Biomedical subjects

E M Davis

Publications and source records attributed to E M Davis.

At least 55 records · Page 3Linked to original sources

PubMed1986

Clinical and cytogenetic correlations in 63 patients with therapy-related myelodysplastic syndromes and acute nonlymphocytic leukemia: further evidence for characteristic abnormalities of chromosomes no. 5 and 7.

Clinical, histologic, and cytogenetic features in 63 patients with a therapy-related myelodysplastic syndrome (t-MDS) or acute nonlymphocytic leukemia (t-ANLL) following cytotoxic chemotherapy or radiotherapy for a previous disease were analyzed. Eleven patients had received only radiotherapy for the primary disorder. In most cases, high doses had been administered to treatment ports that included the pelvic or spinal bone marrow. Twenty-one patients had received only chemotherapy for their primary disease, all for more than 1 year and all but one with an alkylating agent, either alone or in combination with other drugs. Thirty-one patients had received both radiotherapy and chemotherapy, either concurrently or sequentially. A clonal chromosomal abnormality was observed in marrow or blood cells from 61 of the 63 patients (97%). Fifty-five patients (87%) had a clonal abnormality of chromosomes no. 5 and/or 7 consisting of loss of all or part of the long arm of the chromosome. The critical chromosome region that was consistently deleted in all 17 patients with del(5q) comprised bands q23 to q32. In addition to nos. 5 and 7, five other chromosomes (no. 1, 4, 12, 14, and 18) were found to be nonrandomly involved. Both t-MDS and t-ANLL are late complications of cytotoxic therapies that have distinctive clinical and histologic features and are associated with characteristic aberrations of chromosomes no. 5 and 7. It seems likely that these two chromosomes contain genes involved in the pathogenesis of these hematopoietic neoplasms.

Acute Disease↗

PubMed1984

Twenty-four hour pharmacy service in hospitals with less than 300 beds--Part 8.

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Hospital Bed Capacity, 100 to 299↗

PubMed1981

Urinary 3-methylhistidine/creatinine ratio as a clinical tool: correlation between 3-methylhistidine excretion and metabolic and clinical states in healthy and stressed premature infants.

We have investigated the role of the urinary 3-methylhistidine (3MH) excretion, a measure of protein catabolism, in the evaluation of the metabolic state of premature infants. Two-hundred and twenty-two 24 hr urine collections and 3MH/Cr ratio determinations (expressed as mumoles of 3MH per mg creatinine) were carried out in 36 infants (average gestational age 32.7 +/- 0.7 wk, weight 1640 +/- 120 grams) and the relationship between the 3MH/Cr ratios and the metabolic and clinical state has been investigated. Five or more 3MH/Cr measurements were carried out on each of 19 infants and serial determinations on four of those babies are presented. The urinary 3MH/Cr ratio of healthy infants with adequate caloric intake and normal growth curve was .148 +/- .039 (S.D.) mumol/mg, about 35% higher than the 3MH/Cr ratio in healthy adults. As long as the premature infants were healthy the degree of prematurity had no effect on the 3MH/Cr ratio. The relationship between 3MH/Cr ratio and nitrogen balance was highly significant (p less than .001). 3MH/Cr ratio also correlates very well with the metabolic status of the infants: in the group with normal 3MH/Cr ratios less than or equal to .175 (.148 + 1 S.D., n = 90) there were four clinically stressed infants (4.4% false negative rate) while in the group with elevated 3MH/Cr ratios greater than .225 (.148 + 2 S.D.; n = 79) there were only three clinically well infants (3.8% false positive rate). In comparing the clinical status and 3MH/Cr ratios, we found that in the group of infants who could not be clearly defined as clinically well or stressed (n = 108) the 3MH/Cr ratio was more useful than clinical judgment in the prediction of metabolic status. It can be concluded that 3MH/Cr ratio is a potentially useful clinical tool which describes with high accuracy the clinical and metabolic status of premature infants. This conclusion is further supported by the data of serial 3MH/Cr determinations.

Birth Weight↗

PubMed1981

Significance of cell-to cell contacts for the directional movement of neural crest cells within a hydrated collagen lattice.

Neural tubes whose neural crest had just begun migration were isolated from stage-14 chick embryos, cleaned with 0.1% trypsin, and cultured in transparent hydrated collagen lattices (HCL) in an effect to stimulate in part the three-dimensional environment through which neural crest cells migrate in situ, in the embryo. The concentration of collagen in the lattices varied from 50 microgram/ml to 390 microgram/ml. The mode of movement and contact behaviour of neural crest cells migrating from the neural tube under these conditions were recorded directly with time-lapse cinemicrography. Both their shape and their rate of translocation were dependent on the concentration of collagen in the HCL. In low concentrations (50 microgram/ml to 105 microgram/ml), neural crest cells have elongate spindle shapes and translocate at an average rate of 1 micrometer/min, whereas in high concentrations (190 microgram/ml to 390 microgram/ml), their shape is rounded, and they translocate at an average rate of only 0-5 micrometer/min. Neural crest cells migrate from neural tubes in these preparations principally in loose clusters, with a few single cells in the lead. The cells in these groups display leading-to-trailing edge adhesions and form tongues or streams of cells directed away from the neural tube. The paths of migration of both individual cells and groups of cells are aligned with the collagen fibrils of the HCL, which radiate from the neural tube. The classical visible characteristic of contact inhibition of movement, change in direction of cell movement after contact with other cells, was not observed; neither the rate of translocation nor the time spent migrating away from the tube is dependent on the number of contacts between cells. It is concluded that the directional movement of neural crest cells in HCL cultures does not depend on contact inhibition of movement.

Animals↗

PubMed1980

Urinary 3-methylhistidine excretion and nitrogen balance in healthy and stressed premature infants.

Conventional methods of assessing adequate nutrition in children may be inaccurate or change too slowly to be helpful during acute illness. Techniques to measure protein synthesis or breakdown provide more accurate information. Three-methylhistidine (3MH), an unusual amino acid found in actin and myosin, is not further metabolized and is quantitatively excreted following muscle degradation. Urinary excretion of 3MH has, therefore, been proposed as a marker of protein catabolism. The ratio of 3MH to creatinine in 24-hr urine collectons was studied in 14 healthy or stressed premature infants, and compared to nitrogen balance (N bal), caloric intake and clinical course. There is a significant inverse correlation between 3MH/Cr ratio and N Bal (R = -.507). The mean 3MH/Cr ratio was 0.140 +/- 0.037 mu mole/mg (n = 37) in healthy growing premature infants and 0.296 +/- 0.160 (n = 26) in infants who were stressed and/or had inadequate nutrient intake. Healthy growing infants almost invariably had a ratio below 0.200. Serial determinations in three infants consistently showed a rise in the ratio to above 0.200 during periods of stress or decreased intake. The 3MH/Cr ratio may be a more sensitive indicator of metabolic status and may be useful clinically, especially in infants receiving total parenteral nutrition.

Creatinine↗

PubMed1980

Translocation of neural crest cells within a hydrated collagen lattice.

Chick neural tubes were cultured either on planar substrata of collagen-coated Falcon plastic in growth medium with serum or within a hydrated collagen lattice (HCL) in growth medium either with or without serum. Using time-lapse cinemicrography, neural crest cells were observed emigrating from neural tubes over the collagen substrata. Once separated from the neural tube, they seldom reunite with it. Though the average rate at which the neural crest cells translocate was the same in the different culture conditions, approximately 1.0 micron/min, distinct differences in morphology and mode of translocation were observed. Neural crest cells on collagen-coated culture dishes have a flattened fibroblastic morphology and mode of translocation; in an HCl with serum, they have a bipolar shape and translocate by advancing a long, narrow leading protrusion and by periodically retracting the attenuated trailing portion of the cell; and in a serum-free HCL, they have a unipolar shape and translocate by advancing a long, narrow, branched leading protrusion and by periodically transferring the cytoplasm of the large, rounded trailing cell body forward, past a bulbous structure, and into the leading protrusion.

Animals↗

PubMed1979