Upper limit on the diffuse flux of ultrahigh energy tau neutrinos from the Pierre Auger Observatory

The surface detector array of the Pierre Auger Observatory is sensitive to Earth-skimming tau neutrinos that interact in Earth's crust. Tau leptons from nu(tau) charged-current interactions can emerge and decay in the atmosphere to produce a nearly horizontal shower with a significant electromagnetic component. The data collected between 1 January 2004 and 31 August 2007 are used to place an upper limit on the diffuse flux of nu(tau) at EeV energies. Assuming an E(nu)(-2) differential energy spectrum the limit set at 90% C.L. is E(nu)(2)dN(nu)(tau)/dE(nu)<1.3 x 10(-7) GeV cm(-2) s(-1) sr(-1) in the energy range 2 x 10(17) eV< E(nu)< 2 x 10(19) eV.

Secondary retinal changes associated with choroidal naevi and melanomas documented by optical coherence tomography

AIMS

To establish the characteristics of secondary retinal changes associated with the presence of choroidal melanomas and choroidal naevi as documented by optical coherence tomography (OCT).

METHODS

Twenty patients with untreated choroidal melanoma and 40 patients with presumed choroidal naevi managed by regular observation were included in the study. OCT scans across the surface of the tumour and surrounding tissue were acquired for all participants. The appearance of retinal tissue on the OCT scans was considered to be abnormal if it did not display the well defined band structure characteristic of normal tissue on OCT scans.

RESULTS

Serous retinal detachments were observed in all patients with choroidal melanoma and 18 out of 20 also had abnormal retinal structure or intra-retinal splitting in the tissue overlying the tumour. Out of the 40 patients with presumed choroidal naevi, 12 had serous detachments and three had either abnormal retinal structure or intra-retinal splitting overlying the lesion.

CONCLUSIONS

Secondary retinal changes associated with choroidal lesions can be documented by OCT. These changes were observed in most patients with choroidal melanoma included in the study group but were far less prevalent in the patients with presumed choroidal naevi. OCT is also able to identify the presence of small serous detachments before they become clinically visible. Follow up of these patients is required to determine whether the OCT results may be of use in the differential diagnosis of small choroidal lesions.

Improved survival rates in sebaceous carcinoma of the eyelid

PURPOSE

To review the clinicopathological features, management, and survival rates for patients with sebaceous gland carcinoma of the eyelid, and to analyse the reasons for improved survival.

METHODS

In the west of Scotland between 1975 and 2001, 32 cases were identified through the pathology index for sebaceous carcinoma. Pathology specimens were reviewed in all cases. The clinical data were obtained from hospital records and the database provided by the Regional Cancer Registry.

RESULTS

A total of 22 female and 10 male patients were identified. Follow-up ranged from 6 months to 15 years, median of 4.8 years. Primary treatment involved excisional techniques in 27 cases, exenteration in two cases, enucleation in two cases, and two cases required adjuvant radiotherapy. Intraepithelial spread and masquerade presentations delayed the diagnosis. Poorly differentiated tumours were associated with an unfavourable outcome. Three patients developed local tumour recurrence and one metastatic disease. In all, 10 patients died from nontumour-related causes and one died from metastatic sebaceous carcinoma. The overall tumour mortality rate in the west of Scotland was 3%.

CONCLUSIONS

From this study, patients in the west of Scotland have a better prognosis than is indicated in the literature. Astute clinical suspicion and accurate histopathological diagnosis, together with radical and aggressive surgical approaches were key factors.

Optical coherence tomography in the diagnosis of subclinical serous detachment of the macula secondary to a choroidal nevus

We present a case in which optical coherence tomography (OCT) aided in the diagnosis of subretinal fluid (SRF) secondary to a choroidal nevus. A patient with a raised lesion above the left optic disc and distorted central vision was referred to our unit because of suspected choroidal melanoma. Fundus fluorescein angiography and slit-lamp investigation did not indicate any areas of SRF; however, OCT showed serous detachment in the macular area. The lesion was treated with laser photocoagulation and, when reviewed at four weeks post-treatment, repeat OCT scans showed that the area of SRF had cleared. In this case OCT was able to detect a subclinical serous detachment in the macula. This may have important implications in the monitoring of patients with small suspicious lesions.

High-dose stabilized chlorite matrix WF10 prolongs cardiac xenograft survival in the hamster-to-rat model without inducing ultrastructural or biochemical signs of cardiotoxicity

WF10 is a stabilized chlorite matrix with immunosuppressive effects. In vitro studies have demonstrated its ability to suppress T cells and delay or abolish antigen presentation. Hence, WF10 may prove useful to prolong graft survival after transplantation. In this study, we evaluated the use of high dose WF10 as a single drug regimen in the hamster-to-rat xenotransplantation model and searched for possible cardiotoxic side effects. WF10 prolonged cardiac xenograft survival, but did not induce tolerence or inhibit pathological signs of acute rejection. Hamsters from the donor population, receiving high dose WF10 for 5 days, were compared with a matched control group. Ultrastructural examination of cardiac tissue as well as biochemical analysis of the cardiac enzymes troponin I, myoglobin and MB isoenzyme of creatine kinase showed no signs of damage. Thus, while prolonging graft survival, high dose WF10 seems to be non-cardiotoxic and as such should not contribute to the differential diagnosis of acute graft failure.

Retinal vasoproliferative tumors: surgical management and histological findings

Vascular masses occurring in the peripheral retina have been described extensively in the literature. Many terms, including "presumed acquired hemangiomas," "hemangioma-like," "angiomatous masses," "angioma-like," "peripheral retinal telangiectasis," and "vasoproliferative tumors," have been suggested that reflect the lack of the known histological features and the potentially variable causes. We describe the histological features of 2 patients who underwent transcleral local resection as management for suspected choroidal melanoma. Pathological examination of these tumors reveals the constituents to be primarily benign glial cell proliferation with secondary vasoproliferation. The weight of the literature agrees with a reactionary process. We therefore suggest the term "reactionary retinal glioangiosis." Transcleral resection has a place where diagnosis is difficult. It prevents an unnecessary enucleation and allows accurate tissue diagnosis.

Effect of leflunomide and cyclosporine on graft survival and changes in lymphocyte phenotypes in a rat heart allotransplantation model

Cyclosporine-A (CSA) and leflunomide (LF) can delay or prevent organ graft rejection. We investigated the combination of LF, CSA and splenectomy on graft survival and changes in lymphocyte phenotypes (LP) in a rat allotransplantation model. In the study 19 Lewis rats were splenectomized prior to heterotopic heart transplantation. SPRD rats served as donors. The recipients were divided into three groups: A--five animals received CSA and LF for two weeks, B--five received intermittent CSA and LF for the whole investigation period and C--nine received no drug therapy. LP was quantified relatively by flow cytometric analysis. We found that graft survival was longer in group A (median 155 days, range 52-348) and B (341, range 338-342), compared to group C (8, range 7-13). The histological examination, however, revealed signs of rejection in all allografts. In group A all except one animal and in group C the morphological changes were characterized by severe acute rejection. In contrast, one animal in group A and all the animals in group B revealed signs of moderate acute rejection and in most animals signs of chronic rejection were also found. The reduction of Pan-T and CD4+ cells in group B compared to the control group was associated with no clinical rejection, while the increase of CD8+ cells in group C and partly in group A (except for animal 3) was associated with clinical rejection. No difference in LP was detected between groups A and B in the study period. We concluded that a combination of CSA, LF and splenectomy was efficient in preventing clinical rejection, however, there were signs of rejection morphologically even in animals without clinical rejection. The changes in LP over time could not predict the clinical outcome. However, increase in CD8+ cells was highly associated to clinical rejection among nonimmunosuppresed animals.

Hamster to rat kidney transplantation: technique, functional outcome and complications

Hamster to rat kidney transplantation has only recently been introduced as model of concordant xenografting. The kidney model offers unique possibilities for studying both immunological and functional aspects of xenografts as opposed to the widely used heterotopic heart model. This article provides a detailed description of surgical technique as well as data on functional outcome and complications. The renal artery with a small segment of the aorta is sutured end-to-side to the abdominal aorta of the recipient, and the renal vein is anastomosed end-to-side to the inferior vena cava. The urinary system is reconstructed by bladder-to-bladder anastomosis. Xenografts will maintain close to normal serum-creatinine levels for 2-3 days, after which they are rejected. Complications occurred in 22% of xenografts. Postrenal obstruction due to severe hematuria or ureter stenosis was the most frequent problem encountered.

Xenotransplantation

Xenotransplantation means transplantation of organs and tissues from animals to human beings. Today, with use of new and more conventional immunosuppressive substances, it is possible to achieve good long-term survival of organs and cells transplanted between closely related species; for example, between baboon and man. However, large-scale treatment by xenotransplantation is still not possible because a transplantation between species such as pig and man will still not be successful. Nevertheless, many researchers have tried to solve these problems, and it is hoped that transgenic animals in combination with newer immunosuppressive treatment will make xenotransplantation a realistic possibility. The time horizon for clinically successful xenotransplantation with pig organs is unknown at the moment. Nevertheless, many investigators think that the breakthrough will occur in a few years time.