Astrotactin: a novel neuronal cell surface antigen that mediates neuron-astroglial interactions in cerebellar microcultures.

A microculture system for mouse cerebellar cells has been used to identify an immune activity, raised in rabbits against postnatal cerebellar cells, that blocks neuron-glial interactions in vitro. In the presence of blocking antibodies, stable neuron-glial contacts did not form and neuronal induction of glial process outgrowth did not occur. Subsequently, neurons were randomly arranged in the cultures rather than organized along the arms of astroglia. We have named the immune activity that blocks neuron-astroglial interactions anti-astrotactin. Partial purification of the anti-astrotactin blocking antibodies was obtained by cellular absorption with PC12 cells, a clonal cell line which expresses both the N-CAM and NILE (Ng-CAM, L1) glycoproteins. Subsequent absorption with purified cerebellar granule cells, but not with astroglial cells, removed the blocking activity, suggesting that the antigen(s) bound by blocking antibodies are neuronal. Immunoprecipitation of [35S]methionine- or [3H]fucose-radiolabeled Triton extracts of early postnatal cerebellar cells showed that the unabsorbed antiserum recognized a large number of proteins. Among these were bands with apparent molecular masses of N-CAM (180 and 140 kD) and NILE (230 kD). After absorption of the immune serum with PC12 cells, the number of bands recognized by the antiserum was reduced to a prominent band at 100 kD and a diffuse smear of material between 80 and 90 kD. The prominent band at 100 kD was removed by subsequent absorption of the immune serum with granule cells, a step which removed the blocking activity in the cerebellar microculture assay. Further evidence suggests that the astrotactin activity is missing or defective on granule cells from the neurological mutant mouse weaver, an animal that suffers a failure of glial-guided neuronal migration. When anti-astrotactin Fab fragments were pre-absorbed with weaver cerebellar neurons and then tested in the functional assay of neuron-glial interactions, the immune blocking activity was not removed. In contrast, wild-type cerebellar neurons removed the anti-astrotactin blocking activity under the same conditions. Subsequently, when [3H]fucose-radiolabeled Triton extracts of weaver and normal cells were immunoprecipitated with whole or PC12-absorbed anti-astrotactin antiserum, the intensity of the band at 100 kD was reduced by 95% in weaver cells.

Soil surface temperatures reveal moderation of the urban heat island effect by trees and shrubs.

Urban areas are major contributors to air pollution and climate change, causing impacts on human health that are amplified by the microclimatological effects of buildings and grey infrastructure through the urban heat island (UHI) effect. Urban greenspaces may be important in reducing surface temperature extremes, but their effects have not been investigated at a city-wide scale. Across a mid-sized UK city we buried temperature loggers at the surface of greenspace soils at 100 sites, stratified by proximity to city centre, vegetation cover and land-use. Mean daily soil surface temperature over 11 months increased by 0.6 °C over the 5 km from the city outskirts to the centre. Trees and shrubs in non-domestic greenspace reduced mean maximum daily soil surface temperatures in the summer by 5.7 °C compared to herbaceous vegetation, but tended to maintain slightly higher temperatures in winter. Trees in domestic gardens, which tend to be smaller, were less effective at reducing summer soil surface temperatures. Our findings reveal that the UHI effects soil temperatures at a city-wide scale, and that in their moderating urban soil surface temperature extremes, trees and shrubs may help to reduce the adverse impacts of urbanization on microclimate, soil processes and human health.

The effects of ionophore A23187 on erythrocytes. Relationship of atp and 2,3-diphosphoglycerate to calcium-binding capacity.

The divalent cation ionophore, A23187, was employed as a means to load fresh human erythrocytes with calcium, and the capacity for accumulation was characterized. Erythrocytes exposed to A23187 in calcium-containing media rapidly accumulated calcium in millimolar quantities. The final cellular concentration was dependent upon medium calcium concentration and the size of the cellular organophosphate pool. When ATP and 2,3-diphosphoglycerate contents were depleted or repleted, the cellular calcium content changed proportionally. Calcium loading of fresh erythrocytes produced no discernible change in the cellular concentrations of ATP or 2,3-diphosphoglycerate. Calcium accumulation was also accompanied by loss of cellular potassium and H2O, deterioration of cell filterability, and spheroechinocytic transformation.

Selective effects of inhibitors of hormone processing on insulin action in isolated hepatocytes.

Several compounds known to alter receptor-mediated endocytosis were tested for their effect on insulin action in isolated rat hepatocytes. Dansylcadaverine blocked the inhibitory effect of insulin on hepatic protein degradation, but was without effect on the inhibition produced by high concentrations of amino acids. Dansylcadaverine also was without effect on the stimulatory action of insulin on glucose incorporation into glycogen, but totally blocked the insulin stimulation of alanine uptake. No inhibition of basal or (Bu)2cAMP-stimulated alanine uptake was observed with dansylcadaverine. These results indicate that dansylcadaverine has selective effects on some but not all of insulin's actions. Methylamine also blocked insulin stimulation of alanine transport, although at higher doses, methylamine decreased basal and (Bu)2cAMP-stimulated uptake due to cellular toxicity. Chloroquine, an inhibitor of intracellular insulin processing, had no effect on insulin-stimulated alanine transport. To examine the site of action of dansylcadaverine on insulin processing, the binding (cell-associated radioactivity) and degradation of [125I]iodoinsulin by hepatocytes were examined in the presence and absence of dansylcadaverine. Dansylcadaverine delayed the time required to achieve maximal insulin binding and produced a dose-dependent decrease in cell-mediated insulin degradation. Acid dissociation and proteolytic digestion methods were used to differentiate between [125I]iodoinsulin bound to the cell surface vs. that which had been internalized. Dansylcadaverine did not block internalization as measured by either of these criteria, but did block the increase in cell-associated radioactivity produced by chloroquine, suggesting that dansylcadaverine blocks insulin processing after internalization but before the chloroquine-sensitive step. These data show that some of the hepatic actions of insulin, namely inhibition of protein degradation and stimulation of alanine transport, are blocked by certain inhibitors of cellular hormone processing, suggesting that these actions of insulin may require postreceptor events involving insulin metabolism.

Demonstration of a diurnal variation in serum parathyroid hormone in primary and secondary hyperparathyroidism.

It had been reported previously that there is a diurnal variation in serum parathyroid hormone (PTH) in normal subjects but not in patients with primary hyperparathyroidism. Studies were performed to determine whether there is a diurnal variation in serum PTH in primary or secondary hyperparathyroidism and whether the nocturnal increase in serum PTH, if present, could be prevented by induced hypercalcemia. Serum PTH and calcium were measured in five normal subjects, two patients with pseudohypoparathyroidism, and fourteen patients with primary hyperparathyroidism, twelve of whom were subsequently found to have parathyroid adenomas. In the normals, there was a mean decline in serum PTH of 0.07 ng/ml before noon and a mean increase of 0.04 ng/ml after 8 PM. In primary hyperparathyroidism there was a mean decline in serum PTH before noon of 0.11 ng/ml and a mean increase of 0.11 ng/ml after 8 PM. In both groups, the lowest mean serum calcium values were noted between midnight and 6:00 AM. Patients with pseudohypoparathyroidism showed a nocturnal increase in serum PTH. In each of two normal subjects, two patients with primary hyperparathyroidism, and two patients with pseudohypoparathyroidism, calcium, 4 mg/kg body weight per hour for 4 hours (8:00 PM to 12 midnight), produced hypercalcemia and prevented the nocturnal increase in serum PTH. We have concluded that a diurnal variation in serum PTH often occurs in both normal subjects and in patients with primary or secondary hyperparathyroidism and that nocturnal increases in serum PTH can be prevented by induced hypercalcemia.

Methods for solid phase peptide synthesis which employ a minimum of instrumentation.

Both automated and manual methods of solid phase peptide synthesis employ three basic steps: (a) Attachment of the first amino acid to a resin, (b) peptide synthesis via successive carbodiimide couplings and (c) cleavage and deblocking of the peptide. Instead of an automated peptide synthesizer, one can manually synthesize peptides with a sintered glass funnel as the only required piece of equipment. Following solid phase synthesis, one can cleave and deblock peptides without the use of anhydrous hydrofluoric acid (HF); hence, the need for specialized equipment required for handling HF can also be eliminated. In the procedure described in this report, cleavage and deblocking is carried out with trifluoromethane sulfonic acid (TFMSA) in glass vessels without the need for high pressure Teflon fittings. Since completion of the coupling reaction can be monitored during each cycle when manual methods are employed, one can avoid repetitive couplings and, thereby economize on reagents. Since TFMSA cleavage and deblocking can be carried out in open glass vessels, one can cleave and deblock large numbers of peptides at the same time. With the methods described, one can satisfactorily prepare large quantities of peptides at minimal cost.

Influence of diagnostic radioiodines on the uptake of ablative dose of iodine-131.

The uptakes of thyroablative doses of 131I by postoperative thyroid remnants and/or thyroid carcinoma metastases following diagnostic surveys with 131I or 123I were retrospectively compared by visual inspection. Only those patients with a diagnostic scan demonstrating functioning tissue, remnant, and/or metastasis, following thyroidectomy for differentiated thyroid carcinoma, were evaluated. The 131I survey group (n = 26) had received a diagnostic dose of 3 to 10 mCi of 131I. The 123I group (n = 14) had received the usual diagnostic dose of 300 microCi of 123I. The age, sex, and tumor type in the two groups were not statistically different. The uptake of the ensuing thyroablative dose of 131I appeared, by visual inspection, to be impaired in 20 of 26 patients in the 131I group and in none of the 14 patients in the 123I group (p < 0.00003). In the 131I group there was suggestion of a dose-response, that is, the higher the administered activity of 131I for the diagnostic scan, the more reduced was the subsequent apparent uptake of the thyroablative dose (p = 0.0007). Thyroid remnants or cervical lymph node metastases appeared to be affected more frequently than were the distant (pulmonary or skeletal) metastases (p = 0.004). This study suggests that iodine uptake function may be suppressed by the absorbed radiation from the 3 to 10 mCi "diagnostic" scanning dose of 131I. In this regard, 123I may be a better initial diagnostic agent to be used prior to radioablation therapy.

Life-threatening hypercalcemia associated with primary hyperparathyroidism during pregnancy: case report and review of literature.

OBJECTIVE: To report a case of life-threatening hypercalcemia attributable to primary hyperparathyroidism in a pregnant patient and discuss the management of severe hypercalcemia during pregnancy. METHODS: We describe a 28-year-old pregnant woman who had life-threatening hypercalcemia (serum calcium level of 25.8 mg/dL). Primary hyperparathyroidism was diagnosed. The patient's management and the published medical literature on primary hyperparathyroidism during pregnancy are reviewed. RESULTS: Our patient had the highest reported serum calcium level that we could find attributable to primary hyperparathyroidism during pregnancy. After initial stabilization, parathyroidectomy was successfully performed during pregnancy. To our knowledge, this is the first report in which this profound degree of hypercalcemia did not result in an adverse maternal or fetal outcome. CONCLUSION: Although uncommon, primary hyperparathyroidism during pregnancy may be associated with severe maternal and perinatal complications. Life-threatening hypercalcemia due to primary hyperparathyroidism during pregnancy can be successfully managed surgically during pregnancy, with good maternal and fetal outcome.

Monoclonal antibodies to periodontal ligament cells.

Ten mouse monoclonal antibodies were prepared against cultured bovine periodontal ligament cells to be used as reagents for the study of periodontal disease and wound healing. Using standard immunohistochemical methods, these antibodies were found to recognize cell surface antigens in formalin-fixed bovine periodontium. Three of the 10 monoclonal antibodies (i.e., PDL-1, PDL-2, and PDL-10) cross-reacted with cells found in primate periodontium. While the isolated monoclonal antibodies appeared to distinguish subpopulations of cells located in the supporting tissues of teeth, immunohistological examination of other organs (dermis, kidney, skeletal muscle, thyroid, and parotid gland) indicated that a number of cell types of mesenchymal origin share an antigen(s) found on periodontal cells. The monoclonal antibodies described in this report should prove to be useful in studies of periodontal disease and guided tissue regeneration by providing both analytical reagents and immunochemical methods for isolating selected cell populations of the periodontium.

Disconnected phonology: a linguistic analysis of phonemic jargon aphasia.

This paper reports on indications of the nature of the neurolinguistic connection between phonological and lexical components of language, based on a case of phonemic jargon aphasia. Following bihemispheric embolic infarcts, the subject presented with severe fluent aphasia, characterized by fluent strings of phonemes, with virtually no intelligible utterances. Despite nearly total jargonized output, the fundamental phonological processes of speech were largely intact. Specifically she demonstrated: (1) English phonotactics and English stress-timed rhythmic principles, (2) aspirated stops word-initially and glottalized stops word-finally, (3) utterance final declination of pitch, and (4) stressed syllable vowel lengthening. Additionally, regional-specific (Southern American English) phonological processes, including monophthongization, in-gliding, and front vowel backing, were also preserved. Overall, the investigation reveals an example of an intact phonological rule system operating on a grossly disturbed input (lexical representation).

Acoustic analysis of affective prosody during right-sided Wada Test: a within-subjects verification of the right hemisphere's role in language.

A within-subjects study of the affective characteristics of voice was carried out in patients undergoing a Wada Test (WT). All patients became densely aphasic after the left-sided WT and lost the ability to impart affect into speech after the right-sided WT. The affective changes in voice induced by the Wada test were acoustically analyzed by computer-assisted techniques and compared to data obtained pre-Wada and post-Wada. The statistical results, using a one-way analysis of variance for repeated measures, confirmed robustly the current view that the right hemisphere modulates dominantly the affective components of language. The results are also evaluated in light of recent clinical and acoustical data regarding the organization of language in speakers of tone languages, thus, allowing the authors to address issues concerning universal principles of brain-language-behavioral relationships.

Feasibility of low doses of I-131 for thyroid ablation in postsurgical patients with thyroid carcinoma.

The feasibility of using low doses of I-131 (30 mCi) for ablation of thyroid remnants following surgery for papillary and follicular thyroid carcinoma was examined in 21 patients. Six weeks following near-total thyroidectomy and three days following intramuscular thyroid-stimulating hormone (10 IU), patients were given 30 mCi of I-131 and scans were performed 24 to 72 hours later. Remaining thyroid tissue was identifiable in the thyroid bed in 19 patients, and two patients also had evidence of cervical metastases. Patients with metastases received an additional 100 mCi of I-131. Follow-up I-131 scans were performed at nine to 15-month intervals in ten patients who initially received 30 mCi of I-131, and only one patient showed complete ablation of the residual thyroid tissue, whereas the remaining nine patients had persistent uptake of I-131 in the same regions in which the uptake was seen in the initial postoperative scans. One of the nine patients had evidence of a cervical metastasis as well. It is therefore apparent that total or near-total thyroidectomy rarely removes all thyroid tissue and that an "out-patient" dose of I-131 is not adequate for ablation of postoperative thyroid remnants.

The legacy of nitrogen pollution in heather moorlands: ecosystem response to simulated decline in nitrogen deposition over seven years.

Eutrophication and acidification of heather moorlands by chronic atmospheric nitrogen (N) pollution, is of major concern within these internationally important ecosystems. However, in the UK and Western Europe generally emissions of NO(y) and NH(x) peaked during the 20th century. Due to the history and scale of atmospheric N pollution, the legacy of these high levels of N deposition, through accumulation in soil, may hinder or prevent ecosystem recovery. Effects of N pollution on heather moorland were investigated throughout the ecosystem including; the dominant plant species, Calluna vulgaris, the bryophyte and lichen community and the soil system using a long-term experiment simulating wet N deposition. We observed an increase in C. vulgaris height, shoot extension and canopy density, litter mineral N, total N concentration, N:P and C:N ratios in response to N addition. Bryophyte species diversity, bryophyte and lichen frequency and the frequency of two individual bryophyte species (Lophozia ventricosa and Campylopus flexuosus) were significantly reduced by N addition. We developed an N recovery experiment, using a split-plot design, on the long-term N treatment plots to investigate ecosystem response to a simulated decline in N deposition. Two years after cessation of N treatment the only ecosystem component that responded to the recovery experiment was C. vulgaris shoot extension, however after seven years of recovery there were significant declines in litter total N concentration and mineral N and an increase in litter C:N ratio. Although bryophytes and lichens form a close relationship with atmospheric N deposition these organisms did not show a significant response to the N recovery experiment, two years after cessation of N treatment. These data indicate that low nutrient ecosystems, such as moorlands, have the capacity to respond to declines in N deposition however the accumulation of pollution may hinder recovery of sensitive organisms, such as bryophytes and lichens.

Bio-indicators of nitrogen pollution in heather moorland.

Heather moorlands are internationally important ecosystems that are highly sensitive to eutrophication and acidification by reactive atmospheric nitrogen (N) deposition. We used a long-term experiment simulating wet-deposition of N on heather moorland to identify potential bio-indicators of N deposition. These indicators were subsequently employed in a survey covering a N deposition gradient ranging from approximately 7 to 31kg N ha(-1) yr(-1), at selected sites throughout the UK. In this regional survey litter phenol oxidase activity and bryophyte species richness were negatively associated with N deposition. Calluna vulgaris N:P ratios and litter extractable N were positively correlated with N deposition. The use of the suite of four bio-indicators has the potential to provide rapid assessment of the extent of N saturation of heather moorland sites and moorland ecosystem functioning, and has significant advantages over reliance on single measures such as soil N status or an individual bio-indicator species.

Alfven waves in the solar corona.

Alfvén waves, transverse incompressible magnetic oscillations, have been proposed as a possible mechanism to heat the Sun's corona to millions of degrees by transporting convective energy from the photosphere into the diffuse corona. We report the detection of Alfvén waves in intensity, line-of-sight velocity, and linear polarization images of the solar corona taken using the FeXIII 1074.7-nanometer coronal emission line with the Coronal Multi-Channel Polarimeter (CoMP) instrument at the National Solar Observatory, New Mexico. Ubiquitous upward propagating waves were seen, with phase speeds of 1 to 4 megameters per second and trajectories consistent with the direction of the magnetic field inferred from the linear polarization measurements. An estimate of the energy carried by the waves that we spatially resolved indicates that they are too weak to heat the solar corona; however, unresolved Alfvén waves may carry sufficient energy.

Tissue reaction to an implantable identification device in mice.

Long-term toxicity and carcinogenicity studies require positive identification of animals. Due to the unreliability of traditional methods, it was necessary to investigate more dependable identification methods that can be read directly or by electronic means. A two-year study to determine the stability of and tissue reaction to a microchip glass-sealed device implanted in subcutaneous tissue of mice was conducted. Seventy B6C3F1 mice of each sex were anesthetized and implanted with the microchip. The devices were read by an electronic detector and palpated at periodic intervals. Ten mice of each sex were necropsied at 3 months and at 15 months with the remaining animals necropsied at 24 months. Of the 140 devices implanted, 3 were lost and 4 failed during the 24-month study. Devices were palpable and appeared to be fixed at one location with no obvious swelling due to inflammation or palpable masses around the implants for 24 months. At the 3, 15, and 24 month necropsies, implants were encapsulated by connective tissue. Light microscopic evaluation indicated that the capsule around the implants was thin and composed of fibrocytes and mature collagen fibers, with minimal to mild inflammation and occasional granulomatous reaction. Neoplastic changes were not observed in the tissue around the glass-sealed devices with polypropylene cap for up to 24 months.