Multimodality imaging of extra-nodal lymphoma in the head and neck.

Malignant lymphomas represent approximately 5% of all malignant neoplasms of the head and neck. The head and neck region is the second most frequent anatomical site of extra-nodal lymphomas (after the gastrointestinal tract). Most are non-Hodgkin's lymphomas of B-cell lineage, and overall diffuse large B-cell lymphoma is the most common type. They can present in highly variable appearances in different anatomical subsites in the head and neck. There is little literature on their imaging appearances on different imaging methods including ultrasound, magnetic resonance imaging (MRI), computed tomography (CT), and integrated positron-emission tomography (PET)/CT. The review aims to illustrate the presentation of histopathological-proven extra-nodal lymphoma in the head and neck using various imaging methods.

A Chinese patient with non-HFE-linked iron overload.

The gene for hemochromatosis (HFE) was recently identified and contains two missense mutations: C282Y and H63D. The C282Y mutation is found homozygous in approximately 85% to 90% of patients of Northern European ancestry with hereditary hemochromatosis. There are no previous reports with results of genetic testing in Chinese patients with regard to iron overload. In this case report, we describe a Chinese woman with marked hepatic iron overload that was nonfamilial, with unusual biopsy findings, in whom neither the C282Y nor the H63D mutations in HFE were found.

Prolonged storage of frozen unbuffered rapid urease test.

Unbuffered rapid urease test (RUT) is an accurate, rapid, and inexpensive method of detecting Helicobacter pylori. However, it is generally recommended to prepare the reagent daily. This prospective study was undertaken to evaluate the shelf-life of our unbuffered RUT at -20 degrees C. Two sets of antral biopsies (X2) and body biopsies (X1) were taken from all patients. They were subjected to histologic examination and RUT stored at -20 degrees C. We studied 303 patients. One hundred seventy-nine (59%) were infected as defined by histologic examination. The reagent was classified according to the storage time (group I, 0-30 days [n = 109]; group II, 31-60 days [n = 63]; group III, 61-90 days [n = 80]; and group IV, tau91 days [n = 51]). There was an excellent agreement between the histologic examination and the RUT of the four groups (kappa coefficient: group I, 0.88; group III, 0.80; group III, 0.87; group IV, 0.88). The sensitivity of our RUT in groups I, II, III, and IV were 92%, 92%, 91%, and 89%, respectively. The corresponding specificity were 97%, 88%, 97%, and 100%. Our RUT remains highly sensitive and specific when it is stored at -20 degrees C for 4 months.

High alpha-fetoprotein level in HCV-related nodular liver cell dysplasia.

The diagnosis of hepatocellular carcinoma is generally made in patients with a mass lesion in the cirrhotic liver if the alpha-fetoprotein level is >1,000 ng/L. Other causes of elevation of alpha-fetoprotein to this extreme degree include nonseminomatous germ cell tumor and hepatic metastasis. However, it is extremely rare for benign hepatic lesions to cause alpha-fetoprotein of > 1,000 ng/ml. We report a Chinese patient with spontaneous normalization of alpha-fetoprotein with an initial value > 10,000 ng/ml due to nodular dysplasia complicating hepatitis C-related liver cirrhosis. The alpha-fetoprotein was secreted from the dysplastic liver cells.

Cytomegalovirus colitis in individuals without apparent cause of immunodeficiency.

Cytomegalovirus infection is usually reported in immunocompromised patients. In this study, apparently immunocompetent patients with cytomegaloviral colitis were reviewed. Records with a diagnosis of cytomegaloviral colitis from January 1989 to June 1996 were retrieved for analysis. Ten patients were included (median age 70 yr). The major presenting symptoms were diarrhea and hematochezia. Ulceration was the main macroscopic finding. Rectal bleeding was mostly self-limiting. Three patients developed local complications (rectovaginal fistula in two; rectal stricture in one). In the two patients with rectovaginal fistula, lymphocytes subsets and proliferative response were entirely normal. In the other patient, low B lymphocyte count and low response to mitogen were demonstrated. However, the immunoglobulins were not suppressed and rectal biopsies revealed noncaseating granulomas, suggesting activated cell-mediated immunity. In conclusion, a high index of suspicion is crucial for early diagnosis of cytomegaloviral colitis in patients with bloody diarrhea, even though obvious evidence of immunodeficiency is lacking.

Storage temperature of the unbuffered rapid urease test.

OBJECTIVES: The unbuffered rapid urease test (RUT) is an accurate, rapid, and inexpensive method for detecting Helicobacter pylori. However, it is generally recommended that the reagent be prepared daily. This prospective study was undertaken to evaluate the shelf life of our unbuffered RUT when stored at 4 and -20 degrees C. METHODS: Ninety-five patients were studied. Three sets of antral (X2) and body (X1) biopsy samples were taken from each patient. The samples were subjected to histological examination, with the RUTs stored at 4 and -20 degrees C. The RUT tubes were examined at 1 and 15 min. RESULTS: Fifty-six patients (59%) were infected with H. pylori as defined by histological examination. The reagent was classified according to storage time (group I, < or = 5 days; group II, > 5 days). The mean (SD) storage time of group I (n = 59) and group II (n = 36) was 3.2 (1.4) and 9.9 (5.0) days, respectively. At 15 min, the sensitivity of our RUT stored at 4 degrees C was significantly higher in group I than in group II (92 vs 47%). On the other hand, the sensitivity of our RUT stored at -20 degrees C remained consistently high in both groups (15 min: group I, 92%; group II, 100%). Our RUTs stored at 4 and -20 degrees C were highly specific in both groups. CONCLUSIONS: Our RUT remains highly sensitive and specific when it is stored at 4 degrees C for up to 5 days. When the RUT is expected to be stored for a longer period of time, the bottles should be frozen at -20 degrees C.

Lower intestinal hemorrhage due to a dislodged metallic stent.

A case of a 72 year old man is reported who developed a choledochoduodenal fistula due to distal biliary obstruction by a tumor of the papilla. A metal stent, introduced through this fistula into the common bile duct, dislodged and passed spontaneously with the feces. Plastic stents were then successfully inserted.

Shelf life of unbuffered rapid urease test.

BACKGROUND: Unbuffered rapid urease test (RUT) is an accurate and inexpensive method to detect Helicobacter pylori. However, the test is not always readily available because the reagents must be mixed freshly or stored at -20 degrees C after mixing. From our experience, storage at 4 degrees C for less than 6 days seemed to have no effect on the test's accuracy. This prospective study was undertaken to evaluate the shelf life of our unbuffered RUT. MATERIAL AND METHODS: Forty-five patients were studied. From all patients, two sets of antral biopsy (X2) and body biopsy (X1) were taken. One set was subjected to histological examination; the other set was placed into a single capped Eppendorff tube for RUT. The tube was examined for any color change at 1 and 5 minutes. RESULTS: Twenty-six patients (58%) were infected as defined by histological examination. The reagent was classified according to the storage time (group 1, < or = 5 days; group 2, > 5 days). The mean storage times of group 1 (n = 24) and group 2 (n = 21) were 3.1 (1.7 SD) days and 7.7 (1.2 SD) days, respectively. At 1 and 5 minutes, the sensitivity of group 1 was consistently higher than that of group 2 (1 minute, 61% versus 38%; 5 minutes, 92% versus 62%), and no false-positive result was observed in either group. CONCLUSION: RUT remains highly sensitive and specific when it was stored at 4 degrees C for up to 5 days but should be discarded after that period.

Occult gastric cancer presenting as cor pulmonale resulting from tumor cell microembolism.

Cor pulmonale resulting from tumor emboli is a rare presentation of gastric cancer, and only six similar cases have been reported in the English literature. We report the case of a 37-yr-old woman presenting with dyspnea who died of cor pulmonale. Autopsy revealed signet cell carcinoma of te stomach with intra-abdominal metastasis and right ventricular hypertrophy. There were no macroscopic pulmonary emboli or parenchymal lesions, but more than 60% of the small pulmonary arteries and arterioles were occluded. In most vessels, fibrocellular intimal proliferation was the major finding with only a few entrapped tumor cells.

Inhibition of sodium-dependent uptake processes in purified rat brain synaptosomes by Lophozozymus pictor toxin and palytoxin.

To get an insight into the mechanism of neurotoxicity exhibited by Lophozozymus pictor toxin (LPTX) and the toxin isolated from P.caribaeorum (C-PTX) studies were carried out on the effect of these toxins on the uptake of selected substrates (neurotransmitters, amino acids and glucose) in isolated nerve endings. The toxins were found to inhibit the uptake of gamma-aminobutyric acid (GABA), noradrenaline, choline, L-leucine and 2-deoxy-D-glucose in rat brain synaptosomes. LPTX- or C-PTX-induced inhibition of synaptosomal uptake was reduced in the absence of Na+ in the assay medium. Synaptosomes exposed to LPTX and C-PTX release K+ in a dose-dependent manner. Ouabain, a selective inhibitor of the plasma membrane Na+, K(+)-ATPase could inhibit LPTX- and C-PTX-induced K+ efflux from synaptosomes and alleviate the toxin-induced inhibition of synaptosomal GABA uptake. It appears that the induction of ionic flux is the primary cause of toxicity by these toxins leading to the inhibition of Na(+)-dependent uptake processes in synaptosomes. The antagonistic action of ouabain suggests the involvement of the membrane sodium pump in the development of cytotoxicity.

Bioactivity and mechanism of action of Lophozozymus pictor toxin.

The bioactivity of Lophozozymus pictor toxin (LPTX) and the possible mechanism of action of the purified toxin are described. LPTX is found to possess palytoxin-like bioactivities. Besides exhibiting cytotoxic and haemolytic properties, LPTX causes the release of K+ from erythrocytes and inhibits 2-[14C]deoxy-D-glucose uptake into HeLa cells. Although LPTX acts on HeLa cell and erythrocyte membranes, it does not interact with mitochondrial or liposomal membranes containing different phospholipid compositions. Ouabain, but not sphingomyelin, is able to prevent the toxic effects of LPTX. This antagonistic effect of ouabain on LPTX suggests that the toxin might mediate its toxic effects via the membrane Na+/K(+)-ATPase but not through interaction with membrane lipids.