Molecular Evidence for Convergence and Parallelism in Evolution of Complex Brains of Cephalopod Molluscs: Insights from Visual Systems.

Coleoid cephalopods show remarkable evolutionary convergence with vertebrates in their neural organization, including (1) eyes and visual system with optic lobes, (2) specialized parts of the brain controlling learning and memory, such as vertical lobes, and (3) unique vasculature supporting such complexity of the central nervous system. We performed deep sequencing of eye transcriptomes of pygmy squids (Idiosepius paradoxus) and chambered nautiluses (Nautilus pompilius) to decipher the molecular basis of convergent evolution in cephalopods. RNA-seq was complemented by in situ hybridization to localize the expression of selected genes. We found three types of genomic innovations in the evolution of complex brains: (1) recruitment of novel genes into morphogenetic pathways, (2) recombination of various coding and regulatory regions of different genes, often called "evolutionary tinkering" or "co-option", and (3) duplication and divergence of genes. Massive recruitment of novel genes occurred in the evolution of the "camera" eye from nautilus' "pinhole" eye. We also showed that the type-2 co-option of transcription factors played important roles in the evolution of the lens and visual neurons. In summary, the cephalopod convergent morphological evolution of the camera eyes was driven by a mosaic of all types of gene recruitments. In addition, our analysis revealed unexpected variations of squids' opsins, retinochromes, and arrestins, providing more detailed information, valuable for further research on intra-ocular and extra-ocular photoreception of the cephalopods.

Activation of the Ah receptor signaling pathway by prostaglandins.

The aryl hydrocarbon receptor (AhR) is a ligand-dependent transcription factor that mediates many of the biological and toxicological actions of a diverse range of chemicals, including the environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, dioxin). Although no endogenous physiological ligand for the AhR has yet been described, numerous studies support the existence of such a ligand(s). Here we have examined the ability of prostaglandins and related chemicals to activate the AhR signaling system. Using two AhR-based bioassay systems we report that relatively high concentrations of several prostaglandins (namely, PGB3, PGD3, PGF3alpha, PGG2, PGH1, and PGH2) can not only stimulate AhR transformation and DNA binding in vitro, but also induce AhR-dependent reporter gene expression in mouse hepatoma cells in culture. PGG2 also induced AhR-dependent reporter gene expression to a level three-to four fold greater than that observed with a maximal inducing dose of TCDD. Sucrose gradient ligand binding analysis revealed that PGG2 could competitively displace [3H]TCDD from the AhR. Overall, our results demonstrate that selected prostaglandins are weak agonists for the AhR and they represent a structurally distinct and novel class of activator of the AhR signal transduction pathway.

Characterization of a maltose transport system in Clostridium acetobutylicum ATCC 824.

The utilization of maltose by Clostridium acetobutylicum ATCC 824 was investigated. Glucose was used preferentially to maltose, when both substrates were present in the medium. Maltose phosphoenolpyruvate (PEP)-dependent phosphotransferase system (PTS) activity was detected in extracts prepared from cultures grown on maltose, but not glucose or sucrose, as the sole carbon source. Extract fractionation and PTS reconstitution experiments revealed that the specificity for maltose is contained entirely within the membrane in this organism. A putative gene system for the maltose PTS was identified (from the C. acetobutylicum ATCC 824 genome sequence), encoding an enzyme II(Mal) and a maltose 6-phosphate hydrolase.

The nurse lecturer's role in mentoring the mentors.

AIM: This article reports on the results of a survey conducted early in 1999 investigating the effectiveness of current arrangements for mentor preparation and ongoing mentor support provided within adult placement areas within Greater Glasgow Health Board. METHOD: A sample of 150 mentors was surveyed with a response rate of 47 per cent (n = 71). RESULTS: Results indicate that although mentors are generally satisfied with the current approach to mentorship preparation, the issue of support from both managers and academic staff is problematic. CONCLUSION: Respondents indicated that they wished to see lecturers visiting the practice placement areas and providing support, particularly in relation to assessment of students. Also highlighted in this study is the need for more effective communication between placement areas and academic staff.

Ablation of ventricular tachycardia with a saline-cooled radiofrequency catheter: anatomic and histologic characteristics of the lesions in humans.

INTRODUCTION: In animal models, active cooling of the electrode during radiofrequency (RF) ablation allows creation of larger lesions, presumably by increasing the power that can be delivered without coagulum formation. These RF lesions have not been characterized in human myocardium in regions of infarction and scarring. METHODS AND RESULTS: Cooled-tip RF catheter ablation of ventricular tachycardias (VTs) was performed in two patients who had severe congestive heart failure and subsequently underwent cardiac transplantation. The first patient had four different monomorphic VTs. RF applications along the inferoseptal margin of a scarred region abolished all inducible VTs. The second patient had sarcoidosis involving the myocardium and four different inducible VTs. RF current applied at an inferobasal VT exit and at the right and left septa failed to abolish the VTs. The explanted hearts were examined at the time of cardiac transplantation 18 and 21 days later, respectively. Lesions extended to depths up to 7 mm, reaching clusters of myocardial cells deep to regions of fibrosis. Microscopically, the ablation sites contained coagulation necrosis with hemorrhage, surrounded by a rim of granulation tissue. CONCLUSION: Saline-irrigated RF catheter ablation produces relatively large lesions capable of penetrating deep into scarred myocardium.

Metastasizing mixed tumor of the parotid gland: a rare tumor with unusually rapid progression in a cardiac transplant recipient.

We report the case of a 69-year-old man who had a mixed tumor (pleomorphic adenoma) removed from his parotid gland 3 years after orthotopic heart transplantation. Two years later, he presented with widely metastatic mixed tumor, which resulted in his death within 6 months. Metastatic mixed tumor is histologically identical to a benign mixed tumor, but it inexplicably metastasizes. Such tumors are rare and have not been reported to date in a transplant recipient. This case illustrates the rapid and aggressive course that malignancies can follow in an immunosuppressed population. Mixed tumors are common salivary neoplasms, so transplant recipients should be carefully followed after resection for evidence of metastatic spread.

Graft arteriosclerosis-induced myocardial pathology in heart transplant recipients: predictive value of endomyocardial biopsy.

BACKGROUND: Ischemic myocardial pathology resulting from graft arteriosclerosis (GA) includes subendocardial myocyte vacuolization (SEMV), indicative of sublethal ischemic injury, and coagulative myocyte necrosis, acute and healing (CMN), indicative of infarction. METHODS: To assess the sensitivity and specificity of myocardial pathology resulting from GA in endomyocardial biopsy specimens, we correlated SEMV and CMN in the final three biopsy specimens (mean interval from last biopsy to death 23 +/- 20 days) with autopsy findings from 30 heart transplant recipients who survived more than 3 months and died of GA (n = 16) or of other causes (n = 14). The two groups were similar in other parameters. RESULTS: Myocardial ischemic injury was present at autopsy in all 16 patients with GA with the following distribution: SEMV (n = 13) nine right ventricle (RV) and left ventricle (LV), four LV only; focal CMN (n = 8) six RV and LV, two LV only; subendocardial infarct (n = 3) three LV only; and transmural infarct (n = 3) one RV, two LV. Ischemic injury was present in the RV of 11 of 16 patients with GA. Of patients without GA, one had SEMV at autopsy; none had infarcts. Ischemic myocardial pathology was present in 10 of 48 biopsy specimens from patients with GA compared with one of 41 biopsy specimens from patients without GA (p < 0.05). The specificity of SEMV on biopsy was 98%, but sensitivity was only 17%. The positive predictive value for ischemic injury was 92%, and negative predictive value was 51%. CONCLUSIONS: Myocardial pathology resulting from ischemia was present at autopsy in all patients dying of GA. Although more prevalent in the LV, 69% of patients had ischemic myocardial pathology in the RV, where it may be accessible to biopsy. Ischemic myocardial pathology in biopsy specimens is highly specific but far less sensitive, for diagnosing GA.

Enhanced lymphocyte longevity and absence of proliferation and lymphocyte apoptosis in Quilty effects of human heart allografts.

"Quilty effect" (QE) is a common and problematic observation in endomyocardial biopsy specimens from patients after cardiac transplantation. The origin, fate, and significance of QE cellular elements are unknown. Twenty-six paraffin-embedded endomyocardial biopsy specimens with QE (five QE As and twenty-one QE Bs) from twenty-two cardiac allografts were studied by immunohistochemistry for expression of Bcl-2, Fas antigen, proliferating cell nuclear antigen (PCNA), perforin, T cells (UCHL-1), macrophages (CD68), and apoptosis by in situ terminal deoxyribonucleotide transferase (TdT)-mediated dUTP nick end labeling (TUNEL). Approximately 50% of the lymphocytes present, mainly in the deeper region of 20 of 21 QE Bs and all 5 QE As, expressed Bcl-2 in a pseudo-nodular pattern surrounding high endothelial venules. Fas expression was detected in lymphocytes in 20 of 21 QE Bs and 5 QE As in a similar pattern to Bcl-2. However, endothelial cells and macrophages were Bcl-2 negative, whereas both cell types were Fas positive. Perforin was negative in nearly all lymphocytes. TUNEL staining revealed that lymphocytes in QEs did not undergo apoptosis; however, TUNEL positivity was observed in approximately 70% of endothelial cells and macrophages and certain adjacent cardiac myocytes in 20 of 21 QE Bs and 5 QE As. One large QE B with a germinal center was noted. Germinal center cells expressed PCNA intensely but were negative for Bcl-2, Fas, and TUNEL. Cells surrounding the germinal center expressed abundant Bcl-2. The following conclusions were drawn. 1) Apoptosis does not occur in lymphocytes in QE where enhanced Bcl-2 (apoptosis inhibitor) and Fas antigen (apoptosis inducer) are expressed. 2) PCNA negativity indicates that QE lymphocytes may not proliferate, and perforin negativity indicates that they may not exhibit perforin-based cytotoxicity. We propose that there may be a relationship between the longevity of lymphocytes in QE and the absence of apoptosis.

The challenge of endomyocardial biopsy interpretation in assessing cardiac allograft rejection.

The endomyocardial biopsy has long been the preferred technique for monitoring the rejection status of the cardiac allograft. During the past year, published reports have addressed important issues concerning the endomyocardial biopsy, including the reliability of the International Society for Heart and Lung Transplantation grading system; problem areas in posttransplantation biopsy interpretation, including grade 2 rejection and myocyte injury, Quilty lesions, and ischemic injury; the natural history of grade 2 rejection; the necessity of surveillance biopsies late in the posttransplantation course; and the efficacy of numerous noninvasive techniques in diagnosing or predicting rejection. No technique developed to date has been shown to have the sensitivity or specificity needed to replace the endomyocardial biopsy as a diagnostic tool. In addition, studies of endomyocardial biopsy specimens have furthered our understanding of the pathobiology of rejection and other transplant-related conditions.

Prominence of apolipoproteins B, (a), and E in the intimae of coronary arteries in transplanted human hearts: geographic relationship to vessel wall proteoglycans.

BACKGROUND: Transplant arteriopathy (TA) is characterized by vessel wall thickening with prominent glycosaminoglycan and lipid deposits. In this light, we have recently demonstrated the distribution of proteoglycans in allograft coronary arteries. The aim of this study is to examine the distribution of apolipoproteins within allograft coronary arteries and to investigate their localization in relation to proteoglycans. METHOD: Particular transverse sections of left and right epicardial coronary arteries from 46 human cardiac allografts, 11 normal hearts, and 11 hearts with native atherosclerosis were stained immunohistochemically for apolipoprotein B, apolipoprotein (a) (apo[a]), apolipoprotein E (apoE), biglycan, decorin, and versican by use of an automated immunostainer. RESULTS: Apo(a) and apoE immunopositivity in TA was much more intense than that in native atherosclerosis, whereas the reverse was true for apoB. Prominent apoE deposits were evident circumferentially in endothelia and extracellularly in superficial intima of mildly diseased TA, as well as in deeper intima of severely diseased TA. Apo(a) had a staining pattern very similar to apoE except for a patchy deposition also seen in TA media. The intimal areas staining prominently with apoE or apo(a) in TA arteries corresponded very closely to the areas with proteoglycan deposits, especially versican. CONCLUSION: The distinctive patterns of apolipoprotein accumulation in TA and native atherosclefosis appear to reflect different pathogenetic processes in the two conditions. The colocalization of proteoglycans and apolipoproteins in TA intima supports the hypothesis that interactions between proteoglycans and apolipoproteins influence lipid retention and overload in allograft coronary arteries.

Biglycan, decorin, and versican protein expression patterns in coronary arteriopathy of human cardiac allograft: distinctness as compared to native atherosclerosis.

BACKGROUND: Histochemical staining has demonstrated previously dramatic deposits of glycosaminoglycans associated with prominent lipid accumulations in thickened vessel walls of allograft coronary arteries. In this study, we characterized the amount, distribution, and types of proteoglycan in the walls of coronary arteries from human cardiac allografts and from native atherosclerotic (NA) controls as part of a strategy to understand the pathogenesis of transplant arteriopathy (TA). METHOD: We used polyclonal rabbit antibodies against human biglycan, decorin, and versican localize the proteoglycan molecules in standardized transverse sections of the proximal left anterior descending and right coronary arteries. Slides were scored in a blinded fashion for intensity of proteoglycan staining (0 to 6+) and for localization in the vessel walls. RESULTS: Unique patterns of proteoglycan distribution were present in TA and NA. Biglycan was particularly prominent in intima and evolving atheromata in severely diseased TA coronary arteries, but not in NA. Decorin was present mainly in adventitia of all vessels and in the intima of NA. Prominent versican accumulation occurred in intima and media of TA coronaries, associated with smooth muscle cells and foam cells. There was a reciprocal pattern of biglycan and decorin staining. Versican colocalized with biglycan. Intimal biglycan and versican deposits were positively correlated to the extent of luminal narrowing in TA. CONCLUSION: The distinctive staining patterns for biglycan, decorin and versican in both native and allograft disease indicate that the synthesis and distribution of these proteoglycans are regulated by different local mechanisms in different atheromatous diseases.

Consistencies and controversies in the application of the International Society for Heart and Lung Transplantation working formulation for heart transplant biopsy specimens. Rapamycin Cardiac Rejection Treatment Trial Pathologists.

BACKGROUND: The International Society for Heart and Lung Transplantation (ISHLT) working formulation was proposed in 1990 to promote standardization in the interpretation of endomyocardial biopsy specimens obtained after heart transplantation, especially in the setting of multicenter clinical trials and for publication purposes. METHODS: To assess uniformity in interpretation, 16 pathologists experienced in posttransplant endomyocardial biopsy specimen interpretation each read independently, in randomized order, an identical series of 23 biopsy specimens representing all ISHLT grades of rejection (n = 12) and other posttransplant biopsy findings (n = 11). The pathologists represented heart transplantation centers participating in the Rapamycin Treatment Trial for Grades 2 and 3A Rejection. The index diagnosis in each case was determined by two pathology consultants who had concurred blindly on 22 of 23 (96%) biopsy specimen evaluations on their first independent reading. Discrepancies that would not affect clinical response (for example grades 0 versus 1A, 1A versus 1B, 3A versus 3B, 3B versus 4) were considered minor; those that could alter therapy were considered major. RESULTS: The 16 trial pathologists were in exact agreement with the index diagnosis in 17 (mean) +/- 3 biopsy specimens (range 10 to 22) and 20 (mean) +/- 2 biopsy specimens (range 16 to 22) if minor discrepancies were excluded. Of 368 diagnoses rendered, 265 agreed exactly with the index diagnosis and 103 differed, of which 50 were minor discrepancies. The 53 major discrepancies included grades 1A/B versus 2, 22 discrepancies; 2 versus 3A, 11; Quilty B versus 2/3A, 10; biopsy site versus 3A, 2; ischemic injury versus 3A/B, 2; Toxoplasma versus 3A, 2; posttransplantation lymphoproliferative disorder versus 3B/4, 3; and Quilty B versus posttransplantation lymphoproliferative disorder, 1. Interobserver agreement assessed by weighted kappa values was 0.67. CONCLUSIONS: First, there was agreement among the trial pathologists and the index diagnosis (excluding minor discrepancies) in 85% of biopsy specimen interpretations. Second, of 53 major discrepancies, 43 (81%) involved grades 1A/B versus 2, 2 versus 3A, and Quilty B versus 2/3A. Third, in 54% of instances in which biopsy findings other than rejection were misdiagnosed as rejection grades, the grade was sufficiently high to have adverse treatment implications. Fourth, the ISHLT working formulation provides for a high degree of diagnostic consistency among experienced observers, and concordance could be further enhanced by clarification of criteria for grade 2 rejection and Quilty B lesions.

Human transplant coronary artery disease: pathological evidence for Fas-mediated apoptotic cytotoxicity in allograft arteriopathy.

Cytotoxicity mediated by cytolytic T cells occurs exclusively through Fas- and perforin-based pathways. Such mechanisms may be important in transplant coronary artery disease (TxCAD). We studied Fas and perforin expression and apoptosis using immunohistochemical methods, in situ terminal deoxyribonucleotide transferase-mediated dUTP nick-end labeling (TUNEL), and morphologic analysis of vessels with TxCAD taken from 12 transplant patients, which we compared with vessels of 10 patients with native coronary artery disease (CAD) and vessels from 14 patients with normal coronary arteries. Fas was detected in all TxCAD specimens. Fas-positive cells were mainly endothelial cells (EC); 100% of EC and approximately one-third of T cells and macrophages were positive for Fas. Almost all TUNEL-positive cells were Fas-expressing cells. Of the T cells and macrophages that expressed Fas, 18% appeared apoptotic in the mild and moderate-to-severe TxCAD group as compared with 78% in severe TxCAD patients (p = 0.0124). By contrast, EC damage was less evident in the vessels with greater intimal disease severity: 10% in severe TxCAD versus 75% in the mild and moderate-to-severe TxCAD group (p = 0.0122). Perforin was positive in 5% of the total intimal T cells in 3 of 12 arteriopathy specimens. Fas and perforin were virtually negative in vessels taken from CAD patients. TUNEL was diffusely positive in CD68-positive foam cells in the lipid-rich core, but Fas was negative in all CAD specimens. In normal arteries, 8 of 14 specimens contained a few TUNEL-positive and Fas-positive EC and T cells. Perforin was negative. We conclude that EC damage in TxCAD seems to be brought about through a Fas-based apoptotic pathway and that CD4-positive cytolytic T cells may be the major lytic cells involved in TxCAD.

Heart transplantation-associated perioperative ischemic myocardial injury. Morphological features and clinical significance.

BACKGROUND: The frequency and clinical significance of perioperative ischemic myocardial injury (PIMI) after heart transplantation and the diagnostic features distinguishing PIMI from rejection are not well defined. METHODS AND RESULTS: We evaluated PIMI in the first four weekly endomyocardial biopsies and/or autopsy myocardium from 140 consecutive orthotopic heart transplantation recipients (1984 to 1991) by grading the severity of coagulative myocyte necrosis (CMN) as absent, 0; mild-focal, 1; moderate-multifocal, 2; or severe-confluent, 3, and determining the evolution of morphological features of its healing. CMN (often with contraction bands) was noted in 124 patients (89%); 24 patients (17%) had grade 3 CMN, of which 4 died within 30 days of transplantation. Nevertheless, at 1 year after surgery, survival was similar in patients with and without severe injury. Increased cold ischemic time but neither donor age nor intensity of inotropic support correlated with more severe early ischemic injury. PIMI inflammation was characterized by a predominantly polymorphonuclear/histiocytic infiltrate that contained lymphocytes and plasma cells, expanding the interstitium but not encroaching upon and separable from adjacent viable myocytes. Histological features of PIMI developed and resolved more slowly than those of typical myocardial infarct necrosis in nonimmunosuppressed patients; at 4 weeks, CMN persisted in 20% of patients and residual healing in nearly half. Diagnostic rejection was observed concurrently with PIMI in 54 of 533 biopsies (10%). CONCLUSIONS: Diagnosed by conventional histological criteria, PIMI is prevalent early after heart transplantation and has a protracted healing phase that can mimic or coexist with rejection. Extensive PIMI has deleterious impact on short-term survival, but the long-term impact of PIMI remains to be established.