Increased environmental gamma-ray dose rate during precipitation: a strong correlation with contributing air mass

It has long been observed that the environmental gamma-ray dose rate increases noticeably during precipitation intervals. This increase, due to the presence of radon progeny in the rain droplets (or snow flakes), can affect the reliability of the monitoring of artificial radioactivity and long term estimates of exposure to ambient natural radionuclides in surveillance network. Predicting the amplitude of the dose increase has been shown to be surprisingly challenging. In this work, standard air mass back trajectory analysis is used to show that the amplitude of the increase can be quantitatively linked to the history of the air mass where the precipitation is occurring. Furthermore, we show how back trajectory analysis, environmental gamma and rain data can be used to obtain estimations of relative radon emanation rates for locations far from the actual point of detection.

Murine renal cell carcinoma: evaluation of a dendritic-cell tumour vaccine

OBJECTIVE

To use a murine model of renal cell carcinoma (RCC), Renca, to aid in developing a dendritic cell (DC)-mediated tumour vaccine for RCC; as conventional therapy has been unsuccessful for RCC and therapy using immune modulators has had limited success, novel therapies enhancing further the immune system must be developed.

MATERIALS AND METHODS

DCs were obtained from mouse bone marrow enriched for the haematopoietic progenitors, and cultured in the presence of interleukin-4 and granulocyte macrophage-colony stimulating factor. In vivo vaccines and in vitro proliferation assays were used to assess ability of the DCs to present tumour antigen.

RESULTS

The presence of DCs was confirmed in the cultures by fluorescent-activated cell sorting analysis. In vivo, tumour-bearing animals receiving tumour extract-pulsed DCs as a vaccine showed a two to threefold reduction in tumour growth at day 12 and day 16 but no significant difference at day 28. In vitro, tumour extract-pulsed DCs stimulated significant proliferation of splenocytes from naive animals but not tumour-bearing animals. In addition, splenocytes from tumour-bearing animals had an attenuated immune response in vitro.

CONCLUSION

These results show that it is possible to use the DC vaccine to modulate the immune response to achieve an antitumour effect, but further manipulation of the DC vaccine may be needed to overcome the tumour-induced immune suppression.

Orbital infarction and melting in a patient with systemic lupus erythematosus

OBJECTIVE

To present a patient with systemic lupus erythematosus who developed infarction and melting of the orbit secondary to her systemic disease.

DESIGN

A case report.

PARTICIPANT

A 61-year-old white woman with a 5-year history of systemic lupus erythematosus.

METHODS

The patient presented with left orbital pain, limitation of extraocular movements, and a fistula from the ethmoid sinus to the upper eyelid. A detailed examination with computerized tomography, ultrasound, and a comprehensive medical evaluation with laboratory testing was performed. Histopathologic analysis with special stains of the orbital tissues was also performed.

RESULTS

Histopathologic examination of the biopsy specimens revealed the features of an inflammatory process involving the orbit, similar to a panniculitis. These include a lymphocytic reaction with a predominance of plasma cells, vasculitis with occlusion, and thickening of the vessel walls, necrosis, and hyalinization of fat.

CONCLUSION

This is a unique case in which infarction and melting of the entire orbital structures occurred in the presence of systemic lupus erythematosus. The underlying disease process is a lupus-related panniculitis. The authors stress that this is a very rare entity and that other diseases should be ruled out before entertaining this diagnosis.

Persistent infection of human oligodendrocytic and neuroglial cell lines by human coronavirus 229E

Human coronaviruses (HuCV) cause common colds. Previous reports suggest that these infectious agents may be neurotropic in humans, as they are for some mammals. With the long-term aim of providing experimental evidence for the neurotropism of HuCV and the establishment of persistent infections in the nervous system, we have evaluated the susceptibility of various human neural cell lines to acute and persistent infection by HuCV-229E. Viral antigen, infectious virus progeny and viral RNA were monitored during both acute and persistent infections. The astrocytoma cell lines U-87 MG, U-373 MG, and GL-15, as well as neuroblastoma SK-N-SH, neuroglioma H4, and oligodendrocytic MO3.13 cell lines, were all susceptible to an acute infection by HuCV-229E. The CHME-5 immortalized fetal microglial cell line was not susceptible to infection by this virus. The MO3.13 and H4 cell lines also sustained a persistent viral infection, as monitored by detection of viral antigen and infectious virus progeny. Sequencing of the S1 gene from viral RNA after approximately 130 days of infection showed two point mutations, suggesting amino acid changes during persistent infection of MO3.13 cells but none for H4 cells. Thus, persistent in vitro infection did not generate important changes in the S1 portion of the viral spike protein, which was shown for murine coronaviruses to bear hypervariable domains and to interact with cellular receptor. These results are consistent with the potential persistence of HuCV-229E in cells of the human nervous system, such as oligodendrocytes and possibly neurons, and the virus's apparent genomic stability.

Characterization of the expression and immunogenicity of the ns4b protein of human coronavirus 229E

Sequencing of complementary DNAs prepared from various coronaviruses has revealed open reading frames encoding putative proteins that are yet to be characterized and are so far only described as nonstructural (ns). As a first step in the elucidation of its function, we characterized the expression and immunogenicity of the ns4b gene product from strain 229E of human coronavirus (HCV-229E), a respiratory virus with a neurotropic potential. The gene was cloned and expressed in bacteria. A fusion protein of ns4b with maltose-binding protein was injected into rabbits to generate specific antibodies that were used to demonstrate the expression of ns4b in HCV-229E-infected cells using flow cytometry. Given a previously reported contiguous five amino acid shared region between ns4b and myelin basic protein, a purified recombinant histidine-tagged ns4b protein and (or) human myelin basic protein were injected into mice to evaluate whether myelin-viral protein cross-reactive antibody responses could be generated. Each immunogen induced specific but not cross-reactive antibodies. We conclude that ns4b is expressed in infected cells and is immunogenic, although this does not involve amino acids shared with a self protein, at least in the experimental conditions used.

The immunological basis of nasal polyp formation

Forty-six patients were studied to assess the role of immunological factors in the formation of nasal polyps. Total IgE levels did not correlate with positive skin testing and were generally higher in polyp sac fluid than in corresponding sera. Asthmatics had significantly higher IgE levels in both serum and polyp fluid than nonasthmatics. Specific IgE (RAST) found in polyp specimens could not be detected by conventional skin or serum testing in nine of 15 patients. By direct immunofluorescence IgE was present in 81% of polyp specimens compared with 13% in mucosal controls. These data indicate that nasal polyp formation may be an IgE mediated disease process and conventional skin or serum testing may not detect this local allergic process.