Biomedical subjects

B Hermelin

Publications and source records attributed to B Hermelin.

At least 19 recordsLinked to original sources

PubMed1995

Recurrent and novel LDL receptor gene mutations causing heterozygous familial hypercholesterolemia in La Habana.

The molecular basis of familial hypercholesterolemia (FH) in three families of Spanish descent from La Habana was investigated by the candidate gene approach. The Arg3500Gln mutation of apolipoprotein B-100 was not found. Identification of low density lipoprotein receptor (LDLR) gene haplotypes segregating with FH guided the characterisation of three point mutations by automated sequencing. One, a Val408-->Met missense mutation, a founder mutation in Afrikaner FH patients, was recurrent, being associated with a distinct DNA haplotype. The other two, Glu256-->Lys and Val776-->Met missense mutations, were novel and modified highly conserved residues. These mutations were absent in normolipidemic subjects and were associated in heterozygous carriers with twice the cholesterol levels observed in non-carriers. Noticeably, cardiovascular complications were rarely observed in older heterozygotes, even in those with the Afrikaner FH-2 mutation. These findings confirm the molecular heterogeneity of LDLR gene mutations causing FH and the variability of their expression across different populations.

Adolescent↗

PubMed1995

Savants, segments, art and autism.

This study describes two experiments which investigate pattern construction by graphically gifted, autistic savants. We explore whether the notion of weak central coherence in autism might be extended to account for the relatively high frequency of savants among the autistic population. We also suggest that an awareness of constituent segments in wholes may be relevant to artistic talent in general.

Adolescent↗

PubMed1994

Two autistic savant readers.

Two young autistic children of normal intelligence were tested repeatedly for their reading ability. Their comprehension was appropriate for their developmental status, however, they had reading speeds that were considerably faster than those of their age-matched normal controls. Randomizing word order, and thereby reducing meaningfulness, resulted in an equivalent reduction in relative reading speeds for the younger autistic subject and his control. For the older of the normal children, the effect of randomizing word order was very marked, whereas its effect was minimal for the older of the two autistic boys. The results are regarded as an indication that efficient grapheme-phoneme conversion is a modular component of the reading skill and this transcoding process is primarily responsible for the fast reading of the autistic children.

Aptitude↗

PubMed1994

Visual and motor functions in graphically gifted savants.

Savant artists represent a conundrum to our understanding of the nature of high level specific talents as well as to the concept of general intellectual impairment. In the present paper, we are particularly concerned with the relationship between general perceptual-motor functions in relation to drawing aptitude. Drawing is by definition a perceptual-motor operation, yet mental handicap tends to be associated with some degree of impairment in this area. The following study seeks to isolate such aspects of performance on general perceptual-motor skills that might be associated with drawing ability, and may thus be regarded as building blocks underlying the manifestation of graphic talent. The results are discussed in terms of the relationships between graphic talent, non-verbal intelligence and visual-motor functions.

Adolescent↗

PubMed1994

Preliminary results of Pneumocystis carinii strain differentiation by using molecular biology.

The mode of Pneumocystis carinii transmission is controversial. Recent studies point to exogenous inoculation rather than reactivation, and person-to-person transmission has also been suggested. Comparison of nucleotide sequences of the large-subunit mitochondrial rRNA gene of P. carinii from human immunodeficiency virus-seropositive patients showed strain differences.

AIDS-Related Opportunistic Infections↗

PubMed1994

Phosphorylation of vimentin is an intermediate step in protein kinase C-mediated glycoconjugate secretion.

We have previously shown that fibroblasts from patients with cystic fibrosis (CF) display a higher response to 4 beta-phorbol 12-myristate 13-acetate (PMA) than control fibroblasts for stimulation of both protein kinase C (PKC) cytosol-to-membrane translocation and glycoconjugate secretion. In this study we took advantage of these cells with differential responsiveness to PMA to investigate the endogenous substrate(s) involved in PKC stimulation of glycoconjugate secretion after verification of cystic fibrosis transmembrane conductance regulator gene expression in control and CF fibroblasts. We show that a 57-kDa protein that was associated with cytoskeleton and was identified as vimentin by immunoblotting emerged as a good candidate for mediating PKC stimulation of glycoconjugate secretion. 1) Its phosphorylation by PMA was abolished by PKC inhibition or depletion. 2) In both control and CF fibroblasts, the PMA-induced increase in its phosphorylation preceded the phorbol ester stimulation of glycoconjugate secretion. 3) For both processes, the concentration-response curves were superimposable, with higher maximal levels for CF fibroblasts relative to controls. 4) PMA-stimulated 57-kDa protein phosphorylation, like PMA-stimulated glycoconjugate secretion, was significantly increased by Ca2+. 5) Increased PMA phosphorylation of the 57-kDa protein as a result of okadaic acid inhibition of intracellular phosphatases was reflected in increased PMA stimulation of glycoconjugate secretion. In conclusion, 1) PMA phosphorylation of a cytoskeletal 57-kDa protein, identified as vimentin, appears to be an intermediate step in PKC stimulation of constitutive glycoconjugate secretion in human skin fibroblasts; and 2) this process is impaired in CF disease.

Base Sequence↗

PubMed1993

Bottle, tulip and wineglass: semantic and structural picture processing by savant artists.

Semantic and structural aspects of picture processing were investigated with graphically gifted mentally handicapped subjects and intellectually normal children. The results suggest that savants as well as controls rely primarily on semantically organised memory schemata when reproducing pictures. A semantically determined strategy also determines picture sorting. The findings indicate that within the domain of expertise there appears to be no difference between savants and normals regarding the nature of the mental structures underlying specific talents. The mental structures on which such talents are based, should therefore be regarded as being relatively independent of the level of general cognitive functioning.

Adolescent↗

PubMed1992

Do young calendrical calculators improve with age?

The calendrical calculation performance of two 10-year-old children of the same intelligence level (IQ 90) but different calendrical ability, was compared with the performance of eight adult idiot-savant calculators. The calculating speeds of the two 10-year olds fell within the range of the reaction times of the adult savants. No improvement was detectable in a series of successive trials over time, either in speed or accuracy. It is concluded that the young calculators have already inferred rules about calendrical structure and that their performance cannot be accounted for by practice alone, but these savants use cognitive strategies to aid their performance.

Adolescent↗

PubMed1991

Pericellular glycoconjugates of cultured fibroblasts from control and cystic fibrosis patients.

1. Labeled glycoconjugates released by trypsin from cell surfaces of control and cystic fibrosis (CF) skin fibroblasts were purified and fractionated by column chromatography on Sephadex G-50 and Concanavalin A Sepharose. Based on chemical analysis and specific enzymatic digestions: (1) Glycoconjugates were characterized as O-linked glycopeptides consisting predominantly of glycosaminoglycan type and N-linked glycopeptides with glycans of complex type. Their relative proportions were similar between the two groups. (2) The N-linked glycopeptides exhibited an increased molar ratio of fucose to galactose in CF fibroblasts. (3) When pericellular glycoconjugates were metabolically labeled with [14C]glucosamine and [3H]fucose, incorporation and degradation kinetics were similar between the two groups.

Carbohydrates↗

PubMed1991

Talents and preoccupations in idiots-savants.

The question was asked whether a diagnosis of autism or a tendency to repetitive behaviour and preoccupation with a restricted area of interest, were crucial features of idiot-savant talents. Answers by caretakers to a questionnaire on these topics revealed that autistic and nonautistic savants resembled each other closely in preoccupation but differed from controls matched for IQ and diagnosis. In addition, the mentally handicapped showed fewer repetitive tendencies than did autistic controls. It is concluded that independent of diagnosis, preoccupations and repetitive behaviour appear to be closely associated with the manifestation of idiot-savant talents.

Aptitude↗

PubMed1991

Regulation of secretion in cultured tracheal serous cells by protein kinases A and C.

We recently reported that cultured gland serous cells release chondroitin sulfate proteoglycans (CSPGs) in response to beta-adrenergic agonists. In this study, we analyzed this regulatory pathway and other cellular mechanisms responsible for CSPG secretion. We show the following. 1) Isoproterenol increased CSPG secretion in a concentration-dependent manner, with maximal stimulation (50%) obtained at 10(-5) M; at this concentration, the beta-agonist also stimulated protein kinase A (PKA) by 50%, whereas it increased cellular adenosine 3',5'-cyclic monophosphate (cAMP) content by 300%. 2) Phenylephrine (10(-5) M), 4 beta-phorbol 12 beta-myristate 13 alpha-acetate (1.6 x 10(-7) M), and A23187 (10(-6) M) also stimulated CSPG secretion; this stimulation was concomitant with protein kinase C (PKC) translocation from cytosol to membrane, was blocked by sphingosine (2 x 10(-5) M), and was additive with that elicited by isoproterenol. 3) All PKC activators potentiated the isoproterenol-induced increased in cAMP accumulation without modifying the activation of PKA elicited by the beta-agonist. Our results indicate that although the signaling pathways triggered by alpha- and beta-adrenergic agonists converge at the level of adenylate cyclase in tracheal serous cells, PKA and PKC independently regulate CSPG secretion.

Animals↗

PubMed1991

A specific linguistic ability.

A young man with diagnosed hydrocephalic brain injury was found to be an able linguist. His ability to translate into English from French, German, and Spanish was confirmed to be at a high level, and his capacity to express thoughts and describe scenes in these languages was also verified. A set of translations of the Peabody Picture Vocabulary Test was prepared in French, German, and Spanish, and IQs were derived in each language. The subject's performance intelligence was tested separately and found to be low, especially in relation to spatial reasoning. The subject's linguistic achievements were discussed in terms of an IQ-independent linguistic talent.

Adult↗

PubMed1990

Further evidence for abnormal protein kinase C regulation of macromolecule secretion in fibroblasts from cystic fibrosis patients.

In comparison to skin fibroblasts from normal subjects, those from patients with cystic fibrosis (CF): (1) bound [20-3H] phorbol 12,13-dibutyrate (PDBu) with a higher affinity Kd = 25.8 vs 12.8 nM respectively) but expressed a similar number of total phorbol ester binding sites (about 2.5 pmol PDBu bound/mg of protein); (2) exhibited a faster and higher response to 4 beta-phorbol 12 beta-myristate 13 alpha-acetate (PMA) for the stimulation of [35S]-labelled glycoconjugate release, but were equally sensitive to the synergistic effect of A23187 on this process; and (3) secreted glycoconjugates with similar [35S]-sulfate and [14C]-leucine to [14C]-glucosamine labelling ratios. Taken together, these results provide further evidence for abnormal protein kinase C (PKC) regulation of macromolecule secretion in CF disease.

Binding Sites↗

PubMed1990

Factors and primes: a specific numerical ability.

An autistic young man and a normal control were asked to factorize numbers and to recognize and generate primes. Both subjects made a similar number of errors and employed similar strategies, but they differed markedly in the speeds at which the arithmetical operations were carried out.

Adult↗

PubMed1990

The recognition failure and graphic success of idiot-savant artists.

Three groups of subjects, an idiot-savant group, a group of mentally handicapped subjects matched for IQ, and normal artistically gifted children, were compared for their recognition and graphic reproduction abilities. It was found that, independent of input modality, level of intelligence determined recognition performance, while graphic ability independent of IQ was the determining factor in reproduction accuracy.

Adolescent↗

PubMed1990

Art and accuracy: the drawing ability of idiot-savants.

The accuracy and the artistic merit of drawings produced by graphically gifted idiot-savants and by artistically able normal children were investigated in various conditions. Drawings had to be executed when a three- or two-dimensional model of the scene to be drawn was in view, or when it had to be remembered or drawn from another viewpoint. It was found that overall accuracy was better for the normal than for the mentally handicapped subjects. In contrast, ratings for artistic merit did not differentiate the groups. It is concluded that while the accuracy of drawings may be related to intelligence, the artistic quality of the graphic production is not.

Adolescent↗

PubMed1989

Intelligence and musical improvisation.

We investigated whether somebody with a severe mental impairment could not only remember and reproduce music, but was also able to generate it. Musical improvisation requires the ability to recognize constraints and also demands inventiveness. Musical improvisations on a traditional, tonal and also on a whole tone scale composition were produced by a mentally handicapped and by a normal control musician. It was found that not only the control but also the handicapped subject could improvise appropriately within structural constraints, although with the tonal music the idiot-savant showed some stylistic latitude. It is concluded that cognitive processes such as musical input analysis, decision making, and output monitoring are independent of general intellectual status.

Adult↗

PubMed1989

The memory structure of autistic idiot-savant mnemonists.

The memory organization of six autistic mnemonists was investigated in two experiments. The first of these provided some evidence that the material of special interest to the subjects, in the present instance bus numbers, was stored in memory in a categorized form. The second study showed that though the idiot-savant mnemonists did not differ from controls in the level of their general memory performance, the factor structure of a number of memory tests differed between the groups. In contrast to the controls, a verbal memory factor which seemed independent of measured verbal IQ was operative in the mnemonist subjects.

Adolescent↗