RESUMO
The hepatoprotective action of Silymarin was studied in 65 male Wistar rats, prior to and following D-galactosamine intoxication. There was a marked reduction in the histological and ultrastructural changes in the nucleolus, nuclear membrane, mitochondria, granular and agranular endoplasmic reticulum and lysosomes of the liver cell and also in the Kupffer stellate cells. The reduction in glycogen and RNA loss was determined biochemically. The activities of many enzymes were kept constant (oxidoreductases, NADH2 diaphorase, G-6-phosphatase, Mg++ and K+/Na+-dependent ATPases, acid phosphatases).
Assuntos
Doença Hepática Induzida por Substâncias e Drogas/prevenção & controle , Flavonoides/uso terapêutico , Galactosamina , Silimarina/uso terapêutico , Fosfatase Ácida/metabolismo , Adenosina Trifosfatases/metabolismo , Animais , Membrana Celular/enzimologia , Avaliação de Medicamentos , Glucose-6-Fosfatase/metabolismo , Fígado/ultraestrutura , Glicogênio Hepático/análise , Masculino , Mitocôndrias Hepáticas/enzimologia , Ácidos Nucleicos/análise , Oxirredutases/metabolismo , RatosRESUMO
Our work analyses the effects of radiotherapy in cervical carcinoma by computerized morphometry techniques that evaluate the morphologic changes in the specimens taken from pre and post-irradiation biopsies of 8 cases. These cases were diagnosed as squamous cell carcinoma, undifferentiated (1 case), moderately (5 cases) and well differentiated (2 cases). For each case, 40 relevant microscopic fields were chosen, reflecting the morphologic aspects before (20 fields) and after irradiation (20 fields). The digitised images of these fields were used for measuring the tumoral and stromal areas by a program we implemented in the Zeiss KS400 environment. The program provides a mean tumoral/stromal area for each case, computed by averaging the results of the 20 measurements performed on the pre and post-irradiation images. In terms of a stereological interpretation, each mean tumoral area expresses the percentage of the tumoral volume and can be used as an index for quantifying the efficiency of the radiotherapy. Such an index allows developing comparative discussions on cases that belong either to the same diagnosis entity, or to different diagnosis entities. These discussions yield the idea that the morphologic classification of a case is not sufficient to accurately predict the efficiency of irradiation, and a systematic approach to the morphometric features, before and after irradiation, may contribute to the refinement of the prediction.
Assuntos
Algoritmos , Carcinoma de Células Escamosas/patologia , Processamento de Imagem Assistida por Computador , Neoplasias do Colo do Útero/patologia , Carcinoma de Células Escamosas/diagnóstico , Carcinoma de Células Escamosas/radioterapia , Feminino , Humanos , Células Estromais/patologia , Células Estromais/efeitos da radiação , Neoplasias do Colo do Útero/diagnóstico , Neoplasias do Colo do Útero/radioterapiaRESUMO
UNLABELLED: High levels of high-density lipoprotein cholesterol (HDL) are associated with a reduced risk of cardiovascular disease, so that many studies focus on modify HDL levels for therapeutic purpose. AIM: The present research aims to highlight changes in plasma levels of HDL-cholesterol in experimental animals with a high-fat diet associated with some branched aminoacids--valine and leucine. MATERIAL AND METHODS: The experiment was realised on 32 male Wistar rats, which were divided in four groups: group I--received a standard diet; group II--was fed with cholesterol (C), group III (C + V)--cholesterol and valine and group IV (C + L)--cholesterol and leucine. After 8 weeks animals were evaluated in relation with lipids levels in the blood. RESULTS: The average values of HDL-cholesterol in group who received only cholesterol (C) were significantly lower compared with group III who received cholesterol and valine (C + V) or group IV that received cholesterol and leucine (C + L) (p < 0.001), after one month and at the end of the experiment. CONCLUSIONS: Our results showed that valine and leucine increased the serum levels of HDL-cholesterol and therefore they are useful components in coronary artery disease risk reduction. The association of these aminoacids in human diets can improve clinical conditions associated with hyperlipidaemia such as atherosclerosis.
Assuntos
Aminoácidos de Cadeia Ramificada/administração & dosagem , HDL-Colesterol/sangue , HDL-Colesterol/efeitos dos fármacos , Dieta Hiperlipídica , Hipercolesterolemia/sangue , Hipercolesterolemia/terapia , Algoritmos , Animais , Doenças Cardiovasculares/prevenção & controle , Dieta , Modelos Animais de Doenças , Leucina/administração & dosagem , Masculino , Ratos , Ratos Wistar , Valina/administração & dosagemRESUMO
UNLABELLED: Inflammation of the vascular wall is an essential event in the development of atherosclerosis, the main leukocytes of the inflammatory infiltrate being the monocyte/macrophages. These cells are very heterogeneous and rapidly change their function in response to signals received from the local environment. PURPOSE: The aim of this research was to study the immunohistochemical expression of the anti-CD68 antibody at the level of the atherosclerotic plaque. MATERIALS AND METHODS: We used tissue samples obtained by endarterectomies in patients with symptomatic atherosclerotic lesions. Inflammatory reaction was highlighted in the arterial wall by immunohistochemistry using an anti-CD68 monoclonal antibody that marks normal or pathological monocytes/macrophages. RESULTS AND DISCUSSION: The types of analyzed atherosclerotic lesions showed a positive reaction with the anti-CD68 antibody, varying in distribution and intensity in the vascular intima. The CD68 was positive in macrophages depending on the extent of the inflammatory reaction. CONCLUSIONS: The presence of many macrophages in the atherosclerotic plaques indicates a chronic inflammatory reaction, accompanied by fibroblast proliferation and connective tissue changes that influence the stability of the plaques.
Assuntos
Antígenos CD/biossíntese , Antígenos de Diferenciação Mielomonocítica/biossíntese , Regulação da Expressão Gênica , Imuno-Histoquímica/métodos , Placa Aterosclerótica/patologia , Túnica Íntima/patologia , Adulto , Idoso , Anticorpos Monoclonais/química , Aterosclerose/metabolismo , Aterosclerose/patologia , Proliferação de Células , Endarterectomia/métodos , Fibroblastos/citologia , Humanos , Macrófagos/citologia , Pessoa de Meia-Idade , Placa Aterosclerótica/metabolismo , Estudos RetrospectivosRESUMO
UNLABELLED: Endometrial hyperplasia is a proliferation of the endometrium with increased number of glands and the change of the gland-stroma ratio. By histopathologic examination is now accepted the WHO classification. Atypical hyperplasia is accepted to be a precursor for endometrioid carcinoma. In order to find some prognostic elements, immunohistochemical reactivity of hormone receptors and markers in endometrial hyperplasia, was performed. MATERIAL AND METHODS: From 162 cases of EH, 32 cases were selected for immunohistochemical investigations. Avidin-biotin-peroxidase method was used for revealing estrogen and progesterone receptors (ER, PGR) and Ki-67 and EGF factors. RESULTS: The immune reactivity for ER and PGR increase in parallel with the complexity of glandular morphological changes. Ki-67 demonstrated a strong immune reactivity together with EGF in atypical hyperplasias. CONCLUSIONS: The diagnosis of EH can be made by histopathological examinations. The immunohistochemistry aids for the prognosis, in order to establish the best treatment.
Assuntos
Biomarcadores Tumorais/metabolismo , Carcinoma Endometrioide/diagnóstico , Hiperplasia Endometrial/diagnóstico , Neoplasias do Endométrio/diagnóstico , Receptores de Estrogênio/metabolismo , Receptores de Progesterona/metabolismo , Carcinoma Endometrioide/metabolismo , Hiperplasia Endometrial/metabolismo , Neoplasias do Endométrio/metabolismo , Fator de Crescimento Epidérmico/metabolismo , Feminino , Humanos , Imuno-Histoquímica/métodos , Antígeno Ki-67/metabolismo , PrognósticoRESUMO
UNLABELLED: Hypercholesterolemia plays an important role in atherosclerosis. The dietary supplementation of proteins or specific aminoacids seems to enhance the immune status in animals and humans with a complex pathological status, decreasing morbidity and mortality. AIM: In the present study we intended to analyse the effects of some nonpolar aminoacids--valine and leucine on cholesterol blood levels in a high-fat-diet in rats. In the same time we evaluated the vascular walls impact produced by the hypercholesterolemic diet. MATERIAL AND METHODS: Our experiment was realised on 32 male Wistar rats, which were fed with cholesterol, valine and leucine for 8 weeks. At the end of experiment we analysed serum levels of cholesterol and also histopathological features of hypercholesterolemia on the arterial wall. CONCLUSION: The results of our study indicate that valine and leucine decrease the serum cholesterol and therefore the hypercholesterolemic-induced prooxidant status of the body being useful in reducing atherosclerosis.
Assuntos
Colesterol na Dieta , Colesterol/sangue , Endotélio Vascular/efeitos dos fármacos , Hipercolesterolemia/dietoterapia , Hipercolesterolemia/etiologia , Leucina/farmacologia , Valina/farmacologia , Aminoácidos de Cadeia Ramificada/farmacologia , Animais , Artérias/efeitos dos fármacos , Aterosclerose/dietoterapia , Aterosclerose/etiologia , Biomarcadores/sangue , Modelos Animais de Doenças , Hipercolesterolemia/sangue , Hipercolesterolemia/complicações , Hipercolesterolemia/prevenção & controle , Leucina/administração & dosagem , Masculino , Estresse Oxidativo/efeitos dos fármacos , Ratos , Ratos Wistar , Valina/administração & dosagemRESUMO
UNLABELLED: The microcirculation in neuropathic diabetic feet is the subject of the same changes found in other end organs of the diabetic patients. In diabetic neuropathy, abnormal neurogenic regulation of the hemodynamics in the small vessels may contribute to the development of microangiopathy, which is manifested as increased basement thickening. MATERIAL AND METHODS: The study has been made on a group of 25 patients: nine with diabetes mellitus type 1 and 16 patients with diabetes mellitus type 2. All patients were affected by peripheral diabetic neuropathy and showed various degrees of lesions on the foot level. All cases required amputations done at the lower extremity of the limbs. Tissue fragments were processed for the standard histopathological exam, using Hemalaun-Eosin, trichromic Szekely and van Gieson staining. RESULTS: The histopathological examination revealed on the skin level--ulcerations covering large areas, while entire sections showed hyperacanthosis. At the dermis level, the microscopic panel was dominated by the presence of the inflammatory infiltrate. The absence or the degeneration of the sweat glands, the presence of venous stasis and perivascular bleedings completed the morphological panel of the dermis. On the microcirculation level, the endothelial cells have a flat smooth inflated aspect. In the case of the large arterioles and arteries of muscular type, we observed the presence of the fibrous tissue on the level of media, calcium deposits on intima, mediocalcinosis. CONCLUSIONS: The identification of vascular and nervous morphological structures in the complicated diabetic foot allows the extension of the knowledge related to the pathological background of this condition. The vascular lesions, which appeared on the microcirculation level, are consequently involving arterioles and arteries of muscular type and are being accompanied by nervous lesions shown through morphological changes of the peripheral nerves. The overall morphological contest of the complicated diabetic foot involves lesions of the epidermis, dermis, and muscles.
Assuntos
Angiopatias Diabéticas/complicações , Angiopatias Diabéticas/patologia , Pé Diabético/complicações , Pé Diabético/patologia , Neuropatias Diabéticas/complicações , Neuropatias Diabéticas/patologia , Epiderme/patologia , Feminino , Humanos , Inflamação/complicações , Inflamação/patologia , Masculino , Necrose , Nervos Periféricos/patologia , Trombose/complicações , Trombose/patologiaAssuntos
Fosfatase Ácida/análise , Adenosina Trifosfatases/análise , Intoxicação por Tetracloreto de Carbono/enzimologia , Esterases/análise , Glucose-6-Fosfatase/análise , Fígado/enzimologia , Monoaminoxidase/análise , Succinato Desidrogenase/análise , Animais , Feminino , Fluorescência , Histocitoquímica , Masculino , Ratos , Coloração e RotulagemAssuntos
Ductos Biliares Intra-Hepáticos/enzimologia , Colestase/metabolismo , Fígado Gorduroso/metabolismo , Fosfatase Ácida/análise , Adenosina Trifosfatases/análise , Fosfatase Alcalina/análise , Animais , Ductos Biliares Intra-Hepáticos/patologia , Complexo IV da Cadeia de Transporte de Elétrons/análise , Feminino , Glucose-6-Fosfatase/análise , Histocitoquímica , Hidroxibutirato Desidrogenase/análise , L-Lactato Desidrogenase/análise , Masculino , Monoaminoxidase/análise , Oxirredutases/análise , CoelhosRESUMO
UNLABELLED: The aim of this study was to demonstrate the bony structural changes in deep periodontal pockets. MATERIAL AND METHODS: Bony fragments were taken from the alveolar wall of a group of 24 patients diagnosed with deep periodontal lesions which required the extraction of certain irrecuperable teeth. Fragments were fixed in glutaraldehyde, then decalcified in EDTA 5% and proccesed for electron microscopic examination and a semifinesse sections to microscop "Zeiss Axioscop". RESULTS: Both optic and electron microscopy showed: decreaze of bone mineralization and alterations in cholagen structure; the presence of osteoclasts with intense activity and numerous macrofages; at the level of bone marrow, small, insignificant inflammatory reactions, contrasting with the important surrounding modifications; in certain cases though osteolytic reactions occured, the osteoclasts could not by evidenced, on the contrary, numerous macrophages with intense lysosomal enzymes activity were noticed; all the cases showed an alteration of the alveolar bone cholagen. CONCLUSION: Thus, we can better understand the role of primary factors in this bony structures.
Assuntos
Perda do Osso Alveolar/patologia , Osteoclastos/patologia , Bolsa Periodontal/patologia , Idoso , Perda do Osso Alveolar/cirurgia , Biópsia , Feminino , Humanos , Inflamação/patologia , Masculino , Microscopia Eletrônica/métodos , Pessoa de Meia-Idade , Doenças Periodontais/patologia , Doenças Periodontais/cirurgia , Bolsa Periodontal/cirurgiaRESUMO
UNLABELLED: Capillarisation of hepatic sinusoids is a well recognized phenomenon occurring in chronic hepatitis as well as in hepatocellular carcinoma. MATERIAL AND METHODS: Tissue sections were obtained by liver biopsy from 35 patients with different degrees of chronic hepatitis. The specimens were fixed in formalin and embedded in paraffin and an immunohistochemical investigation was performed by the standard avidin-biotin-peroxidase complex method with CD34. RESULTS: The sinusoids of normal liver showed no immunoreactivity. CD34 (+) staining was present in portal vessels and only in periportal areas in chronic hepatitis with mild activity. In cases with severe chronic hepatitis CD34 (+) staining was important in portal areas and with focal distribution on sinusoid endothelial cells. CONCLUSIONS: The results indicate that the expression of CD34 by sinusoidal endothelial cells may reflect the phenotypic change of endothelial cells in chronic hepatitis and CD34 can be used as endothelial marker to evaluate the sinusoid lesions.
Assuntos
Antígenos CD34/análise , Veias Hepáticas/química , Hepatite Crônica/metabolismo , Antígenos CD34/imunologia , Biomarcadores/análise , Biópsia , Progressão da Doença , Células Endoteliais/química , Endotélio Vascular/química , Veias Hepáticas/patologia , Hepatite Crônica/patologia , Hepatite Crônica/virologia , Humanos , Imuno-Histoquímica/métodos , Índice de Gravidade de DoençaRESUMO
UNLABELLED: Endometrial hyperplasias are now diagnosed according to the histopathological examination. By using immunohistochemistry, the authors search for supplementary elements for the diagnosis and evaluation of the prognosis of this nosologic framework. MATERIAL AND METHODS: We investigated a number of 138 cases of endometrial hyperplasia, using immunohistochemical research. The avidine-biotin-peroxidase method revealed estrogenic and progesterone receptors, together with EGF, proliferative Ki67 and cyclin D1. RESULTS: The reaction was positive in variable percents for estrogenic receptors, especially for complex atypical hyperplasias. A positive immunoreactivity was also found for progesterone receptors and for Ki67 (in atypical hyperplasias); cyclin D1 revealed only a moderate reaction. CONCLUSIONS: Immunohistochemistry can be useful for the prognosis of the lesion, but it is not indispensable for diagnosis, while the histopathologic examination is absolutely necessary for a complete endometrial hyperplasia diagnosis.
Assuntos
Hiperplasia Endometrial/diagnóstico , Biomarcadores Tumorais/metabolismo , Ciclina D1/metabolismo , Hiperplasia Endometrial/metabolismo , Fator de Crescimento Epidérmico , Feminino , Humanos , Imuno-Histoquímica/métodos , Antígeno Ki-67/metabolismo , Prognóstico , Receptores de Estrogênio/metabolismo , Receptores de Progesterona/metabolismoRESUMO
UNLABELLED: The endometrium has a few possibilities to express the underlying pathology, even if there may be a potential dangerous one. This study is searching for a relationship between the ultrasound images of endometrial hyperplasias and the respective pathologic exams. MATERIAL AND METHOD: We analyzed 385 cases of endometrial hyperplasias hospitalized in the "Elena Doamna" Maternity from Iasi, Romania during the period 2000-2005. RESULTS: For all the cases included, the endometrium had a width from 2 mm to 20 mm, with a median of 9mm. The hyperplasias were: 70.18% simple hyperplasias without atypia, 18.52% complex hyperplasias without atypia, 7.1% complex hyperplasias with atypia and 4.17% secretory hyperplasias. There were no differences between the aspects or thickness of the endometrium in regard with any of the types of hyperplasias. CONCLUSIONS: Ultrasounds exams have a limited role to diagnose endometrial hyperplasias. They only selects patients for mandatory other investigations. Key words:
Assuntos
Hiperplasia Endometrial/diagnóstico por imagem , Hiperplasia Endometrial/patologia , Hiperplasia Endometrial/diagnóstico , Endométrio/diagnóstico por imagem , Endométrio/patologia , Feminino , Humanos , Valor Preditivo dos Testes , Estudos Retrospectivos , Sensibilidade e Especificidade , Ultrassonografia Doppler em Cores/métodosRESUMO
Liver sinusoids are irregularly dilated capillaries. The sinusoidal lining consists of a sample squamous epithelium. Endothelial cells constitute the major cellular element of the sinusoidal lining and form a discontinuous endothelium. These cells are separated by gaps 0.1-0.5 mm wide. The endothelial cells also show numerous intracellular pores or fenestrations. They perform important filtration function due to the presence of small fenestrations that allow free diffusion of many substances and show huge endocytic capacity. Liver sinusoidal endothelial cells may function as antigen-presenting cells (APC) and are also active in the secretion of cytokines, eicosanoids, endothelin-1, nitric oxide and some extracellular matrix components. They can store and metabolize substances as serum immunoglobulins, too.
Assuntos
Capilares/citologia , Células Endoteliais/ultraestrutura , Fígado/irrigação sanguínea , Capilares/ultraestrutura , Células Endoteliais/fisiologia , Humanos , Microscopia EletrônicaRESUMO
Twenty three cases of parotid gland pleomorphic adenoma from Surgical Oro-Maxillo Facial Clinic of "Sf. Spiridon" Hospital, Iasi, have been evaluated. In order to reveal the particular microscopic aspects, several histological techniques have been used: HE, Van Gieson, PAS, Alcian Blue and Gordon Sweet. The microscopic evidences points out the variety of microscopic forms even within the same case, and also the prevalence of some particular forms such as myo-epithelial cell predominance, squamous metaplasia and cystic degeneration. Our observations, corroborated with the one from other research, support the hypothesis of an unique ectodermal cell origin for the lesion histogenesis.
Assuntos
Adenoma Pleomorfo/patologia , Neoplasias Parotídeas/patologia , Adenoma Pleomorfo/ultraestrutura , Humanos , Microscopia , Glândula Parótida/patologia , Neoplasias Parotídeas/ultraestrutura , Estudos RetrospectivosRESUMO
Adenosquamous carcinomas range between 5-25% of cervical cancers and are composed by an admixture of malignant squamous and glandular elements. The aim of our study was to identify some common characteristics and to evaluate the correlation between the degrees of differentiation of the two components. We analyzed 15 cases diagnosed in a 6 years period. The age ranged between 26 years and 67 years (mean age 46.5 years). Paraffin embedding, followed by HE staining were performed. Differential diagnosis with endometrioid adenocarcinoma of the cervix with squamous metaplasia was made. Four cases (26.66%) were subtyped as clear cell adenosquamous carcinomas and 2 cases (13.33%) were subtyped as glassy cell carcinomas, exhibiting finely granular ground glass type cytoplasm. 93.33% of cases exhibited a poorly differentiated squamous component and 66.66% of cases exhibited a well differentiated glandular component. 20% (3 cases) presented prominent lymphoplasmacytic and eosinophilic inflammatory tumoral infiltrate. Squamous intraepithelial lesions in overlying epithelium was observed in 4 cases (26.66%). One case presented extension to the uterine body. One case, diagnosed as glassy cell subtype, presented regional lymph node metastases. Our study concluded the occurrence of adenosquamous cervical carcinomas at a similar age with squamous cervical carcinomas in the investigated group of patients. As adenosquamous cervical carcinomas are considered expressions of a biphasic differentiation of a single pluripotential sub-columnar reserve cell, a similar degree of differentiation of the two components would be expected. Although, we registered a degree of variability in grading of the two components, with a tendency of squamous component toward poorly differentiated aspect and a slightly dominant aspect of well differentiated glandular pattern.
Assuntos
Carcinoma Adenoescamoso/patologia , Neoplasias do Colo do Útero/patologia , Adulto , Idoso , Carcinoma Adenoescamoso/diagnóstico , Diagnóstico Diferencial , Feminino , Humanos , Pessoa de Meia-Idade , Estudos Retrospectivos , Neoplasias do Colo do Útero/diagnósticoRESUMO
Tumor adenosis represents a rare lesion, which most frequent appears as a palpable mass, with more than the usual dimensions. The paper presents a case of tumor adenosis of the mammary gland of a 16 years girl. Macroscopically, the tumor was well delimited, with gray-white surface and a nodular aspect on section. The tissue was processed by routine technique and stained with hematoxylin-eosine (H&E). There were also performed immunohistochemical (Actin SM, CK, S100) and special stainings (silver impregnation). Microscopically, there were observed several histologic types of adenosis, the most frequent being sclerosing adenosis. Through silver impregnation it was observed that the basement membrane, which surrounded the tubes, was intact. Immunohistochemically, there were evidentiated the epithelial and myoepithelial components of the tubes. The presence of these elements led through the diagnosis of tumor adenosis. The importance of recognition of the tumor adenosis is found in the possibility of wrong interpretation of this with tubular invasive carcinoma, these two entities being often mistaken, mainly at the frozen-section examination.
Assuntos
Doença da Mama Fibrocística/patologia , Adenocarcinoma/patologia , Adolescente , Neoplasias da Mama/patologia , Diagnóstico Diferencial , Feminino , Humanos , Imuno-Histoquímica , Coloração pela PrataRESUMO
Ito cells (the fat-storing cells) are stellate cells located in the space of Disse. They can be selectively stained with gold chloride, but their distinguishing feature in routine histological preparations is the presence of multiple lipid droplets in their cytoplasm. Ito cells have the capacity to accumulate exogenously administered vitamin A as retinyl esters in lipid droplets. The quantity of vitamin A, which is stuck into Ito cells, decreases progressively in liver injury, like chronic alcohol intake. Also, the fat-storing cells are the principal cellular source of collagen and other extracellular substances in normal as well as fibrotic liver. Liver injury is followed by an increase in the number of the fat-storing cells.
Assuntos
Adipócitos/citologia , Fígado/citologia , Vitamina A/análise , Adipócitos/metabolismo , Humanos , Imuno-Histoquímica , Fígado/metabolismo , Hepatopatias/metabolismo , Hepatopatias/patologia , Microscopia EletrônicaRESUMO
The pathomorphogenesis of renal lesions in the course of cirrhogenic diseases of the liver was studied on a human and experimental material. The development of membranoproliferative glomerulopathy, of tubular lesions, interstitial reactive infiltrates and sclerosis processes in the advanced stages of cirrhosis were observed. An important role in the determining of these lesions was played by immunologic perturbations in the entire organism.
Assuntos
Rim/patologia , Cirrose Hepática/patologia , Adolescente , Adulto , Animais , Membrana Basal/patologia , Capilares/patologia , Intoxicação por Tetracloreto de Carbono/patologia , Doença Hepática Induzida por Substâncias e Drogas/patologia , Criança , Humanos , Glomérulos Renais/patologia , RatosRESUMO
Changes in the fine structure of the lymph nodes were studied after prolonged immunization with heterologous sera. Hypertrophy of the lymph node cortex and paracortex frequently occurred, as well as development of the zone lying next to the lymphatic sinuses, postcapillary venules, veins and arteries in the cortex, paracortex and medulla, which is mainly bursa-dependent. Worthy of note was the presence of germinative centers characterized by large ribosomes, rich cells and macrophages. Similar aspects were observed in splenectomized animals undergoing prolonged immunization. Particular aspects of immunologic activity in the lymph nodes were noticed in the animals which had received an immunosuppressive treatment during immunization. The significance of the morphological alterations in the fine structure of the lymph nodes is correlated with the serological findings.