Carcinogenicity of dextran sulfate sodium in relation to its molecular weight

The carcinogenicity of dextran and 3 kinds of dextran sulfate sodium with different molecular weights and almost the same sulfur content were compared in ACI rats. Dextran sulfate sodium of molecular weight 54,000 showed a strong carcinogenic activity when it was given orally as 2.5% diet, whereas dextran sulfate sodium of molecular weight 520,000 and 9500 and dextran showed no significant carcinogenicity, i.e. the peak of carcinogenic activity of dextran sulfate sodium appeared at molecular weight 54,000, and dextran sulfates with larger or smaller molecular weights had no carcinogenic activity.     

Tc-99m HMPAO SPECT imaging of the central nervous system in tuberous sclerosis

Tc-99m HMPAO was used to evaluate cerebral perfusion in a patient with tuberous sclerosis. The SPECT images demonstrated reduced HMPAO uptake in regions corresponding with MRI-confirmed locations of cortical tubers. These results indicate that the lesions are characterized by vascular perfusion deficits and support the hypothesis that cortical tubers result from developmental abnormalities of the embryonic central nervous system.     

Non-target visual event-related potentials in evaluation of children with minor head trauma

In 50 children, 4 months to 12 years of age, with minor head trauma non-target visual event-related potentials were performed and compared to a second registration of the potentials some months later. On following-up there was a clear tendency for a relative improvement of the latencies of the endogenous potentials. In this way non-target visual event-related potentials proved to be of value in the investigation of mental impairment in early childhood.     

Catechol oxidation by peroxidase-positive astrocytes in primary culture: an electron spin resonance study.

In rodents, chronic estrogenization has been shown to induce degeneration of dendrites and myelin figures in the hypothalamic arcuate nucleus adjacent to peroxidase-positive astrocyte processes. Because in this brain region estradiol is metabolized to 2-hydroxyestradiol (catecholestrogen), we hypothesized that the latter may be oxidized by the astrocytic peroxidase activity to cytotoxic ortho-semiquinones as occurs in peripheral tissues. Cysteamine induces nonenzymatic peroxidase activity in cultured astroglia identical to that observed in vivo. Using electron spin resonance, we demonstrate robust peroxidase-catalyzed oxidation of 2-hydroxyestradiol and dopamine by cysteamine-pretreated astrocyte cultures relative to untreated controls. These results implicate the peroxidase-positive astrocytes in the pathogenesis of estradiol-related hypothalamic damage, parkinsonism, and other free-radical-related neurologic disorders.     

Extracellular pH in the brain during ischemia: relationship to the severity of lactic acidosis

On the basis of data showing a bimodal distribution of values for extracellular pH (pHe), and a discontinuous delta PCO2/delta lactate relationship, Kraig et al. (1986) proposed that H+ is grossly compartmentalized between neurons and glia in the ischemic brain. We measured delta pHe during ischemia, varying ischemic lactate contents between 9 and 38 mmol kg-1. No bimodal distribution was found, but delta pHe varied linearly with lactate content. Because we have also failed to record a discontinuous delta PCO2/delta lactate relationship, we conclude that major compartmentation of H+ does not occur during ischemia.     

Pituitary abnormalities in eating disorders: further evidence from MRI studies

1. The frequent occurrence of hypothalamo-pituitary dysfunction in patients with eating disorders as well as prior reports that nutritional and endocrine status influence pituitary morphology, led us to hypothesize that pituitary size and shape may be altered in patients with eating disorders. 2. Magnetic resonance imaging (MRI) does not use ionizing radiation and is currently one of the most feasible modalities available to study the pituitary gland in vivo. Using MRI, we have previously reported in a preliminary study that female patients with eating disorders had significantly smaller pituitary glands than controls. In addition MRI excluded any pituitary mass lesions. 3. In this report, we confirm our previous MRI findings and provide further evidence of pituitary abnormalities in an expanded sample of eating disorder patients. Preliminary data on pituitary volume estimates from MRI scans are provided for a subset of patients and controls.