Heterotopic heart transplants in Biomphalaria glabrata (mollusca: pulmonata). Fate of congeneric xenografts

Hearts were implanted heterotopically into the hemocoel of NIH albino Biomphalaria glabrata from three xenogeneic donor snails, including two New World (B. obstructa, B. tenagophila) and one Old World (B. alexandrina) species, as well as from wild type allogeneic donors. Recipients were examined histologically at 1, 3, 7, 10, 15, 30, 60, 120, and 180 days postimplantation (PI). Grafts from all four donor species were temporarily infiltrated by recipient hemocytes at early intervals PI and in most instances also became encapsulated. Furthermore, the grafts subsequently showed histopathological alterations and abnormal heartbeat relative to preimplantation controls. However, hemocytic reactions eventually subsided, the implants remained structurally intact, and implant myocardial cells both maintained high levels of intracellular glycogen and continued to contract rhythmically for 6 months. No major differences occurred in fates among different xenografts, or between xenografts and allografts. Our observations of prolonged xenograft survival differ from those of previous investigators, most of whom have reported rapid destruction of implanted xenogeneic tissues in molluscs.     

Influences of chorion type on measurements of the corpus callosum in adult monozygotic male twins?

MRI imaging was used to estimate volumes of corpus callosum structure in 45 pairs of identical (monozygotic, MZ) twins from the National Heart, Lung, and Blood Institute (NHLBI) twin study. Age range of the study subjects was from 68–78 years. Finger, palm, and footprint data (dermatoglyphics) collected at previous examinations of the NHLBI twin study were available for 39 pairs. The dermatoglyphics were scored for an index to retrospectively assess chorion type in MZ twin‐pairs. The results indicated an association between variability in various structures of the corpus callosum with some of these dermatoglyphic traits, suggesting greater structural variation within pairs with dichorionic placentas. In contrast, total intracranial volume, which has similar heritability estimates as a result of shared genetic effects with the corpus callosum, was unrelated to the dermatoglyphic traits. The results provide indirect evidence that the intrauterine environment may influence twin‐pair similarity of corpus callosum measures in adults. Am. J. Hum. Biol. 14:338–346, 2002. © 2002 Wiley‐Liss, Inc.     

The use of monoclonal antibodies against primary myeloid granules in normal and leukemic cells.

Three monoclonal antibodies, K101, D46, and H36/71 (CD15), reactive with membrane components of primary granules of human promyelocytes, were studied to assess their binding to normal and leukemic cells. Using the alkaline phosphatase antialkaline phosphatase technique, these antibodies were applied to sections of normal organs and to peripheral blood and bone marrow films from hematologically normal individuals and patients with hematologic malignancies. In control experiments, antibodies showed reactivity with cytoplasmic constituents of granulocytes from the promyelocytic to the neutrophilic stage. In acute myeloid leukemia, antibody K101 was positive (more than 20% of blasts) in 13 of 21 (62%) cases, while antibody D46 was positive in 11 of 17 (65%) cases. Antibody H36/71 was positive in only 4 of 24 (17%) cases of acute myeloid leukemia. At least one marker was present in 6 of 8 (75%) cases of acute lymphoblastic leukemia with myeloid antigen-positive blasts and was negative in 20 cases of acute lymphoblastic leukemia with myeloid antigen-negative blasts. These results support the view that abnormal granules (with defective expression of the D46, K101, and H36/71 antigens) form in blastic and leukemic cells of patients with acute myeloid leukemia. Data also suggest that membrane components of myeloid granules are made in the cytoplasm of cells from some acute lymphoblastic leukemia patients with myeloid antigen-positive blasts.     

Antigen-specific desensitization of patients allergic to penicillin

Three penicillin-allergic patients with life-endangering infections requiring β-lactam antibiotic therapy were desensitized by means of increasing oral then parenteral doses and were treated with full doses of β-lactam agents. Malignant otitis externa caused by Pseudomonas aeruginosa, osteomyelitis caused by Staphylococcus aureus, and bacterial endocarditis caused by an enterococcus were treated with carbenicillin, nafcillin, and benzylpenicillin G, respectively. No acute allergic reactions occurred during desensitization or within 1 wk of the onset of therapy. Immediate wheal and flare skin-test reactions to β-lactam determinants diminished or became negative after the desensitization procedure in each patient. Wheal and flare responses provoked by histamine, compound 48/80, and environmental antigens were not affected by the desensitization procedure or continued β-lactam drug therapy. Mild urticaria appeared after 15 days of penicillin therapy in one patient and after 23 days of carbenicillin therapy in another patient. Skin-test reactions to penicillin reagents had reverted to positive at the time of the urticarial reactions. One patient developed a severe immune hemolytic anemia after 10 days of therapy with nafcillin. The results of this study indicate that acute clinical desensitization of these three penicillin-allergic patients was associated with antigen-specific desensitization of tissue mast cells.     

Superantigen responses and co-stimulation: CD28 and CTLA-4 have opposing effects on T cell expansion in vitro and in vivo

Co-stimulation via the CD28/CTLA-4 system appears critical forT cell proliferation to peptide antigens presented in associationwith MHC. In this study, we examine the roles of CD28 and CTLA-4in the response of murine T cells to the superantigen staphylococcalenterotoxin B (SEB). In vitro, antibodies against B7-1/B7-2or Fab fragments of anti-CD28 antibodies significantly inhibitthe response of splenocytes to SEB. Conversely, Fab fragmentsof anti-CTLA-4 antibodies augment the proliferative response.Further, addition of blocking antibodies directed against B7-1/B7-2augment proliferation co-stimulated by intact anti-CD28 antibodies.These data support the hypothesis that CD28 and CTLA-4 exertopposing effects upon early T cell activation. In vivo, Intactanti-CD28 antibodies and non-stimulatory Fab fragments of anti-CD28appear to have similar inhibitory effects upon the expansionof V_ß8⁺ T cells. In contrast, both intact and Fabfragments of anti-CTLA-4 appear to amplify this expansion. Weconclude that the SEB response is significantly augmented byCD28-derived signaling and this in turn may be attenuated bysignals through CTLA-4.     

Problem behavior in boys with fragile X syndrome

This study examines problem behavior over time in 59 boys with fragile X syndrome (FXS), aged 4-12 years, using the Child Behavior Checklist (CBCL). Approximately 49% of the boys scored within the borderline or clinical range on total problem behavior, while 56-57% scored in the borderline or clinical range on the attention and thought problems subscales, and 26% scored in this range on the social problems subscale. With a mean of 2.5 assessments per child, behavior problems were stable during the 3-year period of study. Total problem behavior was higher for children who displayed autistic behavior, were rated as low in adaptability, had mothers with higher maternal education levels, and were on medication. Mothers with more education also rated their children as having more attention, thought, and total problems. Children taking medication differed from boys who were not taking medication on social problems, but not on attention and thought problems. Low adaptability and more autistic characteristics predicted thought problems.     

Teaching medical students about medical errors and patient safety: evaluation of a required curriculum.

PURPOSE: To assess the effectiveness of a brief curriculum about patient safety and medical errors with third-year medical students. METHOD: From 2000-03, third-year medical students at New York Medical College, Valhalla, New York, were required to participate in a new curriculum on patient safety and medical errors during their family medicine clerkships. Five hundred seventy-two students participated in a four-hour curriculum that included interactive discussion, readings, a videotape session with a standardized patient, and a small-group debriefing facilitated by a family physician. Before and after participating in the curriculum, students were asked to complete questionnaires on self-awareness about patient communication and safety. Curriculum evaluations and follow-up surveys were also distributed. Responses to each statement on the before and after questionnaires were compared using the Wilcoxon signed-rank test for matched data. RESULTS: Five hundred eleven (89%) students reported that the opportunity to present an error to a patient increased their confidence about discussing this issue with patients, and 537 (94%) students reported that they strongly agreed or agreed that the standardized patient and feedback exercise was a useful learning experience. A total of 535 before and after questionnaires were used in the analysis. A comparison of before and after questionnaire data revealed statistically significant increases in the self-reported awareness of students' strengths and weaknesses in communicating medical errors to patients (p 相似文献   

Molecular cloning and characterization of the 78-kilodalton glucose-regulated protein of Trypanosoma cruzi.

The protozoan Trypanosoma cruzi is the etiologic agent of Chagas' disease, an illness responsible for morbidity and death among millions of Latin Americans. Mice also develop this disease when infected with T. cruzi and are a useful model organism for the study of parasite-specific immune responses. To identify immunogenic T. cruzi antigens, serum from an infected mouse was used to isolate clones from a T. cruzi epimastigote cDNA expression library. One of these clones was found to encode the 78-kDa glucose-regulated protein (grp78), the endoplasmic reticular member of the 70-kDa heat shock protein (hsp70) family. Like the mammalian and yeast grp78s, the T. cruzi protein contains an endoplasmic reticular leader peptide and a carboxyl-terminal endoplasmic reticular retention sequence. T. cruzi grp78 is encoded by a tandemly arranged family of three genes located on a chromosome of 1.6 Mb. The effects on grp78 expression of heat shock and tunicamycin treatment, the latter of which specifically stimulates mammalian grp78, were investigated. While the level of the grp78 protein remained constant under all circumstances, grp78 mRNA was unaffected by heat shock but induced fivefold by tunicamycin. Finally, we found that grp78 is the most immunogenic of the T. cruzi heat shock proteins we have characterized, reacting strongly in immunoblots with sera from infected mice.