Probing the Interaction at the Nano-Bio Interface Using Raman Spectroscopy: ZnO Nanoparticles and Adenosine Triphosphate Biomolecules

With the advent of nanobiotechnology, there will be an increase in the interaction between engineered nanomaterials and biomolecules. Nanoconjugates with cells, organelles, and intracellular structures containing DNA, RNA, and proteins establish sequences of nano-bio boundaries that depend on several intricate complex biophysicochemical reactions. Given the complexity of these interactions, and their import in governing life at the molecular level, it is extremely important to begin to understand such nanoparticle-biomaterial association. Here we report a unique method of probing the kinematics between an energy biomolecule, adenosine triphosphate (ATP), and hydrothermally synthesized ZnO nanostructures using micro Raman spectroscopy, X-ray diffraction, and electron microscopy experiments. For the first time we have shown by Raman spectroscopy analysis that the ZnO nanostructures interact strongly with the nitrogen (N₇) atom in the adenine ring of the ATP biomolecule. Raman spectroscopy also confirms the importance of nucleotide base NH₂ group hydrogen bonding with water molecules and phosphate group ionization and their pH dependence. Calculation of molecular bond force constants from Raman spectroscopy reinforces our experimental data. These data present convincing evidence of pH-dependent interactions between ATP and zinc oxide nanomaterials. Significantly, Raman spectroscopy is able to probe such difficult to study and subtle nano-bio interactions and may be applied to elegantly elucidate the nano-bio interface more generally.

Diagnostic approach to primary immunodeficiency disorders

Primary immunodeficiency disorders (PIDs) are a heterogeneous group of inherited disorders that affect different components of the immune system. There are more than 150 different disorders which have been described till date. Despite major advances in the molecular characterization of PIDs over the last 20 years, many patients remain undiagnosed or are diagnosed too late with severe consequences. Recognizing different clinical manifestations of PID is the first most important step. It should be followed by use of appropriate diagnostic tools from a vast number of investigations available. This review will focus on important presenting features of PID and laboratory approach for diagnosis of suspected cases of PID.

The angiotensin-converting enzyme gene insertion/deletion polymorphism in Indian patients with vitiligo: a case-control study and meta-analysis

BACKGROUND

Vitiligo is a common, acquired, idiopathic depigmenting skin disorder. Although the exact pathogenesis remains unknown, genetic susceptibility and autoimmune responses play a role in vitiligo development. Previous studies have suggested that the D allele of the insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene is associated with vitiligo in Indians and Koreans. Furthermore, significantly higher serum ACE levels have been demonstrated in patients with some autoimmune and autoinflammatory disorders.

OBJECTIVES

The objectives were to investigate any association between the ACE I/D polymorphism and vitiligo susceptibility in an Indian population, and to compare serum ACE levels in patients with vitiligo and healthy subjects.

METHODS

The ACE I/D genotypes of 79 patients with vitiligo and 100 normal individuals were determined by polymerase chain reaction amplification. A meta-analysis was done to compare the distribution of the ACE I/D alleles and genotypes in the current and three previous studies. Serum ACE levels were evaluated by enzyme-linked immunosorbent assay.

RESULTS

A significant increase in the frequency of the ACE I/D D allele was evident in patients with vitiligo in both the case-control study [P=0·005; odds ratio (OR) 1·87; 95% confidence intervals (CI) 1·22-2·85] and the meta-analysis (P=0·044; OR 1·44; 95% CI 1·01-2·06). Serum ACE levels were significantly increased in patients with vitiligo compared with healthy subjects (P<0·0001).

CONCLUSIONS

In agreement with earlier reports, the ACE I/D D allele is associated with vitiligo susceptibility in the Indian population. The significantly elevated serum ACE levels in our cohort of patients with vitiligo concur with those previously found in patients with some other autoimmune diseases.

Anti-C reactive protein antibodies in Indian patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is characterized by over production of autoantibodies. C-reactive protein (CRP) is a phylogenetically highly conserved plasma protein that participates in the systemic response to inflammation. Anti-CRP antibodies might have biological functions of pathogenetic interest in SLE. We evaluated anti-CRP antibodies in Indian SLE patients and their association with anti-dsDNA antibodies and complement levels (C3 and C4). One hundred SLE patients diagnosed according to the American College of Rheumatology criteria were included. Disease activity was assessed using SLE disease activity index (SLEDAI). Anti-CRP autoantibodies were detected by enzyme linked immunosorbent assay. Anti-dsDNA antibodies were detected by indirect immunofluroscence test (Euroimmun Lubeck, Germany). High sensitivity CRP and complement levels (C3, C4) were detected using a Nephelometer. (BN ProSpec, Dade Behring, Germany). Anti-CRP antibodies were detected in 26% of SLE patients. Mean age of disease onset among anti-CRP positives was 22.4 ± 7.5, and 26.6 ± 9.3 years among anti-CRP negatives (P > 0.05). Anti-dsDNA positivity was significantly higher among anti-CRP positives (32.7%) as compared to anti-CRP negatives (16%) (P = 0.00519). No statistically significant difference was observed in SLEDAI scores of anti-CRP positive group and anti-CRP negative group (P > 0.05). We observed a positive correlation between anti-CRP antibodies and anti-dsDNA antibodies.

Acquired von Willebrand syndrome: a rare disorder of heterogeneous etiology

CONTEXT

Acquired von Willebrand syndrome (AVWS) is a rare bleeding disorder that mimics the inherited form of von Willebrand disease (VWD) in terms of laboratory findings and clinical presentation.

AIMS

To study the etiology of acquired VWD.

SETTINGS AND DESIGN

The patients referred from various hospitals in and out of Mumbai were included in the study.

MATERIALS AND METHODS

Six patients with AVWS diagnosed at this center over the last 10 years were analyzed against 171 patients with inherited VWD. The differential diagnosis of AVWS was made based on reduced levels of von Willebrand antigen and von Willebrand ristocetin cofactor, decrease in ristocetin induced platelet aggregation, absence of correction in mixing studies with no prior history of bleeding problems and a negative family history for bleeding disorders.

RESULTS

In three patients, the disease was associated with systematic lupus erythematosus, out of which one was also associated with Kikuchi lymphadenitis and second with autoimmune hemolytic anemia. Fourth case was associated with hypothyroidism and fifth was a case of dermatitis and vitiligo. The last patient was a case of hemophilia A with Burkitts lymphoma, who developed autoantibodies to von Willebrand factor. Except two patients, all other patients responded to immune suppressive therapy with corticosteroids, while the patient with hypothyroidism responded to oral thyroxine.

CONCLUSION

AVWS is a rare condition and may often be missed or diagnosed as inherited disease associated with heterogeneous disease conditions.

Detection of fetal mutations causing hemoglobinopathies by non-invasive prenatal diagnosis from maternal plasma

BACKGROUND

Prenatal diagnosis of hemoglobinopathies enables couples at risk to have a healthy child. Currently used fetal sampling procedures are invasive with some risk of miscarriage. A non-invasive approach to obtain fetal deoxyribonucleic acid (DNA) for diagnosis would eliminate this risk.

AIM

To develop and evaluate a non-invasive prenatal diagnostic approach for hemoglobinopathies using cell-free fetal DNA circulating in the maternal plasma.

SETTINGS AND DESIGN

Couples referred to us for prenatal diagnosis of hemoglobinopathies where the maternal and paternal mutations were different were included in the study.

MATERIALS AND METHODS

Maternal peripheral blood was collected at different periods of gestation before the invasive fetal sampling procedure was done. The blood was centrifuged to isolate the plasma and prepare DNA. A size separation approach was used to isolate fetal DNA. Nested polymerase chain reaction (PCR)-based protocols were developed for detection of the presence or absence of the paternal mutation.

RESULTS AND CONCLUSIONS

There were 30 couples where the parental mutations were different. Of these, in 14 cases the paternal mutation was absent and in 16 cases it was present in the fetus. Using cell-free fetal DNA from maternal plasma, the absence of the paternal mutation was accurately determined in 12 of the 14 cases and the presence of the paternal mutation was correctly identified in 12 of the 16 cases. Thus, this non-invasive approach gave comparable results to those obtained by the conventional invasive fetal sampling methods in 24 cases giving an accuracy of 80.0%. Although the nested PCR approach enabled amplification of small quantities of cell-free DNA from maternal plasma at different periods of gestation after size separation to eliminate the more abundant maternal DNA, an accurate diagnosis of the presence or absence of the paternal mutation in the fetus was not possible in all cases to make it clinically applicable.

Abstract P4-12-03: Towards a risk prediction model for breast cancer that utilizes breast tissue risk features

Background: Optimal early detection and prevention strategies for breast cancer are predicated on our ability to accurately identify women at increased risk for disease. Current breast cancer risk prediction models rely on clinical and epidemiologic features. As demonstrated with other cancers, such as those of the cervix and colon, cancer risk assessment is enhanced when the tissue at risk is examined for evidence of premalignant abnormalities. Here, we present a multivariate model for individualized breast cancer risk prediction that incorporates tissue features identified from biopsies from women with benign breast disease (BBD).

Methods: We used our cohort of more than 9000 women diagnosed with BBD at the Mayo Clinic from 1967–1991, and identified a nested case:control series of 377 women who developed cancer (cases) matched with 734 women who did not (controls). We identified a set of variables that either alone or in two-way interactions contributed to a multivariable risk prediction model. We combined this relative risk model with the baseline incidence of breast cancer and the baseline hazard of death from our full BBD cohort to develop a risk prediction tool that computes absolute risk estimates for breast cancer. We calculated 5-year risk predictions for these cases and controls using our model and using the Gail model and compared c-statistics from these risk predictions. We validated our model using an independent set of 378 breast cancer cases and 728 matched controls drawn from our BBD cohort.

Results: Cases and controls in the model development data set differed significantly on a number of features when examined individually. Those included in a multivariable relative risk model for breast cancer among women with BBD are shown below.

Abstract P5-01-08: Complex fibroadenoma is not an independent risk marker for breast cancer

Background: Fibroadenoma (FA) is a relatively common benign breast tumor that can occur in women of any age, with a peak incidence during the second and third decades. The only previous study of this lesion reported that FAs are associated with a 2.2 times increased risk of developing invasive breast cancer (BC) compared to matched controls [1]. This relative risk may increase to 3.1 among patients with complex FA, and remains elevated for decades after diagnosis. However, this study did not thoroughly account for other forms of concomitant risk factors. Our investigative team sought to examine breast cancer risk among women with non-complex and complex FA, overall and stratified by other BC risk factors.

Materials and Methods: The study cohort included women between ages 18 to 85 in the Mayo Benign Breast Disease (BBD) Cohort who underwent excisional breast biopsy between 1967and1991 and were found to have a FA. FA was defined histologically as a combination of epithelial and stromal proliferation. Complex FA was defined as FA associated with any of the following features: sclerosing adenosis, epithelial calcifications, papillary apocrine change, and microcysts greater than 3.0 mm. The primary endpoint was a diagnosis of BC, determined using the Mayo medical record and questionnaire information from study participants. A single breast pathologist, blinded to the initial diagnosis and clinical outcome, performed pathology review. Observed vs. expected BC risk across levels of FA was assessed via standardized incidence ratios (SIRs), using age-stratified incidence rates from the Iowa Surveillance, Epidemiology, and End Results (SEER) registry. Analyses were carried out overall and within subgroups of involution status (none, partial, complete) and overall histology (non-proliferative disease [NP], proliferative disease without atypia [PDWA] or atypical hyperplasia [AH]).

Results: Of 9097 women in the Mayo BBD Cohort, FA were identified in 2139- non-complex in 1903 (20.9%) and complex in 236 (2.6%). The greatest proportion of FA occurred in the 40–69 age range. The mean ages for women with non-complex FA and complex FA were 45.7 and 50.2 years respectively. The SIR of breast cancer in the overall BBD cohort was 1.5 (95% CI [1.4–1.6]). The SIR among women with non-complex FA was 1.5 (95% CI [1.3–1.8]), and for complex FA increased to 2.41 (95% CI [1.7–3.4]). However, women with complex FA were more likely to have other concomitant high-risk histologic features such as PDWA and incomplete involution. In stratified analyses accounting for involution status and PDWA, complex FA did not demonstrate an independent increase in BC risk.

Conclusion: Complex FA does not confer an increased risk for BC beyond other established histologic features. Therefore, women with complex FA should be managed based upon a risk level consistent with the major histologic category of PDWA and/or AH.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-01-08.

Abstract P1-01-22: The utility of axillary ultrasound and sentinel lymph node biopsy in the management of metaplastic breast carcinoma

Background: Metaplastic breast carcinoma (MBC) accounts for &lt;5% of all breast malignancies. This entity represents a heterogenous group of tumors in which the adenocarcinomatous element is admixed with one or more neoplastic mesenchymal (spindle, squamous, chondroid, or osseous) elements. Patients typically present with large triple negative tumors and have a poor prognosis. The likelihood of lymph node (LN) involvement has been reported to be low in MBC patients. Due to the paucity of data, we undertook this study to explore the role of axillary ultrasound (US) and sentinel LN biopsy (SLNB) in the management of MBC.

Methods: With IRB approval, we retrospectively identified patients diagnosed with MBC from 2001–2011 from the surgical pathology database. Histopathology and imaging were reviewed. Demographic, treatment and outcome data were obtained by clinical chart review. Data were analyzed using JMP 9.0 software.

Results: We identified 41 women with MBC. Median age was 60 years (range 33–90). Histologic subtypes were spindle cell (46%), mixed adenocarcinoma and mesenchymal elements (20%), squamous cell (17%) chondroid/osseous (10%) and adenosquamous (7%). Tumor stage was T1 (24%), T2 (44%), T3 (12%) and T4 (20%). 26 patients (63%) were treated by mastectomy and 15 (37%) by wide excision. Of the 38 patients who underwent LN surgery (6 low-grade MBC, 32 intermediate/high-grade MBC), 10 (26%) were LN positive. All low-grade MBC patients were LN negative while 10 of 32 intermediate/high-grade MBC patients (31%) had LN metastasis. 22 patients had a preoperative axillary US. 14 patients had a negative axillary US and none had LN metastasis. 4 of 8 patients with suspicious axillary US findings had a preoperative axillary LN fine needle aspiration biopsy (FNAB) and 3 were positive for cancer. These patients proceeded directly to axillary LN dissection (ALND). 24 patients had a SLNB of whom one was SLN positive and underwent completion ALND. LN metastasis was associated with larger tumor size (p = 0.003), higher tumor grade (p = 0.04), angioinvasion (p = 0.07) and abnormal axillary US (p = 0.003). Surviving patients were followed for a mean (median) of 41 (30) months during which 13 (32%) recurred at a median of 6 months (IQR 3–17 months) and 11 (27%) subsequently died of disease. One SLN negative patient developed an axillary recurrence at 8 months, was successfully treated by ALND and is disease-free at 38 months. There were no axillary LN relapses after ALND.

Conclusions: For clinically node-negative MBC patients, our contemporary data series suggests the incidence of occult LN metastasis is sufficiently high to warrant LN staging especially for patients with intermediate and high-grade tumors. This can be accomplished in a minimally invasive fashion with reasonable accuracy (∼97%) with axillary US, FNAB of sonographically suspicious LNs, and SLNB for patients with negative axillary US or FNAB. Axillary LND should be performed for patients with clinically and/or FNAB-positive LN for enhanced disease control.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-01-22.