Ca++-dependent disassembly and reassembly of occluding junctions in guinea pig pancreatic acinar cells. Effect of drugs.

Incubation of guinea pig pancreatic lobules in Ca++-free Krebs-Ringer bicarbonate solution (KRB) containing 0.5 mM ethylene glycol-bis(beta-aminoethyl ether)N,N,N',N'-tetraacetate (EGTA) results in the progressive fragmentation of the occluding zonulae (ZO) with formation of multiple discrete junctions (fasciae occludentes) localized in the lateral and lumenal plasmalemma. After 1--2 h of such incubation, most ZO appear completely disassembled. This results in the disappearance of the heterogeneity in density of intramembrane particles on the P-fracture faces of the basolateral and lumenal plasmalemma. If Ca++ ions are reintroduced into the incubation fluid at this point, continous zonulae reform around the apices of the cells; in contrast, the density of intramembrane particles (imp) at the lumenal plasmalemma remains the same as in the basolateral region, at least for 3 h after Ca++ reintroduction. When added to the incubation fluid, cycloheximide (at a dose known to inhibit protein synthesis greater than 95%) and cytochalasin B (at doses which disrupt microfilaments and modify the cell shape) had no effect on the organization of ZO, on their disassembly in Ca++-free, EGTA medium, or on their Ca++-dependent reformation. Likewise, the organization and disassembly of ZO were unaffected by colchicine; however, after treatment with the latter drug the reassembly was defective, with formation of strand networks on the lateral surface and incomplete segregation of the lumenal region. Antimycin A, on the other hand, when added to the Ca++-EGTA medium, induced a large proliferation of long, infrequently anastomosed junctional strands, usually arranged to form ribbons, festoons, and other bizarre arrays. The possible relationship of these in vitro findings to the in vivo biogenesis and turnover of occluding junctions is discussed. It is suggested that the impairment of reassembly of zonulae by colchicine might be correlated with the disorder induced by the drug on the general organization of pancreatic exocrine cells. Moreover, antimycin A could act by promoting the aggregation of a pool of free junctional strand components (or precursors) that might exist normally in pancreatic exocrine cells.

Effect of medullary tonicity on urinary sodium excretion in the rat.

In previous reports from this laboratory we have suggested that a reduction in medullary tonicity decreases the thin ascending loop of Henle sodium reabsorption and is in part responsible for the magnitude for the natriuresis accompanying 10% body weight Ringer loading. According to this postulate, one would expect that the medullary washout associated with water diuresis would also result in a natriuresis, but this does not occur. It is possible, however, that increased delivery from the proximal tubule is necessary to demonstrate an effect of medullary tonicity on urinary sodium excretion. Micropuncture studies were designed to test that possibility by increasing distal delivery by 2% Ringer loading in animals with and without reduced medullary tonicity. In an initial series of experiments the alpha-adrenergic agonist clonidine was used to induce a water diuresis. When given alone, this agent caused a marked decrease in urine osmolality and an increase in urine flow rate but had no effect on proximal reabsorption in either superficial or juxtamedullary nephrons, and did not alter urinary sodium excretion. Volume expansion with 2% body weight Ringer solution resulted in a significant fall in proximal reabsorption and a trivial increment in sodium excretion. When this same degree of volume expansion was conferred on animals undergoing a water diuresis, a marked increase in absolute and fractional sodium excretion occurred. In a second group of studies medullary tonicity was reduced in the left kidney only by removal of the left ureter 1 h before micropuncture. When these animals were infused with 2% body weight Ringer solution, proximal reabsorption was decreased in juxtamedullary nephrons, and a marked increase in sodium excretion was observed only from the left kidney. Finally, the effect of water diuresis on fractional sodium delivery to the early and late distal tubule of superficial nephrons during 2% Ringer loading was evaluated. Delivery to both of these sites was comparable after 2% Ringer loading alone and during 2% Ringer loading plus water diuresis. From these data, we conclude that medullary tonicity does influence renal sodium handling but that this effect is manifest in the final urine only under conditions in which proximal reabsorption is decreased. The data also suggest that this effect is limited to juxtamedullary nephrons and is probably localized to the thin ascending limb of the loop of Henle.

Decrease of CD4+CD45+ T-cells in chronic-progressive multiple sclerosis.

Circulating lymphocyte subpopulations defined by anti-CD45 and other more common T-cell-specific monoclonal antibodies were analysed in 77 patients with multiple sclerosis and 38 healthy controls. A selective decrease of CD4+CD45+ cell percentages and absolute numbers in chronic-progressive patients was found; in 13 out of 26 patients this subpopulation was less than 11% CD4+CD45+ cells. Similarly, the whole CD45+ cell subset, as well as CD45+ cells expressed as percentages of CD4+ cells, were significantly reduced in chronic-progressive multiple sclerosis. CD4+CD45+ cells, commonly termed "inducer of suppression" T-lymphocytes, did not correlate with percentages or numbers of CD8+ cells. It is concluded that suppressor inducer T-cells act on the CD8+ subset function rather than reducing CD8+ cell numbers. Since CD4+CD45+ cells represent an early stage of lymphocyte maturation (naive T-cells), an under-representation of this subpopulation in active multiple sclerosis might reflect an increased conversion of naive cells into memory cells. This concept may be relevant for a better understanding of the disease pathogenesis.

Clinical utility of fractionating erythrocytes into "Percoll" density gradients.

Two rapid methods for fractionating the RBC into five or nine layers of increasing density are reported. These procedures have been used to monitor the decline of glucose-6-phosphate dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD) activity during the process of red cell aging in normal subjects and in beta-thal carriers, to study transfused patients with G6PD and pyruvate kinase (PK) deficiency and to test the effects of inositol hexaphosphate (IHP) encapsulation on RBC subpopulations.

Status de vitamina d y marcadores de metabolismo óseo en diabetes gestacional

RESUMEN Introducción y objetivos: La deficiencia de vitamina D (VD) ha sido asociada con alteración del metabolismo glucémico y síndrome metabólico. Datos actuales sugieren que tendría un rol en la prevención de diabetes gestacional y pre eclampsia. El presente estudio fue diseñado para evaluar los niveles de vitamina D en embarazadas con diabetes mellitus gestacional (DMG) y su relación con los niveles de fructosamina, parathormona, marcadores del metabolismo óseo y control metabólico. Materiales y métodos: Se incluyeron 44 embarazadas con diagnóstico de DMG, entre 15 y 45 años de edad. Las variables analíticas que se determinaron fueron: fructosamina, 25- hidroxivitamina D (25-OH-VD), Parathormona (PTH), calcio total, calcio iónico, fosforo y calcio corregido por albúmina. Resultados: Se analizaron los niveles de 25-OH-VD según las estaciones del año. El valor promedio fue de 37 ng/ml en verano, 26 ng/ml en otoño, 24 ng/ml en primavera y 17 ng/ml en invierno. Se evidenció una relación inversa entre VD y PTH (p<0.014). La correlación entre VD e índice de masa corporal (IMC) revelo un valor promedio de VD de 32.27 ng/ml en grupo con IMC <30 versus 23.63 ng/ml en el grupo con IMC >30 (p<0.027). Se observó relación inversa entre VD y fructosamina (p 0,479). Conclusión: La prevalencia de deficiencia de VD durante el embarazo debe ponerse a consideración en vista de las potenciales implicancias clínicas sobre la salud materna, fetal y postnatal, especialmente cuando se asocia a otros factores de riesgo como sobrepeso, obesidad y diabetes mellitus gestacional.

ABSTRACT Introduction and objectives: Vitamin D deficiency has been associated with altered glycemic metabolism and metabolic syndrome. New data suggest that it might have a role in prevention of gestational diabetes mellitus and preeclampsia. The present study was designed to analyze the relationship between vitamin D with parathormone levels, bone turn over markers and metabolic control. Methodology: The sample consisted of 44 pregnant women with gestational diabetes mellitus, ages 15-45, who attended to endocrinology external consultation. The variables analyzed were 25-hydroxivitan D, parathormone, fructosamine, total calcium, ionic calcium, calcium corrected by albumin and phosphorus, also, the relationship with body mass index, season of the year and age. Results: 25-hydroxivitamin D levels were analyzed regarding the season of the year; the average value was 37 ng/ml in summer, 26 ng/ml in autumn, 24 ng/ml in spring and 17 ng/ml in winter. There was an inverse relationship between vitamin D and parathormone (p<0.014). The analysis regarding vitamin D and BMI revealed the following values, 32.27 ng/ml for BMI <30 and 23.63 ng/ml for BMI >30 (p<0.027). There was an inverse relationship between Vitamin D and fructosamine (p 0.479). Conclusions: The prevalence of Vitamin D deficiency during pregnancy must be taken into account because of the implications in multiple aspects of maternal, fetal and postnatal health, especially when it is associated with other risk factors as overweight, obesity and gestational diabetes mellitus.

Informe de la CABE-FASEN: Monitoreo de desórdenes por defciencia de iodo (DDI) en la provincia de Santa Fe, Argentina (2007) / CABE-FASEN Report: Screening of Disorders Associated with lodine Defciency in the Province of Santa Fe, Argentina (2007)

Un total de 1.470 alumnos de escolaridad primaria, de ambos sexos, fue estudiado en este monitoreo de bocio endémico en cuatro localidades de la provincia de Santa Fe: Reconquista (n=404) y Villa Ocampo (n=294) ubicadas en el norte de la provincia, y Rufino (n=317) y Venado Tuerto (n=455) ubicadas en el sur provincial. La edad de los escolares osciló entre 6 y 14 años. Se examinó el cuello de todos los escolares; con el fin de aunar criterios con los realizados en otras provincias, se tomó como referencia la palpación de un solo médico (HN). La definición del grado de bocio fue la misma que fuera utilizada en los otros relevamientos. Se determinó la ioduria en muestras casuales de orina emitidas por los niños una vez que fueron palpados (109 de Reconquista, 105 de Villa Ocampo, 113 de Rufino y 139 de Venado Tuerto). Se midió también el contenido de iodo en 337 muestras de sal de consumo hogareño de Reconquista, 227 de Villa Ocampo, 295 de Rufino y 422 de Venado Tuerto (traídas por los niños desde sus viviendas). El examen palpatorio de los niños reveló una prevalencia de bocio del 2,6%, sin diferencias por localidad. Los niveles de ioduria mostraron diferencias entre las localidades del norte y del sur: en Reconquista 238,6±116 µg/L con mediana de 213 µg/L, y en Villa Ocampo 241,6±223,5 µg/L con mediana de 188 µg/L; mientras que en Rufino 544±349 µg/L con mediana de 442 µg/L y en Venado Tuerto 550±375 µg/L con mediana de 418 µg/L (media±DS). Los niveles de iodo en sal fueron similares en toda la provincia, promediando los 35,5 mg/kg. La prevalencia de muestras con concentraciones de iodo <15 mg/kg fueron del 0,3% para Reconquista, del 1,3% en Villa Ocampo, del 3 % en Rufino y del 4 % en Venado Tuerto. Concluimos que en la provincia de Santa Fe no existe endemia bociosa. Los autores declaran no poseer conflictos de interés.

A total of 1,470 primary school students were evaluated to monitor the prevalence of endemic goiter in four cit-ies of Santa Fe province: Reconquista (404) and Villa Ocampo (294) situated in the north, and Rufino (317) and Venado Tuerto (455) situated in the south of the province. Their age ranged from 6 to 14 years. Neck palpation was performed in all students; for the sake of consistency with monitoring performed in other provinces, palpation was performed by only one physician (HN). The goiter grading system was the same used in other surveys. After palpation, urine samples for iodine determination were randomly collected (109 from Reconquista, 105 from Villa Ocampo, 113 from Rufino and 139 from Venado Tuerto). Iodine was also measured in salt samples collected from the children's homes (337 from Reconquista, 227 from Villa Ocampo, 295 from Rufino and 422 from Venado Tuerto). Prevalence of goiter was 2.6 % without differences among cities. Urine iodine levels were significantly different between northern and southern cities: Reconquista had a mean of 238.6 ± 116 µg/L (median 213 µg/L) and Villa Ocampo had a mean of 241.6 ± 223.5 µg/L (median 188 µg/L), while in Rufino the mean was 544 ± 349 µg/L (median 442 µg/L) and in Venado Tuerto it was 550 ± 375 µg/L (median 418 µg/L; mean ± SD). Iodine contents in salt were similar across the province, with a mean of 35.5 mg/kg. Prevalence of salt samples with iodine concentration <15 mg/kg was 0.3 % in Reconquista, 1.3 % in Villa Ocampo, 3 % in Rufino, and 4 % in Venado Tuerto. We conclude that the province of Santa Fe, Argentina, is free from endemic goiter. No financial conflicts of interest exist.

Analysis of peripheral blood lymphocyte phenotype and function during dexamethazone treatment of progressive multiple sclerosis.

Five patients with chronic progressive multiple sclerosis (MS) and three control patients with lumbar disc herniation were treated with dexamethazone during 14 days. The effect on peripheral blood T-cell subsets and on the proliferative response of peripheral blood mononuclear cells (PBMC) to pokeweed mitogen (PWM) and anti-mu antibody was analyzed. Before treatment, the proportion of CD3+ and CD4+ PBMC was similar in MS and control patients, but the proportion of CD8+ and DR+ PBMC was lower and the PBMC were less responsive to anti-mu stimulation in MS patients compared to controls. Steroid treatment induced reversible granulocytosis and lymphocytosis. CD3+ and CD4+ cells increased and DR+ cells decreased in MS patients but not in controls. Proliferation of anti-mu stimulated PBMC increased in MS-patients during the two weeks of treatment, but decreased in controls. The enhancement in the MS patients of pre-existing immune abnormalities suggests that a cautious attitude is warranted in the use of steroid treatment in chronic progressive MS.

Paraplejia espástica e insuficiencia suprarrenal primaria: un caso de adrenomieloneuropatia / Spastic paraplegia and primary adrenal insuficiency: a case of adrenomyeloneuropathy

Un varón de 40 años se internó por dificultad creciente para la marcha que había comenzado 2 años antes y que lo había reducido a una silla o a la cama. Hacía 7 años se le había diagnosticado enfermedad de Addison y tomaba regularmente 20 mg/día de hidrocortisona oral. Su padre, un tío paterno y 2 hermanas están sanos; un hermano afectado por oligofrenia, disartria y dificultad para caminar falleció a los 9 años de edad. A su ingreso, el paciente estaba lúcido y orientado,; tenía hiperpigmentaciín leve de piel y mucosas, alopecía en cuero cabeludo y cola de cejas, testículos de 3,5 ml y paraplejía espástica; los miembros inferiores conservaban la sensibilidad táctil y dolorosa. La radiografía de tórax y la reacción de Mantoux eran normales. Las pruebas hormonales de laboratorio confirmaron la insuficiencia suprarrenal primaria (con conservación de la función de la zona glomerulosa) y un hipogonadismo primario; la función tiroidea era normal. La velocidad de conducción motora en miembros inferiores era baja (30-32 m/seg), con aumento de las latencias proximal y distal; esto y el EMG eran compatibles con polineuropatía de tipo mielinopático. Se comprobó leve atrofia cortical difusa (TAC) de cráneo); los potenciales evocados auditivos de tronco cerebral mostraron baja amplitud del complejo IV-V y tiempo de conducción central prolongado (5,3 mseg). Los ácidos grasos séricos eran cuantitativa y cualitativamente normales por cromatografía gaseosa. En la biopsia de nervio safeno se observó desmielinización segmentaria y degeneración axonal, sin infiltrados inflamatorios; el estudio ultraestructural demostró, en el citoplasma de algunas células de Schwann, inclusiones bilaminares, en su mayoría curvalíneas, que confirmaron el diagnósticos clínico de adrenomieloneuropatía. Esta rara enfermedad familiar de transmisión recesiva ligada al cromosoma X se origina en un trastorno del metabolismo de los ácidos grasos saturados de cadena muy larga, con compromiso funcional del sistema nervioso y de células productoras de hormonas esteroides