Structural organization of yeast and mammalian mediator complexes.

Structures of yeast Mediator complex, of a related complex from mouse cells and of thyroid hormone receptor-associated protein complex from human cells have been determined by three-dimensional reconstruction from electron micrographs of single particles. All three complexes show a division in two parts, a "head" domain and a combined "middle-tail" domain. The head domains of the three complexes appear most similar and interact most closely with RNA polymerase II. The middle-tail domains show the greatest structural divergence and, in the case of the tail domain, may not interact with polymerase at all. Consistent with this structural divergence, analysis of a yeast Mediator mutant localizes subunits that are not conserved between yeast and mammalian cells to the tail domain. Biochemically defined Rgr1 and Srb4 modules of yeast Mediator are then assigned to the middle and head domains.

Relationships between radiographic alveolar bone height and probing attachment level: data from healthy post-menopausal women.

OBJECTIVE: To determine the cross-sectional and longitudinal relationships between radiographic alveolar bone height and probing attachment level in a population of healthy postmenopausal women. MATERIALS AND METHODS: The 81 patients in this report were part of a prospective estrogen replacement interventional study. All patients were in good oral health at entry and received annual oral prophylaxis as part of the study. Standard probing measurements were made with a pressure sensitive probe at 6 sites on each tooth. Vertical bitewing radiographs were digitized, and 6 linear measurements corresponding to probing-site measurements were made from the cementoenamel junction to the alveolar crest. These procedures were performed at baseline and at annual intervals for three years. Data were analyzed both by site and by patient. RESULTS: Moderately strong correlations were found between cross-sectional measurements of probing attachment height and radiographic bone height. Correlations were stronger for patient data (r=0.44-0.61) than for site data (r=0.19-0.36). No relationships were found between longitudinal changes in alveolar bone height and attachment level in either the site data (r=-0.10-0.04). or the patient data (r=-0.005-0.10). CONCLUSION: Healthy patients may experience sporadic, temporary changes in attachment level or alveolar bone height which are resolved without one affecting the other.

Alveolar bone height and postcranial bone mineral density: negative effects of cigarette smoking and parity.

BACKGROUND: Our objective was to test the association between cemento-enamel junction, alveolar-crest distance (CEJ-AC, as measured on digitized vertical bite-wing radiographs) and postcranial bone mineral density (BMD) relative to clinical, dietary, and demographic variables. METHODS: Data were collected in a cross-sectional study of 134 postmenopausal women. CEJ-AC distances were determined from digitized vertical bite-wing radiographs. Lumbar spine and proximal femur BMDs were determined from dual-energy x-ray absorptiometric scans. Correlation analysis and Student t tests were used to identify those variables most associated with CEJ-AC distance. The selected variables were modeled with a backward stepwise regression analysis, with CEJ-AC distance as the dependent variable. RESULTS: Parity (number of pregnancies to term), cigarette smoking, and the interaction of lateral spine BMD with cigarette smoking were independent predictors of CEJ-AC distance (P < or =0.05). Statistical models containing these variables accounted for 19% of the variation in CEJ-AC distances. CONCLUSIONS: CEJ-AC distance in postmenopausal women is the result of a complicated interaction of many effects, including but not limited to, parity, cigarette smoking, and skeletal BMD.

Comparison of morphological measurements extracted from digitized dental radiographs with lumbar and femoral bone mineral density measurements in postmenopausal women.

BACKGROUND: We set out to determine whether morphologic measurements extracted from digitized images of bite-wing radiographs correlated with lumbar and femoral bone mineral density (BMD) measurements in 45 postmenopausal women who had no or only mild periodontal disease (no probing depths >5 mm). METHODS: Lumbar spine and femoral BMDs were determined by dual-energy x-ray absorptiometry. Vertical bite-wing radiographs were taken and digitized. Crestal and apical regions of interest (ROIs) were drawn on the digital images of the maxillary and mandibular alveolar bone on the patient's right and left sides. For each patient, a single morphologic measurement was made for each of 8 ROIs. Correlation analysis was performed to determine the strengths of the relationships between the morphologic measurements made at the 8 locations and between these morphologic measurements and BMD measurements. RESULTS: The correlations (r) between the morphologic operator (MO) measurements and lumbar spine and femoral BMDs were weak (mean r = 0.02, range = 0.32 to -0.26) and not statistically significant, with no clear trends discernible. Correlations between MO measurements made at the 8 alveolar sites were also weak (mean r = 0.05, range = 0.35 to -0.38) and not statistically significant. CONCLUSIONS: The MO measurements used in this study were weakly correlated with lumbar spine and femoral BMDs, with no clear trends discernible in this population of postmenopausal women with no or mild periodontal disease.

The effect of region of interest variations on morphologic operations data and gray-level values extracted from digitized dental radiographs.

OBJECTIVE: To determine the correlations among morphologic operations (MO) values and the correlations among gray-level values for regions of interest (ROIs) placed at various locations on digital images of alveolar bone for 45 patients. STUDY DESIGN: As part of a larger study, up to 7 vertical bite-wing radiographs were taken and digitized for each of 45 patients. Sets of 2 rectangular ROIs were placed on the digitized images of interdental alveolar bone at 4 locations for each patient. The ROIs (1 crestal and 1 apical) were placed between second premolars and first molars in all 4 dental quadrants. Gray-level values were measured, and MO analysis was performed on each ROI. Descriptive statistics were calculated and correlations determined. RESULTS: Paired correlations (such as apical vs crestal, left vs right, maxillary apical vs mandibular apical) of MO values were weak (r = 0.01-0.21), but corresponding correlations for gray-level values were relatively strong (r = 0. 60-0.92). CONCLUSION: MO values varied with ROI location considerably more than did gray-level values. Additionally, ROI size and shape apparently affected MO data. Accurate placement and documentation of ROIs appear to be critical considerations in analyses that use MOs.

Relationships between longitudinal changes in radiographic alveolar bone height and probing depth measurements: data from postmenopausal women.

BACKGROUND: The relationship between loss of radiographic alveolar bone height and probing attachment loss has been studied by a number of investigators, with mixed results. Recent studies have found weak correlations and have suggested that the relationship between bone loss and attachment loss is complex, perhaps because changes in bone height and attachment level are separated in time. METHODS: The 85 patients in this report were part of a prospective estrogen replacement interventional study. All patients were in good oral health at entry and received annual oral prophylaxis as part of the study. Standard probing measurements were made with a pressure-sensitive probe at 6 sites on each tooth. Vertical bite-wing radiographs were taken of each patient, radiographs were digitized, and 6 linear measurements (corresponding to probing site measurements) were made from the cemento-enamel junction to the alveolar crest. These procedures were performed at baseline and at annual intervals; this study reports results after 2 years. Data were analyzed both by individual site and by averaging identical sites from all measured teeth for each patient. RESULTS: Very weak direct relationships between change in alveolar bone height and change in attachment level were found in both the site data (r2=0.0022; P = 0.189) and the patient average data (r2=0.031; P= 0.104). CONCLUSIONS: The changes in these patients were probably due to systemic changes in bone health rather than to periodontal disease. However, the weak correlations between changes in attachment level and bone height are similar to recent studies of periodontal disease. Our results support suggestions in the literature that the link between changes in attachment and alveolar bone height is complex, perhaps because changes in the 2 tissue types are separated by a considerable time delay.

Attachment loss with postmenopausal age and smoking.

To determine whether postmenopausal bone loss and factors associated with osteoporosis affect tooth retention, we examined vertebral and proximal femoral (postcranial) bone mineral density in relation to tooth loss and attachment loss in a cross-sectional study of 135 postmenopausal women (age range 41-70 yr). Women had at least 10 teeth and no evidence of moderate or severe periodontal disease. Full-mouth attachment loss measurements were made using a pressure-sensitive probe, and bone density was determined by dual-energy X-ray absorptiometry. Attachment loss was correlated with tooth loss (number of remaining teeth, radiologically determined), but not with vertebral or proximal femur bone density. Multivariate analysis showed current smoking (p = 0.01), years since menopause (p = 0.02) and the interaction of age and current smoking (p < 0.01), to be statistically significant predictors of attachment loss in our study population.

Efficacy of a dentifrice containing potassium nitrate, soluble pyrophosphate, PVM/MA copolymer, and sodium fluoride on dentinal hypersensitivity: a twelve-week clinical study.

The effect on dentinal hypersensitivity from the use of a dentifrice containing 5.0% potassium nitrate, 1.3% soluble pyrophosphate, 1.5% PVM/MA copolymer, and 0.243% sodium fluoride in a silica base over a twelve-week period was compared to a matching placebo dentifrice without potassium nitrate. A total of sixty-seven subjects were entered into the study, and stratified into two balanced groups according to their baseline mean thermal (threshold) temperature (Thermodontic Stimulator) and baseline mean tactile (Yeaple Probe) sensitivity scores. The two groups were randomly assigned to use either the potassium nitrate/copolymer/pyrophosphate dentifrice or the placebo dentifrice. The two groups were well balanced with regard to their mean baseline thermal and tactile sensitivity scores, sex and age. Subjects were instructed to brush their teeth twice daily (morning and evening) for one minute with their assigned dentifrice and a commercially available soft-bristled toothbrush. Dentinal hypersensitivity examinations, which included tactile sensitivity, threshold thermal sensitivity, pain thermal sensitivity, air blast, and a visual analog scale were conducted at baseline, six weeks, and twelve weeks. All examinations were conducted by the same dental examiner. After six weeks' use of their assigned products, those subjects in the potassium nitrate/copolymer/pyrophosphate dentifrice group demonstrated statistically significant improvements (p < 0.01), as compared to the placebo dentifrice, in the following parameters: 1) tactile; 2) thermal (threshold and pain); and 3) air blast. After twelve weeks' use of their assigned products, those subjects in the potassium nitrate/copolymer/pyrophosphate dentifrice group again demonstrated statistically significant improvements (p < 0.01), in tactile, thermal (threshold and pain) and air blast sensitivity, as compared to the placebo dentifrice. It was concluded from this study that a dentifrice containing 5.0% potassium nitrate, 1.3% soluble pyrophosphate, 1.5% PVM/MA copolymer, and 0.243% sodium fluoride in a silica base is a clinically effective treatment for reducing dentinal hypersensitivity.

Implementing marketing strategy (Part four).

Every organization must monitor and evaluate the performance of its marketing strategies. The health care marketer must continually develop effective measures related to outcomes so that marketing efforts can be justified and garnish the support and resources they deserve. A major task for the marketing executive for the next decade is to develop marketing strategies and prove that those strategies are being met and that they help the health care organization carry out its objective to meet its mission.

Plant transformation: a simple particle bombardment device based on flowing helium.

We observed that flowing helium at moderate pressures accelerated DNA-coated microprojectiles to velocities suitable for penetration of cells in intact plant tissues. The flowing helium principle permitted the construction of a simple and inexpensive transformation device that was easier to use than those previously described. This device provided efficient transformation of cells in soybean seedlings and other plants.

Direct hospital marketing: an idea whose time has come.

Health care marketing has arrived swiftly and with significant impact upon the hospital scene. From the early days of rejection and suspicion of only a few years ago, it has now taken its place with other hospital management functions. Still, however, hospitals have not yet reached the degree of expertise that exists in other sectors. One of the reasons why hospitals have not fully emerged to the level of marketing expertise as many of their traditional business counterparts is that many of the areas of both the science and art of marketing have not been fully developed. One such area is direct mail marketing. Presented here is an overview of the advantages and functions of hospital direct mail marketing. A variety of examples are given with a more thorough case example being provided by Lee's Summit Community Hospital in Lee's Summit, Missouri. The successful direct mail marketing campaign there should be both an inspiration and a model for success for other hospitals. Space limitations prevent the authors from some of the more exacting details of mail marketing and, of course, successful campaigns do not happen by magic. They take careful planning, strategy, and execution. They also require a coordinated organizational and human effort to be successful. But direct mail marketing does offer a potentially new arena of marketing for most hospitals. The expertise, skill, knowledge, and technology are in place. All that is really needed is the commitment on the part of the hospital leadership.

A flagging system for multichannel hematology analyzers.

A flagging system to identify blood specimens requiring a blood film review and/or differential leukocyte count is described. Its utility in avoiding unnecessary differential counts particularly in outpatients is given. Significant reductions in workload can be anticipated without deterioration of patient care.

A critical evaluation of the manual/visual differential leukocyte counting method.

The performance of differential leukocyte counting by 73 technologists and technicians working in 5 different laboratories in a large medical center was evaluated. Good correlation with the reference method was found for neutrophils, normal lymphocytes, and eosinophils. More variability was noted in the estimation of stab neutrophils and variant (atypical) lymphocytes and monocytes. The sensitivity of this method for clinically important conditions ranged from 100% to 34%, depending upon the abnormality.

Morphologic alterations in early acid-induced epithelial injury of the rabbit esophagus.

To arrive at a basic understanding of the pathogenesis of reflux esophagitis, we developed an acute experimental model in the rabbit for studying the early lesion. Acid was perfused in vivo into the lower esophagus while potential difference was monitored intermittently. At varying degrees of potential difference decline, indicating epithelial injury, the esophageal stratified squamous epithelial tissue was removed for morphologic studies and in vitro electrophysiologic and transport studies. At 50 per cent reduction in potential difference, there was dilation of intercellular spaces, which when correlated with physiologic results of increased permeability indicates increased intercellular water. At 100 per cent reduction in potential difference, cells in the midepithelium were observed to be swollen and ruptured, forming vesicular spaces, midepithelial cleavages, and later early ulceration. Results of functional studies at this stage showed inhibition of sodium transport. The midepithelial site of disruption corresponds to the site of active sodium pumping out of cells in other stratified squamous epithelia. Since sodium is transported by esophageal epithelium and this function was inhibited by acid, we propose that this early morphologic lesion may be the result of damage to the sodium-transporting mechanisms of the epithelium.