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Biomedical subjects

A Robinson

Publications and source records attributed to A Robinson.

At least 433 records · Page 24Linked to original sources
PubMed1982

Short communication: skeletal maturation of children with sex chromosome abnormalities.

Skeletal maturity, or "bone age," is one of the several criteria used to determine developmental or physiologic age as opposed to chronologic age. The purpose of this study of skeletal maturation of children with sex chromosome abnormalities (45,X, 47,XXX, 47,XXY, X-chromosomal mosaics) and controls is 2c-fold: (1) to investigate if children with sex chromosome aneuploidy ascertained in an unbiased fashion differ in skeletal maturation from their siblings and other normal healthy children born in Denver, Colorado, and (2) to assess if the skeletal age standards currently in use (Greulich-Pyle; Tanner- Whitehouse) are applicable to Denver children when evaluating radiographs for skeletal maturation. Mean chronologic and skeletal age were measured. Mean differences between skeletal and chronologic age for all groups across all measures were calculated. The 45,X females constitute the only group studied with bone ages lower than expected (0.05 greater than P greater than 0.01; two-tailed test). We found no other significant differences in skeletal maturation between Denver children with sex chromosome abnormalities and their siblings or the control sample of Denver children. Although we found the Tanner-Whitehouse standards to be more applicable for use with this population, all the Denver groups investigated yielded consistently lower bone ages than expected published norms. This is the first documentation in a group of children with sex chromosome abnormalities, ascertained in an unbiased fashion, that, with the exception of those with a 45,X karyotype, bone age is not significantly different from that of the normal population.

Adolescent↗
PubMed1982

DNA ligase and DNase activities in mouse erythroleukemia cells during dimethyl sulfoxide-induced differentiation.

DNA ligase and DNase levels were measured in cell-free extracts from untreated mouse erythroleukemia (MEL) cells and from cells treated with dimethyl sulfoxide (Me2SO) to induce erythroid differentiation. The DNase activity present in the extracts was sensitive to inhibition by G-actin and was, therefore, presumed to be DNase I. When the MEL cells were induced to differentiate by culturing in the presence of 1.8% Me2SO for 3 or 4 days, the apparent activity of the DNA ligase decreased to approximately 12% of the value in untreated MEL cells. In contrast, the apparent DNase I activity of the extracts from Me2SO-treated cells increased over that in extracts from untreated cells by a factor of 2. The activity of acid phosphatase, a lysosomal enzyme, remained unchanged. When strain DR-10, a mutant of the MEL cells which does not undergo Me2SO-induced differentiation, was treated with Me2SO, the DNA ligase and DNase activities of extracts from these cells remained unchanged as compared to extracts from untreated DR-10 cells. Therefore, the marked increase in the level of DNA ligase activity appeared to be related to the process of differentiation in the Me2SO-treated MEL cells.

Animals↗
PubMed1982

Learning disabilities in children with sex chromosome anomalies.

Studies of clinical populations have suggested that genetic factors may be involved in the etiology of learning disabilities. The present study included 44 children (ages 7-16) with sex chromosome anomalies (SCA) who were identified in a 10-year sex chromosome screening of all newborns in 2 large hospitals and thus represents an unbiased sample of children with a genetic etiology. 17 chromosomally normal siblings are included as controls. All subjects were given IQ and achievement tests, and extensive, repeated school histories were taken from parents and school personnel. Results demonstrate that SCA children are at an increased risk for encountering learning problems and receiving special education intervention in school. Furthermore, the nature of the learning disabilities may be karyotype specific, although the results are not invariant within karytypes. 45,X children demonstrate a visuo-spatial deficit as evidenced by lower-performance IQ scores and an increased incidence of handwriting problems, while 47,XXY children experience a verbal language deficit seen in lower verbal IQs and a tendency toward more reading delays. 47,XXX children demonstrate a more global delay crossing most cognitive skill areas, although retardation is rare. Mosaic children are relatively unaffected by their karyotypic variations and hence serve as a second control group which guards against the effects of a negative self-fulfilling prophecy. It is concluded from this evidence that learning disabilities can have a genetic basis, although the specific biological mechanism that affects cognitive development in this population remains elusive.

Child↗
PubMed1981

Amniocyte clones for prenatal cytogenetics.

Amniotic fluid cells were processed in situ on coverslips in 1,429 consecutive cases from Colorado and Arizona. Two true chromosome mosaics were differentiated from 39 pseudomosaics with clarity by the method described here in detail. The culture failure rate was 1--2% and the error rate was 0% in both laboratories. The time in culture prior to the initial harvest for the last 329 cases was 8.7 days.

Amniotic Fluid↗
PubMed1981

Familial pericentric inversion of chromosome 8.

Eight children from seven presumably unrelated families were identified independently as having an unbalanced recombinant chromosome resulting in the presence of extra material on the short arm of a chromosome 8. Parental chromosomes were analyzed, and one member of each couple (four fathers and three mothers) was found to carry a pericentric inversion of a chromosome 8 [inv(8)(p23q22)]. The propositi had an unbalanced recombinant chromosome [rec(8),dup q,inv(8)(p23q22)]. The affected infants all had developmental delay, congenital heart disease, and unusual appearance. A common origin of the pericentric inversion was suggested because of geographic location and Mexican--American ancestry of the seven families.

Child↗
PubMed1981

Histological changes elicited in Schistosoma japonicum infected rabbits following curative chemotherapy with 4-isothiocyano-4'-nitro-diphenylamine (C9333-Go/CGP 4540).

New Zealand white rabbits were infected with 250 or 500 cercariae of the Philippine-Leyte strain of Schistosoma japonicum. 26 weeks later the experimental group were given one dose of 25 mg/kg formulated CGP 4540. Six weeks after dosing the treated rabbits and untreated controls were killed and examined. Parasitological cure was complete in all those treated. The liver and intestinal granulomata were greatly diminished in size and there was a dramatic decrease in the number of inflammatory cells in the hepatic tissue.

Aniline Compounds↗
PubMed1981

9;22;15 complex translocation in Ph1 chromosome positive CML revealed by Giemsa-11 procedure in apparent lymphoid cells of blastic crisis.

A Ph1 chromosome positive chronic myeloid leukemia patient whose chronic phase lasted 7.5 years experienced a blastic transformation originating in the spleen. The spleen was infiltrated with undifferentiated blast cells that on cytogenetic analysis had a hyperdiploid karyotype and were Ph1 chromosome positive. The blast cells were negative for PAS, peroxidase. Sudan black and esterase stains. They were non-T, non-B with TdT activity. Remission was achieved in response to prednisone, vincristine, and adriamycin. Ph1 positive cells were present with cells responding to PHA stimulation throughout the course of the disease. A Giemsa-11 staining procedure male possible the ascertainment of a No. 9 translocation chromosome in blastic crisis cells that had also been present in Ph1 chromosome positive cells early in the disease. The presence of this translocation initially in myeloid cells and subsequently in apparent lymphoid cell types suggests the origin of this patient's leukemia as a pluripotential stem cell.

Azure Stains↗
PubMed1981

Development of eight pubertal males with 47,xxy karyotype.

The increasing frequency with which the diagnosis of the 47,XXY karyotype is made requires more knowledge of the prognosis of this condition. We present four 47,XXY boys identified at birth and followed since then (Group I), and four 47,XXY boys diagnosed because of physical and/or emotional problems (Group II). Physical, psychological, language, and hormone data are presented. The physical and intellectual profiles for the two groups are similar. This is in contrast to the very poor school and emotional adjustment of the Group II individuals. These boys were definitely more difficult and problematic for their parents when compared to their siblings and to Group I who were unselected. This further emphasizes that the expression of this karyotype is variable and individuals with behavioral disorders may represent a maladaptive subgroup rather than the entire population of 47,XXY males. Recommendations are given for intervention with attention to learning and language problems, hormone status, and emotional state.

Adolescent↗
PubMed1981

Effect of growth rate and nutrient limitation on the transformability of Escherichia coli with plasmid deoxyribonucleic acid.

The observed transformation frequency by plasmid deoxyribonucleic acid of Escherichia coli grown in continuous culture was found to depend on both the steady-state growth rate and the type of nutrient used to limit growth. With carbon, nitrogen, or phosphorus limitation, the faster the growth rate, the higher the transformation frequency. The increase in transformation frequency associated with higher rates was shown to be due to more transformable cells in the population rather than an increased efficiency of deoxyribonucleic acid uptake. Growth rate had relatively little effect on the transformability of cells from sulfate- and Mg2+-limited chemostats, indicating that some factor other than the growth rate must influence the frequency of transformation. Regardless of the nutrient limitation or the growth rate, no transformants were obtained in the absence of CaCl2.

Calcium Chloride↗
PubMed1981

Homodicentric chromosomes: a distinctive type of dicentric chromosome.

This report describes two patients with a distinctive type of dicentric autosomal chromosome formed by breakage and union between homologous chromosomes. These stable chromosomes possess two C bands, implying the presence of two centromeric regions. The first child, evaluated for dysmorphic features was shown to have an abnormal chromosome 16, designated as 46, XX, -16, + dic (16) (pter leads to cen leads to q22::p11 leads to qter). The second case is a child with the typical features of trisomy 18 whose karyotype is designated as 46, XX, -18, + dic (18) (qter leads to p11.1 :: p11.3 leads to cen leads to qter). The stability of these chromosomes is presumably in result of centromere suppression and associated premature centromere division of the suppressed centromere. The possible mechanism of formation of these homodicentric chromosomes is presented, and a comparison is made between them and three patients with dicentric X chromosomes.

Abnormalities, Multiple↗
PubMed1981

Biofeedback and behavioral approaches in Japan.

A number of studies and case histories involving the use of biofeedback and behavioral approaches throughout Japan have been selected from Japanese journals and summarized. Areas of biofeedback research covered are experimental, clinical and psychological/educational. The behavioral approaches mentioned have been limited to those currently being used in Japan in conjunction with various biofeedback modalities. A brief explanation of a new biofeedback-monitored multi-modal psychosomatic therapy approach developed in Japan, termed cybernation therapy, is also presented along with current Japanese thought on the use of biofeedback in psychotherapy.

Arousal↗
PubMed1981

An X-linked disease of the nervous system with disordered copper metabolism and features differing from Menkes disease.

We studied 2 of 4 affected boys with a new disease associated with abnormalities of copper metabolism. The four cases occurred in two generations of a family. This syndrome was similar to Menkes disease in some respects: X-linked recessive inheritance, marked psychomotor retardation with seizures, low serum copper and ceruloplasmin levels, and a block in gut copper absorption. There were also striking differences from Menkes disease. Patients had normal birthweight at term, no hypothermia, and survived beyond the usual Menkes age group with static neurologic disease including hypotonia and choreoathetosis. In addition, general examination of both children was unremarkable apart from undescended testes and growth retardation. The hair, facies, and skin were normal and there was no radiologic evidence of bony changes. Detailed studies of copper absorption were performed.

Brain Diseases, Metabolic↗
PubMed1980

Acute isoniazid poisoning in childhood.

Acute isoniazid poisoning is uncommon in children. Only 27 cases, to our knowledge, have been reported in the literature. Often, the first observation is of uncontrollable convulsions. The metabolic alterations are often striking and the treatment has mainly been supportive, with the judicious use of pyridoxine hydrochloride in those cases in which a history of ingestion of isoniazid is obtained. The response to the administration of pyridoxine has been difficult to evaluate.

Adolescent↗
PubMed1980

Maintenance of some ColE1-type plasmids in chemostat culture.

When cells carrying the plasmids RP1, pDS4101 (a ColK derivative) or pDS1109 (a ColE1 derivative) were maintained in chemostat culture in the absence of antibiotic selection, plasmid-free segregants were not detected after 120 generations of nutrient-limited growth. By contrast, plasmid-free segregants of pMB9- and pBR322-containing cells arose after approximately 30 generations, irrespective of the host genetic background. However, even though pDS1109 was maintained its copy-number fell five-fold during 80 generations of limited growth. It is suggested that loss of pBR322 occurs following a similar copy-number decrease which results in defective segregation of the plasmid to daughter host cells. This defective segregation was not complemented in trans by either RP1 or pDS4101.

Cell Division↗