Observer agreement on interpreting colposcopic images of CIN

The purpose of this work was to study intraobserver and interobserver variation in the interpretation of colposcopic images of cervical intraepithelial neoplasia (CIN). Twenty-three experienced colposcopists were asked to assess colposcopic images presented on slides and to select the biopsy site. Eleven cases were independently interpreted twice with an interval of 2-3 months by all observers. No information about the cytological classification was available. In each case the "majority assessment" was considered as the standard, being "no CIN" in 2 cases, CIN I in 4 cases, CIN II in 3 cases, and CIN III in 2 cases. Intraobserver concordance was 66.7%, the kappa value was 0.54. Interobserver agreement was found to be 52.4 and 51.0% in the first and second sessions, respectively, while the mean kappa values were 0.41 and 0.33, respectively. In selecting the site for biopsy, 77.4% of all observers agreed while the same site was selected in 85.3% of cases by the individual colposcopist in the two sessions. Overall, CIN I and II interpretations revealed lower levels of agreement than no CIN or CIN III interpretations. It is concluded that observer variability in interpreting colposcopic images and selecting the site for biopsy is in the same range as observer variation in other subjective diagnostic tests such as cytology and histopathology. This variation should be taken into account in the colposcopical management of patients with abnormal cytology.     

Cellular mechanisms for developmental toxicity of chlorpyrifos: targeting the adenylyl cyclase signaling cascade

Developmental neurotoxicity caused by chlorpyrifos exposure is generally thought to target cholinesterase but chlorpyrifos may also act on cellular intermediates, such as adenylyl cyclase, that serve global functions in the coordination of cell development. In the current study, neonatal rats were exposed to apparently subtoxic doses of chlorpyrifos (no weight loss, no mortality) either on Postnatal Days 1-4 or on Postnatal Days 11-14, and the effects on components of the adenylyl cyclase cascade were evaluated in brain regions that are enriched (forebrain) or sparse (cerebellum) in cholinergic innervation, as well as in a nonneural tissue (heart). In all three, chlorpyrifos evoked deficits in multiple components of the adenylyl cyclase cascade: expression and activity of adenylyl cyclase itself, functioning of G-proteins that link neurotransmitter and hormone receptors to cyclase activity, and expression of neurotransmitter receptors that act through this cascade. Disruption of signaling function was not restricted to transduction of cholinergic signals but rather extended to adrenergic signals as well. In most cases, the adverse effects were not evident during the immediate period of chlorpyrifos administration, but appeared after a delay of several days. These results suggest that chlorpyrifos can affect cell development by altering the activity and reactivity of the adenylyl cyclase signaling cascade, a major control point for trophic regulation of cell differentiation. The effects are not restricted to cholinergic targets, nor even to the central nervous system. Hence, disruption of cell development by chlorpyrifos is likely to be more widespread than previously thought.     

Prospective, randomized trial of prolonged intracoronary urokinase infusion for chronic total occlusions in native coronary arteries

OBJECTIVES: The purpose of this study was to determine the safety and efficacy of three dosing regimens of intracoronary urokinase for facilitated angioplasty of chronic total native coronary artery occlusions. BACKGROUND: Percutaneous transluminal coronary angioplasty of chronically occluded (>3 months) native coronary arteries is associated with low initial success secondary to an inability to pass the guide wire beyond the occlusion. METHODS: Patients were enrolled if a chronic total occlusion >3 months old could not be crossed with standard angioplasty equipment. Of the 101 patients enrolled, 41 had successful guide wire passage and were excluded from urokinase treatment. The remaining 60 patients were randomized to receive one of three intracoronary dosing regimens of urokinase over 8 h (group A = 0.8 million U; group B = 1.6 million U; group C = 3.2 million U), and angioplasty was again attempted after completion of the urokinase infusion in 58 patients. RESULTS: Coronary angioplasty was successful in 32 patients (53%) (group A 52%, group B 50%, group C 59%, p = 0.86). This study had a 90% power to detect at least a 50% difference between dosing groups at alpha 0.05. Bleeding complications requiring blood transfusion did not differ significantly among the dosing groups (A 0%, B 15%, C 6%, p = 0.14), although major bleeding episodes were less common in group A (p < 0.05). There were no major procedural or in-hospital complications. Angiographic follow-up in 69% of the patients with successful angioplasty revealed target vessel patency in 91% but an angiographic restenosis rate of 59%. CONCLUSIONS: A prolonged supraselective intracoronary infusion of urokinase can be safely administered and may facilitate angioplasty of chronic total occlusions. Lower doses of urokinase are equally effective and result in fewer bleeding complications than do higher dosage regimens. Vessel patency is frequently maintained, but restenosis remains a problem.     

Effects of the glucocorticoid agonist, RU28362, and the antagonist RU486 on lung phosphatidylcholine and antioxidant enzyme development in the genetically obese Zucker rat

The biochemical maturation of the lung in late gestation and in the young animal is regulated by glucocorticoids. The present study was aimed at dissociating the different glucocorticoid receptor sites involved in these regulatory functions. The obese Zucker rat was selected as a model for this study as it exhibits hypersensitivity to glucocorticoid hormone action by virtue of its elevated receptor numbers and activity. Two synthetic steroid analogues were administered to obese animals; RU28362, a specific type II receptor agonist, and the type II antagonist RU486. RU28362 promoted a strong catabolic effect, which was associated with reduced food intake and the abolition of growth in the rats. The agonist, RU28362, attenuated developmental increases in antioxidant enzyme activities, and altered the growth of the tissue. At the age studied, development of the lung phosphatidylcholine (PC) system was almost complete, but RU28362 increased disaturated PC 16:0/16:0 concentrations by almost 2-fold, and altered the molecular composition of total pulmonary PC. RU486 attenuated the growth of the rats and reduced their food intake. Treatment with the type II antagonist attenuated lung growth and increased the activities of pulmonary copper zinc (Cu/Zn) and manganese (Mn) superoxide dismutases. RU486 had no effect on lung PC concentrations and molecular composition. The data suggest a role for type I glucocorticoid receptors in the regulation of the antioxidant enzyme system in the lung, as type II antagonism will channel endogenous glucocorticoid binding to the type I site. Type II receptor binding would appear to play a role in regulating the lung PC content.     

Variable presentation of cerebrovascular disease in monovular twins

We describe twin girls with bilateral cerebrovascular disease. In one child, a diagnosis of moyamoya disease was made after presentation in infancy with an acute hemiparesis; her asymptomatic sibling was found to have significant bilateral cerebrovascular disease after neuropsychological evaluation and assessment with transcranial Doppler ultrasound. Both subjects showed a discrepancy between verbal and performance IQ and deficits on a test of frontal-lobe function suggesting that these domains should be targeted in cognitive assessment. Family members of subjects with moyamoya are at risk of cerebrovascular disease. Clinical symptoms do not reliably predict disease and those at risk should be offered screening with non-invasive vascular imaging.     

Regional and cellular expression of glial (GLT1) and neuronal (EAAC1) glutamate transporter proteins in ovine fetal brain

Glutamate transport is a primary mechanism for regulating extracellular levels of glutamate which can have either neurotrophic or neurotoxic effects in the developing brain, depending on its concentration. Using immunoblotting and immunocytochemistry, we tested the hypotheses that expression of neuronal and glial glutamate transporter proteins was regionally and temporally regulated in the developing ovine brain and that expression of the glial isoform early in development was not cell-type specific. Immunoblots for the neuronal glutamate transporter EAAC1 revealed a major band of immunoreactivity at 69,000 nmol. wt, whereas glial glutamate transporter-1 (GLT1) immunoreactivity was observed as 73,000 and 146,000 mol. wt proteins. EAAC1 and GLT1 are regulated differently during development, with EAAC1 immunoreactivity being most abundant at 60 and 71 days completed gestation (term=145 days) and dissipating thereafter, while GLT1 immunoreactivity was most abundant at 136 days gestation. By immunocytochemistry EAAC1 expression is neuronal throughout gestation with intense labelling of dendrites within the telencephalon evident at 60 days. Neuropil, neuronal cell bodies and processes are EAAC1-immunoreactive throughout gestation with no evidence of astrocytic or oligodendroglial immunoreactivity. In contrast, GLT1 is expressed by neuronal and non-neuronal cell types during midgestation with astrocyte selectivity developing by 136 days. During midgestation, GLT1 is transiently expressed in neurons of the subplate, cranial nerve nuclei, basal ganglia, and cerebellar cortex. The major finding of this study, that GLT1 is transiently expressed in various neuronal populations at midgestation demonstrates that the cell-type specificity of the GLT1 phenotype is developmentally regulated and depends on brain maturity.     

Modeling the developmental neurotoxicity of chlorpyrifos in vitro: macromolecule synthesis in PC12 cells

Exposure to apparently subtoxic doses of chlorpyrifos during late stages of brain development affects cell acquisition through a mixture of cholinergic and noncholinergic mechanisms. In the current study, we modeled these effects in vitro using rat pheochromocytoma (PC12), a cell line that, upon nerve-growth factor (NGF)-induced differentiation, develops the appearance and function of cholinergic target neurons, including the expression of cholinergic receptors. In the undifferentiated state (no NGF), chlorpyrifos evoked an immediate (1 h), robust, concentration-dependent inhibition of DNA synthesis as evaluated by [3H]thymidine incorporation, with a threshold of 0.5-1.5 microg/ml. Continuous exposure for up to 24 h maintained the same degree of inhibition. The effects were selective for DNA synthesis, as much smaller inhibitions were found for synthesis of RNA or protein. In contrast, direct cholinergic stimulation of the cells by 100 microM nicotine had much smaller effects on DNA synthesis. Moreover, the effects of chlorpyrifos on DNA synthesis could not be blocked by nicotinic or muscarinic antagonists, confirming that the effects were not mediated primarily through cholinergic hyperstimulation consequent to cholinesterase inhibition or to direct receptor-mediated effects. When PC12 cells underwent NGF-induced differentiation, the rate of cell replication fell dramatically and neurite extension was evident both from morphological examination and from biochemical markers (increased protein:DNA ratio). After introduction of NGF, chlorpyrifos maintained its ability to inhibit DNA synthesis acutely. However, the ability to inhibit RNA and protein synthesis initially intensified and then disappeared, indicating a shift in macromolecular targets as differentiation proceeded. We also tested the effects of long-term exposure to chlorpyrifos during the process of NGF-induced differentiation. Continuous chlorpyrifos exposure resulted in severe reductions in macromolecule synthesis and a deficit in the total number of cells, effects similar to those seen with chlorpyrifos treatment in vivo. At the highest concentrations, neurite extension was also inhibited. Our results suggest that chlorpyrifos can interact directly with developing neural cells to inhibit replication and neuritic outgrowth.