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PubMed2001

Scab diameters on pig skin resulting from hot particle exposures under varying conditions.

The National Council on Radiation Protection and Measurements (NCRP) in NCRP Report Number 106 recommended a limit of 10(10) beta particles emitted from radioactive particles with sizes less than 1 mm (hot particles) to prevent acute deep ulceration. This recommendation was determined, in part, by regressing the diameter of the scabs induced by fissioned 235UC2 hot particles as a function of the logarithm of the number of beta particles emitted from the sources for one study. To validate this recommendation and the approach used by the NCRP, external irradiations of pig skin using radioactive sources of less than 600 microm in the largest dimension were carried out. The hot particles used included fissioned 235UC2 and activated 170Tm, 175Yb, and 46Sc. Results indicated a strong correlation between scab diameter and dose for scabs induced using fissioned 235UC2, activated 170Tm, and 46Sc, but not for 175Yb. The correlation value decreased with decreasing beta particle energy, with the exception of 46Sc, which had scabs with diameters greater than twice the maximum beta particle range. The larger scabs from 46Sc are thought to be due to dose contributions from the gamma rays. The results also give an ulceration threshold less than that given by NCRP to prevent acute deep ulceration. It was concluded that regression analysis of scab diameter as a function of either number of beta particles emitted from the hot particles or dose did not yield either precise or accurate thresholds but was useful in determining probable ranges of doses which lead to scab induction.

Animals↗
PubMed1979

The ability of ionizing radiations of different LET to induce chromosomal deletions in Aspergillus nidulans.

Conidia, derived from a strain of Aspergillus nidulans known to carry a specific chromosomal duplication, were irradiated. The duplicated segment had genetic markers, which, when eliminated from the genome, allowed the easy detection of deletion mutants. Survival curves derived following 15 MeV electron and gamma-ray irradiation were characterised by the presence of an appreciable shoulder, whilst 50 kvp X-rays gave a much smaller shoulder. Irradiation with beta-particles and alpha-particles gave rise to exponential survival curves. The RBE values for these radiations, based on the D37 value were for gamma-rays, 1.0, 15 MeV electrons 1.0, 50 kvp X-rays 1.9, beta-particles 2.1 and alpha-particles 3.4. With the exception of gamma-rays the radiations described were compared with respect to their ability to induce chromosomal deletions. When the number of deletants amongst survivors was plotted against dose, a linear relationship was found for electrons, X-rays and beta-particles. The response recorded for alpha-particles was essentially linear but with a biphasic component. The RBE values for the radiations, based on a value of unity for 15 MeV electrons were as follows: X-rays 1.3, beta-particles 0.8, alpha-particles above 7.5 krad 2.3 and below 7.5 krad 3.5. When these same data were re-plotted with number of deletants amongst survivors against log survival, electrons appeared the most efficient radiation at producing deletants amongst survivors, with an "m value" of 283 X 10(-5). Tritiated water was least efficient, the corresponding value being 182 X 10(-5). The number of deletants per 10(4) conidia plated, when plotted against dose yielded a curve which increased to a peak and then decreased linearly for all radiations. The peaks for electrons, X-rays and alpha-particles each had a value of about 14 deletants per 10(4) conidia plated and the peaks roughly corresponded with the point at which the survival curve became exponential and was clearly indicative of the accumulation of sub-lethal damage. However, for beta-particles the peak had a value of 7 deletants per 10(4) conidia plated. A non-DNA target has been implicated for cellular death following beta-particle irradiation.

Americium↗
PubMed2002

Dose characterization in the near-source region for two high dose rate brachytherapy sources.

High dose rate (HDR) 192Ir sources are currently used in intravascular brachytherapy (IVB) for the peripheral arterial system. This poses a demand on evaluating accurate dose parameters in the near-source region for such sources. The purpose of this work is to calculate the dose parameters for the old VariSource HDR 192Ir source and the new microSelectron HDR 192Ir source, using Monte Carlo electron and photon transport simulation. The two-dimensional (2D) dose rate distributions and the air kerma strengths for the two HDR sources were calculated by EGSnrc and EGS4 Monte Carlo codes. Based on these data, the dose parameters proposed in the AAPM TG-60 protocol were derived. The dose rate constants obtained are 13.119+/-0.028 cGy h(-1) U(-1) for the old VariSource source, and 22.751+/-0.031 cGy h(-1) U(-1) for the new microSelectron source at the reference point (r0 = 2 mm, theta = pi/2). The 2D dose rate distributions, the radial dose functions, and the anisotropy functions presented for the two sources cover radial distances ranging from 0.5 to 10 mm. In the near-source region on the transverse plane, the dose effects of the charged particle nonequilibrium and the beta-particle dose contribution were studied. It is found that at radial distances ranging from 0.5 to 2 mm, these effects increase the calculated dose rates by up to 29% for the old VariSource source, and by up to 12% for the new microSelectron source, which, in turn, change values of the radial dose function and the anisotropy function. The present dose parameters, which account for the charged particle nonequilibrium and the beta particle contribution, may be used for accurate IVB dose calculation.

Brachytherapy↗
PubMed2000

Marrow toxicity of 33P-versus 32P-orthophosphate: implications for therapy of bone pain and bone metastases.

UNLABELLED: Several bone-seeking radiopharmaceuticals, such as 32P-orthophosphate, 89Sr-chloride, 186Re-1,1 hydroxyethylidene diphosphonate (HEDP), and 153Sm-ethylene diamine tetramethylene phosphonic acid (EDTMP), have been used to treat bone pain. The major limiting factor with this modality is bone marrow toxicity, which arises from the penetrating nature of the high-energy beta particles emitted by the radionuclides. It has been hypothesized that marrow toxicity can be reduced while maintaining therapeutic efficacy by using radionuclides that emit short-range beta particles or conversion electrons. In view of the significant clinical experience with 32P-orthophosphate, and the similarity in pain relief afforded by 32P-orthophosphate and 89Sr-chloride, this hypothesis is examined in this study using 32P- and 33P-orthophosphate in a mouse femur model. METHODS: Survival of granulocyte macrophage colony-forming cells (GM-CFCs) in femoral marrow was used as a biologic dosimeter for bone marrow. 32P- and 33P-orthophosphate were administered intravenously, and GM-CFC survival was determined as a function of time after injection and, at the nadir, as a function of injected activity. The kinetics of radioactivity in the marrow, muscle, and femoral bone were also determined. The biologic dosimeter was calibrated by assessing GM-CFC survival at its nadir after chronic irradiation of Swiss Webster mice with exponentially decreasing dose rates of gamma rays (relative biologic effectiveness equivalent to that of beta particles) from a low-dose rate 137Cs irradiator. Dose-rate decrease half-times (Td) (time required for 137Cs gamma ray dose rate to decrease by one half) of 62, 255, and 425 h and infinity were used to simulate the dose rate patterns delivered by the radiopharmaceuticals as dictated by their effective clearance half-times from the mouse femurs. These data were used to experimentally determine the mean absorbed dose to the femoral marrow per unit injected activity. Finally, a theoretical dosimetry model of the mouse femur was developed, and the absorbed doses to the femoral marrow, bone, and endosteum were calculated using the EGS4 Monte Carlo code. RESULTS: When the animals were irradiated with exponentially decreasing dose rates of 137Cs gamma rays, initial dose rates required to achieve 37% survival were 1.9, 0.98, 0.88, and 0.79 cGy/h for dose rate decrease half-times of 62, 255, and 425 h and infinity, respectively. The D37 values were 144 +/- 15, 132 +/- 12, 129 +/- 3, and 133 +/- 10 cGy, respectively, compared with a value of 103 cGy for acute irradiation. When 32P and 33P were administered, the injected activities required to achieve 37% survival were 313 and 2,820 kBq, respectively. Theoretical dosimetry calculations show that 33P offers a 3- to 6-fold therapeutic advantage over 32P, depending on the source and target regions assumed. CONCLUSION: The low-energy beta-particle emitter 33P appears to offer a substantial dosimetric advantage over energetic beta-particle emitters (e.g., 32p, 89Sr, 186Re) for irradiating bone and minimizing marrow toxicity. This suggests that low-energy beta or conversion electron emitters may offer a substantial advantage for alleviation of bone pain as well as for specifically irradiating metastatic disease in bone.

Animals↗
PubMed1986

Applied principles of radiopharmaceutical use in therapy.

The initial consideration in use of a radiopharmaceutical in therapy is specificity of localization. A variety of biological principles such as active transport and binding to cellular components have been utilized to achieve this localization. The next concern is to maximize radiation to the lesion while minimizing that to the remainder of the body. This means that there is a major role to be played by emissions with a short path length (such as alpha particles, weak beta particles and Auger electrons). To achieve maximal irradiation of the lesion, dissociation of the radiolabel from the tissue should be minimized; potential approaches for achieving this are reviewed. Finally, "synergistic effects" between radiation and chemical agents are discussed.

Antibodies, Monoclonal↗
PubMed1991

Synergism between electricity and ionizing radiation.

Weak direct electric currents which produce little (or no) lethal damage to Escherichia coli bacteria are shown to act synergistically with ionizing radiation, both electromagnetic radiation (X-ray) and charged particles (beta radiation). This synergism greatly enhances the lethal effect of ionizing radiation on bacteria. This is possibly due to increased single-strand breaks in DNA, as detected by the alkaline sucrose gradient method. It is also shown that in cells with thymidine-3H incorporated into their DNA and treated with electricity, the radioactivity is released from the acid-insoluble fraction to the acid-soluble fraction, so that the ratio of radioactivity in the soluble fraction to that in the insoluble fraction increases from 0.47 in the non-treated control cells to 3.46 in the cells treated with an electric current of 1.0 mA (3.0 V) for 30 min, which indicates extensive degradation of cellular DNA. No synergism is detected between electricity and 254 nm UV radiation nor between electricity and X-rays, when these two agents are used sequentially in any order. Electricity alone produces lesions in cell membranes, as shown by electron microscopy.

Beta Particles↗
PubMed1997

Autoradiographic characterization of [3H]-5-HT-moduline binding sites in rodent brain and their relationship to 5-HT1B receptors.

5-HT-moduline is an endogenous tetrapeptide [Leu-Ser-Ala-Leu (LSAL)] that was first isolated from bovine brain tissue. To understand the physiological role of this tetrapeptide, we studied the localization of 5-HT-moduline binding sites in rat and mouse brains. Quantitative data obtained with a gaseous detector of beta-particles (beta-imager) indicated that [3H]-5-HT-moduline bound specifically to rat brain sections with high affinity (Kd = 0.77 nM and Bmax = 0. 26 dpm/mm2). Using film autoradiography in parallel, we found that 5-HT-moduline binding sites were expressed in a variety of rat and mouse brain structures. In 5-HT1B receptor knock-out mice, the specific binding of [3H]-5-HT-moduline was not different from background labeling, indicating that 5-HT-moduline targets are exclusively located on the 5-HT1B receptors. Although the distribution of 5-HT-moduline binding sites was similar to that of 5-HT1B receptors, they did not overlap totally. Differences in distribution patterns were found in regions containing either high levels of 5-HT1B receptors such as globus pallidus and subiculum that were poorly labeled or in other regions such as dentate gyrus of hippocampus and cortex where the relative density of 5-HT-moduline binding sites was higher than that of 5-HT1B receptors. In conclusion, our data, based on autoradiographic localization, indicate that 5-HT-moduline targets are located on 5-HT1B receptors present both on 5-HT afferents and postsynaptic neurons. By interacting specifically with 5-HT1B receptors, this tetrapeptide may play a pivotal role in pathological states such as stress that involves the dysfunction of 5-HT neurotransmission.

Animals↗
PubMed2002

Microdistribution of alpha particles in pathological sections of tissues from thorotrast patients detected by imaging plate autoradiography.

Thorotrast is a colloidal suspension of radioactive (232)ThO(2) that naturally emits alpha particles (90%), beta particles and gamma rays (10%). Thorotrast was used as a radiographic contrast agent in the 1930s-1950s; it caused liver cancer several decades after injection because of its life-long deposition and exposure. Determination of the amount and the distribution of radioactive thorium are essential for assessment of radiation risks. We visualized alpha particles on ordinary archival tissue sections using an imaging plate and a BAS5000 image analyzer. Furthermore, we confirmed that the imaging system is sensitive enough to detect alpha particles and accurate in measuring the total amount of thorium deposited in the organ from a single tissue section. This method revealed that the amount of thorium deposited in tumor tissue is correlated to that in non-tumor tissue. Thorotrast deposition was not associated with DNA damage determined by histochemistry. In combination with histological findings, it is suggested that radioactive thorium always migrates within the deposited organs by macrophages, and that the organs are evenly exposed to alpha particles.

Aged↗
PubMed2002

Production, PET performance and dosimetric considerations of 134Ce/134La, an Auger electron and positron-emitting generator for radionuclide therapy.

We propose the use of the Auger electron and positron-emitting generator 134Ce/134La (half-lives 3.16 d and 6.45 min) for radionuclide therapy. It combines emission of high-energy beta particles with Auger electrons. The high-energy beta particles have similar energies as those emitted by 90Y. Many cancer patients receiving radionuclide therapy have both bulk tumours, which are best treated with high-energy beta particles, and single spread cells or micrometastasis, which are preferably treated with low-energy electrons such as Auger and conversion electrons. Furthermore, the positron-emitting 134La can be used to study kinetics and dosimetry using PET. Production and PET performance were investigated and theoretical dosimetry calculations were made. PET resolution, recovery and quantitative accuracy were slightly degraded for 134La compared to 18F. 134Ce/134La absorbed doses to single cells were higher than absorbed doses from 90Y and 111In. Absorbed doses to spheres representing bulk tumours were almost as high as for 90Y, and a factor 10 higher than for 111In. Whole-body absorbed doses, based on kinetics of the somatostatin analogue octreotide, were higher for 134Ce/134La than for 90Y because of the 134La annihilation photons. This initial study of the therapeutic possibilities of 134Ce/134La is encouraging and justifies further investigations.

Cesium Radioisotopes↗
PubMedDate not supplied

Radiochemical analysis of 93Zr.

The zirconium isotope 93Zr is a long-lived pure beta-particle-emitting radionuclide, which is produced by nuclear fission and neutron activation of the stable isotope 92Zr. This element is a constituent of the structural components of nuclear reactor vessels. A selective liquid-liquid extraction method for radiochemical separation of Zr, based on liquid-liquid extraction with 1-(2'-thenoyl)-3,3,3-trifluoroacetone in xylene and a subsequent stripping of 93Zr by an aqueous acid solution, has been developed. The method was utilised to separate Zr from other pure beta-particle and beta-gamma emitters in different kinds of samples. Decontamination factors higher than 99% for the pure beta-particle and beta-gamma emitters and an overall chemical yield of 80% were obtained. The sensitivity of the method allows the determination of the isolated 93Zr by liquid scintillation counting and the minimum detectable activity value obtained was 0.067 Bq over a counting period of 60 min.

Journal Article↗
PubMed2004

Electro-optic characteristics of optically interacting beta-FeOOH particles.

In this article the influence of multiple light scattering on the basic electro-optic parameters of optically dense colloidal particles is analyzed. The model system is an aqueous suspension of monodisperse ellipsoidal beta-FeOOH particles that displays large electric light scattering variations, including sign reversal, at very low particle volume fractions (two orders of magnitude below the critical concentration of particle electric interactions). The scaling method permits the relative variations in particle electric polarizability to be followed and its relaxation frequency to be determined. Particle rotational relaxation frequency and the phase shift of the responses at this frequency are obtained by the alternating component of the effects. Characteristic field intensity curves in the low-frequency range are used to follow the relative changes induced by the slow electrokinetic effect. The experimental results show that, despite the drastic variations in the effects with volume fraction, the basic electro-optic parameters are independent of multiple scattering and can be adequately determined for any particle concentration, excluding a narrow range in the vicinity of the electro-optic sign reversal. The investigation demonstrates that the dependence of the frequency behavior of aqueous beta-FeOOH on particle volume fraction reported in the literature is due not to optical interactions but to variation of particle surface electric state in the process of dilution.

Journal Article↗
PubMed1993

Vertebral malformations in medaka (teleost fish) after exposure to tritiated water in the embryonic stage.

This study was designed to investigate radiation-induced vertebral malformations in medaka embryos irradiated with beta particles from tritium. Embryos of two inbred strains (HO4 and HO5) of medaka, Oryzias latipes, were exposed either to different concentrations of tritiated water (9.25-37 MBq/ml) or to 137Cs gamma rays (dose rates of 0.44-1.89 Gy/day) continuously from morula to hatching. The newly hatched fry were removed from the radiation field and kept under usual conditions for 1 month. Young fish were fixed in 10% buffered formalin, cleared in 1% KOH, stained with alizarin red S, and kept in glycerine. There was almost no difference in the response to radiation between medaka strains. No marked reduction of hatching rate was observed after chronic irradiation with beta particles and gamma rays, but a considerable reduction in survival of fry was detected in irradiated groups within 1 month after hatching. From observation of whole-mounted skeleton specimens, the following vertebral malformations were found in irradiated groups: fusion of two or more vertebrae, incomplete formation of vertebrae, and lack of vertebral process. The incidence of vertebral malformations increased significantly in both groups irradiated with tritium beta particles and 137Cs gamma rays. A similarity in the incidences was also observed between beta-particle- and gamma-irradiated groups. The RBE of beta particles relative to gamma rays was estimated to be 1 based on the dose-response relationships observed.

Abnormalities, Radiation-Induced↗
PubMed1997

Enhanced neoplastic transformation in an inhomogeneous radiation field: an effect of the presence of heavily damaged cells.

In the inhomogeneous radiation field surrounding small beta-particle sources, nonlethally and heavily damaged cells are in proximity, permitting interaction via extracellular signals. This situation is typical of hot particles such as those released during the accident at Chernobyl. Beta-particle-emitting yttrium-90 wires (average energy 934 keV) were employed to investigate radiation-induced neoplastic transformation under these conditions. Integrated 24-h doses ranging from 0 to 750 Gy across the exposure field were applied. At equal levels of toxicity a 10-fold enhancement of neoplastic transformation frequency in C3H 10T1/2 cells was observed in the presence of heavily damaged cells. Homogeneous fields of low-dose-rate beta-particle radiation produced neoplastic transformation frequencies typical for comparable photon exposures reported in the literature.

Animals↗
PubMed1996

Experimental results with endovascular irradiation via a radioactive stent.

PURPOSE: The objective of this article is to describe the methods used to manufacture a radioactive stent and to review the experimental data on this therapy designed to improve arterial patency rates after stent placement. MATERIALS AND METHODS: Surface activation in a cyclotron and ion implantation techniques are used to render commercially available vascular stents radioactive. beta-Particle-emitting stents, most commonly 32P, were employed because of their short half-life (14.3 days) and limited range of tissue penetration (3-4 mm). The function and vascular response to these 32P radioactive stents with varying activities (range 0.14-23 microCi) was evaluated in several animal models of arterial injury and restenosis. RESULTS: In porcine iliac arteries, beta-particle-emitting stents with an initial activity of 0.14 microCi reduced neointimal formation 37% at 28 days after implant. On histology, the neointima consisted of smooth muscle cells and a proteoglycan-rich matrix. Scanning electron microscopy demonstrated complete endothelialization of the stent. beta-Particle-emitting stents with an initial activity of 3-23 microCi inhibited neointimal smooth muscle cell proliferation at 28 days in a porcine coronary restenosis model. The neointima within these high-activity stents consisted of fibrin, erythrocytes, and only rare smooth muscle cells. Studies with 1-year follow-up after implantation of a radioactive stent with a composition of gamma- and beta-particle-emitting radionuclides 55,56,57Co, 52Mg, and 55Fe and an initial activity of 17.5 microCi demonstrated almost complete inhibition of neointimal proliferation in a rabbit model. CONCLUSION: Endovascular irradiation delivered via a radioactive stent reduces neointimal formation and improves luminal patency without increasing the risk for stent thrombosis in experimental models of restenosis. The optimal radiation dose is unknown. At stent activities >3 microCi of 32P, the inhibition of neointimal formation is due to direct radiation affects on proliferating smooth muscle cells. At ultra-low activities (0.14 microCi), beta-particle irradiation reduces neointimal formation possibly by impairing cell proliferation or migration. This novel therapy may have a significant impact on preventing stent restenosis, and requires further investigation.

Animals↗
PubMed2001

Receptor-mediated phagocytosis of rat macrophages is regulated differentially for opsonized particles and non-opsonized particles containing beta-glucan.

Experiments were conducted to test the hypothesis that opsonic and non-opsonic phagocytic capacities are differentially regulated by resting and wound-derived macrophages. Furthermore, the phagocytosis of non-opsonized zymosan and beta-glucan particles was quantified to determine whether cells differentially regulate non-opsonic lectinophagocytosis in accordance with the carbohydrate composition of the ligand. In that regard, wound macrophages exhibited profound differential regulation in lectinophagocytosis with a seven-fold increase in phagocytosis of beta-glucan particles following overnight culture but with a relatively modest increase in internalization of mannan-containing zymosan. Cultured peritoneal macrophages increased uptake of both particles similarly. Upon activation with interferon-gamma/lipopolysaccharide (IFN-gamma/LPS), wound macrophages selectively suppressed beta-glucan ingestion, while phagocytosis of zymosan particles was unaffected. Lectinophagocytosis was decreased in activated peritoneal macrophages regardless of particle composition and was due in part to a nitric oxide-dependent mechanism which was without a role in regulation of wound macrophage lectinophagocytosis. Overnight culture of wound macrophages suppressed their capacity for opsonic-dependent phagocytosis independently of activation, whereas suppression of phagocytosis by peritoneal macrophages was activation-dependent. Regulation of all three phagocytic pathways was achieved distinctly by peritoneal and wound-derived macrophages, with changes found in the percentage of resident peritoneal macrophages capable of phagocytosis, whereas the phagocytic capacity of wound macrophages was primarily affected by the number of particles ingested by individual cells. Taken together, these findings demonstrate that the differential regulation of phagocytic pathways encompasses the nature of the phagocytic particle, the site from which macrophages are obtained, their response to activating agents and the mechanism through which the cell population alters its phagocytic potential.

Animals↗
PubMed1999

Finger doses received during 153Sm injections.

This study was undertaken to determine the dose received by the skin of the fingers of clinical and laboratory staff during injections of 153Sm. The use of 153Sm, chelated with ethylenediaminetetramethylene phosphonic acid (153Sm-EDTMP), is coming into more frequent use in radionuclide therapy since its approval by the U.S. Food and Drug Administration in March 1997. 153Sm emits a range of medium-energy therapeutically useful beta particles that have been found beneficial in the palliation of metastatic bone cancer pain. It also emits a range of gamma rays. Calculations have been undertaken to provide the beta-particle and gamma-ray dose rates, at a depth within the skin corresponding roughly to the basal cell layer, when the finger is placed in direct contact with the external surface of a syringe containing 153Sm. The beta-particle dose rates were modeled using an empirically based Monte Carlo approach previously described by Beddoe and Kelly. The gamma-ray dose rates were modeled using a distributed point source approach previously reported by Pattison et al. In the calculations it is assumed that a typical administered activity is 2.6 GBq, with a finger-syringe contact time of 30 s. The skin dose, due to both beta particles and gamma rays when the finger is centrally placed over an active volume of 0.3 mL in a 1-mL syringe, is calculated to be 77 mGy per injection. Similarly, for an active volume of 1.0 mL in a 2.5-mL syringe, the dose is calculated to be 10 mGy per injection. In view of the ICRP recommended weekly skin dose limit of 10 mGy, both of the above two doses are excessive. If, however, the fingers are placed at the rear end of the syringe barrel, where they are only exposed to the gamma rays, the above two doses are reduced to 0.069 and 0.139 mGy per injection, respectively. Both of these two doses are well within the recommended weekly dose limits for the skin. It is found that the weekly dose limit for the skin is readily exceeded if the fingers are in direct contact with the external surface of the syringe and located over the active volume. However, if handled at the rear end of the syringe barrel, a typical weekly workload can be managed without exceeding the recommended dose limits.

Beta Particles↗
PubMed1993

Recombinant RNA phage Q beta capsid particles synthesized and self-assembled in Escherichia coli.

The Escherichia coli RNA phage Q beta coat protein-encoding gene (C) was amplified from native Q beta RNA using a reverse transcription-PCR technique. Gene C contains sequences coding for both the 133-amino acid (aa) Q beta coat protein (CP) and the 329-aa read-through protein (A1) consisting of CP and an additional 196-aa C-terminal sequence, separated from CP within the C gene by an opal (UGA) stop codon. Primers ensuring the natural environment for gene C, especially within the ribosome-binding site, and supplying C with unique restriction sites at both ends have been prepared. An amplified 1062-bp PCR fragment was positioned under the control of the strong E. coli trp promoter (Ptrp) within a pGEM-derived plasmid. The synthesis of gene C products was confirmed electrophoretically and immunologically. An immunodiffusion test with anti-Q beta phage antibodies and electron microscopy evaluation of the purified recombinant products showed that when expressed, the Q beta C gene was responsible for high-level synthesis and correct self-assembly of Q beta CP monomers into capsids indistinguishable morphologically and immunologically from Q beta phage particles, which we plan to use as surface display vectors.

Allolevivirus↗