Nifedipine (Procardia XL) as a cause of false-positive results on barium enema study.

There are a number of potential causes for false-positive results on a barium enema study. We report three cases in which patients had to have colonoscopy because a nifedipine slow-release tablet (Procardia XL) was misinterpreted as a colonic polyp on a barium enema study. The pill did not move with abdominal compression, further suggesting that it was a polyp. Patients in whom similar lesions are identified during barium enema examination should be questioned as to whether they are taking these medications.

Gastric syphilis. Report of seven cases and review of the literature.

Gastric syphilis had become an uncommon disease, with only 24 cases reported in the English-language literature over the last two decades. However, it may be becoming more frequent. During the last 4 years, seven patients with gastric syphilis have been diagnosed at our institution. The most common presenting symptoms were abdominal pain, nausea, and vomiting with signs of syphilis present in five patients (71%). After radiographic and/or endoscopic evaluation, the initial diagnosis was considered to be cancer in four patients and nonspecific gastritis in three. The syphilis diagnosis was established by identification of spirochetes on mucosal biopsy in six patients. Although these cases appear typical for gastric syphilis, the diagnosis was usually not considered at first. However, gastric syphilis should be considered in patients at risk for sexually transmitted disease who complain of nausea, vomiting, and abdominal pain and in whom unusual gastric lesions or presumed peptic ulcers resistant to standard therapy are found.

Cell kinetic effects of incorporated 3H-thymidine on proliferating human lymphocytes: flow cytometric analysis using the DNA/nuclear protein method.

Phytohemagglutinin-stimulated human peripheral blood lymphocytes incorporating high concentrations of 3H-thymidine accumulate in G2 and show a consequent reduction in the number of cells entering M (division delay). The simultaneous flow cytometric analysis of DNA content (propidium iodide fluorescence) and nuclear protein content (fluorescein isothiocyanate fluorescence) allows for the accurate quantitation of these events; G2 and M are separated in the bivariate distributions. A good correlation was observed between mitotic indices, quantitated by manually counting mitotic cells, and integration of the M area in DNA/nuclear protein histograms. Moreover, significant differences in G2 nuclear protein levels were found between untreated and 3H-thymidine-treated lymphocytes. In order to characterize this effect, G2 was empirically divided into low nuclear protein (G2A) and high nuclear protein (G2B) compartments. 3H-thymidine caused an initial accumulation of lymphocytes in G2A, followed within 3-6 h by a gradual movement of some cells into G2B, with a subsequent accumulation of cells in G2B. The results suggest that the distribution of cells in G2 (G2A and G2B), the average nuclear protein content of G2B cells, and the proportion of cells in M are parameters that when used in combination provide a unique description of radiobiological effects.

Flow cytometric analysis of RNA content in different cell populations using pyronin Y and methyl green.

Pyronin Y (PY) was used, in flow cytometric (FCM) systems, to estimate the RNA content per cell in formalin fixed EL4 leukosis tumor cells, enzyme dispersed R3327-G rat prostatic adenocarcinoma cells, mouse spleen cells stimulated with concanavalin A, and human peripheral blood lymphocytes stimulated with phytohemagglutinin. Preincubation of the cells with methyl green (MG) blocked PY binding to DNA such that the intracellular fluorescence from MG-PY was due primarily to its binding to RNA. Treatment of the cells with ribonuclease resulted in a 3- to 5-fold reduction in the fluorescence intensity of intracellular MG-PY. Mitogen stimulation of either mouse or human lymphocytes resulted in an increase in DNA (propidium iodide fluorescence) and RNA (MG-PY fluorescence) content per cell over resting levels. Further, the changes in stimulated human lymphocyte DNA and RNA contents following 24, 48, and 72 hr of cell culture were monitored. The results showed that RNA levels were significantly increased prior to that of DNA. Also, the effects of different cell cycle phase specific blocking agents on lymphocyte cell cycle traverse were investigated. We found that: a) actinomycin D inhibited the increases in cellular RNA and DNA; b) hydroxyurea inhibited the increases in cellular RNA were only slightly reduced; c) tritiated thymidine caused an accumulation of cells having high DNA and RNA contents; and d) Colcemid promoted an accumulation of cells having high DNA contents while causing a reduction of cells having high RNA contents. These results were nearly identical to reports by other investigators using the metachromatic dye acridine orange to quantitate RNA per cell. Thus, the MG-PY technique described is indicated to provide a stable and accurate measure of RNA content per cell.