NEUROENDOCRINE TUMORS OF THE LUNG WITH SURGICAL RESECTION AND LYMPH NODE DISSECTION IN A TERTIARY THORACIC SURGERY CENTER.

CONTEXT: Management of neuroendocrine tumors is highly dynamic, in both diagnosis and treatment. OBJECTIVE: Surgical resection with lymph node approach offers excellent 5-years survival. DESIGN: Between 2008 and 2011 we operated with radical intent 326 lung cancers. PATIENTS AND METHODS: Cases without lymph node approach were excluded. We found 38 neuroendocrine malignancies: 12 typical carcinoids, 3 atypical carcinoids, 4 large cell neuroendocrine carcinomas (LCNEC) and 10 small-cell lung cancers (SCLC). Limits of the study are: variable lymphadenectomy technique; absence of PET - CT and EBUS-TBNA (EndoBronchial UltraSound - TransBronchial Needle Aspiration) for staging; incomplete data for disease-free survival. RESULTS: We performed 13 pneumonectomies, 22 lobectomies and 3 non-anatomical resections. There were 5 bronchoplasties. The 5-year survival difference between NSCLC (non-small-cell lung cancer - 42.9%) and SCLC (40.53% - one of the best from the literature) is not statistically significant (p=0.4780). Five-years survival was 100% for typical and atypical carcinoids - the best published. We found lymph node metastasis in 2 typical carcinoids, in 2 atypical carcinoids and in 6 SCLCs. CONCLUSIONS: For typical and atypical carcinoids, radical resection with lymphadenectomy offers 100% 5-years survival. Early-stage SCLC may benefit from radical resection; lymph node dissection is mandatory because of the well-known precocious lymphatic dissemination.

Bronchoanastomotic and bronchoplastic resections in pulmonary malignancy retrospective study 2000 - 2009.

UNLABELLED: Bronchial resections are surgical procedures in which bronchial continuity is interrupted, followed by reconstruction of resected ends through terminal anastomosis or various forms of plastic procedures. The purpose of these interventions is to preserve functional lung parenchyma. These procedures are indicated in tumors with central location as an alternative to pneumonectomies, serving to preserve maximum functional lung parenchyma. MATERIAL AND METHODS: We considered bronchoanastomotic and bronchoplastic procedures performed in our clinic over the period 2000-2009, for malignancy. There were 52 bronchoanastomotic resections and 9 bronchoplastic resections of which we analysed 40 bronchoanastomotic resections and 4 bronchoplastic resections (44 cases) ± associated resection. We excluded cases with non-malignant pathology or those with incomplete data at the beginning of the study. RESULTS: The importance of the main factors involved in relation with survival was calculated. We considered the type of surgery performed, histological type, TNM stage, and characteristics of the study group (age, sex). We found statistically significant correlations between survival and histopathology of malignancy with a better survival for lung carcinoids, especially for typical carcinoid tumors. TNM stage did not significantly influence survival, but N2 nodal involvement,according to the statistics, shows a poor prognosis. Age is another statistical significant factor correlated with post operative life expectancy, patients over 65 years old having a worse postoperative survival. CONCLUSIONS: In the corresponding lung malignant pathology, bronchoanastomotic bronchoplastic resections are indicated,but one must take into account the patient's age before submission to surgery, the histopathologic type and N2 nodal involvement.

Cervico-mediastinal thyroid masses - our experience.

INTRODUCTION: Over the last decades, several definitions and classifications of cervico-mediastinal goiters and thyroid masses have been proposed. We analyze and discuss the clinical presentation, the diagnostic procedures and the surgical technique in relation to post-operative complications and results in cervico-mediastinal thyroid masses admitted in our Clinic of Thoracic Surgery over a period of 22 years (1991-2012). METHODS: We reviewed 130 patients who underwent surgery for retrosternal thyroid masses, 77 (59.23%) women and 53(40.77%) men. Mean age was of 53 years. Shortness of breath was observed in 71 (54.61%) patients as the most frequent preoperative symptom. Cervico-thoracic CT scan reveales the existence of a cervico-mediastinal mass and can appreciate the degree of intrathoracic progression, tracheal compression and dislocation, as well as the relations with other anatomical structures of the visceral mediastinum. All 130 patients were prepared for a thoracic approach, majority of the cases were operated by Prof. T. Horvat. The surgical procedure was performed by cervical approach only in most of the cases (106 cases) (Kocher type cervicotomy in 63 cases and Horvat type "en-Y" cervicotomy in 43 cases). We used a bipolar approach for large cervico-thoracic masses: cervicotomy and partial upper sternotomy in 20 cases, cervicotomy and full sternotomy in 3 cases, cervicotomy and right axillary thoracotomy in one case. RESULTS: The removal of the thyroid mass and decompression of the trachea have been achieved in all cases. Post operative results were very satisfactory, with absence of respiratory distress and with normal function of the vocal cords. No post operative mortality was encountered. CONCLUSION: The presence of a cervico-mediastinal thyroid mass with or without respiratory distress requires a surgical excision as the only treatment option. The surgical procedure represented a milestone for both anesthesiologist (difficult intubation in some cases of large goiters) and thoracic surgeon.Thyroid masses extending to the mediastinum can be excised successfully by cervical incision. Bipolar approach has an excellent outcome, achieving a safe resection, especially in large thyroid masses extending to the mediastinum with close relations to mediastinal structures.

Hypertensive late hemothorax following left pneumonectomy.

INTRODUCTION: Lung cancer is an extremely serious disease, in most cases the onset of symptoms comes in late stages of the disease. Local and distant tumor development limits the surgical indication, many times the surgical act being a heroic one. Out of all pulmonary resections pneumonectomies are real challenges as possible postoperatory complications can be life-threatening. MATERIALS AND METHOD: We present the case of a 66 year-old female patient at the time of surgery, diagnosed with locally advanced adenocarcinoma of the left lung (lower lobe tumor invading the upper lobe), who sustained left pneumonectomy with mediastinal lymphadenectomy in March 2012. Immediate postoperative evolution was favorable" gradual reduction of the residual cavity, with left shift of the mediastinum€" basically a normal post-pneumonectomy course. RESULTS: Upon imagistic control at one year postoperatively the following was observed: the residual cavity had increased in size under the pressure of a fluid which instead of diminishing in quantity was present in a significantly higher volume than on previous postoperative examinations. The general consensus was that we are dealing with pleural metastases which were producing excess pleural fluid. The evolution of the patient and subsequent surgical interventions have demonstrated that the first impression is not always the truth. CONCLUSION: There are cases, like the one presented, which seem without therapeutic solution. Upon careful analysis, dubled by perseverance, these cases benefit from spectacular results which break down grim hypotheses previously formed. Associated pathology can create in these cases an unbalance in the organism, which will negatively influence local postoperative evolution.

Impact of adjuvant chemotherapy in stage IB non-small-cell lung cancer: an analysis of 112 consecutively treated patients.

PURPOSE: The impact of adjuvant chemotherapy (CT) in the management of radically resected stage IB non-small cell lung cancer (NSCLC) is highly debated. The aim of this study was to evaluate the outcome of this category of patients treated at our institution. METHODS: We retrospectively analysed the survival data of patients with pathologic stage IB NSCLC, who received at least 1 cycle of adjuvant CT. CT was planned to be platinum based and to be delivered for 6 cycles. RESULTS: One hundred and twelve consecutively treated patients were evaluated. PATIENT CHARACTERISTICS: median age 60 years, median tumor diameter 4 cm, 87% underwent lobectomy and 13% pneumonectomy, 58% had visceral pleural involvement (VPI). After a median follow up of 46 months, the estimated 5-year disease-free (DFS) and overall survival (OS) rates were 68% and 77%, respectively. The mean number of CT cycles was 5.2 (range 3-6), with 82% of patients receiving ≥ 5 cycles. The median cisplatin dose intensity (DI) was 22 mg/m(2)/week, and the relative DI was 85%. Median total cisplatin (CDDP) dose/patient was 416 mg/m(2). A total of 31 (27.6%) relapses were recorded, of which 81% were distant. Multivariate analysis showed no significant interaction between overall survival and the following variables: gender, type of surgery, histology, tumor volume, VPI. CONCLUSION: Our results compare favorably with the historical data evaluating the outcome of stage IB patients treated by surgery alone in a customary medical setting. Overall, our data support the use of adjuvant CT in stage IB NSCLC patients.

[Minimally invasive surgery in the treatment of malignant pleuro-pericardial effusions]. / Chirurgia miniinvaziva în tratamentul pleuro-pericarditelor maligne.

INTRODUCTION: Malignant pleuro-pericardial effusions (MPPEs) are a common problem in the treatment of patients with cancer and may occur with any malignancy. METHODS: Between 01.01.1998 -31.12.2008 we conducted a retrospective study. During this period of time 46 patients were diagnosed and treated for malignant pleuro-pericardial effusions in Clinic of Thoracic Surgery under Prof. Teodor Horvat coordination (from SUUMC). RESULTS: In this study a total of 42 MPPEs have been approached through minimally invasive procedures (36 patients underwent thoracoscopic procedures and 6 patients were subjected to VATS). In our study, the pulmonary cancers were the most frequent primary cancers who caused MPPEs (22 cases). The thoracoscopic pleuro-pericardial window was the most frequent and efficient procedure used for pericardial drainage (34 cases). Effective control of the recurent malignant pleural and pericardial effusions was made most frequent through postoperative pleural bleomycin instillation (22 cases) and through thoracoscopic insufflation of talc in 14 cases. CONCLUSIONS: The minimally invasive thoracic surgery is a safe and efficient method for diagnosis and treatment of pleuro-pericardial effusions.

[Hydatid cyst of anterior mediastinum]. / Chistul hidatic al mediastinului anterior.

INTRODUCTION: Echinococcosis is endemic in Romania. Hydatid cyst can develop in any segment or organ, but the most frequent locations are liver and lung. Mediastinal hydatid lesions are extremly rare and only a few cases exists in the medical literature. MATERIAL AND METHOD: Between 1994 and 2011 Thoracic Surgery Clinic, UMF "Carol Davila" there were 3 patients diagnosed and surgical trated for hydatid cyst of mediastinum. The patients were 2 men and 1 woman aged of 20, 37 and 52 years. All hydatid cysts were located in the anterior mediastinum and all were solitary lesions when diagnosed. RESULTS: In 1 case the positive diagnosis was made preoperatively, in the other 2 the diagnosis was intraoperative. The approach was through thoracotomy. One cyst was complicated (nonviable thymic hydatid cyst), treated by ideal cystectomy, and 2 cysts were viable. There was 1 postoperative complication: gaseous cerebral embolism remitted after medical treatment, caused by the intraoperative use of H2O2 as scolicide agent. CONCLUSIONS: Although very rare, anterior mediastinal hydatid cysts must be considered in every patient with anterior mediastinal mass. Complete surgical excision is the treatment of choice; surgery followed by parasiticide therapy provides complete cure.

[Neurogenic tumors of the posterior mediastinum]. / Tmorile neurogene ale mediastinului posterior.

The posterior mediastinum is the potential space along each side of the vertebral column and adjacent proximal portions of the ribs--the paravertebral sulci. From the posterior mediastinal tumors, the most commonly encountered are the neurogenic tumors (75%), the remaining 25% are represented by a heterogenous group of rare tumors including teratoma, lymphoma, sarcoma and other lesions arising outside the mediastinum and projecting into the posterior compartment. Surgical excision, by thoracotomy or miniinvasive techniques, is the first line of treatment in the posterior mediastinal tumors. Tumors with extension into the spinal canal (dumbbell tumors), accounting for nearly 10% of the posterior mediastinal tumors, require a multidisciplinary approach: thoracic surgeon and neurosurgeon. We present the experience of the "Carol Davila" University of Medicine and Pharmacy Thoracic Surgery Clinic in the surgery of neurogenic posterior mediastinal tumors throughout a 9 year period (2001 - 2010). 42 cases admitted and operated in this period are being analysed.

[Rapid serological diagnosis systems for human leptospirosis screening in Cuba]. / Sistemas serológicos rápidos utilizados para la pesquisa de leptospirosis humana en Cuba.

INTRODUCTION: human leptospirosis requires rapid and early microbiological diagnosis since it is a common lethal disease worldwide. OBJECTIVES: to increase the quality of microbiological diagnosis of this infection, to expand the knowledge on the circulation of groups of leptospiras in Cuba and to show the benefits of an agglutination assay using Cuban latex particles and of commercial immunochromatogenic systems LEPTO Dipstick, Lepto Tek Lateral Flow, Lepto Tek Dri Dot and SD Leptospira IgM-IgG. METHODS: this descriptive research used sera from positive and negative control cases to evaluate and measure the diagnostic value of rapid serological diagnosis systems with respect to the microagglutination method of reference (MAT). All the techniques used in this report are described in the Manual of Operations and Procedures of the Leptospira Lab in "Pedro Kourí" Institute of Tropical Medicine. RESULTS: all the studied diagnosis systems exhibited acceptable values of sensitivity, specificity and agreement when compared to the international microagglutination method of reference with live microorganisms. The great selectivity (antigen reactivity) and the diagnostic reliability of the diagnostic systems were confirmed; particularly the mixed Cuban-made latex, the LEPTO Dipstick and the SD Leptospira IgM-IgG. CONCLUSIONS: the procedures used in this research work exceeded the traditional methods including the microagglutination method of reference in terms of easiness, rapidity, technical simplicity and level of performance, and all were useful for the screening of antibodies to leptospiras.

[Solitary pulmonary nodule--150 resected cases]. / Nodulul pulmonar solitar--150 de cazuri operate.

Solitary pulmonary nodule represents a radiological entity with unknown prevalence in general population. As definition, solitary pulmonary nodule has 3 cm diameter or less and is surrounded by lung parenchyma, with no other abnormalities on the same chest X-ray or CT scan film. The differential diagnosis of the solitary pulmonary nodule includes over 100 conditions and the most frequent is lung cancer. Identification and correct management of the solitary pulmonary nodule opposes early detection and treatment of the lung cancer and the uselessness of a surgical procedure on a benign disease which needs no treatment. After analyzing 150 solitary pulmonary nodules resected and after comparing the results with the literature, given the fact that 48.66% of the nodules are malignant and 52.66% of the nodules have the maximum accepted dimensions (3 cm), the authors proposed an algorithm for solitary pulmonary nodule management adapted to Romania's accessibility to diagnostic procedures. As conclusion, the surgical resection of an indeterminate solitary pulmonary nodule (not certified as benign at CT scan or by biopsy) has an absolute indication and curative intention.

Right carinal pneumonectomy for a delayed diagnosis.

The authors present the case of a male patient misdiagnosed with right upper lobe tuberculosis and repeatedly treated for this in the last two years, without response. In our institution, the source of the hemoptysis proved to be a pulmonary carcinoma, which in its evolution involved the carina and the last tracheal ring. Right carenal pneumonectomy with two tracheal ring resection is performed, with reconstruction of the airway by anastomosing the main left bronchus to trachea. The resection involved also the azygos vein and the lateral wall of the superior vena cava (angioplastic resection), the vagus nerve and the pericardium, the last are being reconstructed with synthetic mesh. Histopatologic diagnosis is squamous cell carcinoma moderately differentiated. The right tracheal sleeve pneumonectomy was the therapeutically choice for a middle-aged patient with recurrent hemoptysis and retrostenotic lung destruction.

Isolectins from Solanum tuberosum with different detailed carbohydrate binding specificities: unexpected recognition of lactosylceramide by N-acetyllactosamine-binding lectins.

Glycosphingolipid recognition by two isolectins from Solanum tuberosum was compared by the chromatogram binding assay. One lectin (PL-I) was isolated from potato tubers by affinity chromatography, and identified by MALDI-TOF mass spectrometry as a homodimer with a subunit molecular mass of 63,000. The other (PL-II) was a commercial lectin, characterized as two homodimeric isolectins with subunit molecular masses of 52,000 and 55,000, respectively. Both lectins recognized N-acetyllactosamine-containing glycosphingolipids, but the fine details of their carbohydrate binding specificities differed. PL-II preferentially bound to glycosphingolipids with N-acetyllactosamine branches, as Galbeta4GlcNAcbeta6(Galbeta4GlcNAcbeta3)Galbeta4Glcbeta1C er. PL-I also recognized this glycosphingolipid, but bound equally well to the linear glycosphingolipid Galbeta4GlcNAcbeta3Galbeta4GlcNAcbeta3Galbeta4Glcbeta1Cer. Neolactotetraosylceramide and the B5 pentaglycosylceramide were also bound by PL-I, while other glycosphingolipids with only one N-acetyllactosamine unit were non-binding. Surprisingly, both lectins also bound to lactosylceramide, with an absolute requirement for sphingosine and non-hydroxy fatty acids. The inhibition of binding to both lactosylceramide and N-acetyllactosamine-containing glycosphingolipids by N-acetylchitotetraose suggests that lactosylceramide is also accomodated within the N-acetylchitotetraose/N-acetyllactosamine-binding sites of the lectins. Through docking of glycosphingolipids onto a three-dimensional model of the PL-I hevein binding domain, a Galbeta4GlcNAcbeta3Galbeta4 binding epitope was defined. Furthermore, direct involvement of the ceramide in the binding of lactosylceramide was suggested.

Inhibition of binding of lactoferrin to the human promonocyte cell line THP-1 by heparin: the role of cell surface sulphated molecules.

Lactoferrin, an iron-binding protein of the transferrin family, is a highly basic protein which interacts with many acidic molecules, including heparin proteoglycans. Such interactions may modify some of the biological properties of lactoferrin. In the present work we found that heparin caused a dose-dependent inhibition of specific binding of both human and bovine lactoferrin to human monocytic THP-1 cells. Low-affinity binding sites (Kd 500 nM) were more susceptible to inhibition by heparin than the high-affinity sites (Kd 100 nM). The effect was mediated by interaction between lactoferrin and heparin rather than by competition between heparin and lactoferrin for common binding sites on the cells. Pretreatment of cells with NaClO3 to prevent sulphation of surface glycosaminoglycans reduced lactoferrin binding, and de-N-sulphated heparin did not inhibit binding of lactoferrin to THP-1 cells. These results suggest that heparin binding and monocyte/macrophage binding by lactoferrin both involve interactions between basic regions in the N1 domain of lactoferrin and sulphate groups. The N-terminal Arg2-Arg5 sequence of human lactoferrin may be involved, but it does not seem to be the key element in these interactions.

[Recto-vesical and recto-vesico-vaginal fistulae caused by radiotherapy for carcinoma of the uterine cervix. Surgical treatment]. / Fistulele recto-vezicale si recto-vezico-vaginale postradice dupa neoplasm al colului uterin. Tratament chirurgical.

The authors present a study based on 4 cases of fistulous communication between the terminal digestive tube and the genitourinary tract, which appeared after surgery and radiation therapy for carcinoma of the uterine cervix. The diagnosis criteria (symptoms, clinical and imagistic findings), the objectives of the surgical treatment (external digestive derivation, treatment of the fistula and reconstruction of the digestive tube), the steps of the operation and the early and late postoperative evolution are pointed out. The conclusions are shown at the end.

[Gastrojejunocolic fistula after transmesocolic gastrojejunostomy for stenotic duodenal ulcer]. / Fistula gastro-jejuno-colica dupa gastro-jejunostomie transmezocolica pentru ulcer bulbar stenozant.

The authors are presenting the case of a 53 year-old patient, suffering from type II diabetes mellitus and ankylosing spondylitis, admitted in our clinic in July 1997 for gastrojejunocolic fistula, 5 years after a transmesocolic gastrojejunostomy for obstructive chronic duodenal ulcer. The severe metabolic disorders and the radiologic aspects which led to the diagnosis, as well as the morphopathologic lesions found and the ways to approach the fistula, the stenotic duodenal ulcer and the reconstruction of the digestive continuity in a single surgical procedure are further discussed. The conclusions are shown at the end.

Lactoferrin or a fragment thereof inhibits the endotoxin-induced interleukin-6 response in human monocytic cells.

Human milk is in several ways anti-inflammatory. This study investigates whether or not human milk lactoferrin (LF) in comparison with bovine LF can affect the IL-6 release from human cells. Human, as well as bovine, LF and a bactericidal pepsin-derived fragment of bovine LF (lactoferricin B) were found to suppress the IL-6 response in a monocytic cell line (THP-1) when stimulated by lipopolysaccharide (LPS). The suppression of bovine LF was similar to or higher than that of human LF. Lactoferricin B was the strongest inhibitor of the LPS-induced IL-6 response. A time-dependence regarding the inhibitory capacity of LF was found. For human LF, the strongest inhibition was observed when added 15-30 min after the addition of LPS. Addition of LF before the LPS induced an approximately 45% reduction of the IL-6 response. The results suggest an anti-inflammatory activity of both human and bovine LF, and of the LF fragment lactoferricin B through their suppressive effects on the cytokine release.

Lactoferrin-lipopolysaccharide interaction: involvement of the 28-34 loop region of human lactoferrin in the high-affinity binding to Escherichia coli 055B5 lipopolysaccharide.

The ability of lactoferrin (Lf), an iron-binding glycoprotein that is also called lactotransferrin, to bind lipopolysaccharide (LPS) may be relevant to some of its biological properties. A knowledge of the LPS-binding site on Lf may help to explain the mechanism of its involvement in host defence. Our report reveals the presence of two Escherichia coli 055B5 LPS-binding sites on human Lf (hLf): a high-affinity binding site (Kd 3.6 +/- 1 nM) and a low-affinity binding site (Kd 390 +/- 20 nM). Bovine Lf (bLf), which shares about 70% amino acid sequence identity with hLf, exhibits the same behaviour towards LPS. Like hLf, bLf also contains a low- and a high-affinity LPS-binding site. The Kd value (4.5 +/- 2 nM) corresponding to the high-affinity binding site is similar to that obtained for hLf. Different LPS-binding sites for human serum transferrin have been suggested, as this protein, which is known to bind bacterial endotoxin, produced only 12% inhibition of hLf-LPS interaction. Binding and competitive binding experiments performed with the N-tryptic fragment (residues 4-283), the C-tryptic fragment (residues 284-692) and the N2-glycopeptide (residues 91-255) isolated from hLf have demonstrated that the high-affinity binding site is located in the N-terminal domain I of hLf, and the low-affinity binding site is present in the C-terminal lobe. The inhibition of hLf-LPS interaction by a synthetic octadecapeptide corresponding to residues 20-37 of hLf and lactoferricin B (residues 17-41), a proteolytic fragment from bLf, revealed the importance of the 28-34 loop region of hLf and the homologous region of bLf for LPS binding. Direct evidence that this amino acid sequence is involved in the high-affinity binding to LPS was demonstrated by assays carried out with EGS-loop hLf, a recombinant hLf mutated at residues 28-34.

Immunoaffinity chromatography on antibodies immobilized on nitrocellulose powder.

A method is described for the use of nitrocellulose powder as a solid phase in a chromatographic procedure, for the immunoaffinity isolation of proteins. Two different immunoglobulins (Igs), anti-Datura innoxia lectin and anti-tyrosinase, were coupled to particulate nitrocellulose. A single step was then needed for purification to homogeneity of both D. innoxia lectin and mouse tyrosinase. Chaotropic and acidic agents proved to be effective in eluting antigens from Ig-nitrocellulose columns. The binding capacity of particulate nitrocellulose was around 3 mg Ig per milliliter of nitrocellulose, while the purification yields of the two proteins investigated under various eluting conditions were higher than 75%. The applicability of this method in the identification of metabolically labeled proteins in crude extracts is also demonstrated. Purification of proteins by affinity chromatography on their specific Igs linked to nitrocellulose matrices could be performed in both batch and column. The major advantages of this new method for purification of proteins are its rapidity, the reusability of the affinity matrices, and the high yields of purified protein obtained. The method could be seen as an alternative to the widely used immunoprecipitation technique.

Flow cytofluorimetric analysis of young and senescent human erythrocytes probed with lectins. Evidence that sialic acids control their life span.

Comparing the properties of 'young' and senescent ('aged') O+ erythrocytes isolated by applying ultracentrifugation in a self-forming Percoll gradient, we demonstrate that the sialic acids of membrane glycoconjugates control the life span of erythrocytes and that the desialylation of glycans is responsible for the clearance of the aged erythrocytes. This capture is mediated by a beta-galactolectin present in the membrane of macrophages. The evidence supporting these conclusions is as follows: (1) Analysis by flow cytofluorimetry of the binding of fluorescein isothiocyanate labelled lectins specific for sialic acids shows that the aged erythrocytes bind less WGA, LPA, SNA and MAA than young erythrocytes. The binding of DSA and LCA is not modified. On the contrary, the number of binding sites of UEA-I specific for O antigen and of AAA decreases significantly. PNA and GNA do not bind to erythrocytes. (2) RCA120 as well as Erythrina cristagalli and Erythrina corallodendron lectins specific for terminal beta-galactose residues lead to unexpected and unexplained results with a decrease in the number of lectin binding sites associated with increasing desialylation. (3) The glycoconjugates from the old erythrocytes incorporate more sialic acid than the young cells. This observation results from the determination of the rate of transfer by alpha-2,6-sialyltransferase of fluorescent or radioactive N-acetylneuraminic acid, using as donors CMP-9-fluoresceinyl-NeuAc and CMP-[14C]-NeuAc, respectively. (4) Microscopy shows that the old erythrocytes are captured preferentially by the macrophages relative to the young ones. Fixation of erythrocytes by the macrophage membrane is inhibited by lactose, thus demonstrating the involvement of a terminal beta-galactose specific macrophage lectin. (5) Comparative study of the binding of WGA, LPA, SNA and MAA to the aged erythrocytes and to the in vitro enzymatically desialylated erythrocytes shows that the desialylation rate of aged cells is low but sufficient to lead to their capture by the macrophages.