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PubMed1984

Strategy choices by young Braille readers.

The hypotheses that in Braille learning coding strategies change with reading level, and coding differs between normal and retarded readers were tested with oddity judgments by blind children. Experiment 1 showed that strategy choices varied with reading level only in association with mental age. By contrast, shape neglect and preference for phonological strategies were shown by retarded readers rather than by matched normal readers. Experiment 2 showed that under instructions to use given coding strategies the retarded were as accurate as normal readers. Accuracy for all forms of coding increased with reading level, but coding word shape was significantly less accurate than other forms of coding, and even correct coding of shape was no faster than semantic or phonological coding. It is concluded that coding the shape of Braille words is unlikely to be a major factor in producing faster Braille reading, and retarded Braille readers differ from normal readers in their spontaneous choice of strategy rather than in the ability to use the relevant codes.

Blindness↗
PubMed1985

A change in the genetic code in Mycoplasma capricolum.

Mycoplasma capricolum was previously found to use UGA instead of UGG as its codon for tryptophan and to contain 75% A + T in its DNA. The codon change could have been due to mutational pressure to replace C + G by A + T, resulting in the replacement of UGA stop codons by UAA, change of the anticodon in tryptophan tRNA from CCA to UCA, and replacement of UGG tryptophan codons by UGA. None of these changes should have been deleterious.

Anticodon↗
PubMed1979

Evolutionary nucleotide replacements in DNA.

With the increasing availability of analytical information on mRNA molecules, it is now possible to compare homologous nucleotide sequences from different organisms and to draw conclusions about their evolution. Such comparisons have shown that silent changes in codons occur more frequently than nucleotide replacements that produce changes in amino acid sequences (code-altering changes). Furthermore, there is an important difference between amino acid sequence comparisons and nucleotide sequence comparisons. The former show only differences in amino acid residues, but the latter show several types of differences when corresponding codons are compared. Single-base replacements may be degenerate (silent) or expressed as amino acid replacements. Two-base codon changes may be degenerate, single-base changes, or be visible as such. Three-base codon changes may be degenerate (involving serine), simulate either single-base or two-base changes or be visible as such. All nine types of change are found in comparisons of genes from the viruses phi X174 and G4. The relative numbers of these nine types as based on all possible interchanges between all 61 amino acid codons were listed by Holmquist et al. and are shown in Table 1. We discuss these results in the light of the significance of nucleotide changes in molecular evolution.

Base Sequence↗
PubMedDate not supplied

Altered nucleotide sequences of a translocated c-myc gene in Burkitt lymphoma.

The nucleotide sequence of a translocated c-myc gene in a Burkitt lymphoma reveals multiple base changes in the coding region. Twenty-five base changes, generating 16 codon alterations, were found in the first coding exon; no changes occur in the second coding exon. These changes are probably the result of somatic mutations that occurred during and after translocation, and may contribute to oncogenesis by allowing synthesis of an altered c-myc gene product.

Amino Acid Sequence↗
PubMed1992

Six new mutations in the ornithine transcarbamylase gene detected by single-strand conformational polymorphism.

We describe six new mutations in the ornithine transcarbamylase (OTC) gene found in patients with OTC deficiency. These mutations were detected by single-strand conformational polymorphism analysis of amplified genomic DNA and characterized by direct sequencing of double-stranded DNA. Three of the mutations were found in males who had neonatal onset of hyperammonemia. The mutations are a single base deletion (guanine) in exon 5 at nucleotide 403 causing a frame-shift error, a guanine to adenine substitution at the 3' end of intron 2 nucleotide 217 (-1) causing an acceptor splicing site error, and a guanine to adenine substitution at base 236 changing the code from glycine to glutamic acid at position 47 of the mature enzyme. Two different mutations were found in two males whose onset of clinical problems occurred after the neonatal period. One patient had a guanine to cytosine transversion in the sense strand of exon 3 at nucleotide 281 resulting in a substitution of threonine for arginine in position 62 of the mature OTC protein. This substitution changes the composition of the putative active site for carbamyl phosphate from Ser-Thr-Arg-Thr-Arg to Ser-Thr-Arg-Thr-Thr. The second patient has a guanine to thymine substitution at nucleotide 912 of the sense strand of exon 9, changing the code for leucine to phenylalanine in position 272 of the mature OTC protein. This changes a conserved domain of the gene likely to be the ornithine binding site from Phe-Leu-His-Cys-Leu-Pro to Phe-Leu-His-Cys-Phe-Pro.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Metabolism, Inborn Errors↗
PubMed2025

Single-Cell Splicing Isoform Atlas of the Adult Human Heart and Heart Failure.

BACKGROUND: Alternative splicing plays crucial roles in normal heart development and cardiac disease by influencing protein-coding sequences, functional domains, and molecular networks. However, a detailed characterization of the human heart isoform landscape remains incomplete. METHODS: Leveraging long-read single-nucleus RNA sequencing and computational analysis, we dissected full-length isoform heterogeneities, expression patterns, and usage shifts across cell types, cell states, and cardiac conditions of the adult left ventricle. We applied in silico approaches to assess the functional relevance of identified isoforms; validated isoform compositions of representative cardiac genes using reverse transcription quantitative polymerase chain reaction and targeted amplicon sequencing; and developed a web server for interactive navigation of our results. RESULTS: The data revealed that isoform heterogeneity is widespread in the cardiac cellular system, serving as a posttranscriptional buffer mechanism that calibrates the molecule reservoirs in human hearts. In healthy left ventricles, ≈30% of cell type-specific genes were polyform, using multiple isoforms tailored to cell type-specific programs. Among ubiquitously expressed genes, >300 showed differential isoform usage with cell type specificity in normal hearts. Comparisons of cardiomyocytes across conditions uncovered 379 genes with marked isoform usage shifts, most of which are predicted to change protein coding outcomes through direct changes in protein coding sequences and switches between intron retention and non-protein-coding biotypes. In contrast, cell state-specific programs tend to operate on monoform genes associated with changes among cell states. In addition, our data revealed heart failure-associated differential isoform usage events in stromal and immune cell types in the cardiac microenvironment. CONCLUSIONS: We present a comprehensive atlas of splicing isoforms in the normal adult heart and heart failure through long-read single-nucleus RNA sequencing and computational analyses. The results suggest crucial roles of isoforms in buffering core cellular programs and contributing to disease-associated cell states. The full-length details of these cell-specific isoforms serve as an important reference for downstream translational and mechanistic studies and are available on our online data portal at https://github.com/gaolabtools/heart-isoform-atlas.

Humans↗
PubMed1980

[Interpretation of the ECG changes using the Minnesota code in the presence of right-ventricular (high-altitude) cardiac hypertrophy].

The research showed a high incidence of electrocardiographic signs of hypertrophy of the right ventricle of the heart under high-altitude conditions. Code 2-3 was found in 49.2% of highlanders examined, code 2-4 in 1.5%, code 3-2 in 17.0%, and code 9-4-2 in 54.4%. Some cases of hypertrophy of the right ventricle of the heart (code 3-2, approximately 4-5%) are attended by disturbances in the repolarization processes in the right chest electrocardiographic leads (code 5-1 or 5-2). According to the interpretations of the Minnesota code, these shifts should be considered ischemic. But information yielded by the Rouz questionnaire, the results of clinical examination, and tests with maximum physical load in 8 persons who had such shifts on the ECG did not confirm the presence of symptoms of ischemic heart disease. That is why changes in T wave detected in highland aborigenes with marked right-ventricular hypertrophy but no clinical symptoms of ischemic heart disease should be accepted as evidence of ischemia. Otherwise, if the disturbances in the repolarization processes are interpreted as signs of myocardial ischemia, the prevalence of ischemic heart disease among the population of the highlands may be overestimated. The introductin of restriction in relation to code 3-2 when it is combined with code 5-1 or 5-2 will make it possible to study more exactly the true prevalence of ischemic heart disease in the presence of hypertrophy of the right ventricle of the heart.

Adult↗
PubMed1980

Human and murine tumours: changes in cell surface structures coded by the major histocompatibility complex region.

Serological and structural changes of surface markers involved in immune reactions may occur in human and murine tumour systems. Thus nine out of twenty-one human tumour cell lines and SV40-transformed fibroblasts differed from autologous lymphoblastoid cells or fibroblasts in their reactivity with HLA alloantisera. H-2 antigens isolated from the murine tumour cells 6C3HED and TP1422, undergo structural changes. An alien HLA-B7 was detected in sera from two melanoma patients. The serologic activity of H-2 antigens was significantly increased in the serum and ascites fluid of tumour bearing mice. Additionally, human SV40-transformed fibroblasts acquire receptors for monkey red blood cells and the murine lymphosarcoma cells 6C3HED express receptors for sheep red blood cells.

Animals↗
PubMedDate not supplied

The effect of income projection on resident charges for services.

This study examined how family practice residents coded their patient care services, and whether feedback on coding patterns together with income projections would alter coding behavior. Current and future income projections were calculated using assumptions about the practice setting. The collected and calculated data were presented to the residents after the study period, together with a discussion of coding of patient care services and fees. The same data were collected three months and nine months later. There was no significant difference in coding patterns when comparing first- to second- to third-year residents. Six months after the information was presented to the residents, the percentage of brief visits coded decreased significantly, and the percentages of intermediate and comprehensive visits coded increased significantly. Twelve months later, the changes in coding patterns had reverted to the initial findings. This appears to be an effective approach that could be used elsewhere to teach coding of patient care services as part of a practice management curriculum.

Curriculum↗
PubMed1990

Changes in messenger RNAs coding for neurotransmitter receptors and voltage-operated channels in the developing rat cerebral cortex.

The ontogenetic development of poly(A)+ mRNAs coding for receptors to several neurotransmitters (kainate, glutamate, acetylcholine, and serotonin) and voltage-operated channels (sodium and calcium) was studied by isolating total poly(A)+ mRNA from the brains of rats at various developmental stages and injecting it into Xenopus oocytes. The oocytes translated the foreign mRNA and incorporated functional receptor/ion channel complexes into the cell membrane. Thus, recording of induced membrane currents in voltage-clamped oocytes gave a measure of the relative amounts of the different messengers. Responses induced by kainate, glutamate, acetylcholine, and serotonin all increased with age and reached a maximum in oocytes injected with mRNA from adult cortex. Messenger RNAs for the earliest ages examined, Embryonic Days 15 and 18, expressed little or no response to kainate, glutamate, or acetylcholine, while 50-70% of the adult response was reached by Postnatal Day 10. In contrast, the serotonin-induced response was already comparatively large (16% of the adult level) in oocytes injected with mRNA from Embryonic Day 15 brain and increased postnatally to adult levels. The expression of voltage-dependent sodium and calcium channels was small in oocytes injected with mRNA from embryonic animals and increased postnatally to reach a maximum in oocytes injected with mRNA from adult animals.

Aging↗
PubMed1984

Transformation-associated changes in nuclear-coded mitochondrial proteins in 3T3 cells and SV40-transformed 3T3 cells.

Comparative two-dimensional gel electrophoretic studies were performed on mitochondrial proteins in nontransformed mouse 3T3 cells and in SV40-transformed 3T3 cells, SV-T2. Two polypeptides, of 58 and 40 kDa, were present in increased amounts in SV40-transformed cells. These polypeptides were demonstrated to be nuclear-coded mitochondrial proteins by their absence in mitochondrial preparations, when labeling was performed in the presence of a mitochondrial-specific inhibitor, Rhodamine 6G. Temperature-sensitive mutants for transformation were derived from 3T3 cells by transfection with cloned SV40 DNA containing the ts A58 mutation. Increased amounts of the 58 kDa protein were apparent in these cells at the permissive temperature (33 degrees C) compared to the restrictive temperature (39.5 degrees C).

Animals↗
PubMed1977

Vertical eye movement related unit activity in the rostral mesencephalic reticular formation of the alert monkey.

Eye movement related unit activity was recorded in the rostral mesencephalic reticular formation (MRF) of the alert monkey. Most units (78 out of 117) were activated with a short activity burst starting before the eye movement and were otherwise silent. The activity was the same whether movements occurred spontaneously in the light or dark, or were fast phases of vestibular or optokinetic nystagmus, and could be related to parameters of a vector representing the eye movement such as amplitude, position changes along certain planes or direction of movements. Units coding position changes or direction of movement had their preferred direction always close to the vertical. Other units (18 out of 117) showed some tonic activity, which was also only related to vertical eye position. It is suggested that this region of the rostral MRF acts an an immediate supranuclear structure, mediating eye movements in the vertical plane.

Action Potentials↗
PubMed1985

The use of comparability ratios to adjust hospital trend data.

Hospital trend data may be affected by changes in diagnostic coding schemes. We studied the change from ICDA-8 (I-8) to ICD-9-CM (I-9) in a sample of roughly 13,600 double-coded Veterans Administration hospital diagnoses. Comparability ratios were computed and used to adjust trend data which overlap the time period when the shift from I-8 to I-9 occurred. With this adjustment for change in diagnostic coding scheme, apparent diagnostic trends are substantially altered.

Diagnosis↗