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Biomedical subjects

S H Schmidt

Publications and source records attributed to S H Schmidt.

At least 19 recordsLinked to original sources
PubMed2002

[A blind bicycle repair man at the Stedelijk Museum: the exhibition and congress 'labour for the disabled' of 1928].

In the 1920's concern about the rising number of disabled unemployed urban poor led to the founding of the AVO (Dutch organization for labour care for the disabled) in 1927. The AVO presented the problem of the vulnerability of the physically and mentally disabled in the labour market as a matter of collective responsibility. At the Amsterdam AVO congress of 1928 expert contributors discussed the economic, social and medical aspects of disability and work. Simultaneously, a museum exhibition aimed at arousing the interest of the general public and at promoting a more understanding attitude towards the disabled. Though the twofold AVO manifestation raised an immediate favourable general response and the subject was put on the political agenda, the subsequent economic recession and war forestalled concrete measures. Essentially it was the first public debate on disability in the Netherlands.

Blindness↗
PubMed1995

Employment after rehabilitation for musculoskeletal impairments: the impact of vocational rehabilitation and working on a trial basis.

OBJECTIVE: To investigate to what extent vocational rehabilitation and working on a trial basis have an impact on employment after rehabilitation. DESIGN: Follow-up survey, conducted in 1991, among all patients, aged 14 to 64, who were treated between 1984 and 1987. SETTING: An out-clinic department of a rehabilitation center in the west of The Netherlands. SUBJECTS: 395 patients (59% of the original sample) participated in the study. They suffer from musculoskeletal impairments due to back pain (41%), brain injury (20%), neurological disorder (12%), trauma to the upper and/or lower extremities (8%), rheumatoid arthritis (7%), or other disorders (12%). No differences were found between those who did and those who did not respond with regard to age, gender, marital status, disorder, work experience, and participation in vocational rehabilitation. MAIN OUTCOME MEASURE: Odds ratio of having a paid job after rehabilitation. RESULTS: Participation in vocational rehabilitation and working on a trial basis depends on age, gender, work experience, and disorder. When statistically controlled for these variables vocational rehabilitation (odds ratio 1.96; 95% confidence interval 1.12 to 3.42) and working on a trial basis (odds ratio 3.26; 95% confidence interval 1.74 to 6.11) proved to have a significant impact on employment after rehabilitation. CONCLUSIONS: The findings suggest that rehabilitation programs that aim specifically at promoting employment for people with disabilities are effective, in particular when they take place in both a laboratory and a natural setting. The validity of this suggestion must be further tested by means of an experimental design.

Adolescent↗
PubMed1994

Experimental cholesteatoma in the rat.

The etiology of cholesteatoma is still enigmatic. Of the current theories, none has been confirmed with adequately convincing evidence. A completely suitable animal model has not hitherto been available and there is still a need for further experimental studies of this entity. As a possible experimental model we suggest dimethyl-benzanthracene induced cholesteatoma in the rat.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1993

Phenol anesthesia of the tympanic membrane in purulent otitis media: a structural analysis in the rat.

In the present study, local anesthetics were applied to the tympanic membrane (TM) of rats following experimentally evoked purulent otitis media (POM). The structure of the TM was evaluated 24 h, 2 weeks and 3 months after application of phenol to a discrete are of the right TM. The left ear was used as a control. POM induced swelling of all tissue layers of the pears tensa. The tissues were invaded by inflammatory cells and disintegrated. The fibrous layer also dissolved, leaving spontaneous perforations. However, phenol on inflamed TMs did not further alter the TM structure. These findings infer that the injurious effect of topical anesthesia on the intact TM is more or less negligible when applied to diseased TMs.

Anesthesia, Local↗
PubMed1991

Tympanic-membrane structure--new views. A comparative study.

In recent years, the rat has attracted increasing interest as an experimental animal in otological research. In the present study, the structure of the rat tympanic membrane (TM) is compared with that of a traditional experimental animal, the guinea pig, and with the human TM. The normal guinea pig TM consists mainly of a single layer of coarse fiber bundles, in contrast to the more solid layers of radial and circular fibers in man and rat. The investigation reveals similar architectural features in the rat and human TM, whereas the guinea pig TM differs structurally.

Aged↗
PubMed1990

Electrophysiological effects of the clinically used local anesthetics lidocaine, lidocaine-prilocaine and phenol on the rat's inner ear.

Local anesthetics, even if applied to the outer ear canal, may still enter the middle ear, running the risk of penetrating the round window. To elucidate the effect of certain topical anesthetics on the inner ear, the round window niche in the laboratory rat's middle ear was exposed separately to lidocaine, lidocaine-prilocaine and phenol. Auditory brain-stem responses (ABR) were recorded at 2, 4, 6, 8, 12, 16, 20, and 31.5 kHz before the application, and 24 h, 3 weeks, 2 months and 6 months after exposure. After terminating the 6-month ABR measurements, the animal were sacrificed and the temporal bones fixed and decalcified for light microscopic analysis. All three drugs affected the ABR thresholds and the cochlear morphology with a pattern characteristic for each drug. At 24 h, all three substances caused severe impairment of ABR thresholds, followed by a period of restitution lasting up to 2 months. Even 6 months after exposure, the ABR thresholds at and above 12 kHz were impaired, as compared with the pretreatment level, for all substances tested. In the lower frequencies the original ABR threshold was reached in the order: (1) lidocaine, (2) lidocaine-prilocaine, (3) phenol. The cochlear structures were unaffected by lidocaine, whereas lidocaine-prilocaine and phenol caused morphological damage which was most pronounced after exposure to phenol. The heterogeneity of the changes in the ABR thresholds suggests differences in the mechanism of action of each type of local anesthetic investigated. The effects following lidocaine were transient. However, clinicians must be aware of the ototoxic potential of both lidocaine and phenol.

Anesthetics, Local↗
PubMed1990

Hydrocortisone delay of tissue repair of experimental tympanic membrane perforations.

The effects of topically applied hydrocortisone on experimental tympanic membrane (TM) perforations in rats were evaluated by otomicroscopy and light microscopy. Standardized TM perforations, occupying the whole upper rear quadrant, were performed, and a 2% hydrocortisone suspension (CORT) was applied once daily for 10 consecutive days. Application of CORT caused a delayed healing pattern, and even at 1 month only 2 of 12 perforations had healed. The keratinizing squamous epithelial cells of the TM appeared hypertrophic, whereas hyperplasia, characterizing a nontreated healing TM perforation, was less prominent. The connective tissue layer of the CORT-treated TM was invaded by abundant inflammatory cells, mainly polymorphonuclear leukocytes. Also, when applied to an intact TM, CORT caused hypertrophy of the epidermal cells and an inflammatory reaction within the TM.

Animals↗
PubMed1989

Toxic effects on inner ear of noxious agents passing through the round window membrane.

The effects on inner ear of Xylocain, EMLA, phenol, endotoxin and hydrocortisone were analysed before treatment and 24 h-6 months after instillation of each drug into the round window (RW) niche, where the substance was left. Inner ear function was determined by repeated auditory brainstem recordings (ABR). All cochleae were analysed morphologically at the light microscopic level. Hydrocortisone, Xylocain and endotoxin caused functional changes without morphological correlates, even at long-term follow-up. In contrast, phenol and EMLA caused both functional impairment and graded morphological damage to the organ of Corti in the basal coil. Outer hair cells (OHC) were more vulnerable than inner hair cells (IHC).

Anesthetics, Local↗
PubMed1988

Structural effects of the topical lidocaine-prilocaine anesthetic Emla on the tympanic membrane.

A eutectic mixture of two anesthetic solutions is that of lidocaine and prilocaine, which is available commercially as Emla (eutectic mixture of local anesthetics). This solution is commonly used in clinics in superficial skin surgery and when inserting intravenous catheters, and we also wanted to determine its surface effects when applied onto the tympanic membranes (TM) of rats and guinea pigs as animal models. The animals were observed by otomicroscopy for 2 weeks up to 5 months after administrations of the anesthetic solution. Tissue specimens were then obtained for light microscopy and fine structural analysis. The application of Emla caused minor structural changes to the rat TM, but hardly any alterations to that of the guinea pig. The changes displayed were an overall increased thickness, with typical submucosal edema but only slight epithelial reaction. In comparison with previous results with lidocaine, phenol and Bonain's solution, Emla seemed to be harmless to the structure of the TM. However, the efficacy of Emla as a topical TM anesthetic remains to be proved in future clinical trials.

Anesthetics, Local↗
PubMed1986

[The aged and job perspectives. An exploration].

The expulsion of older people from the labour market is observed with some resignation by policy-makers. One of the consequences is the lack of opportunities for older people to participate in social life. This process of expulsion started as far back as the mid-sixties. Initially the Disablement Acts, and more recently the Unemployment Acts and Early Retirement measures were used to this end. After describing these processes, attention is paid to the rehabilitation activities for the older people who are entitled to payments according to the Disablement Acts. Some empirical data are presented. It is shown that hardly any activities have been undertaken that result in the rehabilitation of older disabled people. This situation has contributed to create an atmosphere in which the opinion prevails that older people are superfluous in the labour market. Taking into account the development of employment in agriculture, manufacturing and services, there are perspectives for older people to work in the service sector.

Aged↗
PubMed1984

Short-term effects of local anaesthetic agents on the structure of the rat tympanic membrane.

Four different local anaesthetic agents were tested on the tympanic membrane of the rat in order to detect any structural changes. Specimens were obtained for examination under the light microscope 10 min, 24 h, 1 week, and 2 weeks after exposure to each anaesthetic. The histological changes observed were, in general, rather similar for all agents tested, although certain differences were noted. The initial change observed was damage of the outer epithelial layers, later also accompanied by changes in the corresponding endothelial cover. No perforations were observed macroscopically. The healing process was characterized by hyperplasia of the connective tissue layers of the drum. However, the most prominent feature of this process was the hyperplastic epithelium, ingrowing from the periphery of the membrane to cover denuded areas. During certain stages of the healing process the thickness of the membrane amounted to 40 times that of the normal drum. The initial changes appeared severe both with the clinically more potent and effective anaesthetics (phenol and Bonain's liquid), and with Xylocaine spray.

Anesthetics, Local↗
PubMed1984

Short-term effects of local anaesthetic agents on the structure of the rat tympanic membrane.

Topical agents used in office procedures for tympanic membrane anaesthesia have been considered to cause damage to the membrane. Four different anaesthetic agents have been compared as regards their histopathological effects for a period of up to 2 weeks after application. An etching effect is obvious when using these clinically potent agents, but it seems reversible and does not leave remaining structural changes.

Aerosols↗
PubMedDate not supplied

Late effects of local anesthetics on tympanic membrane structure.

With the rat tympanic membrane used as a model, various topical anesthetics in current clinical use (phenol, Bonain's liquid, and Xylocaine spray) were tested. Structural changes were observed for up to five months from the time of anesthetic application. The most protracted changes affect the lamina propria, which exhibits a pronounced thickening. The extent of the changes, however, differs according to the agent used; for example, phenol applied to discrete areas exhibited the least widespread changes. In the tympanic portion of the lamina propria, the connective tissue was loosely packed with less regularly arranged collagen fibers, while a tightly packed fiber bundle existed on the meatal side. It is inferred that the submucosal connective tissue layer is the portion of the connective tissue layer where the remodeling and reconstruction of the fibrous layer occur.

Aerosols↗
PubMedDate not supplied

Fine structure of the rat tympanic membrane after treatment with local anaesthetics.

The tympanic membrane of the rat was studied ultrastructurally after application of a local anaesthetic--lidocaine spray. Already after 10 min, degenerative changes--or even necrosis--were observed on both epithelial surfaces of the eardrum. Later on, a marked hyperplasia of the epidermal layer was most characteristic, as was a proliferation of the fibroblasts of the subepithelial connective tissue. After 3 weeks the eardrum had not regained its normal appearance. No perforations were encountered and only minute substructural changes could be detected within the fibrous layer.

Aerosols↗