Biomedical subjects
R N Moore
Publications and source records attributed to R N Moore.
A technique for measurement of intraoral lip pressures with lip bumper therapy.
One of the reported effects of functional appliance therapy is muscular adaptation achieved through the use of vestibular shields. To develop a method for measuring these effects, 10 children with Class I molar occlusion in the late mixed-dentition stage underwent lip bumper therapy for 8 months. Semiconductor pressure transducers mounted on Tru-Tain stents in the mandibular midline and left canine areas were used to measure lip pressures with the patient at rest and during five functional exercises. Resting and speaking lip pressures for the midline transducer showed significant increases 1 month after lip bumper placement and then decreased to near or below pretreatment levels, possibly an adaptive response. Left-side resting pressures also showed a gradual decrease. In contrast, left-side speaking pressures showed no significant changes over time. The swallowing pressures were not replicable because of excessive background fluctuations. The results of this study indicate that this method has potential for improving clinical diagnosis. The preliminary data also suggest an adaptive response of lip muscles that varies according to anatomic location.
Bradykinin sensitization of colony-stimulating factor-1-responsive murine marrow progenitors to prostaglandin E. A property of the amino-terminal tetrapeptide fragment.
The active sequence in bradykinin (BK) responsible for PGE-aided inhibition of CSF-1-stimulated clonal proliferation of murine mononuclear phagocyte progenitors was determined. In total marrow cultures, BK and (D-Phe7)-BK, a specific BK antagonist, inhibited colony formation by CSF-1 responsive precursors that require two signals, CSF and LPS, for clonal proliferation. (Lys1)-BK, an inactive BK analogue with Lys substituted for the amino-terminal Arg, was inactive. Arg-Pro-Pro-Gly, the amino-terminal tetrapeptide fragment of BK, was fully capable, on a molar basis, of replacing either BK or (D-Phe7)-BK as an inhibitor. Bk, (D-Phe7)-BK, and Arg-Pro-Pro-Gly were not inhibitory for colony formation in cultures containing indomethacin or in cultures depleted of adherent marrow cells. However, in these cultures addition of 10(-9) M PGE2 fully restored inhibition of two-signal-dependent colony formation. PGE2-dependent inhibition by the three peptides was equivalent on a molar basis indicating that Arg-Pro-Pro-Gly contains the sequence responsible for this inhibitory effect of BK and is sufficient to exert PGE-dependent inhibition of two-signal-dependent colony formation. The two-signal-dependent progenitors appear to be in transition to CSF competence suggesting that BK and PGE produced in an hematopoietic environment may act together to limit the production of new macrophages by inhibiting progenitors in transition to CSF competence.
Skeletal maturation and craniofacial growth.
The purpose of this study was to assess the relevance of hand-wrist radiographs to craniofacial growth and clinical orthodontics. Serial annual cephalometric and hand-wrist radiographs and standing height measurements were obtained from a sample of 47 girls (ages 10 through 15 years) and 39 boys (ages 11 through 16 years) from the Bolton-Brush data base. Four skeletal linear measurements showing statistically significant increases were analyzed: SN, GoGn, SGo, and NMe. The hand-wrist radiographs were scored by the Tanner-Whitehouse TW2 RUS method of skeletal maturity assessment. The results of the study indicated that statural height and hand-wrist skeletal maturation in both sexes are significantly related. The children demonstrated a large variety of growth patterns, and growth spurts could not be consistently observed on an individual basis. Because of low statistical correlations, the relationship between acceleration and deceleration in growth of the specific craniofacial dimensions and statural height or skeletal maturity was not deemed clinically significant for prediction. However, it may be used as a factor for consideration in diagnosis and treatment planning of an individual case.
Measurement of intraoral muscle forces during functional exercises.
Measurements of intraoral muscle force with foil strain gauges, load cells, and pressure transducers bonded to a Tru-Tain stent and to a lip bumper appliance were tested by means of seven functional exercises in five adult subjects over a 5-day interval. The measuring devices and the functional exercises were tested for replicability and validity. Results showed that the pressure transducer was the superior measuring device with respect to size, sensitivity, thermal compensation, factory uniformity, replicability, and validity. The device most susceptible to error, on the basis of these factors, was the foil strain gauge. Of the seven functional exercises used, the pronunciation of the words "phone," "mom," and "church" and the exercise of swallowing were replicable over time. The other three exercises--chewing gum, sucking, and blowing on a straw--were determined to be unreliable in terms of replicability over time. Overall pressure values recorded were significantly higher than in previous reports. Pressure values were higher for the Tru-Tain stent than for the lip bumper.
Hematological changes in calves exposed to a mixture of lipopolysaccharide and crude leukotoxin of Pasteurella haemolytica.
The purpose of this investigation was to determine if culture supernatants of Pasteurella haemolytica containing crude leukotoxin and lipopolysaccharide (CLCL) causes disseminated intravascular coagulopathy (DIC) when injected into calves. The effect of intraduodenal (ID) exposure followed by a subsequent subcutaneous (SC) inoculation of either heat-treated or untreated CLCL was evaluated. The relative contribution of the crude leukotoxin and lipopolysaccharide (LPS) to the virulence of P. haemolytica was evaluated. One group of calves received an ID inoculation of CLCL followed two weeks later by a SC inoculation of CLCL; one group received an ID inoculation of tissue culture medium followed two weeks later by a SC inoculation of CLCL; and a third group received an ID inoculation of CLCL followed two weeks later by a SC inoculation of heat-treated CLCL. Hematological parameters used to evaluate DIC included white cell count, platelet count, neutrophil number, fibrinogen, fibrin degradation products, one stage prothrombin time (OSPT), activated partial thromboplastin time, body temperature and clinical signs. Each parameter was measured in calves at 0, 2, 4, 6, 12 and 24 h following the SC inoculation of CLCL. Each group had significant changes over time in all parameters except body temperature. Calves that received a SC inoculation of heat-treated CLCL had smaller changes in all parameters except OSPT compared to the other groups. Results suggest that the LPS and leukotoxin of P. haemolytica exert additive effects on the coagulation cascade and number of peripheral leukocytes, and that the ID inoculation of CLCL does not affect the response of calves to a SC inoculation of toxin.
Neurotensin regulation of macrophage colony-stimulating factor-stimulated in vitro myelopoiesis.
Neurotensin, at less than or equal to 10(-9) M, in the presence of an optimal concentration of macrophage CSF (CSF-1), stimulated a dose-dependent enhancement of colony formation by murine marrow-derived mononuclear phagocyte progenitor cells. The additional colonies arose from the cell cycle and Ia Ag-positive subpopulation previously identified as two-signal-dependent progenitors. Two-signal colony formation diminished when the peptide was added at concentrations greater than 10(-9) M. Neurotensin binds specifically to two distinct receptors, a high affinity receptor (KD approximately 10(-9) M) and a lower affinity (KD approximately 10(-7) M) receptor identified as the tuftsin receptor. Rat liver ferritin and an inhibitory tuftsin analog. (ALA1)-tuftsin, which inhibit two-signal colony formation stimulated by tuftsin and tuftsin-like peptides in combination with CSF-1, did not inhibit colony formation stimulated by CSF-1 and 10(-9) M neurotensin. Both inhibitors, however, reversed the loss of two-signal colony growth in the presence of higher neurotensin concentrations. Neurotensin fragment 1-6, unlike ferritin and (ALA1)-tuftsin, inhibited two-signal colony formation stimulated by 10(-9) M neurotensin. However, like ferritin and (ALA1)-tuftsin, fragment 1-6 permitted full expression of two-signal colony formation in the presence of CSF-1 and 10(-7) M neurotensin. The data indicated that occupancy of both receptors at neurotensin concentrations greater than 10(-9) M might be responsible for the diminished progenitor response. The data further support a potential role for neurotensin as an inflammatory mediator. In addition to direct effects on mature phagocytic leukocytes, neurotensin, at least in vitro can influence the production of new mononuclear phagocytes.
Calcium ion involvement in the action of Pasteurella haemolytica leukotoxin.
The influence of Ca2+ ions on the cytotoxic activity of Pasteurella haemolytica leukotoxin was investigated. The divalent cation influenced the cytotoxic effect of the leukotoxin for sensitive BL-3 target cells, but its absence did not eliminate cytotoxicity. In short-term 1-h assays using neutral red uptake as a measure of cell viability, depletion of Ca2+ either by exhaustive dialysis or by addition of the Ca2+ chelators EDTA and EGTA eliminated the cytolytic effect of low doses of the toxin. Addition of Ca2+ to target cell cultures depleted of the divalent cation restored the cytolytic effect of the leukotoxin. Prolonged exposure of the BL-3 cells to the toxin abrogated the protective effect of EDTA and EGTA. Cell death measured by uptake of neutral red, exclusion of trypan blue and 51Cr release indicated that protection observed in the absence of free Ca2+ was temporary. Toxin-induced cytolysis equivalent to that observed in the presence of Ca2+ occurred following the initial 2-h exposure. In addition, verapamil, a Ca2+ channel blocker, prevented cell death during 1-h cytotoxicity assays. The protection afforded by verapamil was dose-dependent and was influenced by the concentration of Ca2+ in the buffer medium. The results suggest that Ca2+ positively influences the rapid initial phase of cell death resulting from exposure to the toxin, but is not required for the entirety of the cytolytic process.
The accuracy of measuring condylion location.
In locating condylion (Co), clinicians have used cephalograms in maximum mandibular opening to provide a clearer image of the condyle. The purpose of this study was to evaluate the accuracy of identifying condylin on a sample of open and closed mouth cephalograms of 20 patients. Five orthodontists traced each mandibular outline and located condylion and the tip of the mandibular incisor (I). The incisor tip was assumed to be relatively interpretable and served as an internal control. The differences between the open and closed positions in the horizontal and vertical components of condylion relative to the mandibular plane or in the length Co-Gn were not statistically significant. The absolute deviation around condylion was significantly different (p = 0.007), but the average absolute deviation of condylion in the open position was only 0.5 mm less than condylion in the closed position. Statistically significant differences also occurred in the means of the vertical component of the incisor tip (p = 0.002), the length Gn-I (p = 0.006), and the absolute deviation of incisor tip (p = 0.004). These results indicate that the open mouth method does not significantly change the location of condylion. It does increase the accuracy of landmark identification, but this increased accuracy on the average is not clinically significant.
Vertical and horizontal components of functional appliance therapy.
Disocclusion of the teeth has been postulated to have a deregulating or promoting influence on mandibular growth. The clinical effects of disocclusion were evaluated with a prospective pilot study of 16 children with mixed dentition who wore either a maxillary Hawley biteplane or the functional regulator of Fränkel. The pilot study was used to assess individual variations to establish the feasibility of a larger, more statistically valid investigation. The biteplane was used to evaluate the effects of vertical mandibular displacement on craniofacial growth. The Fränkel regulator was used to evaluate the effects of both vertical and horizontal mandibular displacement. The relationships between patient cooperation, personality characteristic, and treatment effects were also evaluated. After 9 months of treatment, the biteplane group had an increase in the mandibular plane angle with little or no horizontal mandibular growth and tendency toward an interior open bite. This was deemed to be clinically detrimental and the biteplane therapy was discontinued. The results of this study are presented to aid the clinician in his or her decision to use biteplane therapy. In the biteplane group, the bite opening was associated with molar, and not incisor, extrusion. Though the biteplane group had primarily a vertical increase in the length of the lower third of the face, the Fränkel group had a combination of anterior and inferior mandibular growth. In both groups, the mandibular incisor usually moved anteriorly. The maxially incisor usually moved labially in the biteplane group and lingually in the Fränkel group, although exceptions were in both groups. Correlation coefficients between self-esteem, compliance, and cognitive level were not statistically significant. These findings suggest that a constant protracting force on the mandible, rather than bite opening only, may be necessary for increasing mandibular length. Thus the biteplane should only be used to increase the vertical dentoalveolar and facial heights in patients with normal anteroposterior maxillary-mandibular relationships.
Induction of pulmonary antibodies to Pasteurella haemolytica following intraduodenal stimulation of the gut-associated lymphatic tissue in cattle.
The induction of pulmonary antibodies to a bacterial antigen following intraduodenal (D) stimulation of the gut-associated lymphatic tissue (GALT) was investigated. Six calves were divided into two groups of three calves each. The GALT-primed calves received an ID dose of live Pasteurella haemolytica A1 followed by a subcutaneous (SC) dose of killed P. haemolytica. The sham-primed calves received an ID dose of phosphate-buffered saline solution (PBSS) followed by a SC dose of killed bacteria. Serum and pulmonary lavage fluids were collected weekly from each calf and assayed for titers of leukotoxin neutralizing antibodies (LNA), as well as IgG and IgA (lavage fluids only) to P. haemolytica. The GALT-primed calves responded to the ID stimulation by bacteria with increased serum IgG. The sham-primed calves had no change in antibody titers following ID stimulation. The GALT-primed calves had increased serum IgG, lavage IgG and IgA and increased LNA titers in both lavage fluids and serum following the SC dose of killed bacteria. The sham-primed calves demonstrated only an increase in serum IgG following the SC inoculation. A challenge study to evaluate if antibodies induced by GALT stimulation could reduce pulmonary lesions was performed using six calves divided into two groups. One group received an ID dose of P. haemolytica followed two weeks later by a SC dose of killed P. haemolytica. The sham vaccinated calves received an ID dose of PBSS followed in two weeks by a SC dose of killed bacterin. Calves were challenged by an intrapulmonary dose of live P. haemolytica A1 eleven days after the SC inoculation.(ABSTRACT TRUNCATED AT 250 WORDS)
Bradykinin sensitization of CSF-1-responsive murine mononuclear phagocyte precursors to prostaglandin E.
Bradykinin (BK) inhibited clonal proliferation of CSF-1-stimulated mononuclear phagocyte precursors derived from murine marrow. This inhibitory effect of BK was restricted to the subpopulation of precursors that required two signals, CSF-1 and LPS, for clonal proliferation. No effect was observed on stimulated colony formation by precursors that responded solely to the addition of CSF-1. Inhibition of colony formation by the two signal-dependent precursors required the presence of adherent marrow cells and was mediated by endogenously produced PG. Although evidence was obtained indicating that BK augmented PG production by adherent cells, an additional effect of BK appeared to be a significant sensitization of the two signal-dependent precursors to inhibition by PGE.
Substance P augmentation of CSF-1-stimulated in vitro myelopoiesis. A two-signal progenitor restricted, tuftsin-like effect.
The inflammatory neuropeptide substance P acted as a costimulant for macrophage CSF-1-induced clonal proliferation of murine marrow-derived two signal-dependent mononuclear phagocyte progenitors. Substance P had no effect on clonal proliferation by progenitors responding solely to CSF-1. Substance P fragment 2-11 had no costimulatory activity; however, SP fragment 1-4 retained the full activity of the parent undecapeptide. Fragment 1-4 (ARG-PRO-LYS-PRO), a peptide containing a PRO residue between two positive charges, is a tuftsin-like (THR-LYS-PRO-ARG) tetrapeptide, and tuftsin exerted an identical costimulatory effect. Substance P, SP:1-4, and tuftsin were optimally effective as costimulants at 10(-7) to 10(-6) M. (ALA1)-tuftsin, an inhibitory analog of tuftsin, was a potent negative regulator of two signal-dependent colony formation. (ALA1)-tuftsin at concentrations less than or equal to 10(-9) M exerted dose-dependent inhibition of the positive effects of optimal concentrations of all of the co-stimulants tested, including bacterial LPS. The inhibitory tetrapeptide was equivalent in activity to ferritin, an established inhibitor of two signal-dependent colony formation. The results indicated that SP may influence myelopoiesis in addition to its other inflammatory and immunopotentiating properties. In addition, a potentially valuable modulator of SP and LPS responses in this system, (ALA1)-tuftsin, was identified.
Bonding orthodontic acrylic resin to enamel.
Bonded acrylic orthodontic appliances are a recent alternative to banded methods. However, the physical properties demonstrated by bonding adhesives at the acrylic-enamel interphase have not been well documented. The purpose of this study was to use a laboratory testing model to evaluate the ultimate shear and tensile strengths and fracture sites of five bonding adhesives: unfilled (Bracketbond and Genie); filled (Unite, Excel, and Concise). One hundred bovine mandibular incisors were embedded in dental stone, labial surfaces ground flat for uniform acrylic-enamel adaptation, and stored in modified Fusyama's artificial saliva. Twenty 7-mm diameter acrylic cylinders were bonded in each group. Ten samples from each group were tested for shear strength and ten for tensile strength with an Instron testing machine. Bonding adhesive retained on the cylinder was measured by means of a Bioquant digitizer. Scanning electron microscopy was used to analyze fracture sites. The results showed that the percentage of bonding adhesive that remains on the acrylic surface after fracture is decreased by the addition of inorganic fillers to the adhesive and the use of separate liquid resin sealants, and is increased by the use of plastic bracket primers and bonding adhesives that are chemically similar to methylmethacrylate. Few significant differences in shear and tensile strengths were found among the bonding adhesives. Unfilled bonding adhesives cause less enamel damage and are indicated for clinical bonding of acrylic orthodontic appliances to enamel.
Predoctoral and continuing education in orthodontics. Opinions of Nebraska Alumni.
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Enhanced killing of Candida albicans by murine macrophages treated with macrophage colony-stimulating factor: evidence for augmented expression of mannose receptors.
The effect of macrophage colony-stimulating factor (CSF-1) on killing of Candida albicans by murine peritoneal macrophages was determined. The killing capacity of resident peritoneal macrophages was unaffected by CSF-1. However, proteose-peptone-elicited peritoneal exudate macrophages that had been pretreated with CSF-1 (greater than or equal to 1000 U/ml) for 24 or 48 hr exhibited a significantly enhanced capacity to kill C. albicans. CSF-enhanced killing appeared to be independent of endogenously produced interferon-alpha/beta (IFN) in that enhancement by these two agents differed with regard to onset of the effect, target cell responsiveness, and duration of augmented killing. In addition, a highly specific anti-IFN antiserum that totally neutralized IFN augmentation of candidacidal activity had no effect on CSF-induced enhancement. Evidence was obtained indicating that CSF, unlike IFN, augmented mannose-inhibitable binding and ingestion of C. albicans, suggesting that augmented expression of mannose-receptors by CSF-treated macrophages was at least partially responsible for the enhanced killing.
Biosynthetic thiolase from zoogloea ramigera. I. Preliminary characterization and analysis of proton transfer reaction.
The biosynthetic thiolase, from Zoogloea ramigera, involved in generation of acetoacetyl-CoA for poly-beta-hydroxybutyrate synthesis, has been prepared pure in quantity for initial structural characterization of this homotetrameric enzyme. Edman degradation provided the sequence of the NH2 terminal 25 residues and an active site cysteine-containing nonapeptide labeled on stoichiometric inactivation by iodoacetamide. Both sequences were used to align the encoding DNA sequence of the cloned gene as described in an accompanying paper. Synthetic analogs of acetoacetyl-S-CoA, modified in the CoA moiety, were prepared and tested, and acetoacetyl-S-pantetheine 11-pivalate 1 was shown to have a kcat/Km of 6.4 X 10(6) M-1 s-1, comparable to the kcat/Km of 2 X 10(7) M-1 s-1 for acetoacetyl-S-CoA. The pantetheine pivalate group facilitates nonaqueous synthetic manipulations and may be generally useful as a CoA replacement. We have also prepared the carba analog of 1, with CH2 replacing S, to yield a beta-diketone analog 10 of acetoacetyl-S-CoA and the corresponding methyl ketone analog 9 of acetyl-S-CoA. These analogs have been used to prove the ability of Z. ramigera thiolase to catalyze proton abstraction from the C-2 methyl group of the acetyl portion of substrate in a transition state separate from C-C bond formation. NMR studies in D2O show exchange only when condensation is possible. Further studies with [2-3H]acetyl-CoA show there is neither pre-equilibrium washout nor detectable kH/kT expressed in turnover and provide no evidence for a discrete acetyl-CoA C-2 carbanion or a nonconcerted reaction.