Serine protease activity is essential for thrombin-induced protein synthesis in cultured human dental pulp cells: modulation roles of prostaglandin E2

Irritations and injuries to the dental pulp usually lead to different degrees of pulpal inflammation. To investigate the roles of thrombin and prostaglandins in the healing and inflammatory processes of dental pulp as well as their effects on pulpal protein synthesis, human dental pulp cell cultures were established and their protein production was measured with or without the presence of exogenous thrombin and prostaglandins. At concentrations of 1-25 U/ml, alpha-thrombin increased the protein synthesis to 1.4-2.3 fold over the vehicle control. On the contrary, 0.1 microg/ml of prostaglandin E1 (PGE1) suppressed protein synthesis by 60%. Prostaglandin E2 (PGE2) also inhibited protein synthesis with an IC50 of 0.4 microg/ml. The stimulatory effects of thrombin (10 U/ml) can be inhibited by antithrombin III (2 U/ml) (a natural thrombin inhibitor) with heparin (2 U/ml), PPACK (D-Phe-Pro-ArgCH2Cl) (20-50 microg/ml) (a serine protease inhibitor), and PGE2 (0.5-1.0 microg/ml). Moreover, TRAP (20-40 microg/ml), a thrombin receptor agonist peptide, also exerted a stimulatory effect (1.21-1.37 fold). In conclusion, thrombin-induced protein synthesis by pulp cells is dependent on proteolytic activity, but not on binding to receptors. Both PGE1 and PGE2 exert suppressive effects on protein synthesis, indicating that interactions between thrombin and prostaglandins are important in regulating the inflammation, repair and regeneration of pulp tissue following injury.

Cutaneous sinus tract caused by vertical root fracture

This report presents a rare case of odontogenic cutaneous sinus tract caused by a vertical root fracture. The root-fractured molar was probably caused by an accidental blow by a cow 3 years ago. Despite all treatments by physicians and surgeons for nearly 1 year, the sinus tract recurred repeatedly. After diagnosis and extraction of the fractured molar by the dentist, the sinus tract healed uneventfully in a month.

Ganglion cyst and synovial cyst of the temporomandibular joint. Two case reports

Ganglion cysts and synovial cysts are lesions rarely associated with the temporomandibular joint. Ganglion cysts arise from myxoid degeneration of the connective tissue of the joint capsule, are filled with viscoid fluid or gelatinous material, and have a fibrous lining. Synovial cysts also contain gelatinous fluid and are lined with cuboidal to somewhat flattened cells consistent with a synovial origin. One case of a ganglion cyst and one case of a synovial cyst of the temporomandibular joint are presented, and their differential diagnosis and management are discussed.

Recombinant human monoclonal antibody IgG1b12 neutralizes diverse human immunodeficiency virus type 1 primary isolates

The CD4-binding domain of human immunodeficiency virus type 1 (HIV-1) gp120 elicits antibodies that are present in infected human sera. Monoclonal antibodies that recognize the HIV-1 gp120 CD4-binding domain have been isolated. Some of these antibodies can neutralize laboratory-adapted strains of HIV-1 and probably mediate neutralization by interfering with virus binding to its cellular CD4 receptor. However, most anti-CD4 binding domain antibodies do not neutralize primary HIV-1 isolates. We used primary HIV-1 isolates in an infectivity reduction assay to test the uniquely derived anti-CD4 binding domain recombinant human monoclonal antibody, IgG1b12. All of the tested HIV-1 isolates were neutralized by this antibody. Additional studies indicated that neutralization of a primary isolate with MAb IgG1b12 did not require continuous exposure of human peripheral blood mononuclear cell cultures to the antibody. Finally, a complete IgG1 molecule of an in vitro-selected b12 FAb mutant with a > 400-fold increase in affinity was assembled, expressed in mammalian cells, and evaluated in the infectivity reduction assay in comparative studies with the parent IgG1b12 antibody. The mutant did not retain the level of primary isolate neutralization potency that was a property of the parent molecule. Thus, we confirm that recombinant IgG1b12 has a unique specificity, and that it can neutralize all primary isolates tested in human PBMC cultures in vitro.

Intentional replantation of a mandibular molar with calcified canal: a case report

Intentional replantation is an accepted endodontic technique for treating teeth in which both conventional and/or surgical endodontic treatments are not recommended. A rare case using intentional replantation technique on one mandibular molar has been successfully treated. This procedure was used owing to inaccessible calcified canal and pain intolerance of the patient. A thirty month post-operative evaluation revealed an asymptomatic, functional tooth with no radiographic signs of pathosis. The favorable results obtained in this case might be attributed to certain factors, such as occlusal adjustment prior to replantation, maintaining asepsis during replantation, no-damaging pressure during extraction, use of noneugenol periodontal packing, preservation of the vitality of the periodontal ligament, a minimal extraoral period, non-rigid splinting, apicoectomy and retrograde amalgam filling were done for hermetic apical seal. Intentional replantation may be limited to those cases when conventional endodontic therapy is not possible, but may be a treatment alternative to maintain the dentition and save an otherwise hopeless tooth.

Intentional replantation for iatrogenic perforation of the furcation: a case report

Intentional replantation is an accepted endodontic procedure for treatment of teeth in which conventional surgical endodontic treatment is contraindicated. This article presents a rare case of intentional replantation of a mandibular molar that had severe periodontal destruction resulting from iatrogenic perforation of the furcation. A 17-month follow-up evaluation revealed an asymptomatic and functional tooth with no radiographic signs of pathosis. The favorable results obtained might be attributed to the preservation of the vitality of the periodontal ligament; the absence of damaging pressure during extraction; the minimal extraoral treatment time; the use of nonrigid splinting; and the immediate repair of the perforation during a one-visit endodontic procedure. The results obtained with this tooth may indicate the possibility of a successful surgical technique for this otherwise hopeless complication of endodontic therapy.

Implant-retained mandibular overdentures: a simplified effective treatment option

The use of implant-retained mandibular overdentures is a treatment option for compromised patients. The combination of using a bar and intracoronal attachments to connect two implants provides cross-arch stabilization, good retention and stability for the overdenture which is still mainly supported by soft tissue. However, connecting the component parts of an internal attachment to the removable overdenture requires numerous laboratory and clinical procedures and the resulting errors can prevent proper seating of the prosthesis. A simple, direct technique, totally controlled by the operator, is presented to increase the precision of the assemble of the component parts and contribute to the precise fit if the implant-retained overdenture. The advantages, disadvantages and the rational treatment are discussed.

Gingival mass as the primary manifestation of multiple myeloma: report of two cases

Two cases of multiple myeloma with primary manifestations in the oral cavity are reported, both presenting as a mandibular gingival/alveolar mass with hypermobility of the adjacent teeth. Roentgenographic examination demonstrated concomitant "punched-out" osteolytic jawbone lesions. After biopsy of the gingival mass was performed, multiple myeloma was subsequently diagnosed in both cases. Systemic bone scanning revealed multiple osteolytic bone lesions involving the skull and various skeletal bones. Hematologic screening showed a monoclonal gammopathy in both cases. A bone marrow biopsy confirmed the diagnosis of multiple myeloma. Awareness of the maxillofacial manifestations of multiple myeloma is important for early detection of the disease, especially in patients with initial oral involvement.

Induction of superoxide dismutase isozymes by tumor necrosis factor-alpha and lipopolysaccharide in cultured normal and hyperplastic gingival fibroblasts

To determine whether lipopolysaccharide (LPS) and tumor necrosis factor-alpha (TNF-alpha) are involved in the induction of superoxide dismutase (SOD) in gingival tissue, we examined their effect on induction of SOD isozymes in cultured normal (NGF) and phenytoin-induced hyperplastic (PHF) gingival fibroblasts. Treatment of both NGFs and PHFs with 10 to 50 ng/mL TNF-alpha for 24 hours increased the level of manganese SOD (MnSOD) to as much as four times the level of untreated cultures. PHFs, but not NGFs, were shown to be responsive to TNF-alpha in eliciting a significant increase in copper-zinc SOD (Cu/ZnSOD), albeit in a lesser amount than MnSOD. Additionally, treatment of both types of cells with 5 to 50 mg/mL of LPS for 24 hours also elicited an increase in the levels of MnSOD. Again, an LPS-induced increase in Cu/ZnSOD levels could only be demonstrated in PHFs, but not in NGFs. These observations were further confirmed by comparing the achromatic bands associated with SOD isozymes exhibited in the electrophoretogram using a nondenaturing polyacrylamide electrophoresis technique. These results indicate that TNF-alpha and LPS were capable of inducing both MnSOD and Cu/ZnSOD simultaneously in PHF fibroblasts. PHFs may be inherently more capable than NGFs in combating oxidative stress.

[Hereditary gingival fibromatosis: a case report]

Hereditary gingival fibromatosis is an uncommon congenital anomaly of undetermined etiology, the condition is manifested as a dense, diffuse, smooth or nodular overgrowth of the gingival tissue, usually begins with the eruption of the permanent incisors. However, it may happen as early as the eruption of the deciduous teeth. The case, a 30 years old woman with normal stature, visited our dental clinic because of "overgrown gum" which greatly affected mastication and appearance. A review of her past medical history revealed no relevant diseases. Oral examination showed gross fibrous enlargement of gingival without inflammation or swelling. Her father, two sisters and one daughter also suffered from this disease. Microscopically, there is a obvious increase in the amount of connective tissue that is relatively avascular and consists of densely arranged collagen bundles and numerous fibroblasts. The surface epithelium is thickened and acanthotic with elongated rete pegs. Gingivectomy with flap operation were performed to correct the gingival overgrowth. After periodontal treatment, two fixed partial dentures were constructed to replace the missing right upper and lower first molars. One year after operation, no obvious recurrence was noted clinically.

Primary extramedullary plasmacytoma in cyclosporine-induced gingival overgrowth. A case report

An unusual solitary extramedullary plasmacytoma developed in the gingiva of a 28 year-old male renal transplant patient with cyclosporine (CyA)-induced gingival overgrowth. On initial presentation, there was no suspicion of a tumor within the lesion. One year later, however, the lesion had increased progressively in size, and its surface was ulcerated. At this time, the lesion was excised by gingivectomy, and histopathological examination revealed plasmacytoma. CyA was discontinued and the patient has been closely observed for 4 years with no recurrence of the gingival lesion.

Characterization of cloned human endothelin receptors

Two subtypes of human endothelin receptors, ETA and ETB, have been cloned and stably expressed in Chinese Hamster Ovary cells. These receptors have been characterized by [125I]-endothelin-1 binding and phosphatidyl inositol hydrolysis using the potent peptidyl ETA antagonists BQ-123 and BQ-153, as well as the potent ETB agonist, sarafotoxin S6c. In binding studies, Ki values for BQ-123 and BQ-153 are 17 nM and 13 nM for ETA compared to 11,100 nM and 7200 nM for ETB. Conversely, Ki values for sarafotoxin S6c are 2800 nM for ETA and 0.29 nM for ETB. Endothelin-1 stimulates phosphatidyl inositol hydrolysis in cells expressing either ETA or ETB with EC50 values of 0.2-0.3 nM, while sarafotoxin S6c stimulates phosphatidyl inositol hydrolysis only in ETB expressing cells with an EC50 value of 0.2 nM, consistent with the binding data. Comparison of binding data for the cloned and expressed human receptors with binding data for receptors obtained from human tissues indicates the cloned and expressed receptors are essentially indistinguishable from the naturally occurring receptors.

Localized periodontitis induced by rubber bands. Report of two cases

Two cases of severe localized periodontal destruction caused by rubber bands migrating toward the apices subgingivally are reported. In both cases the patients received periodontal treatment followed by orthodontic treatment and the affected teeth were maintained for two years without extraction. The inappropriate use of rubber bands may cause severe periodontal destruction or even lead to tooth mortality. The use of retentive hooks on orthodontic bands and twisted wire ligatures, as well as close professional supervision, are highly recommended to avoid this hazardous situation.

Cloning, characterization and developmental regulation of two members of a novel human gene family of neurite outgrowth-promoting proteins

This report describes the cloning, expression and characterization of two members of a novel human gene family of proteins, HBNF and MK, which exhibit neurite outgrowth-promoting activity. The HBNF cDNA gene codes for a 168-residue protein which is a precursor for a previously described brain-derived heparin-binding protein of 136 amino acids. The second human gene identified in this study, called MK, codes for a 143-residue protein (including a 22-amino acid signal sequence) which is 46% homologous with HBNF. Complementary DNA constructs coding for the mature HBNF and MK proteins were expressed in bacteria and purified by heparin affinity chromatography. These recombinant proteins exhibited neurite-outgrowth promoting activity, but lacked mitogenic activity. The HBNF gene is expressed in the brain of adult mice and rats, but only minimal expression of MK was observed in this tissue. Different patterns of developmental expression were observed in the embryonic mouse, with MK expression peaking in the brain between days E12 and E14 and diminishing to minimal levels in the adult, while expression of HBNF mRNA was observed to gradually increase during embryogenesis, reaching a maximal level at birth and maintaining this level into adulthood. Expression of these genes was also observed in the human embryonal carcinoma cell line, NT2/D1. Retinoic acid induced the expression of HBNF and MK 6- and 11-fold, respectively, in this cell line. Our studies indicate that HBNF and MK are members of a new family of highly conserved, developmentally regulated genes that may play a role in nervous tissue development and/or maintenance.

Identification of multiple epidermal growth factor-stimulated protein serine/threonine kinases from Swiss 3T3 cells

Growth factor activation of serine/threonine protein kinases was studied by treating quiescent Swiss 3T3 cells with epidermal growth factor (EGF) and examining cytosolic extracts for protein kinase activity under conditions inhibitory to calcium- and cyclic nucleotide-dependent kinases. Cytosolic extracts of cells stimulated for 5 min were fractionated by Mono Q fast protein liquid chromatography. Eight peaks of kinase activity were resolved, of which five were stimulated by EGF treatment of cells. These peaks were revealed using the synthetic peptide Arg-Arg-Leu-Ser-Ser-Leu-Arg-Ala (S6 peptide), 40 S ribosomal S6 protein, glycogen synthase, microtubule-associated protein 2, and myelin basic protein as substrates. The peaks varied in the kinetics of their activation by EGF and in their response to insulin. Selected peaks were resolved further by sizing gel chromatography. The results together indicate that at least seven distinct fractions of cytosolic kinase activities are stimulated in Swiss 3T3 cells by EGF. One of these, which phosphorylates both S6 protein and S6 peptide, is similar to the S6 kinase characterized previously in this cell line by others. Four additional activities that also phosphorylate the S6 protein and S6 peptide appear unrelated to this enzyme. Finally, two kinase activities that phosphorylate both myelin basic protein and microtubule associated protein 2 are EGF stimulated. One is similar to an insulin-stimulated microtubule-associated protein 2 kinase described in other cell lines whereas the other seems to represent a novel activity. Several of these EGF-stimulated activities were inactivated by protein phosphatases, suggesting that they might be regulated by phosphorylation.

Stimulation of protein phosphatase activity by insulin and growth factors in 3T3 cells

Incubation of Swiss mouse 3T3-D1 cells with physiological concentrations of insulin resulted in a rapid and transient activation of protein phosphatase activity as measured by using [32P]phosphorylase a as substrate. Activation reached a maximum level (140% of control value) within 5 min of addition and returned to control levels within 20 min. The effect of insulin was dose-dependent with half-maximal activation occurring at approximately 5 nM insulin. This activity could be completely inhibited by addition of the heat-stable protein inhibitor 2, which suggests the presence of an activated type-1 phosphatase. Similar effects on phosphatase activity were seen when epidermal growth factor and platelet-derived growth factor were tested. These results suggest that some of the intracellular effects caused by insulin and growth factors are mediated through the activation of a protein phosphatase.

Regulation of glycogen synthase activity by growth factors. Relationship between synthase activation and receptor occupancy

Platelet-derived growth factor (PDGF) was found to stimulate the activity of glycogen synthase, an enzyme subjected to regulation by phosphorylation-dephosphorylation reactions. In Swiss mouse 3T3 cells, the time course of enzyme activation by PDGF is very similar to that of epidermal growth factor (EGF) and insulin. A 3-fold maximal stimulation was observed by 30 min, and the enzyme activity ratio returned to basal levels by 100 min. The PDGF effect was maximal at 1 ng/ml (30 pM) and half-maximal stimulation was observed at 0.2 ng/ml (6 pM). Parallel measurements of 125I-PDGF binding indicate that binding was maximal by 10 min and thus should not be rate-limiting for enzyme activation. In addition, presaturation of the receptors with PDGF at 4 degrees C did not expedite subsequent enzyme activation at 37 degrees C. Removal of PDGF in the media after the 4 degrees C pretreatment did not affect the enzyme activation response, indicating that the continued presence of PDGF in the medium is not necessary after receptor binding is saturated. Results of sequential addition of PDGF, EGF, and insulin indicated a refractory period in the response system. This property is evident even when the second addition involved a different growth factor and is independent of the sequence of addition of the factors. There was little additivity in the actions of the three growth factors in effecting enzyme activation and suggests a common intermediate element in the three signalling pathways.

Characterization of the phosphotyrosyl protein phosphatase activity of calmodulin-dependent protein phosphatase

Calmodulin-dependent protein phosphatase from bovine brain and heart was assayed for phosphotyrosine and phosphoserine phosphatase activity using several substrates: 1) smooth muscle myosin light chain (LC20) phosphorylated on tyrosine or serine residues, 2) angiotensin I phosphorylated on tyrosine, and 3) synthetic phosphotyrosine- or phosphoserine-containing peptides with amino acid sequences patterned after the autophosphorylation site in Type II regulatory subunit of the cAMP-dependent protein kinase. The phosphatase was activated by Ni2+ and Mn2+, and stimulated further by calmodulin. In the presence of Ni2+ and calmodulin, it exhibited similar kinetic constants for the dephosphorylation of phosphotyrosyl LC20 (Km = 0.9 microM, and Vmax = 350 nmol/min/mg) and phosphoseryl LC20 (Km = 2.6 microM, Vmax = 690 nmol/min/mg). Dephosphorylation of phosphotyrosyl LC20 was inhibited by phosphoseryl LC20 with an apparent Ki of 2 microM. Compared to the reactions with phosphotyrosyl LC20 as the substrate, reactions with phosphotyrosine-containing oligopeptides exhibited slightly higher Km and lower Vmax values. The reaction with the phosphoseryl peptide based on the Type II regulatory subunit sequence exhibited a slightly higher Km (23 microM), but a much higher Vmax (4400 nmol/min/mg) than that with its phosphotyrosine-containing counterpart. Micromolar concentrations of Zn2+ inhibited the phosphatase activity; vanadate was less potent, and 25 mM NaF was ineffective. The study provides quantitative data to serve as a basis for comparing the ability of the calmodulin-dependent protein phosphatase to act on phosphotyrosine- and phosphoserine-containing substrates.

Protein turnover in insulin-treated, alloxan-diabetic lean and obese Zucker rats

Obese and lean Zucker rats were made diabetic by intracardiac injections of alloxan (65-72 mg/kg body weight) and then given daily injections of protamine zinc insulin [1.25 U/(100 g/d)] for 6, 9 and 12 d. Body weight, food intake, plasma glucose and immunoreactive insulin concentrations were not different for lean and obese diabetic rats of similar ages. Rates of increase in carcass protein, mixed muscle protein and myofibrillar protein were less in obese than in lean rats. However, rates of increase for the sarcoplasmic fraction were not different. Fractional rates of synthesis of total muscle protein and myofibrillar protein, as determined by continuous intravenous infusion of [14C]tyrosine, were comparable in the two genotypes. Fractional rate of myofibrillar protein degradation, as determined by urinary 3-methylhistidine excretion, was higher in obese than in lean rats. Differences in calculated absolute rates between genotypes did not parallel differences in the fractional rates, due mainly to a smaller protein mass in obese rats. As a consequence, absolute synthetic rates were lower in obese rats, while absolute degradation rates were similar in the two genotypes. In contrast, rates of liver protein synthesis were similar in obese and lean rats, whether expressed as fractional or absolute rates. These results indicate that decreased protein deposition in the obese animal is a consequence of both an absolute decrease in protein synthesis in muscle as well as a disproportionately elevated protein degradation in muscle. Hyperinsulinemia normally seen in obese rats may be an adaptive response to minimize the impaired balance between protein synthesis and degradation.

Epidermal growth factor stimulates glycogen synthase activity in cultured cells

Addition of epidermal growth factor (EGF) to quiescent cultured cells was found to stimulate the activity of glycogen synthase (UDPglucose:glycogen 4-alpha-D-glucosyltransferase, EC 2.4.1.11), an enzyme subjected to regulation by covalent modification. In Swiss mouse 3T3 cells, the activation by EGF paralleled the effect seen with insulin; the time course and dose-response curves of the two polypeptide factors were similar. Stimulation of enzyme activity ratio [(activity in the absence of glucose 6-phosphate)/(activity in the presence of glucose 6-phosphate)] was maximal after 20-30 min of incubation. Both factors caused a maximal stimulation of 2.5-fold in synthase activity ratio at approximately equal to 10 nM, and the half-maximal effect was observed at 0.1-1 nM. Insulin and EGF exhibited partial additivity in effecting this enzyme activation. In contrast, human A431 cells showed no response to insulin. Although quantitatively different, the EGF effect in the latter cells was time dependent, reaching a maximum at 90 min, and dose dependent, with a maximal stimulation of 4-fold in synthase activity ratio at 10 nM. Half-maximal effect was observed at 0.3 nM EGF. Direct quantitation of allosteric effectors (glucose 6-phosphate, adenine nucleotides, and Pi) present in the enzyme assay mixtures indicated that the observed activation was not simply a consequence of changes in metabolite concentrations. These results suggest that EGF may be important in regulating glycogen synthesis through phosphorylation/dephosphorylation mechanisms.

Adipose lipoprotein lipase in insulin-treated diabetic lean and obese Zucker rats

Obese and lean alloxan-diabetic rats were given daily injections of insulin for 9 days. Plasma glucose and insulin concentrations were not different between the two genotypes given comparable amounts of insulin. Carcass fat and epididymal and retroperitoneal fat pad weights increased as the dose of insulin was increased. At each of four doses, fatties had larger fat cells, bigger pads, and more body fat than lean rats. Adipose lipoprotein lipase (LPL) activity per pad or per fat cell was increased by insulin. Except for the lowest dose of insulin, LPL activity was higher in obese rats than in lean rats. LPL activity per cell and cell size were highly correlated. However, when differences in cell size were corrected for, no significant effect of genotype existed. Cardiac LPL activities were different between the two genotypes only in nondiabetic rats. These results suggested that both insulin and some other genetic factors were important in elevating adipose LPL activities and thus fat deposition in obese Zucker rats.

Effect of insulin on fat and protein deposition in diabetic lean and obese rats

Five-week-old male obese and lean Zucker rats were made comparably diabetic by intracardiac injections of alloxan (65-72 mg/kg body wt). Lean rats were then given daily injections of protamine zinc insulin at 3 doses: 0.25, 1.25, and 4.0 U.100 g body wt-1.day-1 for 3 wk. Obese rats received identical amounts as corresponding lean controls independent of body weights. The drop of blood glucose concentration after injections of regular insulin and the percentage fall in radioactive plasma insulin after injections of 125I-insulin were comparable in lean and obese rats. Weight gain, fat gain, and protein gain over 21 days increased with increasing amounts of insulin administered. However, at the same dose of insulin, although weight gain was comparable, fat gain was higher and protein gain was lower in obese rats when compared to lean controls. These results suggest that the enhanced lipid deposition of the obese Zucker rat is not totally dependent on insulin levels, but is exaggerated by hyperinsulinemia.