Final Study Report of Andexanet Alfa for Major Bleeding With Factor Xa Inhibitors

BACKGROUND

Andexanet alfa is a modified recombinant inactive factor Xa (FXa) designed to reverse FXa inhibitors. ANNEXA-4 (Andexanet Alfa, a Novel Antidote to the Anticoagulation Effects of Factor Xa Inhibitors) was a multicenter, prospective, phase-3b/4, single-group cohort study that evaluated andexanet alfa in patients with acute major bleeding. The results of the final analyses are presented.

METHODS

Patients with acute major bleeding within 18 hours of FXa inhibitor administration were enrolled. Co-primary end points were anti-FXa activity change from baseline during andexanet alfa treatment and excellent or good hemostatic efficacy, defined by a scale used in previous reversal studies, at 12 hours. The efficacy population included patients with baseline anti-FXa activity levels above predefined thresholds (≥75 ng/mL for apixaban and rivaroxaban, ≥40 ng/mL for edoxaban, and ≥0.25 IU/mL for enoxaparin; reported in the same units used for calibrators) who were adjudicated as meeting major bleeding criteria (modified International Society of Thrombosis and Haemostasis definition). The safety population included all patients. Major bleeding criteria, hemostatic efficacy, thrombotic events (stratified by occurring before or after restart of either prophylactic [ie, a lower dose, for prevention rather than treatment] or full-dose oral anticoagulation), and deaths were assessed by an independent adjudication committee. Median endogenous thrombin potential at baseline and across the follow-up period was a secondary outcome.

RESULTS

There were 479 patients enrolled (mean age, 78 years; 54% male, 86% White; 81% anticoagulated for atrial fibrillation at a median time of 11.4 hours since last dose, with 245 (51%) on apixaban, 176 (37%) on rivaroxaban, 36 (8%) on edoxaban, and 22 (5%) on enoxaparin. Bleeding was predominantly intracranial (n=331 [69%]) or gastrointestinal (n=109 [23%]). In evaluable apixaban patients (n=172), median anti-FXa activity decreased from 146.9 ng/mL to 10.0 ng/mL (reduction, 93% [95% CI, 94-93]); in rivaroxaban patients (n=132), it decreased from 214.6 ng/mL to 10.8 ng/mL (94% [95% CI, 95-93]); in edoxaban patients (n=28), it decreased from 121.1 ng/mL to 24.4 ng/mL (71% [95% CI, 82-65); and in enoxaparin patients (n=17), it decreased from 0.48 IU/mL to 0.11 IU/mL (75% [95% CI, 79-67]). Excellent or good hemostasis occurred in 274 of 342 evaluable patients (80% [95% CI, 75-84]). In the safety population, thrombotic events occurred in 50 patients (10%); in 16 patients, this occurred during treatment with prophylactic anticoagulation that began after the bleeding event. No thrombotic episodes occurred after oral anticoagulation restart. Specific to certain populations, reduction of anti-FXa activity from baseline to nadir significantly predicted hemostatic efficacy in patients with intracranial hemorrhage (area under the receiver operating characteristic curve, 0.62 [95% CI, 0.54-0.70]) and correlated with lower mortality in patients <75 years of age (adjusted P=0.022; unadjusted P=0.003). Median endogenous thrombin potential was within the normal range by the end of andexanet alfa bolus through 24 hours for all FXa inhibitors.

CONCLUSIONS

In patients with major bleeding associated with the use of FXa inhibitors, treatment with andexanet alfa reduced anti-FXa activity and was associated with good or excellent hemostatic efficacy in 80% of patients.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT02329327.

Toxicity and differential oxidative stress effects on zebrafish larvae following exposure to toxins from the okadaic acid group

Okadaic acid-group (OA-group) is a set of lipophilic toxins produced only in seawater by species of the Dinophysis and Prorocentrum genera, and characterized globally by being associated with harmful algal blooms (HABs). The diarrhetic shellfish poisoning toxins okadaic acid (OA) and dinophysistoxin-1 (DTX-1) are the most prevalent toxic analogues making up the OA-group, which jeopardize environmental safety and human health through consumption of hydrobiological organisms contaminated with these toxins that produce diarrhetic shellfish poisoning (DSP) syndrome in humans. Consequently, a regulatory limit of 160 μg of OA-group/kg was established for marine resources (bivalves). The aim of this study was to investigate effects varying concentrations of 1-15 μg/ml OA or DTX-1 on toxicity, development, and oxidative damage in zebrafish larvae (Danio rerio). After determining the lethal concentration 50 (LC₅₀) in zebrafish larvae of 10 and 7 μg/ml (24 h) and effective concentration 50 (EC₅₀) of 8 and 6 μg/ml (24 h), different concentrations (5, 6.5, or 8 μg/ml of OA and 4, 4.5, or 6 μg/ml of DTX-1) were used to examine the effects of these toxins on oxidative damage to larvae at different time points between 24 and 120 hpf. Macroscopic evaluation during the exposure period showed alterations in zebrafish including pericardial edema, cyclopia, shortening in the anteroposterior axis, and developmental delay. The activity levels of biochemical biomarkers superoxide dismutase (SOD) and catalase (CAT) demonstrated a concentration-dependent decrease while glutathione peroxidase (GPx) and glutathione reductase (GR) were markedly elevated. In addition, increased levels of oxidative damage (malondialdehyde and carbonyl content) were detected following toxin exposure. Data demonstrate that high concentrations of OA and DTX-1produced pathological damage in the early stages of development <48 h post-fertilization (hpf) associated with oxidative damage.

Application of Chitosan and Chondroitin Sulphate Aerogels in a Patient With Diabetes With an Open Forefoot Transmetatarsal Amputation

INTRODUCTION

Diabetic foot ulcers may lead to nontraumatic amputations of the foot, leading to a decrease in patient quality of life. Transmetatarsal amputations (TMAs) represent an effective surgical procedure in cases of severe foot infection, but the tissue reconstruction is complicated and additional procedures should be considered. The present case report evaluates the wound closure of an open TMA in a patient with diabetes treated with a new aerogel composed of chitosan (ChS) and chondroitin sulphate (CS), without needing a skin graft.

CASE REPORT

A 72-year-old man with diabetes and a history of successive amputations was admitted to a hospital in Valdivia, Chile, due to a severe infection of toes 2 and 4 of the right foot. After the diagnosis of gangrene and osteomyelitis, the patient underwent a TMA of his right forefoot. The surgeon proposed the incorporation of ChS and CS aerogels to accelerate wound healing to avoid another surgical procedure. The TMA surgical wound area closed 50% after day 28 from starting treatment with aerogels. Complete closure was achieved at day 94 of treatment with aerogels, with good epithelial tissue and favorable cosmetic results and without residual limb deformities. The patient experienced minimal physical and psychological impairment from the procedure. Other surgical procedures were not necessary.

CONCLUSIONS

Due to the results of this patient, use of ChS and CS aerogels could represent an alternative treatment for forefoot TMA wound closure and prevent further surgical procedures, such as skin grafting. Future works should consider a larger number of cases.

Cell migration driven by substrate deformation gradients

Identifying the cues followed by cells is key to understand processes as embryonic development, tissue homeostasis, or several pathological conditions. Based on a durotaxis model, it is shown that cells moving on predeformed thin elastic membrane follow the direction of increasing strain of the substrate. This mechanism, straintaxis, does not distinguish the origin of the strain, but the active stresses produce large strains on cells or tissues being used as substrates. Hence, straintaxis is the natural realization of duratoaxis in vivo. Considering a circular geometry for the substrate cells, it is shown that if the annular component of the active stress component increases with the radial distance, cells migrate toward the substrate cell borders. With appropriate estimation for the different parameters, the migration speeds are similar to those obtained in recent experiments (Reig et al 2017 Nat. Commun. 8 15431). In these, during the annual killifish epiboly, deep cells that move in contact with the epithelial enveloping cell layer (EVL), migrate toward the EVL cell borders with speeds of microns per minute.

Ionic Nanocomplexes of Hyaluronic Acid and Polyarginine to Form Solid Materials: A Green Methodology to Obtain Sponges with Biomedical Potential

We report on the design, development, characterization, and a preliminary cellular evaluation of a novel solid material. This material is composed of low-molecular-weight hyaluronic acid (LMWHA) and polyarginine (PArg), which generate aqueous ionic nanocomplexes (INC) that are then freeze-dried to create the final product. Different ratios of LMWHA/PArg were selected to elaborate INC, the size and zeta potential of which ranged from 100 to 200 nm and +25 to -43 mV, respectively. Turbidimetry and nanoparticle concentration analyses demonstrated the high capacity of the INC to interact with increasing concentrations of LMWHA, improving the yield of production of the nanostructures. Interestingly, once the selected formulations of INC were freeze-dried, only those comprising a larger excess of LMWHA could form reproducible sponge formulations, as seen with the naked eye. This optical behavior was consistent with the scanning transmission electron microscopy (STEM) images, which showed a tendency of the particles to agglomerate when an excess of LMWHA was present. Mechanical characterization evidenced low stiffness in the materials, attributed to the low density and high porosity. A preliminary cellular evaluation in a fibroblast cell line (RMF-EG) evidenced the concentration range where swollen formulations did not affect cell proliferation (93-464 µM) at 24, 48, or 72 h. Considering that the reproducible sponge formulations were elaborated following inexpensive and non-contaminant methods and comprised bioactive components, we postulate them with potential for biomedical purposes. Additionally, this systematic study provides important information to design reproducible porous solid materials using ionic nanocomplexes.

Aerogels made of chitosan and chondroitin sulfate at high degree of neutralization: Biological properties toward wound healing

In this study, highly neutralized, highly porous, and ultralight polymeric aerogels prepared from aqueous colloidal suspensions of chitosan (CS) and chondroitin sulfate (ChS) nanocomplexes, formulated as quasi-equimolar amounts of both, are described. These aerogels were designed as healing agents under the inspiration of minimizing the amount of matter applied to wounds, reducing the electrostatic potential of the material and avoiding covalent cross-linkers in order to decrease metabolic stress over wounds. Aerogels synthesized under these criteria are biocompatible and provide specific properties for the induction of wound healing. They do not affect neither the metabolic activity of cultured 3T3 fibroblasts nor the biochemical parameters of experimental animals, open wounds close significantly faster and, unlike control wounds, complete reepithelialization and scarring can be attained 14 days after surgery. Because of its hydration abilities, rapid adaptation to the wound bed and the early accelerator effect of wound closure, the CS/ChS aerogels appear to be functional inducers of the healing. Previous information show that CS/ChS aerogels improve wound bed quality, increase granulation tissue and have pain suppressive effect. CS/ChS aerogels are useful as safe, inexpensive and easy to handle materials for topical applications, such as skin chronic wounds. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2464-2471, 2018.

Antibacterial activity against Staphylococcus aureus of chitosan/chondroitin sulfate nanocomplex aerogels alone and enriched with erythromycin and elephant garlic (Allium ampeloprasum L. var. ampeloprasum) extract

The antibacterial activity against Staphylococcus aureus of aerogels fabricated from colloidal suspensions of chitosan/chondroitin sulfate nanocomplexes is analyzed. Upon freeze-drying the colloidal suspensions, the aerogels presented a porous structure made of microsheets and microfibers. The aerogels could, in addition, be loaded with antimicrobial agents. Loaded with the antibiotic erythromycin, the aerogels showed crystalline deposits, affecting the topography of the samples as well as their mechanical properties, showing a decrease on the apparent Young’s modulus and hardness at 40% deformation. Loaded with elephant garlic (Allium ampeloprasum L. var. ampeloprasum) extract, the aerogels showed texturization of the microsheets and microfibers, and the higher relative mass allowed an increase on the apparent Young’s modulus and hardness at 40% deformation with respect to pristine aerogels. Unloaded aerogels showed activity against Staphylococcus aureus, including a methicillin-resistant strain. The release of erythromycin from the aerogels to an agar environment is governed by equilibrium forces with the polysaccharides, which allow modulating the load of antibiotic and its concomitant diffusion from the material. The diffusion of the active components of the elephant garlic extract did not show a dependence on the polysaccharide content, revealing a week interaction. The elephant garlic extract resulted active against the methicillin-resistant Staphylococcus aureus strain, while resistance was found for the antibiotic, revealing the therapeutic potential of the natural extract. The antimicrobial aerogels may be used for several therapeutic purposes, such as healing of infected chronic wounds.

Chitosan/chondroitin sulfate aerogels with high polymeric electroneutralization degree: formation and mechanical properties

The formation of ultralight, highly porous solid materials (porosity higher than 99%) containing equivalent molar amounts of chitosan (CS) and chondroitin sulfate (ChS) is presented. First, we show protocols to produce colloidal suspensions of assembled polymer nanocomplexes by simultaneously mixing equimolar amounts of the oppositely charged polysaccharides, preventing macroprecipitation. The colloidal suspensions were then freeze-dried to form the active aerogels. Apparent density in the order of 100–101 mg/cm3 was achieved. The materials show low stiffness (Young’s modulus of about 2 kPa), which make them easy to handle for clinical applications, and easy to compress, pack, store and transport. These characteristics promote them as cheap, safe and biodegradable materials able to be used for several therapeutic purposes, such as wound healing.

A Simple Mathematical Model for Wound Closure Evaluation

The incidence of ulcers associated to type 2 diabetes mellitus (T2DM) increases every year. We introduce and explore a new mathematical algorithm to evaluate wound-healing in foot ulcers associated to T2DM. Fifteen patients (nine women and six men), mean age of 70 ± 16 years were included. The evolution of their wounds followed-up for a period of 18-45 days. According to the Wagner grading system the ulcers were grade I (5 patients), grade II (9 patients), and grade III (1 patient). Clinically, the type of the ulcers was neuroischemic (12 patients) and neuropathic (3 patients). A new parameter is introduced, the "continuous linear healing rate" Dc that was more accurate with higher values and requires less quantifications than usual formulas to make a wound-healing projection.

Activation of the human keratinocyte B1 bradykinin receptor induces expression and secretion of metalloproteases 2 and 9 by transactivation of epidermal growth factor receptor

The B1 bradykinin receptor (BDKRB1) is a component of the kinin cascade localized in the human skin. Some of the effects produced by stimulation of BDKRB1 depend on transactivation of epidermal growth factor receptor (EGFR), but the mechanisms involved in this process have not been clarified yet. The primary purpose of this study was to determine the effect of a BDKRB1 agonist on wound healing in a mouse model and the migration and secretion of metalloproteases 2 and 9 from human HaCaT keratinocytes and delineate the signalling pathways that triggered their secretion. Although stimulation of BDKRB1 induces weak chemotactic migration of keratinocytes and wound closure in an in vitro scratch-wound assay, the BDKRB1 agonist improved wound closure in a mouse model. BDKRB1 stimulation triggers synthesis and secretion of both metalloproteases, effects that depend on the activity of EGFR and subsequent phosphorylation of ERK1/2 and p38 mitogen-activated protein kinases and PI3K/Akt. In the mouse model, immunoreactivity for both gelatinases was concentrated around wound borders. EGFR transactivation by BDKRB1 agonist involves Src kinases family and ADAM17. In addition to extracellular matrix degradation, metalloproteases 2 and 9 regulate cell migration and differentiation, cell functions that are associated with the role of BDKRB1 in keratinocyte differentiation. Considering that BDKRB1 is up-regulated by inflammation and/or by cytokines that are abundant in the inflammatory milieu, more stable BDKRB1 agonists may be of therapeutic value to modulate wound healing.

[Commitment and development of competences in clinical research in residency training programs in Chile]

BACKGROUND

In Chile, residency training programs (RTP) take place in a stimulating academic environment for the promotion of clinical research skills. However, research is not a frequent curricular outcome. Accreditation of these programs by the National Accreditation Commission is an opportunity to improve the trainee's research competences.

AIM

To analyze in the RTP curricula, the explicit intention to carry out clinical research and its correlation with the scientific productivity of professors and residents.

MATERIAL AND METHODS

Fifty six training study programs corresponding to six primary specialties and six derived specialties, offered by seven universities holding accreditation tenure for RTP from the Chilean Association of Medicine Faculties (ASOFAMECH) up to 2005, were analyzed. The analysis included each academic program, courses and/or rotations and professors and residents' productivity, measured as publications accredited in the Institute for Scientific Information (ISI), between 1999 and 2007.

RESULTS

RTP are based on a tutorial educational model, where the close relationship between professors and residents is essential for the expected final outcome. Simultaneously, the programs' curricula revealed a high intentionality towards clinical research. However, professors' publications of ISI indexed articles showed a low and irregular scientific productivity.

CONCLUSIONS

The gap between the declared training in clinical research and the effective ISI productivity is an awareness call with respect to the contribution that RTP could provide to accreditation, to professors and residents, and in general to health improvement in the country.

Activation of kinin B receptor triggers differentiation of cultured human keratinocytes

BACKGROUND

Keratinocyte life span is modulated by receptors that control proliferation and differentiation, key processes during cutaneous tissue repair. The kinin B(1) receptor (B(1)R) has been reported in normal and pathological human skin, but so far there is no information about its role in keratinocyte biology.

OBJECTIVES

To determine the consequence of kinin B(1)R stimulation on tyrosine phosphorylation, a key signalling mechanism involved in keratinocyte proliferation and differentiation.

METHODS

Subconfluent primary cultures of human keratinocytes were used to investigate tyrosine phosphorylation, epidermal growth factor receptor (EGFR) transactivation, cell proliferation and keratinocyte differentiation. Cell proliferation was assessed by measuring bromodeoxyuridine incorporation whereas assessment of cell differentiation was based on the expression of filaggrin, cytokeratin 10 (CK10) and involucrin.

RESULTS

The major proteins phosphorylated, after B(1)R stimulation, were of molecular mass 170, 125, 89 and 70 kDa. The 170- and 125-kDa proteins were identified as EGFR and p125(FAK), respectively. Phosphorylation was greatly reduced by GF109203X and by overexposure of keratinocytes to phorbol 12-myristate 13-acetate, indicating the participation of protein kinase C. B(1)R stimulation did not increase [Ca(2+)]i, but triggered EGFR transactivation, an event that involved phosphorylation of Tyr(845), Tyr(992) and Tyr(1068) of EGFR. B(1)R stimulation did not elicit keratinocyte proliferation, but triggered cell differentiation, visualized as an increase of filaggrin, CK10 and involucrin. Blockade of EGFR tyrosine kinase by AG1478, before B(1)R stimulation, produced an additional increase in filaggrin expression.

CONCLUSIONS

The kinin B(1)R may contribute to keratinocyte differentiation and migration by triggering specific tyrosine signalling pathways or by interacting with the ErbB receptor family.

Kinin B2 Receptor-Coupled Signal Transduction in Human Cultured Keratinocytes

Kinins are key pro-inflammatory peptides that exhibit mitogenic effects in tissue-specific cellular systems. Since the life span of the keratinocyte is regulated by receptors that control proliferation and differentiation, and since both processes are affected during wound healing, we have examined the consequence of kinin B2 receptors (B2R) activation in cultured human keratinocytes. Stimulation of keratinocytes by Lys-bradykinin (LBK) induced a rapid and sustained phosphorylation of 42/44 mitogen-activated protein kinase (MAPK) that translocated to the nucleus, and decreased only after 120 min of stimulation. Kinin B1 and B2 receptor (B1R and B2R) antagonists showed that phosphorylation was mainly because of B2R activation. The GF109203X inhibitor almost completely abolished the effect of LBK, suggesting the involvement of protein kinase C in the signal cascade. MAPK phosphorylation was partially dependent on epidermal growth factor receptor transactivation as assessed by the selective inhibitor, AG1478. LBK stimulation did not result in cell proliferation, but produced a rapid c-Fos expression, nuclear translocation of nuclear factor-kappaB, and a moderated (pro)filaggrin synthesis, indicating that it may modulate cell differentiation. Our results support the view that kinins may affect the life span of human keratinocytes and highlight the importance that kinin peptides may have in the pathogenesis and/or progression of skin diseases.

Evidence for modulation of human epidermal differentiation and remodelling by CD40

BACKGROUND

It is widely accepted that CD40 plays a critical role in the regulation of immune response. However, the significance of CD40 expression on normal human keratinocytes is only partially known.

OBJECTIVES

To perform a morphological re-examination of the role of CD40 on the differentiation of human keratinocytes and remodelling of the epidermis.

METHODS

Keratinocytes were grown on fibroblasts transfected with the CD40 ligand (CD40L) to investigate the formation of epidermal sheets in culture under the influence of the CD40L. Control experiments were carried out using the same cells but transfected with CD32. Further, three specific anti-CD40 monoclonal antibodies were used as soluble agonists to analyse the effect of CD40 ligation on keratinocyte differentiation.

RESULTS

Epidermal sheets developing from keratinocytes cocultured with fibroblasts transfected with CD40L but not with CD32 showed an up to 50% reduction in thickness compared with control sheets. This change depended mostly on cellular flattening and a decrease in the number of cell layers, and was coincident with a transient decrease in cell surface CD40 immunoreactivity. On the other hand, normal epidermis, and freshly isolated and cultured keratinocytes revealed a predominant CD40+/Ki-67- phenotype that was demonstrated by double immunocytochemistry. Consistent with these observations, keratinocytes primed with interferon-gamma responded to the three soluble agonists, but not to control IgG1, producing immunoreactive (pro)filaggrin and displaying morphological changes in shape and size equivalent to those seen in differentiated cells.

CONCLUSIONS

As a whole, our findings provide evidence that CD40+ keratinocytes represent a poorly differentiated population, not actively engaged in the cell cycle, which under specific stimulation is committed towards terminal differentiation.

Topotecan in the treatment of acquired immunodeficiency syndrome-related progressive multifocal leukoencephalopathy

Progressive multifocal leukoencephalopathy (PML) affects about 1 in 20 individuals with the acquired immunodeficiency syndrome (AIDS) and has been associated with poor survival. This report describes the results of a phase II clinical trial using the drug topotecan, a semisynthetic analogue of camptothecan, administered to a cohort of subjects with AIDS-related PML. Data were evaluated on 11 of 12 subjects enrolled in the study. Three responded to therapy. Additionally, one patient was treated off-protocol and showed a response to treatment. Progression occurred after the first course; however, a partial response was noted after five courses. One study patient died from accidental overdose of topotecan. Overall, responders had higher pretreatment Karnofsky and lower Kurtzke expanded disability status scale scores than nonresponders. The most frequent toxicities were hematologic (anemia, neutropenia, and thrombocytopenia). Five patients had dose delays; all delays were due to hematologic adverse events. This study demonstrates that topotecan treatment may be associated with decreased lesion size and prolonged survival from the infection. Because of the small number of subjects in the study, further studies are required to evaluate the efficacy of topotecan in treating this disease.

Evolutionary divergence of the reptilian and the mammalian brains: considerations on connectivity and development

The isocortex is a distinctive feature of the mammalian brain, with no clear counterpart in other amniotes. There have been long controversies regarding possible homologues of this structure in reptiles and birds. The brains of the latter are characterized by the presence of a structure termed dorsal ventricular ridge (DVR), which receives ascending auditory and visual projections, and has been postulated to be homologous to parts of the mammalian isocortex (i.e., the auditory and the extrastriate visual cortices). Dissenting views, now supported by molecular evidence, claim that the DVR originates from a region termed ventral pallium, while the isocortex may arise mostly from the dorsal pallium (in mammals, the ventral pallium relates to the claustroamygdaloid complex). Although it is possible that in mammals the embryonic ventral pallium contributes cells to the developing isocortex, there is no evidence yet supporting this alternative. The possibility is raised that the expansion of the cerebral cortex in the origin of mammals was product of a generalized dorsalizing influence in pallial development, at the expense of growth in ventral pallial regions. Importantly, the evidence suggests that organization of sensory projections is significantly different between mammals and sauropsids. In reptiles and birds, some sensory pathways project to the ventral pallium and others project to the dorsal pallium, while in mammals sensory projections end mainly in the dorsal pallium. We suggest a scenario for the origin of the mammalian isocortex which relies on the development of associative circuits between the olfactory, the dorsal and the hippocampal cortices in the earliest mammals.

parachute/n-cadherinis required for morphogenesis and maintained integrity of the zebrafish neural tube

N-cadherin (Ncad) is a classical cadherin that is implicated in several aspects of vertebrate embryonic development, including somitogenesis, heart morphogenesis, neural tube formation and establishment of left-right asymmetry. However, genetic in vivo analyses of its role during neural development have been rather limited. We report the isolation and characterization of the zebrafish parachute (pac) mutations. By mapping and candidate gene analysis, we demonstrate that pac corresponds to a zebrafish n-cadherin (ncad) homolog. Three mutant alleles were sequenced and each is likely to encode a non-functional Ncad protein. All result in a similar neural tube phenotype that is most prominent in the midbrain, hindbrain and the posterior spinal cord. Neuroectodermal cell adhesion is altered, and convergent cell movements during neurulation are severely compromised. In addition, many neurons become progressively displaced along the dorsoventral and the anteroposterior axes. At the cellular level, loss of Ncad affects β-catenin stabilization/localization and causes mispositioned and increased mitoses in the dorsal midbrain and hindbrain, a phenotype later correlated with enhanced apoptosis and the appearance of ectopic neurons in these areas. Our results thus highlight novel and crucial in vivo roles for Ncad in the control of cell convergence, maintenance of neuronal positioning and dorsal cell proliferation during vertebrate neural tube development.

Aging and neuro-AIDS conditions and the changing spectrum of HIV-1-associated morbidity and mortality

Older individuals (>50 years of age) now comprise over 11% of patients with AIDS in the United States. This percentage is expected to continue to grow, due both to the improved longevity of patients prescribed highly active antiretroviral therapy (HAART) and to new infections among older individuals. This review focuses on the neuropsychiatric and neurological conditions that are most likely to be affected by advancing age-HIV-1-associated cognitive-motor disorder, peripheral neuropathy, progressive multifocal leukoencephalopathy, primary CNS lymphoma, and risk for cerebrovascular accident. Age associations with incidence of these disorders and with treatment foci are specified. Implications for future changes in management are discussed.

Behavior of the pulmonary autograft in systemic circulation after the Ross procedure

OBJECTIVE

The purpose of this study was to evaluate performance in systemic circulation following pulmonary autograft aortic root replacement by means of serial postoperative echocardiographic studies.

METHODS

From November 1997 to November 1999, 30 patients (21 males, 9 females) with a mean age of 29.97 +/- 12.97 years (age range 6-54 years) underwent pulmonary autograft aortic root replacement. Seven of these patients (23.33%) were less than 15 years old. Postoperative echocardiographic measurements of the neo-aortic root were performed within three months of operation, at six months, one year, and annually thereafter. Analysis of this study includes 22 patients with at least three months of follow-up.

RESULTS

Operative mortality was 0%. Compared with preoperative values, the mean autograft annulus diameter exhibited an increase of 8.44% in the first month (1.44 +/- 0.22 cm/m2 vs. 1.55 +/- 0.21 cm/m2, p = 0.0101). An additional aortic annular dilation of 11.33% from baseline preoperative values was observed within the first year (1.41 +/- 0.15 cm/m2 preoperatively vs. 1.57 +/- 0.22 cm/m2, p = 0.0449). After the immediate postoperative period, the pulmonary autograft seemed to adapt to systemic circulation, and there were no differences in aortic annular size between 1-3 months after surgery and the 18-21 month follow-up period (1.60 +/- 0.18 cm/m2 vs. 1.60 +/- 0.27 cm/m2, n = 10). Diameter increase was not associated with the presence of aortic regurgitation. Mean neo-aortic maximal gradient was 7.85 +/- 5.59 mm Hg (3-29 mm Hg). There was a significant decrease in left ventricular size three months after surgery (50.71 +/- 10.20 mm preoperatively vs. 44.98 +/- 7.29 mm, p = 0.0491 in aortic stenosis patients and 68.50 +/- 8.39 mm vs. 59.04 +/- 9.21 mm, p = 0.0017 in aortic insufficiency patients).

CONCLUSIONS

Pulmonary autograft annulus increases up to the first year after the Ross procedure but does not appear to progress beyond that time. The pulmonary autograft allows optimal hemodynamic performance without causing substantial aortic regurgitation, thereby permitting normalization of left ventricular dimensions and improvement of left ventricular function early in the postoperative period.

[Clinical Characteristics and Evolution of Recurrent Infectious Endocarditis in non Drug Addicts]

INTRODUCTION AND OBJECTIVES

Recurrence of infection is observed in a high proportion of patients who have had infective endocarditis in the past. The aim of our study was to evaluate the possible differences between the first and the recurrent episodes of endocarditis, as well as to assess the outcome and prognosis of patients with recurrent endocarditis.

PATIENTS AND METHOD

We reviewed a series of 13 episodes of recurrent endocarditis from among 196 cases of infective endocarditis involving non-drug-addict patients in two hospitals from 1987 to 2000.

RESULTS

There were no differences between recurrent and first episodes of endocarditis according to age, sex, heart valve involved or causal microorganisms. Prosthetic valve endocarditis was more common in patients with recurrent endocarditis (86% versus 27%; p < 0.001). Although there were no differences in the rate of complications or early surgery, overall mortality was significantly higher in patients with recurrent endocarditis (53% versus 27%: p < 0.05). When early and late mortality were analysed separately, the differences did not achieve significance.

CONCLUSIONS

Recurrent endocarditis was frequent in our series (7% of all cases). The features were similar to those of the first episode except for a higher rate of prosthetic valve endocarditis and a higher overall mortality.

[Aortic valve replacement with pulmonary autograft (the Ross procedure) in adult and pediatric patients]

Aortic valve replacement with pulmonary autograft was first performed by Donald Ross in 1967. Initially, the procedure was not widely accepted, by Cardiologists and Cardiac surgeons fundamentally due to its complexity and demanding surgical technique, and because innumerous series two cardiac valves were at risk. The results published in the last 10-15 years established the pulmonary autograft as one of the best methods of aortic valve replacement, especially in pediatric patients and young adults. In the present article, we reviewed present indications and contraindications, and our clinical experience with 26 patients (pediatrics and adults). Analysis of the first 22 the patients with a minimum of 6 months of follow-up (180-620 days) was performed. Follow-up is complete (100%). Mean age was 31.4 +/- 12.6 years. Five patients were pediatrics (<= 14 years). Three patients (11%) with previous percutaneous procedures and 4 patients (14%) with previous surgical procedures. There was no early or late mortality. In the last follow-up, 19 of 22 (86.36%) had no autograft insufficiency (>= grade 1), and in one patient it was moderate (grade 2). The 2 remaining patients developed severe autograft insufficiency (grade 4) and were reoperated on, with satisfactory postoperative outcome. Mean maximal gradient was 7.85 +/- 5 mmHg at 18 months (3-29). Patients with preoperative aortic stenosis showed a significant reduction in myocardial mass index (208.7 +/- 32 a 95.8 +/- 28.8 g/m2) at 18 months. In these patients, septal and posterior wall thickness decreased significantly, in the first month. Two pediatric patients have developed transpulmonar gradient > 50 mmHg. One of them underwent successful stent implantation. We have not observed significant homograft insufficiency in any of our patients. All our patients remain asymptomatic (functional class I) without medical treatment. We have not observed either thromboembolic or haemorrhagic episodes, nor endocarditis. No patient is receiving anticoagulants. Clinical and echocardiographic mid term results in pulmonary autograft and homograft in our series, are excellent after the Ross procedure.

Left ventricular remodeling after pulmonary autograft replacement of the aortic valve (Ross operation)

BACKGROUND AND AIM OF THE STUDY

Aortic valve replacement (AVR) with a pulmonary autograft is an alternative treatment for young patients with aortic valve disease. Superior hemodynamic performance of the pulmonary autograft, and impact on parameters of left ventricular function were analyzed.

METHODS

Thirty patients (21 males, nine females; mean age 29.97+/-12.29 years; range: 6-54 years) underwent a Ross procedure between November 1997 and November 1999. Seven patients (23%) were children (aged <15 years). In total, 22 patients were analyzed; each had at least three months follow up. Eleven patients had predominant aortic stenosis (AS), and 11 had aortic insufficiency (AI).

RESULTS

There were no operative deaths. Two patients developed severe insufficiency, and the autograft was replaced with a mechanical valve. Pre- and postoperative echocardiograms were reviewed. The mean neoaortic maximal gradient was 7.85+/-5.59 mmHg (range: 3-29 mmHg). AS patients showed reduced interventricular septal (IVS) thickness at one month (from 13.27+/-3.69 to 11.60+/-2.44 mm; p = 0.0165) and 18 months after surgery (p = 0.0104). Left ventricular posterior wall (LVPW) thickness was reduced from 12.04+/-3.75 to 9.48+/-2.47 mm (p = 0.0338) at one month and 18 months (p= 0.0128) after surgery. The left ventricular end-diastolic internal dimension (LVIDd) decreased from 50.71+/-10.20 to 44.98+/-7.29 mm (p = 0.0491) at one month after surgery. In AI patients, LVPW and IVS thicknesses showed no significant variation, and LVIDd was decreased at one month (from 68.50+/-8.39 to 59.04+/-9.21 mm; p = 0.0017) and 18 months (p = 0.0229) after surgery. Left ventricular end-systolic internal dimension (LVIDs) decreased from 44.06+/-6.39 to 39.03+/-7.99 mm (p = 0.0081) at three months after surgery. Left ventricular mass index (LVMI) in the AS group decreased from 179.01+/-62.26 to 115.74+/-37.62 g/m2 (p = 0.0021) at one month after surgery, and at 18 months was normal, with a decrease from 208.77+/-32.89 to 95.89+/-28.82 g/m2 (p= 0.0003) (n = 5). In the AI group, LVMI decreased from 186.25+/-85.21 to 140.58+/-62.02 g/m2 (p = 0.0011) at one month after surgery, and at 18 months from 217.70+/-98.02 to 146.73+/-84.55 g/m2 (p= 0.0131) (n = 5).

CONCLUSION

The pulmonary autograft procedure can be used safely to replace the aortic valve, and allows optimal hemodynamic performance, with no significant aortic regurgitation. The Ross procedure results in normalization of left ventricular dimensions and improvement of left ventricular function early in the postoperative period.

Anticoagulation and microembolus detection in a case of internal carotid artery dissection

BACKGROUND

Microembolic signals (MES) have been demonstrated by transcranial Doppler (TCD) in cases of internal carotid artery dissection. The influence of treatment on MES in arterial dissection is uncertain. The authors here present a case of internal carotid artery dissection in which we detected a reduction of MES after the initiation of intravenous heparin.

METHODS

A 37-year-old woman developed a right temporal headache 10 days prior to admission. This was followed by episodes of left arm numbness and weakness. Magnetic resonance imaging (MRI) showed a right frontal and deep subcortical ischemic infarct. Catheter angiography confirmed a right internal carotid artery dissection with intracranial extension. She was then monitored with TCD for MES before and after intravenous heparin was started.

RESULTS

The first TCD, performed 12 days after symptom onset, showed 39 MES during 60 minutes of insonation of the right middle cerebral artery. Treatment with intravenous heparin resulted in a decline in MES by 50% after 96 hours. This decline continued and no further MES were detected after 11 days of anticoagulation.

CONCLUSION

The authors were able to demonstrate a decline of MES with heparin anticoagulation in a case of internal carotid artery dissection.

Horseradish peroxidase binding to intestinal brush-border membranes of Cyprinus carpio. Identification of a putative receptor

Morphologic studies have shown that the classic endocytosis tracer horseradish peroxidase (HRP) is actively internalized by vesicular transport in the carp intestine, suggesting the existence of specific binding sites in the apical membrane of enterocytes. The aim of the present study was to develop an in vitro binding assay using isolated carp intestinal brush-border membranes (BBM) to demonstrate and characterize these specific HRP binding sites. The results obtained show that HRP binding to BBM exhibits a saturable mode and high affinity (K(d) = 22 nM). In addition, HRP binding sites are highly enriched in BBM compared to basolateral membranes. On the other hand, HRP interaction with these sites is apparently of an ionic character because binding increased concomitantly with decreasing NaCl concentrations in the assay, reaching a maximum in the absence of NaCl. Other proteins that are also internalized in carp intestine did not significantly inhibit HRP binding to BBM. A lectin-type of interaction was discarded because neither manan nor ovoalbumin inhibited HRP binding. Proteinase K treatment of BBM reduced HRP binding by 70%, suggesting a proteic nature for this binding site. Finally, ligand blotting assays showed that HRP binds specifically to a 15.3-kDa protein. Taken together, these results are consistent with the existence of a functional receptor for HRP in carp intestinal mucosa that could mediate its internalization.

Intramucosal gastric pH during liver transplantation

Intramucosal gastric pH (pHi) was measured during liver transplantation in a 3-year-old girl. The basal value was below that reported as normal for paediatric patients under stable normal ventilatory and haemodynamic conditions. Additional reductions of the pHi were observed during the hepatectomy and anhepatic phase, in the absence of haemodynamic or ventilatory alterations. The reperfusion phase was characterized by a progressive return toward normal values. Because we did not measure oxygen delivery and consumption, we cannot determine whether the reduction of the pHi was due to insufficient oxygen delivery or a result of the vascular anatomical alterations due to the surgical procedure.

Long term outcome of infective endocarditis in patients who were not drug addicts: a 10 year study

OBJECTIVE

To determine the clinical features and long term prognosis of infective endocarditis in patients who were not drug addicts.

DESIGN

Prospective case series.

SETTING

A university hospital that is both a referral and a primary care centre.

PATIENTS

138 consecutive cases of infective endocarditis diagnosed and treated from January 1987 to March 1997.

RESULTS

Mean patient age was 44 (20) years old. 95 patients (69%) had native valve endocarditis and 43 (31%) had prosthetic valve endocarditis. Staphylococci were the causal microorganisms in 34% of cases and streptococci in 33%. Severe complications occurred in 83% of patients and 51% of patients underwent surgery during the active phase (22% was emergency surgery). Inpatient mortality was 21%. During a follow up of 56 (44) months, 10 patients (9%) needed late cardiac surgery and seven (5% of the whole series) died. Overall 10 year survival was 71%. There were no significant differences in survival depending on the type of treatment received during the hospital stay (medical or combined medical-surgical).

CONCLUSIONS

A high early surgery rate is related to good long term results and does not increase in-hospital mortality. Medical treatment, however, also offers favourable long term results in cases of responsive infective endocarditis where poor prognostic factors are absent.

CD40 ligation alters the cell cycle of differentiating keratinocytes

CD40 is expressed in normal human keratinocytes, especially in the basal cell layer. We have recently reported that CD40 ligation strongly inhibits keratinocyte proliferation and induces their differentiation. In this study, the CD40 pathway that prevents keratinocyte growth was investigated. We first reported that interferon-gamma treatment potentiated the CD40-mediated inhibition of keratinocyte proliferation. CD40-CD40 ligand interactions, in the presence or absence of interferon-gamma, neither enhanced spontaneous keratinocyte apoptosis, nor did it enhance apoptosis induced by various agents. More importantly, we showed that CD40 signaling altered the keratinocyte cell cycle, as demonstrated by a decreasing number of cells in the G1 and S phases and an accumulation in G2/M phase of the cell cycle. Furthermore, western blot analysis of cell cycle regulatory proteins, showed a decrease in cyclin A and E expression in CD40-activated keratinocytes. Collectively, these results indicate that CD40 ligation inhibits keratinocyte renewal by a mechanism independent of cell apoptosis and that modulation of the keratinocyte cell cycle is an additional outcome of CD40 signaling.

[Aortic valve replacement with a pulmonary autograft (the Ross operation) in adult and pediatric patients. A preliminary study]

INTRODUCTION AND OBJECTIVES

Aortic valve replacement with the patients own pulmonary autograft (the Ross procedure) is by now, the best surgical method for the replacement of the diseased aortic valve in certain groups of patients, this is particularly true for young adults and children or neonates with complex left ventricular outflow tract obstructions. The procedure was described by Donald Ross in 1967, and many years have passed. So in view of the accumulated experience the indications have extended to a wide group of patients which include children, neonates and young adults with formal contraindications for anticoagulation. In this publication we present our experience and our preliminary results in a group of fifteen patients which include adult and pediatric.

MATERIAL AND METHODS

In six patients the etiology of lesion was congenital and in the remainder nine the valve had an acquired lesion. Two patients had an open heart procedure before this operation both of them to relieve an obstruction to the left ventricular outflow tract. In this group of patients the Ross procedure was carried out inserting the pulmonary autograft in the aortic position as a total root which was always reconstructed with cryopreserved pulmonary homograft, the mean homograft diameter was 26.1 +/- 4 mm (19-35).

RESULTS

In all patients a transesophageal echocardiogram was performed in the operating room and postoperative, 1 or 2 months later. Only in one patient a mild aortic regurgitation was detected, no significant transaortic or transpulmonary gradients were detected postoperative. One patient was reoperated for bleeding in the postoperative course, there was no hospital mortality in our group and all the patients had an uneventful postoperative period. In the short term follow-up (41-155 days). All the patients are free of anticoagulant therapy, all them are in New York Heart Association Functional Class I.

CONCLUSIONS

The patients presented in this publication which include adult and pediatric, are the first group of patients operated in our country with some excellent preliminary results. We hope that this procedure will become popular and that other surgical groups will adopt it as another surgical tool to replace a diseased aortic valve.

Bezafibrate and lovastatin decrease the oxidizability of low-density lipoproteins in heart transplant recipients with hyperlidemia

BACKGROUND

Oxidized low-density lipoprotein plays an important role in the development of atherosclerosis. We evaluated the effect of two lipid-lowering drugs, bezafibrate and lovastatin, on the susceptibility of low-density lipoproteins for oxidation in vitro in 21 heart transplant recipients with hyperlipidemia.

METHODS

Patients were given the same diet for 3 months, and after that they were randomized to lovastatin or bezafibrate for a period of 8 weeks and then crossed over to an additional 8 weeks of either bezafibrate or lovastatin. Baseline parameters were also compared with those of a control group of healthy subjects and after both periods of pharmacologic treatment.

RESULTS

The low-density lipoproteins of transplant recipients presents a shorter lag time than in control subjects (64+/-3 vs 80+/-4 minutes, respectively). This parameter increases after both bezafibrate and lovastatin treatment (83+/-5 and 80+/-4 minutes, respectively). Moreover, we did observe a negative correlation between insulinemia and the lag time of oxidation after bezafibrate treatment (r = -0.5014, P < .021) and between the polyunsaturated fatty acids/monounsaturated fatty acids ratio in low-density lipoprotein cholesterol esters and lag time after lovastatin treatment (r = -0.4631, P < .04).

CONCLUSIONS

Bezafibrate and lovastatin decrease the oxidizability of low-density lipoproteins in heart transplant recipients with hyperlipemia.

[Influence of genetic variation at apoprotein A-1 gene promoter region on plasma lipid levels in heart transplantation patients]

BACKGROUND

To study if the presence of the G/A polymorphism at the apo A-I gene promoter region could determine the lipid profile in patients with hyperlipidemia after heart transplantation, or if it is related with the type of heart disease that determined the transplantation.

PATIENTS AND METHODS

This study included 31 patients with hyperlipidemia after heart transplantation. Anthropometric parameters, basic analytic and lipid study were measured in these subjects. Identification of the G/A mutation in the promoter region of the apo A-I gene was performed.

RESULTS

22 patients had the G/G genotype and 9 the G/A. 14 were transplanted by coronary heart disease and 17 by non ischemic heart disease. Patients with the A allele had higher cHDL (63 [SD 15] vs 53 [10]; p = 0.034) and apo A-I plasma levels (156 [34] vs 132 [24]; p = 0.040) than G/G subjects. The A allele was present in the 18% of the patients transplanted by ischemic heart disease and in the 43% of the transplanted by another etiology (p = 0.073).

CONCLUSIONS

The presence of the G/A genotype in the promoter region of the apo A-I gene determines higher plasma levels of cHDL in patients with hyperlipidemia after heart transplantation.

Effects of ultraviolet B radiation on human Langerhans cells: functional alteration of CD86 upregulation and induction of apoptotic cell death

We have recently reported that in vitro low dose of ultraviolet B radiation (UVB, 100-200 J per m2) directly impaired the antigen-presenting function of human Langerhans cells. In this study, we analyzed the effect of UVB irradiation on the Langerhans cells expression of several accessory molecules, namely CD54, CD80, and CD86. Langerhans cells phenotype was determined either immediately after UVB exposure (100 J per m2) or after a 2 d culture. No modification in cell surface antigen levels was observed immediately after irradiation. Prior UVB exposure did not modify the levels of CD80 at the Langerhans cells surface after a 2 d culture. In contrast, CD54 and, above all, CD86 expression were significantly decreased. Addition of exogenous anti-CD28 monoclonal antibodies partly restored the allostimulatory property of irradiated Langerhans cells in mixed epidermal cell-lymphocyte reaction, demonstrating that impairment of CD86 upregulation contributes to the UVB-induced immunosuppressive effect. Furthermore, we found that UVB irradiation at 200 J per m2 significantly reduced the number of viable Langerhans cells after 2 d of culture. UVB-induced cytotoxicity was due to apoptotic cell death, as demonstrated by typical morphologic alterations and by DNA fragmentation yielding a classical ladder pattern on gel electrophoresis. Interestingly, interaction of Langerhans cells with CD40-ligand transfected L cells improved the viability of irradiated Langerhans cells, counteracted the inhibition of CD86 expression, and efficiently reduced the number of apoptotic cells after a 2 d culture. Collectively, these results demonstrate that in vitro UVB exposure affects Langerhans cells via at least two distinct pathways: (i) decreased CD86 costimulatory molecule upregulation; and (ii) induction of Langerhans cells apoptosis, a phenomenon partly prevented by CD40 triggering.