摘要:

SUMMARYA number of arboviruses multiply in avian cells in tissue culture but fail to produce plaques in them when grown under an agar overlay. It has been shown that the addition of optimal amounts of DEAE dextran or of protamine enables some such viruses to form clear‐cut plaques to a high titre. The optimal doses do not inhibit plaque production by any arbovirus tested.

ISSN:0004-945X    

DOI:10.1038/icb.1963.19

出版商:Nature Publishing Group    

年代:1963

数据来源: WILEY

摘要:

SUMMARYA method of obtaining plaques with the virus of Murray Valley encephalitis (M.V.E.) is described. Although not as sensitive as mouse titration, the dose response relationship and the uniformity of the tissue culture system make it a satisfactory method for the assay of M.V.E. virus.

ISSN:0004-945X    

DOI:10.1038/icb.1963.20

出版商:Nature Publishing Group    

年代:1963

数据来源: WILEY

摘要:

SUMMARYA detailed examination of four modern manual methods for determining blood glucose is presented, and the effects of preservatives, anticoagulants, drugs and some reducing or interfering substances on the estimations are indicated. On grounds of precision, reliability and simplicity, the o‐amino‐toluene condensation method of Hultman and the glucose oxidase‐tolidine method of Watson are the most satisfactory and the Cu‐reduction method of Nelson the least satisfactory means of determining blood sugar in the clinical laboratory. Blood cells from normal and diabetic patients contain 65 p.c. (± 10 p.c.) of the glucose concentration found in the blood plasma of the same subject.

ISSN:0004-945X    

DOI:10.1038/icb.1963.21

出版商:Nature Publishing Group    

年代:1963

数据来源: WILEY

摘要:

SUMMARYIn the dogfishSqualus acanthias, touching or stroking the cornea or the skin around and rostral to the orbit caused the eye to flick towards the caudal margin. The response was strictly ipsilateral and was caused by a contraction of the external rectus muscle. The reflex latency determined from the oscillographic display of strain gauge recordings was 24·3, ± 1·1 msecs, at 15°C. The latency calculated to the time of onset of the muscle action potential was 14·9 ± 0·1 msecs. The eye movements followed a repeated tap stimulus of 10/sec. and showed a ripple of movement on a sustained deviation at 30/sec. The adequate stimulus for the reflex was brushing or tapping: sustained pressure, vibration and heat were not effective. Repetition of the stimulus evoked a facilitated response; evidence is presented that points to a peripheral facilitation at the neuromuscular junction and a central facilitation at interneurons in the central reflex pathway.Eye protective reflexes in two other sharks are described. InGaleorhinus australisMacleay, the eye was covered by a well‐developed nictitating membrane. InCephaloscyllium isobellaBroussonet, the eye was closed mainly by an upward movement of the lower lid. The reflexogenic and facilitatory zones of these two species are described. The reflex in S.acanthiasis compared with the sensory blink reflex in higher vertebrates, and it is suggested that the abduction of the eye in this fish serves to protect the cornea from mechanical damage.

ISSN:0004-945X    

DOI:10.1038/icb.1963.22

出版商:Nature Publishing Group    

年代:1963

数据来源: WILEY

摘要:

SUMMARYA method is described for the estimation of free testosterone in human peripheral plasma. This method which uses the double isotope dilution derivative principle with C14‐testosterone as marker steroid, H3‐acetic anhydride as deriving agent, shows normal male levels to range from 0.49–0.98 μg./100 ml. and females from less than 0.05 μg./1OO ml. to 0.31 μg./100 ml. The results obtained by this method have been compared with those given by other techniques for the estimation of this steroid hormone.

ISSN:0004-945X    

DOI:10.1038/icb.1963.23

出版商:Nature Publishing Group    

年代:1963

数据来源: WILEY

摘要:

SUMMARYThe concentrations of total liver storage (non‐haem) iron, of the forms of this iron, and of plasma iron and total iron‐binding capacity, were determined in healthy adult sheep and cattle of both sexes.Individual variability in total non‐haem liver iron and in the water‐soluble (presumably ferritin) and water‐insoluble (haemosiderin) fractions of this iron was found to be high in both sexes of both species. Differences between the sexes were not significant but total storage iron and ferritin iron levels were significantly higher in sheep than in cattle. From two‐thirds to three‐quarters of the total storage iron occurred in water‐soluble form. This was assumed to be ferritin, although attempts to isolate this compound were unsuccessful.Plasma iron and total iron‐binding capacity concentrations and percentage saturation values were found to be of the same order as those found previously for sheep and cattle and for other species. Evidence was obtained that plasma iron concentrations and percentage saturation values are significantly higher in ewes than in rams.

ISSN:0004-945X    

DOI:10.1038/icb.1963.24

出版商:Nature Publishing Group    

年代:1963

数据来源: WILEY

摘要:

SUMMARYA technique is described for detecting damage to cells in culture using P32. The method is relatively simple and results obtained with it are reproducible.The method depends on the principle that P32passes from cells into a non‐toxic medium at a rate which is a property of the particular type of cell. Cytotoxic agents cause an increased rate of leakage of P32from cells.The method was satisfactory with all of the cultures which were studied: the L‐fibroblast, primary cultures of the 16–6 rat thyroid carcinoma and rat kidney, and subcultures of these rat cells.Four types of cytotoxic agents were shown to cause an increased loss of P32from the cells on which they were tested: the natural rat cytotoxin in rabbit serum, NaOH, antisera to rat tissues, and mechlorethamine hydrochloride (“Mustargen”).Data are presented to show that increased P32loss is due to cell damage.

ISSN:0004-945X    

DOI:10.1038/icb.1963.25

出版商:Nature Publishing Group    

年代:1963

数据来源: WILEY

摘要:

SUMMARYTechniques are described for preparing monolayers of normal rat alveolar and peritoneal macrophages. A comparison has been made of the relative bactericidal power of these phagocytes against two species of organisms. It has been shown that alveolar macrophages are less able to killE. coliandS. aureus in vitrothan are peritoneal macrophages. Other differences have been measured between these two types of cell; acid phosphatase and lysozyme levels were both found to be considerably higher in the lung macrophages. The part played by normal alveolar phagocytes in immunity is discussed, and it is suggested that present criteria for characterising components of the RES may be inadequate since “RE” cells may differ functionally and physiologically from one organ to another within the same animal.

ISSN:0004-945X    

DOI:10.1038/icb.1963.26

出版商:Nature Publishing Group    

年代:1963

数据来源: WILEY

摘要:

SUMMARYIn a controlled experiment using 86 pairs of male white mice matched for weight, the blood alcohol level after intraperitoneal injection of ethyl alcohol was slightly but significantly elevated in animals in which a closed fracture of the femur was produced at the time of the alcohol injection. Significant elevation of blood alcohol was present at half an hour after alcohol injection and was still present three hours after injection. Blood alcohol levels in both injured and control animals decreased linearly at the same rate with the logarithm of time, but the regression line of the blood alcohol levels of the injured animals was higher than that of the control animals.

ISSN:0004-945X    

DOI:10.1038/icb.1963.27

出版商:Nature Publishing Group    

年代:1963

数据来源: WILEY