Biomedical subjects
C L Jones
Publications and source records attributed to C L Jones.
Microbiological and clinical effects of a dentifrice containing zinc citrate and Triclosan in the human experimental gingivitis model.
A partial mouth experimental gingivitis model was employed to establish the effect of a dentifrice containing 0.2% Triclosan and 0.5% zinc citrate on the development of chronic gingivitis. In addition, changes in the plaque flora associated with the developing gingivitis have been monitored. Following a period of stringent oral hygiene, volunteers were allocated to 1 of 2 treatment groups. A toothshield was constructed to fit 4 posterior mandibular teeth. During the 21-day experimental period test or placebo dentifrice was applied to the experimental teeth via the tooth shield. The toothshield also prevented plaque removal from those teeth during habitual brushing of the remaining dentition. Supragingival plaque was collected at baseline and day 21 for analysis of the total bacterial flora. At the end of the experimental period, plaque and gingivitis had developed in both groups. However, the test group had significantly less plaque and gingivitis than the placebo group. The microbiological data demonstrated that plaque from the test group contained significantly lower numbers of anaerobes compared to plaque from the placebo group. This was considered particularly significant as these bacteria are generally associated with chronic inflammatory periodontal disease. There was also a trend for the numbers of actinomyces to decrease in plaque from the test group but not in the placebo group.
An oligonucleotide probe to assay lysis and DNA hybridization of a diverse set of bacteria.
A computer bank of 16 S rRNA bacterial sequences was searched to determine a consensus sequence expected to hybridize with DNA from a wide variety of bacteria. An oligonucleotide probe, named a panprobe, containing this sequence was used to assay the degree of lysis of bacterial colonies on filter paper heated in a microwave oven and subsequently treated with NaOH. As determined by colony hybridization with the panprobe, lysis was achieved for 51 of 59 different species of bacteria tested. DNA, isolated from the eight bacteria not detected by colony hybridization, did hybridize with the panprobe in slot blot hybridizations.
Comparative developmental toxicity of cationic and neutral rhodamines in mice.
Rhodamines 123 and 6G (Rh 123 and Rh 6G) are cationic fluorescent dyes that inhibit oxidative phosphorylation following their selective accumulation within mitochondria. Neutral rhodamines (e.g., Rh 116 and Rh B) do not share these properties. To determine if cationic and neutral rhodamines differ in their effect on mammalian development, pregnant CD-1 mice were injected i.p. with Rh 123, Rh B, or Rh 116 at doses of 15 mg/kg/day. The rhodamines were given alone or in combination with 500 mg/kg/day 2-deoxy-D-glucose (2-DOG), an inhibitor of glycolysis, daily on gestation days 7-10 (copulation plug = day 1). Additional pregnant mice were similarly treated with Rh 6G at a dose of 0.5 mg/kg/day. Controls were given saline equimolar to the dose of 2-DOG. Treatment with Rh 6G, alone or in combination with 2-DOG, significantly increased the incidences of prenatal mortality (17% and 35%, respectively) when compared with the control incidence (6%). Treatment with Rh 123 or Rh 6G, alone or with 2-DOG, inhibited fetal growth. Treatment with the neutral rhodamines had little effect on prenatal survival or growth. Exposure to Rh 6G, with or without 2-DOG, was associated with high incidences of gross malformations (41% and 61%, respectively). Rh 116 or Rh B, with or without 2-DOG, and Rh 123 alone were not associated with statistically significant teratogenic effects, but results of the latter treatment were suggestive of such an effect (9.1% grossly malformed fetuses vs. 0% for controls). The incidences of skeletal malformations were significantly increased in the test groups given Rh 6G + 2-DOG, Rh 123 + 2-DOG, or Rh 6G alone.(ABSTRACT TRUNCATED AT 250 WORDS)
Antibodies to polyclonal IgA, IgA1, and IgA2 and isotype-specific immune complexes in IgA nephropathy.
The concentrations of serum IgG and IgM antibodies to polyclonal IgA (IgAp), IgA1, and IgA2 were determined by enzyme immunoassay in 31 patients with IgA nephropathy and 30 healthy controls. Patients with IgA nephropathy had significantly raised concentrations of serum IgA compared to controls (Mann-Whitney U test, P = 0.001) and increased concentrations of conglutinin-binding IgA immune complexes (P = 0.024). No differences in the median concentrations of IgG and IgM anti-IgA antibodies were found between the patients and the controls. In serum samples from healthy controls there was a significant positive correlation between IgM anti-IgAp and IgA immune complex concentrations (P = 0.05), which contrasted with the finding of an inverse correlation between IgM anti-IgAp and IgA immune complex concentrations in patients with IgA nephropathy (P less than 0.05). In addition, the concentrations of conglutinin binding IgM immune complexes in serum were found to correlate with the concentration of IgM anti-IgAp (0.010 less than P less than 0.025), IgM anti-IgA1, and IgM anti-IgA2 (P much less than 0.005 for both) in patients with IgA nephropathy but not in controls. IgM anti-IgA antibodies may be important in augmenting the clearance of IgA immune complexes from the serum of patients with IgA nephropathy.
The measurement of relative antibody affinity by ELISA using thiocyanate elution.
A variation of the standard ELISA assay was used to determine the relative affinities of six murine monoclonal anti-dinitrophenol (DNP) antibodies for DNP-bovine serum albumin (DNP-BSA). The procedure involved exposing replicate wells containing antibody bound to antigen to increasing concentrations of the chaotropic thiocyanate ion. Resistance to thiocyanate elution was utilized as a measure of affinity and an index (affinity index) representing a 50% reduction in initial absorbance was used to rank the anti-DNP antibodies in order of increasing affinity. For comparison, the affinity constants of the six monoclonals were determined by equilibrium dialysis with 3H-epsilon-DNP-L-lysine as antigen. A significant correlation (P less than 0.02) was observed between the ranking orders obtained using the two methods, thereby demonstrating the applicability of the elution technique for the measurement of relative antibody affinity.
Growth factor production by a human megakaryocytic tumor cell line.
A recently described human megakaryocytic tumor cell line was analyzed for the presence of growth factor activity and was found to produce large quantities of transforming growth factor beta-like (TGF-beta) and basic fibroblast growth factor-like (bFGF) activities. Growth factor activities were identified using a radioreceptor assay for the TGF-beta-like activity, a heparin-binding assay for the b-FGF-like activity, and a demonstration of distinct biological activities for each type of factor. Tumor poly-A+ RNA revealed strong signals when probed with complementary DNA corresponding to bovine basic FGF and human TGF-beta and weak signals when probed with cDNA corresponding to epidermal growth factor (EGF) and TGF-alpha. The levels of EGF and TGF-alpha produced in the tumor line were too low to be detected by radioreceptor assays. Relative levels of messenger RNA encoding each of the growth factors reflected the relative levels of each of the respective factors tested. These data represent the first definitive identification of FGF-like activities in megakaryocytic-like cell lines. Interestingly, the line displayed little activity similar to platelet-derived growth factor (PDGF) when assayed either biochemically or by poly-A+ RNA analysis.
Anti-IgA antibodies in IgA-deficient children.
IgG and IgM isotype antibodies to polyclonal human IgA, myeloma IgA1, and myeloma IgA2 were estimated in 38 IgA-deficient children aged between 0.9 and 15 years. All children had IgM anti-IgA antibodies. IgG antibodies against either polyclonal IgA, IgA1, or IgA2 were present in 63% of the IgA-deficient children. IgG anti-IgA antibodies were detected against all three antigens in 8 of 11 severely IgA-deficient children and in 7 of 27 partially IgA-deficient children, but in only 1 of 23 healthy adult controls. The proportion of children with IgG anti-IgA antibodies was significantly greater in the severely IgA-deficient group in comparison with the partially IgA-deficient group and the adult controls (chi-square test, P less than 0.01 and P less than 0.005, respectively). There was a strong correlation within each IgG subclass between antibody responses toward each of the three IgA antigens. Twenty-four children were followed over a period ranging from 0.9 to 11 years (mean, 2.3 years). Three children who were initially IgG anti-IgA antibody negative became antibody positive and three who were antibody positive became antibody negative. Five children with severe IgA deficiency remained severely IgA deficient and IgG antibodies to IgA persisted in all five at follow-up. The presence of IgG anti-IgA antibodies did not influence the normalization of serum IgA at follow-up in 14 of 19 children who were initially partially IgA deficient.
Discontinuous polyacrylamide gradient agarose gels resolve a wide range of restriction fragments and optimize the efficiency of nucleic acid transfer.
A vertical electrophoresis procedure utilizing a discontinuous polyacrylamide gradient agarose gel was developed to resolve DNA fragments ranging in size from over 50 kb to less than 300 bp in length. The gel consisted of a polyacrylamide plug at the base of the gel followed by a gradient of agarose ranging from 0.3 to 0.9%. Restriction fragments migrated shorter distances than in a comparable polyacrylamide-0.3% agarose gel, and small fragments were retained. Southern transfer of DNA fragments from the gradient gel onto nitrocellulose was more efficient than transfer of fragments using a nongradient gel.
Immunocytochemical localization of angiotensin II immunoreactivity and demonstration of angiotensin II binding in the rat ovary.
The cellular localization of angiotensin II immunoreactivity and the presence of angiotensin II binding in rat ovaries were studied. Angiotensin II immunohistochemical staining was demonstrated throughout the corpora lutea of gonadotropin-stimulated immature rats and pseudopregnant adult rats, as well as in some stromal and thecal cells surrounding large antral follicles. No immunostaining was observed in granulosa cells of preantral or antral rat follicles or in ovaries from unstimulated immature rats. With in vitro autoradiography, specific, saralasin-suppressible 125I-angiotensin II binding was demonstrated in normal cycling rat ovaries: diestrus greater than proestrus greater than estrus. The combined findings of angiotensin II immunostaining in ovarian follicles and corpora lutea and of cycle-related angiotensin II binding support the hypothesis of a functional role for the ovarian renin-angiotensin system.
Long-term exposure of plaque to zinc citrate.
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The effect of long-term use of a dentifrice containing zinc citrate and a non-ionic agent on the oral flora.
The effect on the oral ecology of daily use, for seven months, of a dentifrice containing 0.5% (w/w) zinc citrate and a non-ionic agent, i.e., 0.2% (w/w) Triclosan (2,4,4'-trichloro-2'-hydroxydiphenyl ether), has been monitored on 13 adult volunteers. Plaque and saliva were sampled monthly and the bacterial flora analyzed. Twenty-six volunteers used a placebo dentifrice as part of their normal oral hygiene for four months to establish the baseline microbial flora. The volunteers were then split into two equal groups: One group continued to use the placebo dentifrice; the other used the dentifrice containing zinc citrate and Triclosan. There was no evidence that seven months' use of a dentifrice containing 0.5% zinc citrate and 0.2% Triclosan caused shifts in the oral microbial ecology, nor was there any evidence of developing bacterial resistance to Triclosan.
Teratogenic effects of a lipophilic cationic dye rhodamine 123, alone and in combination with 2-deoxyglucose.
An anti-tumor agent, the cationic dye rhodamine 123 (Rh 123), becomes concentrated in mitochondria of certain tissues and inhibits ATP production. Rh 123 was tested for developmental toxicity by i.p. injection into pregnant CD-1 mice daily on gestation days 7-10 (plug = day 1) at doses up to 15 mg/kg/day. Additional mice were given a 500 mg/kg/day dose of 2-deoxy-glucose (2-DOG), an inhibitor of glycolytic ATP generation, alone or with Rh 123. Controls received saline equimolar to the 2-DOG. Prenatal mortality was increased by Rh 123 in combination with 2-DOG, with values of 40%, 43%, or 41% dead or resorbed at Rh 123 doses of 8, 12, or 15 mg/kg/day, respectively. When given alone, neither test agent was associated with a significant increase in prenatal death. Concurrent treatment with Rh 123 and 2-DOG resulted in significant incidences of gross malformations (17% to 20%) and skeletal malformations (9% to 72%). At the two highest Rh 123 doses (12 and 15 mg/kg/day) given with 2-DOG, significant findings included retarded skeletal ossification and variations (up to 83% and 41%, respectively), as well as decreased fetal weight. According to these results, combinations of rhodamine 123 and 2-deoxyglucose administered to the dam during early organogenesis are developmentally toxic to mice.
An inexpensive method of drying multiple agarose gels.
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Estimating the relative avidity of mucosal IgA for antigen.
This report concerns the application of a method to estimate the relative avidity of mucosal IgA for casein and beta-lactoglobulin. The chaotropic ion, thiocyanate, was used to disrupt antigen-antibody binding in an enzyme immunoassay. The resultant proportional decrease in optical density of the enzyme immunoassay was directly related to the proportion of IgA eluted from the solid phase-bound antigen. The relative avidity was expressed as the molarity of KSCN resulting in a particular reduction in optical density. The measurement of avidity, the avidity index, was independent of the concentration of mucosal IgA. For anti-casein IgA the interassay coefficient of variation of the index was 14-18%, and the intra-assay coefficient of variation was 6%. For anti-beta-lactoglobulin IgA the interassay coefficient of variation was 10-13% and the intra-assay coefficient of variation was 6%. The method is simple and free of complicated calculations.
Purification of polymeric immunoglobulin from cell culture supernatants by affinity chromatography using secretory component.
Human secretory component bound covalently to Sepharose 4B has been used as an affinity adsorbent to isolate and purify polymeric immunoglobulin from cell culture supernatants. The method was used to isolate murine IgM isotype anti-trinitrophenol antibody and rat IgM isotype anti-lymphocyte antibody from hybridoma cell culture supernatants. Gel filtration of the eluted antibodies followed by enzyme immunoassay showed that all recovered IgM was of pentameric molecular size. Murine IgA isotype anti-dinitrophenol antibody and murine IgA anti-human rotavirus antibody were isolated from cell culture supernatants of a plasmacytoma and a hybridoma respectively. Most of the IgA recovered following affinity adsorption with secretory component was of greater molecular size than dimer. Murine IgG was not adsorbed by secretory component bound to Sepharose. Eluted antibody retained antigen binding activity. Affinity chromatography using human secretory component bound covalently to a solid phase provides an antigen-independent technique for purification of murine and rat IgA and IgM polymeric immunoglobulin from cell cultures.
Nucleotide sequence of the enterotoxin B gene from Staphylococcus aureus.
The complete nucleotide sequence of the enterotoxin B gene from Staphylococcus aureus, as well as the 5' and 3' flanking regions, was determined. Starting from an ATG initiator codon, an open reading frame encoded the enterotoxin B precursor that consisted of 266 amino acids (Mr, 31,400). The 5' terminal portion of the gene encodes a signal peptide 27 amino acids long. The deduced amino acid sequence matched, with a few exceptions, the published amino acid sequence of enterotoxin B. The structural gene was flanked on the 5' side by a promoter-like sequence and on the 3' side by a palindromic structure followed by a thymine-rich region that resembled a transcription termination signal. Downstream from the entB gene were two overlapping open reading frames corresponding to 134 and 185 amino acids in the opposite orientation. The signal sequence of the enterotoxin B precursor resembled that of other secreted proteins found in other bacteria.
Early induction of secretory immunity in infancy: specific antibody in neonatal breast milk.
Neonatal breast milk from 50 babies aged between 2 and 39 days was studied for the presence of antibody to the cows' milk protein beta lactoglobulin. Specific IgA antibody and specific secretory antibody to beta lactoglobulin were detectable towards the end of the second week of life in milk secreted by neonates fed cows' milk formula. Specific antibody concentrations were independent of total IgA concentrations. Babies receiving little or no cows' milk protein did not produce antibody in neonatal breast milk. Antigen specific mucosal immune responses develop in tissues distant from the site of primary mucosal exposure by the end of the second week of life in term human neonates, suggesting that prophylactic immunisation against enteric or other mucosal pathogens within a few days of birth may provide antibody responses in secretions, which may protect against mucosal infection.