Search PubMed⌕ Search

Biomedical subjects

J Williams

Publications and source records attributed to J Williams.

At least 1,135 records · Page 63Linked to original sources
PubMed1975

A comparsion of glycopeptides from the transferrins of several species.

1. The carbohydrate compositions of human, pig and cattle transferrins and duck ovotransferrin have been determined. 2. Glycopeptides have been prepared from these transferrins and their carbohydrate compositions and amino acid sequences determined. One of the glycopeptides from human transferrin carries the C-terminal residue of the protein. 3. Each tranferrrin yielded two glycopeptides that appeared to be identical in carbohydrate composition but different in amino acid sequence. The two glycopeptides have been distinguished as type A, in which the residue following Asn(CHO)(where CHO represents a carbohydrate moiety) is a basic amino acid and type B in which Asn(CHO) is followed by a neutral aliphatic amino acid. Cattle transferrin is exceptional in having two glycopeptides in which this position is occupied by serine. 4. It is suggested that each molecule of human and cattle transferrin and duck ovotransferrin carries an average of two carbohydrate prosthetic groups. Hen and pig transferrins appear to carry only one carbohydrate group per mol of protein. 5. The N-terminal sequences of hen and duck ovotransferrins and of cattle, human and pig transferrins were also determined.

Amino Acid Sequence↗
PubMed1975

The amino acid sequence of a carbohydrate-containing fragment of hen ovotransferrin.

1. Hen ovotransferrin was treated with CNBr and fractionated by gel filtration. 2. After further treatment by reduction and carboxymethylation a carbohydrate-containing fragment of molecular weight 11990 was obtained (fragment BCd). 3. The amino acid sequence of this fragment was determined. It consists of a single chain of 94 residues. 4. The structure of a tryptic glycopeptide derived from whole ovotransferrin permitted a further eight residues to be assigned at the N-terminus of fragment BCd. 5. Heterogeneity was found at two positions. 6. Further evidence has been deposited as Supplementary Publication SUP 50045 (19 pages) at the British Library (Lending Division), Boston Spa, Wetherby, W. Yorkshire LS23 7BQ, U.K., from whom copies may be obtained on the terms indicated in Biochem. J. (1975), 145, 5.

Amino Acid Sequence↗
PubMed1975

Iron-binding fragments from the carboxyl-terminal region of hen ovotransferrin.

1. When iron-saturated hen ovotransferrin was treated with subtilisin the N-terminal half was digested at a faster rate than the C-terminal half, allowing the latter to be isolated as a single-chain fragment of mol.wt 35000. 2. In mildly acid conditions iron-ovotransferrin loses iron preferentially from its N-terminal binding site. Trypsin digestion of the resulting monoferric ovotransferrin also gave rise to a C-terminal fragment. 3. Comparison of the N-terminal fragment with the C-terminal fragments shows differences in composition, peptide 'maps', CNBr-cleavage patterns and antigenic structures. The C-terminal fragments carry the carbohydrate group of ovotransferrin. 4. Both N-terminal and C-terminal fragments donate their bound iron to rabbit reticulocytes.

Amino Acid Sequence↗
PubMed1975

Electron-paramagnetic-resonance spectroscopy of iron-binding fragments of hen ovotransferrins.

1. It is confirmed that there are two e.p.r. (electron-paramagnetic-resonance) signals associated with fully loaded ovotransferrin, which has two iron-binding sites. 2. Through experiments in which either of the two sites of whole ovotransferrin is occupied, the other being empty, the first occupied site is shown to belong to the N-terminal region of the protein; the second occupied site is in the C-terminal region. 3. When the protein is cleaved with trypsin or subtilisin, the N-terminal fragments are spectroscopically similar to the monoferric ovotransferrin complexes in which the iron atom occupies the N-terminal or C-terminal site respectively. Each fragment displays the same two e.p.r. signals, though not in the same proportions. 4. Computer summations of the e.p.r. spectra confirm that there is no iron-iron interaction which affects the spin Hamiltonian parameters at the iron-binding sites.

Binding Sites↗
PubMed1975

Changes in flow and pressure due to rotation of a saphenous vein segment.

The effect of axial rotation on flow through and pressure gradient across saphenous vein segments was studied using 15 cadaver long saphenous veins. A significant reduction in flow occurred at a mean rotation of 25 degrees/cm and a significant increase in head loss across the segments occurred at a mean rotation of 23 degrees/cm. Collapse of the vein segments occurred at a mean rotation of 27 degrees/cm.

Blood Flow Velocity↗
PubMed1975

Optimal length of a saphenous vein segment when used as an arterial substitute.

An in-vitro experiment using 12 cadaver long saphenous veins was performed to determine the optimal length of a saphenous vein segment intended for use as an arterial substitute. This length was found to be 8% greater than the body length, as judged by maximal flow through the veins and 6% greater than body length judged by minimal pressure loss across the vein segments. Extreme extension of the veins resulted in incomplete transverse rupture of the inner layers of three of the veins tested.

Arteries↗
PubMed1975

The cardiovascular effects of dantrolene sodium in dogs.

The effects of the intravenous infusion of dantrolene sodium and of equal volumes of normal saline on arterial pressure, central venous pressure, heart rate and cardiac output have been investigated in healthy, anaesthetised dogs. The infusion of dantrolene in the manner and dose found to be effective by other workers in pigs-8 for the treatment of anaesthetic induced malignant hyperpyrexia, produced changes which differ little from those observed after the infusion of a similar quantity of saline. These results are discussed.

Animals↗
PubMed1975

Serum gonadotrophins in young children.

LH and FSH were assayed in serum samples from children ranging from newborn to 13 years. In boys, LH was found in most samples up to 4 months of age, in many up to 10 months, but in only 38 percent between 1 and 8 years. In girls, it was found in only 29 percent of the samples under 1 year and the frequency and concentration changed little thereafter until 8-10 years. FSH was detected in all samples from boys up to 4 months and in most of those from girls up to 2 years. After these ages the frequency declined in each sex and there was little further change until 8-10 years. Between 1 and 8 years the proportion of samples containing either FSH or LH was similar for the two sexes, but whereas in boys high LH tended to be associated with high FSH, and vice versa, there was no such correlation in girls. The results are discussed in relation to gonadal development and steroid synthesis.

Adolescent↗
PubMed1975

Influence of substrate wettability on the attachment of marine bacteria to various surfaces.

The effect of the initial substrate surface condition, as indicated by the critical surface tension for wetting, on the rate of attachment of marine bacteria to a variety of solid surfaces has been measured. The techniques used to determine the number of bacteria attached per unit surface area were a lipopolysaccharide test utilizing Limulus lysate and direct examination of the surface by scanning electron microscopy. The results obtained by the two techniques are compared and their significance to the control of microbiological slime film formation (microfouling) is discussed.

Journal Article↗
PubMed1975

Complementation of human adenovirus type 5 ts mutants by human adenovirus type 12.

Temperature-sensitive mutants of type 5 adenovirus belonging to eight complementation groups were complemented in mixed infection by type 12 adenovirus, whereas mutants of 7 other groups were not enhanced. In some crosses, phenotypic mixing took place. No evidence of recombination between type 5 ts mutants and type 12 was found.

Adenoviridae↗
PubMed1975

Familial non-cystic fibrosis mucus inspissation of respiratory tract.

Perlman, M., Williams, J., Hirsch, M., and Bar-Ziv, J. (1975). Archives of Disease in Childhood, 50, 727. Familial non-cystic fibrosis mucus inspissation of respiratory tract. Two sibs, whose parents are first cousins, have had chronic obstructive airways disease from birth with recurrent otitis media, sinusitis, and mastoiditis. The disease, associated with clinically abnormal mucus, differs from other familial obstructive airways diseases and probably constitutes a new entity.

Airway Obstruction↗