Search PubMed⌕ Search

Biomedical subjects

J K Wright

Publications and source records attributed to J K Wright.

At least 109 records · Page 6Linked to original sources
PubMed1982

Lymphocyte cytotoxicity in systemic sclerosis: no increase on short-term culture with established human cell lines.

Lymphocyte cytotoxicity towards 4 established human epithelial and fibroblast cell lines was investigated in 18 patients with systemic sclerosis by means of both whole blood and peripheral blood mononuclear cells in short term (18 h) Cr-release assays. No difference in the levels of cytotoxicity was found in patients compared with 25 normal controls, even when allowance was made for the severity of the disease and the sex of patients and controls. It is suggested that long-term (3-6 days) culture may be necessary to demonstrate the increased lymphocyte cytotoxicity originally described in the disorder.

Adult↗
PubMed1981

Use of the soleus muscle flap to cover part of the distal tibia.

A method for covering soft-tissue defects overlying the distal tibia with a proximally based soleus muscle flap is described. The flap can be used to cover a portion of the distal tibia by extending the distal reach of the soleus muscle. The muscle is extended by several relaxing incisions in the epimysium. This simple procedure enables the soleus muscle to be advanced distally, extending its application for coverage of the distal lower leg. The method has been used successfully clinically, eliminating the need for more time-consuming or difficult procedures.

Adult↗
PubMed1981

Antibody-dependent and phytohaemagglutinin-induced lymphocyte cytotoxicity in systemic lupus erythematosus.

An investigation of cell-mediated cytotoxicity in 22 patients with systemic lupus erythematosus (SLE), using both whole blood and purified peripheral blood mononuclear cells (PBM) to measure antibody-dependent (ADCC) and phytohaemagglutinin (PHA)-induced lymphocyte cytotoxicity for Chang liver cells, has revealed 2 distinct abnormalities in patients with active disease. PHA-induced cytotoxicity was found to be selectively reduced in whole blood assays only (P less than 0.05), whereas ADCC was impaired in both whole blood (P = 0.02) and PBM (P less than 0.05) assays, when comparison was made with 52 normal controls. The addition of patients' sera to corresponding assays utilizing control PBM confirmed that the impaired PHA-induced cytotoxicity resulted from circulating inhibitory serum factors. Surprisingly little effect, however, was exerted on ADCC assays. These findings suggest that there is a reduction in numbers and/or functional capacity of Fc-receptor cells in active SLE, which may have pathogenetic implications.

Adult↗
PubMed1981

Impaired immunity in patients with inflammatory bowel disease and hyposplenism: the response to intravenous phi X174.

Eight patients with inflammatory bowel disease were tested for their ability to mount a serological response to the intravenous particulate antigen phi X174. Seven patients had extensive ulcerative colitis and one patient extensive Crohn's colitis, four having severe hyposplenism and four normal splenic function. The antibody response to phi X174 was grossly impaired in those with hyposplenism.

Antibodies, Viral↗
PubMed1980

Preparation and characterization of chemically defined oligomers of rabbit immunoglobulin G molecules for the complement binding studies.

Pure dimers, trimers, tetramers and pentamers of rabbit non-immune IgG (immunoglobulin G) or antibody IgG were prepared by polymerization in the presence of the bifunctional cross-linking reagent dithiobis (succinimidylpropionate). Oligomerization was performed either in the presence of polysaccharide antigen and specific monomeric antibody (method A) or by random cross-linking of non-immune rabbit IgG in the absence of antigen (method B). By repeated gel-filtration chromatography, samples prepared by both methods exhibited a single band in analytical sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. The electrophoretic mobilities of samples prepared by method A were slightly greater than those for the corresponding samples prepared by method B. This might suggest a role played by antigen in the orientation of IgG molecules within the clusters, which may be more compact than those formed by random cross-linking. The average numbers of cross-linker molecules per oligomer varied between 3 and 6 for clusters made by method A and between 1 and 3 for clusters made by method B. Ultracentrifugal analyses of the oligomers yielded sedimentation coefficients (S20,w) of 9.6S for the dimer, 11.2S for the trimer, 13.6S for the tetramer and 16.1S for the pentamer. Comparison of the observed sedimentation coefficients with those predicted by various hydrodynamic models suggested these oligomers possessed open and linear structures. Reduction of the cross-linking molecules converted oligomers into monomeric species of IgG. C.d. spectra of some oligomers studied in the range 200-250 nm were essentially the same as that of monomeric IgG molecules, thus strongly suggesting no major conformation changes in IgG molecules within clusters. These oligomers were found to be stable for up to 2 months when stored at -70 degrees C.

Animals↗
PubMed1980

Dimeric, trimeric and tetrameric complexes of immunoglobulin G fix complement.

The binding of pure dimers, trimers and tetramers of randomly cross-linked non-immune rabbit immunoglobulin G to the first component and subcomponent of the complement system, C1 and C1q respectively, was studied. These oligomers possessed open linear structures. All three oligomers fixed complement with decreasing affinity in the order: tetramer, trimer, dimer. Complement fixation by dimeric immunoglobulin exhibited the strongest concentration-dependence. No clear distinction between a non-co-operative and a co-operative binding mechanism could be achieved, although the steepness of the complement-fixation curves for dimers and trimers was better reflected by the co-operative mechanism. Intrinsic binding constants were about 10(6)M-1 for dimers, 10(7)M-1 for trimers and 3 X 10(9)M-1 for tetramers, assuming non-co-operative binding. The data are consistent with a maximum valency of complement component C1 for immunoglobulin G protomers in the range 6-18. The binding of dimers to purified complement subcomponent C1q was demonstrated by sedimentation-velocity ultracentrifugation. Mild reduction of the complexes by dithioerythritol caused the immunoglobulin to revert to the monomeric state (S20,w = 6.2-6.5S) with concomitant loss of complement-fixing ability.

Animals↗
PubMed1980

In vitro and in vivo products of E. coli lactose permease gene are identical.

The lacY gene product synthesised in vitro is identical to lactose permease isolated from cytoplasmic membranes as determined by apparent molecular weight and N-terminal amino acid sequence. The amino acid composition of the in vivo product agrees well with that predicted from the DNA sequence. The data assign the translational start on the DNA sequence and demonstrate that this protein is processed only by deformylation but not by proteolytic cleavage at the N-terminus.

Amino Acid Sequence↗
PubMed1980

Cholecystectomy with closed suction drainage.

In this prospective, consecutive, and nonrandomized study, 200 patients had cholecystectomy in a seven-month period. Half of them had drainage with Penrose drains and the other half with a closed suction system. The average hospitalization was one day shorter in the latter. No complications related to its use were found. Retrospective evaluation appears to indicate some conservation of medical care expenditures.

Cholecystectomy↗
PubMed1980

Lactose carrier protein of Escherichia coli. Structure and expression of plasmids carrying the Y gene of the lac operon.

The previously described hybrid plasmid pC7 which carries lacI+O+delta(Z)Y+A+ on a 12.3 X 10(6)-Mr DNA fragment [Teather et al. (1978) Mol. Gen. Genet. 159, 239-248] was partially digested with the restriction endonuclease EcoRI under conditions reducing the recognition sequence to d(A-A-T-T) and ligated to the vector pB322. lac Y-carrying inserts of various sized (Mr 1.5-4.7 X 10(6)) were obtained. Hybrid plasmid pTE18 (2300-base-pair insert) carries part of the I (repressor) gene, the promotor-operator region, part of the Z (beta-galactosidase) gene, the Y (lactose carrier) gene and part of the A (transacetylase) gene. Upon induction of pTE18-harbouring strains the Y-gene product is expressed at a nearly constant rate for several generations and accumulates to a level of 12-16% of the total cytoplasmic membrane protein. Integration into the membrane leads to active carrier as judged by binding and transport measurements.

Bacterial Proteins↗
PubMed1980

Survival of full-thickness skin grafts over avascular defects.

The ability of full-thickness skin grafts to survive over avascular defects has been studied in rabbits. The size of a nonvascularized defect over which take occurs appears to have an absolute limit. If the graft is returned to its bed and an implant is inserted under the graft once it has become vascularized, the graft can be supported solely by the blood supply from the periphery of the graft over an implant of any size.

Animals↗
PubMed1979

Distinct functions of monoclonal IgG antibody depend on antigen-site specificities.

Intraveneous hyperimmunization of selectivity bred rabbits with streptococcal group A-variant vaccines elicits antibody responses of restricted heterogeneity at high antibody levels. All antisera contain two functionally distinct antibody populations, which can be isolated in single-band purity upon analytical isoelectric focusing. Typical examples of these two kinds of single-band antibodies were investigated in great detail for several parameters by a variety of methods. 85--99% of the streptococcal group A-variant polysaccharide (Av-CHO)-specific antibody in the antisera does not precipitate the isolated 5,000 daltons poly-L-rhamnose antigen, neither agglutinates nor lyses in the presence of complement Av-CHO-coated sheep erythrocytes (SRBC), binds the radio-labeled Av-CHO with an association constant in the ragne of 10(5)--10(6) M-1, and is of terminal specificity (nonreducing end) for the linear Av-CHO. In contrast, the minor fraction of Av-CHO-specific antibody (1--15%) does precipitate the linear Av-CHO, both agglutinates and lyses Av-CHO-coated SRBC in the presence of complement, has an affinity range of 10(8)--10(9) M-1, and is of internal specificity for the Av-CHO. The antigenic determinants of the Av-CHO for the antibodies are nonoverlapping, only one Fab of the low affinity antibody can be bound whereas four Fab of the high affinity antibody are accommodated. Hence, the determinant specificity explains the functional differences observed, for there is no indication of subclass differences. A mechanistic model of the A-variant carbohydrate presentation on the vaccine appears to account best for the unbalanced levels of low and high affinity antibody.

Animals↗
PubMed1979

Clonal dominance of low-affinity antibodies in rabbit hyperimmune anti-streptococcal group A-variant polysaccharide antisera.

Intraveneous hyperimmunization of selectively bred rabbits with streptococcal group A-variant vaccines elicits antibody responses of restricted heterogeneity at high antibody levels. In these antisera, IgG with dissociation constants Kd = 10(-6) M constitutes 90% and IgG with Kp = 10(-9) M accounts for only 10% of the group A-variant polysaccharide-specific antibodies. The low affinity antibody fraction represents the dominant clonotypes. Preparative isoelectric focusing in granulated (Ultrodex G-75) gels was used to successfully purify single-band material belonging to dominant spectrotypes. Affinity studies with these antibody fractions with the highest reported degree of purity yielded Kd = 10(-6) M values, thus confirming that clonal dominance is exclusively associated with low-affinity antibodies. Since it is known from previous work (M. Cramer and D. G. Braun, Scand. J. Immunol. 1975. 4:63) and from the rabbit antisera used here that clonal dominance of this sort is long-lived, this work fails to support the argument of immune maturation. The data more logically relate to antibodies that emerge with different subspecificities -- recognized in the antigen as a function of time in immunization procedures -- rather than to an inherent property of the immune system.

Animals↗
PubMed1979

Isolation of the globular region of the subcomponent q of the C1 component of complement.

Digestion after heat treatment of the subcomponent q of the C1 component of complement by collagenase leads to the isolation of the globular region of the protein. This product ('heads') is composed of three chains giving an overall molecular weight of about 57000. About half of the collagen-like region present in C1 q is lost after digestion. The 'heads' are shown to be soluble and hemolytically active products.

Amino Acids↗
PubMed1979

Amino acid sequences of antibody light chain variable regions of pedigreed rabbits: kappa light chain K49-501 (allotype b4 anti-streptococcal group A-variant polysaccharide antibody).

The amino acid sequence of positions 1--150 of a light chain, isolated from another monoclonal rabbit anti-streptococcal group A-variant polysaccharide antibody, was determined. The analysis was performed with 2 mumol of polypeptide chain, using a grossly modified Beckman 890B sequenator. This sequence stretch accounts for the whole variable region and a considerable part of the constant region at a total length of 218 amino acids. This allotype b4 light chain was isolated from a non-precipitating, end-group-specific antibody with a KD = 1.3 X 10(-5)M. This brings the present number of totally known rabbit VL sequences of antigen elicited antibodies to 21. A comparison of these 21 sequences reveals a building plan of ribbit VL homologous to that of human and murine VL regions. The observed variability does follow a pattern of linked amino acid substitutions, indicating that this information must be contained in the germ-line of the rabbit in the form of multiple VL region genes. This conclusion, however, does not rule out the occasional variant being due to somatic rearrangement. Finally, this comparison reveals that the joining peptide between positions 96--110 is also a separate entity in rabbit VL region sequences.

Amino Acid Sequence↗