SU-E-T-231: Comparison of Beam Characteristics of Small Field 6 MeV Electrons as Replacement for Superficial X Ray Beam.

PURPOSE: To compare beam characteristics of superficial X-rays with 6 MeV Electrons for the purpose of replacing superficial treatments with electron fields for skin lesions. METHODS: Electron beam cutouts were made with 12mm thickness cerrobend in diameters 2-5 cm to match superficial X-ray machine cones. Central axis depth doses and profiles were generated using 0.007 cc Exradin A-16 ion chamber, in PTW water phantom at 1mm steps, at 96 and 100cm SSD for electron beams, and at 15cm SSD for superficial X-rays. From the beam data, radiation penumbra 90-10%, 90% profile width, peripheral dose and percentage depth dose were obtained for comparison. RESULTS: The 90-10% radiation penumbra was ranging 7.4-13.7 mm, 12.6-17.6 mm for 6 MeV electrons at 96 and 100cm SSD respectively, and 4.2-11.4 mm for 2-5 cm superficial X-ray cones. For 90% treatment width, a margin ranging 5-7 mm, 6-9 mm is needed around the periphery of target for 6 MeV Electrons at 96 and 100cm SSD respectively, and 2-3 mm for superficial X-ray cones. For 96cm SSD, the peripheral dose from the geometrical field edge were 3.9% at 1cm and 0.5% at 2cm. It was 2.6% at 1cm and 0.7% at 2cm for 100cm SSD. For superficial, it was 6.2%, 7.5%, 9.1% at 1cm, and 3.4%, 4.3%, 5.6% at 2cm for 100 kV, 120 kV and 150 kV respectively. The electron surface dose was below 90%. CONCLUSION: 6 MeV Electron beam shows high superiority with rapid fall off of dose beyond target with lower peripheral dose compared to superficial X-rays. However, the electrons need higher margin around the target and also need appropriate bolus thickness to increase skin dose. The dose at depth beyond 2cm makes very significant advantage using electrons compared to superficial X-rays.

Genotoxicity surveillance programme in workers dismantling World War I chemical ammunition.

PURPOSE: To evaluate the effectiveness of personal protective measures in a dismantling plant for chemical weapons from World War I of the Belgian Defence. METHODS: Seventeen NIOSH level B-equipped plant workers exposed to arsenic trichloride (AsCl(3)) in combination with phosgene or hydrogen cyanide (HCN) were compared to 24 NIOSH level C-protected field workers occasionally exposed to genotoxic chemicals (including AsCl(3)-phosgene/HCN) when collecting chemical ammunition, and 19 matched referents. Chromosomal aberrations (CA), micronuclei (MNCB and MNMC), sister chromatid exchanges (SCE) and high frequency cells (HFC) were analysed in peripheral blood lymphocytes. Urinary arsenic levels and genetic polymorphisms in major DNA repair enzymes (hOGG1(326), XRCC1(399), XRCC3(241)) were also assessed. RESULTS: SCE and HFC levels were significantly higher in plant-exposed versus referent subjects, but MNCB and MNMC were not different. MNCB, SCE and HFC levels were significantly higher and MNMC levels significantly lower in field-exposed workers versus referents. AsCl(3) exposure was not correlated with genotoxicity biomarkers. CONCLUSIONS: Protective measures for plant-exposed workers appear adequate, but protection for field-exposed individuals could be improved.

[Evaluation of 3D numerisation with structured light projection in breast surgery]. / Evaluation de l'imagerie tridimensionnelle acquise par une technique de projection de lumière structurée en chirurgie mammaire.

INTRODUCTION: Breast plastic surgery still remains subjective with no objective measurement tool to evaluate and to predict our results. In this aim, we did an evaluation of a new 3D surface measurement tool using the structured projected light technology (Inspeck) in breast surgery. MATERIAL AND METHOD: We evaluated the different measurement tools available (euclidean distance, projected on the surface distance, and volume measurement) with the numerisation system on distance and silicone prosthesis of known length and volume. These measurements were done experimentally and on patients. We also numerised more than 50 patients to evaluate the feasibility of this technology in current practice. RESULTS: We manage to highlight the advantages of this technology compared to other technology in terms of feasibility, restrictions, harmlessness and reproducibility. This tool is well adapted for a use in current practice. Only the volume measurement tool has to be improved. CONCLUSION: The perspectives of 3D numerisation with structured light projection are wide in clinical practice. It could bring a bit of objectivity in breast plastic surgery.

Potent induction of focused Th1-type cellular and humoral immune responses by RTS,S/SBAS2, a recombinant Plasmodium falciparum malaria vaccine.

The RTS,S/SBAS2 vaccine confers sterile protection against Plasmodium falciparum sporozoite challenge. The mechanisms underlying this are of great interest, yet little is known about the immune effector mechanisms induced by this vaccine. The immune responses induced by RTS,S/SBAS2 were characterized in 10 malaria-naive volunteers. Several epitopes in the circumsporozoite protein (CSP) were identified as targets of cultured interferon (IFN)-gamma-secreting CD4+ T cells. RTS,S-specific IFN-gamma-secreting effector T cells were induced in 8 subjects; this ex vivo response mapped to a single peptide in Th2R. CSP-specific CD8+ cytotoxic T lymphocytes were not detected. RTS, S-specific IFN-gamma production was universal, whereas interleukin-4 and -5 production was rare. RTS,S-specific lymphoproliferative responses and antibodies to CSP were strongly induced in all volunteers. Responses waned with time but were boostable. Thus, RTS, S/SBAS2 is a potent inducer of Th1-type cellular and humoral immunity. These results highlight possible immune mechanisms of protection and have important implications for vaccine design in general.

A phase I safety and immunogenicity trial with the candidate malaria vaccine RTS,S/SBAS2 in semi-immune adults in The Gambia.

RTS,S is a novel pre-erythrocytic malaria vaccine based on the circumsporozoite surface protein (CSP) of Plasmodium falciparum linked to hepatitis B surface antigen (HBs) and combined with a novel adjuvant system (SBAS2). We have conducted a Phase I trial with three doses of this vaccine given at 0, 1, and 6 months to 20 semi-immune, adult, male volunteers in The Gambia to assess its safety and immunogenicity. Eighteen of the 20 volunteers completed the study. There were no clinically significant local or systemic adverse events following each vaccination. Hematologic and biochemical indices before and two weeks after each vaccination showed no evidence of toxicity. Antibody titers to both CSP and HBs showed a significant increase after vaccination; these were the largest after the third dose. We conclude that the RTS,S/SBAS2 vaccine induces no significant toxicity in this semi-immune population and produces significant increases in antibody titers to CSP.

Calmodulin immunoelectron microscopy: redistribution during ram spermatogenesis and epididymal maturation. II.

Affinity-purified monospecific antibodies and indirect immunogold and immunoferritin labeling on ultra-thin sections of low-temperature Lowicryl K4M-embedded samples were used to study the redistribution of calmodulin in ram spermatids and epididymal spermatozoa at the electron microscopic level. Calmodulin appeared as an integral component of well-defined structures or organelles of these cells. In young spermatids, calmodulin was localized in the nucleus, cytoplasm, and developing acrosome. During spermatogenesis and epididymal maturation, calmodulin left the acrosome to reach the perinuclear substance and finally became concentrated in the post-acrosomal area of the head, although some calmodulin remained associated with the tip of the acrosome. Such a redistribution is consistent with the preferential location of Ca2+ in the post-acrosomal cytoplasm of ejaculated spermatozoa. Calmodulin was also observed in the flagellum associated with the plasma membrane and with the motility apparatus, between coarse fibers and axonemal microtubules. These changes in calmodulin distribution may account for the Ca2+-dependent regulation of spermatogenesis and sperm maturation. Calmodulin therefore appears to be a pleiotropic regulator of male gamete development and functions.

Immunoelectron microscopic localization of calmodulin and phospholipase A2 in spermatozoa. I.

Using the Lowicryl K4M embedding technique, together with indirect immunoferritin or immunogold labeling on ultra-thin sections, tubulin, calmodulin and phospholipase A2 were distinctly localized in ejaculated bull spermatozoa. Calmodulin was concentrated on the plasma membrane, nucleus, post-acrosomal substance, and, in lesser amounts, between coarse fibers and axonemal microtubules of the flagellum. Phospholipase A2 was distributed evenly along the plasma membrane, nucleus, acrosome, post-acrosomal substance, and in the flagellum, on mitochondria, fibrous sheath, coarse fibers, between coarse fibers and axonemal microtubules. Antibodies to tubulin labeled only axonemal microtubules, including the central pair of microtubules. Patterns of tubulin labeling were identical when ferritin granule- or gold particle-conjugated antibodies were tested. In agreement with our previous biochemical studies demonstrating calmodulin binding to phospholipase A2, concomitant with enhancement of phospholipase A2 activity (Arch Biochem Biophys 241:413, 1985), the overlapping distribution of calmodulin and phospholipase A2 in several parts of the sperm suggests that these proteins may play a concerted role in male gamete function in preparation for or during fertilization. The distinct distribution of tubulin along flagellum microtubules indicates their special function in sperm mobility.

Platelet cytoskeleton alpha-actinin in normal and thrombasthenic platelets: distribution and immunologic characterization.

The subcellular localization of alpha-actinin (Mr 100,000) in human skeletal muscle is restricted to the Z line, in which it is believed to anchor actin filaments. Recently, this protein was identified in normal and thrombasthenic human platelets by its antigenic cross-reaction with antibodies to chicken gizzard alpha-actinin. In our study, the biochemical interaction between purified platelet alpha-actinin and striated muscle F-actin was examined by electron microscopy of negatively stained preparations. Like its muscle counterpart, platelet alpha-actinin promotes the cross-linking and bundling of actin filaments. Antibodies prepared to human platelet alpha-actinin cross-reacted with chicken gizzard alpha-actinin as shown by immunoelectrophoresis and the western blotting technique. Immunoblots prepared with normal and thrombasthenic platelets with antibodies to human platelet alpha-actinin revealed that this protein is susceptible to proteolysis. Extracts of freshly drawn platelets showed a protein band of 100 K. When the platelet extracts were incubated at 37 degrees C for various times, the immunoblots showed protein bands of 100 and 80 K. The proportion of the 80 K protein band increased with incubation time. This proteolysis can be prevented by chelating agents such as EDTA or the protease inhibitor leupeptin. Indirect immunofluorescent studies of human skin fibroblasts with antibodies to chicken gizzard actin and human skeletal muscle, chicken gizzard, and platelet alpha-actinin revealed the staining pattern characteristic of each protein. The distribution of alpha-actinin in normal and thrombasthenic platelets was assessed by ferritin-labeled immunoelectron microscopy. Ferritin particles were found in the cytoplasm immediately below the membrane and in some granules. There was no labeling associated with the mitochondria.

Effect of phospholipid on factor VIII coagulant activity and coagulant antigen.

Incubation of purified factor VIII/von Willebrand factor complex or plasma with certain phospholipid preparation induced a two to threefold increase in apparent factor VIII activity, while a slight decrease of factor VIII coagulant antigen was observed. Between six or eightfold activity increases occurred when 10-3 units/ml of thrombin was present during the incubation. When the phospholipid was added first and the thrombin added 30 minutes later a twofold increase in apparent factor VIII activity occurred during the first part and this activity was then increased threefold further after the addition of thrombin. In separate experiments using gel filtration on Sepharose 2B, association of factor VIII activity to phospholipid vesicles could be demonstrated. This phospholipid bound factor VIII could be activated by thrombin. The relationship between these observations and the formation of factor X activating complex is discussed.

Studies on a monoclonal antibody to human factor viii coagulant activity, with a description of a facile two-site factor VIII coagulant antigen assay.

IgG was purified from the ascites tumor fluid obtained from mice injected with a monoclonal cell line secreting antibody that inhibited VIII:C. With a modified Bethesda assay method (18 hr, 4 degrees C), the titer of the purified IgG was 14,000 U/mg. In a fluid-phase IRMA for VIII:CAg utilizing the Fab fragment prepared from the monoclonal IgG, two high-titer human anti-VIII:C inhibitors (IgG fractions) showed no demonstrable competition for the monoclonal VIII:CAg binding site. Conversely, neither human antibody (125I-Fab fragment) was displaced from its VIII:CAg binding site by the monoclonal IgG molecule. When the monoclonal antibody was used in a fluid-phase IRMA, slightly decreased VIII:CAg levels were found in serum. A facile one-step, two-site IRMA using Sepharose-bound human anti-VIII:C and labeled monoclonal IgG was designed. With this assay, in contrast to the finding with the fluid-phase IRMA, both the rate and apparent level of binding of VIII:CAg "sandwiched" between the two antibodies were increased approximately twofold in serum compared to the native plasma. A similar increase in rate and apparent level of binding was also found after thrombin treatment of VIII:C/vWf relative to the untreated control preparation.

The effect of naturally occurring antibodies to factor VIII on an immunoradiometric assay for factor VIII coagulant antigen. Observation on a cross-reacting material-positive (CRM+) hemophiliac with a factor VIII inhibit.

An IRMA for VIII:CAg was performed on plasma samples from 13 hemophilic and four nonhemophilic subjects, containing naturally occurring antibodies against factor VIII. The VIII:C binding ligand was an iodinated Fab fraction of a high-titer factor VIII antibody arising in a hemophiliac. Since the IRMA is an equilibrium binding assay, the inclusion of an antibody against VIII:C in the test system would be expected to compete with the ligand for the available antigenic sites on the VII:C molecule: the higher the titer of the antibody expressed in BIU, the greater the degree of inhibition of the IRMA measuring VIII:CAg. In a mixture of equal parts of normal and inhibitor plasmas, the amount of residual VIII:C remaining after 2 hr incubation at 37 degrees C differed from the residual VIII:CAg in half (three of six) of the high-titer inhibitors (> 30 BIU) so studied. In the inhibitors of lower titer (< 20 BIU), correlation between BIU and the percentage of VIII:CAg neutralized was not observed. Three of these inhibitor plasmas did not significantly compete with the ligand. With this competitive protein-binding technique the four plasmas with spontaneous inhibitors could not be distinguished from those arising in hemophiliacs. In one hemophilic plasma the titer of VIII:C inhibitor over a 6-day span increased from 4 to 500 BIU as the VIII:CAg level dropped from 84% to 2%. The finding of circulating VIII:CAg in the presence of an VIII:C inhibitor further substantiates the heterogeneity of the naturally occurring VIII:C antibody and is evidence that factor VIII inhibitors can occur in CRM+ hemophilia.

Subarachnoid hemorrhage secondary to ruptured aneurysms in infants. Report of two cases.

Two infants with subarachnoid bleeding from middle cerebral artery aneurysms are presented, with detailed case histories.

The action of immobilized thrombin on factor VIII, fibrinogen and a synthetic tripeptide.

Bovine thrombin was insolubilized by attachment to cyanogen bromide-activated Sepharose (Sepharose-thrombin) or to activated (Affi-Gel 10) agarose containing a 10 A long arm (Affi-Gel-thrombin). Coupling in both instances approximated 7,000 units of thrombin per ml packed gel as determined by 125I-thrombin incorporation. The thrombin beads hydrolyzed the synthetic tripeptide Bz-Phe-Val-Arg-pNA (S-2160) at different rates, with the Sepharose-thrombin more active (220 esterase units per ml) than Affi-Gel thrombin (20.4 units per ml). The Km was significantly higher for the insolubilized thrombins (2 X 10(-3) M) than uncoupled thrombin (Km = 8 X 10(-5) M). The Sepharose-thrombin activated factor VIII significantly more rapidly than Affi-Gel-thrombin. Neither matrix-bound thrombin clotted a fibrinogen solution or liberated significant amounts of fibrinopeptides over 48 hr. This data indicates that a proteolysis of factor VIII, rather than a complex with thrombin, is the method of activation of factor VIII and that factor VIII is more accessible to the action of immobilized thrombin than is fibrinogen.

Spectrum of complications in the use of intrathecal fluorescein.

The authors describe a case in which 0.5 cc of 5% fluorescein diluted in 10 cc of cerebrospinal fluid (CSF) was injected at the L4-5 level for evaluation of nasal CSF leakage. Within minutes, tone increased in lower extremities accompanied by knee and ankle clonus and subjective numbness up to the waist. Non-preserved saline irrigation of the lumbar CSF was administered until it became clear, and the patient's head was elevated to retard the developing symptomatology. Although a transient temperature elevation was observed with negative CSF cultures, all signs and symptoms cleared within 48 hours. In a survey of the members of the Americal Association of Neurological Surgeons regarding frequency of use and complications stemming from intrathecal fluorescein, the response rate was 58.3% (1111) of the 1907 members, of which 6.8% (76) had used intrathecal fluorescein, and among those, 25% (19 of the 76) had observed complications involving lower extremity weakness, numbness, generalized seizure activity, opisthotonos, and cranial nerve deficit. No complications were permanent. The authors recommend caution if intrathecal fluorescein must be used. Means should be available to clear the CSF of the agent and elevate the head if complications arise.

Cerebral malakoplakia.

A newborn male developed diffuse myoclonus. Right frontal craniotomy revealed a thin hemispheric mantle and a cyst communicating with the right lateral ventricle. In the biopsy of the cyst wall there were the characteristic findings of malakoplakia, granulomatous inflammation with von Hansemann histiocytes and Michaelis-Gutmann bodies. The child died at 1 1/2 years of age.

Transorbital removal of intracranial foreign body in middle fossa.

A limited access to the middle cranial fossa can be achieved by an opening created in the posterior portion of the lateral orbital wall. An intracranial foreign body was removed by this method.