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101.
A simple and rapid procedure to make yeast cells permeable by agitating with toluene-ethanol, (TE) 1:4, v/v was developed. The permeated cells retained their ability to catalyze certain enzyme reactions. Temperature and duration of agitation during TE treatment played an important role in retention of the catalytic potential of permeated cells. The in situ assay using permeated cell preparations was more sensitive even in the absence of added cofactors than in the vitro assay in detecting assimilatory nitrate reductase (NAD(P)H:nitrate oxidoreductase, EC 1.6.6.2) (NAR) activity in Candida utilis. Using in situ assay technique, different mechanisms regulating the biosynthesis of NAR in C. utilis were investigated. Nitrogen starvation did not lead to derepression of NAR. NO3-ions were absolutely essential for induction and maintenance of high levels of NAR activity. Cells grown on ammonium nitrate possessed relatively lower levels of NAR. Kinetics of NAR induction were followed as a function of time and inducer concentration. The influence of various cations on the induction of NAR by nitrate was investigated. A wide range of D-amino acids induced NAR synthesis. Of 22 L-amino acids tested only phenylalanine induced significant levels of NAR. Various intermediates of the pathway of nitrate reduction influenced the rate of NAR induction. There was a rapid disappearance of in vivo activity of the enzyme of induced yeast cells on nitrogen starvation, and the rate of loss was accelerated by the presence of NH4+.  相似文献   
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Pigs were given 6 daily injections of isoprenaline or pilocarpine. At necropsy the parotid, submaxillary and sublingual salivary glands were removed and weighed. Histological sections were prepared from several regions of each gland and the cross-sectional area of their acini was measured in treated and control animals by means of a Quantimet Image Analysis System. Both isoprenaline and pilocarpine produced a significant increase in the weight of the parotid and submaxillary glands, which was accompanied by an increase in acinar area. There was no change in the weight of the sublingual gland with either drug, but isoprenaline did induce an increase in the area of sublingual acini. A comparison is made of the changes in weight and structure of the salivary glands as shown by these methods.  相似文献   
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Tuberculosis incidence and mortality rates are rising steeply, reflecting economic hardship and the deterioration of the health infrastructure. The human and technical resources needed to reverse this trend are on hand, but cannot be used effectively without an adequate financial input. The cost of controlling tuberculosis now is modest compared with the cost of allowing it to increase.  相似文献   
106.
The aim of this study was to identify the factors influencing entry of women with invasive breast cancer into clinical trials in Scotland. Women diagnosed during 1987 and 1993 were identified from cancer registry data records and their case notes reviewed. Entry into clinical trials was recorded, along with clinical and demographic data for 4688 patients. In 1987, the proportion of women entering clinical trials was 12.3% and, allowing for shorter follow-up, this appeared unchanged in 1993. Patients seen by surgeons with a high case load and those referred to an oncologist were approximately seven times and three times, respectively, more likely to enter a clinical trial (P < 0.0001). The area of Scotland (Health Board) where the woman was first treated also influenced study entry (P < 0.0001), whereas social deprivation had no effect (P = 0.93). Older women, especially those over 80 years of age, were less likely to enter studies (P = 0.05). Extending the management of patients by specialist multidisciplinary teams should increase recruitment into clinical trials and help to identify better treatments for women with breast cancer.  相似文献   
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