XCP1 cleaves Pathogenesis-related protein 1 into CAPE9 for systemic immunity in Arabidopsis

Proteolytic activation of cytokines regulates immunity in diverse organisms. In animals, cysteine-dependent aspartate-specific proteases (caspases) play central roles in cytokine maturation. Although the proteolytic production of peptide cytokines is also essential for plant immunity, evidence for cysteine-dependent aspartate-specific proteases in regulating plant immunity is still limited. In this study, we found that the C-terminal proteolytic processing of a caspase-like substrate motif "CNYD" within Pathogenesis-related protein 1 (PR1) generates an immunomodulatory cytokine (CAPE9) in Arabidopsis. Salicylic acid enhances CNYD-targeted protease activity and the proteolytic release of CAPE9 from PR1 in Arabidopsis. This process involves a protease exhibiting caspase-like enzyme activity, identified as Xylem cysteine peptidase 1 (XCP1). XCP1 exhibits a calcium-modulated pH-activity profile and a comparable activity to human caspases. XCP1 is required to induce systemic immunity triggered by pathogen-associated molecular patterns. This work reveals XCP1 as a key protease for plant immunity, which produces the cytokine CAPE9 from the canonical salicylic acid signaling marker PR1 to activate systemic immunity.

Generating high-power Lissajous structured modes and trochoidal vortex beams by an off-axis end-pumped Nd:YVO4 laser with astigmatic transformation

High-power structured beams with the transverse morphologies as the Lissajous figures are generated by an Nd:YVO₄ laser under two-dimensional off-axis pumping. By fine-tuning the cavity length in the neighborhood around the condition of longitudinal-transverse coupling, different cases of accidental degeneracies from the intracavity astigmatism are achieved to lead the output emission to be various Lissajous modes with different transverse frequency ratios. The generated Lissajous modes reveals good power performance with slope efficiency up to 47% and optical-to-optical conversion efficiency to be higher than 37.5% at a pump power of 16 W. Moreover, by applying beam transformation via a single-lens astigmatic mode converter, the generated Lissajous modes are further converted into structured vortex beams with transverse patterns localized on the trochoidal curves. The transformed trochoidal vortex beams are confirmed to preserve well-defined mode structures even when the average output power has been scaled up to be higher than 4 W.

Coding for stable transmission of W-band radio-over-fiber system using direct-beating of two independent lasers

We demonstrate experimentally Manchester (MC) coding based W-band (75 - 110 GHz) radio-over-fiber (ROF) system to reduce the low-frequency-components (LFCs) signal distortion generated by two independent low-cost lasers using spectral shaping. Hence, a low-cost and higher performance W-band ROF system is achieved. In this system, direct-beating of two independent low-cost CW lasers without frequency tracking circuit (FTC) is used to generate the millimeter-wave. Approaches, such as delayed self-heterodyne interferometer and heterodyne beating are performed to characterize the optical-beating-interference sub-terahertz signal (OBIS). Furthermore, W-band ROF systems using MC coding and NRZ-OOK are compared and discussed.

Quantitative peptidomics study reveals that a wound-induced peptide from PR-1 regulates immune signaling in tomato

Many important cell-to-cell communication events in multicellular organisms are mediated by peptides, but only a few peptides have been identified in plants. In an attempt to address the difficulties in identifying plant signaling peptides, we developed a novel peptidomics approach and used this approach to discover defense signaling peptides in plants. In addition to the canonical peptide systemin, several novel peptides were confidently identified in tomato (Solanum lycopersicum) and quantified to be induced by both wounding and methyl jasmonate (MeJA). A wounding or wounding plus MeJA-induced peptide derived from the pathogenesis-related protein 1 (PR-1) family was found to induce significant antipathogen and minor antiherbivore responses in tomato. This study highlights a role for PR-1 in immune signaling and suggests the potential application of plant endogenous peptides in efforts to defeat biological threats in crop production. As PR-1 is highly conserved across many organisms and the putative peptide from At-PR1 was also found to be bioactive in Arabidopsis thaliana, our results suggest that this peptide may be useful for enhancing resistance to stress in other plant species.

Hyperfine splitting of the 2s1/2 and 2p1/2 levels in Li- and be-like ions of (59)(141) Pr

High-resolution spectroscopy of the 2s(1/2)-2p(1/2) transition in the extreme ultraviolet region is shown to resolve the level splitting induced by the nuclear magnetic field of both the 2s(1/2) and the 2p(1/2) levels in lithiumlike (141)Pr(56+) and of the 2s(1/2)2p(1/2) (3)P(1) level in berylliumlike (141)Pr(55+). The (141)Pr ions are an ideal test of this measurement approach because their energy levels are known well from first principles and are unaffected by small energy contributions from QED and nuclear magnetization effects. The accuracy attained in the measured 196.5 ± 1.2 meV 2s(1/2) splitting is more than an order of magnitude better than that achieved before using crystal spectroscopy of the 2s(1/2)-2p(3/2) x-ray transition and at the level needed to implement a proposed scheme for disentangling the contributions from QED and nuclear magnetization effects in higher-Z ions, such as (209)Bi.

A scalable and continuous-upgradable optical wireless and wired convergent access network

In this work, a scalable and continuous upgradable convergent optical access network is proposed. By using a multi-wavelength coherent comb source and a programmable waveshaper at the central office (CO), optical millimeter-wave (mm-wave) signals of different frequencies (from baseband to > 100 GHz) can be generated. Hence, it provides a scalable and continuous upgradable solution for end-user who needs 60 GHz wireless services now and > 100 GHz wireless services in the future. During the upgrade, user only needs to upgrade their optical networking unit (ONU). A programmable waveshaper is used to select the suitable optical tones with wavelength separation equals to the desired mm-wave frequency; while the CO remains intact. The centralized characteristics of the proposed system can easily add any new service and end-user. The centralized control of the wavelength makes the system more stable. Wired data rate of 17.45 Gb/s and w-band wireless data rate up to 3.36 Gb/s were demonstrated after transmission over 40 km of single-mode fiber (SMF).

Post-translational cleavage and self-interaction of the phytoplasma effector SAP11

Phytoplasmas are insect-transmitted intracellular plant bacterial pathogens that secrete effector molecules into host cells that interfere with the host's developmental or metabolic processes. Recently, the secreted Aster Yellows phytoplasma strain Witches' Broom protein11 (SAP11) has been shown to act as a virulence factor that alters the development, hormone biosynthesis, phosphate (Pi) homeostasis, and defense responses in the affected plants. We found that SAP11 undergoes proteolytic processing in planta and self-interaction in vitro. These biochemical studies provide foundational insights necessary for the functional characterization of SAP11; however, the biological relevance of post-translational cleavage and self-interaction of SAP11 to its role as a virulence factor warrants further investigation.

Post-translational cleavage and self-interaction of the phytoplasma effector SAP11

Phytoplasmas are insect-transmitted intracellular plant bacterial pathogens that secrete effector molecules into host cells that interfere with the host's developmental or metabolic processes. Recently, the secreted Aster Yellows phytoplasma strain Witches' Broom protein11 (SAP11) has been shown to act as a virulence factor that alters the development, hormone biosynthesis, phosphate (Pi) homeostasis, and defense responses in the affected plants. We found that SAP11 undergoes proteolytic processing in planta and self-interaction in vitro. These biochemical studies provide foundational insights necessary for the functional characterization of SAP11; however, the biological relevance of post-translational cleavage and self-interaction of SAP11 to its role as a virulence factor warrants further investigation.

Transgenic plants that express the phytoplasma effector SAP11 show altered phosphate starvation and defense responses

Phytoplasmas have the smallest genome among bacteria and lack many essential genes required for biosynthetic and metabolic functions, making them unculturable, phloem-limited plant pathogens. In this study, we observed that transgenic Arabidopsis (Arabidopsis thaliana) expressing the secreted Aster Yellows phytoplasma strain Witches' Broom protein11 shows an altered root architecture, similarly to the disease symptoms of phytoplasma-infected plants, by forming hairy roots. This morphological change is paralleled by an accumulation of cellular phosphate (Pi) and an increase in the expression levels of Pi starvation-induced genes and microRNAs. In addition to the Pi starvation responses, we found that secreted Aster Yellows phytoplasma strain Witches' Broom protein11 suppresses salicylic acid-mediated defense responses and enhances the growth of a bacterial pathogen. These results contribute to an improved understanding of the role of phytoplasma effector SAP11 and provide new insights for understanding the molecular basis of plant-pathogen interactions.

Thomson scattering in the average-atom approximation

The average-atom model is applied to study Thomson scattering of x-rays from warm dense matter with emphasis on scattering by bound electrons. Parameters needed to evaluate the dynamic structure function (chemical potential, average ionic charge, free electron density, bound and continuum wave functions, and occupation numbers) are obtained from the average-atom model. The resulting analysis provides a relatively simple diagnostic for use in connection with x-ray scattering measurements. Applications are given to dense hydrogen, beryllium, aluminum, and titanium plasmas. In the case of titanium, bound states are predicted to modify the spectrum significantly.

TRPV4 mediates tumor-derived endothelial cell migration via arachidonic acid-activated actin remodeling

Changes in intracellular calcium [Ca(2+)](i) levels control critical cytosolic and nuclear events that are involved in the initiation and progression of tumor angiogenesis in endothelial cells (ECs). Therefore, the mechanism(s) involved in agonist-induced Ca(2+)(i) signaling is a potentially important molecular target for controlling angiogenesis and tumor growth. Several studies have shown that blood vessels in tumors differ from normal vessels in their morphology, blood flow and permeability. We had previously reported a key role for arachidonic acid (AA)-mediated Ca(2+) entry in the initial stages of tumor angiogenesis in vitro. In this study we assessed the mechanism involved in AA-induced EC migration. We report that TRPV4, an AA-activated channel, is differentially expressed in EC derived from human breast carcinomas (BTEC) as compared with 'normal' EC (HMVEC). BTEC display a significant increase in TRPV4 expression, which was correlated with greater Ca(2+) entry, induced by AA or 4αPDD (a selective TRPV4 agonist) in the tumor-derived ECs. Wound-healing assays revealed a key role of TRPV4 in regulating cell migration of BTEC but not HMVEC. Knockdown of TRPV4 expression completely abolished AA-induced BTEC migration, suggesting that TRPV4 mediates the pro-angiogenic effects promoted by AA. Furthermore, pre-incubation of BTEC with AA induced actin remodeling and a subsequent increase in the surface expression of TRPV4. This was consistent with the increased plasma membrane localization of TRPV4 and higher AA-stimulated Ca(2+) entry in the migrating cells. Together, the data presented herein demonstrate that: (1) TRPV4 is differentially expressed in tumor-derived versus 'normal' EC; (2) TRPV4 has a critical role in the migration of tumor-derived but not 'normal' EC migration; and (3) AA induces actin remodeling in BTEC, resulting in a corresponding increase of TRPV4 expression in the plasma membrane. We suggest that the latter is critical for migration of EC and thus in promoting angiogenesis and tumor growth.

Nondipole effects in the photoionization of xe 4d5/2 and 4d3/2: evidence for quadrupole satellites

Measurements of nondipole parameters in spin-orbit-resolved Xe 4d photoionization demonstrate dynamical differences arising from relativistic effects. The experimental data do not agree with relativistic random-phase approximation calculations of single ionization dipole and quadrupole channels. It is suggested that the discrepancy is due to the omission of multiple-excitation quadrupole channels, i.e., quadrupole satellite transitions.

Effects of Anoectochilus formosanus Hayata extract and glucocorticoid on lung maturation in preterm rats

We investigated the effects of maternal administration of Anoectochilus formosanus extract and dexamethasone on lung maturation in preterm rats. A. formosanus group mothers were tube-fed A. formosanus extract (300 mg/kg body wt./day) for 7 days from days 12-18 of gestation. Dexamethasone group mothers were injected intraperitoneally with dexamethasone (0.2 mg/kg body wt.) in saline on day 18 of gestation. Control group mothers were similarly injected with saline alone. On day 19 of gestation, fetuses were delivered by cesarean section. A. formosanus treatment significantly increased the fetal lung/body weight ratio, as compared to dexamethasone treatment. Saturated phosphatidylcholine levels in fetal lung tissue and growth hormone levels in maternal serum were significantly increased in the A. formosanus- and dexamethasone-treated groups as compared to controls. The histological appearance of preterm rat lungs revealed extensive branching of intermediate airways, denser mesenchyme, and more epithelial tubules in the dexamethasone and A. formosanus groups as compared with the control group. These results suggest that antenatal A. formosanus treatment may play a role in accelerating fetal rat lung maturation.

Dramatic nondipole effects in low-energy photoionization: experimental and theoretical study of Xe 5s

The Xe 5s nondipole photoelectron parameter gamma is obtained experimentally and theoretically from threshold to approximately 200 eV photon energy. Significant nondipole effects are seen even in the threshold region of this valence shell photoionization. In addition, contrary to previous understanding, clear evidence of interchannel coupling among quadrupole photoionization channels is found.

Free radical-scavenging activity of Taiwanese native plants

The 70% aqueous acetone extracts of ten Taiwanese native plants were evaluated by various antioxidant assays, including 1, 1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl (.OH) radicals, and reducing power assay. In the present study, extracts of Acer buerferianum var. formosanum, Cleyera japonica var. morii, Cyclobalanopsis stenophylla var. stenophylloides, and Machilus zuihoensis exhibited stronger activity against DPPH radicals, and their IC50 values ranged from 5.4 to 8.3 microg/ml. The ten selected extracts effectively inhibited the formation of .OH generated in the Fenton reaction system. Among the extracts whose reducing power activities were determined, A. buerferianum var. formosanum, C. japonica var. morii, C. stenophylla var. stenophylloides, Eriobotrya deflex, and M. zuihoensis showed high activity. The results indicate the 70% aqueous acetone extracts of A. buerferianum var. formosanum, C. japonica var. morii, C. stenophylla var. stenophylloides, and M. zuihoensis with great potency in these assay systems and may be candidates for the development of natural antioxidants.

RAPD analysis of Astragalus medicines marketed in Taiwan

The genetic variability of Astragalus medicine materials sold by twenty randomly selected stores in Taiwan was investigated using RAPD analysis in order to obtain available primers which could clearly differentiate among them. Total DNA isolated from the rhizomes of the samples were used as templates, and sixty 10 mer arbitrary primers were used in the analysis. The aim of the present study is to construct an identification model of molecular biotechniques applicable to Chinese herbal medicines in RAPD analysis. Three of the primers, OPT-03, OPT-13, and OPT-17, revealed polymorphic RAPD fingerprints among the samples of Astragalus membranaceus, and between Astragalus membranaceus and Hedysarum polybotrys samples. SSCP analysis was also conducted on PCR products from the ITS-1 region of ribosomal DNA in order to differentiate the two species.

Determination of the components in a Chinese prescription, yu-ping-feng san, by RAPD analysis

In this study, the RAPD (random amplified polymorphic DNA) technique was employed for the first time to determine the components in a Chinese herbal prescription. Forty decamer oligonucleotide primers were screened in the RAPD analysis to identify three Chinese medicines, the dried root of Astragalus membranaceus (Fisch.) Bge., the dried root of Ledebouriella seseloides Wolff, and the dried rhizome of Atractylodes macrocephala Koidz, in a Chinese prescription. Only primer OPP-10 simultaneously generated three distinct markers were each specific to one component. The marker with 200 bp is specific to Astragalus membranaceus; the 440 bp marker is specific to Atractylodes macrocephala; and the remaining marker with 500 bp was present in Ledebouriella seseloides. The presence of the three herbal medicines in the mixed sample, the Chinese prescription, was determined when the primer OPP-10 RAPD reaction was performed. The technique was proved to contribute to the identification of components in the Chinese medicinal preparations.

Differentiation of genuines and counterfeits of Cordyceps species using random amplified polymorphic DNA

For identification of genuine and counterfeit samples of Cordyceps sinensis, an RAPD (random amplified polymorphic DNA) analysis was performed. In the study, twelve samples were collected, of which six were genuine and six were counterfeit samples. Genuine samples of Cordyceps sinensis contain two parasitic larvae produced from each of the three provinces, Sichuan (SC), Chinghai (CH), and Tibet (TB). The counterfeits contain two products of each of the three species, Cordyceps hawkesii, Stachys geobombycis, and Stachys sieboldii. In the RAPD analysis, twenty arbitrary decamer primers were screened to obtain primers appropriate for differentiating the genuine and counterfeit samples. The result of twelve RAPD markers generated from four primers, OPT-08, OPT-12, OPT-13, and OPT-17, were selected. The primers can easily distinguish between genuine and counterfeit samples of Cordyceps sinensis.

Identification of Anoectochilus formosanus and Anoectochilus koshunensis species with RAPD markers

RAPD (random amplified polymorphic DNA) markers were developed to distinguish Anoectochilus formosanus from Anoectochilus koshunensis and their putative hybrids. Morphological differentiation of these two species beyond the flowering period is difficult. RAPD markers provide a rapid and easy tool for identification of the two Anoectochilus species. In the study, forty arbitrary decamer primers were screened, and nineteen species-specific RAPD markers generated from polymerase chain reactions (PCR) with eight random primers were obtained. Nine were specific to A. formosanus and ten to A. koshunensis. Two primers, OPC-08 and OPL-07, produced two markers, one specific to A. formosanus and the other specific to A. koshunensis, which simultaneously appeared in the hybrids pattern. The RAPD markers can be applied both to identification of A. formosanus and A. koshunensis species and to assessment of the extent fo hybridization in hybrids between them. This information facilitates the breeding program process.

Ultratag RBC kit for combined cardiac first-pass and multigated acquisition studies

The authors developed a procedure to use the in vitro Ultratag (Mallinckrodt, St. Louis, MO) red blood cell (RBC) labeling kit for both first-pass (FP) and multigated acquisition (MUGA) studies with a high specific activity in a reduced volume (50 mCi/0.5 ml) and a high labeling efficiency that can be used with a single-crystal camera to yield a quality study.

METHODS

A packed red blood cell (PRBC) bolus was created by two methods: (a) reducing the volume of the components of the Ultratag kit and (b) centrifuging the final dose volume. The labeling efficiency of each bolus was evaluated, each PRBC bolus was visually inspected for clots and percent hemolysis was assessed using a hemocytometer at 30 min, 1 hr and 2 hr postcentrifugation.

RESULTS

Use of the first method, the 50% kit, provided the best results. However, the resulting volume from this kit only approached 1 ml, which is not clinically adequate for a first-pass study. In the second method, the total volume was centrifuged to form a PRBC bolus, which appeared to be stable in the syringe for at least 2 hr. A combined FP/MUGA study from a centrifuged 50% reduced kit was performed in one normal subject as a preliminary assessment of the clinical utility of this procedure. The image quality of the scan is diagnostically adequate.

CONCLUSION

By using the in vitro Ultratag kit, a compact PRBC bolus was created that was stable in the syringe and could be reinjected safely into the patient for combined cardiac FP/MUGA studies.

Biodistribution and radioimmunopharmacokinetics of 131I-Ama monoclonal antibody in atherosclerotic rabbits

Monoclonal antibodies have been raised against Ama isolated from human and experimental atherosclerotic plaque. 131I-Ama-MoAb in the whole antibody form was injected into normal NZW rabbits and Watanabe hyperlipidemic rabbits. Biodistribution studies showed that atheromatous aortas had a significantly higher (5-7X) uptake of 131I-Ama-MoAb than that of normal aortas. However, 131I-Ama-MoAb was cleared very slowly from atherosclerotic rabbits. As a result, atheromas could not be identified by imaging because of the low target to non-target ratios.

Animal study of phoenix total artificial heart implantation

BACKGROUND

It is well accepted that a total artificial heart (TAH) can be used as a bridge to heart transplantation during the waiting period for organ donation. A series of combined studies, conducted by the Kaohsiung Veterans General Hospital, National Yang-Ming Medical College and Municipal Tainan Hospital, has been performed to improve the Phoenix artificial heart developed by Dr. Kevin Kuo-Tsai Cheng.

METHODS

In growing calves (weighed about 80 kg), standard procedures were used to remove the hearts and replace them with the TAHs. Records were made of hemodynamic data, physiological responses, blood biochemistry data and physical activities after operation and until the death of the calves. Finally, autopsies were used to determine the causes of death.

RESULTS

A total of 23 calves were studied. Twenty-two of them survived 1 to 12 days, or an average 4.95 days. One survived more than 30 days. All the calves could breathe, stand, eat and void by themselves two hours after operation. Respiratory failure was the major cause of death.

CONCLUSIONS

No thrombus within the TAH was noted in the last five cases, meaning that turbulent flow or dead space of the TAH was improved. Better intensive care and prevention of infection will be the next challenge for long-term use of TAH.

Chorionic villi sampling: laboratory experience with 4,000 consecutive cases

Experience with 4,000 consecutive CVS cases shows that 1) the combination of both the direct and culture methods greatly reduces false diagnoses and maternal cell contamination; 2) the time interval between the sampling procedure and processing of villus specimens influences the quality of direct preparations; 3) maternal cell contamination (MCC) can be minimized with dissection of CVS specimens. We have compiled a large volume of confined placental mosaicism (CPM) cases to serve as a resource in interpreting mosaic cytogenetic findings. It was noted that, in up to 92% of the mosaic cases, the abnormal cell line was confined to the placenta. The frequency of true chromosomal mosaicism was 0.2%, and is not different from that for amniocentesis.

Innovative nuclear pharmacy service. A comprehensive management plan for clinical investigations

OBJECTIVE

To provide an overview of the investigational nuclear pharmacy service at the Medical University of South Carolina.

DATA SOURCES

References were selected from published bibliographies of nuclear pharmacy and hospital pharmacy articles and from specific-topic searches of the MEDLINE computerized database (all languages, through 1992).

STUDY SELECTION

Studies of clinical pharmacy functions that were considered relevant to the specialty practice of nuclear pharmacy were chosen.

DATA EXTRACTION

Studies were reviewed for internal consistency and appropriateness.

DATA SYNTHESIS

Data on the clinical impact of nuclear pharmacy services do not exist.

CONCLUSIONS

Based on our experience in establishing an investigational drug service, we conclude that nuclear pharmacists should take an active role in clinical investigations. The outcomes of this kind of involvement are very rewarding.

A study of the concept of non-radioactive unit-dosed reagent kits [cold unit doses (CUDs)] as an efficient and cost-saving method for 99mTc radiopharmaceutical preparation

Traditionally, when preparing 99mTc-labeled radiopharmaceuticals, [99mTc]pertechnetate is added to the entire contents of a vial of reagent kit, and patient doses are subsequently withdrawn from the vial. This technique of compounding can be potentially wasteful for two reasons: (1) once reconstituted with 99mTc, most reagent kits have a relatively short shelf-life, and thus the entire contents may not be used before expiration and (2) due to a need to conserve radioactivity in many hospitals, enough [99mTc]pertechnetate is added to the reagent kit in order to retrieve only 1-2 patient doses, even though adequate chemicals (ligand, reducing agent, etc.) are present in the reagent kit to supply as many as 5-10 doses. Hence, a method for optimizing the efficient use of reagent kits would be desirable. The purpose of this study was to determine the feasibility of unit-dosing non-radioactive reagent kits and storing these cold unit doses (CUDs) for eventual labeling with 99mTc. To evaluate this concept, unit doses were prepared from reagent kits of medronate (MDP) and pentetate (DTPA). The specific variables studied in this research were the effects of storage time, storage temperature and reconstitution volume (dilution) on the unit doses. These effects were monitored by measuring the radiochemical and biodistribution properties of the unit doses following their final reconstitution with [99mTc]pertechnetate. The labeling efficiency was determined using instant thin layer chromatograph (ITLC), and the biodistribution patterns of these radiolabeled CUDs were studied in mice. The results showed the MDP- and DTPA-CUDs stored at -18 degrees C retained the properties which resulted in acceptable radiochemical purity and biodistribution in mice for as long as 30 days. On the other hand, the radiochemical purity of MDP and DTPA unit doses stored at 25 degrees C deteriorated rapidly. Mean radiochemical purities as low as 0.58-19.4% were observed on day 30. Altered biodistributions were observed in a manner consistent with the decreased labeling efficiencies. The CUDs of lower dilution (3 mL) appeared to be more stable than the CUDs of higher dilution (10 mL). However, the effect of reconstitution volume was much less significant than the temperature effect on the CUDs. In conclusion, the concept of unit-dosing non-radioactive reagent kits appears to provide an efficient and cost-saving method for preparing infrequent and emergency radiopharmaceutical doses. The study also showed that the storage temperature of these unit doses is critical to the success of the procedure. The volume of reconstitution has a minimal impact on the stability of CUDs if stored at the appropriate temperature.

Preparation and storage of single-dose portions of exametazime: effects on radiochemical purity after labeling

The effect of exametazime concentration, storage time, and the volume of the radiolabeling compound on the radiochemical purity of labeled exametazime doses was studied. Exametazime cold unit doses (CUDs) of 0.50, 0.33, 0.25, 0.17, and 0.13 mg/mL were prepared by reconstituting exametazime kits with 0.9% sodium chloride injection. After either one or two days of storage at -10 degrees C, four CUDs of each concentration were labeled with 0.2-0.3 mL of sodium pertechnetate Tc 99m (10-20 mCi). The radiochemical purity of CUDs was evaluated 15 minutes later by instant thin-layer chromatography. In a second experiment, exametazime CUDs of 0.5 mg/mL were prepared. After 0-19 days of storage at -10 degrees C, four CUDs were each labeled with 0.2 mL of sodium pertechnetate Tc 99m (10-20 mCi), and radiochemical purity was measured after 15 minutes. In a third experiment, exametazime CUDs of 0.5 mg/mL were labeled with 2.0 mL of sodium pertechnetate Tc 99m (10-20 mCi) after zero to five days of storage at -10 degrees C. The mean radiochemical purity was unacceptably low (less than 80%) for exametazime CUDs of 0.33, 0.25, 0.17, and 0.13 mg/mL; the 0.5-mg/mL CUDs were acceptably stable. Purity was less than 80% for CUDs stored for more than two days. The radiochemical purity of CUDs labeled with 2.0 mL of sodium pertechnetate Tc 99m was significantly greater than the purity of CUDs labeled with 0.2 mL for storage times exceeding two days.(ABSTRACT TRUNCATED AT 250 WORDS)

The production and evaluation of contrast-carrying liposomes made with an automatic high-pressure system

An automatic, high-pressure system (Microfluidizer) has been found useful for producing contrast-carrying liposomes on an industrial scale. The goal of this investigation was to determine the feasibility of using this new microemulsification process to manufacture contrast-carrying microemulsified liposomes (MELs). Seven contrast media (three ionic, four nonionic) were encapsulated into the MELs. Light and electron microscopy, light scattering, radioisotope, and CT scan techniques were used to characterize these MELs, and the contrast entrapments among the studied media were compared. The contrast-carrying MELs had good properties for imaging normal reticuloendothelial tissues, selectively. They had a narrow size range (0.1-3.0 micron), a single bilayer wall, high liver and spleen upake, and low leakage rates. The nonionic media were significantly more effectively entrapped in the MELs than the ionic media (P less than .05). The iodine-to-lipid weight ratio was about 1:16 for ionic media and 1:4 for nonionic media. Physical properties of the contrast media such as osmotic pressure and charge appeared to affect contrast entrapment. It was concluded that the microemulsification process is a useful system for producing contrast-carrying liposomes continuously, on a large scale and in a reproducible manner.

Influence of complex charge and size on the uptake of 99mTc-diphosphonates in osteogenic tissue

The biodistributions of six chromatographically pure 99mTc-HEDP complexes have been determined in soft tissues, normal bone and osteogenic lesions (induced with a Walker 256 tumor) in Fisher 344 rats. The physical properties of each 99mTc-HEDP complex including anionic charge, partial molar volume, molecular weight and spectral characteristics are known; thus allowing structure-activity relationships to be drawn. The results indicate that the smallest, low charged, mononuclear 99mTc-HEDP complexes have the greatest uptake in bone lesions, and the highest lesion to muscle and lesion to normal bone ratios.