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Biomedical subjects

J Lewis

Publications and source records attributed to J Lewis.

At least 343 records · Page 19Linked to original sources
PubMed1987

Oral protein and energy supplements in cancer patients.

Reduced food intake is a common problem in patients with malignant disease. Oral supplementation is the simplest and least invasive method of increasing the nutrient intake, and a number of neutral protein and energy supplements are available. This study was carried out to assess the value of these supplements when incorporated into the everyday diet of cancer patients. The first stage of the study evaluated the palatability of the energy and protein supplements available. Polycal was found to be the most acceptable energy supplement and Protifar the most acceptable protein supplement. These two products were then used to assess their contribution to the protein and energy intake of cancer patients when incorporated into everyday food. The rise in protein and energy intake was statistically significant but the increase in energy was not thought to be clinically important.

Dietary Carbohydrates↗
PubMed1986

Normal development of the skeleton in chick limb buds devoid of dorsal ectoderm.

It has been suggested that the ectoderm on the dorsal and ventral faces of the limb bud plays a part in controlling the pattern of cartilage differentiation. To test this, the dorsal wing bud ectoderm in the chick embryo was destroyed by irradiation with ultraviolet light at stage 17-19, at the very beginning of limb bud development, but the apical ectodermal ridge was spared. The irradiated ectoderm disappeared within 24 hr (by stage 23-24) and did not regenerate thereafter; thus the dorsal surface of the limb bud was kept denuded throughout most of the period of skeletal pattern formation. By 6 or 7 days after the irradiation (stage 35), when the rudiments of all the adult skeletal elements are normally present in recognizable form, the irradiated wings could be placed into two categories, those that were approximately normal in shape and those that had curled dorsally. All of these limbs were reduced in size, to varying degrees, when compared to their controls and lacked dorsal soft tissues. The limbs that were normal in shape, however, even though sometimes denuded over practically the whole extent of their dorsal surface, almost always had a complete and normally proportioned cartilage pattern, suggesting that ectoderm (other than the apical ectodermal ridge) does not exert any direct control over the development of the limb cartilage pattern. However, many of those limbs that had curled as a result of the irradiation did have major pattern deformities, suggesting that the topology of cartilage differentiation does depend on the shape of the limb bud.

Animals↗
PubMed1986

Sensory nerve routes in chick wing buds deprived of motor innervation.

To what extent do motor and sensory nerve fibres depend on one another for guidance during the development of peripheral nerve patterns? This question has been examined by looking at the paths taken by sensory nerve fibres growing into the embryonic chick wing in the absence of motor axons. The precursors of the motoneurones were destroyed by irradiating the appropriate part of the neural tube with a focused beam of ultraviolet light, before axons had grown out. The limb nerve patterns seen 5 to 7 days later revealed that sensory fibres followed the usual paths of main nerve trunks and formed cutaneous nerve branches in an almost normal way. However, the sensory fibres did not take the paths where muscle nerve branches are normally seen. Apparently, sensory axons for the most part do not depend on motor axons for guidance, except in the case of proprioceptive fibres, which require guidance from motor axons over the final steps of their path into muscle.

Animals↗
PubMed1985

Cigarette smoking and the risk of endometrial cancer.

Because of evidence of reduced estrogen excretion in the urine of women who smoke cigarettes and evidence linking estrogen levels to the risk of cancer of the female reproductive system, we evaluated the risk of endometrial cancer in relation to cigarette use in a hospital-based case-control study of 510 women with endometrial cancer (cases) and 727 women with other cancers (controls). The rate-ratio estimate (relative risk) for current smokers as compared with women who had never smoked was 0.7 (95 per cent confidence interval, 0.5 to 1.0), and for former smokers the estimate was 0.9 (0.6 to 1.2). For women currently smoking 25 or more cigarettes per day, the rate-ratio estimate was 0.5 (0.3 to 0.8). The effect of current smoking of at least 25 cigarettes per day appeared to be confined to postmenopausal women, among whom the estimate was 0.5 (0.2 to 0.9). Among premenopausal women the estimate was 0.9 (0.4 to 2.2), but the difference between these two estimates could have been due to chance. The data suggest that women who smoke heavily may have a lower risk of endometrial cancer than nonsmokers. The present findings do not have direct public health importance since cigarettes, overall, have serious deleterious effects. However, if these results are confirmed, elucidation of the underlying mechanisms whereby smoking reduces the risk would be of interest and might be useful in the development of strategies for preventing endometrial cancer.

Adult↗
PubMed1985

Assessment of thromboresistance of intravenous cannulae by 125I-fibrinogen scanning.

Assessment of potentially thromboresistant polymers and other materials has been impeded by the lack of a simple and safe test procedure in man. This report describes the use of a portable gamma radiation detector to assess accumulation of 125I-fibrinogen in thrombi related to intravenous cannulae. The method was first employed in 19 dogs and one sheep with FEP-Teflon forelimb intravenous cannulae which were scanned for up to 6 h after insertion. Results were compared with findings at post mortem examination. Eleven thrombi developed, nine of which emitted more than 3500 counts per minute; eight of these (89%) were detected by external scanning. The smallest thrombus detected weighed 0.7 mg. The method did not distinguish between thrombus and hematoma. Fifty FEP-Teflon cannulae were then studied in 39 patients after injection of 100 microCi 125I-fibrinogen. Cannulae and control sites were scanned twice daily and an independent blind clinical appraisal was performed by an experienced nurse. A rise in percentage uptake (count at a limb site/heart count X 100) of 20 or a difference of 40 between adjacent sites was regarded as a positive test. Scans became positive up to 30 h before clinical evidence of phlebitis was observed. The interval between insertion and thrombosis of both large and small cannulae detected by scanning was significantly shorter than that determined by clinical assessment (p less than 0.001). Physical signs of phlebitis were noted with 58% of large cannulae (16 or 18 gauge)and 33% of small cannulae (22 gauge) at the time of removal. Positive 125I-fibrinogen tests were obtained with 70% of large cannulae and 75% of small cannulae. 125I-fibrinogen scanning is a safe simple sensitive technique to detect thrombosis related to intravenous cannulae. The test should enable comparisons of different cannula materials in man.

Animals↗
PubMed1985

Possible adverse reactions to an enzyme-containing washing powder.

Following the launch of an enzyme (alcalase) containing washing powder, the manufacturers received numerous complaints from domestic users suggesting that it was responsible either for the precipitation of a rash or the exacerbation of a pre-existing rash. The 255 individuals living in London postal districts who complained to the manufacturers were contacted: 80 of them agreed to be investigated by patch and prick testing, and to a user test involving the double blind wearing of vests washed with the product. The results failed to substantiate that the enzyme containing washing powder was responsible for any dermatological problem.

Adolescent↗
PubMed1984

Lysine tRNA and cell division: a G1 cell cycle mutant is temperature sensitive for the modification of tRNA5Lys to tRNA4Lys.

Ts-694 is a temperature sensitive mutant of hamster cells which is blocked in the G1 phase of the cell cycle at the restrictive temperature of 39 degrees. A comparison of the Lys-tRNA isoacceptors by RPC-5 chromatography showed a decrease in tRNA5Lys and an increase in tRNA4Lys at 39 degrees. This was identical to the changes seen in confluent cultures at the permissive temperature of 33 degrees. These Lys-tRNA changes were not seen in ts-694 cells blocked in G1 by isoleucine deficiency, nor in two other G1 ts mutants at the restrictive temperature. Cells trapped in S phase by a thymidine block also contained decreased levels of tRNA4Lys when raised to 39 degrees. Both tRNA4Lys levels and cell division increased when the cells were returned to the permissive temperature. An in vitro assay was established for the modification of tRNA5Lys to tRNA4Lys with tRNA6Lys and tRNA2Lys as intermediates. The first reaction is the synthesis of tRNA6Lys which involves the introduction of a modified uridine at the third position of the anticodon. Extracts of 694 cells grown at 33 degrees were able to modify rat liver [3H] tRNA5Lys to tRNA6Lys and tRNA4Lys in vitro when assayed at 25 degrees but not at 39 degrees. Extracts of Balb/c 3T3 cells, however, were more active at 39 degrees than at 25 degrees showing that the normal enzyme is not temperature sensitive. Ts-694 cell tRNA, isolated from cells grown at 33 degrees was aminoacylated at both 25 degrees and 39 degrees with rat liver synthetases. tRNA4Lys was present at both temperatures indicating that ts-694 cells do not contain a temperature sensitive tRNA4Lys.

Animals↗