Effect of immersion in sodium hypochlorite on torque and fatigue resistance of nickel-titanium instruments.

This study investigated the effect of immersion in sodium hypochlorite (NaOCl) on torque and fatigue resistance of two nickel-titanium files. Size 25 .04 ProFile and RaCe files were immersed in 5.25% NaOCl for 1 or 2 hours at temperatures of 21 degrees C and 60 degrees C. Torque and angle at failure were measured according to ISO 3630-1. Resistance to cyclic fatigue was determined by counting rotations to breakage in a 90 degrees curve with a 5-mm radius. Data were analyzed by 2-way analysis of variance. Torsional resistance of both rotaries was not significantly affected by immersion in NaOCl, except after 2 hours of immersion at 60 degrees C. Resistance to cyclic fatigue decreased significantly for ProFile and RaCe instruments after immersion in NaOCl. Spontaneous fractures occurred in 28 of 160 files during immersion in NaOCl. In conclusion, nickel-titanium rotaries have reduced resistance to cyclic fatigue after contact with heated NaOCl and may then be considered single-use instruments.

The Basal phosphorylation sites of endothelial nitric oxide synthase at serine (Ser)1177, Ser116, and threonine (Thr)495 in rat molar epithelial rests of Malassez.

BACKGROUND: The epithelial rests of Malassez (ERM) are derived from the Hertwig's epithelial root sheath during tooth development. The ERM contain endothelial nitric oxide synthase (eNOS), but the existence of phosphorylation site/s of eNOS in the ERM is unclear. METHODS: Rat molars with periodontium were perfusion- and post-fixed, decalcified, and frozen-sectioned. Free-floating sections were incubated using antisera against total eNOS, eNOS phosphorylated at serine (Ser)1177, Ser116, and threonine (Thr)495. The signal intensities of t-eNOS, p-eNOS at Ser1177 and Ser116 in the ERM were measured by densitometry and statistically analyzed. RESULTS: In the ERM, localization of total eNOS and the phosphorylation sites of eNOS at Ser1177 and Ser116 were detected, while a basal localization of eNOS phosphorylated at Thr495 in the ERM was undetectable. For p-eNOS at Ser116 regional differences in phosphorylation were detected. CONCLUSIONS: The basal production of NO by eNOS in the ERM is modulated by phosphorylation of eNOS at Ser1177 and Ser116 residues, while the basal activity of the eNOS is not influenced by phosphorylation of eNOS at Thr495 residue. This provides evidence that phosphorylation plays a key role for regulation of the catalytic activity of eNOS.

Endothelial nitric oxide synthase phosphorylated at Ser116 is localized in nerve fibers of the rat glandulae palatinae.

It is known that total endothelial nitric oxide synthase (eNOS) is localized in peripheral nerve fibers, but the existence of the phosphorylation site/s of eNOS in peripheral nerve fibers is unknown. In the perfusion-fixed and decalcified sections of rat palates, eNOS and eNOS phosphorylated at Ser(116) were identified in the nerve fibers of the glandulae palatinae. The localization of eNOS phosphorylated at Ser(1177) and Thr(495) in nerve fibers was undetectable. It is concluded that eNOS is phosphorylated at Ser(116) in nerve fibers of the glandulae palatinae under basal conditions. The basal Ser(1177) and Thr(495) phosphorylation of eNOS are missing in nerve fibers of the glandulae palatinae.

Localization of the NO-cGMP signaling pathway molecules, NOS III-phosphorylation sites, ERK1/2, and Akt/PKB in osteoclasts.

BACKGROUND: Nitric oxide (NO) mediates different cellular functions by activating soluble guanylate cyclase (sGC) that converts guanosine-5'-triphosphate (GTP) to cyclic guanosine-3',5'-monophosphate (cGMP). Membrane-bound GCs produce cGMP in response to natriuretic peptides in osteoblasts, but neither the NO-target enzyme sGC, nor the phosphorylation sites of NOS III, nor their regulation by extracellular signal-regulated kinases 1 and 2 (ERK1/2) and Akt/protein kinase B (Akt/PKB) in osteoclasts have been established. METHODS: Rat molars with periodontium were perfusion- and post-fixed, decalcified, and frozen-sectioned. Free-floating sections were stained using nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) and tartrate-resistant acid phosphatase (TRAP) histochemical techniques and immunoreacted with antisera against NO-synthase (NOS) I-III, NOS III phoshorylated at Thr495, NOS III phoshorylated at Serine1177 (Ser1177), ERK1/2, phosphorylated ERK1/2, Akt/PKB, phosphorylated Akt/PKB, sGC (alpha2/beta1), and cGMP. RESULTS: NADPH-d staining and immunostaining of NOS I-III, NOS III phosphorylated at Ser1177, ERK1/2, Akt/PKB, phosphorylated Akt/PKB, sGC (alpha2 and beta1-subunits), and cGMP were detected in osteoclasts. Immunohistochemical reaction products for NOS III phosphorylated at threonine495 (Thr495) and phosphorylated ERK1/2 could not be identified in osteoclasts. Comparison of TRAP activity and immunostaining for sGC beta1-subunit revealed that sGC beta1-subunit is only expressed in a sub-population of osteoclasts. CONCLUSIONS: NO is likely to be generated by NOS I and NOS III in osteoclasts. The inconstant expression of NOS II in some osteoclasts may be explained with inducible expression of NOS II upon physiological cell activation. Localization of the sGC alpha2- and beta1-subunits and cGMP in osteoclasts is compatible with an involvement of NO-sGC signaling in the homeostasis of osteoclasts. The phosphorylation site of NOS III at Ser1177 and phosphorylated Akt/PKB are involved in regulation of NO production by NOS III in osteoclasts under basal conditions.

Diagnosis of malignant ascites in prostate cancer by measurement of prostate specific antigen.

We were confronted with a case of ascites in a man with known cirrhosis and advanced prostate cancer. Initial studies of ascitic fluid suggested cirrhosis as the cause of ascites. However, a prostate-specific antigen (PSA) study of ascitic fluid strongly suggested that the ascites was caused by prostate cancer. Subsequent cytologic studies confirmed malignant ascites. We suggest that measurement of PSA may be a valuable adjunctive study for the diagnosis of malignant effusions in prostate cancer.

Solid-state nuclear magnetic resonance microscopy demonstrating human dental anatomy.

OBJECTIVE: Magnetic resonance imaging has become a common diagnostic tool in medical practice. It is a common view that solid-state material lacking a sufficient amount of unpaired nuclear spins, in particular proton spins, is impossible to depict with clinically used magnetic resonance devices. Characteristically rapid dephasing, caused by relatively short spin-spin relaxation (T(2) time) also leads to broad resonance lines. A newly introduced technique, constant-time imaging, uses 3 phase-encoding gradients for the acquisition of only one complex data point per phase-encoding step, resulting in detection times of only a few microseconds and extremely sharp resonance lines. STUDY DESIGN: Using a Bruker spectrometer AMX 300 WB (300 MHz, 7.1 T) with a microimaging attachment, we performed solid-state magnetic resonance imaging of whole teeth. Data processing was carried out by means of 3-dimensional Fourier analysis, and reconstructions were performed by the ParaVision (Bruker) software system. RESULTS: Dental hard tissues (enamel, dentin, and root cementum) and pulpal soft tissue could be depicted in 2-dimensional and 3-dimensional images. The voxel resolution isotropically reached 195 microm. CONCLUSION: The constant-time imaging technique enabled a naturalistic and nondestructive visualization of the teeth without application of ionizing radiation. This technique bears the potential to help us overcome the limitations of clinically used standard magnetic resonance tomography devices and offers new perspectives for dental imaging.

Nickel-titanium: options and challenges.

The introduction of nickel-titanium (NiTi) as material for endodontic instruments about 15 years ago opened many new perspectives. Many dentists and scientists see a benefit in using NiFi files. Initial problems such as frequent fractures and the uncertainty of the best way to use them have been solved. Other challenges such as enhancing the cutting ability or optimizing the speed, torque, and fatigue are currently being addressed. Some clinicians are skeptical because they see this approach as too mechanical. Nevertheless, the combination of anatomic, biologic, and pathophysiologic knowledge with the use of NiTi instruments is a large step forward in optimizing the quality of root canal treatment worldwide.

ProTaper NT system.

This article reviews the design and clinical use of the ProTaper NT file system.

A lateral flow-based ultra-sensitive p24 HIV assay utilizing fluorescent microparticles.

The current demand for HIV diagnostic tests in resource-limited settings is not being fully addressed by the currently available nucleic acid test or enzyme-linked immunosorbent assay-based p24 antigen assays. This is primarily due to their high cost, their requirement for controlled laboratory conditions and/or personnel, or the relatively long turn-around time for test results. Self performing lateral flow assays address all of these issues but to date have not reached the level of analytical sensitivity for HIV p24 demonstrated by current generation enzyme-linked immunosorbent assay technology. This report presents an initial prototype lateral flow assay for HIV p24 antigen capable of achieving subpicogram per milliliter limits of analytical sensitivity and requiring less than 40 minutes to yield results.

Efficacy of prophylactic warfarin for prevention of thalidomide-related deep venous thrombosis.

BACKGROUND: Deep venous thrombosis (DVT) is a common complication of thalidomide treatment. There is little information to guide clinicians in selecting effective preventive treatments and physician practice varies. We sought to determine whether prophylactic anticoagulation with warfarin prevents DVT related to thalidomide treatment. METHODS: We reviewed the records of 131 patients receiving thalidomide for a variety of indications. Fifty-five patients were prescribed warfarin with the intent of preventing DVT. Thirty-seven patients received warfarin at a dose of 1-2 mg per day (low dose) and 18 received a dose intended to raise the INR to 2-3 (high dose). RESULTS: Twenty-one of the 131 patients developed venous thrombosis during thalidomide treatment. Eighteen of the 76 patients (23.7%) who were not prescribed prophylactic anticoagulation developed DVT compared to 3 of the 55 patients (5.5%) who were prescribed any dose of prophylactic warfarin (P = 0.010). Only 1 of the 37 patients who received low-dose warfarin developed DVT (P = 0.011). Bleeding complications occurred in 4 patients, all of whom were receiving high-dose warfarin. CONCLUSION: Prophylactic anticoagulation with warfarin reduces the risk of thrombosis during thalidomide treatment. Low-dose warfarin may be as effective as higher dose treatment and may result in fewer bleeding complications.

Alcohol abuse predicts progression of disease and death in patients with lung cancer.

BACKGROUND: Few studies have examined long-term outcomes in alcohol-abusing patients with lung cancer. The purpose of this study was to examine the effect of alcohol abuse on the prognosis of patients with lung cancer. METHODS: The study was composed of 114 consecutive patients with nonsmall-cell lung cancer treated at a Department of Veterans Affairs Medical Center. An alcohol-abusing group consisted of 36 patients with one of the following at the time of lung cancer diagnosis: positive screening questionnaire, alcohol consumption more than 5 drinks or cans of beer a day, or criteria for a diagnosis of alcohol dependence/abuse according to the Diagnostic and Statistical Manual for Mental Disorders IV. The comparison group consisted of 78 nonabusing patients. RESULTS: Alcohol abusers, compared with nonabusers, had worse Kaplan-Meier overall survival (median 8.5 versus 17.5 months, p = 0.05) and progression-free survival (median 6.0 versus 15.5 months, p = 0.04). In multivariate analyses including alcohol abuse, Charlson comorbidity, pack-years smoking, performance status, and stage, only stage of disease, performance status, and alcohol abuse (odds ratio = 3.44, 95% confidence interval = 1.17 to 10.1, p = 0.02) predicted progression of disease or death within 12 months of diagnosis. Alcohol abuse was also an independent predictor of disease-specific survival (hazard ratio = 1.65, 95% confidence interval = 1.01 to 2.80, p = 0.05) and progression-free survival (hazard ratio = 1.79, 95% confidence interval = 1.12 to 2.86, p = 0.01) among patients with lung cancer. CONCLUSIONS: Alcohol-abusing patients with nonsmall-cell lung cancer have worse outcomes than nonabusing patients. The adverse prognosis associated with alcohol abuse is independent of comorbidity, performance status, or smoking history.

Localization of the neuropeptide galanin in nerve fibers and epithelial keratinocytes of the rat molar gingiva.

Knowledge of the histochemical substrates of cellular and neurovascular connections in the gingiva is essential in order to understand the initial mechanisms of inflammation in the periodontium. Since the localization of the neuroendocrine peptide galanin in the gingiva is still unclear, we used immunohistochemical, in situ hybridization and immunoblot techniques to assess the localization of galanin in the gingiva of rat molars. Galanin-immunoreactive nerve fibers were located around blood vessels in the lamina propria, beneath the epithelium, in the epithelial-proprial junction and in the basal layer of the epithelium. Galanin was highly expressed in the suprabasal keratinocytes of the gingival epithelium. The localization of galanin in gingival nerve fibers and the expression of galanin in keratinocytes of the gingival epithelium indicate that galanin may be a possible regulator of different cellular functions in the gingiva.

Granulocyte-macrophage colony-stimulating factor is a chemoattractant cytokine for human neutrophils: involvement of the ribosomal p70 S6 kinase signaling pathway.

GM-CSF stimulates proliferation of myeloid precursors in bone marrow and primes mature leukocytes for enhanced functionality. We demonstrate that GM-CSF is a powerful chemotactic and chemokinetic agent for human neutrophils. GM-CSF-induced chemotaxis is time dependent and is specifically neutralized with Abs directed to either the ligand itself or its receptor. Maximal chemotactic response was achieved at approximately 7 nM GM-CSF, and the EC(50) was approximately 0.9 nM. Both concentrations are similar to the effective concentrations of IL-8 and less than the effective concentrations of other neutrophil chemoattractants such as neutrophil-activating peptide-78, granulocyte chemotactic protein-2, leukotriene B(4), and FMLP. GM-CSF also acts as a chemoattractant for native cells bearing the GM-CSF receptor, such as monocytes, as well as for GM-CSF receptor-bearing myeloid cell lines, HL60 (promyelomonocyte leukemic cell line) and MPD (myeloproliferative disorder cell line), following differentiation induction. GM-CSF induced a rapid, transient increase in F-actin polymerization and the formation of focal contact rings in neutrophils, which are prerequisites for cell migration. The mechanism of GM-CSF-induced chemotaxis appears to involve the cell signaling molecule, ribosomal p70 S6 kinase (p70S6K). Both p70S6K enzymatic activity and T(421)/S(424) and T(389) phosphorylation are markedly increased with GM-CSF. In addition, the p70S6K inhibitor hamartin transduced into cells as active protein, interfered with GM-CSF-dependent migration, and attenuated p70S6K phosphorylation. These data indicate that GM-CSF exhibits chemotactic functionality and suggest new avenues for the investigation of the molecular basis of chemotaxis as it relates to inflammation and tissue injury.

NO-cGMP signaling molecules in the rat epithelial rests of Malassez.

The epithelial rests of Malassez (ERM) are derived from the disintegrating epithelial root sheath of Hertwig that guides root formation during tooth development. Low concentrations of nitric oxide (NO) produced by NO-synthase I (NOS I) and NOS III activate intracellular soluble guanylate cyclase (sGC) to produce intracellular cyclic guanosine 3':5'-monophosphate (cGMP), which triggers rapid cellular responses such as cell proliferation, cell differentiation, and apoptosis under physiological conditions. The presence of NOS I-III, sGC (alpha2- and beta1-subunits) and cGMP in the ERM was investigated by immunohistochemistry. Rat molars with periodontium were perfusion and postfixed, decalcified, frozen-sectioned, and sections were immunostained. NOS I, NOS III, sGC (alpha2- and beta1-subunits) and cGMP were localized with different densities in the ERM. The presence of NOS II in the ERM varied. The localization of NOS I, NOS III, sGC and cGMP in the ERM indicates an involvement of NO and/or NO-cGMP signal pathway molecules in homeostasis of a variety of physiological processes in the ERM. These could include regulation of cell proliferation, cell differentiation and apoptosis.

Sweet's syndrome associated with sargramostim (granulocyte-macrophage colony stimulating factor) treatment.

Sweet's syndrome is an acute febrile neutrophilic dermatosis that is a known complication of the administration of filgrastim, a drug that causes increased neutrophil proliferation and differentiation. This complication has not previously been reported during treatment with sargramostim, a hematopoietic cytokine with activity that overlaps filgrastim. We report a case of Sweet's syndrome in association with sargramostim treatment following chemotherapy for acute myelogenous leukemia. A suspected second episode occurred after subsequent chemotherapy and sargramostim treatment. Physicians should be aware of this possible association because the signs and symptoms of Sweet's syndrome are easily mistaken as being due to infection.