P < 0.05), a central beta sympathetic response of 16.7 ± 9.2% versus 10.4 ± 1.3% (P < 0.05), a blood pressure increase in response to hand grip test of 20.5 ± 7.3% versus 10.7 ± 2.4% (P < 0.05), vagal response to deep breathing test was 21.2 ± 6.5% versus 30.8 ± 2.9%, (P < 0.05). Conclusion. The results attest that amlodipine may have an anti-sympathetic effect.

An effective cancer control strategy requires improved early detection methods, patient-specific drug selection, and the ability to assess response to targeted therapeutics. Recently, plasmon resonance coupling between closely spaced metal nanoparticles has been used to develop ultrasensitive bioanalytical assays in vitro. We demonstrate the first in vivo application of plasmon coupling for molecular imaging of carcinogenesis. We describe molecular-specific gold bioconjugates to image epidermal growth factor receptor (EGFR); these conjugates can be delivered topically and imaged noninvasively in real time. We show that labeling with gold bioconjugates gives information on the overexpression and nanoscale spatial relationship of EGF receptors in cell membranes, both of which are altered in neoplasia. EGFR-mediated aggregation of gold nanoparticles in neoplastic cells results in more than a 100-nm color shift and a contrast ratio of more than tenfold in images of normal and precancerous epithelium in vivo, dramatically increasing contrast beyond values reported previously for antibody-targeted fluorescent dyes.

Medullary thymic epithelial cells (mTECs) play an essential role in establishing central tolerance due to their unique capacity to present a diverse array of tissue restricted Ags that induce clonal deletion of self-reactive thymocytes. One mTEC subset expresses keratin 5 (K5) and K14, but fails to bind Ulex europaeus agglutinin-1 (UEA-1) lectin. A distinct mTEC subset binds UEA-1 and expresses K8, but not K5 or K14. Development of both mTEC subsets requires activation of the noncanonical NF-kappaB pathway. In this study, we show that mTEC development is severely impaired and autoimmune manifestations occur in mice that are deficient in IkappaB kinase (IKK)alpha, a required intermediate in the noncanonical NF-kappaB signaling pathway. Introduction of an IKKalpha transgene driven by a K5 promoter restores the K5(+)K14(+) mTEC subset in IKKalpha(-/-) mice. Unexpectedly, the K5-IKKalpha transgene also rescues the UEA-1 binding mTEC subset even though K5 expression is not detectable in these cells. In addition, expression of the K5-IKKalpha transgene ameliorates autoimmune symptoms in IKKalpha(-/-) mice. These data suggest that 1) medulla formation and central tolerance depend on activating the alternative NF-kappaB signaling pathway selectively in K5-expressing mTECs and 2) the K5-expressing subset either contains immediate precursors of UEA-1 binding cells or indirectly induces their development.

In this study we use a multi-spectral digital microscope (MDM) to measure multi-spectral auto-fluorescence and reflectance images of the hamster cheek pouch model of DMBA (dimethylbenz[alpha]anthracene)- induced oral carcinogenesis. The multi-spectral images are analyzed both in the RGB (red, green, blue) color space as well as in the YCbCr (luminance, chromatic minus blue, chromatic minus red) color space. Mean image intensity, standard deviation, skewness, and kurtosis are selected as features to design a classification algorithm to discriminate normal mucosa from neoplastic tissue. The best diagnostic performance is achieved using features extracted from the YCbCr space, indicating the importance of chromatic information for classification. A sensitivity of 96% and a specificity of 84% were achieved in separating normal from abnormal cheek pouch lesions. The results of this study suggest that a simple and inexpensive MDM has the potential to provide a cost-effective and accurate alternative to standard white light endoscopy.

Molecular characterization of cancer could have important clinical benefits such as earlier cancer detection based on molecular characterization, the ability to predict the risk of cancer progression, real time margin detection, the ability to rationally select molecular therapy and to monitor response to the therapy. We present a new class of molecular specific contrast agents for optical imaging of carcinogenesis in vivo - gold nanoparticles conjugated with monoclonal antibodies specific for cancer biomarkers.

The healthy left ventricle, with remarkable mechanical efficiency, has a gothic architecture, which results from the disposition of the myocardial fibers supported and maintained by a normal collagen matrix scaffold. This conclusion, arising from the analysis of roman and gothic buildings and from comparative biology of the left ventricles of different species, has been substantiated by the study of three-dimensional images obtained by MRI and analyzed with mathematic methods for measurements of the curvature and thickness of the ventricular walls. The assessment of left ventricular functional reserve based on the architecture has been very important in making therapeutic and surgical decisions in our patients and has important implications for the design of surgical strategies designed to try to improve ventricular function by restoring an architecture that allows more efficient ventricular mechanics. The structural approach and its combination with important advances in the knowledge of membrane channels, signaling pathways, cytokines, growth factors, neuroregulation, and targeted pharmacology, and with the advances in methods for reducing hemodynamic load and its cellular and structural consequences, is certain to bring about a dramatic change in the very serious and highly prevalent congestive failure associated with the Romanesque transformation of the diseased left ventricle., (Copyright 2001 by W.B. Saunders Company)

Background and Objective: The hamster cheek pouch carcinogenesis model, using chronic treatments of dimethylbenz[alpha]anthracene (DMBA) was used as a model system to investigate changes in epithelial tissue autofluorescence throughout the dysplasia-carcinoma sequence., Study Design/materials and Methods: Fluorescence emission spectra were measured weekly from 42 DMBA-treated animals and 20 control animals at 337, 380, and 460 nm excitation. A subset of data in which histopathology was available was used to develop diagnostic algorithms to separate neoplastic and non-neoplastic tissue. The change in fluorescence intensity over time was examined in all samples at excitation-emission wavelength pairs identified as diagnostically useful., Results: Algorithms based on autofluorescence can separate neoplastic and non-neoplastic tissue with 95% sensitivity and 93% specificity. Greatest contributions to diagnostic algorithms are obtained at 380 nm excitation, and 430, 470, and 600 nm emission. Changes in fluorescence intensity are apparent as early as 3 weeks after initial treatment with DMBA, whereas morphologic changes associated with dysplasia occur on average at 7.5-12.5 weeks after initial treatment., Conclusions: Fluorescence spectroscopy provides a potential tool to identify biochemical changes associated with dysplasia and hyperplasia, which precede morphologic changes observed in histologically stained sections., (Copyright 2001 Wiley-Liss, Inc.)

Using the hamster cheek pouch carcinogenesis model, we explore which fluorescence excitation wavelengths are useful for the detection of neoplasia. 42 hamsters were treated with DMBA to induce carcinogenesis, and 20 control animals were treated only with mineral oil. Fluorescence excitation emission matrices were measured from the cheek pouches of the hamsters weekly. Results showed increased fluorescence near 350-370 nm and 410 nm excitation and decreased fluorescence near 450-470 nm excitation with neoplasia. The optimal diagnostic excitation wavelengths identified using this model - 350-370 nm excitation and 400-450 nm excitation - are similar to those identified for detection of human oral cavity neoplasia.

The two-stage model, initiation with 7,12-dimethylbenz[a]anthracene and promotion with 12-O-tetradecanoylphorbol-13-acetate, of mouse skin carcinogenesis has been the protocol of choice to study the genetic susceptibility to carcinogens, the outbred SENCAR mouse being the most widely used skin tumor-sensitive animal model. Squamous cell carcinomas (SCCs) develop from many of the papillomas, making these mice a useful model for epithelial tumorigenesis and for the progression to malignant tumors. Nine different inbred strains derived from outbred SENCAR mice have been recently reported. Interestingly, these strains display different sensitivities to two-stage carcinogenesis, and, in particular, some of them show a dissociation between susceptibility to papilloma development and the malignant conversion of these into SCC. However, the utility of these SENCAR strains for genetic mapping is limited by the lack of information regarding DNA variant alleles among them. Therefore, we analyzed the nine inbred strains with microsatellite markers distributed along the 20 chromosomes and in this article report the variant alleles found. The information presented is likely to be helpful for linkage analysis and marker-assisted development of congenic strains between SENCAR-derived inbred strains., (Copyright 2000 Wiley-Liss, Inc.)

We previously reported that precursors within the keratin (K) 8+5+ thymic epithelial cell (TEC) subset generate the major cortical K8+5- TEC population in a process dependent on T lineage commitment. This report demonstrates that expression of a cyclin D1 transgene in K8+5+ TECs expands this subset and promotes TEC and thymocyte development. Cyclin D1 transgene expression is not sufficient to induce TEC differentiation in the absence of T lineage-committed thymocytes because TECs from both hCD3epsilon transgenic and hCD3epsilon/cyclin D1 double transgenic mice remain blocked at the K8+5+ maturation stage. However, enforced cyclin D1 expression does expand the developmental window during which K8+5+ cells can differentiate in response to normal hemopoietic precursors. Thus, enhancement of thymic function may be achieved by manipulating the growth and/or survival of TEC precursors within the K8+5+ subset.

Deregulated expression of cyclin D1 has been found in several types of human tumors. In order to investigate factors involved in human prostate cancer progression, we studied the effects of cyclin D1 overexpression on human prostate cancer cell proliferation and tumorigenicity by transfecting LNCaP cells with a retroviral vector containing human cyclin D1 cDNA. When compared to the parental and control-vector transfected LNCaP cells, these cyclin D1-transfected cells had more cells in S-phase and lower growth factor requirements. Furthermore, these cells grew more in androgen-free medium. We also detected higher levels of Rb phosphorylation and E2F-1 protein levels in LNCaP/cyclin D1 cells than that in the parental and vector control cells in medium with or without androgen. Cyclin D1 transfected clones formed tumors more rapidly than control and parental cells. These tumors were refractory to the androgen-ablation treatment by castration, whereas tumors from parental and vector-control LNCaP cells regressed within 4 weeks after castration. These results suggest that overexpression of cyclin D1 changes the growth properties, increases tumorigenicity and decreases the requirement for androgen stimulation in LNCaP cells both in vitro and in vivo.

To directly compare the expression patterns of different proteins known to be altered during mouse skin carcinogenesis, serial sections of normal and hyperplastic skin and tumors from various stages of 7,12-dimethylbenz[a]anthracene-initiated, 12-O-tetradecanoylphorbol-13-acetate-promoted female SENCAR mice were examined by immunohistochemistry. In untreated, normal mouse skin, keratin 1 (K1) and transforming growth factor-beta1 (TGFbeta1) were strongly expressed in the suprabasal layers, whereas integrin alpha6beta4 was expressed only in basal cells and only moderate staining for transforming growth factor-alpha (TGFalpha) was seen. In hyperplastic skin, TGFalpha expression became stronger, whereas expression of another epidermal growth factor (EGF) receptor ligand, heparin-binding EGF-like growth factor (HB-EGF), was strongly induced in all epidermal layers from no expression in normal skin. Likewise, the gap-junctional protein connexin 26 (Cx26) became highly expressed in the differentiated granular layers of hyperplastic skin relative to undetectable expression in normal skin. Expression of cyclin D1 in the proliferative cell compartment was seen in all benign and malignant tumors but not in hyperplastic skin. Beginning with very early papillomas (after 10 wk of promotion), expression of alpha6beta4 in suprabasal cells and small, focal staining for keratin 13 (K13) were seen in some tumors. Later (after 20-30 wk), focal areas of gamma-glutamyl transpeptidase (GGT) activity appeared in a few papillomas, whereas TGFbeta1 expression began to decrease. Cx26 and TGFalpha staining became patchier in some late-stage papillomas (30-40 wk), whereas suprabasal alpha6beta4, K13, and GGT expression progressively increased and K1 expression decreased. Finally, in squamous cell carcinomas (SCCs), there was an almost complete loss of K1 and a further decline in TGFalpha, HB-EGF, TGFbeta1, and Cx26 expression. On the other hand, almost all SCCs showed suprabasal staining for alpha6beta4 and widespread cyclin D1 and K13 expression, whereas only about half showed positive focal staining for GGT activity.

Myocardial infarction (MI) is characterized by cellular necrosis which undergoes fibrotic transformation over time. Cine magnetic resonance imaging (MRI) offers high-resolution 3-dimensional images of the left ventricular myocardium, allowing sampling of the myocardial wall thickness over the entire left ventricle. Tomographic (single-photon emission computed tomography [SPECT]) thallium images also provide 3-dimensional information on the location and level of thallium uptake, which has been shown to correlate with myocardial viability. The purposes of this study were: (1) to examine the relation between both end-diastolic and end-systolic wall thickness and normalized thallium-201 uptake over the left ventricle in a group of patients with MI, (2) to examine the relation between regional wall thickening and normalized thallium uptake, and (3) to examine the relation between thallium uptake and wall thickness both early and late after infarction. Twenty-four patients with MI underwent stress, redistribution, and reinjection thallium SPECT imaging and cine MRI within several days. Seventeen patients underwent imaging late after infarction and 7 underwent imaging early after infarction. Normalized thallium activity was correlated with MRI wall thicknesses at both end-diastole and end-systole for 18 segments for each ventricle. In addition, end-diastolic and end-systolic wall thicknesses were grouped by their corresponding thallium activity levels into percentiles. End-systolic wall thickness correlated significantly with normalized thallium uptake in 14 of 18 segments, end-diastolic wall thickness in only 4 of 18 segments, and wall thickening in only 3 of 18 segments. Mean values for end-diastolic and end-systolic wall thicknesses corresponding to severely reduced (<50%) normalized thallium activity were 9.9 +/- 1.1 and 8.5 +/- 0.6, respectively. Using receiver-operating curve analysis, end-systolic wall performed as a better diagnostic parameter than end-diastolic wall for identifying severely reduced thallium activity levels. For all levels of thallium activity, end-diastolic wall thicknesses were all thinner late versus early after MI, whereas end-systolic wall thickness was thinner only in the segments corresponding to severely reduced thallium activity. Based on these results, end-systolic wall thickness is the best noninvasive anatomic parameter of myocardial scar.

By serving as host recipients of xenografts from both humans and animals, severe combined immunodeficient (SCID) mice have become valuable to many laboratories interested in examining the pathophysiology of different diseases. To gain insight into the usefulness of the SCID mutation in retrovirus research, rhesus monkey fetal hematolymphoid tissues (liver and thymus) were used to construct a SCID-rhesus chimeric mouse (SCID-rh) and were engrafted in the renal capsule. The size and maturation of the thymic engrafts were monitored grossly, histologically, and immunologically. SCID mice were tolerant to rhesus tissues, and thymic engrafts contained thymocytes at different stages of maturation and differentiation that had morphologic features similar to age-matched rhesus thymus. Mature single positive CD2+, CD4+, and CD8+ T lymphocytes that were phenotypically similar to rhesus T lymphocytes were present at low levels (2% to 5%) in the peripheral blood and at moderately higher levels (7% to 15%) in the spleens of SCID-rh mice obtained between 12 and 15 weeks after thymus/liver engraftment. Within 3 weeks after engraftment, > 85% of the thymocytes in the thymic engrafts were immature double positive CD4+CD8+ T cells. The highest number of positive cells were seen in thymic engrafts obtained at 12 to 18 weeks. During these weeks, > 90% of the cells were double positive (CD2+CD4+, CD2+CD8+, and CD4+CD8+). After infection of the engrafted thymus tissue with simian immonodeficiency virus (SIVmac239), PCR analysis revealed successful viral infection of engrafts at 2 and 4 weeks after infection. No significant histopathologic and flow cytometric changes were observed in the thymic engrafts at 2 and 4 weeks after infection. An unrelated lesion of thymic lymphomas involving the SCID host thymus was seen in 12% of the mice. The data presented herein suggest that the SCID-rh is a valuable model for specific studies related to thymus-retrovirus interaction and that it could be used for further studies. The results are discussed in relation to current knowledge of thymus involvement during simian and human immunodeficiency virus infection.

Oxyurid parasites are common contaminants of laboratory rodents, and despite many described treatments, no method has assumed preeminence. Limitations in drug efficacy and the general inability to control for exposure to infective eggs are the primary contributors to treatment failure. In addition, some effective drugs must be eliminated from consideration because of narrow safety margins, other toxic aspects, or concerns related to particular uses of the experimental animals. As an alternative to currently described treatments or surgical derivation, we conducted an efficacy study against Syphacia muris in rats with a new fenbendazole-based protocol. Fenbendazole is a highly efficacious broad-spectrum anthelmintic with adulticidal, larvicidal, and ovicidal actions. Its pharmacokinetic behavior, ovicidal activity, and exceptionally wide safety margin in rats and mice make it an attractive choice for pinworm treatment. We used a 150-ppm medicated feed formulation to reach a targeted dose of 8.0 to 12.0 mg/kg/day in three separate studies designed to assess drug intake and efficacy under different housing conditions and in breeding and nonbreeding populations of ACI rats. In all cases, drug was given on alternating weeks, and nonbreeding populations were medicated for a cumulative period of 14 days. The same schedule was used for breeding populations, but the treatment was repeated after a 2-week rest period to ensure sufficient exposure for newly weaned animals. The results of our study indicate that our described treatment, in combination with environmental control measures against pinworm eggs, is capable of eliminating S. muris.

N-methyl-N-nitrosourea induces murine CD4-8+ T-lymphomas that express high levels of J11d and low levels of CD5 antigens, a phenotype characteristic of immature CD4-8+ thymocytes. This assignment is supported by the fact that CD4-8+ lymphoma cell lines acquire CD4 expression after intrathymic (i.t.) transfer, a finding consistent with the established precursor potential of the normal immature CD4-8+ subset. CD4+8+ lymphomas recovered after i.t. transfer maintain a CD4+8+ phenotype in long-term culture. Northern blot analyses reveal that CD4 expression is regulated at the transcriptional level in immature CD4-8+ and CD4+8+ cell lines. CD4-8+ lymphomas express low levels of functional CD3/TCR complexes that mediate intracellular Ca2+ mobilization in response to CD3 or alpha/beta-TCR monoclonal antibody. These data suggest that the immature CD4-8+ subset contains cells capable of undergoing TCR-mediated signaling and selection events. In contrast to normal immature CD4-8+ cells, which comprise a heterogeneous and transient subset, the CD4-8+ lymphoma lines provide stable, monoclonal models of the immature CD4-8+ stage of thymocyte development.

The desire to produce specific antibodies to substances available only in minute quantities and increased concern for laboratory animal welfare have each contributed to heightened interest in alternative immunization methods. In this report, we describe the production of polyclonal antibodies against microgram quantities of a weakly immunogenic tumor-associated protein of canine origin. Our technique employs the subcutaneous implantation of nitrocellulose electroblot strips without the use of adjuvant. The method is simple, appears reliable, can be used to improve antigen purity, and is applicable for either polyclonal or monoclonal antibody production in different host species. In addition, because traditional adjuvants are not required with this system, severe inflammatory responses and associated animal discomfort are reduced.