Giant anisotropic photocurrent modulated by strain in Weyl semimetal Td-MoTe2.

We built a Cu-MoTe2-Cu device model and used first-principles density functional theory to study the transport properties of the Td-MoTe2 heterojunction. We obtained the effect of strain on the energy band structure of the bulk Td-MoTe2, the transport properties, and photocurrent of the Cu-MoTe2-Cu device. The strain-induced photocurrent shows an anisotropy that reflects the modulation of the energy bands, including the Weyl point, by strain. The photocurrent can be suppressed to almost zero when the strain is applied along the vacuum direction. In contrast, the photocurrent can be significantly increased when the strain is applied along the transport direction. The transport properties and magnitude of the photocurrent in the MoTe2-based device can be effectively modulated by adjusting the strength and direction of the strain.

CT findings of adrenal schwannoma.

AIM: To analyse the computed tomography (CT) imaging features of patients with adrenal schwannoma. MATERIALS AND METHODS: Eight cases of adrenal schwannoma confirmed by histopathology were included in this study. All eight patients had undergone multiphase CT examinations. The features of the adrenal schwannoma in the CT images were analysed retrospectively in detail, including size, shape, margin, radiodensity, calcification, and enhancement pattern. RESULTS: There were six male and two female patients, with a median age of 44.5 years (range, 25-52 years). Two patients complained of right flank pain, and two with left upper abdominal discomfort, while the remaining patients were diagnosed by routine ultrasound examinations. On unenhanced CT images, all cases of adrenal schwannoma were well circumscribed, rounded or oval, heterogeneous masses with cystic components, with two cases exhibiting calcification, and three cases with septa. On enhanced CT images, all cases displayed mild heterogeneous enhancement of the tumour during the arterial phase, and progressive enhancement during the portal venous phase and equilibrium phase. CONCLUSION: Adrenal schwannoma commonly presents as a well-defined unilateral mass with cystic degeneration, septa, and a characteristic progressive contrast-enhancement pattern on multiphase enhanced scans.

Efficacy of phytoestrogens for menopausal symptoms: a meta-analysis and systematic review.

OBJECTIVE: To perform a meta-analysis examining the efficacy of phytoestrogens for the relief of menopausal symptoms. METHODS: Medline, Cochrane, EMBASE, and Google Scholar databases were searched until September 30, 2013 using the following key words: vasomotor symptoms, menopausal symptoms, phytoestrogens, isoflavones, coumestrol, soy, red clover. Inclusion criteria were (1) randomized controlled trial (RCT), (2) perimenopausal or postmenopausal women experiencing menopausal symptoms, (3) intervention with an oral phytoestrogen. Outcome measures included Kupperman index (KI) changes, daily hot flush frequency, and the likelihood of side-effects. RESULTS: Of 543 potentially relevant studies identified, 15 RCTs meeting the inclusion criteria were included. The mean age of the subjects ranged from 49 to 58.3 and 48 to 60.1 years, respectively, in the placebo and phytoestrogen groups. The number of participants ranged from 30 to 252, and the intervention periods ranged from 3 to 12 months. Meta-analysis of the seven studies that reported KI data indicated no significant treatment effect of phytoestrogen as compared to placebo (pooled mean difference = 6.44, p = 0.110). Meta-analysis of the ten studies that reported hot flush data indicated that phytoestrogens result in a significantly greater reduction in hot flush frequency compared to placebo (pooled mean difference = 0.89, p < 0.005). Meta-analysis of the five studies that reported side-effect data showed no significant difference between the two groups (p = 0.175). CONCLUSION: Phytoestrogens appear to reduce the frequency of hot flushes in menopausal women, without serious side-effects.

Guiding infrared electromagnetic waves through TI nanowires with extremely large wavenumber and azimuthal index.

In this paper, the dispersion relations of the surface plasmon polaritons (SPPs) in TI nanowires have been investigated. For simplicity, TI nanowire has been modeled as a dielectric cylinder with a conductive surface, the conductivity of which is an anti-symmetric tensor. The off-diagonal terms of the conductivity tensor only slightly change the dispersion relations. Due to small conductivities, these SPPs have extremely large wavenumbers and azimuthal indices; the electric fields are tightly confined near the conductive surface. For high-order modes, cut-off phenomena have been observed. In the end, the effects of losses and much larger bulk permittivities on the dispersion relations of surface plasmons have been discussed. The simple model proposed in this paper can be directly applied to other materials with arbitrary surface conductivity. Our investigations show that TI nanostructures are promising platforms for nanophotonic applications in the future.

Plasmonic detection of the parity anomaly in a two-dimensional Chern insulator.

In this paper, we present an analytic study on the surface plasmon polaritons in a two-dimensional parity anomaly Chern insulator. The two-dimensional conductivities derived from the BHZ model are antisymmetric, based on which two surface plasmon modes each contains two branches of dispersions have been found. In the absence of parity anomaly, the half-integer-valued Hall conductivities with positive and negative Dirac mass terms differ by a sign; two branches of each surface plasmon mode are exactly degenerate. However, the parity anomaly can lift such degeneracy and lead to significant modifications of these dispersion curves or even the occurrence of an extra branch of surface plasmons under particular condition. Our investigations have revealed the effects of the interplay of parity anomaly and topology on the dispersion relations of the surface plasmon polaritons, which may pave a possible way for the detection of the parity anomaly in a two-dimensional Chern insulator via plasmonic responses.

Analysis of the role of hMLH1 hypermethylation and microsatellite instability in meningioma progression.

We investigated a possible role of hMLH1 hypermethylation and microsatellite instability in meningioma progression. Fifty meningomas were examined for methylation of hMLH1 using a methylation-specific PCR; 43 of them were analyzed for microsatellite instability using nine microsatellite markers. Loss of heterozygosity on chromosome 22q was detected using two markers. Two atypical meningiomas showed microsatellite instability at four loci; one was methylated on hMLH1 and the other was unmethylated. Nine meningiomas were found to have methylated hMLH1; the frequencies in the different grades of meningioma were one of 20, two of 16, and six of 14, respectively. We concluded that the methylation status of hMLH1 is associated with the meningioma grade but not with microsatellite instability. Loss of heterozygosity was detected in 22 cases in at least one marker. The frequency of loss of heterozygosity increased with meningioma grade, but the tendency was not significant. The correlation between loss of heterozygosity and methylation of the hMLH1 gene was also not significant. We conclude that hypermethylation of the promoter of hMLH1 is an epigenetic change in meningiomas and is associated with the tumor grade, while microsatellite instability is an uncommon event in meningiomas.

Surface plasmons in anisotropic 3D gapped topological insulators.

Topological insulators (TIs) are materials having conductive surfaces but insulating bulk, which are ideal platforms for plasmonic applications. The most commonly known TIs, such as Bi2Se3and Bi2Te3, are in fact highly anisotropic. The dielectric constants are largely different parallel and perpendicular to the surface. Here, we have extended the electromagnetic calculations of the surface plasmons in TIs to the anisotropic case. Magnetic field perpendicular to the surface is allowed, which opens a gap among the surface states. We model anisotropic TIs as bulk dielectric materials with different in-plane and out-of-plane permittivities; the surface states caused by the band inversion lead to a two-dimensional conductivity which supports surface plasmons. We have found two rather than one surface modes. Due to such anisotropy, quasi transverse electric (TE) polarized mode may occur near the interband transition threshold. Far below the transition frequency, another mode with both TE and transverse magnetic polarized components dominates, the dispersion relation of which is seriously modified by the Hall conductivity. By taking Bi2Te3as an example, we have derived the conductivity tensor with the consideration of the hexagonal warping effect, and solved the above mentioned two surface plasmon modes. In the end, finite element method has been used to calculate the electric field distributions. Our extension of the electromagnetic calculations of surface plasmons including a specific kind of anisotropy might be useful in other surface conductive materials with similar symmetry as well.

[Analysis of lactate dehydrogenase gene polymorphisms and prediction of B cell epitopes in four human Plasmodium species].

OBJECTIVE: To analyze the polymorphism of Plasmodium lactate dehydrogenase (pLDH) gene and predict B-cell epitopes in pLDH peptides in four species of human malaria parasites. METHODS: The blood samples and epidemiological characteristics were collected from malaria cases in Yunnan Province registered in the National Notifiable Disease Report System. The pLDH genes of four human Plasmodium species were amplified using nested PCR assay and sequenced. The polymorphisms of pLDH genes was analyzed using the software MEGA version 7.0.26 and DnaSP version 5.10, and the B-cell epitopes were predicted in pLDH peptides using the Immune Epitope Database (IEDB). RESULTS: The sequences of P. vivax LDH (PvLDH), P. falciparum LDH (PfLDH), P. ovale LDH (PoLDH) and P. malariae LDH (PmLDH) genes were obtained from 153, 29, 17 and 11 blood samples from patients with P. vivax, P. falciparum, P. ovale and P. malariae malaria, respectively, which included 15, 2, 4 and 2 haplotypes and had a nucleotide diversity (π) of 0.104. A high level of intra-species differentiation was seen in the PoLDH gene (π = 0.012), and the π values were all < 0.001 for PvLDH, PfLDH and PmLDH genes. Active regions of B-cell antigen were predicted in the pLDH peptide chain of four human malaria parasites, of 4 to 5 in each chain, and the activity score was approximately 0.430. Among these peptide chains, the "86-PGKSDKEWNRD-96" short-peptide was a B-cell epitope shared by all four species of human malaria parasites, and the "266-GQYGHS (T)-271" short-peptide was present in PvLDH and PoLDH peptide chains, while "212-EEVEGIFDR-220" was only found in the PvLDH peptide chain, and "208-LISDAE-213" was only seen in the PfLDH peptide chain. CONCLUSIONS: The PoLDH gene polymorphism may be derived from the weak negative purification selection, while PvLDH, PfLDH and PmLDH genes may maintain a relatively conservative state. There may be two B-cell epitopes "212-EEVEGIFDR-220" and "208-LISDAE-213" in the proximal region of the C terminal in the pLDH peptide chain, which is feasible to differentiate between P. vivax and P. falciparum infections.

Photosynthesis in response to salinity and submergence in two Rhizophoraceae mangroves adapted to different tidal elevations.

Mangrove ecosystems are vulnerable to rising sea levels. When the sea level rises, the plants are exposed to increased salinity and tidal submergence. In Taiwan, the mangrove species Kandelia obovata and Rhizophora stylosa grow in different habitats and at different elevations. To understand the response of photosynthesis to salinity and submergence in mangroves adapted to different tidal elevations, gas exchange and chlorophyll fluorescence parameters were measured in K. obovata and R. stylosa under different salinity (20 and 40‰) and submergence treatments. The period of light induction of photosynthesis for the two mangrove species was >60 min. In the induction process, the increase in photosystem efficiency was faster than the increase in stomatal opening, but CO2 fixation efficiency was restricted by stomatal conductance. The constraint of stomatal opening speed is related to the conservative water-use strategy developed in response to mangrove environments. Submergence increased the photosynthetic rate of K. obovata, but not that of R. stylosa. Although R. stylosa was more salt tolerant than K. obovata, R. stylosa was not submergence tolerant in a high-salinity environment, which may be the reason for the higher intertidal elevations observed for R. stylosa in comparison with K. obovata. The photosynthetic rate and energy-dependent quenching (qE) of the two mangroves presented a negative relationship with photoinhibition, and high-salt treatment simultaneously reduced photosynthetic rate and qE. A decrease in the photosynthetic rate increased excess energy, whereas a decrease in qE decreased photoprotection; both increased photoinhibition. As the degree of photoinhibition can be easily measured in the field, it is a useful ecological monitoring index that provides a suitable reference for mangrove restoration, habitat construction and ecological monitoring.

Expression of aquaporin-4 in human supratentorial meningiomas with peritumoral brain edema and correlation of VEGF with edema formation.

Peritumoral brain edema is a common complication of meningiomas. It is believed that vascular endothelial growth factor (VEGF), as an angiogenic factor, plays a vital role in edema formation. Aquaporin-4 (AQP4) is a small integral membrane protein that regulates water in the normal brain. However, the expression of AQP4 and its relationship to VEGF in edematous meningiomas are not well known. We studied tumor specimens of 59 human supratentorial meningiomas. Western blot analysis was used to detect the expression of AQP4, and double-labeling immunofluorescence histochemical staining was performed to determine the relationship between AQP4 and VEGF. The AQP4 expression was significantly higher in the edema group, in which the protein level was correlated with the extent of edema. Greater VEGF expression was also observed in the edema group, and a relationship between AQP4 and VEGF was found. We conclude that AQP4 is involved in peritumoral brain edema formation in meningiomas and is also closely related to the expression of VEGF.

Topological hybrid semimetal phases and anomalous Hall effects in a three dimensional magnetic topological insulator.

In this work, we propose a ferromagnetic Bi2Se3as a candidate to hold the coexistence of Weyl- and nodal-line semimetal phases, which breaks the time reversal symmetry. We demonstrate that the type-I Weyl semimetal phase, type-I-, type-II- and their hybrid nodal-line semimetal phases can arise by tuning the Zeeman exchange field strength and the Fermi velocity. Their topological responses under U(1) gauge field are also discussed. Our results raise a new way for realizing Weyl and nodal-line semimetals and will be helpful in understanding the topological transport phenomena in three-dimensional material systems.

Pre-treatment quality of life as a predictor of distant metastasis-free survival and overall survival in patients with head and neck cancer who underwent free flap reconstruction.

PURPOSE: This study examined the prognostic associations of pre-treatment quality of life (QoL) with overall survival (OS) and distant metastasis-free survival (DFMS) among patients with head and neck cancer (HNC) who underwent free flap reconstruction. METHODS: A cohort of 127 HNC patients who received free flap reconstruction between November 2010 and June 2014 at a hospital were recruited. Pre-treatment QoL was measured by the University of Washington Quality of Life Questionnaire, which contains six physical domains, including speech, swallowing, appearance, saliva, taste and chewing, as well as the six social-emotional domains of pain, activity, recreation, shoulder, mood, and anxiety. Cox regression analyses were performed. RESULTS: Results showed that pre-treatment QoL was predictive of OS and DMFS. Of the domains, swallowing, chewing, speech, taste, saliva, pain and shoulder were demonstrated to be significant predictors of OS. Additionally, swallowing, chewing, speech, pain and activity were demonstrated making significant contributions to DMFS. CONCLUSION: Our data supported that physical domains of pre-treatment QoL were predictors for OS and DFMS in HNC patients with free-flap reconstruction. Longitudinal studies are warranted to clarify the prognostic abilities of social-emotional domains. Information on pre-treatment QoL should be taken into account to individualize care plan for these patients, and hence prolong their survival.

[Neoadjuvant chemotherapy of invasive cancer of the urinary bladder].

We studied efficacy of a combination of intraosseous and systemic administration of drugs in patients with invasive cancer of the urinary bladder (UB). A total of 20 patients aged 54-79 years with verified had recurrence, 2 had tumors with continuous growth. T2N0M0 UB carcinoma was diagnosed in 7 patients, T3N0M0--in 12, T6N0M0--in 1 patient. All the patients received systemic chemotherapy with gemzar in a single daily dose 800-1000 mg/m2 on day 1, 7 and 14. On day 2 a single intraosseous 100 mg eloxatin was given. A total of three courses of combined chemotherapy with 4-week interval was used. Intravenous gemzar administration was accompanied with mild leukopenia in 4 patients, moderate leukopenia--in 1, allergic reaction--in 2 patients. This required gemzar discontinuation. No side effects were seen in response to intraosseous administration of eloxatin. The combined chemotherapy produced complete regression of UB cancer in 3 of 18 patients, partial regression--in 12, stabilization--in 3 patients. Neither local nor long-term tumor progression was found. Short-term therapeutic efficacy of combined therapy was 70%. Fifteen patients with partial regression or stabilization have undergone transurethral resection. Duration of a recurrence-free period reached 5 to 72 months (mean 17 months). The neoadjuvant chemotherapy proposed by us allows achievement of a high percentage of regression in patients with invasive UB cancer located in UB cervix and provides concervative surgery including patients over 70 years of age.

Topological phases of the kicked Harper-Kitaev model with ultracold atoms.

We propose using ultracold atoms trapped in a one-dimensional periodically driven optical lattice to realize the Harper-Kitaev model, where the on-site energies are periodically kicked. Such a system provides a natural platform to study both Chern insulators and Majorana fermions. Based on calculating the quasienergy spectra, we find that both Floquet Majorana modes and Hall chiral edge modes could appear at the sample boundary in the gaps between the quasienergy bands. We also study the competition of topological superconductor and Chern insulator states in the model. We calculate the [Formula: see text] index and Floquet Chern number to characterize the above two different topological states, including the topological phase transitions in the kicked Harper-Kitaev model with the increase in the strength of the kick.

The zinc-finger transcriptional factor Slug transcriptionally downregulates ERα by recruiting lysine-specific demethylase 1 in human breast cancer.

Estrogen receptor α (ERα) is related with epithelial-mesenchymal transition, invasion and metastasis, and serves as an important therapeutic predictor and prognostic factor in breast cancer patients. The triple negative breast cancer (TNBC) is characterized by loss of hormone receptors and human epidermal growth factor receptor 2 (Her2), and lacks effective targeted therapy with poor prognosis. Unfortunately, the molecular mechanisms of ERα deficiency, which becomes hormone independent and results in resistance to endocrine therapy, remain to be elucidated in breast cancer. In this study, we observed an inverse correlation between Slug, a zinc-finger transcriptional repressor, and ERα expression in both human breast cancer tissues and cell lines. In ERα-negative breast cancer patients, high Slug messenger RNA expression showed obviously shorter relapse-free survival. We found that Slug binds to the E-box located in the promoter of estrogen receptor 1 gene (ESR1) to suppress its expression. More specifically, Slug recruits lysine-specific demethylase 1 (LSD1) to the E-box and thereby inhibits ERα expression by demethylating H3K4me2, which is evidenced by the interaction between Slug and LSD1. Moreover, the amount of H3K4me2 binding to the E-box was significantly increased after LSD1 knockdown in MDA-MB-231 cells. Functionally, the ability to proliferate, invade and metastasize was significantly suppressed after knockdown of either Slug or LSD1 alone, or both simultaneously. Taken together, these results suggest that Slug transcriptionally inhibits ERα expression by recruiting LSD1 to the ESR1 promoter in breast cancers. Thus, targeted inhibition of Slug and LSD1 may restore ERα and lead to resensitization to hormone therapy, providing a novel therapeutic strategy for ERα-negative breast cancer patients, especially for TNBC.

Hepatic artery injection of Yttrium-90-lipiodol: biodistribution in rats with hepatoma.

UNLABELLED: In this study, we analyzed the biodistribution of 90Y-lipiodol in rats with liver tumors (hepatoma) following hepatic arterial injection. METHODS: Sixteen male Sprague-Dawley rats with liver tumors were killed at 1, 24, 48 and 72 hr (four rats at each time) after injection of approximately 0.1 mCi 90Y-lipiodol through the hepatic artery, respectively. Samples of tumor, liver, spleen, skeletal muscle, lung, kidney, bone, whole blood and testis were obtained and counted to calculate the tissue concentrations (%ID/g). RESULTS: We found that the radioactivity in the liver tumor was high at 1 and 24 hr and then declined slowly. The biological half-time was 84.1 hr. The radioactivity in normal liver tissue was also high at 1 hr but was significantly lower than that in the tumor. The biological half-time was 38.5 hr. The ratio of tissue concentration between liver tumor and normal liver tissue (T/N ratio) was 3.03 at 1 hr and rose to 6.45 at 72 hr. The radioactivity in the lung was almost as high as in normal liver tissue at 1 hr and declined rapidly with a biological half-time of 25.6 hr. The activity levels of the kidney were moderate at 1 hr and remained at almost the same level throughout the study. A moderate concentration of radioactivity in bone was noted within the first 24 hr. The concentration, however, rose over the ensuing time. The concentration of radioactivity in skeletal muscle, spleen, testis and whole blood was quite low. CONCLUSION: Following hepatic arterial injection of 90Y-lipiodol, tracer uptake in liver tumor was high and tumor retention was lengthy. Consequently, large radiation doses could be delivered to the tumor. We suggest that 90Y-lipiodol is a potential agent in the treatment of liver malignancy.

Intratumoral injection of rhenium-188 microspheres into an animal model of hepatoma.

UNLABELLED: Intratumoral injection of 90Y microspheres is a potential alternative in the treatment of primary liver tumor. However, complicated preparation and lack of a gamma ray for imaging are the disadvantages of 90Y. In this study, we used 188Re, a generator-produced radioisotope with 155-keV gamma ray emission, to label microspheres. After intratumoral injection of 188Re microspheres into rats with hepatoma, biodistributions and survival times were analyzed. METHODS: Twelve male rats with hepatoma were killed at 1, 24 and 48 hr (4 rats at each time point) after intratumoral injection of approximately 7.4 MBq 188Re microspheres. Samples of various organs were obtained and used to calculate the tissue concentrations. In addition, 30 male rats bearing hepatoma were divided into two groups (15 rats in each group) to evaluate survival time. Group 1 received intratumoral injection of 37 MBq 188Re microspheres, whereas Group 2 served as the control group and received an intratumoral injection of 0.1 ml normal saline only. Survival time was calculated from the day of injection to 2 mo after treatment. RESULTS: Radioactivity in the tumor was very high throughout. Biological half-time was 170.8 hr. Radioactivity in the lung was 1.78% injected dose (i.d.)/g at 1 hr but declined rapidly over time. The concentration in the urine was approximately 6.14% i.d./ml after the first hour and rapidly declined thereafter. The concentrations of radioactivity in other organs, such as normal liver, muscle, spleen, bone, testis and whole blood, were quite low throughout the study. Twelve of 15 (80%) of rats survived over 60 days after intratumoral injection of 188Re microspheres, whereas only 4 of 15 (26.7%) survived more than 60 days after injection of normal saline only. The difference between the groups was significant (p < 0.05). CONCLUSION: Rhenium-188 offers cost-effectiveness, on-site availability, short half-life, energetic beta particle, emission of gamma photons for imaging, easy preparation, easy clinical administration and apparent lack of radiation leakage from the treated tumor. Direct intratumoral injection of 188Re microspheres is extremely attractive as a clinical therapeutic alternative in hepatoma patients.

Histologic study of effects of radiation synovectomy with Rhenium-188 microsphere.

Rhenium-188 microsphere is a relatively new radiation synovectomy agent developed for the treatment of rheumatoid arthritis. It has been shown that the levels of unwanted extra-articular radiation are negligible with this agent. A histologic study was conducted to assess the effect of radiation synovectomy on synovium and articular cartilage after intra-articular injection of various doses of Re-188 microspheres into the knee joints of rabbits. Intra-articular injection of Re-188 microspheres into rabbit knee joints resulted in mild reactive inflammation and thrombotic occlusion of vessels which subsided rapidly. Sclerosis of subsynovium could be seen 12 weeks after injection. No evidence of damage to articular cartilage was noted. There was no significant difference in the articular pattern after injection of 0.3 or 0.6 mCi Re-188 microspheres. This study suggests that a treatment dose of Re-188 microspheres causes transient inflammation of synovium without any detectable damage to the articular cartilage of knee joint.

Effects of alternative reconstitution procedures on the labelling efficiency and in vitro stability of 99Tcm-labelled radiopharmaceuticals.

Adding normal saline (NS) separately before 99Tcm-sodium pertechnetate to MDP cold kits has been shown to reduce substantially the radiation dose to the hand. A similar dose reduction will probably prove to be valid with the preparation of most other 99Tcm-labelled radiopharmaceuticals. However, it is unknown how this altered reconstitution procedure may affect the labelling efficiency and in vitro stability of the 99Tcm-labelled radiopharmaceuticals. We have evaluated the effects on the labelling efficiency and in vitro stability of 99Tcm-labelled MDP, mertiatide and sestamibi reconstituted with three different methods: adding normal saline before 99Tcm activity (NS/Tc); adding 99Tcm activity before normal saline (Tc/NS); and the standard reconstitution method of adding both 99Tcm activity and normal saline together. The labelling efficiency and in vitro stability were evaluated by measuring the radiochemical purity of each radiopharmaceutical tested at 0, 1, 3, 6, 12 (except 99Tcm-MDP) and 24 h after reconstitution. For 99Tc-mertiatide, there was a very slight difference in the labelling efficiency, mostly due to the Tc/NS method being approximately 0.29% lower across time post-reconstitution than the standard method. For 99Tcm-labelled MDP and sestamibi, there were no differences between the three methods in terms of labelling efficiency and in vitro stability. In conclusion, both alternative methods (i.e. NS/Tc and Tc/NS) appear not to have any detrimental effect on the labelling efficiency and in vitro stability of the 99Tcm-labelled radiopharmaceuticals that we tested. However, of the two alternative kit reconstitution methods, we recommend the NS/Tc method, since it may reduce the hand radiation dose.

Evaluation of various methods of 99Tcm-human immunoglobulin preparation in scintigraphic detection of infection.

Radiolabelled human immunoglobulin (HIG) scintigraphy has been recognized as a reliable modality for the localization and evaluation of pyogenic infection in humans. Four methods of labelling HIG with 99Tcm developed by the Institute of Nuclear Energy Research of Taiwan are: (1) using ascorbic acid (ASC) for direct labelling of HIG (ASC-HIG); (2) using diethylenetriamine pentaacetate (DTPA) as a bifunctional chelate (DTPA-HIG); (3) using 2-iminothiolane (IM) for modified protein (IM-HIG); (4) using the avidin-biotin system (AVI-BIO-HIG). Our study assessed these four preparations in the scintigraphic detection of infections. Staphylococcus aureus was injected intramuscularly into the left thighs of rabbits. Two days later, when active inflammation developed, 5 mCi 99Tcm-HIG was given intravenously; scintigraphy was performed at 1, 4 and 18 h. The accumulation of 99Tcm DTPA-HIG was the most prominent among the four preparations at the site of infection. It is concluded that 99Tcm labelling of HIG using DTPA as a bifunctional chelate may be the optimal labelling method for detecting infection.