SU-E-T-195: Experience in Implementing Intraoperative Radiation Therapy for Accelerated Partial Breast Irradiation Using Low-Energy X-Ray Source

PURPOSE

To present our preliminary experience and quality-assurance (QA) procedures in implementing intraoperative-radiation therapy (IORT) for accelerated-partial-breast irradiation (APBI) using the Axxent-system controller (Xoft Inc.) Methods: IORT was implemented in our institution utilizing a 50-keV x-ray source. APBI allows breast conserving in patients with early-stage-breast cancer by delivering radiation to the lumpectomy bed via an applicator balloon filled with water, to which a prescribed dose of 20 Gy was applied to its surface. In-situ anesthesiology, breast-surgery and radiation-oncology teams were required to achieve this procedure. Calibration of the source, including temperature and pressure corrections, was performed by the controller resulting in a calibration factor, which was manually introduced by a physicist into an in-house program providing the corrected dwell times. Evaluation of exposure measurements determined that personnel standing behind glass-rolling shields during irradiation were sufficient protection.

RESULTS

We have successfully treated four patients to date. Surgical times averaged about two hours, QA and setup of controller took about 30 minutes, while radiation-treatment times ranged 7.8-10.4 minutes. Exposure to personnel showed a negligible dose compared to background based on the in-vivo measurements. Our measurements have shown that placement of a shielding layer (FlexiShield) on top of the drape-protected breast reduced radiation exposure to in-room personnel. In one case, treatment was automatically stopped by the controller due to a sudden undetected cooling water flow; due to the pre-treatment training, treatment was successfully resumed within a minute after manual adjustment of the flow sensor.

CONCLUSIONS

Implementation of IORT to treat patients with APBI using low-energy x-ray source should follow the manufacturer's recommendations regarding to the acceptance and personnel training. Our experience indicates that two physicists are necessary at least at the implementation stage. Appropriate training to deal with potential problems is crucial before clinical treatment can be ready.

Microbial response to limited nutrients in shallow water immediately after the end-Permian mass extinction

Previous work indicates that a variety of microbes bloomed in the oceans after the end-Permian faunal mass extinction, but evidence is sporadically documented. Thus, the nature and geographic distribution of such microbes and their associations are unclear, addressed in this study using a series of biomarker groups. On the basis of microbial biomarker records of the 2-methylhopane index, evidence is presented for cyanobacterial blooms in both the western and eastern Tethys Sea and in both shallow and deep waters, after the mass extinction. The enhanced relative abundance of C(28) (expressed by the C(28) /C(29) ratio of) regular steranes suggests a bloom of prasinophyte algae occurred immediately after the end-Permian faunal extinction, comparable with those observed in some other mass extinctions in Phanerozoic. Significantly, cyanobacteria and prasinophyte algae show a synchronized onset of bloom in the shallow water Bulla section, north Italy, inferring for the first time their coupled response to the biotic crisis and the associated environmental conditions. However, in Meishan of Zhejiang Province in south China, the bloom declined earlier than in Bulla. The association of increased 2-methylhopane index with a negative shift in the nitrogen isotope composition infers a scenario of enhanced nitrogen fixation by cyanobacteria immediately after the faunal mass extinction. N(2) fixation by cyanobacteria is here interpreted to have provided prasinophyte algae with ammonium in nutrient-limited shallow waters, and thus caused their associated blooms.

Construction of tissue-engineered composite intervertebral disc and preliminary morphological and biochemical evaluation

The aim of this study was to construct tissue-engineered composite intervertebral disc (IVD) consisting of demineralized bone matrix gelatin (DBMG) and collagen II/hyaluronate/chondroitin-6-sulfate (CII/HyA-CS) scaffolds seeded with anulus fibrosus (AF) and nucleus pulposus (NP) cells, respectively. The cell-scaffold hybrids were implanted in the subcutaneous space of the dorsum of athymic mice and harvested at 4, 8, and 12 weeks. At each time point, the gross and histological morphology and biochemical properties were evaluated. Our results are as following: the gross morphology and histology of the composite resembled those of native IVD. Morphological studies revealed progressive tissue formation and junction integration between AF and NP regions. Biochemical composition detection indicated that the content of DNA, proteoglycan and hydroxyproline increased with time, and were similar to native tissue at 12 weeks. All these results demonstrated the feasibility of creating a tissue-engineered composite IVD with similar morphological and biochemical properties to the native tissue.

Photoemission electron microscopy using extreme ultraviolet attosecond pulse trains

We report the first experiments carried out on a new imaging setup, which combines the high spatial resolution of a photoemission electron microscope (PEEM) with the temporal resolution of extreme ultraviolet (XUV) attosecond pulse trains. The very short pulses were provided by high-harmonic generation and used to illuminate lithographic structures and Au nanoparticles, which, in turn, were imaged with a PEEM resolving features below 300 nm. We argue that the spatial resolution is limited by the lack of electron energy filtering in this particular demonstration experiment. Problems with extensive space charge effects, which can occur due to the low probe pulse repetition rate and extremely short duration, are solved by reducing peak intensity while maintaining a sufficient average intensity to allow imaging. Finally, a powerful femtosecond infrared (IR) beam was combined with the XUV beam in a pump-probe setup where delays could be varied from subfemtoseconds to picoseconds. The IR pump beam could induce multiphoton electron emission in resonant features on the surface. The interaction between the electrons emitted by the pump and probe pulses could be observed.

Tolerant T cells inhibit natural killer cells function in antigen-presenting cells in an independent fashion

Understanding the relationships among immune cells in the setting of immunologic tolerance is imperative to maintain organ and tissue transplants. T cells and natural killer (NK) cells are responsible for both immune tolerance and immune rejection; however, there is only limited knowledge about the relevance of T and NK cells in tolerance. To address this issue, we explored the possible actions of tolerant T cells on NK cells by the means of mixed lymphocyte co-cultures and NK cytotoxicity assays. We showed that tolerant T cell-induced blockade of the co-stimulatory pathway significantly inhibited NK cell function in vitro regarding antigen-presenting cells. This action was cell-cell-contact dependent. We argue that tolerant T cells and NK cells impart synergistic cooperation to maintain transplant tolerance.

A closer look at the number of lymph nodes examined in colorectal cancer: A VAMC experience

e15117

Background: Retrieval of 12 lymph nodes (LN) is a current benchmark in colorectal cancer (CRC) resections according to the National Quality Forum (NQF). Series of multiple institutions contain variability in surgical and pathologic techniques for lymph node retrieval. To ensure consistency in retrieving lymph nodes for satisfactory staging, we present a 12 year experience by a single surgeon and single pathology lab at one VAMC on 157 patients (mean age 67) undergoing CRC resection. Furthermore, the use of chemotherapy for Stage II patients <12 LN retrieved is controversial and yields only a small survival benefit. Methods: The records of 157 patients from one surgeon's case log from 1994–2007 were reviewed. Strict guidelines were applied to remove the same distribution of pericolonic fat. The lab followed a two step approach to LN dissection: Step 1 search for grossly identifiable LN; Step 2 overnight Carnoy's immersion to find smaller LN. Statview and SAS software analyzed 1)Overall survival (OS) and association with finding >12LN; 2)Number of LN identified and impact on AJCC tumor stage (TS) and overall survival; 3)Number of LN and WHO tumor grade (TG) with OS; 4)The impact of number of positive LN on OS. Results: Our mean LN found (14.75) is higher than the 12 recommended by the NQF and is not significantly associated with OS regardless of AJCC TS(p=0.06). The mean LN per TS was I=13.4(N=41)/II=16.3(N=56)/ III=14.3(N=38)/IV 14.2(N=22). Number of LN identified was not statistically significant in predicting TS(p=0.42) or OS(p=0.24). WHO TG is significantly associated to decreased OS, but only in AJCC TS II/III/IV and not stage I (Ip>0.05/IIp=0.008/ IIIp=0.01/IVp=0.025). Higher number of positive LN was associated with lower OS (per each +LN, survival decreases by 0.15 months p=0.001) Conclusions: Contrary to multicenter studies, total number of LN identified does not impact AJCC TS or OS. Higher WHO TG and higher number of positive LN is associated with worse OS. This suggests that the tumor biology is more indicative of OS rather than host response (reactive lymphoid tissue) to the tumor. Stage II patients <12 LN may not be ‘high risk’ and adjuvant chemotherapy based on this factor alone should be reconsidered. Further studies would be warranted.

No significant financial relationships to disclose.

A new multifunctional platform based on high aspect ratio interdigitated NEMS structures

A multifunctional NEMS platform based on a mass-producible, surface relief grating has been developed and fabricated directly in polymer materials. The pattern consists of high aspect ratio interdigitated nanometer-sized pairs of walls and can be produced in a low-complexity one-step patterning process with nanoimprint lithography. In this paper, we demonstrate the usefulness of the platform primarily by showing an application as a high-sensitivity mass sensor in air. The sensors, which are based on the high frequency resonant response of around 200 MHz, show a mass responsivity of the order of 0.1 Hz/zg per wall at room temperature and in ambient air. Their ability to selectively adsorb airborne target molecules, such as thiols, is also demonstrated. We also show that the same device can function as a varactor for electronic circuits based on its large tunable capacitive range.

Modulation of LPS-induced pulmonary neutrophil infiltration and cytokine production by the selective PPARbeta/delta ligand GW0742

OBJECTIVE

To define the anti-inflammatory effects of PPARbeta/delta activation by use of the selective PPARbeta/delta ligand (GW0742) in a model of lipopolysaccharide (LPS)-induced pulmonary inflammation.

METHODS

Male BALB/c mice were pretreated for three days with the PPARbeta/delta agonist, GW0742, prior to induction of LPS-mediated pulmonary inflammation. Bronchial alveolar lavage fluid (BALF) was analyzed for inflammatory cell influx and for levels of pro-inflammatory mediators. BALF-derived inflammatory cells were also collected for mRNA analysis.

RESULTS

Pretreatment with GW0742 resulted in a significant decrease in leukocyte recruitment into the pulmonary space. Protein and mRNA levels of the pro-inflammatory cytokines IL-6, IL-1beta and TNFalpha in BALF were found to be significantly decreased in GW0742-treated animals (30 mg/kg). A significant decrease in granulocyte macrophage-colony stimulating factor (GM-CSF), a major regulator of neutrophil chemotaxis (via its downstream actions on TNFalpha and other cytokines/chemokines), activation and survival, was also noted in the BALF levels of GW0742-treated animals.

CONCLUSIONS

The present study demonstrates that activation of PPARbeta/delta attenuates the degree of inflammation in a model of LPS-induced pulmonary inflammation and may therefore represent a novel therapeutic approach for the treatment of inflammation-mediated pathologies.

An efficient solvent-free synthesis of benzoxanthenes catalyzed by BSA or O-TSA

A series of 14-alkyl and aryl-14H-dibenzo[a.j]xanthenes have been synthesized with high yields through a one-pot condensation of beta-naphthol with alkyl or aryl aldehydes in the presence of BSA or o-TSA in a solvent-free medium.

ESDN is a marker of vascular remodeling and regulator of cell proliferation in graft arteriosclerosis

Vascular remodeling is a common feature of many vasculopathies, including graft arteriosclerosis (GA). We investigated whether endothelial and smooth muscle cell-derived neuropilin-like protein (ESDN) is a marker of vascular remodeling in GA. Immunostaining of human coronary arteries demonstrated high levels of ESDN in GA, but not in normal arteries. In a model of GA, where a segment of human coronary is transplanted into a severe combined immunodeficient mouse, followed by allogeneic human peripheral blood mononuclear cell (PBMC) reconstitution, ESDN was minimally expressed in transplanted human arteries in the absence of reconstitution. By 2 weeks following PBMC reconstitution, at a time corresponding to maximal vascular cell proliferation, high levels of ESDN were detected in the transplanted arteries. Similarly, injury-induced vascular remodeling in apoE(-/-) mice was associated with early and transient ESDN upregulation, in parallel with cell proliferation. In vascular smooth muscle cell (VSMC) cultures, ESDN expression was significantly higher in proliferating, as compared to growth-arrested cells. ESDN overexpression in VSMC led to a decline in growth curves, while ESDN knock down had the opposite effect. We conclude that ESDN is a marker of vascular remodeling and regulator of VSMC proliferation. ESDN may serve as a therapeutic or diagnostic target for GA.

Effects of Ischemia-Reperfusion Injury on Apolipoprotein M Expression in the Liver

The present study investigated the expression pattern of apolipoprotein M (apoM) mRNA in a rat model of hepatic ischemia-reperfusion injury (IRI). Animals were ischemic for 1 hour followed by various reperfusion times. As expected, serum alanine aminotransferase levels were significantly increased under IRI, which indicated the severity of liver injury. Hepatic mRNA levels of HSP70, which is the most common characterized protein within the family of heat-shock proteins (HSP), were significantly increased after 0.5 to 3 hours of IRI. Plasma C-reactive protein, high-density lipoprotein-cholesterol, and lipoprotein (a) levels were significantly increased after 1-hour ischemia followed by 0.5 to 3 hours of reperfusion. Interestingly, similar to HSP70, apoM mRNA levels in the liver were gradually increased after 0.5 to 3 hours of IRI, whereas it returned to a lower level after 6 or 24 hours of IRI, which indicated that hepatic apoM expression was significantly influenced by the acute phase of IRI. However, plasma apoM levels were not increased in parallel, even slightly decreasing after 0.5 or 1 hour of IRI. We concluded that apoM mRNA expression pattern, like HSP70, in the liver showed rapid, significant changes during hepatic local IRI.

Short-term administration of ACTH improves plasma lipid profile and renal function in kidney transplant patients

The present study investigated effects of short-term administration of adrenocorticotrophic hormone (ACTH) on blood lipid profile and renal function in kidney transplant patients. Six patients who had kidney transplantations 2 to 10 years earlier received ACTH intramuscularly (1 mg/d) for 4 days. We analyzed serum levels of lipids, lipoproteins, apolipoproteins, blood creatinine, and other parameters. Short-term ACTH treatment significantly decreased serum apolipoprotein B and apolipoprotein AI, whereas it significantly increased plasma high-density lipoproteins (HDL). Interestingly, creatinine level moderately decreased and creatinine clearances moderately increased among five of six patients. Hepatic function and serum concentration of cyclosporine did not change. There were no serious side effects during ACTH treatment. It was concluded that ACTH treatment had beneficial effects on serum lipoprotein profile, potentially improving renal function in kidney transplant patients. Further observations are needed to confirm these effects.

Metformin-diet ameliorates coronary heart disease risk factors and facilitates resumption of regular menses in adolescents with polycystic ovary syndrome

BACKGROUND

In 35 adolescent females (17 +/- 2 years) with polycystic ovary syndrome (PCOS), median body mass index (BMI) 30.8 kg/m2, we assessed effeicacy of metformin-diet for 1 year for reduction of weight, insulin, HOMA insulin resistance (IR), cholesterol, triglycerides, and resumption of regular menses.

METHODS

Calories (26% protein, 44% carbohydrate) were targeted to 1,500-1,800/day if BMI was <25 or to 1,200-1,500/day if BMI was > or = 25, along with 2,550 mg metformin.

RESULTS

Median weight fell from 82.7 to 79.1 kg (p = 0.009), insulin 16.7 to 13.3 microU/ml (p <0.0001), HOMA IR 3.41 to 2.74 (p = 0.0004), total cholesterol 164 to 151 mg/dl (p = 0.002), and triglyceride 103 to 85 mg/dl (p = 0.006). The percentage of cycles with normal menses rose from a pre-treatment mean of 22% to 74%, p < 0.0001.

CONCLUSIONS

In adolescents with PCOS, metformin-diet reduces weight, insulin, IR, cholesterol, and triglycerides, and facilitates resumption of regular menses.

The regulation of cell migration by PTEN

In vertebrates, the tumour suppressor PTEN (phosphatase and tensin homologue deleted on chromosome 10) regulates many cellular processes through its PtdIns(3,4,5)P3 lipid phosphatase activity, antagonizing PI3K (phosphoinositide 3-kinase) signalling. Given the important role of PI3Ks in the regulation of directed cell migration and the role of PTEN as an inhibitor of migration, it is somewhat surprising that data now indicate that PTEN is able to regulate cell migration independent of its lipid phosphatase activity. Here, we discuss the role of PTEN in the regulation of cell migration.

Desorption/Ionization on Silicon Nanowires

Dense arrays of single-crystal silicon nanowires (SiNWs) have been used as a platform for laser desorption/ionization mass spectrometry of small molecules, peptides, protein digests, and endogenous and xenobiotic metabolites in biofluids. Sensitivity down to the attomole level has been achieved on the nanowire surfaces by optimizing laser energy, surface chemistry, nanowire diameter, length, and growth orientation. An interesting feature of the nanowire surface is that it requires lower laser energy as compared to porous silicon and MALDI to desorb/ionize small molecules, therefore reducing background ion interference. Taking advantage of their high surface area and fluid wicking capabilities, SiNWs were used to perform chromatographic separation followed by mass analysis of the separated molecules providing a unique platform that can integrate separation and mass spectrometric detection on a single surface.

Prospective study of relationship between cytomegalovirus pneumonia and viral load in renal transplant recipients

The present study prospectively examined the relationship between cytomegalovirus interstitial pneumonia (CMV-IP) and viral load among 56 renal transplant recipients. We sought to identify the cutoff of viral load to predict CMV-IP. Blood samples were obtained weekly within the first 2 months and every second week during 2 to 6 months after kidney transplantations. A commercial real-time polymerase chain reaction (PCR)-method was applied to quantify CMV-DNA in plasma or in leukocytes. Among 54 renal transplant recipients who were analyzed for CMV-DNA in the blood (96.4%), 8 experienced CMV-IP (14.3%) and 2 died (3.6%). After kidney transplantation, CMV-DNA loads were near 0 in plasma before the week 4 and before the week 3 in leukocytes among both groups. From week 5 (week 4, in leukocytes), plasma CMV-DNA loads in the CMV-IP group increased, the peak value reached at week 8 in plasma and the week 9 in leukocytes. Whereas, the CMV-DNA loads both in plasma and in leukocytes in the non-CMV-IP group fluctuated at lower levels, those in plasma were significantly different between the 2 groups at the weeks 5, 7, and 9. For CMV-DNA in leukocytes, there were significant differences between 2 groups from week 6 to week 11. The present study demonstrated that dynamic determination of CMV-DNA may predict the occurrence of CMV-IP. Viral loads over 10(4) copies/mL plasma continuing for 3 weeks may serve as a cutoff to predict CMV-IP.

Reverse transcriptase polymerase chain reaction (RT-PCR) detection of HLP gene expression in Candida glabrata and its possible role in in vitro haemolysin production

Although haemolysins are known to be putative virulence factors contributing to pathogenicity in Candida species, the haemolytic activity of Candida glabrata and its genetic expression is ill understood at present. Thus, we studied a total of 34 Candida glabrata isolates for their in vitro haemolytic activity using a previously described plate assay system. The mRNA expression of HLP, a putative haemolysin gene, of these isolates was also evaluated using a semi-quantitative, non-competitive RT-PCR assay. All 34 C. glabrata isolates exhibited both partial (alpha) and complete (beta) haemolytic activity to varying degrees. In parallel with the haemolytic activity, all isolates were also positive for HLP mRNA expression. The expression levels of HLP mRNA (as relative units) ranged from 1.01 to 1.82, with a mean value of 1.32. On regression analysis of latter values and the haemolytic activity (in terms of the dimension of the haemolytic zone in the plate assay) of the C. glabrata isolates a highly significant positive correlation was noted (r=0.759, p<0.0001). Taken together, our data illustrate not only the phenotypic characteristics of haemolysin(s) and HLP expression of a battery of C. glabrata clinical isolates, but also, for the first time, evidence for a role of HLP in haemolysis.

Glass fibre-reinforced composite laced with chlorhexidine digluconate and yeast adhesion

The aim of this study was to lace dental glass fibre reinforced composite (FRC) prepreg with chlorhexidine digluconate and to examine the adherence of common oral fungal pathogen Candida albicans to FRC made of the prepreg. Four different test and control material groups each comprising 16 test specimens ((5.0 x 5.0 x 0.8) mm3) each were used as substrates for C. albicans adherence. A porous polymer pre-impregnated woven glass fibre prepreg was laced with solution of chlorhexidine gluconate and it was used with autopolymerized denture base polymer to fabricate FRC test specimens. Control group (Group 1) consisted of FRC test specimens stored in water. In Group 2, the test specimens were stored in 10% chlorhexidine digluconate solution for 24 h. Group 3 consisted of specimens fabricated using such fibre reinforcements which were pre-soaked in 20% chlorhexidine digluconate and dried before preparation with denture base resin, and followed by storage of the specimens in water. Group 4 was similar to Group 3 but instead of water storage the specimens were immersed in 10% chlorhexidine digluconate for 24 h. For the candidal adhesion assay the test and control specimens were incubated in standardized suspensions of four different strains of C. albicans, rinsed and prepared for light-microscopy. The mean number of adherent cells in each group was counted microscopically and analysed statistically. There were significantly (P < 0.05) more adherent C. albicans cells found in Group 1 than in the other three groups which did not differ significantly from each other. The lowest numbers of adherent cells were found in Group 3. Pretreating the porous polymer pre-impregnated glass fibre reinforcement with chlorhexidine digluconate result in reduction in the number of adherent yeast cells on the surface FRC material.

Laser-based mid-infrared reflectance imaging of biological tissues

Mid-infrared (MIR) (3-12 um) spectral imaging is a power analytical tool, but difficult in the back-reflectance mode for in-vivo diagnostics. Feasibility of MIR back-reflectance imaging is demonstrated using MIR semiconductor lasers. Transmittance through 500-microm thick films of water and blood showed a capability to resolve more than 6-OD signal dynamic range. Reflectance scanning imaging through a 150-microm thick film of blood showed negligible scattering effect, indicating the feasibility of optical coherent imaging. The result of coherent imaging of a plant leaf shows a MIR sub-surface image that would not be visible in white light. With two wavelengths, a similar result for a chicken skin subcutaneous tissue at different focal depths was obtained, showing blood vessels beneath a lipid layer. These results suggest that advanced multilaser wavelength systems in the fingerprint spectral region can be a useful tool for in-vivo spectral imaging in biomedical research and diagnostic applications.

Actinomyces spp. in supragingival plaque of ethnic Chinese preschool children with and without active dental caries

Very limited molecular epidemiological data are available on the role of Actinomyces spp. in the pathogenesis of caries in the primary dentition. Therefore, we investigated their distribution in supragingival plaque of ethnic Chinese preschool children from Singapore and Hong Kong, either with or without active caries. Plaque samples were taken from intact interproximal enamel areas using dental floss. Bacterial genomic DNA of each sample was extracted and variable regions of 16S ribosomal DNA amplified and labelled with digoxigenin. Oligonucleotide probes specific for Actinomyces bovis, Actinomyces gerencseriae, Actinomyces israelii, Actinomyces meyeri, Actinomyces odontolyticus, catalase-negative Actinomyces naeslundii (genospecies 1 and 2) and catalase-positive Actinomyces naeslundii genospecies 2 (previously Actinomyces viscosus serotype II) were used to detect these species using Southern hybridization with a Minislot and Miniblotter system. A. odontolyticus, A. gerencseriae and A. meyeri were detected with similar frequency in both Singapore and Hong Kong samples or in those with and without active caries. However, the prevalence of A. naeslundii was significantly different in the two locales (p<0.05). A. odontolyticus (88.7%), A. gerencseriae (56.6%) and A. naeslundii (50.9%) were detected in a majority of the samples and the positive hybridization signals of A. gerencseriae in the caries-active group were stronger than from the caries-free group. A. bovis and A. israelii were undetectable in any of the samples. These data imply that A. odontolyticus, A. naeslundii and A. gerencseriae may play an important role in supragingival plaque formation on primary teeth in ethnic Chinese, with others such as A. meyeri contributing.

Development of novel oligonucleotide probes for seven Actinomyces species and their utility in supragingival plaque analysis

OBJECTIVE

The traditional, biochemical and enzymatic methods of identifying Actinomyces species are frequently confounded by the similar phenotypic characteristics shared by the different members of this genus. Therefore, we developed novel species-specific oligonucleotide probes to accurately speciate seven pathogenic Actinomyces species, namely, Actinomyces bovis, A. gerencseriae, A. israelii, A. meyeri, A. naeslundii, A. odontolyticus and A. viscosus.

METHODS

A pair of universal primers and seven 15- to 19-base oligonucleotide probes with a tail of 20 thymidines on the 5' end were developed. The variable regions of 16S ribosomal DNA of 36 strains of Actinomyces belonging to the above species were amplified and labeled with digoxigenin, and an oligonucleotide-DNA hybridization assay was performed to examine the specificity and sensitivity of these probes.

RESULTS

All seven, newly developed probes were specific and sensitive, and accurately detected 36 reference and wild type strains belonging to Actinomyces species, without cross-reactions. The probe for A. naeslundii detected all strains belonging to the genospecies 1 (12 strains) and catalase-negative genospecies 2 (four strains); it failed to detect catalase-positive A. naeslundii genospecies 2 (previous A. viscosus serotype II) (two strains). However, the latter strains of catalase-positive A. naeslundii genospecies 2 were correctly detected by the probe developed for A. viscosus. The new probes were then field tested using supragingival plaque samples from 28 healthy preschool children. Whilst A. odontolyticus was detected in almost all samples (96.4%), A. gerencseriae, A. meyeri, catalase-negative A. naeslundii and catalase-positive A. naeslundii genospecies 2 were detected in < 50% samples.

CONCLUSION

We conclude that the developed oligonucleotide probes, complementary to the variable regions of 16S rDNA, would be of potential value for differentiating Actinomyces spp. in clinical samples from the oral cavity and other ecosystems where such species may abound.

Candida glabrata, an emerging fungal pathogen, exhibits superior relative cell surface hydrophobicity and adhesion to denture acrylic surfaces compared with Candida albicans

Oral candidosis is a common opportunistic infection in debilitated individuals and Candida glabrata is the second most frequently isolated species from this condition, after Candida albicans. Candidal adherence to various biological or non-biological surfaces is considered a prerequisite for colonization, and pathogenesis of candidal infections, and their relative cell surface hydrophobicity (CSH) is likely to be a possible contributory force involved in this process. Whereas a large body of data on the latter features of C. albicans is available, there is surprisingly little information on C. glabrata. As a comprehensive database on the relative adhesion and CSH of Candida spp. is instructive and useful, we investigated in vitro the latter attributes of 34 oral isolates of C. glabrata and 15 isolates of C albicans. There were remarkable intraspecies differences in both the CSH and the adhesive ability of C. glabrata strains (p < 0.001). Compared with C. albicans, C glabrata demonstrated a four-fold greater CSH value (30.63 +/- 11.20% vs 7.23+/-3.56%, p < 0.0001) and a two-fold greater tendency to adhere to denture acrylic surfaces (75.18 +/- 39.96 vs 30.36+/-9.21, p < 0.0001). A significant positive correlation between CSH and adhesion was also noted for both C. glabrata (r=0.674, p < 0.0001) and C. albicans ( r = 0.636, p < 0.05). When the effect of different incubation conditions on the relative CSH and adherence of C. glabrata was examined, CSH and the adherence to acrylic surfaces of four of six C. glabrata isolates were significantly affected by a reduction of the culture temperature (from 37 degrees C to 25 degrees C). A positive relationship also emerged when the temperature-induced variations in the adherence values were correlated with their relative CSH. These data provide hitherto unavailable archival information on important pathogenic attributes of the two most common oral Candida species that may help explain their predominance in this milieu.

[The measurement of multifocal electroretinography]

PURPOSE

Discussing the testing procedure of multifocal electroretinography(ERG).

METHODS

The testing procedure of 131 multifocal ERG records was reviewed.

RESULTS

Some variable factors existed in the measurement of multifocal ERG. These factors included the subject's co-operation, the mounting of electrode, the fixation of tested eye and adjustment of focus. The good records of multifocal ERG depend upon the skill of the operator.

CONCLUSION

The testing procedure of multifocal ERG must be standardized so as to ensure the reliability and repeatability of the results.

[The preliminary report of cervical cancer treated with californium-252 neutron after loading intracavitary radiotherapy]

OBJECTIVE

To observe the therapeutic effectiveness and complications of californium-252 (252Cf) brachytherapy in cervical cancer.

METHODS

Fifty one cases of cervical cancer were diagnosed according to the standard of the International Federation of Gynecology and Obstetrics (FIGO), II a:8 cases, II b:31 cases, III a:8 cases, III b:4 cases. Treatment schedule: 252Cf after loading brachytherapy, 10-12 Gy/fraction/week, the total dose of reference point A was 36-40 Gy in three to four implant sessions. In the second day after 252Cf therapy, the whole pelvis was treated with 6 MV X-ray external beam radiotherapy, 200 cGy per fraction, 4 times per week. The total dose of external beam radiotherapy was 40 to 50 Gy (the middle of pelvis was blocked at width of 4 cm after 20-30 Gy), then the total dose of reference point B was 50-55 Gy;the total treatment time was 5-6 weeks.

RESULTS

The average time of complete tumor regression was 25 days, the local control rate of 2 year was 100%, the total 2 year survival rate was 92%, i.e., II a: 8/8 cases, II b: 30/31 cases (97%), III a: 6/8 cases, III b: 3/4 cases; the late radiation complications of bladder and rectum was 2% respectively during these 2 years.

CONCLUSIONS

It is concluded that combined 252 Cf brachytherapy and high energy X-ray external beam radiotherapy may be safe and effective in the management of cervical cancer. 252Cf has advantages of high local control rate; rapidly regression of bulky tumors and low-grade radiation complications.

Generation of three selenium-containing catalytic antibodies with high catalytic efficiency using a novel hapten design method

A novel strategy for design of haptens that were used to produce catalytic antibodies was developed and three monoclonal antibodies, 3G5, 2F3, and 5C9, were generated using this strategy. These monoclonal antibodies were converted into selenium-containing abzymes by chemically modifying the hydroxyl group of serines followed by sodium hydrogen selenide displacement. These selenium-containing abzymes exhibited remarkable glutathione peroxidase activity, which surpasses the activity of some native glutathione peroxidases. The activities of the selenium-containing abzymes Se-3G5, Se-2F3, and Se-5C9 which catalyzed reduction of hydroperoxides by glutathione were 2.23, 4.20, and 3.79 times that of rabbit liver glutathione peroxidase, respectively. Detailed steady-state kinetics study on Se-2F3 was carried out and the value of k(cat)/K(m) (H(2)O(2)) was found to be 2.11 x 10(7) M(-1) min(-1) which was supposed to be one of the highest among the known catalytic antibodies. The data of association constants and glutathione peroxidase activities of these catalytic antibodies and the steady-state kinetics of Se-2F3 showed that the method might be a remarkably efficient one for generating catalytic antibodies with glutathione peroxidase activity.

A novel dicyclodextrinyl ditelluride compound with antioxidant activity

Reactive oxygen species (ROS) primarily arise from products of normal metabolic activities and are thought to be the etiology of many diseases. A novel dicyclodextrinyl ditelluride (2-TeCD) compound was designed to be a functional mimic of the glutathione peroxidase that normally removes ROS. 2-TeCD exhibited highly catalytic efficiency and good water solubility. Antioxidant activity was studied by using ferrous sulfate/ascorbate-induced mitochondria damage model system. 2-TeCD protected the mitochondria against oxidative damage in a dose-dependent manner and exhibited also great antioxidant ability in comparison with 2-phenyl-1,2-benziososelenazol-3(2H)-one. The mimic may result in better clinical therapies for the treatment of ROS-mediated diseases.

Cloning and expression of a single-chain catalytic antibody that acts as a glutathione peroxidase mimic with high catalytic efficiency

Glutathione peroxidase (GPX) has a powerful role in scavenging reactive oxygen species. In previous papers we have developed a new strategy for generating abzymes: the monoclonal antibody with a substrate-binding site is first prepared, then a catalytic group is incorporated into the monoclonal antibody's binding site by using chemical mutation [Luo, Zhu, Ding, Gao, Sun, Liu, Yang and Shen (1994) Biochem. Biophys. Res. Commun. 198, 1240-1247; Ding, Liu, Zhu, Luo, Zhao and Ni (1998) Biochem. J. 332, 251-255]. Since then we have established a series of catalytic antibodies capable of catalysing the decomposition of hydroperoxides by GSH. The monoclonal antibody 2F3 was raised against GSH-S-2,4-dinitrophenyl t-butyl ester and exhibited high catalytic efficiency, exceeding that of rabbit liver GPX, after chemical mutation. To produce pharmaceutical proteins and to study the reason why it exhibits high catalytic efficiency, we sequenced, cloned and expressed the variable regions of 2F3 antibody as a single-chain Fv fragment (2F3-scFv) in different bacterial strains. The amounts of 2F3-scFv proteins expressed from JM109 (DE3), BL21 (DE3), and BL21 (coden plus) were 5-10%, 15-20% and 25-30% of total bacterial proteins respectively. The 2F3-scFv was expressed as inclusion bodies, purified in the presence of 8 M urea by Co(2+)-immobilized metal-affinity chromatography (IMAC) and renatured to the active form in vitro by gel filtration. The binding constants of the active 2F3-scFv for GSH and GSSG were 2.46 x 10(5) M(-1) and 1.03 x 10(5) M(-1) respectively, which were less by one order of magnitude than that of the intact 2F3 antibody. The active 2F3-scFv was converted into selenium-containing 2F3-scFv (Se-2F3-scFv) by chemical modification of the reactive serine; the GPX activity of the Se-2F3-scFv was 3394 units/micromol, which approaches the activity of rabbit liver GPX.

Identification and localization of five CYP2Cs in murine extrahepatic tissues and their metabolism of arachidonic acid to regio- and stereoselective products

The CYP2C subfamily has been extensively studied in humans with respect to the metabolism of clinically important drugs, and polymorphisms have been identified in these enzymes. In the present study, a murine model was used to determine the possible physiological functions and extrahepatic distribution of CYP2Cs. Using the reverse transcription-polymerase chain reaction (RT-PCR), Western blotting, and immununohistochemistry, this report demonstrates that the mouse CYP2Cs are extensively distributed in extrahepatic tissues and localized to heart muscle, lung Clara and ciliated cells, kidney collecting ducts, the X-zone of female adrenals, reproductive organs, white blood cells, and eyes (in the optic nerve, rods, and cones). RT-PCR, subcloning, and sequencing of the products indicate that each CYP2C has a unique tissue distribution. Four cDNA fragments representing potentially new CYP2Cs were identified, each with its own organ-specific pattern of expression. Using a bacterial cDNA expression system, we found that recombinant proteins for each of the five full-length murine CYP2Cs metabolize arachidonic acid to different regio- and stereospecific products, including epoxyeicosatrienoic acids and hydroxyeicosatetraenoic acids. Regio- and stereospecific metabolites of arachidonic acid have been reported to affect important physiological functions such as inflammation, neutrophil activation, ion transport, cellular proliferation, and vascular tone. Our results suggest that the presence of CYP2C enzymes in heart muscle, aorta, kidney, lung, adrenals, eyes, and reproductive organs could regulate important physiological and/or pathological processes in these tissues.