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Introduction: Zambia is experiencing a critical shortage of radiologists responsible for interpreting X-ray images. Nine radiologists serve the entire population of over 18 million people. Consequently, referring physicians can receive reports late and often receive X-ray images without radiological reports attached, which may lead to delayed diagnoses and treatment of critically injured patients. This challenge could be alleviated if radiographers could assist with interpreting X-ray images. This study was undertaken to subject a cohort of Zambian radiographers to a training intervention, however, the COVID-19 pandemic necessitated using a novel approach to the intervention by delivering the training mainly through social media but also through face-to-face lectures., Methods: A cohort of 27 radiographers employed at eight public hospitals in the Copperbelt Province of Zambia undertook a training intervention using face-to-face training and image discussions on the social media WhatsApp® platform. The participants underwent a pre-and post-test in which they were asked to interpret 20 adult trauma CXR images. For the training intervention, the radiographers attended a face-to-face image interpretation lecture, after which they received training images with a radiologist report weekly for eight weeks via the WhatsApp® platform. Participants were encouraged to discuss and pose questions via the platform., Results: The cohort of radiographers (n = 27) showed an improvement in their interpretation skills for trauma CXR images. The interpretation median scores ranged from approximately 82% to 93% in the pre-test and 85% to 97% in the post-test. The Wilcoxon signed-rank tests revealed significant differences in the interpretation ability skills for 12 of the 20 CXR images after the 8-week training, demonstrating the successful implementation of the program. When comparing three categories of radiographers' years of experience (1-5; >5-10; and >10 years), the Kruskal Wallis test could not identify significant differences in the CXR image interpretation skills among the different categories of experience (P = 0.1616). When comparing the interpretation skills of radiographers working at the three different hospital levels (Level 3 with a full-time radiologist and more than ten radiographers; Level 1 and 2 without a full-time radiologist; Level 2 with six to ten radiographers; and Level 1 with five or less radiographers), the Kruskal Wallis test revealed that the level of the hospital where the radiographers were employed significantly influenced their skills to interpret the CXR images (P = 0.0323)., Conclusion: This type of novel training intervention is urgently required in the Copperbelt Province of Zambia. The results show that the training process was implemented successfully to improve radiographers' image interpretation skills of adult trauma CXR images., Implications for Practice: Promoting radiographers' involvement in image interpretation will likely improve imaging services in Zambia, considering the critical shortage of radiologists., (Copyright © 2024. Published by Elsevier Inc.)

Background Aims: The targeting of solid cancers with chimeric antigen receptor (CAR) T cells faces many technological hurdles, including selection of optimal target antigens. Promising pre-clinical and clinical data of CAR T-cell activity have emerged from targeting surface antigens such as GD2 and B7H3 in childhood cancer neuroblastoma. Anaplastic lymphoma kinase (ALK) is expressed in a majority of neuroblastomas at low antigen density but is largely absent from healthy tissues., Methods: To explore an alternate target antigen for neuroblastoma CAR T-cell therapy, the authors generated and screened a single-chain variable fragment library targeting ALK extracellular domain to make a panel of new anti-ALK CAR T-cell constructs., Results: A lead novel CAR T-cell construct was capable of specific cytotoxicity against neuroblastoma cells expressing low levels of ALK, but with only weak cytokine and proliferative T-cell responses. To explore strategies for amplifying ALK CAR T cells, the authors generated a co-CAR approach in which T cells received signal 1 from a first-generation ALK construct and signal 2 from anti-B7H3 or GD2 chimeric co-stimulatory receptors. The co-CAR approach successfully demonstrated the ability to avoid targeting single-antigen-positive targets as a strategy for mitigating on-target off-tumor toxicity., Conclusions: These data provide further proof of concept for ALK as a neuroblastoma CAR T-cell target., Competing Interests: Declaration of Competing Interest The authors have no commercial, proprietary or financial interest in the products or companies described in this article., (Copyright © 2022 International Society for Cell & Gene Therapy. Published by Elsevier Inc. All rights reserved.)

Introduction: The safety and effectiveness of prehospital clinical c-spine clearance or spinal motion restriction (SMR) decision support tools are unclear. The present study aimed to examine the available literature on clinical cervical spine clearance and selective SMR decision support tools to identify possible barriers to implementation, safety, and effectiveness when used by emergency medical service (EMS) practitioners., Method: We performed a focused scoping review of published literature on the prehospital use of clinical c-spine clearance and SMR decision tools in adult blunt trauma patients. The Medline, Embase, Cochrane Library, Cumulative Index of Nursing and Allied Health Literature, Web of Science, Turning Research into Practice and EBSCOhost online databases were searched (February 2021). The type of decision support tool and facilitators and barriers to its use were extracted from each included publication in accordance with a modified descriptive-analytical framework. Extracted data were subjected to thematic analysis., Results: Following screening, forty-two articles were included in this scoping review. No studies conducted specifically in low resource settings were found. The majority of articles (57%) evaluated the use of specific SMR decision support tools, such as the National Emergency X-Radiography Utilization Study (NEXUS) and the Canadian C-spine Rule (CCR). Potential facilitators of safe and effective use were identified in 60%, and potential barriers to safe and effective use in 55% of included articles. Only one study evaluated the CCR when used by EMS practitioners, making it difficult to determine its appropriateness for implementation in the prehospital setting., Conclusion: This is the first scoping review, to our knowledge, that has attempted to identify the possible barriers and facilitators to their implementation, safety, and effectiveness when used by EMS practitioners. Key issues identified included terminology, guideline compliance and implementation, and a lack of context-specific evidence. These may provide important considerations for future guideline development., Competing Interests: The authors declare no conflict of interest, (© 2022 The Authors. Published by Elsevier B.V. on behalf of African Federation for Emergency Medicine.)

This guide was designed to provide a foundation for developing paediatric diagnostic reference levels (PiDRLs) for conventional radiography. In principle, the calculation of diagnostic reference levels (DRLs) is recommended for diagnostic x-ray imaging examinations for radiosensitive patients, such as paediatric patients. PiDRLs are fundamentally important when considering dose optimisation in diagnostic radiology, computed tomography and interventional radiology for paediatric patients. DRLs can assist to point to non-optimised practices and the improvement of paediatric dose optimisation. The purpose of this continuing medical education article is to give medical radiation professionals an overview of PiDRLs for conventional radiography, an understanding of the benefits, the data collection process and some of the calculation methods. The readers can use these steps to establish and implement PiDRLs for different examinations., (Copyright © 2021. Published by Elsevier Inc.)

Introduction: The aim of this study was to compare the diagnostic contribution of the standard lateral and coned lumbar vertebra five and sacral vertebra one (L5/S1) projection in diagnostic radiology for specific pathologies in the digital era., Methods: The study used a retrospective qualitative design through a systematic stepwise process. The steps included a retrospective analysis of lumbar spine radiology reports over 20 months. The objective of this step was to identify the most common lumbar spine pathologies observed among the source population records (N=354). A radiologist identified five different pathologies on standard lateral and coned lateral L5/S1 projections (n=96). Fischer's exact test was performed to examine the significance of the association between the standard lateral and coned lateral L5/S1 projection classifications for each of the top five lumbar spine pathologies separately., Results: The five most prevalent lumbar spine pathologies indicated were degenerative disc disease (n=235; 66.4%), disc space narrowing (n=175; 49.4%), osteophytes (n=92; 26.0%), endplate sclerosis 19.21% (n=68; =9.2%) and malalignment (n=61; 17.2%). The Fisher's exact test executed to compare the top five lumbar spine pathologies visible on the standard lateral and coned lateral L5/S1 indicated that except for endplate sclerosis (p=0.0023), no significant difference in additional diagnostic information was observed between the standard lateral and coned lateral L5/S1 projections at α=0.05., Conclusion: Compared to the standard lateral projection, the coned lateral L5/S1 projection did not contribute statistically significant additional diagnostic information for specific lumbar spine pathologies in the digital era., (Copyright © 2021. Published by Elsevier Inc.)

The heavy polycyclic aromatic hydrocarbons (HPAHs) cause detrimental effects to hydrocracker operations by deactivating the catalysts and depositing in the downstream of the reactor/ exchangers. Therefore, it is essential to continuously monitor the accumulation of HPAHs in a hydrocracker unit. To accurately measure the concentration of HPAHs, the development of a fast and reliable analytical method is inevitable. In this work, an analytical method based on non-aqueous reversed phase chromatography in combination with high resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was developed. As a first step, five different types of stationary phases were evaluated for the separation of HPAHs in non-aqueous mode and the best suited phase was further used for the fractionation of HPAHs in a fractionator bottom sample obtained from a refinery hydrocracker unit. The eight major fractions or peaks obtained from the separation were further characterized by UV spectroscopy and FT-ICR MS and the compounds in the fractions were tentatively confirmed as benzoperylene, coronene, methylcoronene, naphthenocoronene, benzocoronene, dibenzoperylene, naphthocoronene and ovalene. The developed liquid chromatography method can be easily adapted in a refinery laboratory for the quantitation of HPAHs in hydrocracking products. The method was further tested to check the interference of sulfur aromatics and/or large alkylated aromatic hydrocarbons on the determination of HPAHs in hydrocracking products., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Intermittent sunburns, particularly in childhood, are the strongest environmental risk factor for malignant melanoma (MM). In mice, a single neonatal UVR exposure induces MM, whereas chronic doses to adult mice do not. Neonatal UVR alters melanocyte migration dynamics by inducing their movement upward out of hair follicles into the epidermis. UVR is known to induce inflammation and recruitment of macrophages into the skin. In this study, we have used a liposomal clodronate strategy to deplete macrophages at the time of neonatal UVR, and have shown functionally that this reduces the melanocyte proliferative response. This effect was not reproduced by depletion of CD11c-expressing populations of dendritic cells. On the basis of epidermal expression array data at various time points after UVR, we selected mouse strains defective in various aspects of macrophage recruitment, activation, and effector functions, and measured their melanocyte UVR response. We identified Ly6c(low)MHCII(hi) macrophages as the major population promoting the melanocyte response across multiple strains. The activity of this subpopulation was CCR2 (C-C chemokine receptor type 2) independent and partly IL-17 dependent. By helping induce this effect, the infiltration of specific macrophage subpopulations after sunburn may be a factor in increasing the risk of subsequent neoplastic transformation of melanocytes.

Melanocytes respond to UVR not only by producing melanin, but also by proliferating. This is essentially a protective response. We have studied the melanocyte proliferative response after a single UVR exposure to neonatal mice. At 3 days post-UVR in wild-type neonates we observed a marked melanocyte activation not seen in adults. Melanocytes migrated to the epidermal basal layer, their numbers peaking at 3-5 days after UVR then diminishing. They appeared to emanate from the hair follicle, migrating to the epidermis via the outer root sheath. In melanoma-prone mice with melanocyte-specific overexpression of Hras(G12V), basal layer melanocytes were increased in size and dendricity compared to UVR-treated wild-type mice. Melanocytes in mice carrying a pRb pathway cell-cycle defect (oncogenic Cdk4(R24C)) did not show an enhanced response to UVR such as those carrying Hras(G12V). The exquisite sensitivity to UVR-induced proliferation and migration that characterizes neonatal mouse melanocytes may partly explain the utility of this form of exposure for inducing melanoma in mice that carry oncogenic mutations.

To ascertain the influence of vitamin D3 and its metabolites on the function of the skin immune system and the induction of the contact hypersensitivity (CHS) response, a population of vitamin D3-deficient BALB/c mice was established, through dietary vitamin D3 restriction and limitation of exposure to UVB irradiation. Vitamin D3 normal female mice had higher CHS responses than their male counterparts, and dietary vitamin D3 deficiency significantly increased the CHS responses in male, but not in female, mice. This change in the vitamin D3-deficient male mice was not due to an alteration in skin dendritic cell function including antigen carriage, migration or costimulatory molecule expression. In addition, 18 h after sensitisation, the lymph node populations in the vitamin D3-deficient and normal male mice showed similar proliferation and IFN-gamma production. However, during the sensitisation phase of CHS, there was lower lymphocyte recruitment to the skin draining lymph nodes of the vitamin D3-deficient and normal male mice compared with their female counterparts which could account for the difference between the sexes in the extent of the CHS response. These results indicate the vitamin D system can influence cutaneous immune responses in male mice, but this did not occur through the modulation of the dendritic cell functions analysed.

To assess the premise that genetically determined differences in susceptibility to UV-induced immunosuppression are reflected in UV carcinogenesis, we investigated UV skin cancer induction in two strains of reciprocal F1 hybrid mice CB6F1 males with high susceptibility to UV immunosuppression and a BALB/c X-chromosome and B6CF1 males with low susceptibility to UV immunosuppression and a C57BL/6 X-chromosome. Four experimental groups comprising both strains treated three times weekly with two UV regimens (daily doses incremented from 2.25 to 6 or 4.5 to 12 kJ per m2) were monitored for skin tumor development. Survival without a skin tumor differed over the four groups (p < 0.0001) and differed according to UV regimen within each strain (p < 0.0005). Differences between strains were significant for the higher dose (p = 0.03) but not for the lower dose (p = 0.19) of UV, suggesting a dose-strain interaction. Comparing the higher UV dose regimen to the lower UV dose regimen within a strain at three reference points, tumor-free survival was reduced significantly more (p < 0.05) in the CB6F1 mice than in the B6CF1 mice. Histologic assessment of all tumors revealed fibrosarcomas, squamous carcinomas, and mixed tumors. Immunohistochemistry of the mixed tumors for vimentin, keratin, and E-cadherin confirmed the presence of squamous and fibrosarcomatous elements. The enhanced susceptibility to UV carcinogenesis of CB6F1 males treated with the higher UV protocol was attributable to a significantly enhanced proportion (p < 0.005) of mixed tumors. Analysis of the data by comparing the proportion of animals tumor free at three reference time points confirmed a dose-strain interaction only in the development of mixed tumors, putatively the malignantly advanced carcinomas (p < 0.03). A dose-strain interaction was also observed for systemic UV immunosuppression of contact hypersensitivity (p < 0.025). These findings support the concept that genetic differences in susceptibility to UV-induced immunosuppression may be a risk factor for skin cancer.

Autoimmune gastritis develops in 20-60% of BALB/c mice following thymectomy at 3 days after birth (3dnTx). Previously we identified the gastric H+/K+ ATPase as the causative autoantigen and mapped the immunoreactive T cell epitope to a carboxyl-terminal peptide on the gastric H+/K+ ATPase beta subunit. Here we show that autoimmune gastritis can be suppressed by immunizing 3dnTx mice through neonatal skin with the beta subunit peptide, in combination with the contact sensitizer TNCB. When spleen cells were transferred from suppressed mice to nude mice a proportion of recipient mice developed gastritis. These results indicate that pathogenic T cells were still present in the 3dnTx mice but the absence of gastritis indicates that their activity can be regulated following induction of cutaneous tolerance by immunizing through neonatal skin. We propose that cutaneous tolerance is induced through mediation of immature Langerhans cells in neonatal skin and that this tolerance prevented the autoreactivity of pathogenic T cells. This procedure will have implications for strategies to suppress autoimmunity., (Copyright 2001 Academic Press.)

Skin cells containing excessive ultraviolet (UV) radiation-induced DNA damage are eliminated by apoptosis that involves the p53 pathway and Fas/Fas-Ligand (Fas-L) interactions. To determine whether dysregulation of apoptosis plays a role in skin cancer development through disruption of Fas/Fas-L interactions, hairless SKH-hr1 mice were exposed to chronic UV irradiation from Kodacel-filtered FS40 lamps for 30 weeks. Their skin was analyzed for the presence of sunburn cells (apoptotic keratinocytes) and for Fas and Fas-L expression at various time points. A dramatic decrease in the numbers of morphologically identified sunburn cells and TUNEL-positive cells was detected as early as 1 week after chronic UV exposure began. After 4 weeks of chronic UV exposure, these cells were barely detectable. This defect in apoptosis was paralleled by an initial decrease in Fas-L expression during the first week of chronic UV irradiation and a complete loss of expression after 4 weeks. Fas expression, however, increased during the course of chronic UV exposure. p53 mutations were detected in the UV-irradiated epidermis as early as 1 week after irradiation began and continued to accumulate with further UV exposure. Mice exposed to chronic UV began to develop skin tumors after approximately 8 weeks, and all mice had multiple skin tumors by 24 weeks. Most of the tumors expressed Fas but not Fas-L. We conclude that chronic UV exposure may induce a loss of Fas-L expression and a gain in p53 mutations, leading to dysregulation of apoptosis, expansion of mutated keratinocytes, and initiation of skin cancer.

We examined the effects of ultraviolet (UV) radiation on the time course for induction of sunburn (apoptotic) cells and expression of proteins known to be associated with growth arrest and apoptosis in SKH-hr1 mouse skin. Mice were irradiated with a single dose (2.5 kJ/m(2)) of UV from Kodacel-filtered (290-400 nm) FS40 sunlamps and the skin tissues were analyzed at various times after irradiation for the presence of apoptotic cells and expression of p53, p21(Waf-1/Cip1), bcl-2, bax, and proliferating cell nuclear antigen. The results indicated that p53 expression was induced early in the epidermis, reaching maximum levels 12 hours after irradiaton, and p21(Waf-1/Cip1) expression in the epidermis peaked at 24 hours after irradiation. In contrast, UV radiation induced high levels of bax at 24 to 72 hours after irradiation with a concomitant decrease in bcl-2 expression. Coinciding with these changes, apoptotic cells began to appear 6 hours after irradiation and reached a maximum at 24 hours after irradiation. Interestingly, proliferating cell nuclear antigen expression, which was initially confined to the basal layer, became dispersed throughout the basal and suprabasal layers of the skin at 48 hours and paralleled marked hyperplasia. These results suggest that UV irradiation of mouse skin induces apoptosis mediated by the p53/p21/bax/bcl-2 pathway and that the dead cells are replaced by hyperproliferative cells, leading to epidermal hyperplasia. This implies that UV-induced apoptosis and hyperplasia are closely linked and tightly regulated and that dysregulation of these two events may lead to skin cancer development.

We studied the dynamics of injected contrast enhancement in implanted VX2 tumors in rabbit thigh muscle. We compared two contrast agents Gd-DTPA and NMS60, a novel gadolinium containing trimer of molecular weight 2.1 kd. T1-weighted spin echo images were acquired preinjection and at 5-60 min after i.v. injection of 0.1 mmol/kg of agent. Dynamic T1-weighted SPGR images (1.9 s/image) were acquired during the bolus injection. Male NZW rabbits (n = 13) were implanted with approximately 2 x 10(6) VX2 tumor cells and grew tumors of 28+/-27 mL over 12 to 21 days. NMS60 showed significantly greater peak enhancement in muscle, tumor rim, and core compared to DTPA in both T1-weighted and SPGR images. NMS60 also showed delayed peak enhancement in the dynamic scans (compared to Gd-DTPA) and significantly reduced leakage rate constant into the extravascular space for tumor rim (K21 = 5.1 min(-1) vs. 11.5 min(-1) based on a 2 compartment kinetic model). The intermediate weight contrast agent NMS60 offers greater tumor enhancement than Gd-DTPA and may offer improved regional differentiation on the basis of vascular permeability in tumors.

Depletion of epidermal Langerhans cells (LC) and the concomitant depression of the skin immune system after excessive exposure to ultraviolet B light (UVB) has been established in the international literature for some time. Our investigations were intended to determine whether or not these phenomena occurred as a direct result of increased LC migration being triggered by the UVB exposure. To test this hypothesis, a sheep model was established in which the lymphatic vessels draining a defined region of skin were cannulated and the cells migrating towards the regional lymph node continuously collected. Cell populations in these collections were identified and enumerated by indirect immunofluorescence and flow cytometry. These experiments showed there was a significant, dose-dependent increase in the rate of LC migration from sheep skin after exposure to doses of UVB light exceeding 1 minimal erythemal dose (MED). In a series of parallel experiments, the functional characteristics of dendritic cells (DC) migrating from normal or UVB irradiated sheep were studied. To assay them, enriched preparations of DC were collected via cannulated afferent lymphatic vessels and pulsed with antigen prior to incubation with autologous peripheral blood lymphocytes. The relative efficiency of antigen presentation was determined by the ability of DC to induce T cell proliferation. Our data clearly demonstrate that there is a profound loss of normal antigen-presenting cell function after exposure to UVB light. Various experiments were undertaken to determine the mechanism(s) associated with these changes in migration kinetics and cellular function. Electron microscopic examinations of LC migrating from normal or UVB irradiated skin have demonstrated a profound loss of dendritic processes after UVB exposure. This provides a possible explanation for the changes in skin immunity after UVB exposure.

BALB/c mice thymectomized 3 days after birth (3dnTx) are prone to the development of autoimmune gastritis. As this outcome may be a consequence of altered immunoregulatory mechanisms, we set out to determine the immunological status of these mice and their capacity to acquire antigen-specific peripheral tolerance. The latter was assessed by the capacity of these mice to suppress a contact sensitivity response to 2,4,6-trinitrochlorobenzene (TNCB) following treatment of the skin by the carcinogen, DMBA. The 3dnTx mice had a reduced number of CD4(+) and CD8(+) T cells and a reduced lymphocyte proliferative response to PHA, but a normal contact sensitivity response to TNCB. After treatment of the skin with DMBA these mice failed to develop contact sensitivity to TNCB. Adoptive transfer of splenocytes from these mice to naive mice transfered antigen-specific suppression, irrespective of whether the 3dnTx mice had developed autoimmune gastritis. We conclude that despite thymectomy at day 3 and the attendant immunosuppression, the capacity of BALB/c mice to generate antigen-specific peripheral tolerance to TNCB was retained. These results suggest that precursor T cells which mediate suppression to antigens such as TNCB are present in 3dnTx mice and that these cells are likely to have developed in the thymus and exported to the periphery before 3 days after birth., (Copyright 1998 Academic Press.)

Experimental autoimmune encephalomyelitis in the common marmoset, a nonhuman primate species (Callithrix jacchus), is a new model for multiple sclerosis. Given the close immunological relationship between marmosets and humans, it is an attractive model for investigating immunopathological pathways relevant to multiple sclerosis and to evaluate new treatments for the disease. Unlike in the originally documented model, experimental autoimmune encephalomyelitis induced without the use of Bordetella pertussis led to a chronic disease of moderate severity. The clinical course of experimental autoimmune encephalomyelitis in the present model was mainly chronic and progressive, but periods of incomplete remission did occur. At the chronic stage of the disease, actively demyelinating lesions were found together with inactive demyelinated and remyelinated (shadow) plaques. Before immunization and during clinically active experimental autoimmune encephalomyelitis, T1- and T2-weighted magnetic resonance brain images were obtained. Correlation of the data from the magnetic resonance images and the neuropathology analysis revealed that the hyperintense regions in T2-weighted images represented both active and inactive remyelinating lesions. Quantification showed that the number of lesions in T2-weighted magnetic resonance images equalled those found by pathological examination, and thus T2-weighted magnetic resonance imaging can be used to discern the total lesion load. Extravasation of gadolinium-diethylenetriamine-penta-acetic acid (triple dose) was found only in lesions, which by histopathology were shown to be engaged in the process of active demyelination.

Objectives: To investigate the influence of mesothelial cell (MC) seeding on patency and neointimal formation of small diameter ePTFE grafts in a canine model., Materials and Methods: MC were isolated from the omentum, cultured, seeded on fibronectin-coated ePTFE grafts (4 cm, 4 mm ID), and implanted in the carotid artery of five Beagle dogs. Each dog also received a non-seeded control graft. Patency was assessed by palpation immediately after implantation, and non-invasively by magnetic resonance angiography (MRA) after 1 week and just prior to sacrifice (4 weeks). Intimal thickness was quantified on histological sections by use of computer-aided morphometry., Results: All grafts were patent after implantation. After 1 week, MRA showed the loss of lumen diameter in two seeded grafts. After 4 weeks, two seeded grafts were occluded, one seeded graft was severely stenosed, and all others were without angiographic lumen reduction. Histology and morphometry confirmed that two seeded grafts were occluded, and demonstrated that the other three seeded grafts showed significantly more intima formation (0.22-1.34 mm) than the control grafts (< 0.08 mm; p < 0.01)., Conclusions: The MC seeding process decreases patency and increases neointimal formation of small diameter ePTFE grafts in dogs and does not seem to be useful for reduction of graft thrombogenicity.

The activation of T cells through presentation of antigen by dendritic cells (DC) relies on many factors, including the correct balance of cytokines in the immediate microenvironment. Antigen presentation by DC migrating from carcinogen-treated skin is impaired as evidenced by the failure of antigen-pulsed DC to initiate specific T cell proliferation. To elucidate mechanism(s) of DC dysfunction, DC migrating from carcinogen-treated skin were collected, pulsed with OVA, and cultured with antigen-specific autologous lymphocytes. Supernatants were assayed for the costimulatory cytokine IL-1 beta which influences the outcome of DC:T cell interactions. The dendritic cells migrating from carcinogen-treated skin that failed to induce T cell proliferation were unable to produce IL-1 beta. This may account for the abrogation of DC function following exposure to chemical carcinogens and provides an explanation for the inability of DC to induce a protective immune response to carcinogen-induced tumours.

In vivo 1H-NMR imaging was employed to study dynamic changes in the status of tissue water as a function of time after mechanical brain injury induced by partial unilateral transection of the fimbria fornix (FF) in the rat brain and was correlated with histology. Changes in the brain tissue were reproducibly found in distinct regions which were exclusively located in the lesioned hemisphere. The most pronounced changes concerned the lateral ventricle. Ventricular enlargement became evident posterior to the site of transection after a few hours and was maximal after 2-4 days. At later time points the posterior ventricular expansion was reduced. The lateral ventricle anterior to the site of transection was significantly enlarged from day 1 and continued to expand for up to 7 months. Tissue response at the site of transection, mainly involving the hippocampal formation and the thalamus, was first manifested after 24 h, while signs of progressive tissue degeneration were apparent in the long term.

Chemical carcinogens reduce cutaneous immunity, an event accompanied by alterations to the number and morphology of the resident epidermal Langerhans cell (LC) population. This study aimed to examine the functional capacity of LC and other dendritic cells (DC) that are migrating from carcinogen-treated skin via afferent lymphatic vessels. Generation and subsequent cannulation of prefemoral pseudoafferent lymphatic vessels in sheep allowed continuous collection of DC migrating from a defined area of carcinogen-treated skin. The ability of metrizamide-enriched afferent lymph DC to present antigen to autologous primed peripheral blood lymphocytes was used as an indicator of DC function. Topical application of the complete carcinogens 7,12-dimethylbenz[a]anthracene and benzo[a]pyrene abrogated the stimulatory capacity of migrating DC for periods of 8 weeks and 5 weeks, respectively, whereas the tumor promoter 12-O-tetradecanoylphorbol-13-acetate reduced DC function for less than 1 week. These findings favor tumor development in carcinogen-treated skin being enhanced due to impairment of DC immunological surveillance.

Exposure of murine skin to suberythemal doses of ultraviolet-B (UVB) radiation before contact sensitization alters the activity of antigen-presenting cells (APC) in the draining lymph nodes (DLN), decreases the contact hypersensitivity (CHS) response, and induces hapten-specific Ts cells. We determined whether in vivo UVB irradiation alters the ability of hapten-bearing APC from the DLN to form clusters with hapten-specific T lymphocytes. When APC from UV-irradiated, fluorescein isothiocyanate (FITC)-sensitized mice were mixed with a FITC-specific T-cell line, significantly fewer clusters formed compared with FITC+ APC from unirradiated mice. A higher percentage of clusters formed with APC from UV-irradiated mice were Mac-1+ and bound both CD4+ and CD8+ T cells, whereas FITC+ APC from nonirradiated mice bound CD4+ cells. These results suggest that UVB irradiation interferes with the induction of CHS by altering the functional interaction between APC and T cells, perhaps by altering the population of APC in the skin.

Treatment of skin with the chemical carcinogen 7,12-dimethylbenz[a]anthracene (DMBA), which reduces the density of epidermal class II MHC-expressing Langerhans cells (LC), enhances its survival when transplanted onto histoincompatible hosts. We have examined the ability of T lymphocytes which reject DMBA-treated skin to lyse P388D1 cells expressing either only class I or class I and II antigens. Lymphocytes isolated from solvent-treated grafts showed greater cytotoxicity for the targets expressing both antigens, indicating that some of these lymphocytes were specific for class II MHC antigens. In contrast, lymphocytes isolated from carcinogen-treated grafts lysed both targets similarly and hence did not contain any cells specific for class II MHC antigens. Anti-class I MHC antibody blocked cytotoxicity by both leukocyte populations to similar extents, but anti-class II MHC antibodies preferentially blocked T cells isolated from the solvent-treated grafts. There was no difference in the phenotype of the cytotoxic cells isolated from solvent- and carcinogen-treated grafts. Thus, whereas solvent-treated skin grafts are rejected by T cells specific for class I and II MHC antigens, DMBA-treated skin grafts are only rejected by class I MHC-specific T cells which may account for the enhanced survival of the carcinogen-treated grafts.

To define the mechanism(s) of carcinogen depletion of Langerhans cells (LC) from skin, the migration of LC from the skin to the regional lymph node was examined in carcinogen-treated, antigen-treated, and control sheep. This was assessed by cannulation of afferent lymphatic vessels that drain the treated areas of skin or the efferent lymphatic draining the regional lymph node. Cells draining from test or control skin were continuously collected and enumerated by indirect immunofluorescence and flow cytometry using specific anti-CD1 monoclonal antibodies. There was a marked increase in the rate of LC migration in the 8 h following the application of the contact sensitizing antigen trinitrochlorobenzene (TNCB). The chemical carcinogen 7,12-dimethylbenz(a)anthracene (DMBA) triggered a tenfold-greater migration of LC compared with TNCB--with the peak response at 5 d. After DMBA treatment LC were also detected in the efferent lymph of the regional lymph node. It is concluded that the depletion of LC from carcinogen-treated skin is due to the increased LC migration and not carcinogen-induced cell death.

This study demonstrates that the xenobiotic product, 1-(o-chlorophenyl)-1-(p-chlorophenyl)-2,2-dichloro-3-13C-propane can be monitored in the liver of an intact animal by in vivo 13C surface coil NMR spectroscopy after intraperitoneal administration. The carbon-13 label could be detected after a single dose of only 200 mg/kg of the product. The intrahepatic changes of the signal intensity of the labeled product were monitored as a function of time. No signals corresponding to metabolites could be detected.

Comparison of the effectiveness of various gastrointestinal (GI) contrast agents for magnetic resonance (MR) imaging is often complicated by varying amounts intraluminal filling with the orally administered agents. To achieve more uniform and reproducible imaging results with GI contrast agents for MR imaging (GICMR), we evaluated a radiographic method for monitoring intraluminal filling and distribution. Solutions of Mn-DPDP (2 mM), to which a small amount of barium sulfate (6 wt/vol%) was added, were administered orally to dogs. Gastric emptying and small bowel transit were monitored fluoroscopically. MR imaging was performed either 1) at a fixed time after administration of the contrast agent or 2) at a variable interval when the contrast agent was observed fluoroscopically to be in the terminal ileum. When initiation of MR imaging was guided by fluoroscopic monitoring of intestinal contrast distribution, uniform and reproducible intestinal contrast enhancement by GICMR was achieved. However, when MR imaging was performed at a fixed time interval after oral administration, non-uniform and variable GI visualization was obtained, and this corresponded to the variable intestinal distribution observed fluoroscopically. We conclude that reproducible intestinal filling with orally administered contrast agents can be accomplished with a radiographic monitoring technique, and this promotes more consistent GI visualization on MR images. Such standardized and reproducible methods are necessary for studies in which the effectiveness of GI contrast media for MR imaging is evaluated and compared.

A new hepatobiliary contrast agent (Mn-DPDP) was used in the detection of liver metastases in six rabbits with seven hepatic V2 carcinomas. This contrast agent is derived from pyridoxyl-5-phosphate which is biomimetically designed to be secreted by the hepatocyte. After Mn-DPDP administration, a 105% increase in liver signal to noise was obtained using a 200/20 (TR/TE) pulsing sequence, and a 62% decrease in intensity was observed using a 1200/60 pulsing sequence. Liver V2 carcinoma contrast enhancement increased 427% using the 200/20 pulsing sequence and 176% using the 1200/60 pulsing sequence. Four of seven V2 carcinomas were not detectable prior to the administration of Mn-DPDP (50 mumol/kg). Two neoplasms were only detectable in retrospect (after Mn-DPDP) on the 1200/60 sequence. The smallest neoplasms detected in this study were 1-4 mm. Mn-DPDP appears to be a promising MRI contrast agent.

Application to skin depleted of LC by treatment with the chemical carcinogen DMBA of a dose of contact sensitizer optimal for inducing contact sensitivity activates transferrable suppressor cells. Excision of solvent- or DMBA-treated skin at various times following application of the contact sensitizer DNFB indicated that the fraction of antigen which leaves the skin within the first few hours induces tolerance. An initial signal inducing unresponsiveness, observed within 1/2 hr, was overturned 3-6 hr later. A more permanent tolerogenic signal in the DMBA- but not solvent-treated lymph node resulted from an epidermal cell from DMBA-treated skin presenting antigen to suppressor cells. Therefore it is likely that suppressor cells are activated in DMBA-treated mice by an epidermal cell which migrates to the local lymph node. Local lymph node cells from DMBA-treated mice also have a diminished ability to present antigen in vivo but they do not activate suppressor cells.

In two cases of routine Le Fort I osteotomy in secondary cleft palate surgery, a swelling noted in the antral mucosa was biopsied. In both cases, histological examination resulted in a diagnosis of odontogenic myxoma. After analysis of the radiographs, it was concluded that the biopsies were taken from displaced tooth germs. The close histological similarity between myxoma on the one hand and dental papilla tissue, a thickened tooth follicle and a thickened or polypoid antral mucosal lining on the other is discussed.

Since treatment of mouse skin with the chemical carcinogen 7,12-dimethylbenz[alpha]anthracene (DMBA) substantially decreases the density of cutaneous Langerhans cells (LC), the immune status of mice sensitized to 2,4-dinitrofluorobenzene (DNFB) through DMBA-treated skin was investigated. Mice did not develop contact sensitivity to DNFB when applied to DMBA-treated dorsal trunk skin, whereas sensitization resulted when DNFB was applied to untreated abdominal wall skin. Mice immunized with DNFB via DMBA-treated skin did not respond to subsequent immunization through untreated dorsal trunk skin, demonstrating the generation of suppressor cells which could inhibit the activation of effector lymphocytes. Adoptively transferred spleen cells from mice immunized with DNFB through DMBA-treated skin inhibited the response of sensitized hosts, indicating the presence of efferently acting suppressor cells which could inhibit the function of effector lymphocytes. This study has demonstrated that sensitization via skin depleted of LC by chemical carcinogen treatment induces an active state of tolerance rather than immunity.

The injection of chicken and sheep red blood cells (CRBC and SRBC) into rat popliteal lymph nodes either together or sequentially 2, 4, 6, or 8 days apart resulted in an enhanced immune response when the second antigen was injected 2 or 4 days after the injection of the first antigen (antigenic promotion) or a suppressed immune response when the second antigen was injected 6 days after the injection of the first antigen (antigenic competition). The immune response to either antigen was dependent upon the time of administration of the second antigen with respect to the first antigen. Lymphocyte migration into antigenically stimulated lymph nodes was greater when the two antigens were injected sequentially rather than together. Further, the migration of lymphocytes into the lymph node was enhanced when the second antigen was injected during the inductive or suppressive phase of the immune response to the first antigen (CRBC) regardless of whether the same (CRBC) or an antigenically unrelated antigen (SRBC) was used as the second antigen. While antigenic promotion may in part be explained by the increased rate at which lymphocytes migrate into lymph nodes, lymphocyte migration is also enhanced during antigenic competition. This suggests that while suppressor cells/factors may regulate the effector phase of an immune response they do not directly modulate the migration of blood-borne lymphocytes into the lymph node.

A tubular or sac-like structure with a well defined lumen which occasionally contained parasites was found in the outer muscle wall of the small and large intestine in 32 out of 40 male and 35 of 40 female marsupial mice of the two species, Antechinus swainsonii and Antechinus stuartii (Macleay). A similar structure was also found in the muscle layers of the stomach in 5 marsupial mice of both species. The cellular matrix of the structure appeared to be composed of randomly organized macrophage-like cells and in one case there was evidence of an inflammatory reaction to parasites within the lumen. The origin of this tube is either vestigial or the result of reactive changes.

Application of 2,4-dinitrofluorobenzene (DNFB) to BALB/c mouse skin depleted of epidermal Langerhans cells (LC) by the chemical carcinogen 7,12-dimethylbenz[a]anthracene (DMBA) activated cells which suppress both contact sensitivity and antibody production when transferred into naive host mice. Tolerance was induced by a concentration of DNFB optimal for inducing contact sensitivity in solvent-treated control mice. The cellular and humoral responses of hosts to a second antigen, 2,4,6-trinitrochlorobenzene (TNCB), were unaffected by these suppressor cells, demonstrating specificity for DNFB. Suppressor cells for cellular and humoral immunity could still be demonstrated 6 months following activation, by which time some mice had died, presumably of old age. The dose responses to sensitizer for generation of cells which suppressed contact sensitivity and antibody production differed, indicating that separate populations of suppressor cells probably inhibit these responses. Hence, during cutaneous chemical carcinogenesis, depletion of LC may allow activation of specific long-lived suppressor cells capable of inhibiting cellular or humoral antitumor immune responses.

Most cases of hairy cell leukemia represent malignancies of B cells. However, recent findings suggest that there is a spectrum of functional capacities within the entity hairy cell leukemia. Two patients with hairy cell leukemia, whose malignant cells in the peripheral blood showed both T- and B-cell features, are reported. The malignant cells of the spleens showed only B-cell characteristics. The hairy cells of both patients did not adhere to glass and lacked the la antigen. Both patients showed pronounced polyclonal hypergammaglobulinemia and developed frank leukemic blood pictures after splenectomy. Within the spectrum of hairy cell leukemia, these two cases probably represent a distinct subtype.

A method is presented to determine albumin and immunoglobulin G (IgG) in serum and cerebrospinal fluid (CSF) with an automatic discrete analyser. Concentrations of albumin and IgG in serum and CSF are compared with values obtained by radial immunodiffusion (RID). Ratios of albumin in CSF over albumin in serum and the so-called IgG index are calculated. Ratios obtained with the discrete analyser and with the RID are compared and discussed with respect to clinical diagnosis.

The entry of radiolabeled blood-borne T and B lymphocytes into resting popliteal lymph nodes and popliteal lymph nodes stimulated with semiallogeneic lymphocytes was investigated in rats. Thoracic duct lymphocytes separated into T- and B-lymphocyte populations on nylon-wool columns were radiolabeled with 51chromium and equal numbers of T or B lymphocytes were injected intravenously. While the ratio of T and B lymphocytes in the blood is approximately 3:1 it was found that the ratio of T to B lymphocytes migrating into lymph nodes was approximately 9 T to 1 B lymphocyte in both resting and antigenically stimulated lymph nodes. Since the ratio of T to B lymphocytes in thoracic duct lymph is similar to that of blood, there is a disparity between the number of T cells entering and leaving lymph nodes. These results suggest that some T lymphocytes may return to the blood directly and/or there is increased T lymphocyte death in lymph nodes.