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Biomedical subjects

D C Watson

Publications and source records attributed to D C Watson.

At least 91 records · Page 5Linked to original sources
PubMed1985

A note on the use of Rappaport-Vassiliadis medium (R10/RV) for the isolation of salmonellas from sewage and sewage sludges.

The use of a modified Rappaport broth for the selective enrichment of salmonellas in sewage sludge is described. Comparative trials were carried out using Muller Kauffman--Tetrathionate (MKT) broth and Rappaport-Vassiliadis (R10/RV) medium for selective enrichment. Results have indicated that R10/RV broth is more selective and is to be preferred for routine monitoring.

Culture Media↗
PubMed1984

Structural differences between two lectins from Cytisus scoparius, both specific for D-galactose and N-acetyl-D-galactosamine.

Three lectin fractions were obtained from seeds of the leguminous plant Cytisus scoparius (Scotch broom) by means of affinity chromatography on a N-acetyl-D-galactosamine medium. The first fraction, termed CSIa, was equally well inhibited in haemagglutination experiments by D-galactose and by N-acetyl-D-galactosamine and consisted of a group of isolectins formed from closely related polypeptide chains of approx. Mr 30000. The second fraction, CSIb, was closely related to CSIa in specificity, c.d. and other properties. The third fraction contained a homogeneous lectin, CSII, formed from subunits again of approx. Mr 30000. CSII was 100 times more readily inhibited by N-acetyl-D-galactosamine than by D-galactose. Despite the similarity in specificity, comparative studies of their amino acid composition, c.d. and N-terminal amino acid sequence showed that the CSIa and CSII lectins diverged considerably in structure. The lectin from Cytisus sessilifolius, specific for chitobiose, was also examined and resembled CSIa in composition and c.d. properties.

Acetylgalactosamine↗
PubMed1984

Surgical approach to corrected transposition of the great vessels and situs inversus [I, D, D] with ventricular septal defect and systemic atrioventricular valve regurgitation.

Successful surgical repair of a 4-year-old boy with situs inversus [I, D, D] and corrected transposition of the great vessels (TGV) as well as hemodynamically significant ventricular septal defect (VSD), systemic atrioventricular (tricuspid) valve regurgitation, and atrial septal defect is described. Unique technical aspects of VSD and tricuspid valve repair in association with corrected TGV and situs solitus or inversus are discussed and clarified.

Child, Preschool↗
PubMed1984

Repair of anomalous origin of the left coronary artery in the infant and small child.

Anomalous origin of the left coronary artery from the pulmonary artery is associated with myocardial infarction, left ventricular dysfunction, mitral valve dysfunction and, occasionally, intracardiac congenital abnormalities. A technique that utilizes a flap of the anterior wall of the pulmonary artery to serve as a neocoronary artery to direct aortic flow from a created aortopulmonary window to the pulmonary artery orifice of the anomalous left coronary artery was used in five patients aged 2.5 months to 4.75 years. Two patients were less than 4 months of age at operation. There was one death 2 days after operation and one late death. The two youngest patients required mitral valve replacement. Two of the three surviving patients are well at follow-up at 7 to 44 months. One patient has been lost to follow-up study. One patient had postoperative catheterization which showed an intact repair. The pulmonary artery neocoronary procedure is applicable to infants and small patients with anomalous origin of the left coronary artery from the pulmonary artery.

Child, Preschool↗
PubMed1983

The complete amino acid sequence of oncomodulin--a parvalbumin-like calcium-binding protein from Morris hepatoma 5123tc.

Oncomodulin is an acidic calcium-binding protein of 108 amino acids which has been detected only in tumors. The complete amino acid sequence of rat oncomodulin has been established, and the N-terminus shown to be N-acetylserine. Homology of the oncomodulin sequence with members of the troponin C superfamily of calcium-binding proteins was demonstrated, and putative calcium-binding domains were located. A further degree of homology was established between oncomodulin and the parvalbumins, including rat parvalbumin. Oncomodulin was therefore considered to be a parvalbumin-like calcium-binding protein.

Amino Acid Sequence↗
PubMed1983

A new member of the troponin C superfamily: comparison of the primary structures of rat oncomodulin and rat parvalbumin.

When the amino-acid sequence of the 108-residue, rat tumour calcium-binding protein, oncomodulin, was aligned with that of rat muscle parvalbumin, 55 homologous positions were found, with an additional 33 single base-pair substitutions. This extensive homology, with virtual identity of the calcium-binding domains, signalled oncomodulin to be a member of the troponin C superfamily. The presence of Cys-18 and Phe-66 in oncomodulin, plus its isoelectric point of 3.9, suggest that this tumour protein is a beta-parvalbumin, rather than a muscle alpha-parvalbumin.

Amino Acid Sequence↗
PubMed1983

Advantages of a new polyvinyl chloride double-lumen tube in thoracic surgery.

Double-lumen endobronchial tubes offer many advantages during thoracic operations. However, technical problems with tube placement and potentially life-threatening complications have discouraged widespread use of standard double-lumen tubes. Some of these problems may be reduced with a new polyvinyl chloride (PVC) double-lumen tube. A total of 214 intubations were undertaken in 204 patients using one of three endobronchial tubes. The cases of these patients were reviewed to determine differences in the complications associated with the Carlens, Robertshaw, and PVC tubes. Complications included unsuccessful or difficult intubation, tube dislodgment, unsatisfactory lung deflation, tube malposition, and hypoxemia. In 8 of 16 intubations with the Carlens tube and in 14 of 62 intubations with the Robertshaw tube, there were complications. In all, 22 of 78 intubations (28%) using conventional double-lumen tubes were complicated compared with 5 of 136 (4%) using the PVC tube. The technical problems and risks of endobronchial intubation were reduced significantly with the PVC double-lumen tube.

Adolescent↗
PubMed1982

Early failures of Ionescu-Shiley bioprosthesis after mitral valve replacement in children.

Two infants, 101/2 and 11 1/2 months of age, underwent mitral valve replacement with Ionescu-Shiley bovine bioprosthesis for congenital cardiac defects. Both patients had early valve failure, 19 months and 4 months after implantation, due to the growth of excessive collagen on the ventricular surface of the bioprosthesis with adherence of the collagen primarily to the sewing rings and struts of the valves. The cause of this excessive collagen reaction is unknown. Further study is needed to document the true incidence of this problem.

Bioprosthesis↗
PubMed1981

Molecular analysis of the protamine multi-gene family in rainbow trout testis.

We have synthesized a family of double-stranded cDNAs (ds cDNAs) using as a template the family of highly purified protamine mRNAs from rainbow trout testis. Individual pure protamine cDNA components were isolated by cloning this family of protamine ds cDNAs in a plasmid vector (pMB9). Clones containing protamine sequences were characterized by restriction mapping and by a positive hybrid-selected translation assay, which allowed us to correlate particular cDNAs with particular protein components. To allow more detailed comparisons, complete nucleotide sequences were determined for selected protamine clones. We have detected at least 5 distinctly different coding sequences, which nevertheless show at least 82% homology, and which have probably arisen by repeated gene duplication. These very highly conserved coding sequences do however contain a distinctly variable region near the 5'-end of the mRNA (N-terminus of the protein), corresponding to the major sites of serine phosphorylation. Since the amino acid sequences predicted by our DNA sequences were slightly different from those previously published (1), we have independently determined the amino acid sequences of protamine components CI, CII, CIII from our own source of trout testis. These new peptide sequences are completely consistent with those predicted by our nucleotide sequences. The 3'-untranslated regions of the protamine mRNAs are, surprisingly almost as highly conserved as the coding regions. Both coding and 3'-noncoding portions appear to be under a similar degree of selective pressure and evolutionary constraint to remain constant.

Animals↗
PubMed1981

Amino acid sequence homologies between the high-mobility-group proteins, HMG-T from trout testis and HMG-1 and -2 from calf thymus: is the poly-aspartic-glutamic acid polypeptide within the main chain?

The amino acid sequence of the N-terminal two-thirds of a trout high-mobility-group protein, HMG-T, has been determined as a continuous sequence of 174 residues out of a total for the whole molecule of 260 residues. When this sequence was compared with published sequences of long cyanogen bromide-derived peptides from the analogous calf-thymus proteins, HMG-1 and -2 (Walker et al., 1979), there was strong homology, with 60-70% identity of corresponding amino acid residues in the three proteins, the majority in lengthy identical runs. However, a discrepancy in the position of a highly acidic run of aspartic and glutamic residues suggests this region may not lie within the main polypeptide chain but may represent a separate chain or possibly a branched structure.

Amino Acid Sequence↗
PubMed1981

Translocation of the aortic valve for prosthetic valve endocarditis.

Aortic prosthetic valve endocarditis is frequently associated with a perivalvular ring abscess which destroys the normal annulus, so that it is difficult to seat a new prosthesis. Between November, 1974, and January, 1980, we treated four patients with aortic prosthetic endocarditis by translocation of the aortic valve, closure of the native coronary artery ostia, and placement of saphenous vein bypass grafts to the coronary arteries. In each case operation was undertaken because of progressive congestive heart failure resulting from aortic regurgitation; two patients had systemic emboli, and two patients had uncontrolled infection. Infection was due to Enterococcus in three instances and to an unknown organism in one. Total ischemic times averaged 2 hours, 15 minutes; a 25 mm Dacron graft containing a porcine valve was used to replace the ascending aorta and aortic valve, and two or three saphenous vein grafts were placed to distal coronary arteries. One patient died 40 days postoperatively of renal failure and Pseudomonas pneumonia with an intact repair. The other three patients were hospital survivors, with one doing well until dying of chronic active hepatitis 12 months postoperatively. The other two patients are alive at 4 months and 18 months with satisfactory hemodynamic function and are free of infection. Translocation of the aortic valve for prosthetic valve endocarditis is a useful alternative when conventional replacement techniques cannot be utilized.

Adult↗
PubMed1980

Sequential orthotopic heart transplantation in man.

Between January 1968 and March 1980, 202 hearts had been transplanted into 185 patients at Stanford University Medical Center. Occasionally, patients after transplantation develop myocardial failure which is amenable only to retransplantation. Sixteen patients underwent initial orthotopic allograft using standard techniques. Eight patients developed accelerated arteriosclerotic coronary disease, six had unrelenting rejection, and two had donor heart dysrrhythmia or right ventricular failure requiring retransplantation. One patient required a third transplant because of donor left ventricular ischemia. All sequential transplants were managed similarly to the primary transplant. Of the initial transplant hearts at risk, 60% survived for more than 1 year, and 57% survived for more than 2 years. These results are similar to those of patients not requiring retransplantation. Of the secondary transplant hearts at risk, 31% survived for more than 1 year and 29% survived for more than 2 years. The severity of infection and/or rejection contributed most significantly to secondary heart transplant mortality. Sequential orthotopic cardiac transplantation offers an acceptable alternative to patients with allograft failure. Survival is not as favorable as with initial transplantation because of the prolonged immunosuppression during sequential transplantation.

Graft Rejection↗
PubMed1980

Distant heart procurement for human transplantation. Ultrastructural studies.

The paucity of donor hearts for human transplantation can be remedied by distant heart procurement. In the present study, 12 donor hearts obtained at distant locatins were preserved by infusion with 500 ml of cardioplegic solution at 4 degrees C at 150 mm Hg and immersion in 4 degrees C saline for rapid transmural cooling. They were transported in ice-cold saline. Maximal ischemic times were 110-182 minutes. Septal biopsies before coronary reperfusion showed normal mitochondria (11 and 12), normal nuclei (seven of 12), myofibrillar I-bands (six of 12), and capillary endothelial swelling (12 of 12). Septal biopsies 30 minutes after reperfusion showed mitochondrial swelling (six of 10), nuclear damage (10 of 10), myofibrillar contraction (10 of 10), and endothelial swelling (eight of 10). All grafts functioned satisfactorily. Eight of the 12 patients were alive 6-15 months later; four patients died (one of pulmonary hypertension and three of infection). We concluded that (1) human hearts show significant ultrastructural changes after 3 hours of ischemia, but (2) these worsen after reperfusion, and (3) distant heart procurement is feasible for human transplantation.

Cell Nucleus↗