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Biomedical subjects

D C Watson

Publications and source records attributed to D C Watson.

At least 109 records · Page 6Linked to original sources
PubMed1979

The complete amino-acid sequence of a trout-testis non-histone protein, H6, localized in a subset of nucleosomes and its similarity to calf-thymus non-histone proteins HMG-14 and HMG-17.

The complete amino acid sequence of a basic non-histone protein, H6, isolated from the chromatin of rainbow trout (Salmo gairdnerii) testis cells, has been determined. Protein H6, first described by D. T. Wigle and G. H. Dixon [J. Biol. Chem. 246, 5636--5644 (1971)] was extracted with 5% trichloracetic acid and purified by ion-exchange chromatography on carboxymethyl-cellulose (CM-52). Sequence analysis was performed by automatic Edman degradation of the amino terminus of the intact protein and a series of large fragments derived by cleavage with chymotrypsin, staphylococcal protease and with mild acid to cleave at aspartic acid residues. Protein H6 possesses 69 residues and shows considerable similarities to the 89-residue calf thymus HMG-17 protein previously sequenced [Walker, J. M., Hastings, J. R. B. & Johns, E. W. (1977) Eur. J. Biochem. 76, 461--468]. B. Levy W. and G. H. Dixon [Proc. Natl Acad. Sci. U.S.A. 74, 2810--2814 (1977)] have shown that H6 is selectively solubilized when trout testis nuclei (or chromatin) are digested with DNase I under conditions which preferentially hydrolyze that portion of DNA enriched in transcribed sequences [Levy, W. B. & Dixon, G. H. (1977) Nucleic Acids Res. 4, 883--898]. Recently H6 has been located as a stoichiometric component of a distinct subset of trout testis nucleosomes that are complexed with a core nucleosome comprising 140 base pairs of DNA and the inner histones H2A, H2B, H3 and H4 [Levy, W. B., Connor, W. & Dixon, G. H. (1979) J. Biol. Chem., in the press].

Amino Acid Sequence↗
PubMed1979

Primary osteogenic sarcoma of the heart.

The clinical course of a 17-year-old boy with primary osteogenic sarcoma of the left atrium with partial obstruction of the mitral valve and the right pulmonary veins is described. After operative removal of the tumor, echocardiography documented its rapid recurrence. Despite two subsequent open-heart operations and adjuvant chemotherapy and radiotherapy, the patient died twenty-one months after the initial symptoms. Previous reports of such tumors are reviewed, and technical difficulties of removal are discussed.

Adolescent↗
PubMed1979

Multiacetylated forms of H4 are found in a putative transcriptionally competent chromatin fraction from trout testis.

We have examined the distribution of acetylated histones derived from various trout testis chromatin fractions of different composition. Our results indicate that a chromatin fraction, preferentially solubilized by micrococcal nuclease, containing the bulk of the HMG proteins and similar to a fraction released from intact trout nuclei and previously shown to be enriched in transcribed DNA sequences also possesses high levels of multiacetylated species of H4. Histones 2A, 2B and 3 are also acetylated in this particular chromatin fraction. Monoacetylated species of the 4 inner nucleosomal histones appear to be characteristic of the nucleohistone portion of trout testis chromatin.

Acetates↗
PubMed1979

Distant heart procurement for transplantation.

Between January 1, 1977, and September 15, 1978, 39 cardiac transplants were performed on 38 patients. Twenty donor hearts were removed at Stanford University Hospital, and 19 donor hearts were removed at distant hospitals. The characteristics of recipients and donors in both groups were similar. The only significant difference between donor hearts was the mean ischemia time (154 +/- 30 minutes in distant hearts and 52 +/- 12 minutes in local hearts, P less than 0.001). As of February 1, 1979, the total mortality rate was 32% for the distant heart donors and 40% for the local heart donors. No difference between the two groups was present in immediate myocardial function, the need for postoperative inotropic support, the mortality rate within the first 90 days after operation, the mean maximum serum enzyme levels, the occurrence of rejection or infection, and the histological appearance of the hearts, both early and late. The results of cardiac transplantation when hearts are removed at distant hospitals are entirely comparable to the results with hearts removed on site with a minimum ishchemic time. Distant heart procurement provides an expanded donor pool for potential cardiac recipients.

Coronary Vessels↗
PubMed1979

Deconvolution analysis in radionuclide quantitation of left-to-right cardiac shunts.

A poor bolus injection results in an unsatisfactory quantitative radionuclide angiocardiogram in as many as 20% of children with possible, left-to-right (L-R) cardiac shunts. Deconvolution analysis was applied to similar studies in experimental animals to determine whether dependence on the input bolus could be minimized. Repeated good-bolus, prolonged (greater than 2.5 sec), or multiple-peak injections were made in four normal dogs and seven dogs with surgically created atrial septal defects (ASD). QP/QS was determined using the gamma function. The mean QP/QS from ten good-bolus studies in each animal was used as the standard for comparison. In five trials in normal animals, where a prolonged or double-peak bolus led to a shunt calculation (QP/QS greater than 1.2 : 1), deconvolution resulted in QP/QS = 1.0. Deconvolution improved shunt quantitation in eight of ten trials in animals that received a prolonged bolus. The correlation between the reference QP/QS and the QP/QS calculated from uncorrected bad bolus studies was only 0.39 (p greater than 0.20). After deconvolution using a low pass filter, the correlation improved significantly (r = 0.77, p less than 0.01). The technique gave inconsistent results with multiple-peak bolus injections. Deconvolution analysis in these studies is useful in preventing normals from being classified as shunts, and in improving shunt quantitation after a prolonged bolus. Clinical testing of this technique in children with suspected L-R shunts seems warranted.

Angiocardiography↗
PubMed1978

Sites of phosphorylation on pyruvate dehydrogenase from bovine kidney and heart.

The highly purfied pyruvate dehydrogenase complex (EC 1.2.4.1) and uncomplexed pyruvate dehydrogenase from bovine kidney and heart mitochondria were phosphorylated and inactivated with pyruvate dehydrogenase kinase and [gamma-32P]ATP. Tryptic digestion of the phosphorylated pyruvate dehydrogenase yielded three phosphopeptides, a mono- (site 1) and a di- (sites 1 and 2) phosphorylated tetradecapeptide and a monophosphorylated nonapeptide (site 3). The amino acid sequences of the three phosphopeptides were established to be Tyr-His-Gly-His-Ser(P)-Met-Ser-Asn-Pro-Gly-Val-Ser-Tyr-Arg, Tyr-His-Gly-His-Ser(P)-Met-Ser-Asn-Pro-Gly-Val-Ser(P)-Tyr-Arg, and Tyr-Gly-Met-Gly-Thr-Ser(P)-Val-Glu-Arg. Phosphorylation proceeded markedly faster at site 1 than at sites 2 and 3, and phosphorylation at site 1 correlated closely with inactivation of pyruvate dehydrogenase. Complete inactivation of pyruvate dehydrogenase was associated with incorporation at site 1 of 1.0--1.6 mol of phosphoryl groups per mol of enzyme. Since pyruvate dehydrogenase is a tetramer (alpha2beta2) and since phosphorylation occurs only on the alpha subunit, the possibility of half-site reactivity is considered.

Adenosine Triphosphate↗
PubMed1978

Salmonella pollution of surface waters.

Surface waters in 14 selected sites were examined for the presence of salmonella using modified Moore's swabs. The sites included an upland impounding reservoir, 3 rivers and 10 streams within Lancashire and Cheshire, selected because of their accessibility to farm livestock. Salmonellas were isolated from 22 out of the 57 swabs examined representing 10 sites. The probable source of pollution was shown to be sewage or farm effluent and an examination of sites over a wider area may be expected to produce similar results. The significance of these findings is discussed in relation to the epidemiology of salmonella infections and the possible disinfection of effluent discharges.

England↗
PubMed1977

The purification, characterization and partial sequence determination of a trout testis non-histone protein, HMG-T.

A specific non-histone chromatin-associated protein, having a high content of both acidic and basic amino acids has been isolated from the chromatin of rainbow trout (Salmo gairdnerii) testis cells. The protein has been prepared by the extraction of chromatin with 0.35 M sodium chloride and purified by chromatography on carboxymethyl-cellulose with a gradient of lithium chloride at pH 9.0. The amino acid sequence of the first 29 residues of the amino-terminal region has been determined using an automatic protein sequencer. The primary structure of this protein differs from that of any of the histones yet sequenced and, therefore, cannot be a degradation produce of any of them. Moreover, the N-terminal amino acid sequence shows considerable similarity to the HMG-1 and HMG-2 chromosomal proteins described by Goodwin et al. [Eur. J. Biochem. 38, 14-19 (1973)] whose-N-terminal sequences were also determined in this laboratory.

Amino Acid Sequence↗
PubMed1977

The substrate specificity of adenosine 3':5'-cyclic monophosphate-dependent protein kinase of rabbit skeletal muscle.

The known amino acid sequences at the two sites on phosphorylase kinase that are phosphorylated by cyclic AMP-dependent protein kinase were extended. The sequences of 42 amino acids around the phosphorylation site on the alpha-subunit and of 14 amino acids around the phosphorylation site on the beta-subunit were shown to be: alpha-subunit Phe-Arg-Arg-Leu-Ser(P)-Ile-Ser-Thr-Glu-Ser-Glx-Pro-Asx-Gly-Gly-His-Ser-Leu-Gly-Ala-Asp-Leu-Met-Ser-Pro-Ser-Phe-Leu-Ser-Pro-Gly-Thr-Ser-Val-Phe(Ser,Pro,Gly)His-Thr-Ser-Lys; beta-subunit, Ala-Arg-Thr-Lys-Arg-Ser-Gly-Ser(P)-VALIle-Tyr-Glu-Pro-Leu-Lys. The sites on histone H2B which are phosphorylated by cyclic AMP-dependent protein kinase in vitro were identified as serine-36 and serine-32. The amino acid sequence in this region is: Lys-Lys-Arg-Lys-Arg-Ser32(P)-Arg-Lys-Glu-Ser36(P)-Tyr-Ser-Val-Tyr-Val- [Iwai, K., Ishikawa, K. & Hayashi, H. (1970) Nature (London) 226, 1056-1058]. Serine-36 was phosphorylated at 50% of the rate at which the beta-subunit of phosphorylase kinase was phosphorylated, and it was phosphorylated 6-7-fold more rapidly than was serine-32. The amino acid sequences when compared with those at the phosphorylation sites of other physiological substrates suggest that the presence of two adjacent basic amino acids on the N-terminal side of the susceptible serine residue may be critical for specific substrate recognition in vivo.

Amino Acid Sequence↗
PubMed1977

Effects of operation on left atrial size and the occurence of atrial fibrillation in patients with hypertrophic subaortic stenosis.

The relation between left atrial size and atrial fibrillation was examined in 37 patients who had left ventriculomyotomy and myectomy at the National Heart and Lung Institute. Atrial fibrillation was present in 11 of 27 (41%) patients with an echocardiographically measured left atrial dimension greater than 45 mm. No patient with a left atrial dimension less than 45 mm had atrial fibrillation pre or postoperatively. Eleven of 13 patients less than 40 years of age with an abnormal preoperative left atrial dimension had a 10% or greater reduction in left atrial dimension postoperatively. A group of 21 patients 40 years of age or older had an abnormal left atrial dimension preoperatively, and no significant change postoperatively. These results indicate that left ventriculomyotomy and myectomy can produce a significant decrease in left atrial size in younger patients with idiopathic hypertrophic subaortic stenosis. It is hoped that the decrease in atrial size may reduce the risk of atrial fibrillation in these patients.

Adult↗
PubMed1977

Morphology of canine hearts after 24 hours' preservation and orthotopic transplantation.

Ten dogs underwent orthotopic cardiac transplantation after preservation of the donor heart for 24 hours in an oxygenated hypothermic, hypertonic, intracellular solution, either with (five dogs) or without (five dogs) continuous, oxygenated, low-pressure perfusion. Eight dogs survived for 24 hours after transplantation, at which time they were put to death. The two nonsurvivors were among the five with nonperfused hearts. Examination of all 10 donor hearts showed differences between the two groups: Four of five nonperfused hearts showed severe transmural myocardial coagulation necrosis but only small foci of contraction band necrosis (myofibrillar degeneration). The perfused hearts, however, showed more extensive subendocardial areas of contraction-band necrosis, but only minimal and focal coagulation necrosis, indicating less severe hypoxic damage. These results indicate that oxygenated perfusion with a hypothermic, hypertonic, intracellular solution may permit improved transplant survival after extended cardiac preservation.

Animals↗
PubMed1977

Heart and liver transplantation. Consistent survival after prolonged donor heart preservation.

Twelve dogs underwent orthotopic cardiac transplantation after donor heart preservation for 24 hr in a hypothermic hypertonic intracellular solution. Donors were divided into two groups: continuous oxygenated perfusion and nonperfusion. After 24 hr, transplantation was performed. All six perfused and four nonperfused donors hearts survived a 24-hr postoperative period. Survivors had normal cardiac output, right and left atrial pressures, and aortic pressures. After transplantation, all perfused hearts demonstrated mild left ventricular damage while nonperfused hearts had severe damage. Hypothermic hypertonic intracellular perfusion may allow improved protection for short-term myocardial preservation and survival after extended myocardial preservation.

Animals↗