Chip for dielectrophoretic microbial capture, separation and detection II: experimental study

In our previous paper we have modelled a dielectrophoretic force (DEP) and cell particle behavior in a microfluidic channel (Weber MUet al2023 Chip for dielectrophoretic microbial capture, separation and detection I: theoretical basis of electrode designNanotechnologythis issue). Here we test and confirm the results of our modeling work by experimentally validating the theoretical design constraints of the ring electrode architecture. We have compared and tested the geometry and particle capture and separation performance of the two separate electrode designs (the ring and dot electrode structures) by investigating bacterial motion in response to the applied electric field. We have quantitatively evaluated the electroosmosis (EO) to positive DEP (PDEP) transition in both electrode designs and explained the differences in capture efficiency of the ring and dot electrode systems. The ring structure shows 99% efficiency of bacterial capture both for PDEP and for EO. Moreover, the ring structure shows an over 200 faster bacterial response to the electric field. We have also established that the ring electrode architecture, with appropriate structure periodicity and spacing, results in efficient capture and separation of microbial cells. We have identified several critical design constraints that are required to achieve high efficiency bacterial capture. We have established that the spacing between consecutive DEP traps smaller than the length of the depletion zone will ensure that the DEP force dominates bacterial motion over motility and Brownian motion.

Chip for dielectrophoretic microbial capture, separation and detection I: theoretical basis of electrode design

We model the dielectrophoretic response ofE. colibacterial cells and red blood cells, upon exposure to an electric field. We model the separation, capture, and release mechanisms under flow conditions in a microfluidic channel and show under which conditions efficient separation of different cell types occurs. The modelling work is aimed to guide the separation electrode architecture and design for experimental validation of the model. The dielectrophoretic force is affected both by the geometry of the electrodes (the gradient of the electric field), the Re{CM(ω)} factor, and the permittivity of the medium ϵ_m. Our modelling makes testable predictions and shows that designing the electrode structure to ensure structure periodicity with spacing between consecutive traps smaller than the length of the depletion zone ensures efficient capture and separation. Such electrode system has higher capture and separation efficiency than systems with the established circular electrode architecture. The simulated, modelled microfluidic design allows for the separated bacteria, concentrated by dedicated dielectrophoretic regions, to be subsequently detected using label-free functionalized nanowire sensors. The experimental validation of the modelling work presented here and the validation of the theoretical design constraints of the chip electrode architecture is presented in the companion paper in the same issue (Weber MUet al2022 Chip for dielectrophoretic Microbial Capture, Separation and Detection II: Experimental Study).

[The beta-hCG subunit, CA 125 and CA 19-9 antigen in the women with non-trophoblastic malignancy of genital tract]

OBJECTIVES

The aim of this study was preoperative estimation of serum level glicoprotein--CA 125, CA 19-9 and beta-hCG in ovarian tumors and comparison obtained values in groups divided according to postoperative pathologic examination.

MATERIALS AND METHODS

In every patients with ovarian tumors before surgery the level above mentioned antigens was evaluated and compared in following groups: malignant, non-malignant and controls. In control group cut-off values was estimated.

RESULTS

The levels of all investigated glycoproteins were significantly higher in malignant group comparing to benign and controls. The test differentiating non-malignant from malignant tumors was accepted as positive if at least one from markers level was elevated. Specificity of the test was 70%, sensitivity--94%, positive prognostic value--74%, negative prognostic value--94%. In the selected subgroups from non-malignant tumors the serum level of all glycoproteins was surprisingly high.

CONCLUSIONS

Preoperative estimation of CA 125, CA 19-9 and beta-hCG subunit in ovarian tumors permits--at negative result--with probability 93% to qualify tumor as non-malignant and sensitivity of test is 94%.

[The beta-hCG subunit, CA 125 and CA 19-9 antigen in the women with non-trophoblastic malignancy of genital tract. Endometrial cancer]

OBJECTIVES

There are few conflicting reports in regards of markers appearing in the patients with endometrial cancer. The aim of this study was to evaluate the serum levels: CA 125 antigen, CA 19-9 antigen and beta-hCG subunit in this group of patients and comparing obtained results with normal controls.

MATERIALS AND METHODS

In both groups--with endometrial cancer (n = 43)- and controls-(n = 214)--CA125 antigen, CA 19-9 antigen and beta-hCG subunit the serum level were determined two = site of immunometric method. The differences of the means, correlations, specificity, sensitivity, positive predictive value, negative predictive value and efficiency were calculated.

RESULTS

The women with endometrial cancer exhibited the significantly higher level of all antigens. The positive correlation between CA 125 serum level and staging and grading and between beta-hCG subunit and endometrial cancer staging was found. The positive test had: specificity--62%, sensitivity--93%, positive predictive value--66%, negative predictive value--92% and efficiency--92.5%.

CONCLUSIONS

In the women with endometrial cancer appears non-specific antigens characteristic for the müllerian duct derivatives tissue, exhibiting Lewis blood group antigen and involving in membrane cell structures in normal and cancer cells. The level of these antigens correlates with grading and staging of the neoplasms.

Radical hysterectomy for IB cervical cancer in a patient with aorto-femoral transposition

We present a cervical cancer case in stage IB, according to FIGO classification, treated with radical hysterectomy and pelvic lymphadenectomy. The 48-year-old patient had 4 years previously undergone a Y aorto-bifemoral Dallon transposition as a result of Leriche's syndrome. During the routine investigation invasive cervical cancer was diagnosed. She had radical hysterectomy of Piver III type and partial pelvic lymphadectomy. Radical hysterectomy caused no technical trouble. Pelvic lymphadenectomy was only partially possible because of hard connective tissue around the artificial vessels. This scarred region made safe preparation of the total pelvic lymphatic system impossible.

[Giant placental angioma with polyhydramnios, high level of alpha-fetoprotein and neonatal congenital lactic acidosis]

Placental tumors are rare in pregnancy. They cause nonspecific complications such as polyhydramnios, fetal anemia, fetal thrombocytopenia and cardiac decompensation with non-immunological hydrops fetalis. In the presented case a very large placental hemangioma was connected with polyhydramnios, premature delivery, fetal anemia and thrombocytopenia, maternal serum alpha fetoprotein elevation and congenital lactic acidosis. After delivery a severe state of the newborn was caused by oligovolemic shock. In the course of the disease the neonatal state steadily deteriorated mainly because of sepsis, cerebral hemorrhage and metabolic acidosis despite adequate therapy. The organic acids assessment in the blood serum of a newborn child showed a very strong signal of lactic acid and an increase in parahydroksyfenylolactic acid. Postmortal examination confirmed prematurity, respiratory distress syndrome, sepsis and cerebral hemorrhage. These symptoms probably resulted from the presence of a placental tumor of considerable size of 12 cm and congenital lactic acidosis, which to our knowledge, have not been described in the available literature until now. In conclusion it should be underlined, that there exists difficult to explain relationship between the presence of a placental haemangioma and severe metabolic changes resulting in high mortality and morbidity of the newborn.

[A case of extended hysterectomy in stage IB-1 cervical cancer after aorto-bifemoral reconstruction]

We describe a cervical cancer case stage IB-1 according to FIGO classification surgically treated with extended hysterectomy and lymphadenectomy. The patient was four years after aorto-femoral Dallon bypass on account of Leriche syndrome and from this time she was treated with oral anticoagulant therapy. During the routine diagnostic investigations the invasive cervical cancer IB-1 was diagnosed. According to the oncological protocol she has had extended hysterectomy Piver III type and partial pelvic lymphadenectomy. Extended hysterectomy did not cause technical troubles. Pelvic lymphadenectomy was only partially possible to realizing. Compact connective tissue around the artificial vessels did not permit safe preparation of pelvic lymphatic system.

[Beta subunit of human chorionic gonadotropin, CA 125 antigen and CA 19-9 antigen with non-trophoblastic malignancy of genital tract. Vulval cancer]

Our investigations embraced the group of patients with vulval cancer before surgical treatment (n = 10). We measured in serum of blood the level of the total human chorionic gonadotrophin hCG, beta subunit of human Chorionic Gonadotrophin, CA 125 and CA 19-9 antigen. We ascertained significant elevation the beta subunit of hCG level in the group of women with neoplasms in comparison with control group (n = 96) and significant positive correlation between beta subunit level and degree of cancer cells maturity (r = 0.66, p < 0.05). We also ascertained strong positive correlation among beta subunit of hCG and CA 19-9 antigen level in the serum of the patients with vulval cancer (r = 0.55 and p < 0.05).

Hemodynamic effects of intravenous hydralazine in pregnant women with severe hypertension

The hemodynamic changes after intravenous administration of hydralazine were assessed using M-mode echocardiography in 13 pregnant patients with severe hypertension. The patients were divided into two groups: eight who had preeclampsia (group 1) and five who had essential hypertension and/or superimposed preeclampsia (group 2). Patients in group 1 had significantly lower pretreatment cardiac indexes and higher systemic vascular resistances (P less than .01) than did patients of group 2, despite similar mean blood pressure values. Thirty minutes after intravenous administration of 12.5 mg hydralazine, a significant decrease in mean arterial pressure (21%) and systemic vascular resistance (41%) and also a significant increase in heart rate (22%) and cardiac index (33%) were observed in group 1. The hemodynamic response in group 2 was attenuated; the mean arterial pressure and systemic vascular resistance fell by an average of 11 and 13%, respectively. The post-hydralazine percent changes in mean blood pressure for the total patient population did not correlate with the initial values of blood pressure (r = .091). In contrast, the percent reduction in systemic vascular resistance after administration of hydralazine inversely correlated with the control values of vascular resistance (r = -.742). These findings indicate that cardiovascular response to acute hydralazine administration is related to the baseline hemodynamic setting. M-mode echocardiography seems to be a reliable method for comprehensive analysis of cardiovascular effects of pharmacologic intervention in pregnant women with hypertension.

Left ventricular function in preeclamptic patients: an echocardiographic study

To examine left ventricular function in pregnancy complicated by preeclampsia, echocardiographic dimensions and left ventricular performance indices were determined in 42 preeclamptic patients, 25 normotensive third-trimester patients, and 25 nonpregnant patients. The performance of the left ventricle in normal third-trimester pregnant patients was unchanged as compared to that in nonpregnant patients. Three patients (7%) in the preeclamptic group had diminished values of echocardiographic contractility indices. However, in only one of these patients were there clinical signs of left heart failure; two other patients had latent myocardial dysfunction. Our conclusion is that left ventricular function in most preeclamptic patients is well preserved despite significant volume and pressure overload.

Echocardiographic estimation of hemodynamics in hypertensive pregnancy

M-mode echocardiography and indirect blood pressure measurements were used to examine hemodynamics in three groups of pregnant patients: 19 who were preeclamptic, nine who had essential hypertension, and 19 who were normotensive. The preeclamptic patients had significantly lower heart rate (68.4 versus 74.7 beats/min, p less than 0.05), stroke volume (89 versus 101 ml; p less than 0.02), and cardiac index (5.9 versus 7.5 L/min/sq m; p less than 0.001) than those of control patients matched for age, parity, and gestational age. The mean values for heart rate, stroke volume, and cardiac index in patients with essential hypertension were not significantly different from those in the control group; however, the former had widely varying individual hemodynamic patterns. The significant inverse correlation was found between cardiac index and mean blood pressure (r = -0.602) in preeclamptic patients. There was a positive correlation between maternal cardiac index and infant birth weight (r = 0.813) and also inverse relationship between systemic vascular resistance and infant birth weight (r = -0.890) in this group. Possible explanations for these findings are discussed.