Formation of a rate-limiting intermediate in 5S RNA gene transcription

We have performed in vitro kinetic analyses of transcription from the 5S gene promoter in order to resolve the rate-limiting events which lead to accurate transcription of the 5S RNA gene. We demonstrate that a rate-limiting intermediate can be formed during an extended incubation prior to initiation of transcription. Formation of such a complex is temperature-dependent, requires magnesium and ATP, consists of stoichiometric amounts of the known class III transcription factors and RNA polymerase III on 5S DNA, and eliminates the normal lag in attainment of a steady-state rate of transcription. This complex is therefore different from the "stable complex" minimally required for template commitment. Further analyses demonstrate that TFIIIB, like TFIIIA and TFIIIC, can be stably sequestered on the 5S gene and also allow us to formulate the following order of factor interactions on the 5S gene: TFIIIA, TFIIIC, TFIIIB, RNA polymerase III.

Migrant labor in agriculture: an international comparison

The May 1984 Conference on Migrant Labor in Agriculture at the University of California-Davis discussed papers by 22 farm labor experts from 12 nations. Each industrial nation utilizes a different set of public and private policies to supply workers for labor-intensive agriculture, but none is entirely satisfactory. Labor-intensive agriculture is becoming more dependent on workers who are shut out of labor markets. Some countries have simply accepted foreign workers in agriculture, while others have adopted policies to integrate farm and nonfarm labor markets. Polices to reduce agriculture's reliance on workers-without-options include restructuring employment practices to employ fewer seasonal workers for longer periods, mechanizing production, and importing fruits and vegetables from nearby developing countries. This article explains the salient features of labor-intensive agriculture, the various polices for obtaining seasonal farmworkers, and options to reduce farming's dependence on migrant labor.

Synthesis of cytochrome P-450 in isolated liver cells during exposure to hyperoxia

Mouse hepatocytes were separated within 15 min of the death of the animal. A method of determining cytochrome P-450 was developed and used to show that cells prepared quickly still contained normal levels of this pigment. Cells suspended in complete culture medium were exposed to various partial pressures of oxygen for 30 min. When exposed to anoxia there was a 30% loss of cytochrome; at 30-50 Torr, a 30% increase; to 150 Torr, a 10% decrease; and to 700 Torr or higher, 30%-60% increase. The time course of the increase, at those tensions at which it was obtained, showed the increase occurred for 1 to 2 h and was followed by a continual loss. This final loss was at approximately the same rate at all tensions, whether or not there was an initial rise. Thus the cytochrome P-450 levels of isolated hepatocytes show qualitatively the same response to varying oxygen tensions that they do in intact animals.

Estradiol, estrone, and gonadotropin levels after use of vaginal estradiol

The vaginal absorption of 0.5-mg tablets of micronized estradiol was evaluated in postmenopausal women. In a single-dose study, one hour after insertion, a 5.3-fold rise in mean serum estradiol levels and 1.5-fold rise in mean serum estrone levels were observed. Mean levels of luteinizing hormone and follicle-stimulating hormone were significantly depressed. In a three-week alternate-day regimen, mean serum levels of estradiol were consistently two to three times greater than those of estrone 12 hours after insertion. Vaginal absorption of micronized estradiol tablets into the systemic circulation was found to be rapid and efficient. The vaginal route was acceptable and well tolerated by patients. In addition, the major conversion of estradiol to estrone that follows oral or sublingual administration was reduced. The vagina may be a preferred alternate route for estrogen replacement therapy in selected patients.

Transcription of class III genes: formation of preinitiation complexes

Class III genes require multiple cellular factors for transcription by RNA polymerase III; these genes form stable transcription complexes, which in the case of Xenopus 5S genes are correlated with differential expression in vivo. The minimal number and identity of the factors required to form both stable and metastable complexes on three class III genes (encoding, respectively, 5S RNA, transfer RNA, and adenovirus VA RNA species) were determined. Stable complex formation requires one common factor, whose recognition site was analyzed, and either no additional factors (the VA gene), a second common factor (the transfer RNA gene), or a third gene-specific factor (the 5S gene). The mechanism of stable complex formation and its relevance to transcriptional regulation were examined in light of the various factors and the promoter sequences recognized by these factors.

The contribution of bidimensional echocardiography in the diagnosis of cardiac tumours. Based on 25 observed cases

This paper reviews 25 intracardiac tumours (12 myxomas and 13 thrombi) studied by T.M. echography, bidimensional (2-D) echography and cineangiography during a two year period. In addition, five cardiac tumours (two myxomas, three thrombi) were studied by echography alone, and correctly diagnosed. T.M. echography gives false negative results, whereas both 2-D echo and cineangiography give reliable diagnosis. However, 2-D echo should be the procedure of choice as it is non-invasive, and may be used on patients with equivocal symptoms. Since bidimensional echography has become available during the past two years, 12 myxomas have been correctly diagnosed, compared to 14 found during the previous 13 years.

Sublingual absorption of micronized 17beta-estradiol

The sublingual absorption rates, the sustained effects, te biologic activity, and the metabolism of micronized 17beta-estradiol (E2) were measured in 10 postmenopausal women. E2 (0.5 mg) was administered in a single sublingual dose to five of the patients. An alternate-day schedule with the same dosage was used for the other five patients. In the single-dose study, a twenty-six fold increase in serum E2 and a ninefold increase in serum estrone (E1) concentrations were observed 1 hour after the sublingual deposition of E2 (0.5 mg). Serum concentrations of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were significantly decreased within 6 hours. The rise in E2 was early and peaked in the first 2 hours. The rise in E1 was slower and progressive, reaching its maximum thirteenfold increase at 4 hours, and remained two and one half times the baseline of 29 pg/ml at 24 hours, whereas E2 returned to the baseline level of 24 pg/ml. When micronized E2 was given in a dosage of 0.5 mg sublingually every other night, increased circulating levels of estrogens continued to be elevated at a minimum two and one-half fold baseline level for the week of study.

[Assisted circulation during coronarography: advantages and limitations. A report on 63 cases (author's transl)]

During 2588 coronarography examinations conducted over a period of 4 years, assisted circulation was employed in 63 cases to reduce the risks of the examination procedure in particularly debilitated patients. These high risk cases included 48 patients with unstable angina resistant to medical treatment and 45 cases of recent infarcts with complications. Mortality with assisted circulation was very low, in spite of the severe nature of the affections, but the authors use this technique in only a limited number of cases, mainly because of the risk of lower limb ischemia, and the possibility of using intravenous nitroglycerin and analgesia from neuroleptics for examination. For this reason the number of cases examined in this way has dropped from 4% in 1977 to 2% in 1978, though assisted circulation is still employed in certain particularly severe cases of angina, and for infarcts with complications.

Systemic absorption and sustained effects of vaginal estrogen creams

Systemic absorption and sustained effects of two estrogen vaginal cream preparations (Premarin and Estrace) were measured in 29 postmenopausal women receiving daily applications. With both preparations, vaginal absorption of estrogens into the systemic circulation was rapid, efficient, and sustained. It is apparent that estrogen vaginal cream preparations, as widely used in clinical practice for their local effects on the vaginal mucosa, actually result in sustained high estrogen levels in the systemic circulation. The vaginal route shows promise when systemic estrogen therapy is indicated, but is dangerous when estrogen is contraindicated.

Immutable and Variable Transition State Structures. A Reply

The factual basis of, and the theoretical reasoning behind, a recent suggestion by Poh that transition state structures may or may not vary according to the severity of substituent change are critically examined in terms of currently held views. Both aspects of Poh's paper are found to be defective. Some results on the rates of solvolysis of diarylmethyl p-nitrobenzoates in ethanol/water solvent mixtures are considered. A superficial examination of the Hammett p and Winstein-Grunwald m parameters indicates that Poh's suggestion of immutable transition states is exemplified by this work, but a more detailed treatment shows that p and m are not necessarily functions of transition state charge separations alone.

Vascular access in a University transplant and dialysis program. Results, costs, and manpower implications

Vascular access has become the most common operation performed at North Carolina Memorial Hospital, Chapel Hill. Three hundred vascular access procedures performed between 1971 and 1975 were reviewed as to results, costs, and manpower commitment. Subcutaneous radial arterial venous fistula was the procedure of choice, with a 67% two-year patency and the lowest incidence of complications. An average of 1.7 operations per patient was necessary to maintain access. Patients used an average of 19 hospital days per year of dialysis for vascular access and an average of 35 hospital days per year of dialysis for all medical problems. Cost of hospitalization averaged $6,818 per patient per year of dialysis, and for vascular access alone averaged $3,452 per patient per year of dialysis. To create and maintain vascular access, 1,000 hours of operating room time were required, at an expense of $200,000. Vascular access in support of patients undergoing chronic hemodialysis requires a massive commitment of dollars, time, and personnel.

Micronized 17 beta-estradiol for oral estrogen therapy in menopausal women

Micronized 17beta-estradiol (E2) was used as oral replacement therapy in 369 patients with estrogen deficiency and related menopausal symptoms. Over 95 percent of 319 patients evaluable for efficacy gained satisfactory relief of their symptoms from cyclic (on 21 days/off 7 days) E2 therapy. Approximately 77 percent required no adjustment of their initial daily dose, viz, 1 mg (5 or less hot flushes per day) or 2 mg (6 or more flushes daily). In addition, 80 percent (58/72) of the patents who did not obtain adequate control from their starting dose were successfully titrated, either upward to a maximum of 4 mg/day or downward for maintenance. Overall, a higher percentage of patients were treated successfully with 2 mg daily (209/319; 66 percent) than with 1 mg/day (22 percent). About 8 percent of the patients required 3 or 4 mg daily, while 4 percent failed to derive adequate benefit from micronized E2. Oral E2 therapy was well tolerated; hence, the attrition rate due to side effects or lack of control was only 6 percent (22/369). Moreover, all laboratory fingings were within normal limits, even in patients treated with E2 for over 12 months. Coincidental endometrial changes were found in 9 patients, all of whom had received long-term (9 months-3 years) estrogen therapy prior to entering this study. Thus, the stste of the endometrium should be determined before any estrogens are given for the monopause. It is concluded that micronized E2 is highly efficacious, well accepted, and safe for oral estrogen-replacement therapy in menopausal women.

Circulating estradiol, estrone and gonadotropin levels following the administration of orally active 17beta-estradiol in postmenopausal women

Ingestion of a single tablet containing 2 mg micronized 17beta-estradiol (E-2) produced marked increases in the serum concentrations of E-2 and estrone (E-1) in 9 postmenopausal women. The rise in circulating E-2 became significant within 2 h, reached a maximum (110 pg/ML; 437% increase) at 5 h, and remained significantly elevated at 8 h posttreatment. By 24 h, the serum E-2 concentration was not significantly different than baseline. In contrast, a more rapid (within 1 h) and pronounced (4-fold) increase in the serum concentration of E-1 was observed. This rise continued until a peak (467 pg/ml; 2000%) was reached 6 h posttreatment. Thereafter, the serum E-1 concentration declined progressively but was still significantly elevated (140 pg/ml; P smaller than 0.01) 24 h after treatment. Serum concentrations of FSH AND LH were significantly decreased within 6 and 3 h, respectively and both gonadotropins remained significantly suppressed 24 h following the ingestion of E-2. The ratios of circulating E-1: E-2 reported herein (ca. 3-6) were much higher than those observed by other investigators following iv E-2 (I.E., smaller than 1). Thus the data indicate that micronized E-2 peros is readily absorbed and that during this process a significant portion of the hormone is converted to E-1 by the gstrointestinal tract. In addition, 2 mg oral E-2 exerts significant biologic activity as assessed by serum gonadotropin suppression.

Cervical cancer. Use of a non-physician health team for screening procedures

A team of non-physician personnel has been trained in cytologic screening for cervical cancer. In a county hospital clinic setting among low income women whose annual pelvic examinations were being by-passed by physicians, this three-person team has performed pelvic examinations and screening under physician supervision for one year. Results of the first year's experience, measured in cancer detection and in recognition and referral of benign gynecological disease as well, would suggest that a non-physician team, with a registered nurse doing a pelvic examination of screening type, can screen for cervical cancer and other pelvic disease efficiently and without a significant lowering of the quality of medical care. The training and use of teams of allied health care personnel directed by physicians is suggested as a practical means of overcoming the increasing shortage of physician services in annual screening for cervical cancer among low income women.

Behavioral therapy for "apathy" of hospitalized schizophrenics

20 chronic schizophrenic adult female patients in a ward of a hospital for the mentally ill were placed on schedules of reinforcement designed to establish or strengthen behaviors incompatible with the diagnostic statement “apathetic.” Another 20 patients on the same ward received standard ward therapy. 30 behavioral samples, spaced evenly in ½-hr. intervals, were obtained for each of the patients for 3 5-day periods: before, during, and on termination of the program. Apathy was defined as the degree to which a patient at the time of any of the 30 daily observations engaged in one—and only one—clearly discernible behavior. While the degree of apathy was equal for experimentals and controls at the beginning of the experiment, those patients who were subjected to the schedules of reinforcement were significantly less apathetic at the termination of the experiment than the controls who were given normal ward therapy but who were not subjected to such schedules. The implications of these findings are discussed.