Both B and gammadelta TCR(+) lymphocytes regulate alphabeta TCR(+) lymphocytes involved in superantigen specific responses.

Endogenous superantigens (SAg) presented by MHC class II IA molecules induce slow-evolving negative selection of alpha beta T cells. The role of both B and gamma delta T cells on the regulation of these SAg-specific alpha beta T cell responses was addressed in IA(b+)IE(b-) C57BL/6 mice bearing genetically induced B cell and gamma delta T cell deficiencies. B lymphocytes were required in the negative selection of Vbeta5(+)/Vbeta12(+) CD4(+) T cells. In contrast, gamma delta T cells positively stimulated the utilization of the same SAg-responsive alpha beta T cell subsets. These differences started in mature CD4(+) thymocytes and extended to naive T cell pools for B cell negative selection, and up to memory T cells for gamma deltaT cell influences. The levels of SAg-responsive T cells did not vary between C57BL/6 and double deficient (B cell and gamma delta T cell-deficient) congenic mice, implying that both B and gamma delta T cells acted through independent mechanisms.

[Intestinal obstruction and sepsis caused by Torulopsis glabrata]. / Obstrucción intestinal y sepsis por Torulopsis glabrata.

A 27-year-old woman previously diagnosed of aplastic anemia secondary to treatment with gold salts for rheumatoid arthritis, presented with an episode of intestinal occlusion with acute renal failure. A CT scan revealed dilated intestinal loops, thickening of the ileum wall without cecal involvement, and multiple punctuate lesions (micro-abcesses) of liver, spleen and kidneys. At laparotomy, one meter of proximal jejunum was resected. The cultures of jejunal biopsy specimens yielded Torulopsis glabrata. The patient underwent multiorgan failure and died on the 8th postoperative day.

[Morphopathological changes before and after biliodigestive derivation in experimental cirrhosis induced by biliary ligation in the rat]. / Cambios morfopatológicos pre y postderivación biliodigestiva en cirrosis experimental por ligadura de vía biliar en rata.

OBJECTIVE: Study of the hepatic morphological and biochemical changes in an experimental model of cirrhosis in rat by ligation of the common bile duct before and after bilioduodenal anastomosis. DESIGN: Ligation of the common bile duct in a group of 80 female Wistar rats during 30 days. Liver biopsy for histological studies and staining, blood samples for biochemical determination were taken, and a bilioduodenal anastomosis was constructed. 30 days later new liver specimens and blood samples were taken. A control group consisted of 10 rats. RESULTS: 30 days after biliary obstruction histological changes were characterized by occurrence of bile canalicular proliferation and portal fibrosis that rounded hepatic lobules. No well-defined nodules indicative of cirrhosis were seen. There was cholestasis with an increase in serum bilirubin, alkaline phosphatase and transaminase levels, and a decrease of albumin levels. Survival was 63.7%. Thirty days after biliary diversion (60 days after ligation) the normal lobular pattern was disorganized and regenerative nodules indicative of cirrhosis appeared, separated by narrow fibrous connective tissue septa, in 65% of rats. Bilirubin levels returned to normal values. Alkaline Phosphatase and transaminase levels remained high and albumin levels remained low. Overall survival was 25%. CONCLUSIONS: 30 days after biliary obstruction there are no regeneration nodules indicative of cirrhosis. There is a precirrhotic change, biliary fibrosis. Biliary diversion does not improve the histological changes and regeneration nodules and cirrhosis appear in 65% of animals.

Interleukin 2 abrogates the nonresponsive state of T cells expressing a forbidden T cell receptor repertoire and induces autoimmune disease in neonatally thymectomized mice.

Under physiological conditions, the vast majority of T cells differentiate in the thymus, an organ that provides an optimal microenvironment for T cell maturation and shapes the T cell repertoire via positive and negative selection processes. In the present report, we demonstrate that neonatal thymectomy of CBA/H mice results in a diminution of T cells in peripheral lymphoid organs (spleen, lymph nodes), but is followed by a marked transient (12 wk) increase in Thy-1+ CD3+ cells in the peritoneal cavity. These cells exhibit predominantly a double-negative (CD4-CD8-) phenotype among which products of the T cell receptor (TCR) V beta 11 gene family (i.e., an I-E-reactive TCR normally deleted in I-E-bearing CBA/H mice) are selectively overexpressed. This observation suggests that, under athymic conditions, T cell differentiation and/or accumulation may occur in the peritoneal cavity. Intraperitoneal inoculation of an interleukin 2 (IL-2) vaccinia virus construct that releases high titers of human IL-2 in vivo induces conversion of these double-negative T cells to either CD4+ CD8- or CD4- CD8+ single positives, and allows in vitro stimulation of TCR V beta 11-bearing cells with a clonotypic anti-V beta antibody. Since IL-2 induces autoimmune manifestations (DNA autoantibodies, rheumatoid factors, and interstitial nephritis) in thymectomized CBA/H mice, but not in sham-treated littermates, this lymphokine is likely to enhance the autoaggressive function of T cells that bear forbidden, potentially autoreactive TCR gene products and that are normally deleted in the thymus.

[Splenic hydatid cyst. A report of 16 cases]. / Quiste hidatídico de bazo. Aportación de dieciséis casos.

The authors' experience with splenic hydatidosis is presented. Sixteen cases, representing 3% of the hydatidosis treated surgically in our center, are reviewed. Pain in the left upper quadrant, splenomegaly and calcifications detected by simple abdominal radiology are the most suggestive indications. The definitive diagnosis is based on abdominal echography and CT scan, which have the greatest sensitivity and specificity. The treatment should be surgical, attempting to preserve as much splenic tissue as possible, although in our experience, it is infrequent that conservative treatment can be used due to massive involvement of the spleen.