[Cosmetic injectables in dental practice: legal aspects in the Netherlands]. / Cosmetische injectables in de tandheelkundige praktijk: juridische aspecten in Nederland.

A recent survey indicates 49% of this journal's subscribers endorse the administration of cosmetic injectables by properly trained dentists. Given the surging demand for cosmetic treatments, it's essential to establish clear guidelines and conventions defining the roles of the various healthcare professionals in various situations. There is, however, considerable discussion still and from a legal standpoint, the role of dentists within cosmetic medicine remains ambiguous. Under the Dutch Individual Healthcare Professions Act (Wet BIG), dentists are authorized to administer cosmetic injectables exclusively for dental purposes. However, based on the content of current dental training, one might argue that dentists' authorization could be extended to include facial injectable treatments in the entire face, in future. Presently, it is prudent for general practice dentists to abstain from cosmetic procedures with cosmetic injectables without a specific (aesthetic) dental objective.

Development of an electrochemical immunosensor for direct detection of interferon-gamma at the attomolar level.

An electrochemical immunosensor for direct detection of the 15.5-kDa protein interferon-gamma (IFN-gamma) at attomolar level has been developed. Self-assembled monolayers (SAMs) of cysteine or acetylcysteine are formed on electropolished polycrystalline Au electrodes. IFN-gamma adsorbs physically to each of these SAMs. With injections of 100 mM KCl, IFN-gamma can be removed in the flow without damaging the acetylcysteine SAM. However, the cysteine SAM is affected by these KCl injections. In an on-line procedure in the flow, a specific antibody (MD-2) against IFN-gamma is covalently attached following carbodiimide/succinimide activation of the SAM. The activation of the carboxylic groups, attachment of MD-2, and deactivation of the remaining succinimide groups with ethanolamine are monitored impedimetrically at a frequency of 113 Hz, a potential of +0.2 V versus SCE, and an ac modulation amplitude of 10 mV. Plots of the real (Z') and imaginary (Z") component of the impedance versus time provide the information to control these processes. In the thermostated setup (23.0 degrees C), samples of unlabeled IFN-gamma (in phosphate buffer pH 7.4) are injected and the binding with immobilized MD-2 is monitored with ac impedance or potential-step methods. While the chronoamperometric results are rather poor, the ac impedance approach provides unsurpassed detection limits, as low as 0.02 fg mL-1 (approximately 1 aM) IFN-gamma. From a calibration curve (i.e. Z" versus the amount injected), recorded by multiple 50-microL injections of 2 pg mL(-1) of IFN-gamma, a dynamic range of 0-12 pg mL(-1) could be derived. However, when nonspecific adsorption is taken into account, which has been found to be largely reduced through injections of 100 mM KCl, a much smaller dynamic range of 0-0.14 fg mL(-1) remains. The immunosensor can be regenerated by using a sequence of potential pulses in the flow by which the SAM with attached MD-2 and bound IFN-gamma is completely removed. When the developed procedures described above are repeated, the response of the immunosensor is reproducible within 10%.

Electrochemical pretreatment of polycrystalline gold electrodes to produce a reproducible surface roughness for self-assembly: a study in phosphate buffer pH 7.4

It has been emphasized in several studies that the state of the surface, including the surface roughness, is very important for the reproducible formation of high-quality self-assembled monolayers on gold. The pulsed-potential pretreatment procedure described in this paper can, in a reproducible way, reduce the surface roughness of mechanically polished polycrystalline gold electrodes by a factor 2. The developed procedure, in which the gold is alternately oxidized and reduced, has been optimized for use in a flow system (100 mM phosphate buffer pH 7.4). The influence of the pretreatment procedure on the surface roughness of the electrodes has been studied by in-situ oxygen adsorption measurements using cyclic voltammetry. The most effective pulse regime in producing a gold surface with a reproducible and relatively low surface roughness is a triple-potential pulse waveform, with potentials of +1.6, 0.0, and -0.8 Vvs SCE and pulse widths of 100 ms for each potential. Prolonged pulsing for 2000-5000 s with the gold working electrode in a flow-through cell showed an electropolishing effect, i.e., a decrease of the roughness in time. Flow conditions are very important: the roughness decreased faster at higher flow rates, while an increase was observed without flow. A process of reconstruction and dissolution of gold during application of the potential pulses under flow conditions is assumed to account for the observed phenomena. A self-assembled monolayer of thioctic acid with reproducible characteristics, determined with impedance measurements, could be formed on a pretreated gold surface.

A protein C pathway (PCP) screening test for the detection of APC resistance and protein C or S deficiencies.

A new automated method for screening defects in the Protein C Pathway (PCP) was evaluated. The "PCP test" is based on a phospholipid-rich Russells viper venom reagent, insensitive to heparin and lupus anticoagulants. To minimize interference from other clotting variables, ratios of the clotting time with and without the addition of a protein C activator were usually determined. Plasma samples from healthy volunteers, patients untreated or on oral anticoagulants, patients with factor V Leiden with and without treatment, and patients with protein C and/or S deficiencies were tested. Mixing patient plasmas 1:1 with individual plasmas deficient in factor V, protein C or S was evaluated for identifying the nature of defects by shortening the screening test. The PCP test was found to be sensitive to APC resistance due to factor V Leiden and by mixing with factor V deficient plasma was also useful despite the effects of oral anticoagulants. Results in the group of patients with previous low protein C or S levels suggest that the method has a better sensitivity to protein C than to protein S deficiency. The automated test was simple to use and gave a between-run coefficient of variation below 3% on normal plasmas.

Body position can be monitored in 3D using miniature accelerometers and earth-magnetic field sensors.

OBJECTIVES: The study and diagnosis of movement disorders can be improved by monitoring body position simultaneously with the EMG. METHODS: We developed a monitor of the 3-dimensional (3D) orientation of body parts that can be applied in long-term ambulatory recordings in the daily life of a patient. The 3D sensor combines miniature sensors for earth's gravity and magnetism. It measures 60 x 50 x 10 mm and draws less than 1 mA of current from +/-5 V battery power. The non-horizontal direction of earth magnetism, as well as torque (pronation) of the body part, is corrected mathematically. RESULTS: This results in a measurement of the 3D orientation of a body part in terms of vertical inclination and horizontal azimuth. CONCLUSIONS: Calibration measurements indicate that this method is fairly accurate and practically applicable.

Double inhibition model for degradation of phenol by Pseudomonas putida Q5.

A semiempirical model, based on the presence of an inhibitory intermediate metabolite excreted to the broth, was developed to better predict the dynamic responses to shock loadings of Pseudomonas putida Q5 degrading phenol. Compared to the Haldane equation, the new model exhibited better prediction capabilities for a broad range of inlet concentration and dilution rate step changes. The experiments were performed at 10 degrees and 25 degrees C and ranged from stable responses to washouts. The time delays observed experimentally were successfully predicted with the dual-inhibition model and a very good agreement with the observed phenol profile also was found in a pulse experiment. A possible intermediate metabolite was detected by HPLC analyses based on the high correlation shown with the predicted inhibitory intermediate metabolite in the model.

Gastric protein breakdown and pancreatic enzyme activities in response to two different dietary protein sources in newly weaned pigs.

Seventy pigs were weaned at 25 d of age and fed diets based on either skim-milk powder (SMP) or soybean protein concentrate (SOY). At 0, 3, 6, and 10 d after weaning, pigs were anesthetized, their pancreases were removed, and digesta were collected from different sections of the digestive tract. The ratio between trichloroacetic acid (TCA)-precipitable protein and total (crude) protein (pp:cp) in gastric digesta was higher with SOY feed than with SMP feed. In the jejunum, no difference was found; hence, the degree of protein breakdown in jejunal chyme did not differ between protein sources. Trypsin activities in jejunal chyme and in pancreatic tissue increased (P < .01) after weaning. Chymotrypsin activity in pancreatic tissue tended to decrease after weaning and did not reach "weaning levels" for at least 10 d. Pancreatic trypsin developed more rapidly than chymotrypsin after weaning. Chymotrypsin activities in jejunal digesta were higher (P < .05) for the pigs fed SMP than for those fed SOY. Protease activities in the jejunum at d 6 after weaning were clearly affected (P < .05) by feed intake after weaning. The ratio between trypsin and chymotrypsin activity in jejunal chyme was higher (P < .05) for SOY-fed pigs than for SMP-fed pigs. It was concluded that the stomach plays an important role in the digestion of milk protein and that the development of pancreatic proteases after weaning (synthesis, secretion, breakdown) depends on feed intake and on dietary protein source.