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Biomedical subjects

D Putnam

Publications and source records attributed to D Putnam.

27 records · Page 2Linked to original sources
PubMed1990

Differential regulation of Na,K-ATPase alpha 1, alpha 2, and beta subunit mRNA and protein levels by thyroid hormone.

The purpose of this study was to determine the effect of thyroid status on the Na,K-ATPase alpha isoforms and beta in rat heart, skeletal muscle, kidney, and brain at the levels of mRNA, protein abundance, and enzymatic activity. Northern and dot-blot analysis of RNA (euthyroid, hypothyroid, and triiodothyronine-injected hypothyroids = hyperthyroids) and immunoblot analysis of protein (euthyroid and hypothyroid) revealed isoform-specific regulation of Na,K-ATPase by thyroid status in kidney, heart, and skeletal muscle and no regulation of sodium pump subunit levels in the brain. In general, in the transition from euthyroid to hypothyroid alpha 1 mRNA and protein levels are unchanged in kidney and skeletal muscle and slightly decreased in heart, while alpha 2 mRNA and protein are decreased significantly in heart and skeletal muscle. In hypothyroid heart and skeletal muscle, the decrease in alpha 2 protein levels was much greater than the decrease in alpha 2 mRNA levels relative to euthyroid indicating translational or post-translational regulation of alpha 2 protein abundance by triiodothyronine status in these tissues. The regulation of beta subunit by thyroid status is tissue-dependent. In hypothyroid kidney beta mRNA levels do not change, but immunodetectable beta protein levels decrease relative to euthyroid, and the decrease parallels the decrease in Na,K-ATPase activity. In hypothyroid heart and skeletal muscle beta mRNA levels decrease; beta protein decreases in heart and was not detected in the skeletal muscle. These findings demonstrate that the euthyroid levels of expression of alpha 1 in heart, alpha 2 in heart and skeletal muscle, and beta in kidney, heart, and skeletal muscle are dependent on the presence of thyroid hormone.

Animals↗
PubMed1990

The effect of inpatient psychiatric hospitalization on weight gain in children and adolescents.

Measures of weight were obtained both at admission and at discharge for children and adolescents receiving inpatient services at a private psychiatric hospital. The sample included 20 males and 20 females from each of three units: child psychiatric, adolescent psychiatric, and adolescent substance abuse. The difference between the actual weight change of the subjects and the weight change predicted from growth charts was obtained. Overall, subjects gained a significant amount of weight. The actual mean increase in weight was roughly 3.5 times greater than the predicted increase, and there were no significant differences in weight gain between males and females among patients from each of the three units. Potential explanations for this increase in weight are explored, and the implications are discussed.

Adolescent↗
PubMed1983

Fluid resuscitation in circulatory shock: a comparison of the cardiorespiratory effects of albumin, hetastarch, and saline solutions in patients with hypovolemic and septic shock.

Twenty-six consecutive patients in hypovolemic shock were randomized to fluid challenge with 5% albumin (A), 6% hetastarch (H), or 0.9% saline (S) solutions. Fluid challenge consisted of 250 ml of test fluid every 15 min until the pulmonary artery wedge pressure (WP) reached 15 mm Hg. Thereafter, WP was maintained at 15 mm Hg for an additional 24 h with infusions of the same test fluid. Vital signs, hemodynamic and respiratory variables, as well as arterial lactate and colloid osmotic pressure (COP) were monitored according to protocol. Chest x-rays were performed by standardized technique before fluid challenge and at 12 and 24 h of maintenance fluid therapy and were evaluated for evidence of pulmonary edema. Cardiac function and hemodynamic stability were restored by fluid challenge with A, H, and S. Two to 4 times the volume of S as A or H was required to achieve similar hemodynamic endpoints. COP was increased by fluid challenge with A or H but was markedly reduced by fluid challenge with S and throughout the 24-h maintenance period. Fluid challenge resulted in reductions in COP-WP gradient of 62% in the A, 43% in the H, and 125% in the S groups. Resuscitation with S resulted in a significantly higher incidence of pulmonary edema (87.5%) than did resuscitation with A (22%) or H (22%). Urine output was not different among the groups at any time during the study. We conclude that 6% H performs as well as 5% A as a resuscitative fluid and that resuscitation with either of these colloids is associated with a lower incidence of pulmonary edema than is resuscitation with 0.9% S.

Aged↗
PubMed1976

Sequences related to immunoglobulin kappa chain messenger RNA in T cells.

We investigated by molecular hybridization whether T cells contain RNA sequences homologous to RNA which codes for immunoglobulin kappa-chain (k-chain). A radioactive probe of complementary DNA (cDNA) was prepared by transcription of purified k-chain mRNA from mouse myeloma MOPC-41 with reverse transcriptase (RNA-dependent-DNA nucleotidyltransferase) from avian myeloblastosis virus. The cDNA probably corresponded only to the constant region and 3'-terminus of k-chain mRNA. Kappa-chain cDNA was found to hybridize efficiently with RNA from both thymus cells and an established culture of thymoma cells. The thymus and thymoma cells contained 99.8% and 100% theta-positive cells, respectively. Quantitatively the average thymus T cell (thymus derived lymphocyte) contained about one half as much k-chain mRNA as the average spleen B cell ("bursa" dependent lymphocyte), whereas the thymoma cells contained only 1/33 as much. Control hybridizations of k-chain cDNA with myeloma and liver RNA support the conclusion that T cells in the thymus and in the thymoma cell line synthesize k-chain mRNA-like molecules. The thermal stability of hybrids of k-chain cDNA with RNA from spleen, thymus, thymoma, and another k-chain producing myeloma tumor was lower than that with MOPC-41 RNA. This finding may be due to the existence of several slightly different ck genes in the mouse as suggested by various control experiments.

B-Lymphocytes↗
PubMedDate not supplied

Enantioselective release of 5-fluorouracil from N-(2-hydroxypropyl)methacrylamide-based copolymers via lysosomal enzymes.

Water soluble copolymers based on N-(2-hydroxypropyl)methacrylamide (HPMA) containing oligopeptide side chains terminated in an alpha-substituted glycine derivative of the anticancer compound 5-fluorouracil (5-FU) were synthesized by a new facilitated synthetic route and studied for their ability to release free 5-FU in the presence of lysosomal enzyme preparations. In addition, the properties of the low molecular weight alpha-substituted glycine derivatives were studied in the presence of lysosomal enzyme preparations and leucine aminopeptidase. The results revealed that (1) the stereochemistry (L vs D) of the alpha-substituted glycine derivative, (2) the hydrophobicity (Ala vs Leu) of the penultimate amino acid residue relative to the alpha-substituted glycine derivative, and (3) the total length of the oligopeptide sequence spacer (tetrapeptide vs hexapeptide) terminated in the alpha-substituted glycine derivative and the polymer carrier all directly influence the enzymatically catalyzed release of free 5-FU.

Amino Acid Sequence↗