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Biomedical subjects

S Grossmann

Publications and source records attributed to S Grossmann.

At least 19 recordsLinked to original sources
PubMed2006

The role of toxicokinetics in xylene-induced ototoxicity in the rat and guinea pig.

In the rat, some aromatic solvents cause a high level of ototoxicity that is characterized by damage to outer hair cells in the cochlea, which results in irreversible hearing loss. However, there is a vast difference in their potency. Among the three isomers of xylene, only para-xylene has been shown to be ototoxic in the rat. Moreover, all the species do not show the same susceptibility to ototoxic solvents, the rat being the most susceptible and the guinea pig seeming resistant to this ototoxic effect. The objective of the study was to determine whether toxicokinetic factors could explain the differences in ototoxicity observed among the three isomers of xylene in the rat and the species-dependent ototoxicity in the rat and the guinea pig. Blood and brain concentrations of each isomer were monitored in Sprague-Dawley rats treated orally by gastric intubation with a single dose or a 10 day-repeated treatment of 8.47 mmol/kg (an ototoxic dosage for para-xylene) of each isomer. Moreover, histology of the cochlea was carried out and the toxicokinetics of meta-xylene was monitored in rats treated with a single dose or a 10 day-repeated treatment of 16.94 mmol/kg meta-xylene, a non-ototoxic isomer. Similarly, histology of the cochlea was carried out and the toxicokinetics of para-xylene was followed in guinea pigs treated by gavage with a single dose or a 10 day-repeated treatment of 8.47 mmol/kg para-xylene. Finally, the blood and brain concentrations of para-xylene were measured in both the rats and the guinea pigs after a 4-h exposure to 1800 ppm of para-xylene. Among the three isomers studied, para-xylene yielded the highest blood and brain concentrations in the acutely and repeatedly exposed rats. When given a high dosage of meta-xylene (16.94 mmol/kg), the rats showed blood and brain concentrations of meta-xylene in the same order as those obtained with 8.47 mmol/kg para-xylene, but no outer hair cell loss was observed. No outer hair cell loss was observed in the guinea pigs treated with para-xylene. Whatever the exposure pattern, the blood and brain concentrations of para-xylene in the rats were 3.1-9.5 times higher than those measured in the guinea pigs. These results indicate that toxicokinetic factors cannot explain the differences in ototoxicity observed with the three isomers in the rat. However, they suggest that the differences in susceptibility to para-xylene observed between the rats and the guinea pigs might be due to toxicokinetic factors.

Animals↗
PubMed2006

'Treatise on the Spinal Marrow and its Diseases' (Anatomy, functions and general considerations on its diseases) by Ollivier d' Angers CP (1796-1845).

STUDY DESIGN: Collecting and analyzing all possible documents by internet, and consulting medical libraries in different countries. OBJECTIVE: To focus on the work of Ollivier d'Angers who, in the beginning of the 19th century, spent most of his professional life studying the spinal cord, marrow (SM), or medulla spinalis, and publishing the first comprehensive treatise on the subject in 1824. SETTING: ParaDoc database, Swiss Paraplegic-Centre, 6207 Nottwil, Switzerland, in collaboration with Paul Dollfus, ISCoS/Paradoc, Mulhouse, France. RESULTS: Some of d'Angers's clinical descriptions, observations and also pathologic findings, described in the successive editions of his treatise, were very much in advance of his time. CONCLUSIONS: To our knowledge, this was the first comprehensive treatise, in 1824, at least in France. It gave a clear picture on the matter of the SM and in that period of medical history.

Bone Marrow Diseases↗
PubMed2004

Determination of short-term exposure with a direct reading photoionization detector.

The use of a direct reading photoionization detector (PID) to determine short-term solvent exposures is described in the present paper. To assess the relevance of such a total exposure evaluation it was necessary to compare it with the real concentration of pollutants. This comparison was made by measuring in parallel with the PID determination the concentration of each pollutant using a standard technique, i.e. sampling on charcoal tubes and subsequent analysis by gas chromatography. Laboratory tests showed that the linearity of the answer of the PID is good for many compounds and for a mixture of these compounds. Similar tests were carried out for painters in workplaces with the same good correlations (determination coefficient r2 close to 1) between the PID response and the real concentration of the pollutants measured on the sampling tubes. The use of PID also allowed determination of the exposure profile of the workers and comparison of the short-term exposure to the corresponding limit values. Many cases of the short-term limit values being exceeded were revealed by use of the PID, although very few cases of the long-term limit values have been found by the usual sampling (charcoal tube) and analytical (gas chromatography) methods.

Chemistry Techniques, Analytical↗
PubMed2002

Differential association of polymorphisms in the TNFalpha region with psoriatic arthritis but not psoriasis.

OBJECTIVE: To investigate the potential association of tumour necrosis factor alpha (TNFalpha) microsatellite and promoter alleles with psoriatic arthritis (PsA). METHODS: DNA from 89 white patients with PsA, 65 patients with psoriasis, and 99 healthy white controls was investigated for two TNFalpha promoter (-238 and -308) and three microsatellite polymorphisms (TNFa, c, and d). Patients had previously been studied by serology for HLA class I antigens and by sequence-specific polymerase chain reaction for DRB1* alleles. In addition, TNFalpha production of Ficoll separated peripheral blood mononuclear cells (PBMC) into culture supernatants after stimulation with lipopolysaccharide, alphaCD3 antibodies, phytohaemagglutinin, and streptococcal superantigen C was determined. RESULTS: A significant, HLA class I independent increase of the TNFa6c1d3 haplotype was found in the group with PsA but not among patients with psoriasis (32% v. 8%, pc<0.008; relative risk (RR)=5.3). In addition, patients with PsA showed a marked decrease of the TNF308A promoter allele (6% v. 18%; pc<0.008; RR=3.5) compared with healthy controls, which was independent of the increased frequency of the -238A polymorphism in this group. PBMC from patients with PsA secreted significantly less TNFalpha than cells from patients without arthritis. In particular, the TNFa6 microsatellite was associated with decreased TNFalpha production. CONCLUSION: These data indicate that allelic variations at the TNFalpha locus influence susceptibility to PsA. Decreased production of TNFalpha is at least in part genetically determined and might be related to the development of arthritis. However, the association of the TNF308G allele with the disease also points to other disease related haplotypes with still unknown susceptibility genes.

Adult↗
PubMed2001

Thermal convection for large Prandtl numbers.

The Rayleigh-Bénard theory by Grossmann and Lohse [J. Fluid Mech. 407, 27 (2000)] is extended towards very large Prandtl numbers Pr. The Nusselt number Nu is found here to be independent of Pr. However, for fixed Rayleigh numbers Ra a maximum in the Nu(Pr) dependence is predicted. We moreover offer the full functional dependences of Nu(Ra,Pr) and Re(Ra,Pr) within this extended theory, rather than only give the limiting power laws as done in J. Fluid. Mech. 407, 27 (2000). This enables us to more realistically describe the transitions between the various scaling regimes.

Journal Article↗
PubMed2001

Scaling hypothesis leading to extended self-similarity in turbulence.

A scaling hypothesis leading to extended self-similarity (ESS) for structure functions (the qth order moments of the magnitude of the longitudinal component velocity differences) in isotropic, homogeneous turbulence is proposed. This is done by generalizing the scale variable r to rg(r/L), with a crossover function g. By extending the refined self-similarity, it is shown that the presented scaling also leads to ESS for structure functions of the energy dissipation rate fluctuations, and to ESS bridging relations between velocity and dissipation rate moments. Extended self-similarity on the basis of a universal crossover function g strictly holds toward the outer scale (L) range only. Yet we find at least approximate ESS toward the viscous, inner scale (l) range. Furthermore, the probability densities for the velocity differences and the energy dissipation rate fluctuations which are compatible with this ESS are offered.

Journal Article↗
PubMed2000

Different transcriptional activity and in vitro TNF-alpha production in psoriasis patients carrying the TNF-alpha 238A promoter polymorphism.

Genes encoded on chromosome 6 within the major histocompatibility complex region are thought to play an important role in the pathogenesis of psoriasis. A potential candidate gene is tumor necrosis factor alpha. The tumor necrosis factor alpha promoter contains several polymorphisms including two G-->A transitions at position -308 and -238, which are the most common in Caucasian populations. The TNF238.2 (-238A) allele has been strongly associated with psoriasis. We have investigated the effect of the -238 and -308 variants on transcription of the tumor necrosis factor alpha gene in luciferase reporter gene assays. In addition, peripheral blood mononuclear cells of 47 patients with psoriasis and 43 controls were stimulated with different antigens and mitogens (streptococcal sonicate and superantigen, lipopolysaccharide, phorbol-12-myristate, phytohemagglutinin, CD3 antibodies) and tumor necrosis factor alpha production was measured in supernatants by enzyme-linked immunosorbent assay. The psoriasis-associated tumor necrosis factor alpha promoter allele TNF238.2 showed a significantly decreased transcriptional activity. Peripheral blood mononuclear cells carrying this allele produced significantly less tumor necrosis factor alpha after stimulation with T cell mitogens and streptococcal antigens in comparison to controls. The promoter allele TNF238.2 seems to influence tumor necrosis factor alpha production; a possible role in the pathogenesis of psoriasis has to be further evaluated.

Adult↗
PubMed2000

Multiscale correlations and conditional averages in numerical turbulence

The equations of motion for the nth order velocity differences raise the interest in correlation functions containing both large and small scales simultaneously. We consider the scaling of such objects and also their conditional average representation with emphasis on the question of whether they behave differently in the inertial or the viscous subranges. The turbulent flow data are obtained by Navier-Stokes solutions on a 60(3) grid with periodic boundary conditions and Re lambda = 70. Our results complement previous high Re data analysis based on measured data [A. L. Fairhall, V. S. L'vov, and I. Procaccia, Europhys. Lett 43, 277 (1998)] whose preference were the larger scales, and the analysis of both experimental and synthetic turbulence data by [R. Benzi and co-workers, Phys. Rev. Lett. 80, 3244 (1998); Phys. Fluids 11, 2215 (1999)]. The inertial range fusion rule is confirmed and insight is obtained for the conditional averages (the local dissipation rate conditioned on the velocity fluctuations).

Journal Article↗
PubMed2000

Dementia in rural primary care practices in Lake County, Oregon.

Procedures used in assessing patients with dementia in rural settings are little studied. Among all patients aged 65 years and older in the four primary care practices in Lake County, Oregon, dementia cases were identified from computerized office databases using preselected International Classification of Diseases, Ninth Edition, codes. A semi-structured chart review determined (1) a dementia diagnosis, (2) cognitive and functional domains assessed, and (3) diagnostic studies performed. Of 1540 available records, 30 had dementia. Nineteen of them met National Institute of Neurological and Communicative Diseases and Stroke-Alzheimer's Disease and Related Disorders Association criteria for Alzheimer's disease (AD). Cognitive impairment was documented in 73% of the 51 identified charts and all with AD. Laboratory studies were recorded in 33% overall and in 42% with AD. Neuroimaging was documented in 18% overall and in 16% with AD. The prevalence of documented dementia in these rural practices may be low, possibly because cases of mild dementia may not be labeled as such. Laboratory studies were performed in a minority of cases of dementia.

Aged↗
PubMed1999

Continued fraction representation of temporal multiscaling in turbulence.

It was shown recently that the anomalous scaling of simultaneous correlation functions in turbulence is intimately related to the breaking of temporal scale invariance, which is equivalent to the appearance of infinitely many times scales in the time dependence of time-correlation functions. In this paper we derive a continued fraction representation of turbulent time correlation functions which is exact and in which the multiplicity of time scales is explicit. We demonstrate that this form yields precisely the same scaling laws for time derivatives and time integrals as the "multi-fractal" representation that was used before. Truncating the continued fraction representation yields the "best" estimates of time correlation functions if the given information is limited to the scaling exponents of the simultaneous correlation functions up to a certain, finite order. It is worth noting that the derivation of a continued fraction representation obtained here for a time evolution operator which is not Hermitian or anti-Hermitian may be of independent interest.

Journal Article↗
PubMed1998

[Future occupational plans of patients after orthopedic rehabilitation: how are they expressed? What influences them?].

Perceptions about one's occupational future are regarded as the initial phase in an ongoing process of occupational resettlement towards achieving gainful activity. Actual gainful activity, however, tends to be increasingly dependent on a number of labour market variables. At the end of an orthopaedic rehabilitation measure, 341 patients with pain syndromes of the locomotor system were interviewed concerning their vocational perspectives and notions, and the data obtained were studied in association with anamnestic and psychosocial factors. It is assumed that both plain expectations (such as returning, or not returning, to work) and multi-layered statements alike (such as the dual message of returning and of not returning to work, at first glance incompatible) will frequently be masked in the interview. Distinct, differing patterns were nevertheless found for the various patient groups regarding pain description, pain course, subjective disablement by pain, subjective job burden, subjective well-being, rehab expectations, and judgement of therapy outcome. Similar differences were stated for the social situation, indicated inter alia by (in)capacity for work, or application for benefit award (severely disabled person status, invalidity pension). Pain drawings, pain severity scaling, differentiated description of various pain qualities, the Pain Disability Index, all emerged as useful and practical additional tools in elucidating these patterns.

Adult↗