Search PubMed⌕ Search

Biomedical subjects

L King

Publications and source records attributed to L King.

At least 109 records · Page 6Linked to original sources
PubMed1989

Impact of percutaneous renal stone removal on renal function: assessment by urinary lysozyme activity.

Lysozyme in the urine in concentrations greater than 3 micrograms per milligram of creatinine reflects renal tubular disease or dysfunction in patients without bowel disease or leukemia. We therefore used urine lysozyme assays to assess renal response to percutaneous nephrostomy and stone removal in 42 patients. Eight patients had striking increases (4.2-21.1 [mean 7.58] micrograms/mg creatinine) immediately after nephrostomy puncture in urine obtained directly from the punctured kidney. Lysozyme declined sharply thereafter and was within normal limits in all cases by postoperative day 3. This increase appeared to result from bleeding into the urine from the tract. Five other patients had lysozymuria on admission, only 1 of whom had a sharp increase after nephrostomy puncture. In the remaining patients, the lysozyme levels remained within normal limits throughout the hospital course. These data are further evidence of the absence of significant deleterious effects of nephrostomy puncture on the kidney.

Acute Kidney Injury↗
PubMed1989

Unique V gene usage by B-Ly1 cell lines, and a discordance between isotype switch commitment and variable region hypermutation.

We have previously described a series of Ly-1+ B cell lines obtained as spontaneous outgrowth cultures from mouse spleen cells (B-Ly1 cells). In this study, we report the variable region sequences utilized by independent cell lines derived from three mouse strains. Remarkably, V region utilization and junctional diversification were essentially identical in all three cell lines. These included: lambda 1 light chain; JH1; DSP2-7,8; and, a novel VH gene segement. The VH was highly homologous to CP4, a rare VH family previously found in a group of Ly-1 B cell-derived autoantibodies to bromelain-treated mouse red blood cells. The selective expression of this unusual lg species implies the action of distinctive molecular or immunophysiological processes in the outgrowth of B-Ly1 cell lines. Clarification of these factors may be relevant to understanding the peculiar biology of Ly-1 B cells in vivo. We have also evaluated switch-committed B-Ly1 clones to determine whether this phenotype is accompanied by variable region somatic mutation. However, no evidence for somatic mutation was observed in these induced clones. This may indicate that these two processes are independently regulated, despite their common concordance in vivo.

Amino Acid Sequence↗
PubMed1988

Complete nucleotide sequence of a mouse VL30 retro-element.

The complete nucleotide sequence of a mouse retro-element is presented. The cloned element is composed of 4,834 base pairs (bp) with long terminal repeats of 568 bp separated by an internal region of 3,698 bp. The element did not appear to have any open reading frames that would be capable of encoding the functional proteins that are normally produced by retro-elements. However, some regions of the genome showed some homology to retroviral gag and pol open reading frames. There was no region in VL30 corresponding to a retroviral env gene. This implies that VL30 is related to retrotransposons rather than to retroviruses. The sequence also contained regions that were homologous to known reverse transcriptase priming sites and viral packaging sites. These observations, combined with the known transcriptional capacity of the VL30 promoter, suggest that VL30 relies on protein functions of other retro-elements, such as murine leukemia virus, while maintaining highly conserved cis-active promoter, packaging, and priming sites necessary for its replication and cell-to-cell transmission.

Amino Acid Sequence↗
PubMed1988

The EDTA extractable protein is glycosylated in the bovine lens.

The EDTA extractable protein (EEP) can be prepared from the bovine lens using sonication; however, urea washing of the membrane fraction was essential in decreasing the non-specific binding of the crystallins to the EEP fraction. Both the 32 and the 35 kilodalton (kD) proteins from EEP were shown to be glycoconjugates using periodate labelling. The EEP from the lens bound a variety of lectins at both 32 and 35 kD. The binding of the lectins suggested that EEP is composed of proteins having galactose or N-acetylgalactosamine groups as well as fucose residues. The glycosylation of EEP adds another possible regulatory step for the control of these calcium binding proteins in the lens.

Animals↗
PubMed1987

The action of erythropoietin is mediated by lipoxygenase metabolites in murine fetal liver cells.

Erythroid progenitor cells synthesize 12-hydroxyeicosatetraenoic acid (12-HETE) and 15-hydroxyeicosatetraenoic acid (15-HETE) when stimulated by erythropoietin (Ep). Maximal stimulation of 12-HETE production occurred at one hour, whereas 15-HETE activity remained constant in response to Ep for 24 hours. Lipoxygenase-selective inhibitors of arachidonic acid metabolism blocked HETE production and Ep-stimulated growth and differentiation of erythroid progenitor cell-derived colonies (CFU-E). On the other hand, specific inhibitors of cyclooxygenase (aspirin and meclofenamate) did not significantly inhibit Ep-induced erythroid colony formation. It is hypothesized that the stimulation of HETE production from arachidonic acid (AA) is an essential step in the mechanism of action of Ep.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1987

The best suture for hypospadias?

In a study designed to determine the best suture for use in hypospadias surgery, polydioxanone (PDS), chromic catgut, and polyglycolic acid (Dexon) were studied under similar conditions in the penile foreskin of 16 baboons. Gross and microscopic observations were made at intervals of six to forty-eight days. The wounds sutured with catgut were all healed by twenty-four days with complete suture resorption and no evidence of scar formation. Both polyglycolic acid and polydioxanone sutures showed delayed resorption, wound abscesses, and granulomas. Catgut remains the best available suture to use in the penile foreskin. Polyglycolic acid and polydioxanone sutures, because of their prolonged resorption and excess reaction, should not be used in hypospadias surgery.

Animals↗
PubMed1987

Bond strengths of lingual orthodontic brackets bonded with light-cured composite resins cured by transillumination.

A method of curing light-cured composite resins by transillumination to cement acid-etched fixed partial dentures was adapted to bond solid mesh-backed lingual orthodontic brackets. Results of this investigation showed that the bond strengths of the orthodontic brackets bonded with light-cured composite resins were significantly less (P less than 0.05) than the bond strengths of the orthodontic brackets cemented with traditional adhesives and orthodontic composite resins. Notwithstanding, the bond strengths achieved with the transilluminated light-cured composite resins should be adequate to withstand the forces of mastication and orthodontic movements. There was no correlation of bond strengths of the brackets cemented with the transilluminated light-cured composite resins when compared to the faciolingual widths of the teeth.

Acrylic Resins↗
PubMed1987

In vitro comparison of the properties of polydioxanone, polyglycolic acid and catgut sutures in sterile and infected urine.

The effect of immersion in sterile urine, infected urine and plasma on the breaking strength and stiffness of polydioxanone (PDS), polyglycolic acid (PGA) and chromic catgut was studied. Tests were done under closely controlled conditions with immersion periods varying from zero to ten days. The breaking strength and stiffness of the three suture materials was not significantly changed by immersion in plasma for periods up to ten days. In sterile urine, PDS lost all of its strength after three days of immersion while PGA lost 64% of its initial breaking strength after ten days. Catgut maintained its strength over the ten day study period. In E. coli-infected urine, PDS lost all of its strength in six days while PGA lost 71% and catgut 8% after ten days. In proteus-infected urine, PDS and PGA lost all their breaking strength after one day of immersion while catgut lost 5.8% of its initial strength after 10 days. Corresponding decreases in stiffness were also observed.

Bacteriuria↗
PubMed1987

Bracing of thoracic and lumbar spine fractures.

A prospective study of the non-operative management of 33 thoracic and lumbar fractures and dislocations was undertaken examining factors such as duration of bed rest and brace prescription. Outcome was assessed using Frankel's grading system and serial radiological examination. Bed rest for 6 to 8 weeks followed by 16 weeks of immobilisation in a thoraco-lumbar orthosis (either a moulded plastazote lined polythene brace or a Taylor brace) resulted in less than 15 degrees kyphus in 85% of patients and less than 20% kyphus in 94%. One patient with a T12/L1 dislocation who had an early decompressive laminectomy showed persistent instability and required internal fixation. One patient with an L1 fracture who initially wore a Hexalite brace developed late instability (at 12 months after injury) and required spinal osteotomy and fusion. Neurological improvement was observed in 50% of patients, and no permanent neurological deterioration occurred. A non-operative regimen of treatment of fractured thoracic and lumbar vertebrae as described is an alternative to prolonged immobilisation in bed, or early operative fusion.

Braces↗
PubMed1987

Conversion of phosphatidylglycerol to lyso(bis)phosphatidic acid by alveolar macrophages.

We report here studies of the synthesis of lyso(bis)phosphatidic acid [L(b)PA] by normal and BCG-elicited rabbit alveolar macrophages. This study was prompted by our earlier observations that 1) alveolar macrophages did not synthesize L(b)PA de novo despite its abundance in these cells, 2) BCG-elicited cells contained only one-quarter the amount of L(b)PA as normal cells, and 3) the turnover of arachidonate in L(b)PA led to hydroxyeicosatetraenoic acid and leukotriene synthesis. We found that exogenous phosphatidylglycerol (PG) was specifically converted to L(b)PA by both types of cells although BCG-elicited cells had only one-quarter the synthetic capacity of normal cells. Other phospholipids were found to become cell associated but were not significantly metabolized. Both glycerol moieties and the phosphate were incorporated into the product L(b)PA. However, substitution of the ester with an alkyl linkage in position 1 blocked the conversion of PG to L(b)PA. Most of the alkylphosphatidylglycerol was converted to phosphatidylcholine and phosphatidylethanolamine. This result implied that catabolism of the acyl group in position 1 was essential for L(b)PA synthesis. Because alveolar macrophages are present in a surfactant-rich milieu, we suggest that surfactant provides a source of PG for macrophage synthesis of L(b)PA in situ. It is interesting that the surfactants from rabbits challenged with BCG have a significant decrease in PG content.

Animals↗
PubMed1986

Conformational drift of dissociated lactate dehydrogenases.

Bovine and porcine lactate dehydrogenases, in solutions of 0.1-10 microM at neutral pH, dissociate into monomers upon application of hydrostatic pressures of up to 2 kbar. The dissociation was determined from observations of the polarization of fluorescence under pressure in seeming equilibrium conditions and by occasional hybridization experiments of the H4 and M4 isozymes. Decompression is followed by the rapid association of the monomers into tetramers and by slow, and sometimes incomplete, return of the enzymic activity. The dissociation curves obtained on compression and decompression differ, indicating that association results in partial loss of subunit affinity. These phenomena are attributed to a slow conformational drift that follows the loss of contact of the monomers with each other and to an even slower reversal of the drift that takes place upon reassociation.

Animals↗
PubMed1986

Conformational drift and cryoinactivation of lactate dehydrogenase.

Solutions of porcine lactate dehydrogenase of micromolar concentration kept at 4 degrees C for several days lose the greater part of their enzymic activity but recover it when returned to room temperature. The rate of spoiling decreases and the rate of recovery increases with the concentration of the solutions. The decrease in tetramer stability in the cold is shown by experiments of pressure dissociation at various temperatures and confirmed because isozyme hybridization occurs in parallel with the inactivation at low temperature but is absent at room temperature. Cold-inactivated solutions contain tetramers that dissociate much more readily than those of the fully active solutions. It is postulated that cryoinactivation, like pressure inactivation, takes place through a cycle of dissociation, conformational drift [King, L., & Weber, G. (1986) Biochemistry (second paper of three in this issue)] and reassociation into inactive tetramers.

Animals↗
PubMed1986

B-Ly1 cells: immortal Ly-1+ B lymphocyte cell lines spontaneously arising in murine splenic cultures.

We have surveyed the molecular and functional properties of B-Ly1 cells, spontaneously occurring Ly-1+ cell tissue cultures lines established from murine spleen. Several features are surprising when compared to the conventional understanding of B cell physiology: In contrast to the major B cell subpopulation, these cells establish stable in vitro lines in the absence of nominal growth factors. This outgrowth is consistently accompanied by c-myc amplification and deregulation, and resistance to the effects of an autoregulatory IgM species which normally curtails the growth of B cells. These properties may be relevant to the disproportionate occurrence of Ly-1+ B cell malignancies in vivo. B-Ly1 cell lines consistently delete immunoglobulin constant region genes, and uniformly express lambda light chains, a rare murine isotype. These features may be causally related, and may reflect a novel recombinational activity (see this volume). Immunoglobulin expression can be modulated by conventional stimuli. However, the response is transient, and includes production of mature heavy chain isotypes ("class switching") without apparent switch deletion. Moreover, unstimulated B-Ly1 cells show transcriptional activity throughout the heavy chain locus, and a novel hypermutation activity affecting the immunoglobulin variable region. The mechanisms underlying this surprising pattern of immunoglobulin expression are unknown. However, one wonders whether this expression pattern, if common to Ly-1+ B cell in vivo, might provide modes to escape idiotypic or isotypic immunoregulation. If so, this may be relevant to the prevalence of autoantibody production by this subpopulation. Thus, we are hopeful that some of these unique properties, if confirmed in the Ly-1+ B cells in vivo, will provide more definitive markers for this subpopulation, and disclose mechanisms accounting for their distinctive physiology and pathophysiology.

Animals↗