In a series of experiments on 12 normotensives and 12 essential hypertensives the influence of traffic noise (81 dB) on autonomous functions after stress exposure was examined. The process of the stress reaction was started by visually presented arithmetic tasks under affecting noise. With normotensives and hypertensives this combination of stressors led to a significant increase of the systolic and diastolic blood pressure, heart rate, and muscle tone. The influence of traffic noise directly following the combination of stressors was examined in an intraindividual comparison with a resting-time period. During the period of noise, significantly higher values with blood pressure data only were found with normotensives and hypertensives as well. The comparison between the normotensive and the hypertensive group during the combination of stressors and during the following resting period showed no significant differences in reaction whereas during the second stressor hypertensives compared to normotensives showed strong, partly significant adaptation reactions of blood pressure with regard to the preceding experimental phase.

Adult↗

PubMedDate not supplied

Basal blood pressure variability and reactivity of blood pressure to emotional stress in essential hypertension.

Blood pressure variability under basal conditions and blood pressure reactivity to emotional stress were studied in 38 hypertensives and 13 normotensives. Systolic basal blood pressure variability correlated with systolic blood pressure reactivity. Variability increased with higher basal blood pressure. Thus in the hypertension group the blood pressure variability was greater than in the normotension group. Besides, the hypertension group showed a greater reactivity of systolic blood pressure to emotional stress, too. An influence of age on basal blood pressure, blood pressure variability, and reactivity could be evaluated; but no influence of sex on these parameters was detected. The results indicate that variability and reactivity of blood pressure can be referred to a common central nervous blood-pressure-regulating mechanism. As both parameters are increased in hypertension, a greater lability of blood pressure must be assumed. This greater lability may be attributed to a stronger neurogenic influence or to structural changes of peripheral blood vessels.

Adult↗

PubMedDate not supplied

Action of the major protease from Entamoeba histolytica on proteins of the extracellular matrix.

The action of the major protease from the parasitic protozoon Entamoeba histolytica, a cysteine protease of Mr 27,000-29,000, on some important proteins of the extracellular matrix has been studied. The isolated protease degraded the extracellular matrix proteins from human tissue collagen type IV and V as well as laminin and fibronectin with different velocities and specificities under native conditions. Whereas the degradation of fibronectin and laminin proceeded rapidly, yielding distinct fragment patterns, the breakdown of the collagen types happened more slowly and incompletely. The digestion of the denatured isolated alpha 2-chain of bovine collagen type I was very fast and unspecific requiring only 1/10 of the enzyme activities as compared with the other substrates mentioned above. Nearly 85% of the overall proteolytic activity of a soluble fraction of E. histolytica was strongly inhibited by antibodies against the purified histolytic protease as well as by cystatin from chicken egg white, a specific protein inhibitor of cysteine proteases. We conclude that the histolytic protease represents by far the highest portion of soluble proteolytic activity in E. histolytica which is sufficient to destroy the extracellular matrix of the host.

Animals↗

PubMedDate not supplied

Pinch-off syndrome: a rare etiology for central venous catheter occlusion.

BACKGROUND: Catheter pinch-off syndrome is a rare and often misdiagnosed complication of tunneled Silastic central venous catheters. Pinch-off syndrome occurs when the catheter is compressed between the first rib and the clavicle, causing an intermittent mechanical occlusion for both infusion and withdrawal. We report its incidence in a large series of catheter insertions and describe the clinical presentation, radiographic findings, and recommended treatment. METHODS: A total of 1457 tunneled Silastic central venous catheters that were inserted using the percutaneous subclavian approach were prospectively studied. Indications for catheter placement included bone marrow transplant, continuous or intermittent chemotherapy, long-term antibiotics, and parenteral nutrition. Catheters were evaluated for clinical presentation of an occlusion relieved by postural changes and radiographic findings of luminal narrowing. RESULTS: Pinch-off syndrome was identified in 16 (1.1%) catheters. Radiographic findings were present in all catheters; clinical findings were present in 15 catheters. Clinical symptoms presented within a median of 2 days after placement (range, 0 to 167 days). Partial or complete catheter transection, a serious sequela of catheter pinch-off syndrome, occurred in 19% of the identified catheters. CONCLUSIONS: (1) Catheter pinch-off syndrome presents clinically as a catheter occlusion related to postural changes; (2) clinical symptomatology should be confirmed radiographically; and (3) catheter removal with a more lateral replacement in the subclavian vein or in the internal jugular vein will avoid a recurrent complication.

Anti-Bacterial Agents↗

PubMedDate not supplied

Area-dependent enlargement ratios of panoramic tomography on orthograde patient positioning and its significance for implant dentistry.

The aim of this work was to study the behavior of vertical and horizontal enlargement ratios in panoramic tomography in various implant regions of the maxilla and the mandible. A method is presented that admits determination of regional enlargement ratios as a function of the implant region. Clearly defined characteristics of the implant body (Frialit-2 implants) are used as reference points. The vertical enlargement ratio varied between 1.21 and 1.29 on optimal orthograde adjusted tomographs, depending on the measured area. The horizontal enlargement ratio at the coronal end of the implant varied between 1.15 and 1.35. As it is below the vertical value in the lateral tooth area, this contributes to the distortion of the implant structures depicted. The horizontal enlargement at the apical end of the implant varies between 1.12 and 1.44. The difference in horizontal enlargement ratios also causes a distortion of the implant structures shown on the panoramic tomograph. Based on this study scenario, panoramic tomography may be well suited to preimplant diagnosis, particularly in the vertical dimension. With regard to transparent templates designed for implant placement, an enlargement of 1.3 in the perpendicular line and 1.35 in the horizontal line is proposed.

Aluminum Oxide↗

PubMedDate not supplied

Immediate postextraction implant placement with root-analog stepped implants: surgical procedure and statistical outcome after 6 years.

The present study investigated 124 stepped-screw implants (gritblasted and acid-etched surface) placed in 104 patients immediately after tooth extraction or implant explantation and followed between August 1990 and December 1996. Implants of varying diameters and lengths were used to cover a wide range of indications in both the maxilla and mandible; 68% of the implants supported single-tooth replacements. The study parameters included Plaque Index, Gingival Index, probing depth, Periotest values, and peri-implant bone loss. Statistical analysis according to Kaplan-Meier revealed a 97% survival rate.

Acid Etching, Dental↗

PubMedDate not supplied

[The teaching of psychiatry in Germany].

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Education, Medical↗

PubMedDate not supplied

The Frialit-2 implant system: five-year clinical experience in single-tooth and immediately postextraction applications.

In an observational study of 696 Frialit-2 implants in 376 patients that was carried out between 1990 and 1995, implants of varying diameters and lengths were delivered for a range of indications in the maxilla and mandible. Single-tooth replacement was performed in 42% of cases; of these, 22.4% were placed immediately following extraction. Study parameters (Plaque Index, Gingival Index, probing depth, Periotest value, and peri-implant bone loss) are reported in detail. Statistical analysis is based on a 97.6% rate of recall. The overall success rate was found to be 96% using the Kaplan-Meier statistical analysis. No difference was apparent between single-tooth applications and prosthesis restorations.

Adolescent↗