The effect of magnesium deficiency on volatile anaesthetic requirement in the rat: the role of central noradrenergic neuronal activity.

Volatile anaesthetic minimum alveolar concentration (MAC, a measure of anaesthetic requirement) increased in a time-dependent manner in rats fed a Mg2+-deficient diet. MAC values in hypomagnesemic rats were 22-30 per cent greater than those in age-matched controls at 12 and 17 days after starting the diet (p < 0.01). Noradrenergic neuronal activity, as assessed from the ratio of the concentration of 3,4-dihydroxyphenylethylene-glycol (DHPG) to that of norepinephrine (NE), decreased in the brain stem and cerebrum-cerebellum in hypomagnesemic rats owing to an increase in NE concentration in both regions of the brain (p < 0.025). We conclude that prolonged hypomagnesemia (> or = 12 days) increases volatile anaesthetic MAC in the rat. The concomitant decrease in the ratio of DHPG/NE suggests that this increase in MAC cannot be attributed to an increase in noradrenergic neuronal activity in brain.     

Poststroke neurogenesis: emerging principles of migration and localization of immature neurons.

Stroke induces proliferation of newly born neurons in the subventricular zone, migration of these immature neurons away from the SVZ, and localization within peri-infarct tissues. These 3 processes of proliferation, migration, and localization constitute distinct spatial and temporal zones within poststroke neurogenesis with distinct molecular and cell-cell signaling environments. Immature neurons migrate after stroke in close association with blood vessels and astrocytic processes, in a process that involves matrix metalloproteinases. This poststroke migration shares similar features with normal neuroblast migration in the rostral migratory stream. Immature neurons localize in the peri-infarct cortex in a neurovascular niche where neurogenesis is causally linked to angiogenesis through the vascular factors SDF-1 and angiopoietin-1. Other vascular and neuronal growth factors have also been linked to poststroke neuroblast localization in peri-infarct tissue, including erythropoietin. Most data on poststroke neurogenesis derive from laboratory rodents, which may have an abnormal or blunted degree of neurogenesis and neuroplasticity compared to normal, wild rodents. This will likely affect translational application of the principles of poststroke neurogenesis from mouse to man.     

Augmentation of cytotoxicity of chemotherapy by human alpha-interferons in human non-small cell lung cancer xenografts

Three human non-small lung cancer xenograft lines were used to study the activity of combinations of cytotoxic drugs with human alpha-interferons (IFNs). Statistically significant potentiation of cis-platinum (CDDP) and cyclophosphamide (CY) given weekly in a low dose was seen when human lymphoblastoid interferon (IFN-alpha nl) (2 X 10(5) mu/mouse/day) was administered simultaneously. The median tumor doubling times for CDDP in the three tumors (35, 22, and 29 days) increased to 52, 51, and 41 days when IFN-alpha nl was added. A similar though less marked effect was seen with CY (median doubling time increased from 21.5, 19.5, and 27 days to 32, 27, and 35 days with the addition of IFN-alpha nl). IFN-alpha nl alone at this dosage was shown to have some cytotoxic activity. Similar potentiation of CDDP and ifosfamide was seen in two tumors when human recombinant alpha-2 interferon was added at a lower dose (2 X 10(4) mu/mouse/day). Median doubling times for CDDP increased from 17 and 14 days to 27 and 18.5 days with the addition of human recombinant alpha-2 interferon, whereas for ifosfamide they increased from 11.5 and 14 days to 15 and 16 days. Human recombinant alpha-2 interferon in this dose had no effect as a single agent.     

Adult neuroblastoma. Report of three cases and review of the literature

Adult neuroblastoma is an uncommon malignancy. The authors report three additional cases and review the 39 reported cases in the world literature. Presentation in the abdomen is the most common; a high rate of lower limb presentation is also observed. Incidence is equal between sexes with median age of presentation of 34 years. Survival is greatest after surgical intervention (median, 20.5 months) compared with no surgery (median, 12.5 months). Chemotherapy may benefit individual patients but does not have a major impact on survival. Radiotherapy is indicated for localized, inoperable primaries or painful metastases. The survival rates of this group of patients parallels that of childhood neuroblastoma, Stage III-IV.