ABSTRACT
A kinetic study of the cells present in the spleen of BALB/c mice infected with Schistosoma mansoni was carried out. The lymphocytes were evaluated phenotypically with monoclonal antibodies and the effect of splenectomy on the modulation of periovular granuloma was also investigated. The infected mice had proportional increases in the numbers of neutophils, plasma cells, macrophages and eosinophils in the spleen. The largest number of neutrophil, plasma cells and macrophage were found between the 8th and the 12th week of infection, while the amount of eosinophils were higher later on, around the 20th week. The lymphocytes phenotipically characterized as Thy 1.2, Lyt 1.2 (CD4) increased mildly in proportional numbers. However, the percentage of lymphocytes with the Lyt 2.2 (CD8) phenotype, which is characteristic of supressor and cytotoxic T cells, increased significantly with the progress of the disease. The numbers of B lymphocytes, which comprise 50% of the mononuclear cells present in the spleen, increased significantly till the 16th week they began to decrease. The mean diameters of periovular granulomas were comparatively similar in both experimental groups (splenectomized and non-splenectomized mice). However, the evolutive types of granuloma (exudative, intermediate and fibrous) in splenectomized mice were proprtionally different from those of non splenectomized mice in the 16th and 24th week of infection. It is inferred that lymphonodes or other secondary lymphoide organs, in the abscence of the spleen, assume a modulating action on periovular granulomas, although the evolution of the granulomas is somehow delayed in splenectomized mice
Subject(s)
Rats , Animals , Antibodies, Monoclonal , Lymphocytes/analysis , Schistosoma mansoni/ultrastructure , SplenectomyABSTRACT
Foram processadas 62 amostras de sangue heparinizado, com a finalidade de se determinar valores de normalidade encontrados em nosso meio para a subpopulaçao linfocitaria T4 E T8, expressos em percentuais e em numeros absolutos. Estabeleceu-se tambem uma relaçao numerica entre T4/T8
Subject(s)
Humans , Adult , Middle Aged , Female , Male , Lymphocytes/analysis , T-Lymphocytes, Cytotoxic , T-Lymphocytes, Helper-InducerABSTRACT
Se estudiaron 43 pacientes con hepatitis crónica tipo B y AgeHB positivo, tratados con interferón alfa recombinante. A 21 de ellos se les realizó inmunosupresión previa con prednisona durante 2 semanas. Se evaluó su respuesta inmune celular mediante la cuantificación de subpoblaciones linfoides y los anticuerpos monoclonales T3 (CD3), T4 (CD4), T8 (CD8) antes y después del tratamiento. Se compararon estos resultados con los de un grupo control compuesto por 24 sujetos supuestamente sanos. Para la comparación se utilizó la prueba t de Student con un nivel de significación del 1 %. Hubo incremento de T4 en el grupo que recibió prednisona y disminución significativa de T8 en ambos grupos respecto al control, después del tratamiento, aunque sin diferencias entre los grupos de tratamiento. En el que respondió al tratamiento existía una disminución de T4 antes de iniciar la terapéutica lo cual serviría como factor pronóstico de la terapia antiviral de estos pacientes
Subject(s)
Adult , Humans , Male , Female , Hepatitis B/therapy , Interferon Type I/therapeutic use , Leukocyte Count , Lymphocytes/analysisABSTRACT
Se determinan los valores relativos de las células CD3+, CD4+ y CD8+ periféricas, los niveles de inmunocomplejos circulantes y las concentraciones séricas de las proteinas C3 y C4 del sistema de complemento en 27 pacientes con el objetivo de investigar la posible presencia de alteraciones inmunológicas en la retinosis pigmentaria. Se encontraron valores disminuidos de las células CD3+ y CD4+ en los pacientes, lo que se asocia con un índice CD4/CD8 bajo en relación con el grupo control. No se demostró la presencia de inmunocomplejos circulantes en ninguno de los enfermos. Las cifras séricas medias del C3 y C4 fueron inferiores a las de los controles. El descenso de las células CD4+ encargadas de inducir y cooperar en una respuesta inmune indica un defecto en los mecanismos de competencia inmunológica en la retinosis pigmentaria
Subject(s)
Adolescent , Adult , Middle Aged , Humans , Male , Female , Lymphocytes/classification , Retinitis Pigmentosa , Lymphocytes/analysisABSTRACT
Se determinan los valores relativos de las células CD3+, CD4+ y CD8+ periféricas, los niveles de inmunocomplejos circulantes y las concentraciones séricas de las proteinas C3 y C4 del sistema de complemento en 27 pacientes con el objetivo de investigar la posible presencia de alteraciones inmunológicas en la retinosis pigmentaria. Se encontraron valores disminuidos de las células CD3+ y CD4+ en los pacientes, lo que se asocia con un índice CD4/CD8 bajo en relación con el grupo control. No se demostró la presencia de inmunocomplejos circulantes en ninguno de los enfermos. Las cifras séricas medias del C3 y C4 fueron inferiores a las de los controles. El descenso de las células CD4+ encargadas de inducir y cooperar en una respuesta inmune indica un defecto en los mecanismos de competencia inmunológica en la retinosis pigmentaria
Subject(s)
Adolescent , Adult , Middle Aged , Humans , Male , Female , Retinitis Pigmentosa , Lymphocytes/classification , Lymphocytes/analysisABSTRACT
We have previously raised an anti-c-erb A peptide antibody (designated 4B II) which immunoprecipitated in vitro transcription/translation products of c-erb A alpha 1 and beta. 4B II could recognize nuclear T3 receptor (NT3R) without distinction between difference in species and tissues. Using 4B II, we studied immunohistochemical localization of NT3R proteins in various tissues of the rat. Cryostat sections (4-6 microns) of selected rat tissues were incubated with 4B II at 4C overnight, followed by fluorescein-isothyocianate-conjugated anti-rabbit immunoglobulin G for 60 min at 25 C. The cellular localization of fluorescence in all tissues examined was exclusively nuclear. Under the same conditions, control sections stained with antiserum which had previously absorbed with c-erb A peptide or inactive serum showed no specific staining. In the brain the large nuclei, supposed to be neuronal, were strongly stained in the cerebral cortex and the granular layer of the cerebellum. In the kidney, cells in the glomerulus, the distal, but not the proximal, tubules, and the collecting ducts exhibited nuclear staining. Nuclear fluorescence was observed homogeneously in the heart and liver, but the intensity was much weaker in the latter. Less intense fluorescence was seen in the testis and spleen, although specific immunostaining was clearly observed in the nuclei of spermatocytes, Leydig cells, and the heads of the sperms in the testis, and many lymphocytes in the spleen. Nuclei of follicular cells of the thyroid exhibited very strong fluorescence, suggesting existence of plenty of NT3R proteins. The anterior pituitary showed strong immunostaining in most nuclei, and clear nuclear fluorescence was also detected in the intermediate lobe of the pituitary. The present study showed that NT3R distributes selectively in certain types of cells in many tissues and that the content of NT3R proteins seems to correlate with the concentration of c-erb A mRNA alpha 1 and beta among many organs.
Subject(s)
Cell Nucleus/analysis , Proto-Oncogene Proteins/analysis , Receptors, Thyroid Hormone/analysis , Amino Acid Sequence , Animals , Brain Chemistry , Fluorescent Antibody Technique , Immune Sera , Immunohistochemistry , Kidney/analysis , Liver/analysis , Lymphocytes/analysis , Male , Molecular Sequence Data , Myocardium/analysis , Proto-Oncogene Proteins/immunology , Rats , Rats, Inbred Strains , Receptors, Thyroid Hormone/immunology , Spermatozoa/analysis , Spleen/analysisABSTRACT
The insulin receptor was immunoprecipitated from cultured human lymphocytes (IM-9) and rat hepatocytes (Fao) after biosynthetic labeling with [3H]glucosamine or [3H]mannose, and the nature of the carbohydrate units was investigated. Digestion of the receptor from IM-9 lymphocytes with E. freundii endo-beta-galactosidase increased the migration of the insulin receptor alpha- and beta-subunits on sodium dodecyl sulfate-polyacrylamide gels and sharpened the electrophoretic bands; the alpha-subunit was converted from an apparent mol wt (Mr) of 123,000 to a Mr of 118,000, and the beta-subunit from a Mr of 92,000 to 89,000. The susceptibility of the insulin receptor to this enzyme indicates that its carbohydrate units contain poly-N-acetyllactosamine sequences. Affinity chromatography of receptor glycopeptides on Concanavalin-A-Sepharose revealed that the poly-N-acetyllactosamine units were attached to multiantennary glycopeptides that accounted for over 75% of the [3H]glucosamine incorporated into the IM-9 lymphocyte insulin receptor; the remaining radioactivity was present in polymannose units (primarily Man8GlcNAc2) and biantennary complex saccharides. Several differences in the carbohydrate chains of the insulin receptor from the Fao and IM-9 cells indicated that glycosylation was cell specific despite the occurrence of poly-N-acetyllactosamine chains in both cell types. The IM-9 lymphocyte receptor glycopeptides were larger (Mr, 3,200-9,500) and more susceptible to endo-beta-galactosidase than those from the Fao receptor (Mr, 3,000-5,000). Moreover, the released saccharides from the Fao receptor were found by exoglycosidase digestions and chromatographic comparison to standards to contain terminal sialic acid in both alpha 2----3 and alpha 2----6 linkage to galactose, whereas the IM-9 carbohydrate units contained only alpha 2----3-linked sialic acid.
Subject(s)
Carbohydrates/analysis , Glycoside Hydrolases , Polysaccharides/analysis , Receptor, Insulin/analysis , Animals , Carbohydrate Conformation , Carbohydrate Sequence , Cell Line , Chromatography, Affinity , Glucosamine/metabolism , Glycosylation , Humans , Liver/analysis , Lymphocytes/analysis , Molecular Sequence Data , Molecular Weight , Oligosaccharides/analysis , Oligosaccharides/metabolism , Rats , Receptor, Insulin/metabolism , beta-Galactosidase/metabolismABSTRACT
Recent in vivo NMR studies have raised interest in the structural changes of cellular lipids during proliferative activity. We investigated the changes in plasma membrane lipid and total cell lipid during mitogenically-stimulated proliferation of human peripheral blood lymphocytes by extraction of lipids and assay by 500 MHz 1H-NMR. Resonances were assigned using one- and two-dimensional spectroscopic techniques, and signals unique to certain species of lipid were identified. Choline and ethanolamine-containing lipids, glycerophospholipid backbones, sphingolipids, cholesterol, plasmalogens and triacylglycerols were readily detected. Resolution of a number of lipid species was not possible, despite the use of high-resolution techniques. NMR values for proliferation-induced changes in the most easily determined parameters, namely the total cholesterol to total phospholipid molar ratio, and phosphatidylcholine, phosphatidylethanolamine and sphingolipid composition, were found to agree with traditional methods. Differences in phospholipid and fatty acid profiles were found between plasma membranes and total cell lipid for resting values and for response to mitogen.
Subject(s)
Lipids/analysis , Lymphocytes/analysis , Cell Membrane/analysis , Cells, Cultured , Cholesterol/analysis , Humans , Hydrogen , Lymphocyte Activation , Magnetic Resonance Spectroscopy , Membrane Lipids/analysis , Phospholipids/analysisABSTRACT
El intercambio de cromátides hermanas (ICH) (sensible indicador de mutágenos ambientales), el hemograma, la transaminasa glutámico oxalacética (TGO), la transaminasa glutámico pirúvica (TGP), la colinesterasa, los organoclorados y organofosforados en sangre periférica y el esperma, fueron estudiados en 44 individuos expuestos a plaguicidas y 36 controles no expuestos. El grupo de individuos expuestos estaba constituido por trabajadores agropecuarios en contacto directo o indirecto con los plaguicidas (organoclorados y organofosforados). Los estudios a este grupo se realizaron en 3 épocas distintas. Para cada una de las variables en consideración, se realizaron comparaciones expuestos y controles mediante el test "T" de Student. Se encontró significativo incremento en los eosinófilos y organoclorados, disminución en los glóbulos blancos del grupo expuesto con respecto al control; en el esperma se observaron alteraciones en la movilidad. En los ICH, niveles de TGO, de TGP, organoclorados y colinesterasa, no se detectaron diferencias significativas con respecto a los controles. Este trabajo es un enfoque global al problema y de ninguna manera pretende considerarse definitivo, se continuará profundizando en los diversos aspectos que lo constituyen. (AU)
Subject(s)
Humans , Male , Comparative Study , Sister Chromatid Exchange/drug effects , Spermatozoa/analysis , Pesticides/toxicity , Culture Techniques/methods , Lymphocytes/analysis , Occupational Exposure/adverse effects , Cholinesterases/blood , Insecticides, Organochlorine/toxicity , Insecticides, Organophosphate/toxicity , Erythrocyte Count , Leukocyte Count , Eosinophilia/blood , Occupational Diseases , Surveys and Questionnaires , ResearchABSTRACT
El intercambio de cromátides hermanas (ICH) (sensible indicador de mutágenos ambientales), el hemograma, la transaminasa glutámico oxalacética (TGO), la transaminasa glutámico pirúvica (TGP), la colinesterasa, los organoclorados y organofosforados en sangre periférica y el esperma, fueron estudiados en 44 individuos expuestos a plaguicidas y 36 controles no expuestos. El grupo de individuos expuestos estaba constituido por trabajadores agropecuarios en contacto directo o indirecto con los plaguicidas (organoclorados y organofosforados). Los estudios a este grupo se realizaron en 3 épocas distintas. Para cada una de las variables en consideración, se realizaron comparaciones expuestos y controles mediante el test "T" de Student. Se encontró significativo incremento en los eosinófilos y organoclorados, disminución en los glóbulos blancos del grupo expuesto con respecto al control; en el esperma se observaron alteraciones en la movilidad. En los ICH, niveles de TGO, de TGP, organoclorados y colinesterasa, no se detectaron diferencias significativas con respecto a los controles. Este trabajo es un enfoque global al problema y de ninguna manera pretende considerarse definitivo, se continuará profundizando en los diversos aspectos que lo constituyen.
Subject(s)
Humans , Male , Sister Chromatid Exchange , Pesticides/toxicity , Spermatozoa/analysis , Cholinesterases/blood , Culture Techniques , Eosinophilia/blood , Erythrocyte Count , Occupational Exposure/adverse effects , Insecticides, Organochlorine/toxicity , Insecticides, Organophosphate/toxicity , Leukocyte Count , Lymphocytes/analysis , Occupational Diseases , Research , Surveys and QuestionnairesABSTRACT
A expressäo dos genes ribossômicos representada pelas freqüências de associaçöes de satélites e de regiöes organizadoras de nucléolo (RONs) ativas foi avaliada em culturas de linfócitos de um grupo de recém-nascidos e um grupo de indivíduos com idades entre 70-90 anos, através de técnica de coloraçäo pela prata. Observamos freqüências semelhantes de RONs ativas em ambos os grupos ao lado de uma freqüência mais elevada de associaçöes de satélites no grupo dos idosos
Subject(s)
Infant, Newborn , Aged , Humans , Male , Female , Chromosomes, Human/physiology , Lymphocytes/analysis , Nucleolus Organizer Region/physiology , Aged, 80 and over , SilverSubject(s)
G(M1) Ganglioside , Gerbillinae/immunology , Glycosphingolipids/analysis , Lymphocytes/analysis , Spleen/cytology , Animals , Cytotoxicity Tests, Immunologic , Glycosphingolipids/immunology , Killer Cells, Natural/immunology , Lymphocytes/immunology , Male , Mice , Mice, Inbred BALB C , Mice, Inbred ICR , Microscopy, ElectronABSTRACT
To examine the role of DNA methylation in breakpoint location of chromosomal translocation, HpaII sites in and flanking the M-bcr on chromosome 22 were mapped in DNA from blood granulocytes and lymphocytes, bone marrow cells, thymic tissue, and spermatozoa from normal individuals. Allelic HpaII sites were identified clustered in a 600-base pair genomic area of the M-bcr. Bone marrow cells and blood granulocyte DNA showed identical allelic patterns. Thymic tissue and blood lymphocytes showed identical allelic patterns distinct from bone marrow cells and blood granulocytes. Spermatozoa showed a third methylation pattern. In all individuals, the HpaII sites were present within the BamHI/BglII fragment of the M-bcr, the same area associated with high breakpoint frequency in chronic myelogenous leukemia (CML). Three of 15 patients with chronic phase CML showed fully methylated rearranged BglII/BglII M-bcr restriction fragments not seen in normal bone marrow cells. These methylation patterns of the M-bcr may be important in CML breakpoint location and may be a marker for tissue differentiation.
Subject(s)
DNA/genetics , Leukocytes/analysis , Blotting, Southern , DNA/blood , DNA/isolation & purification , Granulocytes/analysis , Humans , Leukemia, Myeloid, Acute/blood , Leukemia, Myeloid, Acute/genetics , Lymphocytes/analysis , Methylation , Nucleic Acid Hybridization , Reference Values , Restriction MappingABSTRACT
The clinicopathologic features of 15 patients with mixed gonadal dysgenesis are presented with special regard to cardiovascular and neoplastic disease. Seven (47%) cases, all phenotypic females, had gonadal tumors: gonadoblastoma (5), germinoma (4), malignant intratubular germ cell neoplasia (1), and a unique gonadal stromal tumor (1). Gonadoblastoma was found in 4 of 10 testes and 4 of 17 streak gonads, and associated with germinoma in 4 cases. One patient developed grade 1 endometrial adenocarcinoma after estrogen therapy. Cardiovascular diseases (ie, bicuspid aortic valve, and a unique right aortic arch with a retroesophageal arch segment, aberrant left subclavian artery, coarctation, and dissection) are documented in our series. At the time of diagnosis of mixed gonadal dysgenesis, removal of streak gonads or testes will prevent further gonadal tumor development Cardiovascular examination may identify treatable and potentially lethal disease.
Subject(s)
Adenocarcinoma/pathology , Aorta, Thoracic/abnormalities , Gonadal Dysgenesis, Mixed/pathology , Gonadal Dysgenesis/pathology , Neoplasms, Germ Cell and Embryonal/pathology , Testicular Neoplasms/pathology , Uterine Neoplasms/pathology , Adenocarcinoma/metabolism , Adolescent , Adult , Aortic Diseases/pathology , Child , Female , Gonadal Dysgenesis, Mixed/metabolism , Humans , Immunohistochemistry , Karyotyping , Lymphocytes/analysis , Male , Neoplasms, Germ Cell and Embryonal/metabolism , Testicular Neoplasms/metabolism , Uterine Neoplasms/metabolismABSTRACT
There is disagreement about the existence of permanent single-strand breaks in the nuclear DNA of quiescent lymphocytes, possibly due to different experimental approaches. Using the nucleoid sedimentation technique, no evidence is found for spontaneous DNA single-strand breakage in unstimulated human lymphocytes and for quick break-sealing after mitogenic stimulation. An increased sedimentation rate of nucleoids, which can be monitored as soon as 3 h after stimulation, is shown to be due rather to an additional long-range folding of nuclear DNA. Such temporal folding appears to be related to RNA transcription and may interfere with detection of DNA single-strand breakage.
Subject(s)
DNA , Lymphocyte Activation , Lymphocytes/analysis , Centrifugation, Density Gradient , DNA, Single-Stranded , DNA, Superhelical , Humans , Lymphocytes/metabolism , Nucleic Acid Conformation , Transcription, GeneticABSTRACT
We tested the hypothesis that lymphocytes from swine with susceptibility to malignant hyperthermia (MH) had calcium extrusion activity higher than unaffected swine. Cytoplasmic concentration of ionized calicum was determined by use of dual emission spectrofluorometry and measurement of the ratio of free to calcium-bound form of the fluorescent calcium dye indo-1. Net calcium accumulation and unidirectional calcium extrusion rate were dependent on intracellular calcium concentration. Calcium extrusion from calcium-loaded lymphocytes was monitored while calcium influx was inhibited by suspending the cells in calcium-free medium with a calcium chelator. Net calcium accumulation of untreated lymphocytes was monitored in calcium-replete medium. A novel method of calculation of ionized calcium was used. This method confirmed our previous findings of lower ionized calcium concentration (86 +/- 40 and 370 +/- 216 nmol/L; P less than 0.01) and slower rates of calcium accumulation 39 +/- 16 and 127 +/- 52 nmol/L/min) in untreated lymphocytes from MH-susceptible swine compared with controls. These changes were attributable to calcium extrusion activity two- to three-fold higher in lymphocytes of MH-susceptible swine (154 +/- 36 and 408 +/- 47 nmol/L/min at 175 nmol/L; 972 +/- 111 and 1,690 +/- 505 nmol/L/min at 425 nmol/L). These data were compatible with our model of higher calcium extrusion activity being a compensatory adaptation of MH-susceptible swine lymphocytes to their hypersensitivity to stimuli that increase cytoplasmic calcium concentration.
Subject(s)
Calcium/metabolism , Lymphocytes/metabolism , Malignant Hyperthermia/veterinary , Swine Diseases/blood , Animals , Caffeine/pharmacology , Calcium/blood , Disease Susceptibility , Halothane/pharmacology , Lymphocytes/analysis , Malignant Hyperthermia/blood , Muscle Contraction/drug effects , SwineABSTRACT
This study shows that microscopic image analyses of nuclear DNA have common characteristics among fixation methods and tissue types. We find that microscopic imaging measurements require both nuclear area and DNA concentration to properly convey diagnostic information. Algorithms are developed which enable infiltrating lymphocytes to act as internal DNA controls for each sample. The DNA content and patterns measured by microscopic imaging were found to be related to patient survival and to cytologic diagnosis.
Subject(s)
Cell Nucleus/analysis , DNA, Neoplasm/ultrastructure , Image Processing, Computer-Assisted , Microscopy/methods , Nasopharyngeal Neoplasms/genetics , Algorithms , Humans , Lymphocytes/analysis , Nasopharyngeal Neoplasms/mortality , Ploidies , Survival AnalysisABSTRACT
To date, analysis of the DNA content of head and neck squamous cell carcinomas has relied on the homogenation of the entire tissue specimen and subsequent staining and quantitation of the naked nuclei. This methodology does not make allowance for the extremely variable nature of these tumors with respect to their cellular composition. Further, by destroying the cytoplasm and cell membranes, this methodology makes it impossible to distinguish the DNA content of the tumor cells from that of the background stromal and inflammatory cells. The authors present a methodology for the selective exclusion of inflammatory cell infiltrates from the DNA analysis of these tumors. Using this technique, it has been found that exclusion of the inflammatory cells allows the investigator to look more specifically at the malignant cell population. This has been most helpful in those samples in which the tumor cells have been diploid or near-diploid. With this technical refinement, the relationship between DNA ploidy and clinical prognosis may be more accurately assessed.
Subject(s)
Carcinoma, Squamous Cell/analysis , DNA, Neoplasm/analysis , Flow Cytometry/methods , Head and Neck Neoplasms/analysis , Aged , Female , Humans , Leukocyte Count , Leukocytes/analysis , Lymphocytes/analysis , Male , Middle AgedABSTRACT
We have conducted investigations on members of three families with increased predisposition to cancer which appears to be inherited as an autosomal dominant trait. The aim of our studies overall is to provide markers for the mutant genes involved, so that gene carriers may be monitored closely for signs of malignant disease. This paper reports on studies of chromosome breakage in lymphocytes from affected and at-risk family members and control subjects. No increase in spontaneous chromosome breakage was observed in family members compared with controls. An increased sensitivity to chromosome damage induced by the alkylating agent, N-methyl-N1-nitro-N-nitrosoguanidine (MNNG), was observed in three members from two families; one person was affected, the others at risk. These families included cases of osteosarcoma, in addition to various types of cancer of epithelial origin. Two members (one affected, one at-risk) of a third family showed increased sensitivity to the radio-mimetic agent, bleomycin. This family appeared to represent the cancer family syndrome. Whilst not conclusive at present, our results appear to justify investigation of members of cancer families with respect to sensitivity to chromosome breaking agents.
Subject(s)
Chromosome Aberrations/genetics , Lymphocytes/analysis , Neoplastic Syndromes, Hereditary/genetics , Adult , Bleomycin/adverse effects , Disease Susceptibility , Female , Genes, Dominant , Genetic Carrier Screening , Genetic Markers , Humans , Male , Methylnitronitrosoguanidine/adverse effects , Middle Aged , Neoplastic Syndromes, Hereditary/blood , Neoplastic Syndromes, Hereditary/chemically induced , PedigreeABSTRACT
To clarify a mechanism of insulin resistance associated with myotonic dystrophy, we studied the insulin receptor by using three different types of cells--circulating erythrocytes, cultured skin fibroblasts, and Epstein-Barr virus(EBV)-transformed lymphocytes. In myotonic dystrophy, insulin binding to erythrocytes and fibroblasts was significantly decreased as a result of a reduction of the binding affinity. Insulin binding to EBV-transformed lymphocytes was normal. When the receptors were purified from fibroblasts with wheat germ agglutinin, we could not find a decrease in the binding affinity seen in the intact cells. No difference was observed in the magnitude of basal and insulin-stimulated autophosphorylation of insulin receptors from EBV-transformed lymphocytes between the control and myotonic dystrophy. Southern blot analysis of the insulin receptor gene revealed no restriction fragment length polymorphism associated with myotonic dystrophy. These findings suggest that there is no primary defect of the insulin receptor per se in terms of insulin binding and autophosphorylation in myotonic dystrophy. The reduction of the insulin binding to erythrocytes and fibroblasts may be caused by the plasma membrane abnormality that affects the binding affinity of the receptor.