COMPLETE HYDROLYSIS OF STEROID CONJUGATES AND QUANTITATIVE EXTRACTION OF FREE STEROIDS FROM URINE

1967 ◽  
Vol 45 (2) ◽  
pp. 191-202 ◽  
Author(s):  
F. A. Vandenheuvel
Keyword(s):  
Simple Procedure ◽  
Helix Pomatia ◽  
Quantitative Extraction ◽  
Freeze Dried ◽  
Liquid Chromatographic Analysis ◽  
High Concentrations ◽  
Liquid Chromatographic ◽  
Chloroform Methanol ◽  
Hydrolysis Of ◽  
Steroid Conjugates

A simple procedure for the serial hydrolysis and extraction of 5-ml urine samples is described. The samples are incubated at pH 4.45 for 24 hours at 87 °C with high concentrations of β-glucuronidase and sulfatases from Helix pomatia. The incubated samples are freeze-dried and the residual solids are repeatedly extracted with a total of 15 ml of chloroform–methanol (1:2, v/v). The overall efficiency is over 99%. A method for the systematic estimation of urinary steroids based on the combined thin-layer and gas–liquid chromatographic analysis of total extracts is outlined.

scholarly journals The Effects of Microwave-Assisted Pretreatment and Cofermentation on Bioethanol Production from Elephant Grass

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Sefrinus Maria Dolfi Kolo ◽  
Deana Wahyuningrum ◽  
Rukman Hertadi
Keyword(s):  
Acid Hydrolysis ◽  
Hydrolysis Product ◽  
Pichia Stipitis ◽  
Pennisetum Purpureum ◽  
Bioethanol Production ◽  
Elephant Grass ◽  
Microwave Assisted ◽  
Liquid Chromatographic Analysis ◽  
High Concentrations ◽  
Liquid Chromatographic

The process of acid hydrolysis using conventional methods at high concentrations results in products having lower yields, and it needs a longer time of process; therefore, it becomes less effective. In this study, we analyzed the effects of microwave-assisted pretreatment and cofermentation on bioethanol production from elephant grass (Pennisetum purpureum). We used a combination of delignification techniques and acid hydrolysis by employing a microwave-assisted pretreatment method on elephant grass (Pennisetum purpureum) as a lignocellulosic material. This was followed by cofermentation with Saccharomyces cerevisiae ITB-R89 and Pichia stipitis ITB-R58 to produce bioethanol. The optimal sugar mixtures (fructose and xylose) of the hydrolysis product were subsequently converted into bioethanol by cofermentation with S. cerevisiae ITB-R89 and P. stipitis ITB-R58, carried out with varying concentrations of inoculum for 5 days (48 h) at 30°C and pH 4.5. The high-power liquid chromatographic analysis revealed that the optimal inoculum concentration capable of converting 76.15% of the sugar mixture substrate (glucose and xylose) to 10.79 g/L (34.74% yield) of bioethanol was 10% (v/v). The optimal rate of ethanol production was 0.45 g/L/d, corresponding to a fermentation efficiency of 69.48%.

Radioimmunoassay of 2-hydroxyestrone in urine

1994 ◽  
Vol 40 (1) ◽  
pp. 80-85 ◽  
Author(s):  
B J McGuinness ◽  
M J Power ◽  
P F Fottrell
Keyword(s):  
Breast Cancer ◽  
Acid Hydrolysis ◽  
Helix Pomatia ◽  
Enzyme Hydrolysis ◽  
Human Tissues ◽  
Catechol Estrogens ◽  
Urinary Steroids ◽  
High Concentrations ◽  
Urinary Steroid ◽  
Steroid Conjugates

Abstract Catechol estrogens such as 2-OH estrone are interesting estrogen metabolites formed in several human tissues and excreted in urine. We developed and thoroughly validated a radioimmunoassay for urinary 2-OH estrone that has several advantages over published RIAs. Because we developed a relatively specific antiserum, we did not include a preliminary chromatographic step to eliminate cross-reacting urinary steroids. We hydrolyzed urinary steroid conjugates with beta-glucuronidase from Helix pomatia because recoveries after acid hydrolysis were only 49.6% compared with 73.8% after enzyme hydrolysis. Published RIAs for urinary 2-OH estrone use acid hydrolysis. Our RIA measured 2-OH estrone independently of the volume of sample, and the detection limit was between 100 and 240 ng/L (10-24 pg per tube). The ED50 was 370 ng/L, and inter- and intraassay CVs for low, medium, and high concentrations were 22.5%, 22.8%, and 19.9%, and 17.4%, 14.3%, and 10.8%, respectively. Median concentrations measured in 14 controls and 33 postmenopausal patients with breast cancer were 0.96 and 1.55 micrograms/g creatinine, respectively, but there was considerable overlap between values from controls and patients.

Endothelin-like immunoreactivity in rat models of diabetes mellitus

1991 ◽  
Vol 130 (1) ◽  
pp. 123-127 ◽  
Author(s):  
K. Takahashi ◽  
K. Suda ◽  
H.-C. Lam ◽  
M. A. Ghatei ◽  
S. R. Bloom
Keyword(s):  
Diabetes Mellitus ◽  
Plasma Concentrations ◽  
Endothelin 1 ◽  
Patients With Diabetes ◽  
Liquid Chromatographic Analysis ◽  
High Concentrations ◽  
Endothelin 3 ◽  
Animal Models Of Diabetes ◽  
Liquid Chromatographic ◽  
Lung And Kidney

ABSTRACT The factors associated with high concentrations of circulating plasma immunoreactive endothelin in patients with diabetes mellitus are unknown. Plasma and tissue (lung and kidney) immunoreactive endothelin levels were therefore measured by radioimmunoassay in three animal models of diabetes mellitus: dexamethasone-treated rats (2 mg/kg per day for 12 days), streptozotocin-treated rats (100 mg/kg, 4 days before being killed) and rats treated with both dexamethasone and streptozotocin. Plasma concentrations of immunoreactive endothelin in the dexamethasone-treated rats (3·13±0·28 pmol/l, mean ± s.e.m., n = 15) were significantly (P < 0·005) higher than those in controls (1·33±0·18 pmol/l, n = 15), while plasma concentrations of immunoreactive endothelin in streptozotocin-treated rats (n = 8) and rats treated with both dexamethasone and streptozotocin (n= 14) were undetectable (< 0·5 pmol/l). Fast protein liquid chromatographic analysis of the plasma immunoreactive endothelin of dexamethasone-treated rats showed four peaks: one in the void volume, one eluting before endothelin-3, one eluting after endothelin-3 and before endothelin-1 and one eluting in a position identical with that of endothelin-1. Pulmonary concentrations of immunoreactive endothelin in the three groups of rats with diabetes mellitus were lower (P < 0·005) but no significant change was found in renal immunoreactive endothelin. These findings indicate that short-term dexamethasone treatment increases plasma levels of immunoreactive endothelin while streptozotocin treatment decreases them. Thus, multiple factors may influence plasma concentrations of immunoreactive endothelin in diabetes mellitus. Journal of Endocrinology (1991) 130, 123–127

scholarly journals A comparison of mycotoxin contamination of premium and grocery brands of pelleted cat food in South Africa

2017 ◽  
Vol 88 ◽  
Author(s):  
Sanil D. Singh ◽  
Sooraj Baijnath ◽  
Anil A. Chuturgoon
Keyword(s):  
Chromatographic Analysis ◽  
High Performance ◽  
High Performance Liquid Chromatographic ◽  
Pathological Changes ◽  
Pet Owners ◽  
Lack Of Information ◽  
Liquid Chromatographic Analysis ◽  
High Concentrations ◽  
Liquid Chromatographic ◽  
Feed Samples

Contamination with mycotoxins is of concern to pet owners and veterinary practitioners owing to their ability to cause disease and exacerbate the pathological changes associated with other diseases. Currently, there is a lack of information regarding the mycotoxin content of common premium brand (PB) and grocery brand (GB) cat feeds. Therefore, we undertook to determine the mycobiota content of feed samples, from both categories (n = 6 each), and measured the levels of aflatoxin (AF), fumonisin (FB), ochratoxin A (OTA) and zearalenone (ZEA) by high performance liquid chromatographic analysis. There were high concentrations of mycotoxins in both categories of feed, regardless of the notion that PBs are of a higher quality. The concentration of these toxins may contribute to the development of related pathologies in felines.

Sign in / Sign up

Export Citation Format

Share Document