Modulation of the Initial Mineralization Process of SaOS-2 Cells by Carbonic Anhydrase Activators and Polyphosphate

Ca-phosphate/hydroxyapatite (HA) crystals constitute the mineral matrix of vertebrate bones, while Ca-carbonate is the predominant mineral of many invertebrates, like mollusks. Recent results suggest that CaCO₃ is also synthesized during early bone formation. We demonstrate that carbonic anhydrase-driven CaCO₃ formation in vitro is activated by organic extracts from the demosponge Suberites domuncula as well as by quinolinic acid, one component isolated from these extracts. Further results revealed that the stimulatory effect of bicarbonate (HCO₃ ^?) ions on mineralization of osteoblast-like SaOS-2 cells is strongly enhanced if the cells are exposed to inorganic polyphosphate (polyP), a linear polymer of phosphate linked by energy-rich phosphodiester bonds. The effect of polyP, administered as polyP (Ca²⁺ salt), on HA formation was found to be amplified by addition of the carbonic anhydrase-activating sponge extract or quinolinic acid. Our results support the assumption that CaCO₃ deposits, acting as bio-seeds for Ca-carbonated phosphate formation, are formed as an intermediate during HA mineralization and that the carbonic anhydrase-mediated formation of those deposits is under a positive–negative feedback control by bone alkaline phosphatase-dependent polyP metabolism, offering new targets for therapy of bone diseases/defects.     

Qualitative quality control during urodynamic studies with TSPs for cystometry in men with lower urinary tract symptoms suggestive of benign prostatic hyperplasia

The aim of this study was to describe typical signal patterns (TSPs) by amplitude and pressure gradients and indicate the role and significance of them in quality control. A total of 582 measurements from a multicenter urodynamic study on males (mean age, 65.3 years) were re-analyzed. Using manual graphical analysis, we identified signal patterns by typical amplitude (A) and typical pressure gradient (PG). TSPs were classified into four types: I: fine structure (A < 3 cm H₂O); II: minor dynamic changes (A < 5 cm H₂O); III: major changes due to cough tests (A > 50 cm H₂O, PG > 100 cm H₂O/s); IV: typical major changes due to muscular activity: detrusor overactivity (A > 3 cm H₂O, PG > 1–5 cm H₂O/s), rectal contractions (A = 5–10 cm H₂O, PG = 5–10 cm H₂O/s), and straining (A > 5 cm H₂O, PG ≥ 30 cm H₂O/s). At beginning of and during filling, 91.8 and 98.3 % of traces showed the identical fine structure and minor changes between P _ves and P _abd tracings, and P _det tracing was quiet. 92.3 % of P _ves and P _abd traces had equal pressure changes at test coughs. During filling, 8.3 % traces showed straining, 17.4 % showed rectal contractions, and 33.7 % showed detrusor overactivity. Before voiding, 94 % of P _ves and P _abd traces had equal cough response. During voiding, 91.2 % of traces showed the same fine structure, 53.3 % of traces showed straining, and 15.3 % showed relaxation of the pelvic floor. After voiding, 91.2 % of traces had the same fine structure, and 87.5 % had an equal cough response. TSPs are a powerful tool for qualitative plausibility and quality control and are an indispensable pre-condition for good urodynamic practice.     

Oxidative stress is responsible for genotoxicity of camphorquinone in primary human gingival fibroblasts

Objectives

The photoinitiator camphorquinone (CQ), used in dental restorative materials, was found to be cytotoxic in cell cultures. Previously, we have shown that CQ induces alkali labile sites and DNA strand breaks in human gingival fibroblasts (HGF) associated with an increase of intracellular reactive oxygen species (ROS). Therefore, the objective of our study was to evaluate if DNA damage in HGF cells is caused by the generation of ROS.

Material and methods

HGF cells were treated with different concentrations (0.5–2.5 mM) of CQ. The cell viability was assessed using propidium iodide (PI) assay. Oxidative DNA damage was evaluated by an enzyme-modified comet assay using human 8-hydroxyguanine DNA-glycosylase 1 (hOGG1), which converts oxidized 7,8-dihydro-8-oxoguanine (8-oxoguanine) into DNA strand breaks and functions as a marker for oxidative modified DNA.

Results

The results showed that CQ induced DNA damage in HGF cells without cytotoxic effects for the chosen treatment time. CQ treatment led to the generation of 8-oxoguanine in DNA, which can be shown by a significant increase in tail moment after CQ treatment by the enzyme-modified comet assay.

Conclusion

It may be concluded that DNA damage due to CQ is caused by oxidative stress in gingival fibroblasts.

Clinical relevance

A more detailed insight into genotoxic mechanisms in oral cells can be of great importance for a better understanding of the biocompatibility of CQ.     

Risk factors for median mononeuropathy of the wrist in postpoliomyelitis patients

There is evidence that chronic cane, crutch, and wheelchair users are at increased risk for developing pain and functional compromise of the wrist and hand. This investigation examined the prevalence and risk factors for median mononeuropathy at the wrist in the postpoliomyelitis population. The medical records of 148 consecutive patients with histories of poliomyelitis were reviewed. Forty-nine percent of this cohort had complaints of wrist pain. The prevalence rate of carpal tunnel syndrome was 22% (n = 33). Age, sex, duration of disability, and work history did not significantly influence the relative risk of developing this disorder. However, the relative risk of developing this compression neuropathy at the wrist by using the combination of a cane and/or a crutch and a wheelchair was 4.86 (95% confidence interval 2.35-10.06). The high risk associated with chronic cane, crutch, and wheelchair use shows the need for developing preventive strategies.     

Acute ventilatory restriction in children after weaning off inhaled nitric oxide: relation to rebound pulmonary hypertension

Objective: To assess the interaction between pulmonary hemodynamics and respiratory mechanics during acute pulmonary hypertension. Patients: Ventilated and paralysed children treated with inhaled nitric oxide because of post-operative pulmonary hypertension. Interventions: Weaning of inhaled nitric oxide. Measurements: Air flow and airway pressure, calculation of dynamic respiratory system compliance and respiratory system resistance for each breath by multiple linear regression. Results: In four patients, increases in pulmonary arterial pressure from 26.1 to 56.7 mmg (p < 0.001) during weaning off nitric oxide were associated with decreases in tidal volume (from 9.7 → 8.2 ml/kg, p < 0.01) and reductions in dynamic respiratory system compliance (from 0.52 → 0.34 cmH₂0/ml/kg, p < 0.001), while respiratory system resistance was unchanged. Conclusions: Impaired ventilation during acute pulmonary hypertension is predominantly related to a reduction in respiratory system compliance. Received: 26 March 1998 Final revision received: 9 June 1998 Accepted: 30 July 1998     

Evaluation of an end-tidal portable ETCO2 colorimetric breath indicator (COLIBRI)

Evaluation of tube position is important after in-hospital and prehospital emergency intubation. Colorimetric breath indicators are devices for immediate control of tube positioning by showing a color change according to end-tidal CO2 (ETCO2) concentrations. We hypothesized that colorimetric breath indicators can yield reliable results for confirmation of tube position. The aim of this study was to evaluate the effectiveness and safety of a new colorimetric breath indicator (Colibri, ICOR AB, Bromma, Sweden) in 147 patients during general anesthesia, in critically ill patients, during transport to in-hospital interventions, and in a study design after insertion of a second tube into the esophagus in long-term ventilated patients. The Colibri was attached between the respective airway and ventilatory tubing. Seventy-three patients were investigated during general anesthesia, 39 patients were observed during long-term ventilation with an average duration of 33 hours, in 15 patients during transport to an intervention for up to 4 hours, and in 20 long-term ventilated patients at the medical intensive-care unit after insertion of a second tube intentionally into the esophagus with the help of a laryngoscope. The Colibri worked well in all groups investigated and showed no false results in the group with tubes inserted into the trachea and esophagus. Data suggest that the Colibri might serve as a valuable tool for evaluating and controlling tube position. This device is independent of power supply or electronic equipment, portable, small, and immediately ready for use.