Perforated colorectal neoplasms: correlation of clinical, contrast enema, and CT examinations

Results of clinical, contrast enema (CE), and computed tomographic (CT) examinations in 39 patients with perforated colorectal neoplasms were retrospectively reviewed. Twenty patients were toxemic at initial presentation, but in only four patients was the diagnosis of perforated colorectal neoplasm initially suspected clinically. CE study was performed in 22 patients and enabled the diagnosis of perforated neoplasm in 11 cases, neoplasm alone in eight, and neither neoplasm nor perforation in three. CT was performed in 38 patients and enabled the diagnosis of perforated neoplasm in 36; pericolic phlegmon but no mass lesion was evident in two. In 16 patients, CT also demonstrated metastatic disease. Because of its reliability in establishing the diagnosis and staging the extent of the inflammatory and neoplastic disease, CT is indicated in cases of suspected or proved perforated colorectal neoplasm and in cases in which CE study findings are indeterminate or suggestive of perforated neoplasm.     

Frequent ongoing T-cell receptor rearrangements in childhood B- precursor acute lymphoblastic leukemia: implications for monitoring minimal residual disease

Crosslineage T-cell receptor delta (TCR delta) rearrangements are widely used as tumor markers for the follow up of minimal residual disease in childhood B-precursor acute lymphoblastic leukemia (ALL) by polymerase chain reaction (PCR). The major drawback of this approach is the risk of false-negative results due to clonal evolution. We investigated the stability of V delta 2D delta 3 rearrangements in a group of 56 childhood B-precursor ALL patients by PCR and Southern blot analysis. At the PCR level, V delta 2D delta 3-to-J alpha rearranged subclones (one pathway for secondary TCR delta recombination) were demonstrated in 85.2% of V delta 2D delta 3-positive patients tested, which showed that small subclones are present in the large majority of patients despite apparently monoclonal TCR delta Southern blot patterns. Sequence analysis of V delta 2D delta 3J alpha rearrangements showed a biased J alpha gene usage, with HAPO5 and J alpha F in 26 of 32 and 6 of 32 clones, respectively. Comparison of V delta 2D delta 3 rearrangement status between diagnosis and first relapse showed differences in seven of eight patients studied. In contrast, from first relapse onward, no clonal changes were observed in six patients studied. To investigate the occurrence of crosslineage TCR delta rearrangements in normal B and T cells, fluorescence-activated cell sorter-sorted peripheral blood CD19+/CD3- and CD19-/CD3+ cell populations from three healthy donors were analyzed. V delta 2D delta 3 rearrangements were detected at low frequencies in both B and T cells, which suggests that V delta 2-to-D delta 3 joining also occurs during normal B-cell differentiation. A model for crosslineage TCR delta rearrangements in B-precursor ALL is deduced that explains the observed clonal changes between diagnosis and relapse and is compatible with multistep leukemogenesis of B-precursor ALL.     

Interaction between hamartin and tuberin, the TSC1 and TSC2 gene products

Tuberous sclerosis (TSC) is an autosomal dominant disorder caused by a mutation in either the TSC1 or TSC2 tumour suppressor gene. The disease is characterized by a broad phenotypic spectrum that can include seizures, mental retardation, renal dysfunction and dermatological abnormalities. TSC2 encodes tuberin, a putative GTPase activating protein for rap1 and rab5. The TSC1 gene was recently identified and codes for hamartin, a novel protein with no significant homology to tuberin or any other known vertebrate protein. Here, we show that hamartin and tuberin associate physically in vivo and that the interaction is mediated by predicted coiled-coil domains. Our data suggest that hamartin and tuberin function in the same complex rather than in separate pathways.      

Leukotriene B4 Receptor (BLT-1) Modulates Neutrophil Influx into the Peritoneum but Not the Lung and Liver during Surgically Induced Bacterial Peritonitis in Mice

Leukotriene B₄ (LTB₄) is a rapidly synthesized, early neutrophil chemoattractant that signals via its cell surface receptor, BLT-1, to attract and activate neutrophils during peritonitis. BLT-1-deficient (BLT-1^−/−) mice were used to determine the effects of LTB₄ on neutrophil migration and activation, bacterial levels, and survival after cecal ligation and puncture (CLP). Male BLT-1^−/− or wild-type (WT) BALB/c mice underwent CLP. Tissues were harvested for determination of levels of bacteria, myeloperoxidase (MPO), LTB₄, macrophage inflammatory protein 2 (MIP-2), and neutrophil (polymorphonuclear leukocyte [PMN]) numbers at 4 and 18 h after CLP. PMN activation was determined by an assessment of phagocytosis ability and CD11b expression. Survival was also determined. BLT-1^−/− mice had decreased numbers of PMNs in the peritoneum at both 4 and 18 h after CLP but increased numbers of PMNs in the blood at 18 h compared with WT mice. Liver and lung MPO levels were significantly higher in BLT-1^−/− mice at both 4 and 18 h after CLP, with increased bacterial levels in the blood, the liver, and peritoneal fluid at 4 h. Bacterial levels remained higher in peritoneal fluid at 18 h, but blood and liver bacterial levels at 18 h were not different from levels at 4 h. PMN phagocytosis and CD11b levels were decreased in BLT-1^−/− mice. LTB₄ levels were similar between the groups before and after CLP, but MIP-2 levels were decreased both locally and systemically in BLT-1^−/− mice. Survival was significantly improved in BLT-1^−/− mice (71%) compared with WT mice (14%) at 48 h post-CLP. Thus, LTB₄ modulates neutrophil migration into the mouse peritoneum, but not the lung or liver, after CLP. Despite higher bacterial and PMN levels at remote sites, there was increased survival in BLT-1^−/− mice compared to WT mice. Decreased PMN activation may result in less remote organ dysfunction and improved survival.     

Mutation analysis of 184 cystic fibrosis families in Wales.

We describe a molecular analysis of 184 cystic fibrosis (CF) families in Wales. To determine accurate frequency data for the CF mutations in the Welsh population, families with at least three Welsh grandparents were strictly regarded as Welsh. Of these 74 families, we have identified approximately 90% of mutations causing CF, with delta F508 accounting for 71.8% and 621 + 1G greater than T 6.7%. We observed a significant difference between the Welsh and Scottish frequencies of 621 + 1G greater than T. To allow the rapid and efficient screening for the more common mutations we modified a multiplex used by Watson et al enabling the detection of delta F508, G551D, and R553X simultaneously with 621 + 1G greater than T. In parallel to this system we ran the Cellmark Diagnostics ARMS multiplex kit, which detects delta F508, 621 + 1G greater than T, G551D, and G542X. RFLP analysis of the 184 families shows that the delta F508 chromosomes are almost exclusively found on the B haplotype (XV2c 1, KM19 2); the other CF mutations have more heterogeneous backgrounds. Strong haplotype correlations exist between the markers XV2c, KM19, D9, and G2 and the other CF mutations. Haplotype data suggest that there are at least seven mutations that remain to be identified in these families.