Nanostructured Metal Oxide-Based Electrochemical Biosensors in Medical Diagnosis

Nanostructured metal oxides (NMOs) provide electrical properties such as high surface-to-volume ratio, reaction activity, and good adsorption strength. Furthermore, they serve as a conductive substrate for the immobilization of biomolecules, exhibiting notable biological activity. Capitalizing on these characteristics, they find utility in the development of various electrochemical biosensing devices, elevating the sensitivity and selectivity of such diagnostic platforms. In this review, different types of NMOs, including zinc oxide (ZnO), titanium dioxide (TiO2), iron (II, III) oxide (Fe3O4), nickel oxide (NiO), and copper oxide (CuO); their synthesis methods; and how they can be integrated into biosensors used for medical diagnosis are examined. It also includes a detailed table for the last 10 years covering the morphologies, analysis techniques, analytes, and analytical performances of electrochemical biosensors developed for medical diagnosis.

Novel Approaches to Enzyme-Based Electrochemical Nanobiosensors

Electrochemistry is a genuinely interdisciplinary science that may be used in various physical, chemical, and biological domains. Moreover, using biosensors to quantify biological or biochemical processes is critical in medical, biological, and biotechnological applications. Nowadays, there are several electrochemical biosensors for various healthcare applications, such as for the determination of glucose, lactate, catecholamines, nucleic acid, uric acid, and so on. Enzyme-based analytical techniques rely on detecting the co-substrate or, more precisely, the products of a catalyzed reaction. The glucose oxidase enzyme is generally used in enzyme-based biosensors to measure glucose in tears, blood, etc. Moreover, among all nanomaterials, carbon-based nanomaterials have generally been utilized thanks to the unique properties of carbon. The sensitivity can be up to pM levels using enzyme-based nanobiosensor, and these sensors are very selective, as all enzymes are specific for their substrates. Furthermore, enzyme-based biosensors frequently have fast reaction times, allowing for real-time monitoring and analyses. These biosensors, however, have several drawbacks. Changes in temperature, pH, and other environmental factors can influence the stability and activity of the enzymes, affecting the reliability and repeatability of the readings. Additionally, the cost of the enzymes and their immobilization onto appropriate transducer surfaces might be prohibitively expensive, impeding the large-scale commercialization and widespread use of biosensors. This review discusses the design, detection, and immobilization techniques for enzyme-based electrochemical nanobiosensors, and recent applications in enzyme-based electrochemical studies are evaluated and tabulated.

Buckwheat conservation as hay or silage: agronomic evaluation, nutritive value, conservation quality, and intake by lactating dairy goats

Buckwheat was conserved either as silage at two dry matter (DM) levels attained with (wilted silage (WS), 313 g/kg) and without wilting (direct cut silage (DS), 171 g/kg) or as hay (856 g/kg) and was included in the isonitrogenous and isocaloric total mixed ration (TMR) of four groups of six Saanen goats each at the rate of 200 g/kg DM. Ensiling buckwheat at low DM led to a poorly fermented silage with higher ammonia-N and butyric acid contents and extensive growth of enterobacteria and mold-yeast than WS. The DM recovery of DS was lower than that of WS. The total phenol (TP) content of buckwheat was also preserved more efficiently in hay than in DS. The nutritive value of hay was higher than that of the silages because hay had less fiber contents but more non-fiber carbohydrates and total digestible nutrients. The decrease in nutritive value in buckwheat silages, in particular for DS, increased the nutrient intensity in the concentrated feed. The DM intake of goats fed DS TMR tended to be lower (P=0.09) than that of the goats fed WS TMR in the first week of the experiment, but the goats quickly adapted to the poorly fermented silage and did not reduce their overall DM intake. The DS, WS, and hay TMRs did not affect fat corrected milk yield but increased the milk TPs compared to a TMR with legume-grass hay. It was concluded that buckwheat hay and silages are well accepted by dairy goats, but the DM content of buckwheat at ensiling may require over 330 g/kg for producing well-fermented silages.

Biomass yield and feeding value of rye, triticale, and wheat straw produced under a dual-purpose management system

Dual-purpose management of winter cereals for grazing and grain production provides highly nutritive forage for ruminants in the spring and may positively affect straw feeding value. A 2-yr study investigated the effect of spring defoliation of triticale, wheat, and rye at the tillering and stem elongation stages on total biomass, grain yields, and straw quality. Furthermore, straws of spring-defoliated and undefoliated (control) cereal crops were evaluated for nutritional value and voluntary intake as a means of assessing the efficiency of dual-purpose management systems from the winter feeding context as well. The feeding study consisted of 9 total mixed rations (TMR), each containing 35% triticale, rye, or wheat straw obtained under 3 spring-defoliation regimens. The TMR were individually fed to fifty-four 1-yr-old Anatolian Merino ewes for 28 d. Defoliation of the crops at tillering did not affect the total biomass production or grain yields. However, biomass and grain yields were reduced ( < 0.01) by 55 and 52%, respectively, in crops defoliated at stem elongation. Straw of spring-defoliated cereals had less NDF and ADF concentrations ( < 0.01) but greater CP ( < 0.01), nonfiber carbohydrates ( < 0.01), and ME concentrations ( < 0.01) compared with straw from undefoliated crops. The increase in the nutritive value of straw led to greater nutrient digestion ( < 0.01) and intake of DM and OM of ewes ( < 0.01). However, sheep live weight gain did not differ among treatments ( > 0.77). This study indicated that straw feeding value and digestibility can be increased through spring defoliation.

Intravenous albumin versus hydroxyethyl starch for the prevention of ovarian hyperstimulation in an in-vitro fertilization programme: a prospective randomized placebo controlled study

A prospective randomized placebo controlled clinical trial was carried out on 250 patients (cycles) considered at risk of developing OHSS in an IVF programme. Criteria for inclusion were: estradiol value of more than 3000 pg/ml or the presence of more than 20 follicles on the day of hCG administration. Patients were randomized by using a random table to receive either 20% human albumin 50 ml (n: 82); 6% hydroxyethyl starch (200/0.5) 500 ml (n: 85) or a placebo of 500 ml 0.9% NaCl solution (n: 83) over 30 min during oocyte collection. Groups were similar with respect to patients' age, estradiol levels on hCG day, body mass index, number of oocytes retrieved, number of embryos transferred and pregnancies (P>0.05). There was no severe OHSS in patients who received albumin and HES while four patients who received placebo developed severe OHSS. On the other hand moderate OHSS was encountered in four patients in the albumin group; five patients receiving HES; and 12 patients receiving placebo. There was a statistically significant difference in the incidence of moderate, severe and overall OHSS among groups (P values of <0.05, <0.05, and <0.01, respectively). Both HES and albumin significantly reduced the incidence of moderate, severe and overall incidence of OHSS. It is concluded that hydroxyethyl starch is a cheaper and safer alternative to Human Albumin in OHSS prevention.

Increasing the daily dose of recombinant follicle stimulating hormone (Puregon) does not compensate for the age-related decline in retrievable oocytes after ovarian stimulation

A prospective, randomized, double-blind, multicentre (n = 6) study was conducted to compare the influence of either a 150 or 250 IU daily fixed-dose regimen of recombinant follicle stimulating hormone (FSH, Puregon) on the number of oocytes retrieved and the total dose used in down-regulated women between 30 and 39 years of age undergoing ovarian stimulation. In all, 138 women were treated with recombinant FSH, 67 with 150 IU and 71 with 250 IU. The number of oocytes retrieved in the low-dose group was 9.1 compared to 10.6 in the high-dose group (not significant). In the 30-33 years of age class receiving the 250 IU dose, a surplus of 4.2 oocytes (14.8 versus 10.6) was found, whereas in the 37-39 age class nearly one oocyte more was retrieved in the 150 IU group (8.1 versus 7.4). The total dose used to reach the criterion for human chorionic gonadotrophin (HCG) administration was 1727 IU for the women treated with 150 IU daily and 2701 IU for the 250 IU treated women (P < 0. 001). No significant relationships were found between serum FSH concentrations as obtained in the early follicular phase and the number of oocytes collected, or the total dose. It is concluded that in women between 30 and 39 years of age, the decline in number of oocytes retrieved with increasing age cannot be overcome by augmenting the daily dose of recombinant FSH from 150 to 250 IU.

Intravenous albumin prevents moderate-severe ovarian hyperstimulation in in-vitro fertilization patients: a prospective, randomized and controlled study

OBJECTIVE

To assess the effectiveness of intravenous administration of albumin in prevention of ovarian hyperstimulation syndrome (OHSS) in patients of an in-vitro fertilization program.

STUDY DESIGN

Prospective randomized study. Patients with hCG day E2 levels are 11010 pmol/l (3000 pg/ml) or more were recruited into two groups. Group A (n = 27) received 10 g 20%, 50 ml human albumin infusion before oocyte pick-up and no medication was administered in Group B (n = 28).

RESULTS

Patients were similar in terms of cycle characteristics. No moderate-severe OHSS developed in Group A whereas one severe OHSS case and four moderate OHSS cases developed in Group B. Statistical analysis revealed a significant (P < 0.05) protection in albumin treated group.

CONCLUSION

Human albumin proves effectiveness in prevention of moderate-severe OHSS.

Demographic and epidemiologic features of female adolescents in Turkey

OBJECTIVES

To determine the average menarcheal age and menstrual cycle pattern, prevalence of dysmenorrhea, frequency of smoking, alcohol and drug use, sexual education level, and the gynecologic problems in female adolescents in Turkey.

METHODS

A questionnaire consisting of 43 questions were given to 13,665 high school girls between the ages 13-18 years.

RESULTS

The results showed that average menarcheal age was 13.28 +/- 1.09 years and 77.8% of the girls had menstrual cycles between 20-35 days; 10,688 (78.1%) of the girls complained about pain during their menstruation and 25.6% frequently missed school for this reason. That notwithstanding, only 0.4% of the adolescents with dysmenorrhea had sought medical consultation. Out of 13,665 girls, 19.7% smoked cigarettes, 14.9% used alcohol, and 0.63% used other drugs. Although 50.8% of the students believed that their knowledge about sexuality was adequate, on evaluating the results, this was not confirmed. Girlfriends were found to be the most important source of sexual knowledge. The study indicated that 88.8% of the girls wanted to have sexual education at schools and 60.5% of those preferred to take such a lecture together with boys. The study also revealed that 10.5% of the girls previously consulted a gynecologist and menstrual disorders (26.1%) and dysmenorrhea (23.4%) were the most common complaints. The results showed that 68.7% of the girls preferred a woman gynecologist and 66.3% wanted to be alone with the doctor during examination.

CONCLUSION

We provided data about demographic and epidemiologic features of Turkish female adolescents.