GDP-fucose uptake into the Golgi apparatus during xyloglucan biosynthesis requires the activity of a transporter-like protein other than the UDP-glucose transporter.

The molecular mechanisms regulating hemicelluloses and pectin biosynthesis are poorly understood. An important question in this regard is how glycosyltransferases are oriented in the Golgi cisternae, and how nucleotide sugars are made available for the synthesis of the polymers. Here we show that the branching enzyme xyloglucan alpha,1-2 fucosyltransferase (XG-FucTase) from growing pea (Pisum sativum) epicotyls was latent and protected against proteolytic inactivation on intact, right-side-in pea stem Golgi vesicles. Moreover, much of the XG-FucTase activity was membrane associated. These data indicate that XG-FucTase is a membrane-bound luminal enzyme. GDP-Fuc uptake studies demonstrated that GDP-Fuc was taken up into Golgi vesicles in a protein-mediated process, and that this uptake was not competed by UDP-Glc, suggesting that a specific GDP-Fuc transporter is involved in xyloglucan biosynthesis. Once in the lumen, Fuc was transferred onto endogenous acceptors, including xyloglucan. GDPase activity was detected in the lumen of the vesicles, suggesting than the GDP produced upon transfer of Fuc was hydrolyzed to GMP and inorganic phosphate. We suggest than the GDP-Fuc transporter and GDPase may be regulators of xyloglucan fucosylation in the Golgi apparatus from pea epicotyls.

Xyloglucan fucosyltransferase, an enzyme involved in plant cell wall biosynthesis.

Cell walls are crucial for development, signal transduction, and disease resistance in plants. Cell walls are made of cellulose, hemicelluloses, and pectins. Xyloglucan (XG), the principal load-bearing hemicellulose of dicotyledonous plants, has a terminal fucosyl residue. A 60-kilodalton fucosyltransferase (FTase) that adds this residue was purified from pea epicotyls. Peptide sequence information from the pea FTase allowed the cloning of a homologous gene, AtFT1, from Arabidopsis. Antibodies raised against recombinant AtFTase immunoprecipitate FTase enzyme activity from solubilized Arabidopsis membrane proteins, and AtFT1 expressed in mammalian COS cells results in the presence of XG FTase activity in these cells.

[Mycetomas caused by Microsporum canis. Report of one case]. / Micetomas por Microsporum canis. Caso clínico.

We report an eight years old boy presenting with a pyogenic granuloma of the scalp, generalized alopecia, descamative plates in the neck, trunk and limbs and nail involvement. Cultures for fungus of all these lesions disclosed Microspore canis. The patient was treated with oral griseofulvin, miconazole and topical tolnaftate. Five years later and after several incomplete treatments, the patient returns with a fistulous mass of 15 x 8 cm in the dorsal area whose culture revealed Microspore canis. The mass was excised and oral ketoconazole was indicated. After three months of follow up, the patient was lost from control.

Topography and Function of Golgi Uridine-5[prime]-Diphosphatase from Pea Stems.

Golgi UDPase is an enzyme that has been shown to function in polysaccharide biosynthesis, but its role in this process is not yet clear. In this study we identified Golgi UDPase activity in pea (Pisum sativum) stems and differentiated it from another UDPase activity. We demonstrated that Golgi UDPase is an integral membrane protein, based on specific partitioning of this activity into Triton X-114. Analysis of its topology using sealed, right-side-out Golgi vesicles and treatment with proteinase K suggested that its active site faces the Golgi lumen. Studies aimed at understanding the function of Golgi UDPase by incubating Golgi vesicles with [beta]-32P]UDP-glucose (Glc) to generate [beta]-32P]UDP upon Glc transfer in situ showed that 32Pi, but not [beta]-32P]UDP, was formed, suggesting that UDPase quickly hydrolyzed the UDP formed during Glc polymerization. We found that the Golgi UDPase was highly active in the elongating region of the third internode, whereas no activity was detected in the first and second internodes of etiolated pea seedlings. These results suggest that UDPase removes the UDP formed during Glc polymerization and could be important in the mechanism of polysaccharide biosynthesis.

Evidence for a UDP-Glucose Transporter in Golgi Apparatus-Derived Vesicles from Pea and Its Possible Role in Polysaccharide Biosynthesis.

The Golgi apparatus in plant cells is involved in hemicellulose and pectin biosynthesis. While it is known that glucan synthase I is responsible for the formation of [beta]-l-4-linked glucose (Glc) polymers and uses UDP-Glc as a substrate, very little is known about the topography of reactions leading to the biosynthesis of polysaccharides in this organelle. We isolated from pea (Pisum sativum) stems a fraction highly enriched in Golgi apparatus-derived vesicles that are sealed and have the same topographical orientation that the membranes have in vivo. Using these vesicles and UDP-Glc, we reconstituted polysaccharide biosynthesis in vitro and found evidence for a luminal location of the active site of glucan synthase I. In addition, we identified a UDP-Glc transport activity, which is likely to be involved in supplying substrate for glucan synthase I. We found that UDP-Glc transport is protein mediated. Moreover, our results suggest that UDP-Glc transport is coupled to the exit of a luminal uridine-containing nucleotide via an antiporter mechanism. We suggest that UDP-Glc is transported into the lumen of Golgi and that Glc is transferred to a polysaccharide chain, whereas the nucleotide moiety leaves the vesicle by an antiporter mechanism.

[Usefulness of immunocytochemistry in the identification of Mallory bodies. Theoretical analysis about their formation]. / Utilidad de la inmunocitoquímica en la identificación de cuerpos de Mallory. Análisis teórico de su formación.

BACKGROUND: Mallory bodies are hepatocyte intracytoplasmic inclusions frequently observed in liver diseases. They contain altered intermediary filaments that have immunoreactivity with epidermic antikeratin antibodies (A-QEp). They also contain ubiquitin (Ubq) a 76 residue polypeptide that has an important role in the proteolysis of rapid exchange and abnormal cytosol proteins. AIM: To standardize an immunohistochemical method for the detection of Mallory bodies in percutaneous liver biopsies. METHODS: A-QEP and A-Ubq polyclonal antibodies were used in the study of 131 percutaneous liver biopsies obtained from patients with different liver diseases. Mallory body immunoreactivity was confirmed with immunoelectron microscopy. RESULTS: Mallory bodies had scanty immunostaining with A-QEp, specially in formalin fixed biopsies. There was a specific and sensitive staining with A-Uhq, that was not influenced by the fixation method. Immunoelectron microscopy demonstrated that Mallory bodies are partially formed by altered intermediate filaments. CONCLUSIONS: Antibodies against ubiquitin may be very useful for the detection of Mallory bodies in liver biopsies.

Reprogramming of nucleolar gene expression during the acclimatization of the carp.

During seasonal acclimatization of eurythermal fish, the nucleolus of the hepatocyte undergoes ultrastructural reprogramming. In winter acclimatized carp, the nucleolar components are segregated, a condition that suggests a decreased transcription of rRNA. The same nucleolar reorganization was observed when pituitary cells from winter- and summer-acclimatized carp were examined. In situ analyses of nucleolar RNA revealed a marked lowering of RNA content in the segregated nucleoli. Accordingly, in vitro synthesis of RNA was shown to be significantly lower in pituitary tissue from cold-acclimatized fish where precursor accumulated. Conversely, in pituitary tissue from summer-adapted fish the rate and extent of synthesis and of rRNA processing was notably higher. The involvement of pre-rRNA processing events during seasonal acclimatization was corroborated by the strong differences of U3 RNA content detected by in situ hybridization in pituitary cells from summer- and winter-fish. When RNA polymerase I activity from both acclimatized states were assayed, no differences were detected. Thus, it appears that in fish RNA polymerase I itself does not play an important role in the control of nucleolar gene expression and the nucleolar gene expression reprogramming that the seasonal rearrangement represents might involve, among the many nucleolar-specific proteins, transcription factors.

Presencia de condensaciones pericanaliculares inmunogénicamente semejantes a cuerpos de Mallory en colestasia / Presence of perinacular condensations immunogenicaly similar to Mallory's bodies in cholestasia

El rol del citoesqueleto del hepatocito en secreción biliar y en la génesis de colestasia ha sido estudiado especialmente en relación a microfilamentos y microtúbulos, restándosele importancia los filamentos intermedios (FI). En cambio, estudios recientes han demostrado que la integridad de los FI del hepatocito es fundamental en la secreción biliar. Los FI del hepatocito corresponden a citoqueratinas y en ciertas patologías, especialmente de etiología alcohólica, éstos se alteran y en algunas ocasiones forman agregados como los cuerpos de Mallory (CM) cambiando sus características antigénicas. Se estudiaron 131 biopsias hepáticas con técnicas inmunohistoquímicas, utilizando sueros anti-queratinas epidérmicas y anti-ubiquitina, polipéptido de función proteolítica de proteínas anormales. De las biopsias estudiadas, 47 por ciento presentaban signos de colestasia y de éstas, un 64 por ciento presentó inmunorreacción en condensaciones pericanulares con anti-ubiquitina y un porcentaje algo menor con anti-queratinas; el resto de las biopsias fueron negativas con ambos anticuerpos. Estas observaciones indican que en biopsias hepáticas con signos de colestasia, las condensaciones pericaniculares correspondían a FI alterados, con características inmunogénicas semejantes a CM

Caso clínico: adenocarcinoma mesonefroide de la uretra femenina / Clinic case: mesonephroide adenocarcinoma of the female urethra

Se presenta un caso de adenocarcinoma mesonefroide de la uretra en un paciente de 63 años, tratada con exanteración pelviana anterior logrando una sobrevida de tres años. Se destaca la rareza de este tumor y se revisa la literatura

Experimental autoimmune thyroiditis. II. An immunocytochemical and ultrastructural study of the lesion.

The early steps of thyroid damage in experimentally induced autoimmune thyroiditis in mice were studied. Mice were immunized with 150 micrograms of rat thyroglobulin followed by 20 micrograms of bacterial LPS 3 h later on day 0 and 7. Thyroid glands were obtained on days 14, 21 and 28 in order to be studied by light microscopy, electron microscopy and immunocytochemical techniques. The initial lesion was a focal inflammatory infiltrate composed of lymphocytes and lymphoblasts, and plasma cells as the damage progressed. In some cases an increase in neutrophils, macrophages and eosinophils was also seen. The infiltrate became multifocal and eventually diffuse and in few cases germinal center-like structures were seen. The cellular infiltrate corresponded to IgG, IgM and IgA bearing B cells and to a lesser degree Thy 1.2, Lyt 1 and Lyt 2 bearing T cells. Follicular alterations corresponded to different degenerative states of the follicular cells that in some cases was seen without the participation of lymphoid cells. Another mechanism observed was the migration of small lymphoid cells and plasma cells between the follicular cells.

[Shortened preoperative preparation in diffuse hyperthyroid goiter: experience in 34 patients]. / Preparación preoperatoria abreviada en los bocios difusos hipertiroídeos. Experiencia en 34 pacientes.

Conventional preparation of goitrous hyperthyroid patients using lugol and propranolol may take 2 weeks. This period may be shortened using sodium iopodate and dexamethasone. We used 500 mg of sodium iopodate and 1 mg dexamethasone for 4 days in 34 hyperthyroid patients. Surgical indication derived from failure to medical treatment (68%), large goiter (27%) or adverse reaction to PTU (6%). Clinical euthyroidism was achieved after 4 days in all patients. T3 levels decreased from 482 +/- 26.2 to 137.6 +/- 3.7 ng/dl and T4 from 20.6 +/- 1.04 to 15.2 +/- 0.5 micrograms/dl (p < 0.005). Surgery was uneventful in 33 patients, one subject developed supraventricular tachycardia responsive to verapamil. Electron microscopy of the removed thyroid tissue revealed marked decrease of superficial villi and large phagosomes. Thus, sodium iopodate and dexamethasone are effective and safe for preoperative preparation of hyperthyroid patients.

[Pathologic fracture of the femur due to primary hyperparathyroidism]. / Fractura patológica de femur debida a hiperparatiroidismo primario.

Pathologic fractures are not commonly described in primary hyperparathyroidism. A 31 year old male with primary hyperparathyroidism developed severe hypercalcemia and cystic osteitis. Bone pains and a fracture of the femur followed. A parathyroid adenoma was demonstrated by ultrasonography. After resection of the tumor, a normalization of serum Ca levels and clinical recovery took place.

Experimental autoimmune thyroiditis. I. Participation of IgA, IgM and IgG in the development of the disease.

Many factors have been shown to be important in the pathogenesis of experimentally induced autoimmune thyroiditis (EAT) in mice. However, the role of thyroid antibodies has not been clearly established. EAT was induced with rat Tg + LPS in RK mice. Two injections were given i.v. on days 0 and 7 and the antibody titre against rat and syngeneic Tg was determined in the weeks thereafter. Determination of the cellular infiltration of the thyroid, the presence of IgA, IgG and IgM in thyroid sections and electron microscope analysis of electro-dense deposits were also undertaken. Results show that (1) RTg + LPS is a potent inducer of autoimmunity with high antibody titer to RTg and MTg and 100% of the mice showed some degree of thyroid infiltrate on days 21 and 28; (2) immunofluorescence staining revealed that initially IgM is the main immunoglobulin and is later replaced by IgG. IgA is constantly present throughout the experimental period; (3) electro-dense deposits were found almost exclusively between the capillary basement membrane and the follicular basement membrane.

[Medullary carcinoma of the thyroid. Clinical case]. / Carcinoma medular de tiroides. Caso clinico.

A 13 year old girl presented with a thyroid nodule and enlarged cervical lymph nodes. Symptoms endocrine dysfunction were absent. The patient was submitted to complete thyroidectomy and modified cervical lymph node dissection. Diagnosis of medullary carcinoma was confirmed through both optical and electron microscopy. At 30 months of follow up no evidence of local or distant recurrence was observed.