CGA-7 and HHF, two monoclonal antibodies that recognize muscle actin and react with adherent cells in human long-term bone marrow cultures

The CGA-7, a monoclonal antibody that reacts with smooth muscle cell actin but not with endothelial cell or fibroblast actin, and HHF, a monoclonal antibody that reacts with smooth muscle, skeletal muscle, and cardiac muscle actin, both recognize microfilaments present within adherent cells from actively hematopoietic human long-term marrow cultures. Macrophages, monocytes, and cultured marrow fibroblasts do not react with either antibody. These data suggest that the anti-actin antibodies may serve as useful markers for in vitro microenvironmental cells and lend support to the hypothesis that stromal cells from long- term marrow cultures are different from marrow fibroblasts and may constitute a unique cell lineage.     

Horseshoe tract of anal fistula: bad luck or an avoidable extension? Lessons from 82 cases

Aim The aim of this study was to analyse the characteristics of horseshoe tract formation in anal fistula. Method We retrospectively analysed the data from all consecutive patients who underwent surgery for an anal fistula from November 2004 to March 2011. A horseshoe tract was defined as a circumferential extension connecting both sides of the anorectum. Results During the period of analysis, 1876 patients were operated on for a fistula. Of these, 82 (4.4%) had a horseshoe extension. The majority (72%) were male and the median age was 46 (17–84) years. The primary tract was high transsphincteric in 90% of cases and the primary opening was posterior in 65% of cases. The location of the horseshoe extension was posterior in 66% of cases with spread in the deep perianal space in 62%. In all, 71% were cryptoglandular and 24% were seen in Crohn’s disease (20). Of the 62 non‐Crohn’s patients previous treatment was common and included surgery (42), antibiotics alone (41) and non‐steroidal anti‐inflammatory drugs (21). Conclusion Horseshoe extension in anal fistula is uncommon. With Crohn’s disease excepted, the majority had had previous treatment.     

Inducible expression of dominant negative insulin-like growth factor I receptor in MCF-7 breast cancer cells

The insulin-like growth factor I receptor (IGF-IR) is expressed in many cell types and is critical for normal growth and development. In the healthy mammary gland, the role of IGF-IR is not fully elucidated. However, IGF-IR, which is primarily expressed in the mammary epithelial cells, is known to play an obligatory role in cellular transformation, facilitating the progression to breast cancer. We have utilized the tetracycline regulatory (tet-on) system to generate an in vitro model system to allow us to further investigate IGF-I/IGF-IR function in mammary epithelial cells. A plasmid construct containing a mutant IGF-I receptor (IGF-IR-DN) fused to the tetracycline operator (tetOPh_CMV-IGF-IR-DN) was stably transfected into MCF-7 human breast cancer cells. The conditional regulation of the IGF-IR-DN gene expression was studied in four independent clonal lines. The translated IGF-IR-DN protein was detected only in the stably transfected doxycycline-induced cells, and its expression was up-regulated (three- to sixfold) following induction. IGF-I stimulated cell proliferation diminished (twofold) in doxycycline-induced cells compared to uninduced cells, demonstrating that the transgene construct was functional and ruling out any pleiotropic effect that may be attributed to doxycycline. Interestingly, autophosphorylation of the IGF-IR and phosphorylation of the downstream substrate, insulin receptor substrate-1 (IRS-1), was not inhibited in doxycycline/IGF-I treated cells, suggesting the possibility that activation of downstream substrates other than the IRS-1 may be critical for optimal cell proliferation. This novel in vitro model should allow us to more directly examine the role of IGF-I/IGF-IR signaling and function in mammary epithelial cells.     

Comparison of the native prothrombin antigen and the prothrombin time for monitoring oral anticoagulant therapy

We have measured the fully carboxylated (native) prothrombin antigen and the undercarboxylated (abnormal) prothrombin antigen in patients treated with sodium warfarin using specific immunoassays to evaluate a new approach for monitoring oral anticoagulant therapy. Plasma and serum samples (391) were assayed for the prothrombin time, native prothrombin antigen, and abnormal prothrombin antigen. The results were correlated with the presence of bleeding or thromboembolic complications at the time of phlebotomy. The native prothrombin antigen correlated with the occurrence of complications in 95% of samples. Of 13 samples from patients with bleeding complications, 13/13 (100%) had a native prothrombin of 12 micrograms/mL or lower. Of seven samples from patients with thromboembolic complications, 6/7 (86%) had a native prothrombin of 24 micrograms/mL or greater. By comparison, a prothrombin time index of 1.5 to 2.5, 1.5 to 2.2, 1.5 to 2.0, or 1.3 to 1.8 identified 6/20 (30%), 9/20 (45%), 11/20 (55%), or 12/20 (60%) patients at risk, respectively. Although the prothrombin time index did correlate with the presence of bleeding complications, the native prothrombin antigen correlated closely with the presence of bleeding and thromboembolic complications. According to these results, the native prothrombin antigen, maintained in a range of 12 to 24 micrograms/mL by regular adjustment of the warfarin dosage, may be associated with a reduced risk of complications due to excessive or insufficient warfarin therapy. On the basis of these preliminary data, we recommend that the native prothrombin antigen be considered to monitor warfarin therapy.     

Generational differences in the age at diagnosis with Ibd: genetic anticipation, bias, or temporal effects

OBJECTIVE: Previous cross-sectional research has demonstrated generational differences in age at diagnosis (AAD) in inflammatory bowel disease (IBD). This observation has at times been ascribed to genetic anticipation, but could also be due to biases related to case ascertainment or follow-up or to temporal changes in IBD epidemiology. We aimed to explore this issue using a population-based database. METHODS: In 1995 we used the comprehensive administrative databases in the province of Manitoba, Canada to establish a population-based IBD Research Registry that includes clinical and demographic information for persons. We contacted those subjects within our Research Registry who reported having any family members with IBD and their family members for verification of diagnosis and AAD. Differences in AAD between familial pairs were calculated. In addition, to assess whether duration of follow-up accounted for generational differences in AAD, we computed the mean AAD for subjects with and without family histories of IBD based on age at the time of interview (i.e., < 45 and > or = 45 yr of age). RESULTS: Of the 2445 persons with IBD in the Research Registry, 548 reported positive family histories, and 315 of these (58%) were reached by telephone. There were 169 Crohn's disease and 146 ulcerative colitis subjects with positive family histories. The mean AADs for the parents, aunts/uncles, and grandparents were significantly greater than the mean AADs for the children, nieces/nephews, and grandchildren, respectively. There was a doubling of the mean AAD when comparing the grandparent/grandchild cases with the parent/child or aunt/uncle-niece/nephew cases. No statistically significant difference in anticipation was observed, whether or not the older generation was male or female or had Crohn's disease or ulcerative colitis. The AAD was substantially greater for those interviewed at > or = 45 yr of age for subjects with and without family histories. However, there was no substantial difference in mean AAD between familial and nonfamilial subjects. CONCLUSION: The present study has demonstrated that there is a tendency for children to be younger than their parents at the time of diagnosis of familial IBD, and that this difference in mean AAD is almost doubled for grandparent/grandchild pairs. However, we conclude that these differences are most likely due to a bias based on length of follow-up or recent multigenerational temporal changes in the risk of IBD, or both.     

Synthesis and secretion of a high molecular weight form of nerve growth factor by skeletal muscle cells in culture.

Rat skeletal muscle cells and a cloned myogenic cell line synthesize and secrete in culture a molecule that is immunologically and biologically indistinguishable from the active form of nerve growth factor (NGF) from mouse submandibular gland. This protein can be detected in medium conditioned by muscle cells both before and after fusion and in the soluble fraction of muscle cell homogenates. Chromatographic data also reveal that the molecular properties of muscle cell NGF differ from those of the growth factor purified from mouse submandibular glands. Muscle cell NGF has a molecular weight between 140,000 and 160,000, whereas purified mouse gland NGF has a molecular weight of 26,000. The biologic function of muscle cell NGF is not known, although it could be that it plays some role relating to the association of nerves and muscle in vivo.