Carcinomatous meningitis arising from primary nasopharyngeal carcinoma.

Carcinomatous meningitis, also known as leptomeningeal metastasis and meningeal carcinomatosis, is the invasion of neoplastic cells into the leptomeninges. Head and neck cancers, especially nasopharyngeal carcinoma, give rise to carcinomatous meningitis very infrequently. In this case report, we present a rare case of carcinomatous meningitis with nasopharyngeal carcinoma as the primary source. In 1987, a 45-year-old white female presented with a few year history of chronic bilateral serous otitis media. She also complained of intermittent diplopia, right facial pain, right-sided headache, and, finally, right facial palsy. The patient was subsequently diagnosed with nasopharyngeal carcinoma by biopsy and treated with radiation as well as chemotherapy. Her neurological symptoms improved, and she did fairly well for several years. However, various neurologic symptoms started to recur, including right facial weakness, right facial numbness in the distribution of all 3 divisions of cranial nerve (CN) V, loss of taste as well as smell, and diplopia. In 1993, magnetic resonance imaging scan of the head revealed recurrence of nasopharyngeal carcinoma with involvement of the ethmoid sinuses as well as extension of the tumor into the frontotemporal leptomeninges. Over the course of the next 3 years, the patient experienced a very gradual decline with involvement of almost all of the CNs (CN I, II, III, V, VI, VII, VIII, IX, X, XII). This case report of carcinomatous meningitis from primary nasopharyngeal carcinoma is one of the few reported in the literature. Although very rare, nasopharyngeal carcinoma can give rise to carcinomatous meningitis, probably by direct invasion of malignant cells. We also review the literature with respect to the diagnosis and treatment of carcinomatosis meningitis.

Retrospective assessment of risk factors to predict tunneled hemodialysis catheter outcome.

PURPOSE: To identify factors that may influence the function, outcome, and complications associated with tunneled hemodialysis catheters. MATERIALS AND METHODS: Radiology reports and hemodialysis, medical, and Clinical Information System (computerized patient medical record system) records were retrospectively reviewed in 221 consecutive patients who underwent tunneled hemodialysis catheter placement by interventional radiologists between January 11, 1996 and January 13, 2000 at Dartmouth-Hitchcock Medical Center. Various patient characteristics (diabetes, smoking, hypertension, age, sex, atherosclerotic cardiovascular disease, history of cardiac catheterization, coumadin use, functional status, and obesity) were assessed for their relationship to the outcome of hemodialysis catheters. Catheter outcome was examined by calculating infection rate, thrombosis rate, fibrin formation rate, mechanical malfunction rate, and total complication rate. With these patient characteristics and outcome variables, multiple regression analysis was performed with STATA (College Station, TX) statistical analysis software. RESULTS: Of the 221 patients reviewed, 39 patients were lost to follow-up. Among the remaining 182 patients, 427 catheters were placed for a total number of 36994 catheter-days. For overall complication rate, multiple regression analysis revealed a statistically significant positive correlation only for hypertension (P =.032). Total complication rate was 0.76 events per 100 catheter-days (95% CI: 0.53-1.00) for patients with a documented history of hypertension and 0.27 events per 100 catheter-days (95% CI: 0.08-0.45) for patients without (P =.024, paired student t test). For patients with diabetes versus patients without, the infection rates were 0.34 episodes per 100 catheter-days (95% CI: 0.15-0.53) and 0.12 episodes per 100 catheter-days (95% CI: 0.06-0.18), respectively, (P =.011, paired student t test). Thrombosis rate for patients on coumadin was 0.13 events per 100 catheter-days (95% CI: -0.14-0.40), while thrombosis rate for patients not taking coumadin was 0.03 events per 100 catheter-days (95% CI: 0-0.05) (P =.036, paired student t test). CONCLUSION: Hypertension is a risk factor for poor outcome of tunneled hemodialysis catheters as measured by total complication rate requiring catheter removal or exchange. In this retrospective study, no other specific risk factors predicted an increased need for removal or exchange of tunneled hemodialysis catheters.

Human acyl-coenzyme A:cholesterol acyltransferase 1 (acat1) sequences located in two different chromosomes (7 and 1) are required to produce a novel ACAT1 isoenzyme with additional sequence at the N terminus.

A rare form of human ACAT1 mRNA, containing the optional long 5'-untranslated region, is produced as a 4.3-kelonucleotide chimeric mRNA through a novel interchromosomal trans-splicing of two discontinuous RNAs transcribed from chromosomes 1 and 7. To investigate its function, we express the chimeric ACAT1 mRNA in Chinese hamster ovary cells and show that it can produce a larger ACAT1 protein, with an apparent molecular mass of 56 kDa on SDS-PAGE, in addition to the normal, 50-kDa ACAT1 protein, which is produced from the ACAT1 mRNAs without the optional long 5'-untranslated repeat. To produce the 56-kDa ACAT1, acat1 sequences located at both chromosomes 7 and 1 are required. The 56-kDa ACAT1 can be recognized by specific antibodies prepared against the predicted additional amino acid sequence located upstream of the N-terminal of the ACAT1(ORF). The translation initiation codon for the 56-kDa protein is GGC, which encodes for glycine, as deduced by mutation analysis and mass spectrometry. Similar to the 50-kDa protein, when expressed alone, the 56-kDa ACAT1 is located in the endoplasmic reticulum and is enzymatically active. The 56-kDa ACAT1 is present in native human cells, including human monocyte-derived macrophages. Our current results show that the function of the chimeric ACAT1 mRNA is to increase the ACAT enzyme diversity by producing a novel isoenzyme. To our knowledge, our result provides the first mammalian example that a trans-spliced mRNA produces a functional protein.