Co-expression effect of LLGL2 and SLC7A5 to predict prognosis in ERα-positive breast cancer

Lethal giant larvae homolog 2 (LLGL2) and solute carrier family 7 member 5 (SLC7A5) have been reported to be involved in resistance to endocrine therapy. This study aimed to assess the effects of LLGL2/SLC7A5 co-expression in predicting prognosis and response to tamoxifen therapy in ERα-positive breast cancer patients according to LLGL2/SLC7A5 mRNA and protein expression in long-term follow-up invasive breast cancer tissues. We identified that low LLGL2/SLC7A5 mRNA co-expression (LLGL2^low/SLC7A5^low) was associated with disease-free survival (DFS) compared with other combination groups in all breast cancer patients. In ERα-positive breast cancer patients, LLGL2^low/SLC7A5^low showed longer DFS and overall survival (OS) compared with LLGL2^high/SLC7A5^high and a positive trend of longer survival compared with the other combination groups. We also observed that LLGL2^low/SLC7A5^low showed longer survival compared with LLGL2^high/SLC7A5^high in ERα-positive breast cancer patients receiving adjuvant tamoxifen therapy. Multivariate analysis demonstrated that LLGL2^low/SLC7A5^low was an independent favorable prognostic factor of both DFS and OS, not only in all breast cancer patients, but also in ERα-positive breast cancer patients. High co-expression of LLGL2 and SLC7A5 protein showed a positive trend of shorter survival. Our study showed that co-expression of LLGL2 and SLC7A5 mRNA is a promising candidate biomarker in early breast cancer patients.

Discovering novel mechanisms of taxane resistance in human breast cancer by whole-exome sequencing

Taxanes are important drugs used in the treatment of breast cancer; however, some cancer types are taxane-resistant. The aim of the present study was to investigate the underlying mechanisms of taxane resistance using whole-exome sequencing (WES). Six patients with breast cancer whose tumors responded well to anthracycline treatment but grew rapidly during neoadjuvant taxane-based chemotherapy, were included in the present study. WES of samples from these patients was carried out to identify somatic mutations of candidate genes thought to affect taxane resistance, and the candidate proteins were structurally modeled. The mRNA and protein expression levels of these candidate genes in other breast cancers treated with taxanes were also examined. Nine variants common to all six patients were identified and two of these [R552P in V-type proton ATPase catalytic subunit A (ATP6V1A) and T114P in apolipoprotein B MRNA editing enzyme catalytic subunit 3F (APOBEC3F)] were selected. The results also showed that, protein-structure visualization suggested that these mutations may cause structural changes. The Kaplan-Meier analyses revealed that higher APT6V1A and APOBEC3F expression levels were significantly associated with poorer disease-free survival (DFS) and overall survival. Moreover, multivariate analysis identified high ATP6V1A mRNA expression as an independent risk factor for poor DFS. Two specific mutations that might affect taxane resistance were identified. Thus, these results suggest that breast cancer patients receiving taxanes who have high ATP6V1A or APOBEC3F expression levels may have shorter survival.

Low RAI2 expression is a marker of poor prognosis in breast cancer

PURPOSE

Retinoic acid-induced 2 (RAI2) has been shown to be a putative suppressor of the early hematogenous dissemination of tumor cells to the bone marrow in breast cancer. Here, we investigated the associations of RAI2 mRNA and protein expression with clinicopathological factors and prognosis in breast cancer patients with long-term follow-up.

METHODS

Invasive breast cancer tissues (n = 604) were analyzed for RAI2 mRNA expression. We examined the associations of clinicopathological factors with the expression levels of RAI2 mRNA in these samples. We also analyzed RAI2 protein expression by immunohistochemistry in invasive breast cancer tissues (n = 422).

RESULTS

We identified significant positive associations between low expression of RAI2 mRNA and shorter disease-free survival (DFS), breast-cancer-specific survival (BCSS), and overall survival (OS) in breast cancer patients. We also identified significant positive associations between negative for RAI2 protein expression and shorter DFS, BCSS, and OS in breast cancer patients. Low RAI2 mRNA and negative for RAI2 protein expression were positively associated with larger tumor size, higher tumor grade, and ERα-negativity. Multivariate analyses indicated that not only RAI2 mRNA but also RAI2 protein expression were independent risk factors for both DFS and BCSS in breast cancer patients. The median follow-up periods were 10.3 and 9.3 years for the RAI2 mRNA and protein expression analyses, respectively.

CONCLUSIONS

Our findings suggest that RAI2 has a role in the metastasis of breast cancer, and that RAI2 expression could be a promising candidate biomarker of prognosis in breast cancer patients.

Sentinel lymph node biopsy may be unnecessary for ductal carcinoma in situ of the breast that is small and diagnosed by preoperative biopsy

BACKGROUND

Current guidelines do not recommend that sentinel lymph node biopsy is routinely performed for ductal carcinoma in situ; thus, indications for sentinel lymph node biopsy in patients with ductal carcinoma in situ remain controversial. In this study, we investigated whether sentinel lymph node biopsy can be safely omitted when ductal carcinoma in situ has been diagnosed by preoperative biopsy.

METHODS

We retrospectively analysed sentinel lymph node metastasis rates and upstaging to invasive cancer in surgical specimens, performed receiver operating characteristic analysis for ductal carcinoma in situ lesion size and assessed correlations with preoperative clinicopathological factors of 277 patients with ductal carcinoma in situ diagnosed by preoperative biopsy at our institution.

RESULTS

Among 277 patients with sentinel lymph node biopsy, six (2.2%) had sentinel lymph node metastasis. All six were upstaged to invasive cancer by pathological examination of surgical specimens. In total, 69 patients (24.9%) were upstaged to invasive cancer. The mean size of ductal carcinoma in situ lesions on preoperative imaging was significantly larger for the 69 upstaged patients (50.0 mm) than for the non-upstaged patients (34.4 mm; P < 0.0001). Of the 277 patients with sentinel lymph node biopsy, 117 (42.2%) had preoperative ductal carcinoma in situ lesions <31.8 mm, which was identified as the optimal cut-off size by receiver operating characteristic analysis. Of these 117 patients, 96 (82.1%, 95% confidence interval: 73.9-88.5%) could be safely omitted from sentinel lymph node biopsy because all of them remained as ductal carcinoma in situ and had negative sentinel lymph nodes at surgery.

CONCLUSIONS

Size of ductal carcinoma in situ lesions on preoperative diagnostic imaging is a predictor of diagnosis of invasive cancer on pathological examination of surgical specimens. Sentinel lymph node biopsy may be unnecessary in ductal carcinoma in situ diagnosed by preoperative biopsy in patients with small lesions.

Abstract P6-07-03: The prognostic impact of HECTD1 E3 ubiquitin ligase expression in breast cancer patients

Background: The epithelial-to-mesenchymal transition (EMT) is fundamental and is required for cancer cells to metastasize. A E3 ubiquitin ligase, HECTD1,wasidentified as a potent regulator of EMT in breast cancer patients. Depletion of HECTD1 was reported to enhance EMT and migration. Here, we investigated the correlation of HECTD1 mRNA expression with prognosis in early breast cancer patients during long-term follow-up.

Materials and methods: A total of 627 invasive breast cancer tissues were analyzed for HECTD1 mRNA expression using a TaqMan PCR system. We also examined correlations between HECTD1 mRNA levels and clinicopathological factors in these samples. The median follow-up period was 10.2 years. Survival curves were analyzed using the Kaplan-Meier method. Cox proportional hazards regression analysis was used for univariate and multivariate analyses of prognostic values.

Results: We identified positive correlations between low HECTD1 mRNA levels and shorter disease-free survival (DFS) and overall survival (OS) in breast cancer patients (P=0.02 and P=0.03, respectively). Low HECTD1 mRNA levels were positively correlated with high tumor grade, ERα and PgR negativity, HER2 positivity, and type of adjuvant therapy. Univariate analysis indicated that low HECTD1 mRNA levels was a factor for poor DFS and OS in breast cancer patients (hazard ratio (HR), 1.43; 95% confidence interval (CI), 1.06-1.95 and HR, 1.49; 95% CI, 1.03-2.17, respectively) (Table 1).

Conclusion: We showed that low HECTD1 mRNA expression may be a predictive factor of poor prognosis in breast cancer patients. HECTD1 could therefore be a candidate biomarker and therapeutic target in breast cancer patients.

Table 1. Univariate Cox regression analysis of HECTD1 mRNA expression associated with prognosis.Patients (n=617)UnivariateDisease-free survivalOverall survivalp valueHR (95%CI)p valueHR (95%CI)HectD1 mRNA expressionhigh3130.021(Reference)0.031(Reference)low3141.43(1.06-1.95)1.49(1.03-2.17)

Citation Format: Yasuaki Uemoto, Naoto Kondo, Yumi Wanifuchi-Endo, Tomoko Asano, Tomoka Hisada, Sayaka Nishikawa, Yusuke Katagiri, Mitsuo Terada, Akiko Kato, Yu Dong, Hiroyuki Kato, Satoru Takahashi, Tatsuya Toyama. The prognostic impact of HECTD1 E3 ubiquitin ligase expression in breast cancer patients [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-07-03.

Abstract P6-04-11: LLGL2 is involved in resistance to tamoxifen in estrogen receptor-alpha positive breast cancer patients

Background: Resistance to endocrine therapy and metastatic progression is a leading cause of death in estrogen receptor-alpha(ERα)-positive breast cancer patients. Recently, the scaffolding protein LLGL2 was reported to promote cellular proliferation in ERα-positive breast cancer cells. LLGL2 forms a trimetric complex with the leucine transport protein SLC7A5. LLGL2 and SLC7A5 were reported to be involved in resistance to tamoxifen treatment. Here, we investigated LLGL2 and SLC7A5 mRNA expression in breast cancer patients during long-term follow-up.

Materials and methods: A total of 627 invasive breast cancer tissues was available for analysis of LLGL2 mRNA using a TaqMan PCR system. We sought correlations between clinicopathological factors and levels of LLGL2 expression in these samples. We also examined the mRNA expression of SLC7A5. The median follow-up period was 10.8 years. Survival curves were analyzed using the Kaplan-Meier method. Cox proportional hazards regression analysis was used for univariate and multivariate analyses of prognostic values. Receiver operating characteristic (ROC) analysis was performed to determine the cut-off values of LLGL2 and SLC7A5 mRNA expression in breast cancers.

Results: We found a positive correlation between high expression of LLGL2 mRNA and shorter disease-free survival (DFS) in all patients analyzed (P=0.01). We also identified positive correlations between high expression of LLGL2 mRNA and shorter DFS and overall survival (OS) in ERα-positive breast cancer patients (P=0.0006 and P=0.004, respectively), and but not in ERα-negative patients (P=0.67 and P=0.63, respectively).

Positive correlations of LLGL2 mRNA expression with DFS and OS were observed in ERα-positive patients who received tamoxifen as an adjuvant therapy (P=0.02 and P=0.03, respectively). We also found positive correlations of SLC7A5 mRNA expression with DFS and OS in ERα-positive patients who received tamoxifen as an adjuvant therapy (P=0.006 and P=0.049, respectively); interestingly, this was not observed in ERα-positive patients who did not receive tamoxifen. Multivariate analysis indicated that high LLGL2 mRNA expression was an independent factor for prognosis both in breast cancer patients overall (Table 1) and ERα-positive breast cancer patients.

Conclusion: LLGL2 and SLC7A5 expression levels are associated with the prognosis of ERα-positive breast cancer patients, especially those who receive tamoxifen as an adjuvant therapy. Furthermore, higher expression of LLGL2 is an independent predictive factor of poor prognosis in ERα-positive breast cancer patients. LLGL2 and SLC7A5 could be promising candidate biomarkers and therapeutic targets in ERα-positive breast cancer patients who receive tamoxifen as an adjuvant therapy.

Table 1. Multivariate Cox regression analysis of factors associated with prognosis in all breast cancer patients.Variablesn (%)Multivariate (DFS)P valueHR (95% CI)Tumor size≤ 2cm241 (38)1&gt; 2cm383 (61)0.4771.14 (0.8-1.64)Node statusNegative340 (54)1Positive253 (40)&lt;0.00013.7 (2.61-5.25)Grade1164 (263)12 and 3445(71)0.0221.67 (1.07-2.69)ER statusPositive486 (77)1Negative131(21)0.0971.59 (0.92-2.75)LLGL2 mRNALow340 (54)1High287 (46)0.0231.46 (1.05-2.03)

Citation Format: Tomoka Hisada, Naoto Kondo, Yumi Endo, Tomoko Asano, Yasuaki Uemoto, Sayaka Nishikawa, Yusuke Katagiri, Mitsuo Terada, Akiko Kato, Yu Dong, Hiroyuki Kato, Satoru Takahashi, Tatsuya Toyama. LLGL2 is involved in resistance to tamoxifen in estrogen receptor-alpha positive breast cancer patients [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-04-11.

P5631The impact of plaque type on strut embedment/protrusion and shear stress distribution in bioresorbable scaffold

Background and aim

Scaffold design and plaque characteristics influence implantation outcomes and local flow dynamics in treated coronary segments. Our aim is to assess the impact of strut embedment/protrusion of bioresorbable scaffold on local shear stress distribution in different atherosclerotic plaque types.

Method

Fifteen Absorb everolimus-eluting Bioresorbable Vascular Scaffolds were implanted in human epicardial coronary arteries. Optical coherence tomography (OCT) was performed post-scaffold implantation and strut embedment/protrusion were analyzed using a dedicated software. OCT data was fused with angiography to reconstruct three-dimensional coronary anatomy. Blood flow simulation was performed and wall shear stress (WSS) was estimated in each scaffolded surface and the relationship between strut embedment/protrusion and WSS was evaluated.

Results

There were 9083 struts analysed. Ninety-seven percent of the struts (n=8840) were well apposed and 243 (3%) were malapposed. At cross-section level (n=1289), strut embedment was significantly increased in fibroatheromatous plaques (76±48μm) and decreased in fibro-calcific plaques (35±52 μm). Compatible with strut embedment, WSS was significantly higher in lipid-rich fibroatheromatous plaques (1.50±0.81Pa), whereas significantly decreased in fibro-calcified plaques (1.05±0.91Pa). After categorization of WSS as low (<1.0 Pa) and normal/high WSS (≥1.0 Pa), the percent of low-WSS in the plaque subgroups were 30.1%, 31.1%, 25.4% and 36.2% for non-diseased vessel wall, fibrous plaque, fibro-atheromatous plaque and fibro-calcific plaque, respectively (p-overall<0.001).

Table 1. Cross-section level Embedment/Protrusion and WSS according to the plaque type Plaque type Embedment depth (μm) Protrusion distance (μm) WSS (Pa) Non-atherosclerotic intimal thickening/normal vessel wall (n=2275) 47±34*Δ¥ 123±34¶Ξπ 1.44±0.9解 Fibrous (n=4191) 53±40*#& 118±38¶Ψ‡ 1.24±0.78αθ∞ Fibroatheromatous (n=2027) 76±48#ΦΔ 94.6±46Ω†Ψπ 1.50±0.81Σ§α Fibro-calcific (n=590) 35±52&Φ¥ 139±50‡†Ξ 1.05±0.91∞£Σ For embedment: *p=0.09, #p<0.001, &p<0.001, Φp<0.0001, Δp<0.0001, ¥p<0.0001. For protrusion: ¶p=0.74, Ξp<0.0001, πp<0.0001, Ψp<0.0001, ‡p<0.0001, †p<0.0001. For WSS: θp<0.001, §p=0.06, £p<0.0001, αp<0.0001, ∞p<0.0001, Ωp<0.0001. n=total strut number in each plaque type, p-values come from mixed-effects regression analysis.

Conclusion

The composition of the underlying plaque influences strut embedment which seems to have effect on WSS. The struts deeply embedded in lipid-rich fibroatheromas plaques resulted in higher WSS compared to the other plaque types.

P5629The effect of strut protrusion on local shear stress and neointimal hyperplasia

Objective

To evaluate effect of strut protrusion (SP) on wall shear stress (WSS) and neointimal growth (NG) 1 and 5 year after implantation of Absorb scaffold.

Method

8 patients were selected from Absorb Cohort B. After 3-dimensional reconstruction of coronaries, WSS was quantified using Newtonian steady flow simulation (Figure). At 1-year neointimal thickness (NT) was measured by optical coherence tomography and correlated to WSS and SP post-procedure.

Results

Median SP was 112.9 (90.8, 133.1) μm. A logarithmic (log) inverse relationship between SP and post-procedure WSS (r=−0.425 p<0.001 correlation coefficients range: −0.143 to −0.553) was observed whereas a correlation between baseline log transformed WSS and NT (r=−0.451 p<0.001 correlation coefficients range: −0.140 to −0.662) was documented at 1 year. Mixed effects analysis between baseline log transformed WSS and NT at follow up yielded a slope of 30 μm/ln Pascal (Pa) and a y-intercept of 98 μm. As result of NG, flow area decreased from 6.91 (6.53, 7.48) mm2 post-implantation to 5.65 (5.47, 6.02) mm2 at 1 year (p=0.01) and to 5.75±1.37 mm2 at 5 years (p=0.024). Vessel surface with low WSS (<1 Pa) decreased from post-procedure (42%) to 1 year (35.9%) and 5 years (15.2%) (p-overall<0.0001).

Conclusion

SP disturbs laminar flow, creates region of low WSS that is mechanistically associated with NG and lumen area reduction. This observation would suggest thin strut with effective embedment would reduce NG and improve WSS towards physiological values.

Abstract P2-08-37: The prognostic impact of synaptojanin 2 expression in estrogen receptor α-positive breast cancer patients

Background: Synaptojanin 2 (SYNJ2) was reported to be a druggable mediator of metastasis. It is overexpressed and amplified in breast cancer, particularly estrogen receptor α (ERα)-positive breast cancer. SYNJ2 was also shown to promote cell migration and invasion in breast cancer xenograft cultures and lung metastasis in mice. Here, we investigated SYNJ2 mRNA expression in breast cancer patients during long-term follow-up.

Materials and methods: A total of 434 invasive breast cancer tissues were analyzed for SYNJ2mRNA expression using TaqMan PCR, and the correlation of this expression with patient clinicopathological factors was determined. We also examined the expression of markers associated with tumor-initiating capacity, such as SNAI1, SNAI2, and VIM. Survival curves were analyzed using the Kaplan–Meier method. Cox proportional hazards regression analysis was used for univariate and multivariate analyses of prognostic values.

Results: The median follow-up period was 10.7 years. We found positive correlations between high expression of SYNJ2 mRNA and shorter disease-free survival in breast cancer patients (P=0.049), which was limited to ERα-positive patients (P=0.020) and not seen in ERα-negative patients (P=0.863). High SYNJ2 mRNA levels were positively correlated with high tumor grade, ERα negativity, and node positivity. Multivariate analysis indicated that high SYNJ2 mRNA expression was an independent factor for poor disease-free survival in breast cancer patients.

Multivariate analysis of poor disease-free survival   DFS    Mutivariate   All patientsp valueHR (95%CI)Tumor size2cm and fewer1540.43151 (Reference) more than 2cm280 1.19 (0.78-1.85)Lymph node metastasisNegative2190.0001 and fewer1 (Reference) Positive184 5.61 (3.59-9.05) Unknown31 2.40 (0.89-5.48)Grade1,22330.38471 (Reference) 3195 1.20 (0.79-1.81) Unknown6 0.17 (1.78-3.49)ER statusPositive3370.02621 (Reference) Negative97 2.06 (1.87-4.07)PgR statusPositive2930.39511 (Reference) Negative141 1.30 (0.70-2.28)SYNJ2 mRNA expressionlow2170.02251 (Reference) high217 1.57 (1.07-2.34)

Conclusion:High SYNJ2 expression was shown to be an independent predictive factor of poor prognosis in ERα-positive breast cancer patients. SYNJ2 could therefore be used as a candidate biomarker and therapeutic target in breast cancer.

Citation Format: Nishikawa S, Kondo N, Wanifuchi-Endo Y, Hisada T, Uemoto Y, Katagiri Y, Dong Y, Kato H, Takahashi S, Toyama T. The prognostic impact of synaptojanin 2 expression in estrogen receptor α-positive breast cancer patients [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-08-37.

Abstract P3-03-34: Sentinel lymph node biopsy is unnecessary in ductal carcinoma in situ patients diagnosed by biopsy

Background: Japanese Breast Cancer Society Clinical Practice Guidelines for Breast Cancer 2018 state that sentinel lymph node (SN) biopsy is unnecessary for patients treated with breast-conserving therapy (BCT) and with an expected final pathological diagnosis of ductal carcinoma in situ (DCIS). Regardless of whether they were diagnosed with DCIS by biopsy before surgery, 78% of patients currently undergo axial procedures in Japan because invasive lesions may be detected in surgical specimens. This study examined whether SN biopsy can be omitted in DCIS patients diagnosed by biopsy and which factors are associated with invasion.

Methods: Patients who underwent definitive surgery for DCIS diagnosed by preoperative biopsy at our institution from May 2004 to January 2018 were investigated retrospectively. The factors associated with upstaging to invasive cancer from DCIS were examined with Fisher's exact test and the t-test. (Age, Tumor size, Operation (Mastectomy or BCT), Biopsy method (Core Needle Biopsy or Vaccume-Assisted Biopsy), Mammography (ditected or not-detected), Ultrasound (ditected or not-detected, mass or non-mass), Comedo, ER, PgR, HER2)

Results: A total of 311 patients were enrolled in this study, of whom 277 (89.1%) underwent SN; six of these (2.2%) had SN metastasis. All six cases were upstaging to invasive cancer: five (1.8%) had micrometastasis and one had macrometastasis (0.4%). From a surgical viewpoint, SN metastasis were detected in 3/161 (1.9%) cases treated with mastectomy and 3/150 (2.4%) cases treated with BCT. Although all three cases treated with BCT had micrometastasis, one case treated with mastectomy had macrometastasis (the other two cases had micrometatastasis). A total of 80/311 cases (25.7%) upstaged to invasive cancer and the only predictor of invasion was tumor size on images (p=0.0002). We could not determine the effective cut-off for tumor size because the area under the receiver operating characteristic curve was 0.63&lt;0.70.

Tabule 1.Tumor size on images was the only predictor of invasion. Upstaging (N=80)DCIS (N=231)P valueTumor size: mm (95% Confidence Interval)47.5 (41.9-53.2)33.9 (30.5-37.3)0.0002

Conclusion: Tumor size was found to be the only predictor of invasion. Only 2.2% of DCIS patients had SN metastasis despite the fact that 25.7% patients were upstaged to invasive cancer. We conclude that SN biopsy is not necessary for DCIS patients diagnosed by biopsy.

Citation Format: Uemoto Y, Kondo N, Wanifuchi-Endo Y, Hisada T, Nishikawa S, Katagiri Y, Kato H, Takahashi S, Toyama T. Sentinel lymph node biopsy is unnecessary in ductal carcinoma in situ patients diagnosed by biopsy [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-03-34.

Anisotropic atomic-structure related anomalous Hall resistance in few-layer black phosphorus

Specific anisotropic-atomic-structure of atom-thin black phosphorus causes the anomalous magnetic-field dependence of the Hall resistance, which opens doors to novel quantum phenomena and innovative two-dimensional atom-thin devices.

Gate-Tunable Atomically Thin Lateral MoS2 Schottky Junction Patterned by Electron Beam

Among atomically thin two-dimensional (2D) materials, molybdenum disulfide (MoS2) is attracting considerable attention because of its direct bandgap in the 2H-semiconducting phase. On the other hand, a 1T-metallic phase has been revealed, bringing complementary application. Recently, thanks to top-down fabrication using electron beam (EB) irradiation techniques, in-plane 1T-metal/2H-semiconductor lateral (Schottky) MoS2 junctions were demonstrated, opening a path toward the co-integration of active and passive two-dimensional devices. Here, we report the first transport measurements evidencing the formation of a MoS2 Schottky barrier (SB) junction with barrier height of 0.13-0.18 eV created at the interface between EB-irradiated (1T)/nonirradiated (2H) regions. Our experimental findings, supported by state-of-the-art simulation, reveal unique device fingerprint of SB-based field-effect transistors made from atom-thin 1T layers.

Effect of Fenbufen on the Entry of New Quinolones, Norfloxacin and Ofloxacin, into the Central Nervous System in Rats

The entry of two new quinolone antibacterial agents, norfloxacin and ofloxacin, into the central nervous system (CNS) of rats, and the effect of fenbufen on this was investigated. At various times after the administration of a bolus intravenous dose of norfloxacin or ofloxacin (10 mg kg−1) with or without fenbufen (20 mg kg−1), serum and cerebrospinal fluid (CSF) samples and whole brain were collected from the rats and the concentration of norfloxacin or ofloxacin in each sample was determined. Serum concentrations of both quinolones declined biexponentially with time and were significantly elevated by coadministration with fenbufen at the terminal phase. The fractions of these quinolones bound to serum protein were not altered by coadministration with fenbufen. Coadministered fenbufen raised the brain concentrations of both quinolones but did not affect their brain to serum unbound concentration ratios. In contrast, CSF to serum unbound concentration ratios as well as CSF concentrations of norfloxacin and ofloxacin were elevated by coadministration with fenbufen. Apparent diffusional clearances between blood and CSF of norfloxacin and ofloxacin estimated by the physiological model analysis increased by 1·9 and 2·6 times, respectively, after coadministration with fenbufen. These findings suggest that coadministered fenbufen may facilitate the entry of norfloxacin and ofloxacin into the CNS.

Salivary excretion of mexiletine after bolus intravenous administration in rats

Salivary excretion of mexiletine was investigated following bolus intravenous administration (10 mg kg−1) in rats. Parotid and mandibular saliva was collected separately by stimulating salivation with constant rate infusion of pilocarpine (3 mg kg−1 h−1). The mexiletine levels in blood plasma and parotid and mandibular saliva declined biexponentially with time in almost parallel fashion. Although the mexiletine levels in both types of saliva were lower than that in plasma, the drug level in parotid saliva was always higher than that in mandibular saliva. Significant correlations were observed when all data relating mexiletine concentration in plasma and saliva were included (P &lt; 0·001). The saliva/plasma drug concentration ratios (S/P ratios) did not vary to a large extent (0·56 ± 0·10 for parotid saliva, 0·21 ± 0·06 for mandibular saliva), but there was a consistent tendency for the higher plasma drug levels in the distribution phase to produce relatively high S/P ratios for both parotid and mandibular saliva. Moreover, the plasma mexiletine levels calculated by the equation of Matin et al (1974) employing the observed values for the saliva drug level, saliva pH and free fraction of mexiletine in plasma were significantly higher than the observed drug levels. Therefore, it is suggested that the salivary excretion of mexiletine could not be explained quantitatively by simple, passive secretion based on pH-partition theory.

Intracytoplasmic sperm injection. Accomplishments and qualms

AIM

Intracytoplasmic sperm injection (ICSI) is now the preferred technique for treatment of male factor infertility and many children have been born worldwide. However, concerns about the risk of transmitting genetic defects and development of ICSI children have been raised. We report clinical outcome of ICSI in Cornell University and results of screening for genetic defects in ICSI parents and their children.

METHODS

Pregnancy and obstetrical outcomes as well as congenital malformations were analyzed. Chromosomal karyotyping and Yq deletion assessments were performed on blood samples. In addition, medical and developmental outcome were assessed in 3 and 5 year old ICSI children.

RESULTS

We have performed 8 575 ICSI cycles with ejaculated spermatozoa that resulted in a 75.4% fertilization and a 42.8% clinical pregnancy rates while for surgically retrieved specimen resulted in 66%, 48.8% respectively. The incidence of Y deletion was within the expected range for an infertile population, with identical deletions transmitted to the male offspring. There were no differences in cognitive, motor and behavioral development observed between ICSI children and these conceived naturally.

CONCLUSION

The large majority of infertile men were treatable by ICSI, which resulted in the transmission of a specific abnormality but did not enhance the incidence of de novo deletions. There is no indication that ICSI children develop more congenital defects or express a lower psychomotor development that children conceived naturally. Nonetheless, genetic screening and counseling of couples undergoing ICSI would seem to be appropriate.

Application of intracytoplasmic sperm injection in assisted reproductive technologies

Intracytoplasmic sperm injection (ICSI) entails the mechanical insertion of a chosen spermatozoon directly into the cytoplasm of an oocyte. Due to the consistent fertilization and pregnancy outcome, ICSI is routinely used to treat azoospermic patients where spermatozoa are retrieved by epididymal aspiration or testicular biopsy. Since male subfertility has been associated with a higher incidence of genomic defects, ranging from numerical chromosomal abnormalities to Yq microdeletions, concerns have been raised as to the risk of transmitting genetic defects to the offspring. Screening for such defects can provide invaluable information for appropriate counselling prior to ICSI treatment. In order to address these concerns, a follow-up of the children born after ICSI treatment was conducted.

Vagal stimulation prior to atrial rapid pacing protects the atrium from electrical remodeling in anesthetized dogs

Atrial electrical remodeling is thought to be the cause of the maintenance of atrial fibrillation (AF). Although the initiation and maintenance of AF is partially associated with autonomic nervous tone, vagally mediated AF does not tend to become permanent. Therefore, the effects of preceding vagal stimulation (VS) on the atrial effective refractory period (ERP) under electrical remodeling conditions were investigated in anesthetized dogs. Atrial ERPs were measured at 5 sites before and after a 7-h period of atrial rapid pacing in the control group. In the VS group, the vagus nerve was stimulated for 20 min before a period of atrial rapid pacing. Atrial rapid pacing shortened the ERP at each site in the control group (electrical remodeling). On the other hand, atrial rapid pacing after VS did not shorten the ERP at any site in the VS group. Tetrodotoxin, which was administered into the fatty tissue overlying the right atrial side of the right pulmonary vein junctions, blocked the protective effect of VS against the shortening of the ERP induced by atrial rapid pacing. In contrast, atropine did not interfere with such protective effects. These results suggest that VS prior to atrial rapid pacing protects the atrium from atrial electrical remodeling.