Purification and characteristics of an endogenous alpha-amylase inhibitor from barley kernels

An inhibitor of malted barley (Hordeum vulgare cv Conquest) α-amylase II was purified 125-fold from a crude extract of barley kernels by (NH₄)₂SO₄ fractionation, ion exchange chromatography on DEAE-Sephacel, and gel filtration on Bio-Gel P 60. The inhibitor was a protein with an approximate molecular weight of 20,000 daltons and an isoelectric point of 7.3. The protein was homogeneous, as assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Amino acid analysis indicated the presence of about 9 half-cystine residues per mole. The neutral isoelectric point of the inhibitor suggested that some of the apparently acidic residues (glutamic and aspartic) existed in the amide form. The first twenty N-terminal amino acids were sequenced. Some homology appeared to exist between the α-amylase II inhibitor and trypsin inhibitor from barley. Complex formation between α-amylase II and the inhibitor was detected by the appearance of a new molecular weight species after gel filtration on Bio-Gel P 100. Enzyme and inhibitor had to be preincubated for 5 min, prior to assaying for enzyme activity before maximum inhibition was attained. Inhibition increased at higher pH values. At pH 5.5, an approximately 1100 molar excess of inhibitor over α-amylase II produced 40% inhibition, whereas, at pH 8.0, a 1:1 molar ratio of inhibitor to enzyme produced the same degree of inhibition.     

Screening for cervical intraepithelial neoplasia in north east Scotland shows fall in incidence and mortality from invasive cancer with concomitant rise in preinvasive disease.

OBJECTIVE--To assess the effect of screening for cervical intraepithelial neoplasia on the incidence of and mortality from invasive squamous cell carcinoma of cervix in north east Scotland and to discover why cases of invasive cancer still occur. DESIGN--(a) Analysis of data on cases of cervical intraepithelial neoplasia obtained from the cytology data bank; (b) analysis of data on 612 women presenting with invasive squamous cancer during 1968-91, obtained from cancer registry and hospital records; (c) analysis of death rates obtained from the registrar general''s (Scotland) annual reports, the Information Services Division of the Home and Health Department (Scotland), and local records for 1974-91; (d) case-control studies on 282 cases of invasive cancer and 108 deaths which occurred in 1982-91. Cases were matched with two controls both for age and for having a negative smear test result at the time of presentation of the case. SETTING--North east Scotland (Grampian region, Orkney, and Shetland). SUBJECTS--Women (n = 306,608) who had had cervical smear tests between 1960 and 1991. RESULTS--There had been a substantial increase in cases of cervical intraepithelial neoplasia grade III since 1982. The incidence of invasive cancer has fallen since the start of screening in 1960, the fall occurring mainly in the well screened age group 40-69 years. There was a rise in women aged under 40 and over 70. Women with invasive disease seen between 1982 and 1991 mostly presented at stage I. Of these, half were unscreened, one third were poorly screened, 11% were found in retrospect to have had abnormal cells, 3% had recurrence of disease after treatment for cervical intraepithelial neoplasia grade III, and 3% were lost to follow up. Death rates had fallen, most noticeably in women aged 45-64, who had had the opportunity to be screened and rescreened. There was a disturbing rise in deaths among women under 45. Most deaths (65%) occurred in unscreened women. Case-control studies showed that the longer the time and absence of a smear test before presentation the higher was the risk of invasive cancer and of death. CONCLUSIONS--Screening has been effective in reducing the incidence of and mortality from cervical cancer in north east Scotland. Most cases and deaths occurred in unscreened women or in those who had had few smears at long intervals. An increase in cases of cervical intraepithelial neoplasia grade III in women screened for the first time occurred during 1982-91.     

Synthesis,characterization, and electrocatalytic behaviour of hydrothermally grown nanostructured La2O3 and La2O3/K-complex

Rare earth metals play a conspicuous role in magnetic resonance imaging (MRI) for detecting cancerous cells. The alkali metal potassium is a neurotransmitter in the sodium–potassium pump in biomedical sciences. This unique property of rare earth metals and potassium drew our attention to carry forward this study. Therefore, in this work, previously synthesized potassium (K) complexes formed by the reflux of 4-N,N-dimethylaminobenzoic acid (DBA) and potassium hydroxide in methanol, and named [(μ2–4-N,N-dimethylaminobenzoate-κO)(μ2–4-N,N-dimethylaminobenzoic acid-κO)(4-N,N-dimethylaminobenzoic acid-κO) potassium(I) coordination polymer)] were treated hydrothermally with La₂O₃ nanomaterials to obtain a nanohybrid La₂O₃/K-complex. After that, the K-complex was analyzed using single-crystal X-ray diffraction and ¹H and ¹³C NMR spectroscopy. In addition, the structural and morphological properties of the as-prepared nanostructured La₂O₃/K-complex were also characterized, which involved an investigation using X-ray diffraction (XRD)spectroscopy, Fourier transform infrared (FTIR) spectroscopy, atomic force spectroscopy (AFM), transmission electron microscopy (TEM), and energy dispersive X-ray (EDX) analysis. After this, the electrochemical redox behaviour of the synthesized nanohybrid material was studied using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Therefore, the results from these studies revealed that the as-prepared material was a La₂O₃/K-complex that has a promising future role in sensing various analytes, as it showed effective electrocatalytic behaviour.