Enamel surface alterations after repeated conditioning with HCl.

BACKGROUND: The aim of this study was to investigate the influence of etching time with 15% hydrochloric acid (HCl) on the enamel surface destruction by studying the resulting roughness and erosion depth. METHODS: The vestibular surfaces of 12 extracted, caries free human incisors were divided into four quadrants, and each quadrant was etched with 15% HCl for different numbers of etching cycles (1×2, 2×2, 3×2 and 4×2 min). Surface roughness and erosion depth were measured quantitatively with optical profilometry, and the surface morphology was imaged with scanning electron microscopy (SEM). RESULTS: After two minutes of 15% HCl application a median enamel substance loss of 34.02 µm was observed. Lengthening of etching time (2×2, 3×2 and 4×2 min) resulted in significantly increase in erosion depth to each additionally, between 13.28 -15.16 µm (p < 0.05) ending up in a total median enamel surface loss of 77 µm. Regarding surface roughness no significant (p > 0.05) difference was found between unetched enamel and the etched enamel surfaces. CONCLUSION: Repeated 15% HCl conditioning of the enamel surface increases the depth of the etched surface erosion. However, the total erosion depth is rather shallow and therefore negligible.

Early secondary prevention of occupational skin disease in Germany: the dermatologist's procedure in perspective.

The dermatologist's procedure was introduced in 1972 as a "procedure of early detection of occupational skin disease" by industrial, agricultural and public-sector employers' liability insurance funds of Germany's statutory occupational accident insurance. To date, it represents the most relevant tool for secondary prevention in industrial dermatology in Germany. According to the intention of this procedure, insured parties who are likely to have an occupational skin disease have to be offered preventive measures and, if necessary, given appropriate treatment to avoid job-loss. In co-operation with the Central Federation of the Industrial Professional Associations, the Task Force on Occupational and Environmental Dermatology of the German Dermatological Society, and the Professional Organisation of German Dermatologists, a study group was constituted in 1999 to improve the traditional dermatologist's procedure. In October 2002 a controlled intervention study was started in North-western Germany to establish the definitive value of the "optimised" dermatologist's procedure. Past, present, and future of this specific procedure are discussed.

Characterisation of the expression of a novel constitutive maize promoter in transgenic wheat and maize.

A novel constitutive promoter from the maize histone H2Bgene was recently identified. In this study, we characterised H2B promoter activity in both wheat and maize tissues using the gusA reporter gene and two synthetic versions of the pat (phosphinothricin acetyl transferase) selectable marker gene, namely mopat and popat. Analyses of transgenic plants showed that the H2B promoter is able to drive the expression of gusA to strong, constitutive levels in wheat and maize tissues. Using an H2B:mopat construct and phosphinothricin selection, we recovered transgenic wheat plants at efficiencies ranging from 0.3% to 7.4% (mean 1.6%), and the efficiency of selection ranged from 40% to 100% (mean 77.7%). In another application, H2B was combined with the maize Ubi-1 or the maize Adh-1 intron to drive the expression of mopat and popat. Transformation efficiencies with the Ubi-1 intron were between 1.4- to 16-fold greater than with the Adh-1 intron. However, the use of either of the introns was necessary for the recovery of transgenic plants. Mopat gave higher transformation efficiencies and induced higher levels of PAT protein in maize tissues than popat.

Prospective study on the reproducibility of cephalometric landmarks on conventional and digital lateral headfilms.

The introduction of digital X-ray techniques offered a variety of new possibilities for digital image enhancement and exposure reduction. In order to compare the reproducibility of cephalometric landmarks on conventional and digital lateral headfilms 100 digital and 100 conventional lateral headfilms of patients attending our clinic were randomly selected. The digital cephalograms were obtained using storage phosphor plates in standard X-ray cassettes. All X-rays had been taken at 77 kV. For the digital images the mAs settings for conventional images minus 4 mAs were used. Two orthodontists traced each X-ray twice (21 reference points) at an interval of at least 1 week. The tracings were superimposed and the distances between the tracings of identical reference points were registered. The average reproducibility of cephalometric landmarks was significantly higher on the digitally obtained images, despite a reduction of radiation exposure of 23.7% in the digital images.

The pharmacokinetics and analgesic efficacy of larger dose rectal acetaminophen (40 mg/kg) in adults: a double-blinded, randomized study.

UNLABELLED: Analgesic acetaminophen plasma concentrations are not known. We investigated in a randomized, double-blinded study the pharmacokinetics and analgesic efficacy of small- (AS; 20 mg. kg(-1)) and larger- (AL; 40 mg/kg) dose rectal acetaminophen and compared it with the combination (C) of rectal diclofenac (100 mg) and acetaminophen (20 mg/kg) in 65 women undergoing hysterectomy. Suppositories were administered after the induction of a standardized general anesthesia. Pain (measured by using a 10-cm visual analog scale) and morphine consumption (patient-controlled analgesia) were repeatedly assessed for 24 h. Acetaminophen plasma concentrations were measured by using a fluorescence polarization immunoassay. Antipyretic plasma concentrations (10-20 mg/L) after 40 mg/kg acetaminophen were not associated with improved analgesia or decreased opioid requirements; 20 mg/kg acetaminophen produced subtherapeutic plasma levels (<10 mg/L). Maximal plasma concentrations of 17.2 and 10.4 mg/L (P < 0.01, analysis of variance) were achieved after 4.2 and 3.6 h for the AL and AS groups, respectively. The only difference in clinical outcome was lower visual analog scale scores after acetaminophen/diclofenac (C 2.0 versus AS 3.2 and AL 3.4) 4 h after the induction (P < 0.05, analysis of variance). Acetaminophen pharmacokinetics in adults were similar to those observed in children. Analgesic plasma concentrations are likely to be higher than antipyretic plasma levels, which were only attained after twice the recommended rectal dose was administered. Analgesic plasma concentrations have yet to be determined but may be higher than those associated with antipyresis. IMPLICATIONS: Acetaminophen pharmacokinetics were comparable in adults and children. Plasma concentrations known to reduce fever did not produce better pain relief and were only achieved after twice the conventional dose was administered. Analgesic plasma concentrations have yet to be determined but may be higher than those associated with antipyresis.

Structural analysis of a plant sucrose carrier using monoclonal antibodies and bacteriophage lambda surface display.

Monoclonal antibodies were raised and selected against recombinant Plantago major PmSUC2 sucrose carrier protein. Epitopes of two monoclonal antibodies (PS2-1A2 and PS2-4D4) were mapped using N-terminally truncated PmSUC2 proteins and a lambda library displaying random PmSUC2 peptides. PS2-1A2 recognizes an octapeptide close to the N-terminus of PmSUC2, PS2-4D4 binds to a decapeptide at the very C-terminus. Analyses of antibody binding to yeast protoplasts with functionally active, tagged PmSUC2 protein revealed that both epitopes are located in cytoplasmic domains of PmSUC2. These results support a model for plant sucrose transporters containing 12 transmembrane helices with the N-terminus and the C-terminus on the cytoplasmic side of the plasma membrane.

Monoclonal antibody-based enzyme immunoassay for the quantitative determination of the tropane alkaloid, scopolamine.

A monoclonal antibody (SP1-4-A2) against scopolamine was produced, characterized, and used to develop a sensitive and selective, competitive enzyme immunoassay for the quantitation of the alkaloid. The assay uses nor-scopolamine-N-beta-propionic acid coupled to alkaline phosphatase as tracer and is linear from 10 pg to 10 ng of scopolamine. As little as 10 pg of scopolamine can be quantitated in an unprocessed plant extract or in human serum after suitable dilution, corresponding to detection limits of 0.1 ng scopolamine/ml of plant extract or 0.5 ng/ml of serum. The assay is more selective for scopolamine (percent cross-reactions for hyoscyamine = 0.21%, 6-hydroxy-hyoscyamine = 0.17%) than previously reported immunoassays. The assay format was designed to minimize intra- and inter-plate variabilities which are, on an average, all below 3% (coefficients of variation). The assay reported here has been validated against an HPLC-based technique using plant samples and was shown to correlate closely (y = 0.959 x + 0.14, r = 0.982).

[Atenolol poisoning]. / Intoxikation mit Atenolol.

A 44-year-old obese female patient ingested 200 mg diazepam and 1000 mg atenolol with suicidal intent. On admission to the clinic 24 hours later she was in deep coma, with a body temperature of 28.9 degrees C. The blood level of atenolol was 250 mg/l (therapeutic range 0.2-0.5 mg/l); this is the highest level yet recorded. She was treated with gastric lavage, instillation of charcoal and with orciprenaline, dopamine and dobutamine. She survived the poisoning without any untoward sequelae.

[Electrocardiogram in acute anterior wall infarct after restoration of the blood supply]. / Das Elektrokardiogramm beim akuten Vorderwandinfarkt nach Wiederherstellung der Blutversorgung.

Changes in QRS complexes and ST-T segments were measured in 70 patients after acute anterior-wall myocardial infarction. Intracoronary streptokinase infusion was undertaken in the acute phase in 58 patients, 12 other patients treated conventionally without infusion serving as controls. Precordial ECG mapping employed 48 unipolar precordial leads. If recanalization of an occluded coronary artery was achieved, there was a significant rise in R amplitude (sum of R-wave amplitudes in the 48 leads) from 12.4 +/- 10.9 to 16.2 +/- 11.2 mV, within a period of up to four months after the acute stage. If thrombolysis failed or only conventional treatment had been practised, there was no rise in R-wave amplitude. Renewed occlusion of a vessel previously re-opened by streptokinase infusion produced a reduction in R-wave amplitude from 14.0 +/- 13.0 to 9.8 +/- 11.0 mV. The S-T segment elevation regressed immediately after recanalization of the coronary artery. The S-T segments were iso-electric after four months. Re-occlusion caused renewed S-T segment elevation up to monophasic form. Precordial ECG mapping is thus well suited for serial controls after various re-perfusion measures.

Left ventricular ejection power in coronary artery disease during atrial pacing.

Peak and mean left ventricular ejection power were measured during atrial pacing in 6 normal subjects (group I), 6 patients with coronary artery disease without myocardial infarction (group IIa), and 10 patients with coronary artery disease after myocardial infarction (group IIb). Pacing rates were 80 and 120/min. Power was determined by computer analysis of pressure, volume, and time. Data were normalised by end-diastolic volume and left ventricular muscle mass. Peak left ventricular ejection power normalised by end-diastolic volume values at a pacing rate of 120 min were significantly lower in group IIa and IIb than in normal subjects. Mean muscle mass in normal subjects was 179 g and in group IIa 216 g (P smaller than 0.05). Peak power normalised by muscle mass in normal subjects tended to increase at 120/min whereas in group IIa it declined by 26 per cent (P less than 0.001). These data indicate that the energy output of the left ventricle at rest may be the same in patients with significant coronary artery disease as in normal subjects. Increasing the heart rate from 80 to 120/min in a normal myocardium augments power but in coronary artery disease it remains static or falls.

[Infleunce of heart cycle length on left ventricular ejection fraction in normals and patients with coronary artery disease]. / Der Einfluss der Periodendauer auf die Ejektionsfraktion des linken Ventrikels bei Gesunden und Patienten mit Koronarer Herzkrankheit.

The ejection fraction is a clinically valuable index of left ventricular pump function. We investigated the influence of a change in heart cycle length in normals (gr. I) and in patients with coronary artery disease without (gr. IIa) and after myocardial infarction (gr. IIb) (atrial pacing 80 and 120 min-1). In all subjects ejection time decreased by ca. 17%. There was no statistical difference between the groups. Ejection fraction (mean absolute values): gr. I (n = 7): - 3.4% (n. s.), gr. IIa (n = 8): - 8.4% (p is less than 0.01), gr. IIb (n = 12): - 6.5% (p is less than 0.01), Gr. IIa + IIb: - 7.2% (p is less than 0.001), gr. I +IIA + IIb: - 6.1% (p is less than 0.001). Compared to the control value the relative decrease for all subjects was -12.3 +/- 12.0% (n = 27). When left ventricular performance is evaluated by ejection fraction using invasive and noninvasive methods (contrast medium ventriculography, echocardiography and scintigraphy) heart cycle length has to be taken into account. The data cannot be normalized by a simple mathematical procedure.

[Haemodynamic effects of nefopam (author's transl)]. / Hämodynamische Wirkung von Nefopam.

The haemodynamic effects of nefopam (0.3 mg/kg i.v.) were measured for 45 minutes in ten patients with coronary heart disease. The drug is a new and highly potent analgesic without any respiratory depressant effect. Arterial blood pressure and cardiac output rose moderately, while left ventricular enddiastolic pressure remained unchanged. Heart rate did not exceed 91/min. Max dp/dt, min dp/dt, Vpm and V40 rose by a maximum of 16% above control. Thus nefopam differs from other potent analgesics in having a slight inotropic effect.

[Angiography of the left ventricle using right atrial injection (author's transl)]. / Kontrastmitteldarstellung des linken Ventrikels nach Injektion in den rechten Vorhof.

Left ventricular angiography as a diagnostic means is of considerable importance in the evaluation of myocardial and valvular dynamics. The injection of contrast medium into the left ventricle often causes premature ventricular contractions. In these cases quantitative analysis of the contraction pattern is impossible. This can be avoided by injection of the contrast medium into the right atrium. The technique described allows to obtain ventriculograms which meet the criteria for quantitative angiocardiography. 57 ventriculograms have been performed in 32 patients with various cardiac abnormalities. The study describes the technical procedure, the indications and limitations. Furthermore special applications are discussed (videometry, pressure-volume relationship).