Bordetella bronchiseptica fimbrial protein-enhanced immunogenicity of a Mannheimia haemolytica leukotoxin fragment

Leukotoxin produced by Mannheimia (Pasteurella) haemolytica is an important virulence factor in shipping fever pneumonia in feedlot cattle and is a critical protective antigen. In this study, the immune response to a chimeric protein generated by combining a gene fragment encoding neutralizing epitopes of M. haemolytica leukotoxin and a fimbrial protein gene (fim N) from Bordetella bronchiseptica was evaluated. The recombinant gene was cloned in a bacterial expression vector under the control of the tac promoter and expressed as a fusion protein with glutathione-S-transferase (GST) in Escherichia coli. Immunization of mice with the recombinant protein, GST-LTXFIM elicited a significantly stronger anti-leukotoxin antibody response than comparable immunizations with GST-LTX fusion proteins lacking FIM N. The GST-LTXFIM was also more stable than GST-LTX during storage at -80 degrees C, thus alleviating a stability problem inherent to leukotoxin. This chimeric protein may be a candidate for inclusion in new generation vaccines against shipping fever pneumonia.

Principles of dentofacial orthopedics

The differences in the response of patients to the same orthodontic treatment are, to a great extent, the result of variability in the direction and rate of craniofacial growth. Furthermore, there is currently little scientific evidence that the temporary improvement of skeletal relationships from orthopedic appliances will alter the craniofacial skeleton on a permanent basis. However, contemporary literature is beginning to show that certain appliances may be more effective than others at a specific point in the growth process. Timing of treatment in a patient is becoming of increased clinical importance. A review of the anatomy of palatal expansion indicates that expansion is much greater in the anterior portion of the palate, in both horizontal and vertical planes. Assessment of skeletal maturity for treatment timing and growth prediction is most commonly performed with the hand/wrist radiograph. A new method is presented which uses epiphyseal and diaphyseal widths and fusion of selected phalanges to determine the relative position of the individual on the pubertal growth curve. Skeletal maturity assessment is a traditional attempt to judge physiological development. The future of craniofacial growth assessment lies in the development of physiological measurements which are both replicable and valid and clinically feasible. The data from these studies provides information to allow better quantitative diagnosis and treatment as well as objective assessment of the treatment outcome.

Promoting the recruitment and retention of minority dental faculty: federal, state, and personal programs

There are federal programs available for both minority students and faculty. There are also private, state, and foundation funds available for minority students. The most important factor for these programs to succeed is the understanding of peoples' needs. We have to create an environment in which people are judged on their ability. At the same time we have to create an environment that rewards diversity.

X-ray diffraction of nitinol orthodontic arch wires

Superelastic mechanical behavior of nitinol alloy orthodontic wires is thought to be the result of a stress induced crystallographic transformation from austenite to martensite. The purpose of the study was to compare the SE mechanical behavior of nitinol wires to stress-induced phase changes. Eight nitinol arch wires having rectangular cross-sections were strained from 0% to 10% in tension with a mechanical testing machine. Load/extension plots were subjectively ranked for SE behavior. X-ray diffraction patterns were collected with and without 6% strain. Without strain, nitinol wires were found to be predominantly austenite with some wires containing a small amount of martensite. When strained 6%, superelastic wires demonstrated a phase transformation from austenite to martensite. XRD patterns were ranked for percent transformation and 110 peak width. Product rankings of the degree of superelasticity were positively correlated with the rank of martensitic transformation (p < 0.05). Superelasticity ranks were negatively correlated with XRD peak width ranks (p < 0.01). Increased peak width indicates greater cold work. A range of superelastic mechanical behavior and martensitic transformation is exhibited by wires currently on the market. Cold work and heat treatments are important variables to be controlled during the manufacture of nitinol products.

Ferritin stimulation of a monokine inhibitor of lipopolysaccharide-augmented myelopoiesis is ferroxidase dependent

Ferritin inhibition of myelopoiesis has been associated with intrinsic ferroxidase activity of heavy-chain ferritin and with production of a monokine inhibitor of lipopolysaccharide (LPS)-augmented monocytopoiesis. We report here that intrinsic ferroxidase activity of heavy-chain ferritin is required for stimulated production of the monokine inhibitor of LPS-augmented monocytopoiesis.

Comparative evaluation of ceramic bracket base designs

Since the initial introduction of ceramic brackets, base designs have been modified to reduce tooth damage during debonding. The purpose of this study was to compare shear and tensile bond strengths and fracture sites of four second-generation ceramic brackets: Allure IV (A) (GAC International, Inc., Central Islip, N.Y.), Ceramaflex (C) (TP Orthodontics, Inc., LaPorte, Ind.), Intrigue (I) (Lancer Orthodontics, Carlsbad, Calif.), Transcend 2000 (T) (Unitek Corp., Monrovia, Calif.), and a foil-mesh base stainless steel bracket, DynaBond II (D) (Unitek Corp., Monrovia, Calif.). Twenty brackets of each type were bonded to 100 mandibular bovine incisor teeth with Concise bonding adhesive. The samples were thermocycled for 24 hours and the brackets were debonded with an Instron universal testing machine (Instron Corp., Canton, Mass.). A modified Transcend debonding instrument was used for tensile debonding, whereas a chisel was used for shear debonding. An analysis of variance was performed with a 0.05 level of confidence. Mean shear strengths (kg/cm2) necessary to debond were 174.0 (A), 71.0 (C), 189.0 (I), 228.0 (T), and 160.0 (D). Mean tensile strengths (kg/cm2) were 27.0 (A), 26.7 (C), 51.3 (I), 56.5 (T), and 48.6 (D). Fracture sites examined with a light microscope showed no enamel damage with any of the ceramic brackets. Intrigue was the only bracket to fracture and had 30% bracket fracture in the tensile mode and 20% bracket fracture in the shear mode. The percentage of fractures at the adhesive-bracket base interface for shear and tensile modes, respectively, were 80, 100 (A); 100, 90 (C); 10, 60 (I); 60, 90 (T); and 90, 80 (D).(ABSTRACT TRUNCATED AT 250 WORDS)

Prostaglandin E (PGE) and interleukin-1 beta (IL-1 beta) levels in gingival crevicular fluid during human orthodontic tooth movement

The purpose of this study was to examine gingival crevicular fluid (GCF) levels of two potent bone resorbing mediators, prostaglandin E (PGE) and interleukin-1 beta (IL-1 beta), during human orthodontic tooth movement. The study included 10 patients, each having one treatment tooth undergoing orthodontic movement and a contralateral control tooth. The GCF was sampled at control sites and treatment (compression) sites before activation and a 1, 24, 48, and 168 hours. Prevention of plaque-induced inflammation allowed this study to focus on the dynamics of mechanically stimulated PGE and IL-1 beta GCF levels. The PGE and IL-1 beta levels were determined with radioimmunoassay. At 1 and 24 hours, mean GCF IL-1 beta levels were significantly elevated at treatment teeth (8.9 +/- 2.0 and 19.2 +/- 6.0 pg, respectively) compared with control teeth (2.0 +/- 1.1 pg, p = 0.0049, and 2.9 +/- 1.0 pg, p = 0.0209, respectively). The GCF levels of PGE for the treatment teeth were significantly higher at 24 and 48 hours (108.9 +/- 11.9 and 97.9 +/- 7.3 pg) than the control teeth (61.8 +/- 7.2 pg, p = 0.0071, and 70.8 +/- 7.4 pg, p = 0.0021, respectively). The GCF levels of PGE and IL-1 beta remained at baseline levels throughout the study for the control teeth, whereas significant elevations from baseline in GCF IL-1 beta (24 hours) and PGE levels (24 and 48 hours) were observed over time in the treatment teeth (p < or = 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Mandibular condyle position: comparison of articulator mountings and magnetic resonance imaging

This study evaluated the reliability of jaw positions, the existence of distinct jaw positions, and condyle-disk-fossa relationships in a symptom-free population by using articulator mountings and magnetic resonance imaging (MRI). The subjects examined included 28 men, 22 to 35 years of age, all having Angle Class I molar relationships and no discernible TMJ dysfunction. Records taken included the following: an axiographic face-bow to locate retruded hinge axis position, an interocclusal registration of retruded position (RE), a series of interocclusal registrations for centric occlusion (CO), a leaf gauge-generated centric relation (CR), a series of interocclusal registrations for CR, and MRI. The mandibular position indicator of the SAM articulator (Great Lakes Orthodontics, Ltd., Tonawanda, N.Y.) was used to determine reliability and existence of distinct jaw positions. Magnetic resonance imaging also evaluated jaw positions and anatomic relationships. The results indicate: (1) The articulator analysis of CO and CR is statistically replicable. (2) A distinct jaw position could be demonstrated for CO that was separate from RE and CR. It was not possible to discriminate between RE and CR. (3) Condylar concentricity was observed in half of the sample and remained consistent in RE, CO, and CR. (4) Of the sample 13% demonstrated anteriorly displaced disks that were not influenced by posterior condyle placement. (5) The clinical concept of treating to CR as a preventive measure to improve disk-to-condyle relationships was not supported by this study.

Cytokine mediation of the suppressive effect of ferritin on colony-stimulating factor-1-dependent monocytopoiesis

Peptide-specific IgG from a rabbit immunized with an alanine-lysine-proline-arginine ((ALA1)-tuftsin) containing 14-mer "ferritin" peptide neutralized rat liver ferritin inhibition of in vitro CSF-1-dependent monocytopoiesis. Antiferritin IgG similarly neutralized the inhibitory effect of ferritin but did not neutralize peptide inhibition of the in vitro myelopoietic response. No cross-reactivity between the respective antibodies and Ag was detected either by Western immunoblot or by competitive ELISA. Depletion of adherent cells before marrow cell culture significantly reduced the inhibitory effect of ferritin but did not influence peptide inhibition of CSF-1-stimulated colony formation. Adherent marrow cells and P388D1 cells treated with both CSF-1 and ferritin, but not either alone, produced inhibitory supernatant culture media that were neutralized by antipeptide but not antiferritin IgG. High resolution molecular sieve chromatography of the inhibitory adherent marrow cell and P388D1 supernatants resolved two peaks of 50 to 60 kDa and approximately 30 kDa in each. The inhibitory activity in all four peaks was neutralized by antipeptide but not antiferritin IgG. The ferritin/CSF inhibitors were not further characterized although identity with IL-6, IL-8, TNF-alpha, transforming growth factor-beta, and IFN-alpha/beta could be eliminated. The results indicate that ferritin inhibition of CSF-1-dependent monocytopoiesis is mediated by an endogenously produced inhibitor, or inhibitors, that shares antigenic similarity with the (ALA1)-tuftsin-containing 14-mer peptide and that adherent marrow cells, most likely monocytes or macrophages, produce the endogenous inhibitors in response to both CSF-1 and ferritin.

Cytokine mediation of the suppressive effect of ferritin on colony-stimulating factor-1-dependent monocytopoiesis

Peptide-specific IgG from a rabbit immunized with an alanine-lysine-proline-arginine ((ALA1)-tuftsin) containing 14-mer "ferritin" peptide neutralized rat liver ferritin inhibition of in vitro CSF-1-dependent monocytopoiesis. Antiferritin IgG similarly neutralized the inhibitory effect of ferritin but did not neutralize peptide inhibition of the in vitro myelopoietic response. No cross-reactivity between the respective antibodies and Ag was detected either by Western immunoblot or by competitive ELISA. Depletion of adherent cells before marrow cell culture significantly reduced the inhibitory effect of ferritin but did not influence peptide inhibition of CSF-1-stimulated colony formation. Adherent marrow cells and P388D1 cells treated with both CSF-1 and ferritin, but not either alone, produced inhibitory supernatant culture media that were neutralized by antipeptide but not antiferritin IgG. High resolution molecular sieve chromatography of the inhibitory adherent marrow cell and P388D1 supernatants resolved two peaks of 50 to 60 kDa and approximately 30 kDa in each. The inhibitory activity in all four peaks was neutralized by antipeptide but not antiferritin IgG. The ferritin/CSF inhibitors were not further characterized although identity with IL-6, IL-8, TNF-alpha, transforming growth factor-beta, and IFN-alpha/beta could be eliminated. The results indicate that ferritin inhibition of CSF-1-dependent monocytopoiesis is mediated by an endogenously produced inhibitor, or inhibitors, that shares antigenic similarity with the (ALA1)-tuftsin-containing 14-mer peptide and that adherent marrow cells, most likely monocytes or macrophages, produce the endogenous inhibitors in response to both CSF-1 and ferritin.

Isolation and functional studies on feline bone marrow derived macrophages

In this report, we describe an in vitro culture method for feline bone marrow cells, which yields large numbers of quiescent macrophages after 14 days of culture. The bulk of the cultured cell population consists of macrophages as assessed by morphology, macrophage specific cytochemistry, and phagocytosis. The remaining cells were lymphocytes, bone marrow stromal cells, fibroblasts and occasional polymorphonuclear leukocytes. While resting cells produced no detectable interleukin 1, stimulation with lipopolysaccharide (LPS) induced the production of biologically active interleukin 1. After 6 h LPS stimulation, mRNA for tumor necrosis factor alpha and interleukin 1 beta was detectable. The absence of mRNA in unstimulated cells indicates cultured macrophages were not activated until stimulated by LPS or plastic adherence. This approach provides a useful means to measure potential modulatory effects by virus infections or other agents upon feline macrophage gene expression.

Opposing effects of tumor necrosis factor alpha and leukemia inhibitory factor in lipopolysaccharide-stimulated myelopoiesis

Three myelopoietically active, lipopolysaccharide (LPS)-stimulated monokines, interleukin-1 alpha (IL-1 alpha), tumor necrosis factor alpha (TNF-alpha), and leukemia inhibitory factor (LIF), were tested for effect in an in vitro model for LPS-induced inflammatory murine monocytopoiesis. Neither cytokine stimulated clonal proliferation of marrow-derived progenitors; however, both IL-1 alpha and TNF-alpha enhanced macrophage colony-stimulating factor (M-CSF)-dependent colony formation. The additional progenitors stimulated by IL-1 alpha and TNF-alpha to form colonies in response to M-CSF were equivalent to the precommitment, transitional progenitors stimulated by M-CSF and bacterial LPS. In addition, the additional colonies elicited by IL-1 alpha and TNF-alpha were not additive in cultures containing both M-CSF and LPS, indicating these colonies arose from the same LPS-responsive, two-signal-dependent transitional progenitors. Leukemia inhibitory factor did not influence M-CSF-stimulated colony formation; however, LIF effected a dose-dependent inhibition of colony formation by transitional progenitors responding to combinations of M-CSF and LPS, IL-1 alpha, TNF-alpha, or an additional transitional cell costimulant, substance P. Neutralizing anti-murine TNF-alpha antibodies abrogated transitional cell colony formation stimulated by combinations of M-CSF and TNF-alpha, IL-1 alpha, LPS, or substance P but had no effect on colony formation stimulated solely by M-CSF. The results indicate that TNF-alpha may be an important positive stimulus for commitment of progenitors to the mononuclear phagocyte lineage and that TNF-alpha may be the endogenous regulator of the costimulatory effects of LPS, IL-1, and substance P. In addition, the results indicate that LIF may play an opposing negative regulatory role acting to inhibit LPS and TNF-alpha stimulation of the transitional progenitors.

Nanomolar cyclic adenosine and guanosine monophosphates stimulate macrophage colony-stimulating factor responsiveness by murine transitional progenitors

Both 3':5' cyclic adenosine monophosphate (cAMP) and 3':5' cyclic guanosine monophosphate (cGMP) stimulated colony-stimulating factor 1 (CSF-1)-dependent colony formation by murine two-signal-dependent progenitors without influencing colony formation by committed CSF-1-responsive progenitors. The stimulatory effect was optimal at 10(-9) M and did not diminish with increasing concentrations of the cyclic nucleotides. The membrane-permeating analogs dibutyryl cAMP and 8-Br-cGMP similarly augmented colony formation by the transitional progenitors at 10(-9) M; however, with increasing concentration, enhancement diminished with eventual inhibition of total colony formation at micromolar concentrations. Stimulation by the two cyclic nucleotides was mutually incompatible. The results indicate that physiological levels of extracellular cyclic nucleotides may significantly influence myelopoiesis. Furthermore, the results introduce the interesting possibility that stimulation, unlike inhibition, may be initiated through an extracytoplasmic mechanism that does not require direct activation of cytoplasmic cyclic nucleotide-dependent protein kinases.

Effects of bisphosphate treatment and mechanical loading on bone modeling in the rat tibia

Bisphosphonate treatment has been shown to decrease endosteal bone formation and increase periosteal bone apposition in the rat tibial diaphysis. This study tested the hypothesis that the increase in periosteal apposition is a compensatory attempt to maintain skeletal mass appropriate for the mechanical load. Twenty-four rats were divided into four groups. In two of the groups, one hindlimb in each rat was immobilized with a sling device to increase the mechanical load on the opposite limb. Daily injections of dichloromethylene bisphosphonate (Cl2MBP) were given at 10 mg/kg to one immobilized group and one mobile group. The other two groups were given daily injections of normal saline. Fluorescent bone labels were administered at two-week intervals. All rats were killed after ten weeks of treatment, and calcified tibial cross sections were prepared for fluorescence microscopy. Bone dimensions and periosteal and endosteal apposition rates were calculated. When compared with saline controls, Cl2MBP treatment decreased endosteal apposition rate in all tibias. Periosteal apposition rate was increased with Cl2MBP treatment in all tibias except the unloaded limb of immobilized rats. The Cl2MBP-induced increase in periosteal apposition rate was greatest in loaded limbs and was proportional to the relative amount of body weight supported.

Characterization of a neutralizing monoclonal antibody to Pasteurella haemolytica leukotoxin

Six hybridoma clones producing monoclonal antibodies (MAbs) reactive with Pasteurella haemolytica A1 leukotoxin were derived from mice immunized with leukotoxin excised from sodium dodecyl sulfate-polyacrylamide gels. Of the six MAbs, only one, Ltx-2, neutralized leukotoxin in a BL-3 cell cytotoxicity assay. MAb Ltx-2 blocked association of A1 leukotoxin to BL-3 cells, as measured by flow cytometric analysis. The epitope recognized by Ltx-2 was localized to the carboxyl half of the native protein, between residues 450 and 939, by Western immunoblot analysis of CNBr fragments. Further analysis with leukotoxin deletion proteins indicated either that the Ltx-2-reactive epitope was localized in the carboxyl portion of the leukotoxin between amino acids 768 and 939 or that this region influences MAb recognition of the epitope. MAb Ltx-2 was tested for neutralizing activity against leukotoxin produced by P. haemolytica serotypes 1 through 12. The MAb neutralized leukotoxin produced by all of the A biotype isolates (serotypes 1, 5, 6, 7, 8, 9, and 12), with the exception of serotype A2, but did not neutralize any T biotype leukotoxin tested (T3, T4, or T10). The results indicate that MAb Ltx-2 neutralizes leukotoxin by interfering with target cell association and that the MAb-specific epitope is either not present or not critical for function in the leukotoxin produced by P. haemolytica serotypes A2, T3, T4, and T10.

Pulmonary immunity in calves following stimulation of the gut-associated lymphatic tissue by bacterial exotoxin

Antibodies in serum and pulmonary lavage fluids were measured in calves following stimulation of the gut-associated lymphatic tissue (GALT) by inoculation of crude leukotoxin of Pasteurella haemolytica into the duodenum through a surgically placed catheter. Nine calves free of P. haemolytica were divided into two groups. Group 1 received an intraduodenal (ID) inoculation of leukotoxin and group 2 received an ID inoculation of phosphate buffered saline. Serum and pulmonary lavage fluids were collected weekly and assayed for antibodies specific to P. haemolytica including immunoglobulin (Ig)G, leukotoxin neutralizing antibodies (LNA), and IgA (lavage fluids only). The multiplicative increase (over baseline) in each class of antibody titer following ID inoculation of leukotoxin, the composite geometric mean increase of all antibodies together, and the composite number of the five antibody titers which increased at least fourfold were computed. Results showed that the geometric mean of each antibody titer and the two composite indices was higher in the GALT-primed groups than in the sham-primed group. The differences were statistically significant (p less than 0.05) for serum IgG and for the two composite indices. This experiment demonstrates for the first time that GALT stimulation by bacterial exotoxins results in increased pulmonary antibody levels in calves.

Differential effects of CD4+ and CD8+ cells in acute, systemic murine candidosis

Monoclonal antibody (mAb) depletion was used to assess contributions of CD4+ and CD8+ cells in resistance to systemic murine Candida albicans infection. Depletion of CD8+ cells did not influence either survival or mean survival time (MST); however, depletion of CD4+ cells significantly enhanced both survival and MST. Combined depletion of both CD4+ and CD8+ cells significantly lengthened the MST but did not enhance survival. A protective influence of CD8+ cells could be deduced but, to be manifested, required depletion of an overshadowing immunopathologic CD4+ response.

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.

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.

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.

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.

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.

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)

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.

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.

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.

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.

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.

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.

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.

A longitudinal study of anteroposterior growth changes in the palatine rugae

Palatine rugae have been used as internal dental cast reference points for quantification of tooth migration. Some, but not all, investigators have reported the medial rugal region to be stable or to show predictable change. The purpose of this study was to use the longitudinal data base of the Child Research Council of Denver to examine the anteroposterior stability of the medial rugal region. Dental casts of 20 females and 21 males with untreated normal Angle Class I occlusions were selected. Time intervals measured were: T1--primary teeth erupted, T2--earliest cast with permanent first molars erupted, T3--earliest cast with canines and pre-molars erupted, and T4--ages 16 to 22. Distinctive left and right anterior and posterior rugae which appeared on all four casts were identified, the medial ends marked, and the anteroposterior distances measured. The data were evaluated with the paired t test, repeated-measures ANOVA, and Tukey's multiple comparison procedure. From T1--T4, the medial rugal region increased 1.4 +/- 0.6 mm in females and 2.3 +/- 0.8 mm in males. Only two cases showed a trend toward stability. There were no significant differences by side. Significant increases in size occurred between T2 and T3 for females and males and between T3 and T4 for males. Analysis of these data indicates that the medial rugal region increases significantly in anteroposterior length, but not uniformly between the sexes across observation times. Such changes are characteristic of general craniofacial growth and suggest that the rugal region is responding to the differential growth of the underlying bone. Therefore, medial rugal landmarks appear not to be stable reference points for tooth migration research.

Dynorphin and related opioid peptides enhance tumoricidal activity mediated by murine peritoneal macrophages

The influence of dynorphin A (DYN) and related opioid peptides on the tumoricidal function of activated murine peritoneal exudate macrophages (PEM) was investigated. Addition of DYN to macrophage cultures previously activated with mixed alpha + beta-interferon (IFN-alpha/beta) and bacterial lipopolysaccharide (LPS) significantly enhanced their ability to lyse P815 murine mastocytoma cells in a 16 hr chromium-release assay. The effects of DYN were dependent on prior macrophage activation. Peptide subfragments of DYN were effective in a manner similar to that of the 17-amino-acid parent molecule, indicating that peptide interaction with either kappa or delta-opioid receptors on the effector cell is effective in potentiating lytic function. The involvement of opiate receptors was confirmed by inhibition of the effects of DYN and leucine enkephalin by the opioid receptor antagonist naloxone. Finally, in addition to IFN-alpha/beta-primed macrophages, DYN also augmented tumoricidal function in PEM primed for cytotoxicity by either gamma-interferon (IFN-gamma) or the calcium ionophore A23187, indicating that DYN potentiates function in activated macrophages independent of the specific mode of activation.

Implication of defamation for dental educators

Recent court decisions have indicated that in dealing with their students and colleagues, faculty must balance academic freedom and the individual right of fair consideration. It is also important for faculty and administrators to distinguish between decision-making procedures and criteria. It is quite clear from two recent United States Supreme Court cases that subjective evaluation by professional judgment is permissible as long as standard procedures of procedural due process are followed. In short, courts are more likely to review the application of the criteria than their substance.

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.