Arginine 206 of the C5a receptor is critical for ligand recognition and receptor activation by C-terminal hexapeptide analogs

C5a is a 74-amino-acid glycoprotein whose receptor is a member of the rhodopsin superfamily. While antagonists have been generated to many of these receptors, similar efforts directed at family members whose natural ligands are proteins have met with little success. The recent development of hexapeptide analogs of C5a has allowed us to begin elucidation of the molecular events that lead to activation by combining a structure/activity study of the ligand with receptor mutagenesis. Removal of the hexapeptide's C-terminal arginine reduces affinity by 100-fold and eliminates the ability of the ligand to activate the receptor. Both the guanidino side chain and the free carboxyl of the arginine participate in the interaction. The guanidino group makes the energy-yielding contact with the receptor, while the free carboxylate negates "electrostatic" interference with Arg-206 of the receptor. It is the apparent movement Arg-206 induced by this set of interactions that is responsible for activation, since conversion of Arg-206 to alanine eliminates the agonist activity of the hexapeptides. Surprisingly, activation is a nearly energy-neutral event and may reflect the binding process rather than the final resting site of the ligand.     

The North Carolina Breast Cancer Screening Program: foundations and design of a model for reaching older, minority, rural women

Breast cancer screening programs do not reach all women at the same rate. Screening mammography use varies according to sociodemographic characteristics; mammography utilization is highest among women in their fifties but then decreases with age. In North Carolina, breast cancer is a particular burden for Black and lower-income women. Black women are more likely to be diagnosed with late stage disease, and their rate of breast cancer mortality is higher than it is for White women even though the incidence in White women is greater. Older, Black, and low-income women are less likely to obtain screening by mammography and clinical breast examination. The Black-White gap is even more pronounced among rural women, in part because they are more likely to be poor. The North Carolina Breast Cancer Screening Program (NC-BCSP) was established to increase the rate of regular mammography screening by an absolute 20% in 3 years among older Black women ages 50 and older in five rural counties in the eastern part of the state. In this paper, we describe the genesis of this comprehensive community intervention model, highlighting the behavioral science constructs, health education principles, and theories of behavioral and organizational change that form its conceptual foundation. NC-BCSP's theoretical foundations include the social ecological perspective, the PRECEDE model of health promotion, the Health Belief Model of individual change, and the "stages of change" transtheoretical model. We also review the experiences and lessons learned from two previous outreach initiatives in North Carolina that provided valuable "lessons" in the development of the NC-BCSP intervention model. In the second half of the paper, we describe the actual NC-BCSP interventions, activities, and evaluation tools, citing specific examples of how the underlying theories are implemented. NC-BCSP's goal goes beyond individual behavior change to raise low mammography screening rates among Black women in rural North Carolina. Its ultimate objective is to create linkages across agencies, and between agencies and communities, that will endure after the research project ends.     

Localization of atrial natriuretic peptide receptors in the rat tongue and hard palate

The effect of a naturally occurring plant phenolic constituent (the acylphloroglucinol derivative, jensenone, derived from Eucalyptus jensenii) on the food intake of two folivorous marsupials, the common ringtail (Pseudocheirus peregrinus) and the common brushtail possum (Trichosurus vulpecula) was studied. When fed diets containing varying concentrations of jensenone, both species regulated their intake of jensenone so as not to exceed a ceiling intake. This ceiling was about twice as high for common ringtails as for common brushtails from northern Australia. Southern populations of common ringtails showed greatly reduced capacities to tolerate jensenone. When common brushtails were injected (0.5 mg.kg-0.75 body mass) with ondansetron (a selective antagonist of serotonin 5HT3 receptors), they ate significantly more jensenone than animals injected with physiological saline. The same pattern was observed when common ringtails were fed diets containing both jensenone and ondansetron (0.0035 mg.g-1 wet mass of diet). Ondansetron injection had no effect on food intake when the food did not contain jensenone while the addition of higher doses of ondansetron to diets of common ringtails very slightly reduced food intakes of a non-jensenone diet. When common brushtails were given 50 mg of jensenone by gastric lavage, their average subsequent intake of dietary jensenone matched the difference between the daily threshold and the dose given, although the response of individuals was highly variable. Lavage with water alone had no effect on subsequent jensenone intake compared with the pre-dose period. We interpret these results as evidence that the antifeedant effects of jensenone and related compounds are partly mediated by serotonin action on 5HT3 receptors most likely via "nausea" to condition a food aversion.     

Isolation and characterization of a novel facultatively alkaliphilic Nitrobacter species, N. alkalicus sp. nov

BACKGROUND: The American College of Rheumatology (ACR) established criteria to discriminate among patients with seven types of vasculitis. Although designated as "classification criteria" for research, these criteria are often used for diagnosis. OBJECTIVE: To examine the operating characteristics of the 1990 ACR classification criteria in the diagnosis of Wegener granulomatosis, giant-cell arteritis, polyarteritis nodosa, and hypersensitivity vasculitis. DESIGN: Prospective cohort study. SETTING: University medical center and Veterans Affairs medical center. PATIENTS: 198 consecutive patients referred to rheumatologists for evaluation of possible vasculitis. Measurements: Blinded chart audits were done to classify patients according to the 1990 ACR classification criteria for Wegener granulomatosis, polyarteritis nodosa, giant-cell arteritis, and hypersensitivity vasculitis on the basis of the patients' initial presentation. Chart audits done 2 to 8 months after baseline provided the patients' final diagnoses, which were considered the gold standard, as in the development of the ACR criteria. Test operating characteristics of the ACR classification criteria were calculated according to 2 x 2 tables for the entire cohort and for only the patients with a final diagnosis of vasculitis. RESULTS: Vasculitis was diagnosed in 51 (26%) patients. Thirty-eight (75%) of 51 patients with vasculitis and 31 (21%) of 147 patients without vasculitis met ACR criteria for one or more types of vasculitis. The positive predictive values for the four vasculitides according to ACR criteria were 17% to 29% for the entire cohort and 29% to 75% for only the patients with a final diagnosis of vasculitis. CONCLUSION: The 1990 ACR classification criteria function poorly in the diagnosis of specific vasculitides.     

Post-craniectomy intracranial hypotension: potential impact on rehabilitation

The process of active dissociation or "DNA clearing" of not covalently binding agents from DNA in living HeLa cells was shown by the flow cytometry technique. The vital fluorescent bisbenzimidazole dye Hoechst 33342, which binds tightly but not covalently to DNA in a minor groove, was used as a basic model to study the interaction of not covalently binding agents with DNA. In this paper, we continue to analyse the "DNA clearing" process in the living fibroblasts of different rodent species (mouse, rat, Chinese hamster). The obtained data suggest that the processes of active dissociation or "DNA clearing" of Hoechst 33342 have some common features in all investigated mammalian cells. Nevertheless, some differences in the process were found in these lines. The role of nucleotide excision repair genes in the process of DNA clearing was not established.     

Acute heavy alcohol intake increases silent myocardial ischaemia in patients with stable angina pectoris

PURPOSE: The purpose was to determine tumor neovascularisation via colour-coded Doppler (duplex) sonography and the "power mode", both visually and quantitatively, by means of videodensitometry. MATERIAL AND METHODS: 6 VX2 tumours of 4 to 11 mm size were implanted in 4 rabbits at various sites. The colour-coded duplex sonography and the new sonographic power technique were tested before and after having injected a new contrast medium (SH U 616A). RESULTS: If no contrast medium was injected, tumour neovascularisation was identified in only 50% of the cases. Injection of contrast medium increased signal intensity three to fourfold with all examined tumors. Combined use of the sonographic method by the power technique with injection of contrast medium is outstandingly suitable for tumor vessel imaging even of small tumors, as these initial results seem to show. CONCLUSION: If these results are corroborated by further studies, contrast-medium supported sonographic technique may possibly become established as an alternative method to other imaging procedures.     

A clinical retrospective evaluation of FA/HA coated (Biocomp) dental implants. Results after 1 year

The development of ovulation-inducing drugs has enabled clinicians to more effectively treat the hypothalamic, pituitary, and ovarian abnormalities resulting in infertility. Pregnancy rates have been improved with the use of agents such as clomiphene citrate (CC), human menopausal gonadotropin [hMG or follicle-stimulating hormone (FSH) preparations], with gonadotropin-releasing hormone (GnRH) and its analogs, stimulating the development of multiple ovarian follicles and increasing the number of fertilizable oocytes. The use of these drugs is not without certain detrimental or "toxic" consequences. The negative effects from superovulation can occur during follicle development, decreasing the number of healthy oocytes and embryos capable of leading to viable pregnancy. Ovulation induction can lead not only to higher incidences of spontaneous abortions, and multiple and ectopic pregnancies, but also to poor pregnancy rates, due, in part, to asynchrony between embryonic development and the uterine environment. Diseases such as ovarian hyperstimulation syndrome (OHSS), resulting in the secretion of supraphysiologic levels of estradiol, can lend to severe health complications, possibly requiring hospitalization. Most drugs used for ovulation induction can lead to OHSS. Although incidences of OHSS following CC use are less frequent, CC has been associated with hot flushes, multiple gestations, visual disturbances, cervical mucus abnormalities, and luteal phase deficiency. Finally, there are reports that link any or all of the ovulation-inducing drugs with a higher incidence of ovarian and breast cancer, however, a cause-effect relationship has yet to be proven.     

Presence of mind: a reaction to Thomas Sheridan's "Further musings on the psychophysics of presence."

An operator's sense of remote presence during teleoperation or use of virtual environment interfaces is analyzed as to what characteristics it should have to qualify it as an explanatory scientific construct. But the implicit goal of designing virtual environment interfaces to maximize presence is itself questioned in a second section in which examples of human-machine interfaces beneficially designed to avoid a strong sense of egocentric presence are cited. In conclusion, it is argued that the design of a teleoperation or virtual environment system should generally focus on the efficient communication of causal interaction. In this view the sense of presence, that is of actually being at the simulated or remote workplace, is an epiphenomena of secondary importance for design.     

An efficient method to detect calcitonin mRNA in normal and neoplastic rat C-cells (medullary thyroid carcinoma) by in situ hybridization using a digoxigenin-labeled synthetic oligodeoxyribonucleotide probe

We report here an efficient and rapid method for the specific detection of calcitonin in tumor C-cells of medullary thyroid carcinoma (MTC). This occasionally aggressive tumor arises from the endocrine thyroid C-cells. Its principal marker is calcitonin, the predominant C-cell secretion, which is detected in patients and in our animal model by radioimmunoassay of the plasma, as well as by immunohistochemistry of thyroid tissues. Although calcitonin is easily detectable in normal C-cells, its content is greatly reduced in tumor cells owing to the disappearance of the secretory granules that store the mature peptide. This finding suggests cell dedifferentiation correlated with an increasing aggressivity of the tumor. We therefore developed a rapid detection of calcitonin mRNA by in situ hybridization on routine paraffin sections, using a synthetic oligodeoxyribonucleotide probe labeled with digoxigenin-dUTP. The reaction was detected with an anti-digoxigenin antibody conjugated with alkaline phosphatase, and the enzyme catalyzed the appearance of a dark blue color. The signal was exclusively restricted to the normal, hyperplastic, and tumor C-cells. It was specific, as increasing concentrations of the unlabeled oligonucleotide led to progressive disappearance of the reaction. Its sensitivity was slightly diminished as compared with corresponding frozen sections, but the intensity of the signal was quite acceptable. High levels of calcitonin mRNA were found in all normal and hyperplastic C-cells. They were increased in most of the tumor MTC cells, which did not correlate with the amount of intracellular peptide stores but explained the abnormally high basal levels of circulating calcitonin of the tumor-bearing rats. ISH is therefore of greater value than ICC for an early anatomopathological detection of this tumor. Our data show that the tumor cells are not "dedifferentiated." They only lack the granular compartment storing the mature peptide before exocytosis, but CT biosynthesis and the rest of the secretory process seem to be complete. Our results suggest that factors expressed in malignant C-cells affect basic cell mechanisms involved in the storage of the mature calcitonin, rather than the expression of the CALC gene.