Non-functional variants of yeast mitochondrial ATP synthase subunit 8 that assemble into the complex

Myocardial and pulmonary beta-adrenoceptors can be imaged with 2-(S)-(-)-(9H-carbazol-4-yl-oxy)-3-[1-(fluoromethyl)ethyl]amino-2- propanol (S-1'-[18F]fluorocarazolol, I). Quantification of unmodified fluorocarazolol in plasma is necessary for analysis of PET images in terms of receptor densities. We have determined I and its radioactive metabolites in rat, sheep and human plasma, using (1) solid-phase extraction (C18) followed by reversed-phase HPLC and (2) direct injection of untreated plasma samples on an internal-surface reversed-phase (ISRP) column. The two methods were in good agreement. Unmodified I decreased from over 99% initially to less than 5%, 5-10% and 20% at 60 min post-injection in rats, sheep and human volunteers, respectively. Protein binding in sheep and human plasma was determined by ultrafiltration. The fraction of total plasma radioactivity bound to protein and the fraction representing unmodified radioligand were linearly correlated, suggesting that fluorocarazolol was more than 70% protein-bound, whereas its metabolites showed negligible protein binding. Direct injection of plasma on an ISRP column seems a convenient method for quantification of lipophilic radioligands such as fluorocarazolol.     

Effects of prenatal androgenization and postnatal steroid treatment on growth hormone, insulin-like growth factor I and II, insulin, thyroxine, and triidothyronine concentrations in beef heifers

A 2 x 3 factorial arrangement of treatments was used to elucidate the mechanism(s) by which prenatal androgenization improves postnatal rate and efficiency of growth and composition of gain in beef heifers. Fifteen control (C) and 15 prenatally androgenized (PA) Angus x Simmental heifers (prenatal treatment, Pretrt) received no (N), estrogen (E), or estrogen and testosterone (ET) implants postnatally (postnatal treatment, Posttrt) to evaluate whether the postpubertal growth response after prenatal androgenization could be induced in prepubertal heifers. Blood was collected from the heifers at 6 +/- 1, 9 +/- 1, and 12 +/- 1 mo of age and analyzed from serum concentrations of growth hormone (GH), IGF-I, IGF-II, insulin, thyroxine (T4), and triiodothyronine (T3). Season of the year had a greater effect on hormone concentrations than either Pretrt or Posttrt, and there were no Pretrt x Posttrt interactions. Prenatal treatment, PA, had no effect on GH; however, Posttrt E and ET increased (P < .001) GH concentrations. Prenatal treatment, PA, increased (P < .05) IGF-I concentrations, and there was a nonsignificant increase (P = .11) in IGF-I concentrations with Posttrt E and ET. Concentrations of IGF-II were unaffected by Pretrt PA; however, they were lower (P < .01) in the Posttrt E and ET groups. Insulin, T4, T3, BW, and ADG were not affected by Pretrt and Posttrt. Concentrations of GH and IGF-I were increased in heifers that received Pretrt PA and(or) Posttrt E and ET in a manner to support improved growth performance; however, BW and ADG were similar. In prepubertal beef heifers, factors in addition to increased GH and IGF-I seem to be necessary for improved growth performance.     

The Medical Expenditure Panel Survey: a national health information resource

This article describes the Medical Expenditure Panel Survey (MEPS), the third in a series of nationally representative surveys of medical care use and expenditures sponsored by the Agency for Health Care Policy and Research. The MEPS is designed to provide extensive data on the types of health care services American use, how frequently they use them, how much is paid for the services, and who pays for them. It also will provide information on the types and costs of private health insurance available to the U.S. population. The survey is unparalleled in its degree of detail, as well as its ability to link medical care use, payments, and health insurance coverage to specific survey respondents and their families. It allows analysts to examine how individual and family characteristics, including the characteristics of their health insurance, affect medical care use and spending. This article discusses each of the MEPS components, focusing on design enhancements that have been made since the survey was last conducted nearly a decade ago.     

Reductions in self-injury produced by transcutaneous electrical nerve stimulation

Transcutaneous electrical nerve stimulation is used to reduce pain but also may be useful for self-injurious behavior (SIB). In the current investigation, a microcurrent electromedical device, classified as a transcutaneous electrical nerve stimulator (TENS), was applied with a man with Down syndrome who displayed SIB that persisted in the absence of social contingencies. Although clinically significant results were not maintained, a clear difference in the rates of SIB during active and inactive TENS was observed.     

Fine needle aspiration cytology of papillary neoplasms

This article covers the fine needle aspiration biopsy cytomorphology of papillary carcinomas of different organs, differential diagnoses, and clinical correlation. Diagnostic problems and helpful cytologic features are emphasized. The purpose is to have a concise source of information that helps the pathologist to evaluate these neoplasms.     

D-erythro-neopterin biosynthesis in the methanogenic archaea Methanococcus thermophila and Methanobacterium thermoautotrophicum deltaH

The steps in the biosynthetic transformation of GTP to 7,8-dihydro-D-erythro-neopterin (H2neopterin), the precursor to the modified folates found in the methanogenic archaea, has been elucidated for the first time in two members of the domain Archaea. In Methanococcus thermophila and Methanobacterium thermoautotrophicum deltaH, it has been demonstrated that H2neopterin 2':3'-cyclic phosphate is an intermediate in this conversion. In addition, the formation of the pterin ring of the H2neopterin 2':3'-cyclic phosphate is catalyzed not by a single enzyme, as is known to occur with GTP cyclohydrolase I in the Eucarya and Bacteria, but rather by two or more enzymes. A 2,4,5-triamino-4(3H)-pyrimidinone-containing molecule, most likely 2,5-diamino-6-ribosylamino-4(3H)-pyrimidinone 5'-triphosphate, has been identified as an intermediate in the formation of the H2neopterin 2':3'-cyclic phosphate. Synthetic H2neopterin 2':3'-cyclic phosphate was found to be readily hydrolyzed by cell extracts of M. thermophila via the H2neopterin 3'-phosphate to H2neopterin, a known precursor to the pterin portion of methanopterin.     

A prospective study of the effect of fundoplication on primary and secondary peristalsis in the esophagus

BACKGROUND: Delay of prenatal care is an important risk for poor birth outcome, yet its association with maternal knowledge and beliefs remains insufficiently studied. This research examined the relationship of unintended childbearing and beliefs about the importance of prenatal care with initiation after the first trimester, adjusting for key sociodemographic determinants. METHODS: One hundred fifty-four Texas hospitals accounting for 80 percent of state births were asked to collect surveys from all women delivering infants during a one-week interval in 1986. Seventy-four percent of hospitals and 70 percent of women participated (n = 2032). No differences occurred between the sample and the population on rates of delayed care and low birthweight or maternal demographics. RESULTS: Since delayed prenatal care is more frequent among low-income women, analyses were limited to those below the 200 percent poverty level. After adjustment for maternal age, marital status, education, parity, race, and health insurance status employing logistic regression, unintended births were 1.6 times more likely to involve delayed care. Mothers who believed prenatal care was unimportant were 2.1 times more likely to delay care. These coefficients exceeded or about equaled those for the covariates. CONCLUSIONS: Preconception education about the value of prenatal care and family planning programs to prevent unintended pregnancies should be conducted together with efforts to overcome financial and structural barriers if progress toward national prenatal care objectives is to be achieved.     

The integration of the corneal and limbal fibrils in the human eye

The precise orientation of the collagen fibrils in human cornea and sclera and the method by which these two areas fuse together at the limbus have never been determined, despite the importance of this information. From a consideration of the mechanics of the system, fibril orientation in the tissue has the potential to affect the curvature of the cornea so, by inference, refractive problems such as astigmatism involving an incorrect curvature of the cornea may be related to fibril orientation. The high intensity and small beam size of a synchrotron x-ray source has enabled us to study fibril orientation in post-mortem human cornea and sclera. Previously we have revealed two preferred directions of orientation in the cornea (Meek, K. M., T. Blamires, G. F. Elliot, T. Y. Gyi, and C. J. Nave. 1987. Curr. Eye Res. 6:841-846) and a circumcorneal annulus in the limbus (Newton, R. H., and K. M. Meek. 1998. Invest. Ophthalmol. & Visual Sci. 39: 1125-1134). Here we present the results of our investigation into the relationship between these two features. Our measurements indicate that the corneal fibrils oriented in the two preferred directions bend at the limbus to run circumferentially. On the basis of these results we propose a model as to how the human cornea and sclera fuse together.     

Motor function of the proximal stomach and visceral perception in gastro-oesophageal reflux disease

Oxytocin (OT) is present in the mammalian testis and has been shown to play a role in the modulation of seminiferous tubule contractility and steroidogenesis. However, stage-specific effects of the peptide have not been previously investigated. In this study, computer-assisted analysis and time-lapse videomicrography were used to investigate basal contractility and the response to OT of seminiferous tubules at specific stages of the spermatogenic cycle. Adult rat testes were placed in fresh oxygenated DMEM F12 medium, decapsulated, and the tubules gently teased apart. Stages were identified by transillumination and a 10 mm section of tubule at each of stages IV-V, VII-VIII and XIII-I was placed in a microslide chamber and perifused with medium. After a control period of 3 h, OT (2 nM) was given for 1 h, followed by another control period of 1 h. The experiment was repeated using tubules from different rats and data were analysed to give arbitrary units of tubule contractility. Contractility was observed in all the tubules studied and the contractile activity was shown to vary depending on the stage of the spermatogenic cycle. Mean basal contractility at stages VII-VIII, the time when sperm are shed from the epithelium, was significantly lower than that at stages IV-V and XIII-I. The response of the tubules to OT was also stage-dependent, with the peptide producing the largest increases in contractile activity at stages VII-VIII and having no effect at stages IV-V. We postulate that these stage-specific differences in basal and OT-stimulated contractility may be important in co-ordinating the movement of developing germ cells towards the lumen of the seminiferous epithelium and in the process of spermiation.     

Predicting the development of late-life late-onset drinking problems: a 7-year prospective study

There has been little empirical study of risk factors for the development of late-life late-onset drinking problems. In the current prospective study, we compare two groups of older adults who, at a baseline assessment, were nonproblem drinkers: individuals who developed drinking problems over the course of the next 7 years (n = 77) and those who did not (n = 197). Late-onset problem drinkers reported mild to moderate drinking problems and spontaneous remission rates were high. Compared with stable nonproblem drinkers, late-onset problem drinkers at baseline were more likely to report incipient problems, heavier alcohol consumption, greater friend approval of drinking, more reliance on avoidance coping strategies, were more likely to smoke, and were less likely to have acute medical conditions that could potentially be complicated by alcohol consumption. Contrary to expectation, life stressors did not predict drinking problem onset. However, compared with stable nonproblem drinkers, late-onset problem drinkers were more likely to have a history of responding to stressors and negative affect with increased alcohol consumption.