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Biomedical subjects

W Schulte

Publications and source records attributed to W Schulte.

At least 19 recordsLinked to original sources
PubMed1992

Head trauma and the risk of Alzheimer's disease.

A population-based case-control study of the association between head trauma and Alzheimer's disease was conducted in the Netherlands from 1980 to 1987. The study comprised 198 patients with clinically diagnosed early onset Alzheimer's disease and 198 age- and sex-matched population controls. Adjusted for sex, age, family history of dementia, and education, the odds ratio of a history of head trauma with loss of consciousness was 1.6 (95% confidence interval (CI) 0.8-3.4). The odds ratio for men was 2.5 (95% CI 0.9-7.0), and that for women was 0.9 (95% CI 0.3-2.8). The increase in odds ratio was limited to head trauma that occurred within the period of 10 years prior to the onset of dementia (odds ratio = 10.0; 95% CI 1.0-96.8). There was no evidence of effect modification by family history of dementia as measured on a multiplicative scale. However, the power to show interaction may have been low in this study. The authors' findings are compatible with the view that head trauma may be implicated in Alzheimer's disease, with a short lag time between the head trauma and the first symptoms of disease. The association needs to be confirmed in a prospective follow-up study to fully exclude the possibility of recall bias.

Aged↗
PubMed1992

Impact of antihypertensive therapy with isradipine and metoprolol on early markers of hypertensive nephropathy.

In a double-blind, randomized trial with 26 male white patients with essential hypertension in World Health Organization Stages I and II, we examined the impact of calcium entry blockade (5 to 10 mg/day isradipine, N = 14) and beta-blockade (100 to 200 mg/day metoprolol, N = 12) on early markers of hypertensive nephropathy before and after 7 weeks' treatment. Excretion of total protein, albumin, alpha 1-microglobuline, and N-acetyl-beta-glucosaminidase (NAG) were measured in the 24-h urine by radial immunodiffusion and fluorimetric method, respectively. Before therapy, 8 of 26 patients had microproteinuria (31%), six had microalbuminuria (22%), six had elevated urinary NAG activity (22%), and three had elevated alpha 1-microglobulin excretion (11%). In these subjects anti-hypertensive therapy led to a fall in proteinuria (296 +/- 56 v 127 +/- 116 mg/day, P less than .01), albuminuria (44 +/- 24 v 25 +/- 12 mg/day, P less than .05), and NAG excretion (45 +/- 22 v 28 +/- 5, P less than .05). The higher the pretreatment value, the greater the fall was in proteinuria (r = +0.55, P less than .01), albuminuria (r = 0.80, P less than .001), and NAG excretion (r = 0.60, P less than .01). We did not observe any significant difference in clinical characteristics, blood pressure, or urinary excretion of protein, albumin, or NAG between the two treatment groups, either before or after therapy. Thus, antihypertensive therapy reduced excretion of total protein, albumin, and NAG activity in hypertensive patients with elevated pretreatment values, potentially indicating reversal of early hypertensive nephropathy.(ABSTRACT TRUNCATED AT 250 WORDS)

Antihypertensive Agents↗
PubMed1992

High-speed filming of the Periotest measurement.

Periodontal disease may be diagnosed with the Periotest technique, which involves electronically controlled and reproducible percussion of tooth. The movement on percussion was investigated with high-speed film and then compared with the return of teeth after static deflection for several seconds as has been reported previously by Lukas and Scholz. The elastic and viscous properties of the periodontium and the surrounding bony tooth socket are to a large extent non-linear. The 10-20 microns deflection of the healthy tooth represents only a fraction of static tooth mobility published by Parfitt or Schulte et al. The visco-elastic properties of a healthy tooth enabling the percussion of the Periotest tapping head to be decelerated in less than 1 ms are largely lost in periodontitis. It is this essential difference which the Periotest method utilizes.

Alveolar Bone Loss↗
PubMed1992

Periotest for measuring periodontal characteristics--correlation with periodontal bone loss.

The Periotest measures the reaction of the periodontium to a defined percussive force. The percussion is applied to the tooth by an electronically controlled tapping head. Information on structural change is obtained by measurement of both the elastic and viscous characteristics of the periodontium. The latter prevent oscillations of the tooth in the alveolar bone. A value is calculated and is displayed as a "Periotest value". The following research report shows the relation of Periotest values to bone loss. Bone loss was quantitatively determined for 2312 teeth from orthopantomographic radiographs and for 900 teeth exposed to intra-oral films using the standard paralleling technique. A differentiation was made between vertical and horizontal bone loss. Clinical mobility index, pocket depth, gingival recession and papillary hemorrhagic index were also measured. There was a strong association between the Periotest value and bone loss. These results suggest that Periotest evaluation provides an objective indication of the extent of periodontal bone loss.

Adult↗
PubMed1992

The Periotest method.

The Periotest is a new instrument for the diagnosis of periodontal diseases. The 'Periotest value' depends to some extent on tooth mobility, but mainly on the damping characteristics of the periodontium. The Periotest measures the reaction to a reproducible impact applied to the tooth crown. The Periotest value is a biophysical parameter.

Electronics, Medical↗
PubMed1992

Impact of angiotensin converting enzyme inhibition on the haemodynamic profile during laboratory stress tests.

To determine the haemodynamic profile of angiotensin converting enzyme (ACE) inhibitors during stress, the cardiovascular response to various stress tests was examined in patients with essential hypertension before and after three months of therapy with lisinopril. Eighteen white patients were enrolled in the trial, of whom 12 completed the protocol. ACE inhibition with lisinopril effectively reduced systolic and diastolic pressure in the office (P less than 0.001), at rest (P less than 0.002), during mental stress (P less than 0.003), cold pressor test (P less than 0.003), and reaction time task (P less than 0.05). During physical exercise only diastolic pressure was significantly reduced (P less than 0.02). The fall in peak systolic pressure during cold pressor test and reaction time task was more pronounced than the fall in casual systolic pressure (P less than 0.05). At rest, cardiac output was unchanged, but total peripheral resistance was reduced after medication with lisinopril (P less than 0.05). During the cold pressor test, the increase in total peripheral resistance was attenuated by ACE inhibition (P less than 0.04). The haemodynamic response profile was not altered during the other tests. It is concluded that in middle-aged men ACE inhibitors reduce blood pressure during a variety of stressful events without altering the haemodynamic profile and even attenuating vasoconstriction during stress. This response pattern to ACE inhibition with lisinopril may reduce the impact of recurring stress-induced increases of blood pressure and of exaggerated vasoconstrictive stimuli on the cardiovascular system.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1992

Pharmacological modulation of stress-induced cardiovascular hyperreactivity in essential hypertension.

The effects of the calcium antagonist isradipine and the beta-blocker metoprolol, which are based on different antihypertensive therapeutic principles, were evaluated in 52 men with mild-to-moderate hypertension in a 6-week, double-blind, randomized study. Mental stress-testing was performed before and after active treatment. With isradipine (n = 26), the stress-induced responses of cardiac output and total peripheral resistance were not significantly changed, but the blood pressure (BP) response, specifically the diastolic response, was decreased. With metoprolol (n = 26), there was a decreased response of cardiac output and an increased response of total peripheral resistance, and the BP response was even greater than it had been before treatment. Thus, these results indicate that beta-blockade is effective in reducing cardiac responsiveness but, because of vascular counterregulatory mechanisms, BP responsiveness is not decreased. In contrast, calcium antagonism preserves the physiological hemodynamic profile while reducing BP responsiveness to stress.

Calcium Channel Blockers↗
PubMed1991

Contribution to the functional surface structure of endosseous implants.

An endosseous implant that should allow osseointegration as well as fixation by connective tissue has been developed. A special surface structure consisting of titanium wire loops on a titanium implant was produced by diffusion bonding. The mechanical properties of this implant are investigated.

Dental Bonding↗
PubMed1978

[Animal experiments on the question of healing around the Tübingen immediate implant].

In order to determine the capacity for deposition of bone, 5 Beagles were each implanted extraorally with 6 aluminium oxide cylinders into the horizontal mandibular ramus. 4 months after the first implantation a second implantation was carried out in the opposite side with similar cylinders. After six months all were removed so that in altogether 60 implants the bone deposition could be observed 4 months and 2 months after implantation. A further 14 dogs received altogether 55 Tuebinger immediate implants. All animals were regularly observed post-operatively. After 6 months all cylinder full-implants had been accepted without reaction. All tooth implants which were either not put under strain or were immediately put under pressure healed without reaction. After three months 19 implants were lost and a further 5 were lost after 8 months. All cylinder implants were histologically examined 6 months after first implantation.

Animals↗
PubMed1978

[Light and scanning electronmicroscopic studies of border surfaces of aluminum oxide-ceramic implants in the dog mandible].

The mandibular bone of beagles as well as foxhounds and the border surfaces in the area of implants of dense Al2O3 ceramic were examined by scan electron microscope and optically in undecalcified preparations 4 and 6 months after the start of the experiment. All implants healed without foreign body or inflammatory reaction and exhibited a firm contact with the newly-formed surrounding osseous tissue. The border surface was always formed by osseous tissue and bone marrow and not by connective tissue. The bony border surface presented a casting of the structure proper of the ceramics as well as orderly remodelling. The tooth implants which had in part been under strain for a long time were surrounded by newly formed osteoid bone and supported by bone trabeculi. In the immediate proximity of the surface of the ceramic vital osteophites were found. The gum which was placed in a groove of the step implants showed firm epithelial covering and orderly fibrous texture.

Aluminum Oxide↗
PubMed1978

[Concept and testing of the Tübingen immediate implant].

This introductory communication deals with the functional-anatomical, biophysical and neurophysiological considerations which led to the construction of an aluminium oxide immediate implant from a stepped cylindrical body. This intra-osseous implant differs in essential constructional features from the implant shapes known up to now; it endeavours to make use of the architecture of the natural gingival fibre apparatus for the placing of the mucosal cuff. Its surface was maximalised towards the bone, leaving out surface structures which could produce pressure points. The enlargement of surface compared with the root of the corresponding natural tooth amounts to 65 to 100% varying according to the shape of the implant. Descriptions are given of the concept of testing experimental implants, the physical and chemical characterisation of surfaces, animal-experimental steps, clinical tests including legal problems posed and the control system created with the view to large scale clinical trials.

Aluminum Oxide↗
PubMed1978

[The Tübingen immediate implant in clinical studies].

95 Tuebinger immediate implants--four different types--were clinically tested. The longest time of observation was 2 1/2 years. Of the type which so far has been shown to be the best (54 implants), one was lost. The quota of losses was higher in the other types. Preservation depends on the shape of the implant head and particularly on the size of the lacuna. Best results were achieved by the 54 implants with a lacuna radius of 100 micron. Smaller lacunae increase the failure rate.

Bone Regeneration↗