Investigation into the pharmacodynamics of the carcinogen N-nitrodimethylamine

N-Nitrodimethylamine (NTDMA) was found to be a carcinogen of the nasal mucosa leading to aesthesioneuroepitheliomas in BDVI rats. N-Nitromethylamine (NTMA), a product of the oxidative metabolism of NTDMA, was also carcinogenic, leading to neurogenic tumours of the lumbar region of the spine. The 100,000 X g supernatant of both liver and nasal mucosa contains an enzyme capable of reducing NTDMA to N-nitrosodimethylamine (NDMA). In the microsomal fraction of both organs, NTDMA is oxidized to formaldehyde. The fractions from nasal mucosa have a higher capacity than the corresponding liver fractions to both oxidize and reduce NTDMA. NDMA was detected in blood and urine from rats treated with NTDMA. The elimination of NTDMA from blood occurs biphasically, with an initial half-life of 3.5 min.     

Normal perivascular spaces mimicking lacunar infarction: MR imaging

Perivascular (Virchow-Robin) spaces normally surround perforating arteries that enter the medial temporal lobes, corpus striatum, and thalamus. The high soft-tissue sensitivity of magnetic resonance (MR) imaging allows for the frequent detection of such cerebrospinal fluid (CSF)-filled spaces. Especially on axial images, these CSF-filled perivascular spaces may be confused with pathologic lesions, such a lacunar infarcts. Postmortem brain specimens demonstrate the anatomy of perivascular spaces around perforating arteries. Orthogonal images in the living patient help confirm this anatomic relationship. The characteristic CSF signal patterns from these foci are further evidence of their anatomic identification and true benign nature.     

Post-ovulatory ageing of the human oocyte and embryo failure

We carried out a prospective study of 221 healthy women who were attempting pregnancy. During the study, women collected daily urine samples and kept daily records of intercourse. Ovulation and early pregnancy losses were later identified by immunoassays of urinary human chorionic gonadotrophin and steroid metabolites. We have used these data to examine whether the risk of early pregnancy loss was higher with post-ovulatory ageing of the oocyte. 192 pregnancies were ranked by the probability that the oocyte might have aged before fertilization. There was a statistically significant increase in the risk of early loss as the likelihood of oocyte ageing increased (P < 0.05). No similar risk was observed for clinical miscarriages. Post- ovulatory ageing of the oocyte prior to fertilization may cause early pregnancy failure in humans as it does in several other mammalian species.      

Adequate survival of red cells from units "undercollected" in citrate- phosphate-dextrose-adenine-one

The lower limit for the volume of whole blood that may be collected for transfusion into standard blood recipient sets is 405 ml. Each year it is estimated that 82,500 to 161,700 units are drawn which contain between 275 and 405 ml. This study evaluated whether these "undercollected" units would be suitable for transfusion. Twenty normal adults donated both a "standard" unit (450 ml) and an "undercollected" unit (275 ml) in 63 ml of citrate-phosphate-dextrose-adenine-one (CPDA- 1). The units were packed within 4 hours (mean Hct 71%) and stored undisturbed at 4 degrees C for 35 days. Aliquots of 1 to 2 ml of red cells from each unit were then labeled with 51chromium (51Cr) and reinfused into the original donor. The mean 24-hour survival of the 450- ml units was 78.8 percent (SD 12.2, SEM 2.7), while the mean 24-hour survival of the 275-ml units was 87.7 percent (SD 10.7, SEM 2.4; p less than .01). Seven inadvertently undercollected units (mean vol: 295 ml) had a mean 24-hour survival of 91.9 percent. The higher concentration of dextrose and adenine in the undercollected units may improve posttransfusion red cell viability. These data suggest that 275 ml is the minimum acceptable volume for blood donated into CPDA-1.     

Bone Metastasis Revealing Hepatocellular Carcinoma: A Report of Three Cases with a Long Clinical Course

We report herein three cases of hepatoccllular carcinoma revealed by bone metastases. The metastases were located in the skull, the iliac bone, and the femur. The metastases were treated by radiotherapy, and/or surgery. With regard to the liver malignancy itself, two patients were treated by tamoxifen and one by chemo-embolizations. Two patients are alive 27 and 31 months after the first sign, and one died 31 months after the diagnosis. In conclusion, in patients with hepatocellular carcinoma revealed by bone metastases, long survival was obtainable in a few cases, and aggressive treatment could be of interest.     

Meningeal carcinomatosis in the VX2 rabbit tumor model: detection with Gd-DTPA-enhanced MR imaging

Meningeal carcinomatosis developed in 14 of 14 New Zealand White rabbits after infusion of a VX2 tumor cell suspension into the cisterna magna. All died or were killed 7-15 days after inoculation. Within days of the tumor infusion, magnetic resonance (MR) imaging with gadolinium-diethylenetriaminepentaacetic acid (DTPA) at 0.5 or 1.5 T demonstrated enhancement of the cerebrospinal fluid (CSF) secondary to disruption of the blood-CSF barrier by plaquelike lesions along the meninges. Eventually, meningeal enhancement was observed along the base of the brain and cervical spine. Quantitative assessment of the contrast enhancement on T1-weighted images revealed an increase in mean signal intensity of 213% +/- 130%. Contrast enhancement was not observed in four control animals who received an infusion of cell culture medium. These results demonstrate in an animal model that contrast material-enhanced MR imaging can be used to detect meningeal carcinomatosis by revealing breakdown of the blood-CSF barrier.