Continuous extrapleural intercostal nerve block for post thoracotomy analgesia in children

The influence of the nicotine antagonist dihydro-beta-erythroidine (DH beta E) was examined on various behavioural effects of nicotine in rats. Motor activity was recorded in photocell cages whereas discriminative stimulus effects were examined using two-lever drug discrimination procedures with a tandem schedule of food reinforcement (n = 8 throughout). DH beta E (0.1-3.2 mg/kg) failed to antagonise the decreases in motor activity that nicotine (0.4-0.6 mg/kg) produced in experimentally naive rats, whereas mecamylamine (1.5 mg/kg) completely blocked this effect of nicotine. DH beta E (0.1-3.2 mg/kg) antagonised the increases in motor activity that nicotine (0.4 mg/kg) produced in rats with extensive previous exposure to both nicotine and the photocell apparatus. In rats trained to discriminate either 0.1 or 0.4 mg/kg nicotine from saline, DH beta E (0.1-3.2 mg/kg) blocked the discriminative stimulus effect of nicotine. The block of the discriminative effect could be reversed by increasing the dose of nicotine; DH beta E (1.6 mg/kg) shifted the dose-response curve for nicotine discrimination to the right by a factor of 9.4. In addition, nicotine in doses of 0.32-0.64 mg/kg decreased the overall rate of lever pressing but DH beta E (1.6 mg/kg) did not influence the dose-response curve for this effect. Thus, DH beta E potently blocked the locomotor activating and discriminative stimulus effects of nicotine at doses that did not antagonise its locomotor depressant and operant response rate-reducing effects. This selective blockade supports the involvement of different subtypes of nicotinic receptor in the mediation of diverse behavioural effects. Furthermore, the rightward shift of the dose-response curve for nicotine discrimination suggested a competitive mode of action for DH beta E.     

The murine Tcl1 oncogene: embryonic and lymphoid cell expression

In human leukemias and lymphomas nonrandom chromosomal rearrangements cause changes in cell growth and/or survival in such a way as to promote malignancy. The detailed study of the biochemical and genetic pathways altered in human cancer requires the identification or development of models to allow the study and manipulation of cancer gene function. Recently, the breakpoint gene TCL1, involved in chromosome translocations observed mostly in mature T-cell proliferations and chronic lymphocytic leukemias (CLL), was isolated and characterized, and showed to be part of a new gene family of proteins involved in these tumors. The murine Tcl1 gene, is similar in sequence to the murine and human MTCP1 gene also involved in T cell leukemias. The murine Tcl1 gene was shown to reside on mouse chromosome 12 in a region syntenic to human chromosome 14. Furthermore, we show that the murine Tcl1 gene is expressed early in mouse embryonic development and demonstrates expression in fetal hematopoietic organs as well as in immature T and B cells. Characterization of the murine Tcl1 gene will help in developing a mouse model of CLL and would provide the best opportunity to study and decipher the role of TCL1 in malignant transformation.     

Spray forming technology for military applications

Over the past five years, the Annapolis Detachment, Carderock Division, Naval Surface Warfare Center (formerly David Taylor Research Center) has established a state- of- the- art spray forming facility for the study and exploitation of this near net shape manufacturing process. Spray forming is a single step gas atomization/deposition process which yields ferrous and nonferrous, near final shape, near fully dense preforms that has proven to be a viable and cost effective alternative to conventional metalworking technology for the production of material preforms with properties surpassing those of their cast and wrought counterparts. Current programs at Carderock Divison Naval Surface Warfare Center are aimed at optimization of the process, certification of the spray formed products and industrialization of the technology.     

Ovarian neoplasms in children

OBJECTIVE: To review the clinical presentation, treatment, and outcome in a series of children with ovarian neoplasms. DESIGN: A retrospective review of the medical records in a case series of 29 girls with ovarian neoplasms. The length of follow-up ranged from 6 months to 7 1/2 years and averaged 3.0 years in the girls with malignant tumors. SETTING: The patients were treated at a large referral children's hospital. PATIENTS: Twenty-nine girls with ovarian neoplasms were treated from 1976 to 1992. The average age of the patients was 10 years and ranged from 2 to 16 years. MAIN OUTCOME MEASURES: The principal outcomes examined were mortality and surgical morbidity. RESULTS: The most common presenting symptoms for these ovarian tumors in pediatric patients included chronic abdominal pain, an abdominal mass, or distention. Three girls presented with precocious puberty or hirsutism. In 27 cases, the tumor was a primary ovarian lesion. In two patients, the ovarian mass was the presenting finding for a stage IV non-Hodgkin's lymphoma. Seventeen tumors were benign and 12 were malignant. Tumors originating from the germ-cell line predominated (n = 17). Seven of the 10 ovarian malignant neoplasms were stage I at the time of diagnosis. All but one of the girls with malignant tumors received either adjunctive radiation therapy or multiple-agent chemotherapy. Two girls with sex cord/stromal cell tumors who presented with stage I disease ultimately developed widespread metastases. Both girls with large epithelial tumors survived. All of the girls with benign tumors and seven (70%) of 10 with malignant lesions survived. CONCLUSION: Ovarian tumors are unusual lesions in the pediatric population. Unlike in adults, such neoplasms generally originate from the germ-cell line. Whereas most ovarian tumors in girls are benign, some children have malignant tumors that are very aggressive and do not respond well to adjuvant therapy. In particular, malignant sex cord/stromal cell tumors, even when they present at an early stage, may behave unpredictably.