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Biomedical subjects

M Harrison

Publications and source records attributed to M Harrison.

At least 235 records · Page 13Linked to original sources
PubMed1981

Hemoglobin switching in sheep. Isolation of the fetal gamma-globin gene and demonstration that the fetal gamma- and adult beta A-globin genes lie within eight kilobase segments of homologous DNA.

A recombinant DNA library of sheep genomic DNA fragments inserted into the bacteriophage vector, Charon 4A, was screened by plaque hybridization with a probe for sheep gamma-globin gene sequences. Three clones containing overlapping segments of DNA, the total length of which was 25 kb, were identified; each included all or a part of the same globin gene. Nucleotide sequencing of substantial portions of the globin gene in one clone, lambda S gamma G31, and of the gene in a previously isolated recombinant, lambda S beta AG21, established that the genes in these recombinants encoded for the gamma- and beta A-globin genes of sheep, respectively. Features characteristic of globin genes in other species that were identified in both genes included a sequence, ATAAAA, 30 nucleotides from the presumed site of initiation of transcription, a region of "capping homology," two introns at positions corresponding to amino acids 29-30 and 103-104 and the polyadenylation sequence, AATAAA, in the 3' untranslated region. Electron microscopic analysis of heteroduplexes formed between lambda S gamma G31 and lambda S beta AG21 revealed that the gamma and beta A genes of sheep lie within segments of homologous DNA at least 8 kb in length within which were identified small regions of nonhomology both 5' and 3' to the genes.

Amino Acid Sequence↗
PubMed1980

A family of long reiterated DNA sequences, one copy of which is next to the human beta globin gene.

An unusually long repeated DNA sequence was identified in cloned DNA, three kb 3' to the human beta-globin gene. Other members of this repeated sequence family were isolated from a human genomic DNA library and characterized by Southern blotting techniques, electron microscopy, and solution hybridization. The copy located next to the beta-globin gene was found to be 6.4 +/- 0.2 kb long and continuous over that length. This repeated sequence family comprises about 1% of the human genome and contains 3000-4800 copies of moderate sequence divergence which are interspersed with other less-highly repeated DNA. The 6.4 kb repeated unit does not appear to be composed of any smaller tandemly repeated subunits, nor is it expressed at a high level in bone marrow cell RNA.

Bacteriophage lambda↗
PubMed1978

Demonstration of the outer surface of freeze-etched normal human platelets: correlation with buoyant density.

The external surface of the normal human platelet shows clusters of spherical particles in a reticular pattern with smooth and regular surface membrane in adjacent areas. Labelling with cationic ferritin demonstrates a diffuse distribution of ferritin particles which stop at the fracture face of the intramembranous surface. The intramembranous surface is not labelled. Previously discrepant observations on the plasma membrane surface are probably due to different techniques of platelet preparation for freeze-etch electron microscopy. Density-dependent platelet sub-populations do not differ with respect to the ultrastructural features of their external surface and intramembranous portions of the plasma membrane. Based upon the relationship between platelet density and age, it appears that the ultrastructure of the normal platelet plasma membrane does not change with in vivo ageing.

Blood Platelets↗
PubMed1978

Cows' milk-sensitive enteropathy.

Serial small intestinal biopsies related to withdrawal and challenge with cows' milk are described in 5 infants with cows' milk protein intolerenace. On the basis of these serial observations the existence of a cows' milk-sensitive enteropathy in infancy is clearly established. The cows' milk-sensitive mucosal lesion varied in its severity ranging from a partly flat mucosa to a mild degree of partial villous atrophy. Intraepithelial lymphocyte counts rose after a positive milk challenge, but on only one occasion to a level outside the normal range. The technique of serial biopsies related to dietary milk enables a firm diagnosis of cows' milk intolerance to be made upon the basis of a single milk challenge. Clinically this appears to be a temporary condition which disappears by the age of 2 years.

Animals↗
PubMed1977

Reinvestigation of lactose intolerant children: lack of correlation between continuing lactose intolerance and small intestinal morphology, disaccharidase activity, and lactose tolerance tests.

Thirty children on a lactose-free diet aged from 2-38 months who had previously been diagnosed as having secondary lactose intolerance were reinvestigated on 32 occasions by an oral lactose tolerance test, small intestinal biopsy, and measurement of disaccharidase activity in order to detect the presence of continuing lactose intolerance before reintroduction of milk. No correlation was found between continuing lactose intolerance, as diagnosed by the development of watery stools containing excess reducing substances after an oral load of lactose, and maximum blood glucose rise during a lactose tolerance test, lactase levels, and small intestinal morphology.

Child, Preschool↗
PubMed1977

Value of exchangeable electrolyte measurement in the treatment of myasthenia gravis.

We have investigated electrolyte exchange in myasthenia gravis before and after corticotrophin therapy, using a four-isotope dilution technique. Clinical deterioration in patients on corticotrophin is associated with a fall of more than 20% in the intracellular potassium concentration, suggesting that all myasthenics so treated should be given potassium supplementation.

Adrenocorticotropic Hormone↗
PubMed1977

Regional intra-arterial infusion of adriamycin in the treatment of cancer.

Forty patients with otherwise untreatable advanced carcinomas received arterial infusions of adriamycin. Significant responses were seen in five of nine tumors of the bladder, two of five hypernephromas, two of two islet cell tumors, three of five sarcomas and one of two metastatic tumors of the breast. One patient with advanced transitional cell carcinoma of the bladder had no tumor at the time of a subsequent resection. There were no responses seen in two oat cell tumors metastatic to the liver, one seminoma of the retroperitoneal space metastatic to the liver, one squamous cell tumor metastatic to the liver, one squamous cell of the vulva, one carcinoma of the cervix uteri and one cloacogenic carcinoma. these responses in advanced tumors are exciting. The use of this technique to reduce tumor bulk prior to operation, irradiation, adjuvant chemotherapy and immunotherapy may allow a significant breakthrough for such tumors as sarcomas, hypernephromas and transitional cell carcinomas of the bladder. Further studies will be pursued using this concept.

Adenocarcinoma↗
PubMed1977

Brief reports influence of "mentally retarded" label on teachers' nonverbal behavior toward preschool children.

Teachers (N = 12) were assigned to either an experimental (labeled) or control (nonlabeled) child. All children were, in fact, nonhandicapped and had no diagnosis or record of mental retardation. After reading a description (labeled or nonlabeled) of their child's developmental status, each teacher read their child a story. The results indicated that teachers were more immediate (i.e., showed less social distance) to children bearing the "mentally retarded" label. Implications of this finding were discussed.

Behavior↗