Oxygen toxicity in premature infants

Oxygen causes tissue injury through the formation of reactive oxygen intermediates and peroxidation of membrane lipids. Premature infants, who have severely reduced antioxidant defenses, are particularly sensitive to the toxic effects of oxygen. Supplemental oxygen in premature infants contributes to the development of chronic lung disease (bronchopulmonary dysplasia), characterized by dysregulated inflammation and altered expression of proteases and growth factors. This can result in fibrosis, asymmetric aeration, and respiratory insufficiency. Oxygen also induces aberrant physiologic responses that can be damaging in premature infants. For example, vasoconstriction in the retina is an early response to oxygen that can lead to vasoobliteration, neovascularization, and retinal traction (retinopathy of prematurity). Increasing knowledge of the mechanisms underlying oxygen toxicity in premature infants has suggested strategies to minimize tissue injury and to optimize long-term medical outcomes. These include limiting oxygen supplementation and light exposure, the use of antiinflammatory agents or antioxidants, and the use of room air in neonatal resuscitation.     

The ribotoxic stress response as a potential mechanism for MAP kinase activation in xenobiotic toxicity.

The article highlighted in this issue is "Vomitoxin-InducedCyclooxygenase-2 Gene Expression in Macrophages Mediated byActivation of ERK and p38 but Not JNK Mitogen-Activated ProteinKinases," by Yuseok Moon and James J. Pestka (pp. 373–382).     

Training of the oral and maxillofacial surgeon in implantology.

This article reports the results of a survey of oral and maxillofacial surgery residency programs regarding the teaching of implantology. The findings show that although oral and maxillofacial surgery residents receive as much or more didactic training than most trainees in other dental specialties, and much more extensive surgical experience, the teaching is not uniform and there is still need for improvement in some areas.     

First-line treatment for advanced non-small-cell lung cancer

With best supportive care alone, patients with metastatic non-small-cell lung cancer (NSCLC) have a median survival of 4 to 5 months and a 1-year survival rate of approximately 10%. Trials carried out in the 1980s and 1990s comparing chemotherapy to best supportive care reported variable efficacy results; however, a pivotal meta-analysis of these data indicated that cisplatin-based chemotherapy provided a survival benefit in advanced NSCLC. In the past decade newer agents such as gemcitabine (Gemzar), vinorelbine, paclitaxel, and docetaxel (Taxotere) have all demonstrated activity in NSCLC as single agents; consequently these agents have been combined with cisplatin or carboplatin. Randomized phase III trials comparing these "newer" platin-based doublets have failed to identify an optimal platinum-based doublet therapy regimen. Though it is clear that chemotherapy is an appropriate treatment for many patients with lung cancer, there a sense in which the use of traditional chemotherapeutic agents has reached a therapeutic plateau. Increased understanding of cancer biology has revealed numerous potential therapeutic strategies, including targeting the epidermal growth factor receptor, protein kinase C, rexinoid receptors, and the angiogenesis pathway. The Eastern Cooperative Oncology Group study E4599 comparing paclitaxel/carboplatin with/without bevacizumab is the first phase III randomized trial to show a survival advantage with the addition of a molecularly targeted agent to chemotherapy in the chemotherapy-naive patient population. Future studies will involve the evaluation of additional targeted agents plus chemotherapy as well as looking at combinations of these targeted agents alone or with chemotherapy.     

A systematic literature review of the clinical and epidemiological burden of acute lymphoblastic leukaemia (ALL)

Our goal was to identify and summarize the published literature pertaining to the incidence, prevalence, mortality, aetiology, clinical diagnosis, and management of acute lymphoblastic leukaemia (ALL). Acute lymphoblastic leukaemia represents 12% of all leukaemia cases, with a worldwide incidence projected to be 1-4.75 per 100,000 people. Italy, the United States (US), Switzerland, and Costa Rica are the countries with the highest incidence of ALL. Hereditary link, genetic defects, and possibly radiation or chemical exposures are listed amongst the most significant risk factors. Acute lymphoblastic leukaemia is predominantly a disease of childhood, but it affects adults as well. It accounts for 80% of all leukaemia cases in children. The incidence is slightly higher in men than in women and greater in white people than in black people. In 2003 in the US, there were an estimated 5800 deaths from ALL. Presenting signs and symptoms of ALL are fairly non-specific and include fever, anaemia, petechiae, and bone and joint pain. Staging of the disease and patient risk profile are routinely performed to define ALL subtypes and guide management. Chemotherapy, cranial radiation in patients with high-risk disease, and stem cell transplantation for selected patients are the prevalent therapies. Complete remission rates are high, especially amongst children (even 100%); however, long-term survival at 10 years (event-free survival) is in the range of 63% for children and 25-35% for adults. This implies that there is still a strong need for new therapies to maintain remission and prolong survival. Future treatment strategies may be driven by the patient's minimal residual disease status, a measure that more precisely defines remission, prognosis, responsiveness to therapy, and expected long-term survival.     

Adjuvant chemotherapy for non-small cell lung cancer: the new standard of care

Despite optimal surgical therapy for non-small cell lung cancer, approximately 50% of people ultimately die from recurrent disease. Clinical trials in the 1990s suggested a marginal survival advantage associated with adjuvant chemotherapy; however, as the benefit was relatively small and the chemotherapies were not well tolerated, adjuvant chemotherapy was not widely accepted. Over the past 3 years, several large randomized Phase III trials using modern platinum-based doublet regimens in selected patient populations have demonstrated significant survival advantages associated with adjuvant chemotherapy. The recent publication of the JBR10 study clearly exemplifies why this approach is now considered the standard of care for patients with operable non-small cell lung cancer.     

Benign epithelioid peripheral nerve sheath tumors of the soft tissues: clinicopathologic spectrum of 33 cases

Benign epithelioid peripheral nerve sheath tumors (BEPNSTs) have not been fully characterized, and their relationship to conventional schwannoma and neurofibroma has not been satisfactorily established. Herein, we detail the clinicopathologic features of 33 examples of BEPNST. The study included 22 females and 11 males ranging in age from 2 to 68 years (median, 31.5 years). Only one patient probably has neurofibromatosis type 1. The tumors were predominantly dermal/subcutaneous in location (85%) and involved the lower limb (n=15), upper limb (n=11), trunk (n=4), and head/neck (n=3). The lesions ranged in size from 0.3 to 6.8 cm (median, 1.1 cm). Microscopically, the tumors were generally well-circumscribed, uninodular, or multinodular masses. Twenty-six lesions were encapsulated. Tumors consisted of trabeculae, loosely arranged nodules, and cohesive nests of epithelioid tumor cells immersed in collagenous, myxohyaline, or chiefly myxoid stroma. A bland spindled cell component comprising 5% to 40% of the tumor was noted in 15 cases. Mitotic activity ranged from 0 to 6 mitoses/50 high power fields (mean, 1.5 mitoses/50 high power fields) with no abnormal division figures identified. Five lesions were considered atypical based on presence of focal nuclear/nucleolar enlargement and hyperchromasia. Immunohistochemical reactivity for Schwann cell-related markers in tumor cells included S-100 protein (20 of 20 cases), collagen type IV (10 of 10), laminin (8 of 8), nerve growth factor receptor, p75(7 of 8), CD57 (6 of 9), and glial fibrillary acidic protein (8 of 15). CD34-positive fibroblast-like cells were identified in all 12 neoplasms tested. Anti-epithelial membrane antigen highlighted perineurial cells in 9 of the 11 encapsulated tumors. Anti-neurofilament protein did not identify intralesional neuraxons in the 10 tumors evaluated. Eighteen tumors were subtyped as epithelioid neurofibromas. The remaining 15 cases showed some histologic features suggestive of schwannoma, but their uniform cellularity, absence of nuclear palisading, and presence of a significant CD34-positive spindled cell population in 5 cases led to their classification as "BEPNST of indeterminate histogenesis." Evaluation for loss of heterozygosity in 2 cases demonstrated deletion of genetic material on chromosome 22q and 17q involving NF2 and NF1 loci. However, sequencing of NF2 coding sequences revealed no mutations. Follow-up for 18 patients (median interval, 13.5 years), including 4 patients with tumors exhibiting cytologic atypia, revealed a nondestructive recurrence or persistent disease in 3 patients whose tumors lacked atypia, but no evidence of metastatic spread or tumor-related death. BEPNSTs are usually small neoplasms located in superficial soft tissue and have an excellent prognosis after complete local excision. Accurate subclassification of some of these lesions is difficult based on currently available techniques.