Set-up variation of patients treated with radiotherapy to the prostate measured with an electronic portal imaging device

The set-up variation of 11 patients treated supine with radical radiotherapy for carcinoma of the prostate was measured with an electronic portal imaging device to determine the adequacy of set-up techniques and current margins, as well as the need for immobilization. During the treatments 172 images of the anterior fields and 159 images of the left-lateral fields were taken and the errors in treatment placement were measured by template matching. The variation in the superior-inferior direction was small, 1.4-1.6 mm (1 SD), while the medio-lateral variation was 2.8 mm (1 SD). The anterior-posterior variation was largest, 4.6 mm (1 SD) with an offset of 3.3 mm anterior. This anterior offset and large anterior-posterior variation suggests that set-up techniques were not optimal for this direction. The 1 cm margin used was adequate for set-up variation except in a small number of cases, which was mainly due to the anterior trend. Random (treatment-to-treatment) variations were small (1.1-2.3 mm; 1 SD), indicating that immobilization would result in only modest improvement in reproducibility for these supine patients.     

Apoptosis induced in vitro and in vivo during infection by Ebola and Marburg viruses

Induction of apoptosis has been documented during infection with a number of different viruses. In this study, we used transmission electron microscopy (TEM) and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling to investigate the effects of Ebola and Marburg viruses on apoptosis of different cell populations during in vitro and in vivo infections. Tissues from 18 filovirus-infected nonhuman primates killed in extremis were evaluated. Apoptotic lymphocytes were seen in all tissues examined. Filoviral replication occurred in cells of the mononuclear phagocyte system and other well-documented cellular targets by TEM and immunohistochemistry, but there was no evidence of replication in lymphocytes. With the exception of intracytoplasmic viral inclusions, filovirus-infected cells were morphologically normal or necrotic, but did not exhibit ultrastructural changes characteristic of apoptosis. In lymph nodes, filoviral antigen was co-localized with apoptotic lymphocytes. Examination of cell populations in lymph nodes showed increased numbers of macrophages and concomitant depletion of CD8+ T cells and plasma cells in filovirus-infected animals. This depletion was particularly striking in animals infected with the Zaire subtype of Ebola virus. In addition, apoptosis was demonstrated in vitro in lymphocytes of filovirus-infected human peripheral blood mononuclear cells by TEM. These findings suggest that lymphopenia and lymphoid depletion associated with filoviral infections result from lymphocyte apoptosis induced by a number of factors that may include release of various chemical mediators from filovirus-infected or activated cells, damage to the fibroblastic reticular cell conduit system, and possibly stimulation by a viral protein.     

Endemic Lassa fever in Liberia. I. Clinical and epidemiological aspects at Curran Lutheran Hospital, Zorzor, Liberia

In a study to assess the epidemiological and clinical aspects of endemic Lassa fever (LF) in Liberia at Curran Lutheran Hospital (CLH), 44 cases were diagnosed by virological and serological techniques over a 22-month period. During one calendar month, testing of febrile patients admitted to the medical-surgical ward revealed six cases of LF, 13% of all febrile cases and 17% of those who were tested. As the study progressed the diagnostic skills of the hospital staff improved. The most common mistake was the diagnosis of a case of LF as pneumonia; the most potentially serious diagnostic problem was differentiating LF from typhoid fever, a readily treatable infection. LF may also mimic other diseases such as aseptic meningitis, pelvic inflammatory disease, gastroenteritis or arbovirus infection. We found a previously unreported symptom of LF, rib tenderness typical of costochondritis. The mortality rate in the medical-surgical ward was 5.4%; the over-all case-fatality rate was 13.6%. Women outnumbered men by nearly three to one, and had a higher mortality particularly noted in the pregnant. LF is common at CLH, and as many as 100 cases may occur annually at this hospital.     

Endemic Lassa fever in Liberia. II. Serological and virological findings in hospital patients

Patients admitted with fever to four Liberian hospitals were tested for Lassa fever (LF) by means of the indirect fluorescent antibody technique and by virus isolation. The incidence of LF and presumptive LF among consecutive febrile adult patients was 14% and 17% in two hospitals located in the interior; no cases of LF were found among 24 consecutive patients in a hospital near the coast. In the three inland hospitals the incidence of confirmed or presumptive LF among the patients in whom the diagnosis was seriously considered varied from 13% to 36%. Lassa virus was isolated from 17 patients out of the 59 cases found in this survey.LF is a common cause of fever in northern Liberia. The diagnosis depends upon the readiness of the staff to consider the diagnosis, the collection of blood specimens at appropriate times, and the preservation of sera at sub-freezing temperatures to permit survival of active virus and its subsequent recovery in an appropriate laboratory.     

Radioimmunoassay of factor V in human plasma and platelets

Homogeneous, single-chain human factor V was used to develop a double antibody competition radioimmunoassay to measure factor V concentrations in plasma and platelets. Standard curves were constructed that allow for the detection of as little as 20 ng factor V/ml of plasma. Normal factor V concentrations range from 4 to 14 micrograms/ml of plasma with an average value of 7.0 +/- 2.0 micrograms/ml (n = 64). No correlation was observed between antigen levels and age or sex. The radioimmunoassay data are consistent with factor V clotting assays, providing freshly drawn plasma is used in the bioassay. Radioimmunoassay of washed platelets indicate that 0.63-1.93 microgram of factor V is present per 2.5 X 10(8) platelets (4612-14128 molecules of the factor V platelet). When normalized to individual hematocrits and platelet count, the data indicated that platelets contribute approximately 18%-25% of the factor V found in whole blood. In addition, two individuals with functionally deficient factor V were examined and found to be deficient in both antigen and activity.     

Homogeneity of Venezuelan Encephalitis Virion Populations of Hamster-Virulent and Benign Strains, Including the Attenuated TC83 Vaccine

A hamster-virulent strain of Venezuelan encephalitis virus (BeAn8, subtype III) and a benign strain (BeAr35645, subtype IV) each yielded 100 clones with virulence properties like those of the parental virion population. Another hamster-virulent strain (63U2, subtype I, variety E) was heterogeneous since 2 out of 100 clones were less virulent for hamsters than the other 98 clones or the parental virus population. The attenuated TC83 vaccine strain, (a derivative of subtype I, variety A), although over 99% homogeneous with respect to hamster virulence, was unstable since virulent virions could be selected from the parental population by passage through hamsters.