Israel Medical Association Journal

Paraneoplastic syndromes are disorders associated with cancer but without a direct effect of the tumor mass or its metastases on the nervous system. Small cell carcinoma of lung associated with paraneoplastic sensory neuronopathy and/or paraneoplastic encephalomyelitis with the presence of anti-Hu antibodies has been termed “anti-Hu syndrome. Anti-­Hu associated PSN-PEM is an immune disorder in which both cell-mediated and humoral mechanisms are involved. Patients are consiaered affected by Anti-Hu associated PSN-PEM when they develop clinical signs and symptoms of CNS dysfunction and/or sensory neuropathy not caused by metas­tases or other disorders, and serum or cerebrospinal fluid is positive for Hu abs. SCLC is found in more than 90% of patients with cancer and positive Hu abs. Individual patients with Hu abs associated to SCLC may suffer PSN-PEM, Iimbic encephalitis, brainstem encephalopathy, opsoclonus-myoclo­nus, paraneoplastic cerebellar degeneration or myelopathy. Hu abs have a specificity of 99% and sensitivity of 82% in detecting paraneoplastic neurological syndromes. There are two types of treatment: the first is to treat the cancer, the second is to suppress the immune reaction with the use of corticosteroids, cyclophosphamide, azathioprine, plasma ex­change, intravenous immunoglobulin and immunoadsorption however, treatment of paraneoplastic syndromes is generally unsatisfactory.

Background: Exposure of newborn animals to high concentrations of oxygen leads to diffuse alveolar damage similar to that seen in bronchopulmonary dysplasia in human infants. Therefore, neonatal rats are a suitable practical model of hyperoxic lung damage in human infants.

Objective: To determine the involvement of tumor necrosis factor-alpha and interleukin-6 in lung injury in neonatal rats exposed to 100% O2 concentration.

Methods: A randomized controlled study was designed in which litters of term Sprague-Dawley rat pups were assigned to experimental or control groups. The pups in the experimental group were placed in 100% O2 from birth for 9 days, while the control pups were placed in room air. Twelve to 15 pups from each group were sacrificed on day 1, 3, 6, 9 and 13 after birth for bronchoalveolar lavage collection and lung histologic study. The bronchoalveolar lavage fluid was assayed for TNFα and IL-6.

Results: Newborn rats exposed to 100% O2 for the first 9 days of life showed severe pulmonary edema and hypercellularity on days 1 and 3, which then improved to nearly complete resolution on days 6 and 9. Pulmonary TNFα was produced early on O2 exposure (day 3) and pulmonary IL-6 later (days 6 and 9).

Conclusions: Hyperoxia induces sequential production of pulmonary TNFα and IL-6, which corresponds to the severity of the pathological findings and the known inflammatory and anti-inflammatory role of these cytokines.

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TNFα= tumor necrosis factor-alpha

IL-6= interleukin-6