Selection and evaluation of potential reference genes for gene expression analysis in the brown planthopper, Nilaparvata lugens (Hemiptera: Delphacidae) using reverse-transcription quantitative PCR

The brown planthopper (BPH), Nilaparvata lugens (Hemiptera, Delphacidae), is one of the most important rice pests. Abundant genetic studies on BPH have been conducted using reverse-transcription quantitative real-time PCR (qRT-PCR). Using qRT-PCR, the expression levels of target genes are calculated on the basis of endogenous controls. These genes need to be appropriately selected by experimentally assessing whether they are stably expressed under different conditions. However, such studies on potential reference genes in N. lugens are lacking. In this paper, we presented a systematic exploration of eight candidate reference genes in N. lugens, namely, actin 1 (ACT), muscle actin (MACT), ribosomal protein S11 (RPS11), ribosomal protein S15e (RPS15), alpha 2-tubulin (TUB), elongation factor 1 delta (EF), 18S ribosomal RNA (18S), and arginine kinase (AK) and used four alternative methods (BestKeeper, geNorm, NormFinder, and the delta Ct method) to evaluate the suitability of these genes as endogenous controls. We examined their expression levels among different experimental factors (developmental stage, body part, geographic population, temperature variation, pesticide exposure, diet change, and starvation) following the MIQE (Minimum Information for publication of Quantitative real time PCR Experiments) guidelines. Based on the results of RefFinder, which integrates four currently available major software programs to compare and rank the tested candidate reference genes, RPS15, RPS11, and TUB were found to be the most suitable reference genes in different developmental stages, body parts, and geographic populations, respectively. RPS15 was the most suitable gene under different temperature and diet conditions, while RPS11 was the most suitable gene under different pesticide exposure and starvation conditions. This work sheds light on establishing a standardized qRT-PCR procedure in N. lugens, and serves as a starting point for screening for reference genes for expression studies of related insects.

Selection and evaluation of reference genes for expression analysis using qRT-PCR in the beet armyworm Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae)

Quantitative real-time PCR (qRT-PCR) is a reliable and reproducible technique for measuring and evaluating changes in gene expression. The most common method for analyzing qRT-PCR data is to normalize mRNA levels of target genes to internal reference genes. Evaluating and selecting stable reference genes on a case-by-case basis is critical. The present study aimed to facilitate gene expression studies by identifying the most suitable reference genes for normalization of mRNA expression in qRT-PCR analysis of the beet armyworm Spodoptera exigua (Lepidoptera: Noctuidae). For this purpose, three software tools (geNorm, NormFinder and BestKeeper) were used to investigate 10 candidate reference genes in nine developmental stages and five different tissues (epidermis, head, midgut, fat body and hemolymph) in three larval physiological stages (molting, feeding and wandering stages) of, S. exigua. With the exception of 18S ribosomal RNA (18S), all other candidate genes evaluated, β-actin1(ACT1), β-actin2 (ACT2), elongation factor1(EF1), elongation factor 2 (EF2), Glyceralde hyde-3-phosphate dehydrogenase (GAPDH), ribosomal protein L10 (L10), ribosomal protein L17A (L17A), superoxide dismutase (SOD), α-tubulin (TUB),proved to be acceptable reference genes. However, their suitability partly differed between physiological stages and different tissues. L10, EF2 and L17A ranked highest in all tissue sample sets. SOD, ACT2, GAPDH, EF1 and ACT1 were stably expressed in all developmental stage sample sets; ACT2, ACT1 and L10 for larvae sample sets; GAPDH, ACT1 and ACT2 for pupae and adults; SOD and L17A for males; and EF2 and SOD for females. The expression stability of genes varied in different conditions. The findings provided here demonstrated, with a few exceptions, the suitability of most of the 10 reference genes tested in tissues and life developmental stages. Overall, this study emphasizes the importance of validating reference genes for qRT-PCR analysis in S. exigua.

The cardiovascular effects of glucagon-like peptide-1 receptor agonists: a trial sequential analysis of randomized controlled trials

WHAT IS KNOWN AND OBJECTIVE

Glucagon-like peptide-1 (GLP-1) receptor agonists are a new class of antidiabetic drugs. Their wider use for the treatment of patients with type 2 diabetes mellitus has led to concerns about its cardiovascular effects. However, the robustness of data leading to those concerns is unclear. The purpose of this study is to systematically assess the robustness of the available evidence on the adverse cardiovascular effects of GLP-1 receptor agonists in patients with type 2 diabetes.

METHODS

The Cochrane library, MEDLINE, EMBASE and www.clinicaltrials.gov were searched from inception through to 25 January 2013. Randomized controlled trials (RCTs) were selected if they compared GLP-1 receptor agonists with placebo or other drugs with a duration ≥12 weeks. Mantel-Haenszel odds ratio (MH-OR) of cardiovascular events with 95% confidence interval (CI) was estimated using a random effects model. Trial sequential analysis based on required information size with an assumption of plausible reductions in relative risk in the low-bias trials, 5% risk of a type I error and 20% risk of a type II error was used to explore the robustness of available evidence.

RESULTS

Fifty-eight trials were included in the analysis (10 466 patients receiving GLP-1 receptor agonists and 7138 patients receiving comparators, respectively). Overall, the OR for cardiovascular events with GLP-1 receptor agonists was 0·52 (95% CI: 0·27-0·99) compared with placebo and 0·84 (95% CI: 0·52-1·36) with active controls. Trial sequential analyses showed that the actual accumulated sample size was only 11% (7445 of 65 212) and 13% (10 157 of 79 198) of the required information size for placebo-controlled trials and active-controlled trials, respectively. These results indicate that there is still insufficient evidence on cardiovascular events.

WHAT IS NEW AND CONCLUSION

GLP-1 receptor agonists do not seem to show any increased risk of cardiovascular events However, the available data from RCTs remain insufficient to confirm an absence of detrimental effect. More long-term trials and population-based studies are required to provide the necessary reassurance on the cardiovascular safety of GLP-1 receptor agonists.

Developmental regulation and antifungal activity of a growth-blocking peptide from the beet armyworm Spodoptera exigua

Insect cytokine growth-blocking peptides (GBPs) are involved in growth regulation and the innate immune response. However, the microbial binding and antimicrobial activities of GBPs remain unclear. Here, we investigate the developmental role and antifungal activity of a GBP from the beet armyworm Spodoptera exigua (SeGBP). Sequence analysis predicted that mature SeGBP consists of 24 amino acid residues, including 2 cysteine residues. During S. exigua development, SeGBP is constitutively expressed in the fat body during the larval and adult stages but not in pupae. SeGBP expression is up-regulated by 20-hydroxyecdysone and down-regulated by juvenile hormone analog. Recombinant SeGBP purified from baculovirus-infected insect cells retards the growth of S. exigua larvae. Additionally, SeGBP expression is acutely induced in the fat body after injection with Escherichia coli, Bacillus thuringiensis, or Beauveria bassiana. Recombinant SeGBP can bind to B. bassiana but not to E. coli or B. thuringiensis. Consistent with these findings, SeGBP shows antifungal activity against B. bassiana. Therefore, these results provide insight into the role of SeGBP during the innate immune response following microbial infection, and furthermore, they suggest a novel function for SeGBP as a direct antifungal agent against entomopathogenic fungi, such as B. bassiana.

A spider (Araneus ventricosus) chymotrypsin inhibitor that acts as an elastase inhibitor and a microbial serine protease inhibitor

Spider-derived Kunitz-type serine protease inhibitors have been shown to exhibit plasmin and elastase inhibition activity and potassium channel blocking activity, but thus far, no additional roles for spider-derived chymotrypsin inhibitors have been elucidated. In this study, a spider (Araneus ventricosus) chymotrypsin inhibitor (AvCI) that acts as an elastase inhibitor and a microbial serine protease inhibitor was identified. AvCI is a 70-amino acid mature peptide that displays eight conserved cysteine residues and a P1 lysine residue. Recombinant AvCI expressed in baculovirus-infected insect cells demonstrated inhibitory activity against chymotrypsin (Ki 49.85 nM), but not trypsin, which defines a role for AvCI as a spider-derived chymotrypsin inhibitor. AvCI also exhibited inhibitory activity against microbial serine proteases such as subtilisin A (Ki 20.51 nM) and proteinase K (Ki 65.42 nM). Furthermore, AvCI exhibited no detectable inhibitory effects on factor Xa, thrombin, tissue plasminogen activator, or plasmin; however, AvCI strongly inhibited human neutrophil elastase (Ki 8.74 nM) and porcine pancreatic elastase (Ki 11.32 nM), indicating that AvCI acts as an anti-elastolytic factor. These findings constitute molecular evidence that AvCI acts as an inhibitor against chymotrypsin, microbial serine proteases, and elastases. This paper provides a novel view of the functions of a spider-derived chymotrypsin inhibitor.

Progressive elevation of ap-1 activity during preneoplastic-to-neoplastic progression as modeled in mouse jb6 cell variants

The JB6 mouse epidermal cell system has been used extensively as an in vitro model for the study of tumor promotion and progression. The present study was directed to assessing the role of basal AP-1 activity in JB6 variants which represent preneoplastic to neoplastic progression and to addressing whether AP-1 activity is required for maintenance of the tumor phenotype. Constitutively higher AP-1 activity was found in tumorigenic JB6 RT101 cells than in later or earlier preneoplastic P+ or P- cells. Levels of c-jun mRNA and protein correlated with progression stage. Enhancement of AP-1 activity by TPA increased the formation of anchorage independent colonies by tumorigenic RT101 cells. Inhibition of AP-1 activity by retinoic acid or fluocinolone acetonide inhibited expression of tumor phenotype as measured by AI growth. These data together with our previous results suggest that in the JB6 model (i) basal levels of Jun and AP-1 appear to be important for preneoplastic-to-neoplastic progression; (ii) induced AP-1 appears to be required for further progression by tumor cells; (iii) constitutively elevated AP-I activity may be important for the expression of transformed phenotype; (iv) inhibition of AP-1 activity by RA or FA is not a general suppression of transcription but is gene-specific; and (v) even though both inhibition of AP-1 activity and activation of RARE-dependent or GRE-dependent gene transcription correlate with inhibition of AI growth in RT101 cells by RA or FA, transactivation of RARE or GRE might better correlate with the inhibition of AI growth than the inhibition of AP-1 activity in RT101 cells.

Frequency of glycated hemoglobin monitoring was inversely associated with glycemic control of patients with Type 2 diabetes mellitus

BACKGROUND

The frequency of monitoring glycated hemoglobin (HbA(1c)) and its impact on glycemic control of Chinese Type 2 diabetes mellitus (T2DM) patients have not been well understood.

AIM

To explore the current status of the glycemic control, the frequency of HbA(1c) monitoring, and their relationship in T2DM outpatients in urban China.

SUBJECTS AND METHODS

A cross-sectional study was carried out in 15 hospitals purposely sampled from 4 cities of China. T2DM outpatients were consecutively recruited, and underwent a face-to-face interview in outpatient consulting rooms using a self-developed structured questionnaire to collect information. All consented patients were invited to have a free HbA(1c) test.

RESULTS

Among 1511 subjects, the average level of HbA(1c) was 8.1±1.6% with the ideal percents of 13.6% and 24.8% (HbA(1c)<6.5% and <7.0%, respectively). Less than 1/3 (339/1157) had received 2 or more HbA(1c) tests per yr, and they had a significantly lower average of HbA(1c) than those having only 1 or no test per yr (F=5.012, p=0.007). After adjustment for possible confounders including age, gender, and city, there was a significantly inverse association with adjusted odds ratios of 2.56 [95% confidence interval (CI): 1.71, 3.86] and 1.67 (95% CI: 1.11, 2.50), respectively, between the frequency of monitoring HbA(1c) (null, once vs ≥2 times per yr) and worse glycemic control (HbA(1c)≥7.0%).

CONCLUSIONS

Glycemic control of T2DM outpatients was poor in urban China. Frequency of HbA(1c) monitoring is seriously insufficient in majority of patients. Lower frequency of HbA(1c) monitoring is significantly associated with poor glycemic control.

Application of an ELISA-elution assay to dissociate digoxin-antibody complexes in immunoaffinity chromatography

In this study, we used a modified enzyme-linked immunosorbent assay (ELISA)-elution technique as a screening tool to select specific elution conditions. We examined 12 different elution conditions for the removal of antibodies from a complex on an ELISA plate; 0.2 mol/l glycine-HCl (pH 2.5), 1.0 mol/l acetic acid (pH 2.5), 25% methanol (pH 2.5) and 3 mol/l NaSCN showed a higher elution efficiency. We conducted affinity chromatography with these four conditions for the purification of anti-digoxin antibodies from hyperimmune sera with a digoxin-specific column using omega-aminoalkyl derivatives of Sepharose 4B, whose elution efficiency was similar to that of ELISA. We also monitored the relative specific activities during elution from the digoxin-specific column. The optimum, general-purpose dissociation reagent for this immunoaffinity system was identified as 25% methanol (pH 2.5) with an elution efficiency and relative specific activity of 88.40% and 62.25%, respectively. The high purity of the purified antibodies was demonstrated with sodium dodecyl sulphate-polyacrylamide gel electrophoresis.

Drug-metabolising enzyme polymorphisms and predisposition to anti-tuberculosis drug-induced liver injury: a meta-analysis

BACKGROUND

Although some case-control studies have investigated the association between drug-metabolising enzyme (DME) gene polymorphisms and susceptibility to anti-tuberculosis drug-induced liver injury (ATLI), their results are conflicting, mainly due to limited power.

OBJECTIVE

To review the literature systematically, by means of a meta-analytical review, to evaluate the putative association and provide a quantitative summary estimate on the association with ATLI.

DESIGN

We searched the databases of MEDLINE, PubMed, EMBASE and CBMdisc from 1966 to May 2007 using 'DME', 'hepatotoxicity', 'genetic polymorphism', 'genetic susceptibility' in combination with 'antitubercular agents', performed a manual search of citations from relevant original studies and review articles, and corresponded with authors.

RESULTS

Nine eligible articles were included in this meta-analysis, including five on N-acetyltransferase 2 (NAT2), four on cytochrome P450 2E1 (CYP2E1) and two on glutathione S-transferase (GST) studies, separately. The overall ORs of ATLI risk associated with NAT2 homozygous variant genotype (mt/mt), CYP2E1 homozygous wild genotype (*1A/*1A), GSTM1 homozygous null genotype (null/null) and GSTT1 homozygous null genotype (null/null) were respectively 1.93 (95%CI 0.81-4.62), 2.22 (95%CI 1.06-4.66), 2.62 (95%CI 1.45-4.75) and 1.18 (95%CI 0.61-2.29). In addition, the OR for Asian ATLI associated with the NAT2 homozygous variant (mt/mt) and the combined genotype (w/w + w/mt) was 2.52 (95%CI 1.49-4.26).

CONCLUSIONS

NAT2 mt/mt, CYP2E1*1A/*1A and GSTM1 null/null were observed to increase the risk of ATLI in tuberculosis patients. Our results support the hypothesis that NAT2 mt, CYP2E1*1A and GSTM1 null have a modest effect on genetic susceptibility to ATLI, but no significant evidence for GSTT1 null/null.

Fine mapping of E(kp)-1, a locus associated with silkworm (Bombyx mori) proleg development

The silkworm homeotic mutant E(kp) has a pair of rudimentary abdominal legs, called prolegs, in its A2 segment. This phenotype is caused by a single dominant mutation at the E(kp)-1 locus, which was previously mapped to chromosome 6. To explore the possible association of Hox genes with proleg development in the silkworm, a map-based cloning strategy was used to isolate the E(kp)-1 locus. Five E(kp)-1-linked simple sequence repeat markers on chromosome 6 were used to generate a low-resolution map with a total genetic distance of 39.5 cM. Four additional cleaved amplified polymorphic sequence markers were developed based on the initial map. The closest marker to E(kp)-1 was at a genetic distance of 2.7 cM. A high-resolution genetic map was constructed using nine BC1 segregating populations consisting of 2396 individuals. Recombination suppression was observed in the vicinity of E(kp)-1. Four molecular markers were tightly linked to E(kp)-1, and three were clustered with it. These markers were used to screen a BAC library. A single bacterial artificial chromosome (BAC) clone spanning the E(kp)-1 locus was identified, and E(kp)-1 was delimited to a region less than 220 kb long that included the Hox gene abdominal-A and a non-coding locus, iab-4. These results provide essential information for the isolation of this locus, which may shed light on the mechanism of proleg development in the silkworm and possibly in Lepidoptera.

Subthalamic nucleus stimulation for primary dystonia and tardive dystonia

With the renaissance of stereotactic pallidotomy for Parkinson's disease in 1990s, pallidotomy has become increasingly used as an effective treatment for various manifestations of medically refractory dystonia. More recently, deep brain stimulation of globus pallidus internus (GPi) has been replacing pallidotomy. Although GPi DBS has great promise for treating dystonia, there are some disadvantages. We introduce our experiences in subthalamic nucleus (STN) DBS for primary dystonia and tardive dystonia in this chapter. We propose that STN DBS has the following advantages over GPi DBS: (1) symptomatic improvement is seen immediately after stimulation, allowing us to quickly select the most suitable stimulation parameters; (2) the stimulation parameters for the STN are lower than those used for the GPi, resulting in longer battery life; and (3) STN DBS results in better symptomatic control than GPi DBS in dystonia patients when our STN data is compared to that obtained by others with using the GPi as the target. We suggest that STN DBS may be the most appropriate surgical technique for dystonia.

Decrease in density of INa is in the common final pathway to heart block in murine hearts overexpressing calcineurin

Overexpression of calcineurin in transgenic mouse heart results in massive cardiac hypertrophy followed by sudden death. Sudden deaths are caused by abrupt transitions from sinus rhythm to heart block (asystole) in calcineurin-overexpressing (CN) mice. Preliminary studies showed decreased maximum change in potential over time (d V/d tmax) of phase 0 of the action potential. Accordingly, the hypothesis was tested that decreased activity of the sodium channel contributes to heart block. Profound decreases in activity of sodium currents ( INa) paralleled the changes in action potential characteristics. Progressive age-dependent decreases were observed such that at 42–50 days of life little sodium channel function existed. However, this was not paralleled by decreased protein expression as assessed by immunocytochemistry or by Western blot. Since calcineurin can interact with the ryanodine receptor, we assessed whether chronic in vitro treatment with BAPTA-AM, thapsigargin, and ryanodine could rescue the decrease of INa. All of these treatments rescued INa to levels indistinguishable from wild type. The nonspecific PKC inhibitor bisindolylmaleimide I also rescued the decrease of INa. To assess whether decreased sodium channel activity contributes to sudden death in vivo, the response to encainide (20 mg/kg) was assessed: 6 of 10 young CN mice died because of asystole, whereas 0 of 10 wild-type mice died ( P < 0.01). Moreover, encainide produced exaggerated prolongation of the QRS width in sinus beats before the heart block. Catecholamine tone appears necessary to support life in older CN mice because propranolol (1 mg/kg) triggered asystolic death in five of six CN mice. We conclude that decrease in sodium channel activity is in the common final pathway to asystole in CN mice.

[Adverse drug reaction and rational use of levofloxacin: a prospective study]

OBJECTIVE

To study the rate of adverse drug reaction(ADR) and the rational use of levofloxacin among in-patients.

METHOD

All in-patients treated with levofloxacin were prospectively observed in 7 hospitals of Beijing.

RESULTS

One hundred and five ADR cases were found in 2,661 patients injected with levofloxacin. The ADR rate was 3.9% while 4.8% of them were classified as severe cases. All severe ADR cases had a nature of double infections. The ADR occurrence was related to older age, irrational drug use, combined medicine and allergic history. The rate of levofloxacin irrational use was 19.9%, especially in the elderly population, due to too long or too short course of treatments.

CONCLUSION

Levofloxacin is viewed as a safe injection in clinical practice, however, combined medicine and elderly patients should be paid more attention when on administration of this medication. The irrational use of levofloxacin was recognized as one of the main reasons causing the increase of ADR.

Bid is cleaved by calpain to an active fragment in vitro and during myocardial ischemia/reperfusion

Reperfusion after myocardial ischemia is associated with a rapid influx of calcium, leading to activation of various enzymes including calpain. Isolated perfused adult rabbit hearts subjected to global ischemia and reperfusion were studied. Calpain or a calpain-like activity was activated within 15 min after reperfusion, and preconditioning suppressed calpain activation. In contrast, caspase activation was not detected although cytochrome c was released after ischemia and reperfusion. The pro-apoptotic BH3-only Bcl-2 family member, Bid, was cleaved during ischemia/reperfusion in the adult rabbit heart. Recombinant Bid was cleaved by calpain to a fragment that was able to mediate cytochrome c release. The calpain cleavage site was mapped to a region within Bid that is extremely susceptible to proteolysis. These findings suggest that there is cross-talk between apoptotic and necrotic pathways in myocardial ischemia/reperfusion injury.

Ultrasound detection of blunt splenic injury

The purpose of this study was to determine the sensitivity of emergency ultrasound (US) for the detection of blunt splenic injury (BSI), and to describe sonographic parenchymal patterns. Over 3 years, 2138 emergency US were performed, and 162 patients had BSI. CT was performed for 76 patients, and there were 86 laparotomies. Seventy patients (43%) had concomitant intraabdominal injuries. Ultrasound detected free fluid in 109 patients (67%), and parenchymal injury in 31 patients (19%). There were 48 false negative US (30%). Sonographic patterns included a diffuse heterogeneous appearance, hyperechoic and hypoechoic perisplenic crescents, and discrete hypoechoic or hyperechoic areas within the spleen. Overall sensitivity of US for detection of BSI was 69%, but was 86% for grade III or higher injuries. Ultrasound is most sensitive for the detection of grade III or higher BSI based on the presence of haemoperitoneum. Ultrasound may also identify BSI on the basis of parenchymal abnormality, with a diffuse heterogeneous pattern most commonly encountered. Sonographic evaluation for both free fluid and parenchymal injury improves sensitivity of US.

[The relationship of low density lipoprotein receptor gene polymorphism and hyperlipidemia]

OBJECTIVE

To study the relationship of low density lipoprotein receptor gene polymorphism and hyperlipidemia in the population with essential hypertension.

METHODS

People with different lipid levels including 107 hyperlipidemia, 104 at margin level and 108 normal were recruited in the study. Their polymorphisms of LDL-R gene were analyzed using PCR-RFLP.

RESULTS

There were three kinds of genotype: (+/+), (+/-), (-/-). In male, the frequencies of the (+/-) in three study groups were shown as follows: 41.18% in hyperlipidemia, 46.15% in margin level, 19.05% in normal lipid. The frequency of (+) allele was significantly higher in hyperlipidemia than that in normal lipid (24.51%, 25.00% and 11.11%, respectively). In women, the differences were not statistically significant. The nonconditional univariate and multivariate logistic regression analysis demonstrated that (+) allele of Ava II polymorphism of LDL-R was a genetic marker of male's hypercholesterolemia.

CONCLUSIONS

The frequency of (+/-) hyperlipidemia in males was higher than that in normal lipid group and the (+) allele in male hyperlipidemia was significantly more frequent seen than that in normal lipid group. These results suggested that polymorphisms of LDL-Rgene might play an independent role of risk factor for hyperlipidemia.

Single subject research designs for disability research

PURPOSE

The objective of this article is to offer an overview of single subject designs and provide clinicians with information regarding the components of single subject designs and how they can be used in clinical and other rehabilitation environments.

METHOD/RESULT

Three basic designs in single subject research are presented, with corresponding examples illustrating each design. A review of visual and statistical analysis techniques commonly used in single subject designs is provided, and the advantages and limitations of each are noted.

CONCLUSION

Single subject designs are ideally suited for research in the rehabilitation practice environment. If properly applied, these designs can help establish the efficacy of rehabilitation practice and contribute to rehabilitation science.

Radio-frequency electrocautery ablation of mammary tissue in swine

PURPOSE

To establish the size, configuration, and histopathologic features of acute, subacute, and chronic radio-frequency (RF) electrocautery of mammary tissue in swine.

MATERIALS AND METHODS

Eighteen RF treatments were performed in the mammary tissue of three domestic swine under ultrasonographic (US) guidance. Histopathologic examination was performed immediately after (acute animal); 2 weeks after (subacute animal); and 4 weeks after (chronic animal) treatment.

RESULTS

In the acute animal, lesions were firm nodules on palpation and had a distinct line of demarcation between necrotic and viable mammary tissue (mean lesion volume, 14.24 cm(3); largest volume, 29.06 cm(3)). In the subacute animal, there was diffuse coagulation necrosis with neutrophilic infiltrates at the periphery (mean lesion volume, 6.46 cm(3); largest volume, 9.47 cm(3)), and two treatment areas had a secondary bacterial infection. In the chronic animal, lesions were still palpable and firm (mean lesion volume, 11.67 cm(3); largest volume, 25.5 cm(3)), and five of six treatment sites had an area of gray to white fibrotic tissue that blended with the surrounding tissue. However, one site had a pale yellow area of central necrosis surrounded by a fibrotic area. In both the subacute and chronic animals, two and one treatment site, respectively, had minimal areas of skin necrosis.

CONCLUSION

RF ablation of breast tissue is feasible in this animal model. Problems included minimal skin erythema, residual firm treatment regions at 4 weeks, slightly variable margins of coagulation necrosis, and occasional bacterial infection.