Lipoma gástrico gigante en paciente adulta mayor con síntomas de obstrucción digestiva: Primer reporte de caso en el Perú / Giant gastric lipoma in an elderly patient with digestive obstruction symptoms: First case report in Peru

Los lipomas gástricos son una patología muy rara que representan el 5% de los lipomas gastrointestinales y menos del 1% de los tumores benignos del estómago. Los lipomas gástricos gigantes (≥ 4 cm) son extremadamente raros, habiéndose encontrado solo 32 casos reportados en la bibliografía. Reportamos el primer caso de un lipoma gástrico gigante en el Perú, operado por gastrectomía corporal por laparotomía en una paciente mujer de 79 años que acudió con un cuadro clínico de dos meses de evolución caracterizado por dolor abdominal en epigastrio más sensación de llenura precoz, deposiciones oscuras y pérdida de peso. Al examen físico se halló una masa palpable de aproximadamente 8 cm en hipocondrio izquierdo. La endoscopía digestiva alta reveló una lesión elevada en el tercio proximal del cuerpo gástrico de aproximadamente 30 mm. Se realizó un estudio tomográfico que evidenció una masa sospechosa de lipoma gástrico por lo que se procedió a realizar una gastrectomía corporal por laparotomía. El informe anatomopatológico confirmó el diagnóstico de lipoma gástrico gigante. En el posoperatorio no hubo complicaciones y fue dada de alta al séptimo día.

Gastric lipoma is a very rare condition, which accounts for 5% of gastrointestinal lipomas and for less than 1% of benign tumors of the stomach. Giant gastric lipomas (≥ 4 cm) are extremely rare, and we found only 32 cases reported in the literature. We report the first case of a giant gastric lipoma in Peru, which led to a corporal gastrectomy using a laparotomy approach in a 79-year old woman, who presented with a 2-month history with abdominal and epigastric pain, early fullness, dark stools, and weight loss. Physical examination revealed a 7- to 8-cm palpable mass in the left upper quadrant. Upper gastrointestinal endoscopy revealed an elevated lesion in the proximal third of the gastric body, measuring approximately 30-mm. A CT scan revealed a mass compatible with a gastric lipoma, so a corporal gastrectomy with a laparotomy approach was performed. The anatomopathological report confirmed the diagnosis of a giant gastric lipoma. There were no complications during the postoperative period, and the patient was discharged on the seventh post-op day.

Enfoque de riesgo de la meningoencefalitis aguda en niños ingresados en el Hospital Provincial de Ciego de Ávila / Focus risk of acute meningoencephalitis in children admitted to the Provincial Hospital in Ciego de Ávila

Introducción: entre las infecciones que afectan el sistema nervioso central se destacan, por su alta incidencia en la población infantil, las meningoencefalitis bacterianas y virales. Objetivo: determinar el comportamiento epidemiológico de un grupo de factores de riesgo y su asociación con la meningoencefalitis aguda en niños ingresados en el Hospital Provincial General Docente Dr. Antonio Luaces Iraola, de Ciego de Ávila, de enero de 2013 a abril de 2014. Método: se realizó un estudio observacional analítico de casos y controles pareados por edad y sexo; el universo estuvo constituido por 45 niños diagnosticados de meningoencefalitis aguda, y sus respectivos controles. La información se recolectó mediante un formulario; para caracterizar la población estudiada, en el análisis estadístico se determinaron las frecuencias absolutas y relativas; como medida del riesgo se calculó la oportunidad relativa. Resultados: la enfermedad fue más frecuente en los niños que presentaron factores de riesgo tales como antecedentes de infecciones respiratorias agudas altas, exposición al humo del tabaco inmunodeficiencia, malnutrición por defecto, prematuridad y condiciones de hacinamiento en la vivienda. Conclusiones: algunos de los factores de riesgo estudiados, cuando actúan de forma simultánea o multifactorial -a excepción del hacinamiento, la prematuridad, la no lactancia materna y la malnutrición por defecto-, tienen asociación estadísticamente significativa con la presentación de meningoencefalitis aguda en niños. Es posible reducir la incidencia de esta infección en edades pediátricas mediante el control o eliminación de factores de riesgo como la inmunodeficiencia, la exposición al humo del tabaco y las infecciones espiratorias agudas altas(AU)

Introduction: among infections that affect the central nervous system stand out, because of its high incidence in children, bacterial and viral meningoencephalitis.Objective: to determine the epidemiological behavior of a group of risk factors and their association with acute meningoencephalitis in children admitted to the Provincial General Teaching Hospital Dr. Antonio Luaces Iraola of Ciego de Ávila, from January 2013 to April 2014. Method: an observational analytical study of cases and controls matched by age and sex was carried out; the universe consisted of 45 children diagnosed with acute meningoencephalitis, and their respective controls. The information was collected through a form; in order to characterize the population studied, in the statistical analysis were determined absolute and relative frequencies; the odds ratio was calculated as a measure of risk.Results: the disease was more common in children who had risk factors such as a history of acute upper respiratory tract infections, exposure to smoke snuff, immunodeficiency, malnutrition by default, prematurity and overcrowded housing.Conclusions: some of the risk factors studied, when act in simultaneous or multifactorial way -except overcrowding, prematurity, not breastfeeding and malnutrition by default- have statistically significant association with the presentation of acute meningoencephalitis in children. It is possible to reduce the incidence of this infection in pediatric age by controlling or eliminating risk factors such as immunodeficiency, exposure to smoke snuff and high acute respiratory infections(AU)

Lack of Accuracy of Biomarkers and Physical Examination to Detect Bacterial Infection in Febrile Infants.

OBJECTIVES: The aim of this study was to analyze the usefulness of physical examination, C-reactive protein (CRP), procalcitonin (PCT), white blood cell (WBC) count, and absolute neutrophils counts (ANCs) for the diagnosis of invasive bacterial infections (IBIs) and potentially serious bacterial infections in infants younger than the age of 3 months presenting with fever without source (FWS) to the emergency department (ED). METHODS: A descriptive retrospective study that includes all infants aged younger than 3 months who presented with FWS to the ED between July 2008 and January 2012. We evaluated diagnostic performance for each test by receiver operating characteristic curve analysis. Sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio were also calculated. RESULTS: Three hundred eighteen patients met the inclusion criteria. Eleven bacteremia (3.5%) and 76 urinary tract infections (23.9%) were diagnosed. To detect IBI, the areas under the curve for the different tests were as follows: PCT, 0.77 (95% confidence interval [CI], 0.57-0.96); CRP, 0.54 (95% CI, 0.36-0.73); ANC, 0.53 (95% CI, 0.34-0.71); and WBC, 0.42 (0.24-0.61). To detect potentially serious bacterial infections, the areas under the curve were as follows: PCT, 0.66 (95% CI, 0.59-0.74); CRP, 0.68 (0.60-0.76); ANC, 0.64 (0.56-0.71); and WBC, 0.66 (0.58-0.72). CONCLUSIONS: Procalcitonin is better than CRP, WBC, and ANC to confirm or dismiss the presence of an IBI in infants aged younger than 3 months presenting with FWS to the ED. However, it could not identify almost 30% of infants with IBI. Most patients diagnosed with IBI (10 of 11) presented abnormal values in at least one of the analytical parameters and/or physical appearance. Four of 5 patients with IBI and well appearing presented abnormal results in at least one of the analytical parameters. Therefore, the development of tools combining different tests including the new biomarkers could increase the reliability of the tests for the diagnosis of IBI in these patients.

Prognostic Value of BRAF, PI3K, PTEN, EGFR Copy Number, Amphiregulin and Epiregulin Status in Patients with KRAS Codon 12 Wild-Type Metastatic Colorectal Cancer Receiving First-Line Chemotherapy with Anti-EGFR Therapy.

INTRODUCTION: Mutational analysis of RAS is required for anti-epidermal growth factor receptor (EGFR) treatment for patients with metastatic colorectal cancer (mCRC). However, most patients with KRAS wild-type tumors still do not respond. Other molecules downstream of the EGFR may also play a role in resistance to EGFR therapies. OBJECTIVE: Our objective was to investigate the clinical importance of biomarkers in relation to response, progression-free survival, and overall survival in patients with mCRC receiving first-line treatment with anti-EGFR therapy plus chemotherapy. METHODS: We studied the EGFR pathway [EGFR, NRAS, BRAF, PIK3CA, phosphatase and tensin homolog (PTEN), amphiregulin (AREG), and epiregulin (EREG)] in 105 patients with mCRC KRAS codon 12 wild type. We analysed objective response, progression-free survival, and overall survival in molecularly defined subgroups of the patients receiving anti-EGFR therapy plus chemotherapy as first-line treatment. RESULTS: We found a significant association between RAS wild-type, BRAF wild-type, EREG, and AREG overexpression and response to anti-EGFR therapy (p = 0.003, p = 0.015, p = 0.05, and p = 0.009, respectively). Progression-free survival and overall survival were lower in patients with RAS (p = 0.36 and p ≤ 0.001, respectively) or BRAF (p = 0.003 and p = 0.002, respectively) mutant tumors. Patients with EREG and AREG messenger RNA (mRNA) expression had longer survival than those with low-expression tumors; progression-free survival and overall survival were significant for AREG (p = 0.001 and p = 0.05, respectively). Patients with EGFR amplification tumors responded better to treatment and had better survival rates, although this was not significant. PIK3CA and PTEN were not associated with either response or survival. The multivariate logistic regression model for response showed only BRAF as a significant predictor after adjustment for the other covariates (p = 0.04, odds ratio 8.3, 95 % confidence interval 0.81-86.0). CONCLUSIONS: RAS, BRAF, AREG, and EREG predict for efficacy of first-line anti-EGFR therapy in patients with mCRC.

Pérdidas en el cromosoma 1p36 y la sobreexpresión de COX-2 predicen el intervalo libre de recurrencia en meningiomas completamente extirpados grados I y II / Chromosome 1p36 loss and COX-2 overexpression predict recurrence-free survival in completely removed meningioma grade I and II

Diversos estudios con un largo periodo de seguimiento muestran que la tasa de recidiva para los meningiomas grado I (benignos) y II (atípicos) se sitúa entre el 15-25% y el 30-35% respectivamente, a pesar de una cirugía agresiva. Hemos investigado 135 meningiomas completamente resecados para identificar y comparar marcadores pronósticos de recurrencia tumoral. Hemos determinado la expresión inmunohistoquímica de 30 biomarcadores, la muerte celular por apoptosis mediante un ensayo de hibridación in situ (ApopDETEKTM) y las perdidas en el cromosoma 1p36 mediante FISH. El análisis estadístico univariante mostró que el grado tumoral de la OMS, la alta celularidad, la atipia nuclear, las pérdidas en el cromosoma 1p36 (determinadas en 20 de los 107 casos válidos) y la expresión de COX-2 (9 casos positivos y 126 negativos), Ciclina A, Topoisomerasa II y MIB1/Ki67 se asociaron con el periodo libre de recurrencia. El análisis multivariante de estas variables pronósticas reveló que solamente las pérdidas en el cromosoma 1p36 y la expresión de COX-2 y MIB1 eran factores independientes para la predicción de recidiva tumoral. El análisis estadístico para la covariación de COX-2 y las perdidas en 1p36 mostraron un efecto antagonista para ambos marcadores. Los meningiomas con pérdidas en 1p36 mostraron un incremento significativo de la necrosis, la atipia nuclear y la expresión de Ciclina E, PAKT, PDGF y p21. La sobreexpresión de COX-2 se asocia a su vez con un aumento de la expresión de VEGF, PDGF, HER2 y MDM2. Los inhibidores selectivos de COX-2 podrían ser usados como un tratamiento quimiopreventivo putativo para evitar la recurrencia en aquellos meningiomas con sobreexpresión de COX-2(AU)

Long follow-up studies show that the 10-year regrowth rate for grade I (benign) and II (atypical) meningiomas rises up to 15---25% and 30---35%, respectively, despite aggressive surgery. We investigated completely removed meningiomas grade I and II (n = 135) to identify and compare prognostic markers for tumour recurrence. We determined the immunohistochemical expression of 30 biomarkers, cell death assay by in situ hybridisation (ApopDETEKTM) and loss of chromosome 1p36 by FISH. The univariate statistical analysis showed that WHO grade, high cellularity, nuclear atypia, loss of 1p36 (determined in 20 out of 107 valid cases), expression of COX-2 (9 positive cases and 126 negative cases), Cyclin A, Topoisomerase II and MIB1/ki67 were associated with recurrence-free survival. The multivariate linkage analysis for the prognostic variables revealed that only 1p36 loss, expression of COX-2 and MIB1 were independent factors for predicting meningioma recurrence. The statistical analysis of COX-2 and 1p36 loss co-variation showed an antagonistic effect for both prognostic markers. Meningiomas with 1p36 loss showed significant increase of necrosis, nuclear atypia and increased expression of Cyclin E, PAKT, PDGF and p21. COX-2 overexpression was associated with increased VEGF, PDGF, HER2 and MDM2 expression. COX-2 inhibitors may be used as a putative chemopreventive treatment for meningioma recurrence in tumours with COX-2 over-expression(AU)

Study of KRAS new predictive marker in a clinical laboratory.

BACKGROUND: The presence of somatic mutations in the KRAS gene has been identified as a reliable strong negative predictor for the response to targeting the epidermal growth factor receptor (EGFR), in patients with metastatic colorectal cancer and the use of anti-EGFR monoclonal antibodies such as Cetuximab and Panitumumab is now restricted to patients with no detectable KRAS mutations. Between 30 and 40 % of colorectal cancers contain a mutated KRAS oncogene. The aim of this study was to evaluate concordance between three methods to analyze KRAS mutational status in regard to clinical testing. METHODS: We analyzed KRAS mutations in codons 12 and 13 of exon 2 in one hundred formalin-fixed paraffin-embedded (FFPE) colorectal cancer samples by three different methods: Direct Sequencing and two commercial kits on allele-specific oligonucleotide hybridization (KRAS StripAssay, Vienna Lab.) and Amplification Refractory Mutation System/Scorpions (ARMS/S; TheraScreen KRAS Mutation kit DxS) based on q-PCR. RESULTS: We have found similar frequencies of KRAS mutations by TheraScreen and Strip-Assay (44 and 48 %), with a κ value of 0.90, indicating almost perfect agreement between methods. The frequency by direct sequencing was much lower (26 %) and the κ values were 0.67 (compared to TheraScreen) and 0.57 (compared to Strip-Assay) indicating low sensitivity. CONCLUSIONS: On analyzing KRAS mutation in FFPE tumor samples, direct sequencing sensitivity is too low to be used in a clinical setting. Choosing between ARMS/S; TheraScreen KRAS Mutation kit DxS and KRAS StripAssay, Vienna Lab, will depend on laboratory facilities and expertise.

Clinicopathological variables, immunophenotype, chromosome 1p36 loss and tumour recurrence of 247 meningiomas grade I and II.

The WHO grading scheme distinguishes benign (grade I), atypical (grade II) and anaplastic (grade III) meningiomas. Both atypical and anaplastic meningiomas exhibited an overall increased rate of recurrence, but between 15-20% benign meningiomas will also exhibit an unfavourable clinical course with recurrence before 10 years despite aggressive surgery. We investigated 247 cases of meningiomas grade I and II. The immunohistochemical expression of 30 different molecular biomarkers of cell adhesion molecules, cell-cycle and apoptosis regulators and checkpoints was analyzed. We also determined apoptosis by in-situ hybridization (APOPDETEKTM) and loss of chromosome 1p36 by FISH. The study revealed a statistically significant co-variation (p<0.05) between meningiomas grade II associated with several clinicopathological features (Simpson grade of clinical resection, necrosis, nuclear atypia, macronucleoli, transition to small cell, sheet-like growth, high cellularity), increased expression of several biomarkers of tumour proliferation (Cyclin A, Cyclin E, MIB-1 or MDM2), proteases (Cathepsin D) or cell-adhesion (CD44) and lower expression of progesterone receptors than meningiomas grade I. The presence of Psammoma bodies or the location at convexity were protective prognostic factors for tumour recurrence while high cellularity and early age of onset (<57 year-old) were indicators of increased recurrence risk. The expression of COX-2, gamma-catenin, Topoisomerase IIa, VEGF and MIB-1 was significantly higher in the cohort of recurrent meningiomas. Meningiomas with chromosome 1p36 loss showed a higher recurrence rate (33.3%) than meningiomas with normal chromosome 1p36 (18%). Increased COX-2 expression in recurrent meningioma may also suggest a putative role of COX-2 inhibitors as a chemopreventive treatment for recurrence.

Fortalecimiento de la vigilancia integrada de poliomielitis y otras enfermedades inmunoprevenibles en Angola basadas en la experiencia cubana / Strengthening of comprehensive surveillance of poliomyelitis and other immunopreventable diseases in Angola on the basis of the Cuban experience

Múltiples han sido los esfuerzos que se han llevado a cabo por la Organización Mundial de la Salud para la erradicación de la poliomielitis en el mundo, enfermedad que muestra una parálisis irreversible para toda la vida, acompañada de consecuencias económicas para la persona afectada y su entorno familiar. Por primera vez se lleva a cabo un proyecto de cooperación técnica entre países, fuera de las Américas, donde se puso de manifiesto una vez más la capacidad, fortaleza, entrega y potencialidad de la medicina cubana en el mundo. Participaron 20 médicos cubanos en una primera etapa (enero- julio 2008) y 7 en una segunda etapa (enero-abril 2009). El objetivo de esta colaboración se centró en el trabajo integral de grupo, en el fortalecimiento de la vigilancia, control de las enfermedades inmunoprevenibles, mejora de las coberturas de vacunación de rutina, formación de recursos humanos y apoyo en las campañas de vacunación. Se logró sensibilizar a una gran cantidad de personal de salud y a la comunidad para la identificación de las parálisis flácidas agudas, así como de otras enfermedades inmunoprevenibles; se fortaleció la búsqueda activa de casos y se reforzó la vigilancia, así como el apoyo y monitoreo de la calidad de las campañas de vacunación. Se trabajó por incrementar las coberturas de vacunación de rutina y la vigilancia integrada de estas dolencias. Una vez más se demuestra la incondicionalidad de los médicos cubanos para mitigar el dolor que causan estas enfermedades, acompañado del gran valor humano de la medicina cubana.

Many efforts have been made by the World Health Organization to eradicate poliomyelitis worldwide, a disease that causes irreversible paralysis for life in addition to adverse economic effects for the patient and his/her family as well. For the first time, there is a technical cooperation project between countries outside The Americas, in which the capabilities, strength, commitment and potentialities of the Cuban medicine was again stressed in the world. Twenty Cuban physicians were involved in the first phase (January-July 2008) and 7 in the second phase (January-April 2009). The objective of this cooperation was focused on comprehensive teamwork, strengthening of surveillance, control of immunopreventable diseases, improvement of regular vaccination coverage, formation of human resources and support to vaccination campaigns. It was possible to make a large amount of health workers and the community sensitive to the detection of acute flaccid paralysis as well as other immnopreventable diseases, to strengthen active search of cases, to reinforce surveillance and to support and monitor the quality of vaccination campaigns. The participants worked towards increasing the regular vaccination coverage and the comprehensive surveillance of these illnesses. Once again the full dedication of the Cuban physicians to relieve pain caused by these diseases and the great human value of the Cuban medicine was demonstrated.

Fortalecimiento de la vigilancia integrada de poliomielitis y otras enfermedades inmunoprevenibles en Angola basadas en la experiencia cubana / Strengthening of comprehensive surveillance of poliomyelitis and other immunopreventable diseases in Angola on the basis of the Cuban experience

Múltiples han sido los esfuerzos que se han llevado a cabo por la Organización Mundial de la Salud para la erradicación de la poliomielitis en el mundo, enfermedad que muestra una parálisis irreversible para toda la vida, acompañada de consecuencias económicas para la persona afectada y su entorno familiar. Por primera vez se lleva a cabo un proyecto de cooperación técnica entre países, fuera de las Américas, donde se puso de manifiesto una vez más la capacidad, fortaleza, entrega y potencialidad de la medicina cubana en el mundo. Participaron 20 médicos cubanos en una primera etapa (enero- julio 2008) y 7 en una segunda etapa (enero-abril 2009). El objetivo de esta colaboración se centró en el trabajo integral de grupo, en el fortalecimiento de la vigilancia, control de las enfermedades inmunoprevenibles, mejora de las coberturas de vacunación de rutina, formación de recursos humanos y apoyo en las campañas de vacunación. Se logró sensibilizar a una gran cantidad de personal de salud y a la comunidad para la identificación de las parálisis flácidas agudas, así como de otras enfermedades inmunoprevenibles; se fortaleció la búsqueda activa de casos y se reforzó la vigilancia, así como el apoyo y monitoreo de la calidad de las campañas de vacunación. Se trabajó por incrementar las coberturas de vacunación de rutina y la vigilancia integrada de estas dolencias. Una vez más se demuestra la incondicionalidad de los médicos cubanos para mitigar el dolor que causan estas enfermedades, acompañado del gran valor humano de la medicina cubana(AU)

Many efforts have been made by the World Health Organization to eradicate poliomyelitis worldwide, a disease that causes irreversible paralysis for life in addition to adverse economic effects for the patient and his/her family as well. For the first time, there is a technical cooperation project between countries outside The Americas, in which the capabilities, strength, commitment and potentialities of the Cuban medicine was again stressed in the world. Twenty Cuban physicians were involved in the first phase (January-July 2008) and 7 in the second phase (January-April 2009). The objective of this cooperation was focused on comprehensive teamwork, strengthening of surveillance, control of immunopreventable diseases, improvement of regular vaccination coverage, formation of human resources and support to vaccination campaigns. It was possible to make a large amount of health workers and the community sensitive to the detection of acute flaccid paralysis as well as other immnopreventable diseases, to strengthen active search of cases, to reinforce surveillance and to support and monitor the quality of vaccination campaigns. The participants worked towards increasing the regular vaccination coverage and the comprehensive surveillance of these illnesses. Once again the full dedication of the Cuban physicians to relieve pain caused by these diseases and the great human value of the Cuban medicine was demonstrated(AU)

Regulation of the expression of prostate apoptosis response protein 4 (Par-4) in rat granulosa cells.

The par-4 gene, directs the expression of a protein in the rat ventral prostate after apoptotic stimuli but not growth stimulatory, growth arresting or necrotic signals. Since Par-4 expression appears to be ubiquitous we investigated the possibility of Par-4 having a role in the rat ovary granulosa cells apoptotic death. Par-4 mRNA was detected by RT-PCR with oligonucleotides designed to prime Par-4 leucine zipper in the ovaries of 12 day old rats and reached the higher levels in 24 days old rats. In situ hybridization analysis revealed that Par-4 expression is restricted to granulosa cells. PMSG priming of 24 day old rats for 2 days greatly reduced Par-4 expression in granulosa cells as determined by in situ hybridization, RT-PCR of mRNA and protein immunodetection with Western blot. Granulosa cells placed in serum-fee culture, exhibited increased levels of Par-4 mRNA and protein, in good correlation with the degree of apoptosis. The culture-induced increases in Par-4 are significantly prevented by FSH. Transient transfection of granulosa cells with Par-4 leucine zipper domain that functions as a dominant-negative regulator of Par-4 activity resulted in lower rates of apoptosis while overexpression of the full length Par-4 counteracted FSH effects on apoptosis. Par-4 association with PKCzeta which is supposed to inhibit this kinase mediated antiapoptotic way is also prevented by FSH and, FSH antiapoptotic effects are counteracted by a PKCzeta specific inhibitor. These findings indicate that FSH by suppressing Par-4 expression in the ovary activates PKCzeta-dependent antiapoptotic pathway and suggest that Par-4 is part of the mechanism underlying granulosa cells apoptotic demise.

Disruption of the beta3 663-687 disulfide bridge confers constitutive activity to beta3 integrins.

The platelet fibrinogen receptor, integrin alphaIIbbeta3, is a noncovalent heterodimer of glycoproteins IIb and IIIa. This work was aimed at elucidating the role played by the carboxy-terminal extracellular, trans-membrane, and cytoplasmic regions of the glycoprotein beta3 in the formation of functional complexes with alpha subunits. Progressive carboxy-terminal deletions of beta3 revealed that surface exposure of alphaIIbbeta3 or alphavbeta3 could not occur in the absence of the transmembrane domain of beta3. In contrast, internal deletions 616 to 690 of the carboxy-terminal regions of the beta3 ectodomain led to surface exposure of constitu tive active receptors in CHO cells, as indicated by the enhanced rate of cell adhesion to immobilized ligands and spontaneous binding to soluble fibrinogen or activation-dependent antibody PAC-1. The functional analysis of cysteine mutations within the 616 to 690 region of beta3 or chimeric beta3-beta7 subunits revealed that disruption of the C663-C687 disulfide bridge endows constitutive activity to the alphaIIbbeta3 receptor. It is concluded that the carboxy-terminal tail of the beta3 ectodomain, so-called beta tail domain (betaTD), is not essential for cell surface expression of beta3 receptors. However, a basal, nonactivated, low ligand-affinity state of the beta3 integrins demands a normal conformation of this domain.