FGF2/EGF contributes to brain neuroepithelial precursor proliferation and neurogenesis in rat embryos: the involvement of embryonic cerebrospinal fluid.

BACKGROUND: At the earliest stages of brain development, the neuroepithelium works as an interdependent functional entity together with cerebrospinal fluid, which plays a key regulatory role in neuroepithelial cell survival, replication and neurogenesis; however, the underlying mechanism remains unknown in mammals. RESULTS: We show the presence of fibroblast growth factor 2 (FGF2) and epidermal growth factor (EGF), in 13.5-day rat embryo cerebrospinal fluid (eCSF). Immunohistochemical detection of FGF2 expression localized this factor inside neuroepithelial precursors close to the neuroepithelial-CSF interface, suggesting that FGF2 from eCSF could originate in the neuroepithelium by apical secretion. The colocalization of FGFR1 and FGF2 in some neuroepithelial cells close to the ventricular surface suggests they are target cells for eCSF FGF2. Brain neuroepithelium EGF expression was negative. By using a neuroepithelial organotypic culture, we demonstrate that FGF2 and EGF from eCSF plays a specific role in triggering the self-renewal and are involved in neurogenetic induction of mesencephalic neuroepithelial precursor cells during rat development. CONCLUSIONS: We propose eCSF as an intercommunication medium for neuroepithelial precursor behavior control during early rat brain development, and the neuroepithelial regulation of FGF2 and EGF presence in eCSF, as a regulative mechanism controlling precursor proliferation and neurogenesis.

[Patient identification errors and biological samples in the analytical process: Is it possible to improve patient safety?]. / Errores en la identificación del paciente y en muestras biológicas en el proceso analítico: ¿es posible la mejora de la seguridad de los pacientes?

BACKGROUND: Patient identification errors and biological samples are one of the problems with the highest risk factor in causing an adverse event in the patient. OBJECTIVE: To detect and analyse the causes of patient identification errors in analytical requests (PIEAR) from emergency departments, and to develop improvement strategies. MATERIAL AND METHODS: A process and protocol was designed, to be followed by all professionals involved in the requesting and performing of laboratory tests. Evaluation and monitoring indicators of PIEAR were determined, before and after the implementation of these improvement measures (years 2010-2014). RESULTS: A total of 316 PIEAR were detected in a total of 483,254 emergency service requests during the study period, representing a mean of 6.80/10,000 requests. Patient identification failure was the most frequent in all the 6-monthly periods assessed, with a significant difference (P<.0001). CONCLUSIONS: The improvement strategies applied showed to be effective in detecting PIEAR, as well as the prevention of such errors. However, we must continue working with this strategy, promoting a culture of safety for all the professionals involved, and trying to achieve the goal that 100% of the analytical and samples are properly identified.

Ambulatory surgery in orthopedics: experience of over 10,000 patients.

PURPOSE: The concept of day surgery is becoming an increasingly important part of elective surgery worldwide. Relentless pressure to cut costs may constrain clinical judgment regarding the most appropriate location for a patient's surgical care. The aim of this study was to determine clinical and quality indicators relating to our experience in orthopedic day durgery, mainly in relation to unplanned overnight admission and readmission rates. Additionally, we focused on describing the main characteristics of the patients that experienced complications, and compared the patient satisfaction rates following ambulatory and non-ambulatory procedures. METHODS: We evaluated 10,032 patients who underwent surgical orthopedic procedures according to the protocols of our Ambulatory Surgery Unit. All complications that occurred were noted. A quality-of-life assessment (SF-36 test) was carried out both pre- and postoperatively. Ambulatory substitution rates and quality indicators for orthopedic procedures were also determined. RESULTS: The major complication rate was minimal, with no mortal cases, and there was a high rate of ambulatory substitution for the procedures studied. Outcomes of the SF-36 questionnaire showed significant improvement postoperatively. An unplanned overnight admission rate of 0.14 % was achieved. CONCLUSIONS: Our institution has shown that it is possible to provide good-quality ambulatory orthopedic surgery. There still appears to be the potential to increase the proportion of these procedures. Surgeons and anesthesiologists must strongly adhere to strict patient selection criteria for ambulatory orthopedic surgery in order to reduce complications in the immediate postoperative term.

[New strategies to improve accessibility to laboratory tests in cancer patients]. / Nuevas estrategias de mejora en la accesibilidad a las pruebas de laboratorio de los pacientes en oncología.

OBJECTIVE: To develop models to improve accessibility of performing laboratory tests on chronic oncology patients, as well as a more flexible choice of sample collection in both primary and specialized care. MATERIAL AND METHODS: Circuit analysis of cancer patients. Patient survey to study access to laboratory tests. High Resolution Consultation Development Model (MCAR) and Patient Access Analytical Model (MAAP). RESULTS: The percentage of cancer patients on treatment has increased by 8.76% in the past two years. There was a 32% increased in the use of the MAAP model in the two years of its implementation, and has been the choice of 74% due to greater accessibility, with 8% of the patients having used both models to suit their needs. CONCLUSIONS: The implementation of optimized and preferred care systems has shown that both models improve accessibility and flexibility of the diagnostic testing laboratory in the patients studied.

Embryonic cerebrospinal fluid activates neurogenesis of neural precursors within the subventricular zone of the adult mouse brain.

INTRODUCTION: There is a nondeveloped neurogenic potential in the adult mammalian brain, which could be the basis for neuroregenerative strategies. Many research efforts have been made to understand the control mechanisms which regulate the transition from a neural precursor to a neuron in the adult brain. Embryonic cerebrospinal fluid (CSF) is a complex fluid which has been shown to play a key role in neural precursor behavior during development, working as a powerful neurogenic inductor. We tested if the neurogenic properties of embryonic CSF are able to increase the neurogenic activity of neuronal precursors from the subventricular zone (SVZ) in the brains of adult mice. RESULTS: Our results show that mouse embryonic CSF significantly increases the neurogenic activity in precursor cells from adult brain SVZ. This intense neurogenic effect was specific for embryonic CSF and was not induced by adult CSF. CONCLUSIONS: Embryonic CSF is a powerful neurogenesis inductor in homologous neuronal precursors in the adult brain. This property of embryonic CSF could be a useful tool in neuroregeneration strategies.

Early embryonic brain development in rats requires the trophic influence of cerebrospinal fluid.

Cerebrospinal fluid has shown itself to be an essential brain component during development. This is particularly evident at the earliest stages of development where a lot of research, performed mainly in chick embryos, supports the evidence that cerebrospinal fluid is involved in different mechanisms controlling brain growth and morphogenesis, by exerting a trophic effect on neuroepithelial precursor cells (NPC) involved in controlling the behaviour of these cells. Despite it being known that cerebrospinal fluid in mammals is directly involved in corticogenesis at fetal stages, the influence of cerebrospinal fluid on the activity of NPC at the earliest stages of brain development has not been demonstrated. Here, using "in vitro" organotypic cultures of rat embryo brain neuroepithelium in order to expose NPC to or deprive them of cerebrospinal fluid, we show that the neuroepithelium needs the trophic influence of cerebrospinal fluid to undergo normal rates of cell survival, replication and neurogenesis, suggesting that NPC are not self-sufficient to induce their normal activity. This data shows that cerebrospinal fluid is an essential component in chick and rat early brain development, suggesting that its influence could be constant in higher vertebrates.

Chondroitin sulphate-mediated fusion of brain neural folds in rat embryos.

Previous studies have demonstrated that during neural fold fusion in different species, an apical extracellular material rich in glycoconjugates is involved. However, the composition and the biological role of this material remain undetermined. In this paper, we show that this extracellular matrix in rat increases notably prior to contact between the neural folds, suggesting the dynamic behaviour of the secretory process. Immunostaining has allowed us to demonstrate that this extracellular matrix contains chondroitin sulphate proteoglycan (CSPG), with a spatio-temporal distribution pattern, suggesting a direct relationship with the process of adhesion. The degree of CSPG involvement in cephalic neural fold fusion in rat embryos was determined by treatment with specific glycosidases.In vitro rat embryo culture and microinjection techniques were employed to carry out selective digestion, with chondroitinase AC, of the CSPG on the apical surface of the neural folds; this was done immediately prior to the bonding of the cephalic neural folds. In all the treated embryos, cephalic defects of neural fold fusion could be detected. These results show that CSPG plays an important role in the fusion of the cephalic neural folds in rat embryos, which implies that this proteoglycan could be involved in cellular recognition and adhesion.

Prenatal expression of interleukin 1beta and interleukin 6 in the rat pituitary gland.

It is known that interleukin 1beta (IL-1beta) and interleukin 6 (IL-6) are expressed post-natally in normal and tumoral cells in the anterior pituitary, and that they play a role in both the liberation of different hormones and in the growth, proliferation and tumor formation of the pituitary gland. However, their expression and role during embryonic and fetal development remain unknown. We have performed an immunocytochemistry study of prenatal expression and distribution of IL-1beta and IL-6 in isolated embryonic rat Rathke's pouch prior to birth, more specifically between 13.5 and 19.5 days p.c. Western-blot analysis carried out on 19.5-day p.c. embryos showed positive immunolabelling for IL-1beta and IL-6. These interleukins were initially expressed simultaneously in the rostral and ventral portions of Rathke's pouch in 15.5-day p.c. embryos, and this expression progressed caudodorsally in later developmental stages, extending to most of the hypophysis before birth. The number of cells expressing these interleukins increased throughout this period: 48.22% of anterior pituitary cells expressed IL-6 in 19.5-day embryos, whilst IL-1beta was positive in 39.8% of the cells. Moreover, we have demonstrated that some adenohypophyseal cells co-express both interleukins. Such findings represent the first step towards an understanding of the physiological role of these interleukins in anterior pituitary development.

Randomized prospective study of the evolution of renal function depending on the anticalcineurin used.

BACKGROUND: Renal failure is one of the primary medium- to long-term morbidities in heart transplant (HT) recipients. To a great extent, this renal deterioration is associated with calcineurin inhibitors, primarily cyclosporine A (CsA). It has been suggested that tacrolimus provides better renal function in these patients. We assessed the medium-term evolution of renal function depending on the calcineurin inhibitor used after HT. PATIENTS AND METHOD: We assessed 40 consecutive HT recipients over one year. Patients were randomized to receive CsA (n = 20) or tacrolimus (n = 20) in combination with mycophenolate mofetil (1 g/12 h) and deflazacort in decreasing dosages. We analyzed demographic variables before HT, creatinine values before and six months after HT and incidence of acute rejection. RESULTS: No demographic, clinical, or analytical differences were observed were between the two groups before HT. Repeated measures analysis of variance of creatinine values showed no significant differences between the two groups (P = .98). Furthermore, no differences were observed in either the incidence of rejection (P = .02) or rejection-free survival (P = .14). CONCLUSION: There seems to be no difference in efficacy profile and renal tolerability between CsA and tacrolimus therapy during the first months after HT.

Clinical variables associated with the presence of inflammatory infiltrates in patients with dilated cardiomyopathy undergoing heart transplantation.

INTRODUCTION: Idiopathic dilated cardiomyopathy (DCM) is, together with ischemic heart disease, the major cause of end-stage heart failure leading to heart transplantation. However, an unknown percentage of patients with this diagnosis has inflammatory foci found in the histopathological study of the explanted heart. This fact suggests an undetected process of acute myocarditis as the cause of cardiac dysfunction. OBJECTIVE: The objective of this study was to identify clinical and echocardiographic variables related to the presence of myocardial infiltrates, as a potential guide to determine which patients should undergo endomyocardial biopsy in DCM. MATERIALS AND METHODS: We retrospectively analyzed 161 patients who underwent heart transplantation with a diagnosis of DCM between 1987 and 2007. The presence of inflammatory infiltrates was considered significant when the histopathological study of tissue blocks from the left ventricle showed 1 or more foci per cm(2) of perivascular or interstitial mononuclear or polymorphonuclear cells, whether or not in the presence of cytolysis. RESULTS: Seventeen patients (11%) had these inflammatory histological findings; of them, 6 (35%) showed preponderance of eosinophils and 7 (41%) showed areas of cytolysis. The DCM group with inflammatory infiltrates showed significant differences in terms of younger age (45 +/- 15 vs 50 +/- 11 years; P < .01) and smaller ventricular diameters (P < .05). Male gender was more frequent in this group, and the patients had a poorer clinical status and greater dependence on inotropic drugs. CONCLUSIONS: Inflammatory infiltrates are frequently present in DCM explanted hearts. Although there are no relevant clinical variables to identify subclinical myocarditis, these patients are younger and have smaller ventricular diameters and poorer functional status at the time of transplantation.

Tolerance profile of the proliferation signal inhibitors everolimus and sirolimus in heart transplantation.

INTRODUCTION: The side effects of proliferation signal inhibitors (PSIs) have been characterized as a class. However, it would be convenient to assess them according to the molecule. OBJECTIVE: To assess prospectively the tolerance of PSIs among heart transplant (HT) patients. PATIENTS AND METHODS: We studied 56 HT patients who sequentially received PSIs to either withdraw (77%) or reduce the dosage of a calcineurin inhibitor; 42 received everolimus (EVE) and 14 sirolimus (SRL). We analyzed the demographic variables, side effects, and need to withdraw the drug during a median follow-up period of 365 days. RESULTS: No differences between groups were observed upon analysis of the clinical and demographic variables when the treatment was changed owing to renal dysfunction (67%) or tumor (32%). No difference between groups was observed over the follow-up period (P = .28). Infection was the most common side effect, 28.6%: EVE, 14.3% versus SRL, 71.4% (P < .0001). Edema occurred in 26.8% of patients: EVE, 14.3% versus SRL, 64.3% (P = .001); diarrhea in 5.4% of patients: EVE, 2.4% versus SRL, 14.3% (P = .15). Treatment was withdrawn in 23.2% of the patients due to intolerance: EVE, 11.9% versus SRL, 57.1% (P < .0001). EVE showed significantly better survival without edema or infections or used for drug withdrawal upon Kaplan-Meier analysis, (P = .01; P = .0005; P = .0097). Only SRL use was shown to be an independent predictor of side effects. CONCLUSION: Edema and infections are the main problems caused by PSIs. EVE may display a better tolerance profile than SRL.

Support program for heart transplant patients: initial experience.

INTRODUCTION: Trials of education and support in heart failure patients have shown an improvement in patient prognosis with favorable results in cost-benefit analysis. OBJECTIVES: To assess the impact of a telephone support program for heart transplant patients during the first year after transplantation. PATIENTS AND METHODS: We analyzed 30 consecutive heart transplant patients at our institution, who were randomized to either a standard care group or a group with the additional possibility of direct telephone contact with a cardiologist. We analyzed the time employed answering the calls, the reasons for consultation, and the number of hospital trips avoided. RESULTS: Among the total sample, 15 patients were assigned to the intervention program. Over 194 +/- 103 days, we received 28 calls. The mean call duration was 10.2 +/- 3.9 minutes, with 39.3% of the consultations concerning medication dosages 28.6% lifestyle issues, 25% infectious symptoms, and the remaining 7%, medication side effects. Medication readjustments were made in 33% of the calls; 10.7% of the calls, all for infectious symptoms, required direct medical consultation. CONCLUSION: Telephone support may be useful to improve therapeutic compliance, adjust the medications, and avoid treatment errors, as well as detect early complications during follow-up. In addition, it may avoid unnecessary medical visits.

Utility of oral valganciclovir for cytomegalovirus prophylaxis: does it improve treatment compliance?

INTRODUCTION: Cytomegalovirus (CMV) infection is a significant cause of morbidity and mortality among heart transplant (HT) patients. Various prophylactic and preemptive treatment regimens have been used for its prevention. We sought to assess the impact of oral valganciclovir on CMV prophylaxis in HT patients. PATIENTS AND METHODS: A retrospective analysis of 536 consecutive HT patients at our institution allowed selection of subjects eligible for prophylaxis based on CMV serology (donor positive/recipient negative). Treatment compliance, rates of preemptive therapy and treatment for CMV disease were assessed according to prophylactic drug use. If the indication was present, treatment was considered to have been performed. RESULTS: Among 536 patients, 9.8% (n = 53) were eligible for prophylaxis. Seventeen patients (33%) received valganciclovir, with a compliance rate of 94.1%. The remaining 68% received prophylaxis mainly with IV. ganciclovir (5 mg/kg) during their hospital stay followed by oral ganciclovir, with a compliance rate of 57.1% (P = .01). No differences were observed when we analyzed the need for preemptive therapy (0 vs 7%; P = .28) or for treatment of systemic or organ-specific infection (6.3 vs 0%; 6.3 vs 14%, respectively; P = .8). CONCLUSION: Oral valganciclovir facilitated treatment compliance in prophylaxis for CMV without being inferior to other prophylactic therapies.

Role of interleukin-1beta in the control of neuroepithelial proliferation and differentiation of the spinal cord during development.

Interleukin-1beta (IL-1beta) is an important trophic factor in the nervous system (NS). IL-1beta is ubiquitously expressed from very early stages during the development of the amphibian NS and its action has been demonstrated in vitro on survival, proliferation and differentiation in mammalian embryos. In this report, we show that IL-1beta is immunocytochemically expressed in embryonic spinal cord from early stages, both in rat (embryonic day 12) and in chicken (stage 17-HH), in neuroepithelial cells and nerve fibres, dorsal root ganglia, anterior and posterior roots of the spinal nerves, and in the fibres of these nerves. Our in vivo experiments on chick embryos, with microbeads impregnated with IL-1beta implanted laterally to the spinal cord at the level of the wing anlage, demonstrate that this cytokine produces a statistically significant increase in nuclear incorporation of BrdU at the dorsal level and a reduction of this at the ventral level, whereas local immunoblocking with anti-IL-1beta antibodies causes a dorsal reduction of BrdU incorporation and alters ventral differentiation. These data demonstrate that IL-1beta plays a part in controlling proliferation and early differentiation during the development of the spinal cord in chick embryos.

Do cardiovascular risk factors influence cardiac allograft vasculopathy?

BACKGROUND: Cardiac allograft vasculopathy (CAV) is the leading cause of heart transplant failure after the first year. The etiological factors involved are currently a controversial matter. Intravascular ultrasound (IVUS) is considered the diagnostic procedure of choice. We assessed the relationship of cardiovascular risk factors with CAV. MATERIALS: We analyzed prospectively 22 patients. We conducted a first study with coronary angiography and IVUS at 36 +/- 3 days and a second at 598 +/- 49 days. We performed an average of 5.6 clinical revisions per patient, assessing the effect of the classic cardiovascular risk factors, the cause of heart failure, and the age of the patient and donor. The statistics used were chi(2), Fisher exact test, and Student t test. RESULTS: CAV was found in 10 subjects (45.5%). Univariate analysis showed statistically significant differences in the assessment of the presence of diabetes and dyslipidemia posttransplantation, but not pretransplantation. Among the patients with CAV there was a higher percentage of diabetics (32.8% vs 12%, P < .01). The patients with CAV also had higher levels of total cholesterol (211 +/- 40 mg/dL vs 195 +/- 35 mg/dL, P = .02), triglycerides (172 +/- 108 mg/dL vs 136 +/- 66 mg/dL, P = .03), low-density lipoprotein (133 +/- 35 mg/dL vs 117 +/- 30 mg/dL, P = .01), and lower high-density lipoprotein levels (46 +/- 15 mg/dL vs 52 +/- 12 mg/dL, P = .03). CONCLUSIONS: Only the diabetes and dyslipidemia present in the posttransplantation period were associated with CAV, which highlights the fact that it is a condition that both shares and has different features with atherosclerosis and probably requires a different diagnostic-therapeutic approach.

FGF2 plays a key role in embryonic cerebrospinal fluid trophic properties over chick embryo neuroepithelial stem cells.

During early stages of brain development, neuroepithelial stem cells undergo intense proliferation as neurogenesis begins. Fibroblast growth factor 2 (FGF2) has been involved in the regulation of these processes, and although it has been suggested that they work in an autocrine-paracrine mode, there is no general agreement on this because the behavior of neuroepithelial cells is not self-sufficient in explants cultured in vitro. In this work, we show that during early stages of development in chick embryos there is another source of FGF2, besides that of the neuroepithelium, which affects the brain primordium, since the cerebrospinal fluid (E-CSF) contains several isoforms of this factor. We also demonstrate, both in vitro and in vivo, that the FGF2 from the E-CSF has an effect on the regulation of neuroepithelial cell behavior, including cell proliferation and neurogenesis. In order to clarify putative sources of FGF2 in embryonic tissues, we detected by in situ hybridization high levels of mRNA expression in notochord, mesonephros and hepatic primordia, and low levels in brain neuroectoderm, corroborated by semiquantitative PCR analysis. Furthermore, we show that the notochord segregates several FGF2 isoforms which modify the behavior of the neuroepithelial cells in vitro. In addition, we show that the FGF2 ligand is present in the embryonic serum; and, by means of labeled FGF2, we prove that this factor passes via the neuroepithelium from the embryonic serum to the E-CSF in vivo. Considering all these results, we propose that, in chick embryos, the behavior of brain neuroepithelial stem cells at the earliest stages of development is influenced by the action of the FGF2 contained within the E-CSF which could have an extraneural origin, thus suggesting a new and complementary way of regulating brain development.

Embryonic cerebrospinal fluid regulates neuroepithelial survival, proliferation, and neurogenesis in chick embryos.

Early in development, the behavior of neuroepithelial cells is controlled by several factors, which act in a developmentally regulated manner. Diffusible factors are secreted locally by the neuroepithelium itself, although other nearby structures may also be involved. Evidence suggests a physiological role for the cerebrospinal fluid in the development of the brain. Here, using organotypic cultures of chick embryo neuroepithelial explants from the mesencephalon, we show that the neuroepithelium in vitro is not able to self-induce cell survival, replication, and neurogenesis. We also show that the embryonic cerebrospinal fluid (E-CSF) promotes neuroepithelial stem cell survival and induces proliferation and neurogenesis in mesencephalic explants. These data strongly suggest that E-CSF is involved in the regulation of neuroepithelial cells behavior, supporting the hypothesis that this fluid plays a key role during the early development of the central nervous system.

Analysis of cerebro-spinal fluid protein composition in early developmental stages in chick embryos.

Foetal cerebro-spinal fluid (CSF) has a very high protein concentration when compared to adult CSF, and in many species five major protein fractions have been described. However, the protein concentration and composition in CSF during early developmental stages remains largely unknown. Our results show that in the earliest stages (18 to 30 H.H.) of chick development there is a progressive increase in CSF protein concentration until foetal values are attained. In addition, by performing electrophoretic separation and high-sensitivity silver staining, we were able to identify a total of 21 different protein fractions in the chick embryo CSF. In accordance with the developmental pattern of their concentration, these can be classified as follows: A: high-concentration fractions which corresponded with the ones described in foetal CSF by other authors; B: low-concentration fractions which remained stable throughout the period studied; C: low-concentration fractions which show changes during this period. The evolution and molecular weight of the latter group suggest the possibility of an important biological role. Our data demonstrate that all the CSF protein fractions are present in embryonic serum; this could mean that the specific transport mechanisms in neuroepithelial cells described in the foetal period evolve in very early stages of development. In conclusion, this paper offers an accurate study of the protein composition of chick embryonic CSF, which will help the understanding of the influences on neuroepithelial stem cells during development and, as a result, the appropriate conditions for the in vitro study of embryonic/foetal nervous tissue cells.

Personalidad múltiple: un caso raro en la práctica forense / Multiple personality: a rare case in forensic practise

Se describe un caso de trastorno de identidad disociativo (personalidad múltiple) que motivó estudio forense por tener relación directa con el homicidio de un recién nacido. La personalidad múltiple es un trastorno poco frecuente, y excepcional en el ámbito forense, consistente en la coexistencia en un individuo de dos o más personalidades independientes. El presente trabajo trata de llamar la atención sobre su existencia y su forma de presentarse (AU)

TGF-beta(3)-induced chondroitin sulphate proteoglycan mediates palatal shelf adhesion.

In mammals, the adhesion and fusion of the palatal shelves are essential mechanisms in the development of the secondary palate. Failure of any of these processes leads to the formation of cleft palate. The mechanisms underlying palatal shelf adhesion are poorly understood, although the presence of filopodia on the apical surfaces of the superficial medial edge epithelial (MEE) cells seems to play an important role in the adhesion of the opposing MEE. We demonstrate here the appearance of chondroitin sulphate proteoglycan (CSPG) on the apical surface of MEE cells only immediately prior to contact between the palatal shelves. This apical CSPG has a functional role in palatal shelf adhesion, as either the alteration of CSPG synthesis by beta-D-Xyloside or its specific digestion by chondroitinase AC strikingly alters the in vitro adhesion of palatal shelves. We also demonstrate the absence of this apical CSPG in the clefted palates of transforming growth factor beta 3 (TGF-beta(3)) null mutant mice, and its induction, together with palatal shelf adhesion, when TGF-beta(3) is added to TGF-beta(3) null mutant palatal shelves in culture. When chick palatal shelves (that do not adherein vivo nor express TGF-beta(3), nor CSPG in the MEE) are cultured in vitro, they do not express CSPG and partially adhere, but when TGF-beta(3) is added to the media, they express CSPG and their adhesion increases strikingly. We therefore conclude that the expression of CSPG on the apical surface of MEE cells is a key factor in palatal shelf adhesion and that this expression is regulated by TGF-beta(3).