Impact of age on the use of adjuvant treatments in patients undergoing surgery for colorectal cancer: patients with stage III colon or stage II/III rectal cancer.

BACKGROUND: Many older patients don't receive appropriate oncological treatment. Our aim was to analyse whether there are age differences in the use of adjuvant chemotherapy and preoperative radiotherapy in patients with colorectal cancer. METHODS: A prospective cohort study was conducted in 22 hospitals including 1157 patients with stage III colon or stage II/III rectal cancer who underwent surgery. Primary outcomes were the use of adjuvant chemotherapy for stage III colon cancer and preoperative radiotherapy for stage II/III rectal cancer. Generalised estimating equations were used to adjust for education, living arrangements, area deprivation, comorbidity and clinical tumour characteristics. RESULTS: In colon cancer 92% of patients aged under 65 years, 77% of those aged 65 to 80 years and 27% of those aged over 80 years received adjuvant chemotherapy (χ2trends < 0.001). In rectal cancer preoperative radiotherapy was used in 68% of patients aged under 65 years, 60% of those aged 65 to 80 years, and 42% of those aged over 80 years (χ2trends < 0.001). Adjusting by comorbidity level, tumour characteristics and socioeconomic level, the odds ratio of use of chemotherapy compared with those under age 65, was 0.3 (0.1-0.6) and 0.04 (0.02-0.09) for those aged 65 to 80 and those aged over 80, respectively; similarly, the odds ratio of use of preoperative radiotherapy was 0.9 (0.6-1.4) and 0.5 (0.3-0.8) compared with those under 65 years of age. CONCLUSIONS: The probability of older patients with colorectal cancer receiving adjuvant chemotherapy and preoperative radiotherapy is lower than that of younger patients; many of them are not receiving the treatments recommended by clinical practice guidelines. Differences in comorbidity, tumour characteristics, curative resection, and socioeconomic factors do not explain this lower probability of treatment. Research is needed to identify the role of physical and cognitive functional status, doctors' attitudes, and preferences of patients and their relatives, in the use of adjuvant therapies.

Predictors of 1- and 2-year mortality in patients with rectal cancer.

AIM: Tools are needed to aid in the assessment of the prognosis of patients with rectal cancer regarding the risk of medium-term mortality. The aim of this study was to develop and validate clinical prediction rules for 1- and 2-year mortality in patients undergoing surgery for rectal cancer. METHOD: A prospective cohort study of patients diagnosed with rectal cancer who underwent surgery was carried out. The main outcomes were mortality at 1 and 2 years after surgery. Background, clinical parameters and diagnostic test findings were evaluated as possible predictors. Multivariable survival models were used in the statistical analyses. RESULTS: Predictors of 1-year mortality were being a current smoker [hazard ratio (HR) 4.98], having a Charlson index adjusted by age > 5 (HR 2.61), the presence of vascular, perineural or lymphatic invasion (HR 3.30), the presence of residual tumour at the operation (R-stage) (HR 8.64) and TNM stage (HR for TNM IV 5.10) [concordance index (C-index) 0.799 (95% CI: 0.71-0.89)]. Age greater than 80 years (HR 2.19), being a current smoker (HR 2.20), the pre-intervention haemoglobin level (HR 2.02), need for blood transfusion (HR 2.12), vascular, perineural or lymphatic invasion (HR 2.59), R-stage of the operation (HR 6.13) and TNM stage (HR for TNM IV 4.43) were predictors of 2-year mortality [C-index 0.779 (0.718-0.840)]. Adjuvant chemotherapy was an additional predictor at both outcome durations. CONCLUSION: These clinical parameters show good predictive values and are easy and quick-to-use tools to help in clinical decision making.

Association between social support, functional status, and change in health-related quality of life and changes in anxiety and depression in colorectal cancer patients.

OBJECTIVE: The aim of this study was to explore the association between baseline social support, functional status, and change in health-related quality of life (HRQoL) in colorectal cancer patients and change in anxiety and depression measured by Hospital Anxiety and Depression Scale (HADS) at 1 year after surgery. METHODS: Consecutive patients who were due to undergo therapeutic surgery for the first time for colon or rectal cancer in 9 hospitals in Spain were eligible for the study. Patients completed the following questionnaires before surgery and 12 months afterward: 1 HRQoL instrument, the European Organization for Research and Treatment of Cancer Core Quality of Life Questionnaire; a social support questionnaire, the Duke-UNC Functional Social Support Questionnaire; the Barthel Index, to assess functional status; the HADS, to assess anxiety and depression; and questions about sociodemographic information. General linear models were built to explore the association between social support, functional status, and change in HRQoL and changes in anxiety and depression 12 months after surgery. RESULTS: A total of 947 colorectal cancer patients took part in the study. Patients' functional status, social support, and change in HRQoL were associated with changes in anxiety and depression. Greater social support and improvements in physical, cognitive, and social functioning and in insomnia resulted in improvements in anxiety and depression. No functionally independent patients were associated with lesser improvements in anxiety and depression. CONCLUSIONS: Colorectal cancer patients who have more social support, are functionally independent and have higher improvements in HRQoL may have better results in anxiety and depression at 1 year after surgery, adjusting for age, gender, location, occupation, and baseline HADS scores.

Association of social support, functional status, and psychological variables with changes in health-related quality of life outcomes in patients with colorectal cancer.

BACKGROUND: The aim of this study was to explore the association of social support received, and functional and psychological status of colorectal cancer patients before surgery with changes in health-related quality of life (HRQoL) outcomes measured by EORTC QLQ-C30 at 1-year post-intervention. METHODS: Consecutive patients that were because of undergo therapeutic surgery for the first time for colon or rectum cancer in nine hospitals in Spain were eligible for the study. Patients completed questionnaires before surgery and 12 months afterwards: one HRQoL instrument, the EORTC QLQ-C30; a social network and social support questionnaire, the Duke-UNC Functional Social Support Questionnaire; the Hospital Anxiety and Depression Scale, to assess anxiety and depression; and the Barthel Index, to assess functional status; as well as questions about sociodemographic information. General linear models were built to explore the association of social support, functional status, and psychological variables with changes in HRQoL 12 months after intervention. RESULTS: A total of 972 patients with colorectal cancer took part in the study. Patients' functional status, social support, and anxiety and depression were associated with changes in at least one HRQoL domain. The higher functional status, and the higher social support, the more they improved in HRQoL domains. Regarding anxiety and depression, the more anxiety and depression patients have at baseline, less they improve in HRQoL domains. CONCLUSIONS: Patients with colorectal cancer who have more social support and no psychological distress may have better results in HRQoL domains at 1 year after surgery. Copyright © 2015 John Wiley & Sons, Ltd.

Late renal vein thrombosis associated with recurrence of membranous nephropathy in a renal allograft: a case report.

Allograft renal vein thrombosis (RVT) is an uncommon but potentially catastrophic complication. Although it usually occurs in the early posttransplant period and is associated with surgical complications or vascular rejection, it may develop later, when it is generally related with a hypercoagulable state. Typical clinical presentation is sudden oligoanuric acute renal failure, and hematuria, with a painful and swollen renal allograft. Confirmation of the diagnosis requires Doppler ultrasound and computed tomography. Herein we have reported a successfully treated case of late RVT that developed in an allograft with recurrent membranous nephropathy associated with the nephrotic syndrome. The patient fully recovered renal graft function a few days after presentation, which was related to anticoagulant therapy. We demonstrated complete recanalization of the venous thrombosis.

Registro Iberoamericano de Espondiloartritis (RESPONDIA): Argentina / RESPONDIA. Iberoamerican spondyloarthritis Registry: Argentina

Objetivo: Describir las principales características de las espondiloartritis (SpA) en la población argentina. Material y métodos: Se realizó un análisis descriptivo y transversal de la información recogida entre marzo y diciembre de 2007 y almacenada en línea, en la página electrónica del grupo Registro de Espondiloartritis de la Sociedad Española de Reumatología (REGISPONSER). Participaron 11 centros de Argentina, siguiendo todos similares pautas de evaluación del paciente y de registro de datos. Resultados: Se incluyó a 405 pacientes con SpA, 238 varones (59%), con una edad media desviación estándar de 48,1 15,7 años y un tiempo de evolución medio de la enfermedad de 10,9 9,5 años. La artritis psoriásica (APs) fue el diagnóstico prevalente (46,7%), y siguiendo en orden de frecuencia estaban la espondilitis anquilosante (EA) (30,3%) y la SpA indiferenciada (12,4%). La edad al inicio fue de 38,4 16,6 años y el tiempo de evolución hasta el diagnóstico fue de 7,5 8,6 años. Los síntomas de inicio más frecuentes fueron artritis periférica (66%), lumbalgia (54%) y sacroileítis (39%). El 43% presentó dactilitis y el 10%, uveítis durante la evolución de la enfermedad. El tratamiento incluyó inhibidores del factor de necrosis tumoral en un 10,4% de los pacientes. El BASDAI promedio fue de 4 2,5 puntos y el BASFI, de 3,3 2,9 puntos. Los pacientes con EA presentaron una edad menor, más discapacidad laboral, más dolor, una afectación axial mayor y más daño radiológico que los pacientes con APs. Regis Conclusión: Los pacientes de Argentina con SpA presentan las clásicas características de afectación axial y periférica, y con frecuencia presentan manifestaciones extraarticulares (AU)

Objective: To describe the principal characteristics of spondyloarthritis in the Argentina population. Material and methods: A descriptive transversal study was carried out with information obtained between March and December 2007 and stored online at the Spondyloarthropathy Records website of the Spanish Society for Rheumatology (REGISPONSER). Eleven Argentine Centers participated and they all adopted similar criteria to assess patients and data were collected in the same database. Results: A total of 405 patients with spondyloarthritis (SpA) were included: 238 were males (59%) with an average age standard deviation 48.1 15.7 years and an average disease progress of 10.9 9.5 years. The majority was diagnosed with psoriatic arthritis (PsA) (46.7%), followed by ankylosing spondylitis (AS) (30.3%) and undifferentiated spondyloarthritis (U-SpA) (12.4%). Average age at onset was 38.4 16.6 years and time until diagnosis was 7.5 8.6 years. The most common initial symptoms were peripheral arthritis (66%), lumbago (54%) and sacroiliitis (39%). 43% of these patients presented dactylitis and 10% uveitis during the disease Obj progress. TNF inhibitor treatment was administered in 10.4% of the patients. Average BASDAI score was 4 2.5 and BASFI 3.3 2.9. Patients with ankylosing spondylitis were younger, showed a higher incapacity for work, felt more pain and presented more axial disorders and more evidence of radiologic damage than psoriatic arthritis patients. Conclusion. Argentina spondyloarthritis patients presented classical characteristics of axial and peripheral disorders and extraarticular symptoms were common (AU)

Influencia de factores sociodemográficos en actividad de enfermedad, estadofuncional y calidad de vida de pacientes con artritis psoriásica / Influence of sociodemographic features on clinical manifestations, disease activity, functional status and quality of life of patients with psoriatic artritis

Objetivo: Determinar la influencia de factores sociodemográficos en las manifestaciones clínicas, actividad de la enfermedad, estado funcional y calidad de vida de pacientes con artritis psoriásica (APs). Métodos: Se incluyeron 148 pacientes con APs reclutados de varios centros de reumatología de Argentina. Se determinaron factores sociodemográficos: edad, sexo, raza, nivel de educación, fuentes de ingreso personal, escala de Graffar y clases sociales. Al inicio de la enfermedad se evaluaron las siguientes variables: edad al inicio, duración de la enfermedad, manifestaciones clínicas y forma clínica de presentación. La actividad de la enfermedad fue evaluada mediante número de articulaciones activas, escala visual análoga (EVA) global del paciente y BASDAI. El estado funcional y la calidad de vida de los pacientes se determinó por medio de BASFI, ASQoL y SF-12 (Versión 1.0). Para el análisis estadístico de los datos obtenidos se utilizó test de Chi-cuadrado, test exacto de Fisher y test de Kruskal-Wallis. Resultados: De los 148 pacientes, 58,8% fueron mujeres con una edad media al inicio de la enfermedad de 53,2 ± 13,6 años y una duración media de enfermedad de 9,3 ± 8,9 años. La edad al inicio, el sexo, la raza y la escala de Graffar no estuvieron asociados con manifestaciones clínicas, actividad de la enfermedad, estado funcional y calidad de vida

Calidad del registro de quimioterapia en los servicios de farmacia hospitalaria de Andalucía / Chemotherapy registry quality in Andalusian hospital pharmacy departments

Objetivo: Analizar la calidad de los registros de las unidadescentralizadas de citostáticos de los hospitales de Andalucía y la disponibilidadde datos para analizar la utilización de estos fármacos.Método: Se elaboró un cuestionario ad hoc, usando variablesrelativas a la cobertura de información sobre pacientes y tratamientos,grado de informatización y organización. Los cuestionarios secumplimentaron en septiembre de 2005 mediante encuesta al responsablede los tratamientos quimioterápicos de los 19 servicios defarmacia de los hospitales que tratan pacientes oncológicos enAndalucía.Resultados: La tasa de respuesta fue del 100%, aunque un serviciono contaba con unidad centralizada de citostáticos. La coberturade preparación centralizada fue del 89% para hospital de día, el84% para pacientes ingresados, el 79% para pacientes hematológicosy el 69% para pacientes pediátricos. El registro está informatizadosólo en 13 hospitales (68%), con una gran variabilidad en losprogramas usados. La dispensación de temozolamida y de capecitabinacuenta con registro propio en el 68 y 42% de los casos. El nombredel paciente y el nombre y la dosis del citostático son los únicosdatos que se registran en todos, mientras que el nombre del protocolosólo se registra en el 47%, el diagnóstico, estadiaje y clasificaciónTNM en el 58, 31 y 16% respectivamente.Conclusiones: Existe una gran variabilidad en los sistemas deinformación para la gestión de uso de citostáticos, y carenciasimportantes en la disponibilidad de datos del paciente para realizarestudios de utilización y adecuación de la prescripción

Objective: To analyze registry quality in centralized cytostatictherapy units in Andalusian hospitals, and the availability of datato analyze the use of these drugs.Method: An ad hoc questionnaire was designed using variablesrelated to information coverage on patients and their treatments,data processing extent, and organization. Questionnaireswere completed in September 2005 by surveying people responsiblefor chemotherapy in all 19 pharmacy departments inAndalusian hospitals that treat oncologic patients.Results: Response rate was 100%, but one department hadno centralized cytostatic therapy unit. Centralized preparationcoverage was 89% for the day hospital, 84% for inpatients, 79%for hematologic patients, and 69% for pediatric patients. Registriesare computerized in only 13 hospitals (68%) with a varietyof software programs. Temozolamide and capecitabine dispensationhas a separate registry in 68% and 42% of cases, respectively.Patient name, and cytostatic name and dosage are the onlydata recorded in all instances, while protocol name is only recordedin 47%, and diagnosis, staging, and TNM categorization in58%, 31%, and 16% of cases, respectively.Conclusions: There is great variability regarding informationsystems for cytostatic use management, and a relevant shortage ofpatient data available for prescription use and adaptation studies

[Chemotherapy registry quality in Andalusian hospital pharmacy departments]. / Original breve Calidad del registro de quimioterapia en los servicios de farmacia hospitalaria de Andalucía.

OBJECTIVE: To analyze registry quality in centralized cytostatic therapy units in Andalusian hospitals, and the availability of data to analyze the use of these drugs. METHOD: An ad hoc questionnaire was designed using variables related to information coverage on patients and their treatments, data processing extent, and organization. Questionnaires were completed in September 2005 by surveying people responsible for chemotherapy in all 19 pharmacy departments in Andalusian hospitals that treat oncologic patients. RESULTS: Response rate was 100%, but one department had no centralized cytostatic therapy unit. Centralized preparation coverage was 89% for the day hospital, 84% for inpatients, 79% for hematologic patients, and 69% for pediatric patients. Registries are computerized in only 13 hospitals (68%) with a variety of software programs. Temozolamide and capecitabine dispensation has a separate registry in 68% and 42% of cases, respectively. Patient name, and cytostatic name and dosage are the only data recorded in all instances, while protocol name is only recorded in 47%, and diagnosis, staging, and TNM categorization in 58%, 31%, and 16% of cases, respectively. CONCLUSIONS: There is great variability regarding information systems for cytostatic use management, and a relevant shortage of patient data available for prescription use and adaptation studies.

Structure and function of the stalk, a putative regulatory element of the yeast ribosome. Role of stalk protein phosphorylation.

The ribosomal stalk is involved directly in the interaction of the elongation factors with the ribosome during protein synthesis. The stalk is formed by a complex of five proteins, four small acidic polypeptides and a larger protein which directly interacts with the rRNA at the GTPase center. In eukaryotes, the acidic components correspond to the 12 kDa P1 and P2 proteins, and the RNA binding component is protein P0. All these proteins are found to be phosphorylated in eukaryotic organisms. Previous in vitro data suggested this modification was involved in the activity of this structure. To confirm this possibility a mutational study has shown that phosphorylation takes place at a serine residue close to the carboxyl end of proteins P1, P2 and P0. This serine is part of a consensus casein kinase II phosphorylation site. However, by using a yeast strain carrying a temperature sensitive mutant, it has been shown that CKII is probably not the only enzyme responsible for this modification. Three new protein kinases, RAPI, RAPII and RAPIII, have been purified and compared with CKII and PK60, a previously reported enzyme that phosphorylates the stalk proteins. Differences among the five enzymes have been studied. It has also been found that some typical effectors of the PKC kinase stimulate the in vitro phosphorylation of the stalk proteins. All the data available suggest that phosphorylation, although it is not involved in the interaction of the acidic proteins with the ribosome, affects ribosome activity and might participate in some ribosome regulatory mechanism.

Phosphorylation of the yeast ribosomal stalk. Functional effects and enzymes involved in the process.

The ribosomal stalk is directly involved in the interaction of the elongation factors with the ribosome during protein synthesis. The stalk is formed by a complex of five proteins, four small acidic polypeptides and a larger protein which directly interacts with the rRNA at the GTPase center. In eukaryotes the acidic components correspond to the 12-kDa P1 and P2 proteins, and the RNA binding component is the P0 protein. All these proteins are found phosphorylated in eukaryotic organisms, and previous in vitro data suggested this modification was involved in the activity of this structure. Results from mutational studies have shown that phosphorylation takes place at a serine residue close to the carboxy end of the P proteins. Modification of this serine residue does not affect the formation of the stalk and the activity of the ribosome in standard conditions but induces an osmoregulation-related phenotype at 37 degrees C. The phosphorylatable serine is part of a consensus casein kinase II phosphorylation site. However, although CKII seems to be responsible for part of the stalk phosphorylation in vivo, it is probably not the only enzyme in the cell able to perform this modification. Five protein kinases, RAPI, RAPII and RAPIII, in addition to the previously reported CKII and PK60 kinases, are able to phosphorylate the stalk proteins. A comparison of the five enzymes shows differences among them that suggest some specificity regarding the phosphorylation of the four yeast acidic proteins. It has been found that some typical effectors of the PKC kinase stimulate the in vitro phosphorylation of the stalk proteins. All the data suggest that although phosphorylation is not involved in the interaction of the acidic P proteins with the ribosome, it can affect the ribosome activity and might participate in a possible ribosome regulatory mechanism.

Discapseudes holthuisi (Crustacea: Tanaidacea) as an intermediate host of Caballerorhynchus lamothei (Acanthocephala: Cavisomidae).

The intermediate host of the acanthocephalan Caballerorhynchus lamothei Salgado-Maldonado, 1977, is reported for the first time. Cystacanths of C. lamothei were found in the hemocoel of the tanaid shrimp Discapseudes holthuisi Bacescu and Gutu, 1975, in Alvarado and Sontecomapan lagoons, Veracruz, Mexico. This is the first report of a palaeacanthocephalan using a tanaid shrimp as an intermediate host. Prevalence by locality, shrimp length, sex and developmental stage, and an analysis of the distribution of number of cystacanths per host are presented. A higher prevalence, and percentage of multiple infections and larger host size were found in Alvarado Lagoon.

The GTPase center protein L12 is required for correct ribosomal stalk assembly but not for Saccharomyces cerevisiae viability.

Protein L12, together with the P0/P1/P2 protein complex, forms the protein moiety of the GTPase domain in the eukaryotic ribosome. In Saccharomyces cerevisiae protein L12 is encoded by a duplicated gene, rpL12A and rpL12B. Inactivation of both copies has been performed and confirmed by Southern and Western analyses. The resulting strains are viable but grow very slowly. Growth rate is recovered upon transformation with an intact copy of the L12 gene. Ribosomes from the disrupted strain lack protein L12 but are able to carry out translation in vitro at about one fourth of the control rate. The L12-deficient ribosomes have also a defective stalk containing standard amounts of the 12-kDa acidic proteins P1beta and P2alpha, but proteins P1alpha and P2beta are drastically reduced. Moreover, the affinity of P0 is reduced in the defective ribosomes. Footprinting of the 26 S rRNA GTPase domain indicates that protein L12 protects in different extent residues G1235, G1242, A1262, A1270, and A1272 from chemical modification. The results in this report indicate that protein L12 is not essential for cell viability but has a relevant role in the structure and stability of the eukaryotic ribosomal stalk.

[Duodenogastric reflux: validation study of its endoscopic visualization]. / Reflujo duodenogástrico: estudio de validación de su visualización endoscópica.

BACKGROUND: Duodenogastric reflux is a normal event that can be deleterious to the esophagic or gastric mucosa, depending on its magnitude, persistence, composition and gastric pH. There is not a definitive method to measure this phenomenon. AIM: To compare the endoscopic visualization of duodenogastric reflux with the quantitation of total bile acids in fasting gastric content (QTBA). PATIENTS AND METHODS: The presence of duodenogastric reflux, defined as the staining of gastric walls with bile during upper gastrointestinal endoscopy, was assessed in 62 patients (26 male), aged 21 to 73 years old. During the week after the endoscopy a sample of fasting gastric content was obtained to measure QTBA, using an enzymatic method. RESULTS: Median QTBA was 0.205 mumol/gastric residue. Fourteen of 31 patients with QTBA values over the median had endoscopically visible duodenogastric reflux, whereas 1 of 31 with values below the median had visible reflux (p < 0.001). CONCLUSIONS: Endoscopic visualization of duodenogastric reflux is statistically associated to the quantitation of total bile acids in fasting gastric residue.

Phosphorylation of the acidic ribosomal P proteins in Saccharomyces cerevisiae: a reappraisal.

Previous reports had pointed to serines 62 and 71/79 as possible phosphorylation sites in the yeast acidic ribosomal proteins YP1 alpha and YP2 alpha, respectively. However, it has been found that mutation of these serine residues did not affect the phosphorylation level of the proteins. A detailed examination of the YP2 alpha tryptic digest from the in vivo labeled protein demonstrates the existence of a totally trypsin-insensitive site at lysine 88 that led to a misinterpretation of previous results. The unique YP2 alpha tryptic phosphopeptide obtained contains, in addition to serines 71 and 79, a serine at position 96 near the carboxyl end, which automatic Edman degradation confirmed as the phosphorylated residue. In addition, by using Staphyloccocus protease V8, it was possible to obtain phosphopeptides containing only serine 96, whose phosphorylation has likewise been confirmed by radioactive labeling as well as by chemical methods. A similar analysis of the other 12 kDa acidic proteins, YP1 alpha, YP1 beta, and YP2 beta, has shown the presence of equivalent phosphorylation sites in the four P proteins, which correspond to position 96 in proteins YP1 alpha, YP1 beta, and YP2 alpha and position 100 in YP2 beta. This conclusion has been confirmed by the fact that mutation of serine 96 in proteins YP1 alpha and YP2 alpha abolishes their capacity to be phosphorylated in vivo. The mutation of the phosphorylation site of the individual acidic proteins seems not to alter their interaction with the ribosome. However, it has been found that the level of phosphorylation of the stalk proteins has an effect on the response of the cells to some specific metabolic conditions, indicating that it may modulate the translation of specific proteins.

Nutrición en el niño con daño neurológico / Nutrition in the neurologically damaged child

Los niños con daño neurológico tienen frecuentemente dificultades para alimentarse y crecer, por diferentes factores y hace falta normas sistematizadas que orienten su manejo. Tomando a la parálisis cerebral como modelo, en esta revisión se analizan algunos aspectos nutricionales que inciden en su evolución, con especial énfasis en evaluación nutricional, conducta alimentaria, complicaciones y tratamiento nutricional. Asimismo se mencionan ciertas interacciones de medicamentos con la nutrición y algunas dificultades éticas que pueden presentarse

Proteins P1, P2, and P0, components of the eukaryotic ribosome stalk. New structural and functional aspects.

The eukaryoic ribosomal stalk is thought to consist of the phosphoproteins P1 and P2, which form a complex with protein PO. This complex interacts at the GTPase domain in the large subunit rRNA, overlapping the binding site of the protein L11-like eukaryotic counterpart (Saccharomyces cerevisiae protein L15 and mammalian protein L12). An unusual pool of the dephosphorylated forms of proteins P1 and P2 is detected in eukaryotic cytoplasm, and an exchange between the proteins in the pool and on the ribosome takes place during translation. Quadruply disrupted yeast strains, carrying four inactive acidic protein genes and, therefore, containing ribosomes totally depleted of acidic proteins, are viable but grow with a doubling time threefold higher than wild-type cells. The in vitro translation systems derived from these stains are active but the two-dimensional gel electrophoresis pattern of proteins expressed in vivo and in vitro is partially different. These results indicate that the P1 and P2 proteins are not essential for ribosome activity but are able to affect the translation of some specific mRNAs. Protein PO is analogous to bacterial ribosomal protein L10 but carries an additional carboxyl domain showing a high sequence homology to the acidic proteins P1 and P2, including the terminal peptide DDDMGFGLFD. Successive deletions of the PO carboxyl domain show that removal of the last 21 amino acids from the PO carboxyl domain only slightly affects the ribosome activity in a wild-type genetic background; however, the same deletion is lethal in a quadruple disruptant deprived of acidic P1/P2 proteins. Additional deletions affect the interaction of PO with the P1 and P2 proteins and with the rRNA. The experimental data available support the implication of the eukaryotic stalk components in some regulatory process that modulates the ribosomal activity.