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Biomedical subjects

J Williams

Publications and source records attributed to J Williams.

At least 955 records · Page 53Linked to original sources
PubMed1985

Partial trisomy 11p with interatrial septal aneurysm. Case report and literature review.

A newborn female infant presented with hypotonia, joint hyperextensibility, cardiac murmur, macroglossia, and hepatosplenomegaly. Karyotype of the child revealed partial trisomy of chromosome 11p derived from a paternal balanced translocation. Echocardiogram obtained in the newborn period suggested interatrial aneurysm, which was confirmed on post-mortem examination. Interatrial septal aneurysm is a rare abnormality not previously described in partial trisomy 11p.

Chromosome Banding↗
PubMed1984

Analysis of assay errors in drug measurements from the Heathcontrol interlaboratory quality assessment schemes.

Measurements of drug concentrations from the Heathcontrol quality assessment schemes were analysed to detect the presence of intralaboratory, interlaboratory, or intermethod errors. We developed weighted least-squares regression procedures as significance tests for evaluating intralaboratory noise, curvature vs linearity, proportional errors and additive errors. The latter intercept test for additive errors was unsatisfactory and an effective alternative based on the difference between measurements and estimates of the true drug concentrations was developed. Significance of residuals was tested against the population noise, which was defined by smooth mathematical functions fitted to the standard deviation (SD) data for the drug samples. We evaluated these tests for 1,647 sets of data. Only small amounts of curvature were present, validating the linear-regression approach. Both random and proportional errors were demonstrated. The most frequent errors were additive in nature, components of which were demonstrated to be the result of intermethod differences.

Anticonvulsants↗
PubMed1984

Structural analysis of the carbohydrate moieties of human Tamm-Horsfall glycoprotein.

Glycopeptides present in a pronase digest of human Tamm-Horsfall glycoprotein were fractionated by chromatography on DEAE-Sephadex A25 in 0.1M acetic acid. The separated glycopeptides were characterised by 500-MHz 1H-n.m.r. spectroscopy, in conjunction with sugar and amino acid analysis, and they were shown to be of the N-glycosylic, N-acetyllactosamine type. Each fraction consisted mainly of a tetra-antennary entity having various degrees of complexity, with lesser amounts of the triantennary structure, and even smaller amounts of the diantennary type. There was extensive heterogeneity in non-reducing terminal groups in each of the glycopeptides, whereas the peptide portions were similar. The extent to which any one of the galactose residues in the N-acetyllactosamine units was substituted, and the type of substitution, differed. The substituents were alpha-NeuAc-(2----6), alpha-NeuAc-(2----3), and alpha-NeuAc-(2----3)[beta-GalNAc-(1----4)]. The carbohydrate moieties of the glycoprotein were heterogeneous also because of an uneven distribution of the fucose residues, which were attached to GlcNAc residues, both that linked to asparagine and one or more of those present in the N-acetyllactosamine units. The alpha-NeuAc-(2----3)[beta-GalNAc-(1----4)]-beta-Gal-(1---- sequence forms, at least in part, the Sda immunodeterminant. The pKa of the carboxyl group of the sialic acid residue in this entity is lower than that for molecules lacking Gal-NAc in this position. Thus, the difference in the number of Sda determinants carried by the glycopeptides enabled the latter to be fractionated on DEAE-Sephadex.

Amino Acids↗
PubMed1984

Characterization of soluble polymerized fibrin formed in the presence of excess fibrinogen fragment D.

Polymerization of fibrin is inhibited in the presence of excess fibrinogen fragment D. This study was performed in order to test the proposal that these inhibited solutions contain short linear polymers of fibrin (protofibrils) whose further polymerization is prevented as a result of attachment of a molecule of fragment D at each end. Negative-stain electron micrographs, intrinsic viscosities, angular dependence of light scattering intensity, and kinetics of the increase of the scattered intensity with polymerization all were found to support the above model of the inhibited polymer and to reflect the presence of a broad distribution of the lengths of the inhibited fibrin polymers. Furthermore, sodium dodecyl sulfate-polyacrylamide gel electrophoresis of polymers stabilized with gamma-dimer cross-links introduced by factor XIIIa demonstrates cross-linking of fragment D to fibrin oligomers. Cross-linked polymers have been separated from excess fragment D by gel exclusion chromatography in 1 M urea. (In the absence of urea, the purified polymers very slowly associate to fibers.) The observation of the relative stability of short isolated inhibited protofibrils and the decrease or absence of inhibition of fibrin gelation when fragment D was added to solutions in which fibrin had been given time to polymerize to long protofibrils demonstrate that the inhibitory effect of fragment D occurs as a result of inhibition of the first fibrin polymerization step.

Animals↗
PubMed1984

Angiodysplasia of the colon. A review of 17 cases.

From October 1977 through December 1982, 24 patients with lower gastrointestinal tract hemorrhage were diagnosed by visceral angiography as having angiodysplasia of the colon. Seventeen of them underwent surgery for definitive treatment of their hemorrhage. Five patients had lesions on both sides of the colon, and five had coagulation disorders. Three of the 17 patients with lesions isolated to the cecum underwent right hemicolectomy. The rest underwent subtotal colectomy with ileoproctostomy. No patient had recurrent or persistent bleeding. There were three deaths in the subtotal colectomy group (21%); coagulation disorders contributed to two of them. Subtotal colectomy was universally successful in controlling bleeding but had a significant mortality in these elderly patients. Coagulopathy, especially platelet disorders, was a significant risk factor with this diagnosis. A coagulation panel, including platelet function, should be part of the preoperative assessment.

Aged↗
PubMed1984

Muscle changes in venous insufficiency.

The diagnosis of venous insufficiency and hypertension was established in 53 patients using standard diagnostic methods including ascending and descending venography, venous pressure measurements, and photoplethysmography. Autogenous vein valve transplant, which is gaining acceptance as a treatment for this condition, was employed in this group of patients to relieve venous valvular insufficiency. Biopsy specimens of the gastrocnemius muscle were obtained before surgery in all 53 patients and studied pathologically. Three types of morphologic injury were encountered, suggesting that disuse, denervation, and ischemia may each be partially responsible for damage in skeletal muscle subjected to venous insufficiency and hypertension. Skeletal muscle injury probably explains the preoperative elevations of serum creatine kinase levels in many of our patients and may account for the failure of venous pressures to return to normal levels following surgery.

Biopsy↗
PubMed1984

Human breast epithelium transplanted into nude mice. Proliferation and milk protein production in response to pregnancy.

Epithelial components of the normal human breast and their response to hormonal manipulation have been studied in the nude mouse. Six to eight week-old female athymic nude mice were used as the recipients of enzymatically prepared breast organoids, composed of ductal and lobuloalveolar structures. After 12 weeks in situ in the mouse mammary fat pad the human breast tissue retains its normal morphology as demonstrated by the presence of myosin positive myoepithelial cells and keratin positive luminal cells. Monoclonal antibodies M8 and M18 raised to components of the human milk fat globule membrane give a similar staining pattern in the xenografted organoids to that seen in the donor tissue. On mating the recipient female nude mice, the human breast tissue responds with both an increased 3H-thymidine labelling index and alpha-lactalbumin production. This model in conjunction with in vitro studies is, therefore, suitable for the study of extrinsic and intrinsic factors controlling differentiation and morphogenesis in the human breast.

Adult↗
PubMed1984

Regulative interactions between cells of wing discs from different dipteran species.

The mechanism by which patterns are produced appears to be repeated in each segment of an animal, and it has been proposed that it may even have been conserved in evolution so that different species would have the same system of positional information. This idea has been tested by mixing cells of a defined fragment of the wing disc of Drosophila melanogaster with wing disc fragments of five other dipteran species to assay the ability of these disc fragments to stimulate intercalary regeneration of the D. melanogaster cells. The genetically marked (y; mwh) D. melanogaster fragment was mechanically mixed with wing discs or wing disc fragments of four drosophilids (D. melanogaster as a control, D. virilis, D. hydei, Zaprionus vittiger), of Musca domestica, and of Piophila casei. The mixed aggregates were cultured in vivo for 7 days, then metamorphosed in D. melanogaster larval hosts. The D. melanogaster fragments were only stimulated to regenerate when combined with complementary fragments from D. melanogaster or D. virilis wing discs. In the combination between D. melanogaster and D. hydei, the tissue formed integrated mosaic patterns, but no regeneration ensued. The one positive result (D. melanogaster mixed with D. virilis) shows that positional cues can be exchanged and correctly interpreted between cells of different species. The negative results do not prove that the mechanism for establishing patterns is different in the tested species, but may be due to incompatibilities that are not related to pattern formation.

Animals↗
PubMed1984

Manifestations of resistance to ovine ostertagiasis associated with immunological responses in the gastric lymph.

Groups of previously infected and worm-free sheep were serially killed up to 10 days after challenge with 50 000 Ostertagia circumcincta larvae. Two similar groups of sheep were killed 10 days after challenge with 1000 larvae. The previously infected sheep were resistant to the smaller challenge dose in that fewer, stunted worms were recovered from them than from controls. However, this resistance was not as marked as that observed in the previously infected sheep which received the large challenge, because proportionally fewer worms were recovered after the 50000 dose and the great majority of these were arrested at the early fourth stage. The gastric lymph ducts of 6 previously infected sheep were cannulated successfully and a marked local immune response was detected in 3 sheep which were challenged with 50 000 larvae. No response was detected in 3 cannulated sheep challenged with 1000 larvae. In the lymph of the 50 000 dose group, a temporary increase in pepsinogen activity suggested that a hypersensitivity reaction related to the presence of large numbers of mucosal mast cells began between 24 and 48 h after challenge. This was followed by marked increases in the cellular and IgA content of lymph, which reached peaks on days 3 and 6, respectively. It is suggested that the response detected in the gastric lymph reflected aspects of a local immune reaction in the abomasal mucosa and that this reaction accounted for the enhanced degree of resistance to the larger challenge dose.

Animals↗