Changes in cyclic adenosine 3':5'-monophosphate-dependent protein kinases during the progression of urethan-induced mouse lung tumors

The cyclic adenosine 3':5'-monophosphate (cAMP)-dependent protein kinases in lung adenomas are functionally different from those of normal lung. The relevance of this change to neoplastic conversion was examined by comparing tumor kinases with those obtained from the normal cell of origin and by studying the kinases at different stages of tumor growth. Lung tumors were collected from A strain mice at different times after a single injection of urethan. These tumors are predominantly of alveolar type two cell origin, and cAMP-binding proteins in extracts from isolated type two cells and from lung adenomas at various stages of tumor progression were compared. Both the incorporation of the cAMP photoaffinity analogue, cyclic 8-azidoadenosine 3':5'-[32P]monophosphate (8-N3-[32P]cAMP), into the regulatory subunits of the type I (RI) and type II (RII) cAMP-dependent protein kinases and the autophosphorylation of RII were similar in extracts from whole normal lung and from type two cells. Altered protein kinases are thus not characteristic of normal type two cells. Lung tumors showed a decrease in photodetectable RII which correlated in degree with tumor size and extent of anaplasticity. This decreased RII photolabeling during tumor growth was associated with increased RII autophosphorylation. In contrast, decreased RII photolabeling in extracts from neonatal lung is accompanied by a substantial decrease in RII autophosphorylation. The characteristics of RII during normal development thus clearly differ from those during neoplastic development. An increase in the amount of an Mr 37,000 proteolytic fragment derived from R-subunits was also noted as a function of tumor progression. DEAE-cellulose chromatography of tumor cytosol showed that the increase in the amount of Mr 37,000 protein was accompanied by increased subunit dissociation of the type I isozyme. The dissociated RI subunit has been shown to be more sensitive to cleavage by a Ca2+-dependent neutral protease than when RI was in the holoenzyme form. This protease is present in both normal lung and lung adenomas, and its activity increases during the later stages of tumor progression. A comparison of cAMP binding and the light-induced covalent incorporation of 8-N3-[32P]cAMP showed that, for both RI and RII, photoincorporation was about 75% as efficient as noncovalent binding. In contrast, although the Mr 37,000 fragment can be photolabeled with low concentrations of 8-N3-[32P]cAMP, noncovalent cAMP binding to the endogenous Mr 37,000 fragment could not be demonstrated with a standard filtration assay. Such altered cAMP binding characteristics following Ca2+-dependent proteolysis of R-subunits would all     

Clustering of excess growth resources within leading growth cones underlies the recurrent “deposition” of varicosities along developing neurites

Varicosities (VRs) are ubiquitous neuronal structures that are considered to serve as presynaptic structures. The mechanisms of their assembly are unknown. Using cultured Aplysia neurons, we found that in the absence of postsynaptic targets, VRs form at the leading edge of extending neurites when anterogradely transported organelles accumulate within the palm of the growth cone (GC) at a rate that exceeds their utilization by the GC machinery. The aggregation of excess organelles at the palm of the GC leads to slowdown of the GC's advance. As the size of the organelle clusters increases, the rate of organelle sequestration diminishes and the supply of building blocks to the GC resumes. The GCs' advance is re-initiated, “leaving behind” an organelle-loaded nascent VR. These mechanisms account for the recurrent “deposition” of almost equally spaced VRs by advancing GCs. Consistent with the view that VRs serve as “ready-to-go” presynaptic terminals, we found that a short train of action potentials leads to exocytosis of labeled vesicles within the varicosities. We propose that the formation and spacing of VRs by advancing GCs is the default outcome of the balance between the rate of supply of growth-supporting resources and the usage of these resources by the GC's machinery at the leading edges of specific neurites.     

Testing responsiveness to change for the early childhood oral health impact scale (ECOHIS)

Abstract – Objectives: The Early Childhood Oral Health Impact Scale (ECOHIS) is a recently developed oral health‐related quality of life instrument designed to assess the impact of oral health problems in 0–5‐year‐old children. It has previously been validated as discriminative instrument. The goal of this study was to investigate the responsiveness to change of the ECOHIS. Methods: Data were collected from a convenience sample of 101 parents of 0–5‐year‐old children attending a hospital dental clinic for dental treatment. The ECOHIS was completed by parents prior to dental treatment and 2 weeks later. Subjects were also asked a global transition judgement concerning change between the second and first completion of the ECOHIS instrument. Responsiveness to change of the ECOHIS was analysed through: (i) a comparison of ECOHIS change scores with a global transition judgment by study subjects; (ii) an assessment of the statistical significance of within‐group change in scores over time for groups reporting improvement, stability and deterioration; (iii) an estimation of the ECOHIS’s sensitivity; and (iv) an investigation the effect size of the ECOHIS. Results: Of the 101 subjects recruited, 94 had full datasets. Their data were used for the analyses reported in this paper. Pre‐ and post‐treatment distributions of ECOHIS scores were strongly distributed towards no oral health impacts. Among the 94 subjects, 51.1% reported improvement, 42.6% reported no change and 6.4% reported deterioration following treatment, using the global transition judgement. The mean ECOHIS change scores for these three groups were ?0/9, +0.7 and +6.5 respectively, although none of the within‐group changes were statistically significant. The effect size for those reporting improvement was small (0.15) but for those reporting deterioration was moderate‐to‐large (0.69). Sensitivity ranged from 0.61–0.79 depending on the size of the cut‐off point, with a change of 3 points demonstrating the best sensitivity to false positive ratio (0.79 versus 0.41 respectively). Conclusion: In this sample with low levels of problems, the ECOHIS has demonstrated some limited ability to respond to change. Further work in a larger sample with higher levels of problems is needed to investigate the instrument’s ability to respond to change when it has occurred.     

HEEADSSS assessment for adolescents requiring anticoagulation therapy

The care of adolescents with complex chronic illness needs to be developmentally appropriate to encourage adherence, knowledge retention and self-management. There has been an increase in the number of adolescents requiring long-term or lifelong anticoagulation therapy, related to either an underlying illness or idiopathic deep vein thrombosis. The burden of anticoagulant therapy, the associated risks and the required lifestyle changes can significantly impact on psychosocial well-being in the adolescent patient. This review identifies issues pertinent to adolescent anticoagulation management and discusses strategies to support optimal management. The HEEADSSS (Home, Education and employment, Eating, Activities with peers, Drugs, Sexual activity, Suicide and depression, and Safety) framework was used to provide guidance in undertaking a psychosocial assessment of adolescents requiring anticoagulant therapy in conjunction with a structured education strategy. Adolescent anticoagulant management strategies employing developmentally appropriate assessment and education will likely result in improved therapeutic outcomes for the patient and potentially facilitate transition to adult-based care.     

Inhibition by erlotinib of primary lung adenocarcinoma at an early stage in male mice

PURPOSE: Erlotinib, a small molecule inhibitor of the tyrosine kinase (TK) domain of epidermal growth factor receptor (EGFR), increases survival of advanced non-small cell lung cancer patients who failed standard chemotherapy (Phase III study). We evaluated whether erlotinib is also effective at an early stage of primary lung tumorigenesis in a carcinogen-induced lung tumor model in mice. METHODS: Sixteen weeks after carcinogen (urethane) injection, when small self-contained adenomas are evident, male and female A/J mice were treated IP with 10 mg/kg erlotinib or Captisol vehicle daily over 3.5 weeks (15 mice per group). The efficacy, metabolism and mechanism of action of erlotinib were evaluated. RESULTS: Erlotinib reduced tumor burden in males by twofold compared to vehicle (12.7 +/- 1.2 vs 26.2 +/- 2.5 mg, respectively; p < 0.0001), while tumor burden in erlotinib-treated females slightly increased compared to vehicle by 21% (15.1 +/- 1.2 vs 11.9 +/- 0.9 mg, respectively; p < 0.05). Tumor multiplicity, in contrast, was unaffected by erlotinib. The levels of erlotinib that accumulated in plasma, lung tumor tissue and adjacent uninvolved (UI) lung were comparable in males and females. Males, however, accumulated more OSI-420, an active and pharmacologically equipotent metabolite of erlotinib, than females in plasma, lung tumors, and UI lung. In both genders, 80% of tumors contained Kras mutations at codon 61, but no EGFR mutations were detected. The cellular distribution and concentration of EGFR were also similar between genders. In control mice, however, phosphorylated EGFR (pEGFR) levels were nearly 2.5-fold higher in males compared to females in UI lungs and sevenfold higher in lung tumors. Further, erlotinib decreased the contents of pEGFR in UI lungs and lung tumors, particularly in males. CONCLUSIONS: Adenomas from male mice in this early lung cancer model are responsive to erlotinib treatment, possibly because of a greater dependence of male tumor growth on the EGFR pathway compared to females. Importantly, these results indicate that small lung adenomas from male mice that utilize EGFR signaling but also harbor Kras mutations shrink in response to erlotinib, suggesting that erlotinib may be beneficial for some patients very early during lung cancer progression.     

Prostaglandin fever in rats is altered by kainic acid lesions of the ventral septal area

The ventral septal area (VSA) has been shown to be a region within the rat brain where arginine vasopressin (AVP) acts to reduce fever. To test the hypothesis that destruction of this area would affect the magnitude of the febrile response, body temperature was monitored in male, Wistar rats given intracerebroventricular injections of prostaglandin E1 (200 ng) and saline (10 microliter) before and after bilateral injections of kainic acid (KA) or of saline vehicle into the VSA. While fever heights were unaffected by the lesion, fever in the KA-lesioned animals remained significantly elevated (P less than 0.05) for 1 h after the peak response. There was no significant difference in the fever responses displayed by sham-lesioned animals. The body temperature response of non-febrile animals to high or low ambient temperature was unaffected by the lesions. The enhanced fever following the KA lesion, but not sham lesions of the VSA would support the hypothesis that this region is involved in endogenous suppression of fever.     

The genetic basis of susceptibility to lung tumors in mice

This is the first in a series of review articles describing the current state of research on mouse lung tumorigenesis. The system is valuable as a biological model for studying stages of tumor development and the interaction of genetic and environmental factors which dispose towards neoplasia. Additionally, these tumors are analagous to bronchiolo-alveolar cancer in man. Three pulmonary adenoma susceptibility (Pas) genes regulate susceptibility; 1 of these is the proto-oncogene, K-ras2. Candidates for the other 2 genes include the H-2 histocompatibility locus and genes which regulate the basal proliferative rate of the cells from which these tumors arise. Tumor development is favored by a depressed immune system, immature age, and decreased levels of circulating corticosterone.     

Antigen B of the vaccine strains of Marek's disease virus and herpesvirus of turkeys presents heat-labile group and serotype specific epitopes

Summary Antigen B of Marek's disease virus (MDV) vaccine strains CVI988 and SB1 (serotypes 1 and 2) and herpesvirus of turkeys (HVT) (serotype 3) is formed of oligomeric molecules that are detergent-stable and heat-labile. Immunoblots of native membranal extracts of HVT- and MDV-infected chick embryo fibroblasts (CEF) probed with avian monoserotypic antisera, murine monoclonal antibodies (mAb) to the three serotypes and mAb to antigen B showed two distinct patterns of high molecular weight oligomeric antigens. Serotypes 1 and 3 vaccine viruses formed one set and serotype 2, the other. Avian monotypic sera to serotypes 1 and 3 viruses detected two high molecular weight bands of 230 and 300 kDa in MDV-1 and HVT-infected CEF but only a weak diffuse zone ranging from 130 to 230 kDa in extracts of SB1-infected CEF. No 300 kDa band was discernible in the SB1 extract when blotted with avian monotypic 1 and 3 antisera. MAbs to MDV serotypes 1 and 3 and to antigen B also detected the 230 and 300 kDa antigens, while the mAb to SB1 detected a 50 kDa antigen in the SB1-infected extract only. Furthermore, the antigen B mAb did not reveal high mol. wt. oligomers in SB1-infected CEF extracts. Antigen B oligomers were rapidly destroyed by heating at 95°C and the rate of denaturation of the 230 and 300 kDa oligomers differed for each of the three vaccine viruses. We propose that antigen B of MDV1 and HVT has a complex conformation created by juxtaposition of dimers (230–250 kDa) and trimers (300 kDa), and is inserted in the infected cell membrane so that conformational, discontinuous epitopes are formed in addition to continuous epitopes. It appears that HVT protects chickens against oncogenic strains of MDV1 by virtue of the cross reactivity of the conformational determinants located on these oligomers. Serotype 2 vaccine shares some of its antigenic determinants with serotypes 1 and 3, while its unique immunogenic features form the basis of the protective synergism achieved when serotypes 2 and 3 vaccines are combined together.