PubMed Health⌕ Search

Biomedical subjects

J Niemi

Publications and source records attributed to J Niemi.

10 recordsLinked to original sources
PubMed1992

On the nature of naming difficulties in aphasia.

An extensive naming battery was administered to ten patients representing classical aphasia syndromes. The battery included traditional performance measures and error scoring, phonological cuing, multiple-choice tasks tapping semantic and phonological knowledge, and word repetition tests. Differences in the patients' performance profiles were interpreted as reflecting lexical-phonological, phoneme assembly or multiple deficits. The results suggest that the hypothesized naming deficits have complex relationships to classical aphasia syndromes.

Adult↗
PubMed1992

abaA, a new pleiotropic regulatory locus for antibiotic production in Streptomyces coelicolor.

Production of the blue-pigmented antibiotic actinorhodin is greatly enhanced in Streptomyces lividans and Streptomyces coelicolor by transformation with a 2.7-kb DNA fragment from the S. coelicolor chromosome cloned on a multicopy plasmid. Southern analysis, restriction map comparisons, and map locations of the cloned genes revealed that these genes were different from other known S. coelicolor genes concerned with actinorhodin biosynthesis or its pleiotropic regulation. Computer analysis of the DNA sequence showed five putative open reading frames (ORFs), which were named ORFA, ORFB, and ORFC (transcribed in one direction) and ORFD and ORFE (transcribed in the opposite direction). Subcloning experiments revealed that ORFB together with 137 bp downstream of it is responsible for antibiotic overproduction in S. lividans. Insertion of a phi C31 prophage into ORFB by homologous recombination gave rise to a mutant phenotype in which the production of actinorhodin, undecylprodigiosin, and the calcium-dependent antibiotic (but not methylenomycin) was reduced or abolished. The nonproducing mutants were not affected in the timing or vigor or sporulation. A possible involvement of ORFA in antibiotic production in S. coelicolor is not excluded. abaA constitutes a new locus which, like the afs and abs genes previously described, pleiotropically regulates antibiotic production. DNA sequences that hybridize with the cloned DNA are present in several different Streptomyces species.

Amino Acid Sequence↗
PubMed1990

Cloning and expression in a heterologous host of the complete set of genes for biosynthesis of the Streptomyces coelicolor antibiotic undecylprodigiosin.

A fragment of DNA carrying the hitherto unisolated members of the cluster of genes (red) for biosynthesis of the red-pigmented antibiotic undecylprodigiosin of Streptomyces coelicolor A3(2) was isolated. This was done by cloning random fragments of S. coelicolor DNA into the closely related Streptomyces lividans 66 and recovering a clone that caused overproduction of undecylprodigiosin. The effect was probably due to the presence of the cloned redD gene, which functions as a positive regulator of the expression of the red cluster, activating the normally poorly expressed red genes of S. lividans. Two fragments from either end of the red cluster were cloned adjacent to each other on a low-copy-number Streptomyces vector. Double crossing-over occurring between these plasmid-borne sequences and the chromosomal copy of the same DNA in S. coelicolor led to isolation of the entire red cluster as a single cloned fragment. Isolation of antibiotic biosynthetic genes by the effects of an activator in a self-cloning experiment, and in vivo reconstitution of a large cluster of genes by homologous recombination, may turn out to be usefully generalizable procedures.

Cloning, Molecular↗
PubMed1990

Semantic errors in a deep dyslexic.

A case of a Swedish-speaking deep dyslexic is reported whose semantic paralexias appeared to result mainly from a lexical retrieval failure in oral reading. He was able to draw correct pictures of the written words for which he had simultaneously produced a semantically erroneous oral reading response. Repeated attempts to correct paralexic responses were common, indicating that the patient was often aware of the errors. His lexical retrieval problems and semantic errors extended to naming as well, and the results support Nolan and Caramazza's (1982, Brain and Language, 16, 237-264), dual-deficit model of deep dyslexia.

Adult↗
PubMed1988

Fragile X speech phonology in Finnish.

Fragile X syndrome is a recently discovered relatively common syndrome linked with an anomaly of the X chromosome and causing handicaps of cognitive development especially in males. In the present phonological analysis we will discuss the sound patterns of two Finnish fragile X speakers, a five (borderline intelligence)- and an eight (mildly mentally retarded)-year-old boy. The fragile X syndrome is not necessarily linked with any anomalies of speech organs. The subjects could produce all Finnish speech sounds in isolated test words. However, in the present samples of connected speech they exhibited general dysphonology. What is noteworthy is that their phonological error patterns resembled each other to a great extent. Among the common features were the tendencies to substitute and omit phonemes. As for vowels, our results showed about one-half of the errors to be omissions. Labiality and quantity oppositions were quite resistant to substitution. Most substitution errors of place of consonants occurred in dentals. As for the feature of manner, /r/ and /s/ were the phonemes most prone for substitution. A tendency toward spirantization or /h/ sation was common for both patients. The number of additions was clearly lower than has been reported for English-speaking developmentally dyspraxic children and also for Finnish Broca's aphasics. The speech problems of our patients seemed to indicate higher level motor encoding problems of linguistic information rather than peripheral articulatory deficits.

Articulation Disorders↗
PubMed1988

Grammatical morphology in aphasia: a case of errata or reader misinterpretations?

As convincing as the discussion presented by Elizabeth Bates, Angela Friederici and Beverly Wulfeck on grammatical morphology in aphasia in three languages may seem, we were at loss when trying to reconstruct the quantitative basis of their argumentation (see Bates et al., 1987, Grammatical morphology in aphasia: Evidence from three languages. Cortex, 23: 545-575). With the present notice we would like to lessen the possibility of reader misinterpretations that may easily confuse the thread of the argument of this article in the form in which it was originally presented.

Aphasia↗
PubMed1987

Temporal delay and lexical retrieval in narratives: aphasiological observations.

Temporal delays in nonpathological speech have been mostly attributed to long-term planning and lexical access. In wake of the recent increased interest in lexicon in general, there have also been serious attempts to approach lexical processes through analyses of disrupted lexicon, most notably through the language of aphasics. In the present study we have analyzed the temporal delays and pauses associated with neologisms produced by Finnish posterior aphasics. It appears that delays and pauses correlate with the type of neology they precede. Moreover, the anomia theory of neologistic items will receive here further observational support.

Anomia↗
PubMed1986

A new approach to high sensitivity differential hybridization.

We describe a new approach to differential hybridization, designed to identify cDNA clones representing rare mRNA species. Duplicate filters carrying a library of cDNA from phorbolmyristate acetate (PMA)-induced EL-4 cells in lambda gt11 were hybridized with high concentrations of unlabeled, cloned, single-stranded cDNA from induced and control EL-4 cells, respectively. Plaques binding single-stranded cDNA were revealed by a second round of hybridization with 35S-labeled DNA complementary to the vector moiety of the single-stranded cDNA. Plaques corresponding to PMA-induced mRNAs occurring at a level of about 1 part in 15,000 were isolated. We believe the method is at least ten times more sensitive than conventional differential hybridization.

Animals↗
PubMed1985

Phoneme errors in Broca's aphasia: three Finnish cases.

The phonemic errors of three Finnish Broca's aphasics were analyzed according to various phonological features, frequency of segments, syllable, word, and stress positions, as well as for the phonotactic structure of the uncanonical products. It was found, e.g., that the distance between the syntagmatic error and its source could not be satisfactorily counted by phonemes, since the syllable had to be taken into account also in pathological Finnish. As regards the paradigmatic dimension of the errors, the number of incorrect features is even here in reverse relation to the frequency of the erroneous phonemes. Moreover, it was found that pure quantity errors and vowel harmony deviations are infrequent in the speech of Finnish Broca's aphasics.

Adult↗