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PHƯƠNG PHÁP NHANH CHIẾT VÀ TINH LỌC TOÀN BỘ LIPID Các nghiên cứu về phân hủy lipid trong cá đông lạnh đã dẫn đến việc phát triển một phương pháp đơn giản và nhanh chóng để chiết xuất và tinh lọc lipid từ các vật liệu sinh học. Toàn bộ quy trình có thể được thực hiện trong khoảng 10 phút; nó hiệu quả, có thể tái sản xuất và không gây ra các thao tác gây hại. Mô ướt được đồng hóa với hỗn hợp chloroform và methanol theo tỷ lệ đảm bảo hệ thống tạo thành hòa tan với nước trong mô. Việc pha loãng với chloroform và nước tách đồng hóa thành hai lớp, lớp chloroform chứa tất cả các lipid và lớp methanolic chứa tất cả các phi lipid. Một chiết xuất lipid tinh khiết được thu được chỉ bằng cách cô lập lớp chloroform. Phương pháp này đã được áp dụng cho cơ cá và có thể dễ dàng điều chỉnh để sử dụng với các mô khác.
Canadian Science Publishing - Tập 37 Số 1 - Trang 911-917 - 1959
#Lipid #Phân hủy lipid #Chiết xuất lipid #Tinh lọc lipid #Cá đông lạnh #Mô sinh học
MỘT PHƯƠNG PHÁP NHANH CHÓNG ĐỂ CHIẾT XUẤT VÀ TINH CHẾ TỔNG LIPID Nghiên cứu sự phân hủy lipid trong cá đông lạnh đã dẫn đến việc phát triển một phương pháp đơn giản và nhanh chóng để chiết xuất và tinh chế lipid từ các vật liệu sinh học. Toàn bộ quy trình có thể được thực hiện trong khoảng 10 phút; nó hiệu quả, có thể tái lập và không có sự thao tác gây hại. Mô ướt được đồng nhất hóa với hỗn hợp chloroform và methanol theo tỷ lệ sao cho hệ thống tan được hình thành với nước trong mô. Sau khi pha loãng với chloroform và nước, dịch đồng nhất được phân tách thành hai lớp, lớp chloroform chứa toàn bộ lipid và lớp methanol chứa tất cả các hợp chất không phải là lipid. Một chiết xuất lipid tinh khiết được thu nhận chỉ đơn giản bằng cách tách lớp chloroform. Phương pháp này đã được áp dụng cho cơ cá và có thể dễ dàng thích nghi để sử dụng với các mô khác.
Canadian Science Publishing - Tập 37 Số 8 - Trang 911-917 - 1959
#Lipid #chiết xuất #tinh chế #cá đông lạnh #chloroform #methanol #hệ tan #phương pháp nhanh chóng #vật liệu sinh học #nghiên cứu phân hủy lipid.
A COMPARISON OF THE EFFECTIVENESS OF INTRAVENOUS, AS OPPOSED TO SUBCUTANEOUS, INJECTION OF PROGESTERONE FOR THE INDUCTION OF ESTROUS BEHAVIOR IN THE RAT
Canadian Science Publishing - Tập 38 Số 11 - Trang 1381-1383 - 1960
EFFECT OF COLD EXPOSURE ON RESPIRATORY C<sup>14</sup>O<sub>2</sub>PRODUCTION DURING INFUSION OF ALBUMIN-BOUND PALMITATE-1-C<sup>14</sup>IN WHITE RATS Albumin palmitate-1-C14 complex was infused at a constant rate through a carotid cannula (inserted 5–7 days earlier) into otherwise intact non-fasted rats in environments at 30° or 6 °C, after acclimation to 30° or 6 °C. At 6 °C, both warm- and cold-acclimated rats similarly exhaled as CI4 O2 a larger proportion of the injected C14 and gave lower terminal amounts of C14 in the extracted free fatty acids (F.F.A.) of plasma than at 30 °C. These results indicate that plasma F.F.A. serve as substrate for cold-thermogenesis. Also, increased turnover and oxidation of F.F.A. are not always inversely related to carbohydrate utilization but may be increased under conditions which result in concomitantly higher rates of turnover and oxidation of glucose.
Canadian Science Publishing - Tập 39 Số 2 - Trang 219-224 - 1961
A MODIFIED SPECTROPHOTOMETRIC DETERMINATION OF CHYMOTRYPSIN, TRYPSIN, AND THROMBIN The spectrophotometric procedure proposed by Schwert and Takenaka for the assay of chymotrypsin and trypsin has been modified and extended to include the application to N-benzoyl-L-tyrosine ethyl ester and α-p-toluenesulphonyl-L-arginine methyl ester. The greater degree of sensitivity and specificity thus achieved permits the determination of traces of chymotrypsin in the presence of relatively large amounts of trypsin and vice versa. A similar spectrophotometric procedure for the assay of thrombin is described.
Canadian Science Publishing - Tập 37 Số 12 - Trang 1393-1399 - 1959
AN AUSCULTATORY TECHNIQUE FOR MEASURING THE DIGITAL BLOOD PRESSURE The digital systolic and diastolic blood pressures in human subjects were estimated by means of an auscultatory technique similar to the clinical auscultatory method of measuring brachial blood pressure. The stethoscope was modified by substituting a digital plethysmograph (into which the finger was sealed) for the usual diaphragm. Korotkoff sounds were heard through the stethoscope as a pneumatic cuff around the base of the finger was deflated from a suprasystolic level. In comparison of this method with the plethysmographic method of measuring digital systolic pressure and with a method involving direct observation of resumption of blood flow in capillary loops of the nailfold as an end point when a cuff on the finger was deflated from a supra-systolic level, it was found that the first sound is as reliable an index of systolic pressure as those used in the other methods.
Canadian Science Publishing - Tập 36 Số 9 - Trang 883-888 - 1958
THE ORIGIN, METABOLISM, AND STRUCTURE OF NORMAL HUMAN SERUM LIPOPROTEINS The main fractions obtained by ultracentrifugal separation of normal human serum lipoproteins form distinct classes. On the high-density side (d > 1.063) HDL1 , HDL2 , and HDL3 ; on the low-density side: LDL1 , LDL2 , and chylomicra are represented by particles of increasing density, lipid content, and diameter, the latter ranging from about 100 Å (HDL3 ) to about 15.000 Å (largest chylomicron).Distinctions between classes are evidenced by the action of solvents, the analysis of the N-terminal amino acids of peptides and immunochemical and metabolic properties.High-density lipoproteins (HDL) and low-density lipoproteins (LDL) form distinct groups displaying dissimilarities on the basis of many criteria. There can be little doubt that the origin, structure, and functions of the two groups are different. Among the LDL, LDL2 , and LDL1 are both very similar and complex, LDL2 appearing to be a precursor of LDL1 . HDL on the other hand may be partially derived from the chylomicra as a result of intravascular lipoprotein action upon some of these transient, very low-density lipoproteins with which they share characteristic peptides.Since no satisfactory structural model for the lipoproteins has yet been published, it was the purpose of this paper to re-examine all pertinent data and to present new speculations regarding these structures.It could be demonstrated that the lipoproteins on the low-density side are particles characterized by a protein coverage which is uniform over their extensive dimensional range and which corresponds to 36 A2 per amino acid residue. LDL1 , the smallest of the group and the most abundant of the normal human serum lipoproteins, appears to consist of a single monolayer of lipids bearing adsorbed protein and surrounding a central core of occluded water. The general configuration of the adsorbed protein is still unknown. It is demonstrated that our present knowledge of the configuration of protein and synthetic polypeptide monolayers, most of which is derived from experiments with the film balance at air–water and petroleum ether – water (so-called oil–water) interface, cannot apply to these lipoproteins since there exists a considerable difference in physical and ionic topography between the experimental "oil–water" interface and the interface involved in lipoproteins.Part of the demonstration consists of the structural analysis of the lipid molecules involved. Diagrams representing these molecules, which are exact as to interatomic distances and bond angles are presented and used to explain the important phenomenon of sterol–phospholipid association. The latter is expected to play a considerable role in LDL1 (and presumably in the external lipid layer of LDL2 and chylomicra) where phospholipids and cholesterol (free and bound) represent 90% of the total molecular species with cholesterol (free and bound) accounting for two-thirds of them. By virtue of their associative properties, such molecules must exist in organized arrays conferring a directive influence to the lipid film on the configuration of the adsorbed protein. This should be quite different from the dispersive action of the disorganized petroleum ether layer in the so-called "oil–water" interface which induces partial random uncoiling of the protein chains.A demonstration of the method used in studying lipoprotein films by the use of diagrams is given. Its application to the cholesterol monolayer yielded for the limiting area a value in excellent agreement with that obtained with the film balance.
Canadian Science Publishing - Tập 40 Số 1 - Trang 1299-1326 - 1962
ISOLATION AND IDENTIFICATION OF 11-KETOTESTOSTERONE IN SALMON PLASMA A new blood steroid, 11-ketotestosterone, has been isolated from postspawned male sockeye salmon. The steroid was identified by chromatography, infrared spectra, chemical transformation, and synthesis. This steroid is present at a concentration of 12 μg/100 ml of plasma and probably was reported as corticosterone by other investigators. Evidence is presented in support of the occurrence of corticosterone at a very low concentration in salmon plasma. The concentrations of cortisol, cortisone, corticosterone, and total Porter–Silber positive steroids were determined in large plasma samples taken from postspawned fish of both sexes.
Canadian Science Publishing - Tập 38 Số 1 - Trang 1053-1057 - 1960
THE ROLE OF LONG-RANGE FORCES IN THE COHESION OF LIPOPROTEINS The various long-range forces which are effective between molecules in their electronic ground states are examined. Orders of magnitude are given for those forces which should occur in the interaction of lipide and protein chains. It is found that electrostatic forces should be responsible for bringing and holding together protein and lipide components, but London – Van der Waals dispersion forces are probably of paramount importance in maintaining the lipide chains together in micelles or double layers.Special attention is drawn to the dispersion forces and to the conditions under which these forces are locally additive; one can calculate accurate values of the dispersion energy of interaction between saturated hydrocarbon chains at short distances (a few angstroms apart) by adding all the bond–bond interactions. A general expression is given for the dispersion energy between two parallel and opposed chains built out of identical units, and numerical values are given for the case of closely packed hydrocarbon chains.The total attraction energy is extremely sensitive to the intermolecular distance. The role of this "distance-specificity" in interactions involving unsaturated fatty acid chains and its contribution to the stability of lipoproteins is briefly examined.
Canadian Science Publishing - Tập 40 Số 9 - Trang 1287-1298 - 1962
PAROTID SECRETION OF IODIDE Parotid juice from normal human subjects was collected by means of suction cups over the parotid papillae. The iodide content of the secretion was determined at various flow rates with and without the oral administration of potassium iodide, ammonium thiocyanate, and methimazole (Tapazole, Lilly), as these drugs are known to influence iodide metabolism in the thyroid gland. An inverse curvilinear relationship was found between the concentration of iodide and the rate of parotid secretion. Potassium iodide by mouth increased the concentration of parotid juice iodide in the same proportion as the increase in blood level of iodide. The amount of iodide secreted by the parotid glands was depressed by the administration of thiocyanate but was not influenced by the administration of methimazole.
Canadian Science Publishing - Tập 34 Số 4 - Trang 683-688 - 1956
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