Effects of treatment on antibody titer to Porphyromonas gingivalis in gingival crevicular fluid of patients with rapidly progressive periodontitis

Twenty-eight patients diagnosed as having rapidly progressive periodontitis (RPP) were enrolled in a study in which samples of subgingival microflora were harvested from test teeth and assayed for the presence of Porphyromonas gingivalis, and GCF collected and analyzed by ELISA for specific antibody for P. gingivalis. Clinical conditions were measured and recorded, and treatment by scaling and root planing provided at baseline and at 3, 6, 9, and 12 months. Reduction in pocket depth, stabilization of attachment level, and resolution of inflammation were comparable to previously reported values. By 3 months, mean and median specific antibody concentration had decreased, and continued to decrease through 12 months. The proportion of samples in which specific antibody was not detectable increased from 27% at baseline to 73% at month 12. GCF samples from sites at which P. gingivalis was present had greater than 2-fold higher median specific antibody than samples from P. gingivalis-negative sites. At baseline, specific antibody titer of 30-second GCF samples positively correlated with pocket depth, and GCF volume significantly correlated with antibody titer and concentration, and with pocket depth. In addition, change in specific antibody titer of 30-second samples from baseline to both 6 and 12 months correlated positively with pocket depths. Thus sites infected by P. gingivalis manifested high levels of specific antibody, and levels were related to clinical status. Following treatment, antibody levels decreased significantly as pocket depths decreased, attachment levels stabilized, and inflammation resolved.     

Block of the endplate acetylcholine receptor channel by the sympathomimetic agents ephedrine, pseudoephedrine, and albuterol

Recent observations suggest that some patients with congenital myasthenic syndromes respond favorably to ephedrine, pseudoephedrine, or albuterol. Conventional microelectrode studies, however, provide no clear explanation for a beneficial effect of ephedrine in endplate diseases. To gain further insight into how these drugs affect neuromuscular transmission, we investigated their effects on the kinetic properties of the acetylcholine (ACh) receptor. Single channel currents were recorded from rat lumbrical muscles endplates using low concentrations of ACh and 2.5-100 microM of drugs. Between 10-100 microM, each drug progressively increased the rate of channel closure in a concentration dependent manner, consistent with an open-channel block. Albuterol acted as a sequential fast-acting channel blocker, increasing the mean burst duration in a concentration dependent manner without altering the total open time per burst or the duration of intraburst blockages. Increasing concentrations of ephedrine and pseudoephedrine also increased the number of intraburst closures but decreased the total open time per burst. None of the drugs altered single channel conductance. The channel blocking effects of ephedrine and pseudoephedrine might reduce the synaptic overactivity that occurs in the slow-channel myasthenic syndromes or in endplate ACh esterase deficiency, but these effects occur at concentrations not attainable in clinical practice.     

Treatment of uterine fibroids with a slow-release formulation of the gonadotrophin releasing hormone antagonist Cetrorelix

A depot preparation of the third-generation gonadotrophin-releasing hormone (GnRH) antagonist Cetrorelix (SB-75) was used for preoperative treatment in twenty premenopausal patients with symptomatic uterine fibroids who were to undergo surgery. In a prospective, open, randomized setting 60 mg of Cetrorelix pamoate salt was administered i.m. on cycle day 2. Patients were randomized for a second dose of 30 or 60 mg of Cetrorelix depot, which was administered according to the degree of oestradiol suppression (<50 pg/ml) on treatment day 21 or 28. Surgery was done after 6 or 8 weeks of treatment, depending on second dosage administration. Weekly transvaginal sonography (TVS) and magnetic resonance imaging (MRI) before and after treatment was performed, for fibroid volume assessment. Sixteen patients showed satisfactory suppression of gonadotrophins and sex steroid secretion, avoiding any initial flare-up effect. In these patients a mean shrinkage rate of largest fibroid volume of 33.5% at the end of treatment could be observed according to TVS, while the mean shrinkage rate obtained after 14 days of treatment was 31.3%. In good responders (shrinkage >20%) largest fibroid volume at day 14 was approximately 56.7% of basic assessment. Although MRI showed minor mean shrinkage rates of only 25.4% of the initial volume, these differences in comparison to TVS assessment were not statistically significant. The avoidance of any initial flare-up in gonadotrophin secretion may explain this extremely fast reduction in fibroid size. The advantages of GnRH antagonist treatment in this indication consist in the short treatment time with a fast restoration of the ovarian function. The rate of poor responders may be reduced by using an improved slow release preparation.     

Direct percutaneous transluminal coronary angioplasty in acute myocardial infarction. Predictors of short-term outcome and the impact of coronary stenting. Study Group of The Arbeitsgemeinschaft Leitender Kardiologischer Krankenhaus?rzte (ALKK)

BACKGROUND: Direct percutaneous transluminal coronary angioplasty (PTCA) is widely accepted in the treatment of acute myocardial infarction since excellent results had been reported from several small randomized trials. Less favourable results were observed in large-scale registries. In particular, the use of stents in acute myocardial infarction has become common practice without documented evidence of clinical efficacy. METHODS: Data were analysed from a registry of all consecutive percutaneous transluminal coronary angioplasty procedures from 62 centres in Germany, including 2331 direct percutaneous transluminal coronary angioplasty in acute myocardial infarction from July 1994 to April 1997. RESULTS: The overall angiographic success rate of percutaneous transluminal coronary angioplasty, defined as complete antegrade perfusion of the infarct vessel, was 87%. In-hospital mortality was 11.2%. The most important predictor of death was the presence of cardiogenic shock in 15% of patients, of whom 52% died. Mortality in patients without shock was 3.9%. Failed percutaneous transluminal coronary angioplasty was associated with a mortality of 36%. Further independent predictors of death were older age, multivessel disease, and anterior myocardial infarction. Stents were used in 4.1% of the procedures in 1994, increasing to 53% in 1997. However, this was not accompanied by improved clinical outcome. Mortality with coronary stenting was 9.9% vs 11.6% without stents (ns). CONCLUSIONS: Direct percutaneous transluminal coronary angioplasty is a valuable treatment strategy in acute myocardial infarction, although the results are less exceptional than reported from some highly specialized centres. Failed percutaneous transluminal coronary angioplasty seems to be harmful, thus outweighing much of the benefit from successful procedures. Stents did not improve the clinical outcome significantly, despite technically successful placement in 98%. Mortality from cardiogenic shock continues to be excessively high despite direct PTCA.     

Note on Particle Velocity in Collisions Between Liquid Drops and Solids

Equations are developed for plane-wave particle velocity produced in solid-against-liquid collisions. An explicit expression for the dimensionless coefficient α that appears in these equations is deduced.Collisions between liquid drops and the planar surfaces of solids have become important in the present era of high-speed flight. Except for the pressure that results when a drop of incompressible liquid collides with the planar surface of an unyielding solid [1],¹ exact hydrodynamic treatments of the various aspects of this type of collision have not been developed. Plane-wave theory has been used in several approximate treatments [2, 3, 4]. One of the unknowns encountered in the use of plane-wave theory for solid-against-liquid collisions was the particle velocity in the compressed zones.During collision between a solid rod A having flat ends and moving with velocity V in the (+z)-direction of a stationary coordinate system (fig. 1) and a similar liquid rod B that is at rest, there is a radial flow of liquid at the impacted end of rod B. In order that the rods remain in contact while the compressional waves initiated by the collision move through them, the interface velocity (I) must obey the inequality V−v′ >v where v′, v are the particle velocities in the compressed zones.Open in a separate windowFigure 1Collision between a plate moving at velocity V and a liquid drop at rest idealized as collision between a solid rod A and a liquid rod B.We can then write α(V−v′)=v where α is a dimensionless coefficient having a value less than one, and v + αv^′ = αV.(1)Using the relation that exists between stress and particle velocity for plane waves, the equality of stresses at the surfaces of contact is given by zv = z^′v^′, (2)where z is the acoustic impedance (product of sound speed and density). From eq (1) and (2), the particle velocities v, v′ are found to be v = αz^′V/(z^′ + αz)(3) v^′ = αzV/(z^′ + αz), (4)and the plane-wave stress σ is given by σ = σ^′ = αzz^′V/(z^′ + αz).(5)The quantity that must be determined to make these equations useful is the coefficient α.One of the approximate treatments in which plane-wave theory was used for solid-against-liquid collisions [3] provides a means of deducing an explicit expression for the coefficient α. In this treatment the complicated situation of collision between a moving target plate and a relatively stationary liquid drop was idealized as the simple case of the collision of two rods with flat ends. If a plate is fired against a drop (fig. 1), a core of material extending through the plate under the contact area is slowed down with respect to the remainder of the plate and a similar core of material through the drop is set in motion. The cores were regarded as true cylinders free to move in the z-directions (fig. 1) but restrained laterally. The compressional waves that move through the cylinders were regarded as plane waves.With use of this simple model, an equation was developed that gives pit depth δ′ as a function of impingement velocity V for collisions of metal target plates with liquid drops [3]. For impingement velocities for which elastic recovery of the plate is complete, the pit depth was taken to be the product of a numerical constant, the particle velocity given to the cylindrical core of material under the collision area, and the time that the particle velocity exists. The particle velocity was taken to be zV/(z+z′), which is the plane-wave particle velocity for solid-against-solid collisions. The time during which the particle velocity exists was taken to be 2d/c where d is the diameter of the drop and c is the sound speed of the liquid of which it is composed. Therefore, δ′ = (constant) (d/c) [zV/(z+z′)].The pit-depth equation that was developed was applied first to collisions of mercury drops and waterdrops with target plates of copper, 1100–O aluminum, 2024–O aluminum, steel, and lead. The constant was found empirically to be 7.2. The equation was then found to apply without change of the constant to collisions between metal target plates and soft ductile metal spheres that flowed during and as a result of the collision.The same equation was later applied [4] to collision of steel spheres against target plates of 1100–O aluminum, 2024–O aluminum, and copper. It was found empirically that if the target plate was struck by a rigid hardened steel sphere that did not flow as a result of the collision the constant was 17.5.The constants found for the pit-depth equation for the case that a target plate collides with a liquid drop or soft ductile metal sphere and for the case that it collides with a rigid hardened steel sphere provide a means of obtaining an explicit expression for the coefficient α. The two cases differ only in the particle velocity given to the core of material through the target plate. The particle velocity v′ for solid-against-solid collisions was used in each case. The particle velocity v′ for solid-against-liquid collisions should have been used for the case that the target plate collided with a liquid drop or with a soft deforming metal sphere that would flow as a result of the collision.Because it is the particle velocity given to the core of target material under the collision area that is different, and because the constant 7.2 is 0.41 of the constant 17.5, it follows that αzV/(z′+αz) = 0.41 zV/(z′+z) from which α = 0.41/[1 + (0.59 z/z^′)].(6)Values of α calculated with use of eq (6) for collisions of waterdrops and mercury drops with target plates of aluminum, copper, lead, and glass are given in 2]. It was found experimentally [2] that 0.00118 sec were required for a glass plate to move through a 0.57-cm-diam waterdrop when the relative impingement velocity was 820 cm/sec (26.9 ft/sec). The velocity at which the plate moved through the drop was 484 cm/sec. It was assumed that no particle velocity was given to the cylinder of glass through the plate under the collision area. Then the velocity at which the plate moved through the drop was (1−α)V. To this degree of approximation (1−α)820 = 484 and α = 0.4.Table 1Some values of the coefficient α

Prostatic needle biopsy: comparison of needles

To clarify the advantages of the 2 most commonly used biopsy needles results of 100 routine needle biopsies of the prostate are evaluated. The series includes patients selected for study concerning the medical treatment of benign prostatic hyperplasia.