Establishment of a human acute promyelocytic leukemia-ascites model in SCID mice

Acute promyelocytic leukemia (APL) is an interesting model for cancer research because of the presence of the specific PML-RARalpha fusion gene associated with the clinical response to retinoic acid differentiation therapy. To better understand and improve differentiation induction with retinoic acid, we have established a human APL-ascites model in SCID mice using the NB4 human APL cell line. NB4 (1 x 10(6) cells) were transplanted into the peritoneum (IP) of SCID mice for 1 month. NB4 ascites cells (A-NB4) appeared, which were then engrafted in SCID mice periodically for 18 passages at an interval of 3 to 4 weeks with a 100% success rate of tumor induction. The mean survival times of SCID mice transplanted with 1 x 10(6) A-NB4 cells was 21.6 +/- 2.3 days. Analysis of the biologic characteristics of ninth passage NB4 ascitic cells was performed and they were found to have the morphologic, immunologic, cytogenetic, and molecular features of cultured NB4 cells. Furthermore, A-NB4 cells were capable of differentiating when treated with all-trans retinoic acid (ATRA), as manifested by enhanced NBT reduction and CD11b expression. In vivo treatment with ATRA in SCID mice for 4 days also increased NBT reduction by A-NB4 cells. ATRA treatment significantly prolonged survival time in the group after transplantation (28.1 +/- 6.8 to 29.1 +/- 8.4 days) compared with the control (P < .001). Furthermore, treatment with adriamycin, an effective chemotherapeutic drug in APL, had a strong growth suppressive effect on A-NB4 cells. These results demonstrate that this SCID-APL (NB4 ascites cells) model is a useful preclinical system for evaluating new or known drugs in the treatment of APL.     

Spinal cord compression–do we miss it?

Four children with spinal cord compression due to malignant tumours are presented. The severity of the condition was not initially recognized by parents, or the nature of the likely cause by the initial physicians. Lower limb asymmetrical weakness, clear-cut sensory levels, and marked pain indicate need for urgent imaging and exclusion of a space occupying lesion. In 1997 diagnosis of Guillain-Barré syndrome should not be made without careful prior spinal imaging.     

Distribution of substance P-like immunoreactivity in the goldfish brain

Immunohistochemical methods were used to study the distribution of SP-like immunoreactivity (SPLI) in the brain of the common goldfish (Carassius auratus). SPLI cell bodies and fibers were seen in distant areas and nuclei throughout the brain. In the telencephalon, SPL1 was found in the area dorsalis telencephali pars centralis and pars lateralis, areas that have been compared to the basal ganglia of land vertebrates. In the diencephalon, SPLI somata were seen in the hypothalamus. Four primary visual centers contained SPLI fibers: the nucleus of the posterior commissure, the area pretectalis, the nucleus dorsolateralis thalami and the optic tectum; the origin of these fibers could not be determined. SPLI cell bodies were seen in the oculomotor nucleus; the possibility that this may be the Edinger-Westphal nucleus is discussed. A high density of immunoreactive fibers was seen in the tractus retroflexus and the interpeduncular nucleus, though the habenula showed a few SP-like immunopositive fibers. In the hindbrain, SPLI cell bodies and fibers were seen in the nuclei ambiguus and commissuralis of Cajal and in the dorsal motornucleus of the vagus nuclei; even though these nuclei are known to belong to the visceral and sensory motor columns, the exact role SP plays in processing this information is at present unknown.     

Outpatient lumbar myelography. Initial results in 79 examinations using a low-dose metrizamide technique

Seventy-nine patients underwent lumbar myelography on an outpatient basis, with a low (3.75 g) dose of metrizamide as the radiocontrast agent and a 25-gauge spinal needle used for lumbar puncture. No patient experienced significant neurotoxicity following the examination; 70.8% (56 of 79) experienced minimal (23%) or no (48%) side effects. Three patients (3.8%) were admitted to the hospital for management of common side effects (headache, nausea/vomiting, back pain). We obtained postmyelographic computed tomographic scans on 96% (76 of 79) of the patients. Our initial results suggest that outpatient lumbar myelography is safe and can be performed with a very acceptable incidence of side effects.