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Biomedical subjects

J B Zhang

Publications and source records attributed to J B Zhang.

At least 19 recordsLinked to original sources
PubMed1998

The influence of smoking and race on adult periodontitis and serum IgG2 levels.

Smoking is a known risk factor for developing periodontal diseases, but the risk appears to be greater for white smokers than black smokers. Furthermore, it has been reported that young white subjects have significantly lower levels of serum IgG2 than their non-smoking counterparts while young black adult subjects are generally not affected by smoking. These relationships prompted the hypothesis that adult white subjects, including periodontitis subjects, who smoked would have more attachment loss than adult black subjects and that smoking would be associated with lower serum IgG2 levels in adult white subjects but not in adult black subjects. Smoking status was established from serum cotinine levels determined by radioimmunoassay. Serum IgG subclass levels were determined using radial immunodiffusion. White adult periodontitis (AP) and non-periodontitis (NP) subjects who smoked had greater mean attachment loss per site than their non-smoking counterparts. Furthermore, smoking white AP subjects and their age-matched NP controls had substantially less IgG2 in their serum. In marked contrast, we were unable to detect any increase in periodontal destruction or a significant decrease in serum IgG2 levels in smoking black AP subjects or their age-matched controls. However, IgG1 and IgG4 levels were reduced in smoking black AP subjects. IgG3 was the only subclass in adults that was unaffected by smoking. IgG2 can be a good opsonin and may help control periodontitis-associated bacteria in adults. Even though a cause-and-effect relationship has not been established, the association between a smoking-related decrease in serum IgG2 and an increase in periodontal destruction in white subjects is striking.

Adult↗
PubMed1997

Decision theoretic steering and genetic algorithm optimization: application to stereotactic radiosurgery treatment planning.

Treatment planning for stereotactic radiosurgery and fractionated radiotherapy is currently a labor intensive, operator-dependent process. Many degrees of freedom exist to make rigorous optimization intractable except by computationally intelligent techniques. The quality of a given plan is determined by an aggregate of clinical objectives, most of which are subject to competing tradeoffs. In this work, we present an autonomous scheme that couples decision theoretic guidance with a genetic algorithm for optimization. Ordinal ranking among a population of viable treatment plans is based on a generalized distance metric, which promotes a decreasing hyperfrontier of the efficient solution set. The solution set is driven toward efficiency by the genetic algorithm, which uses the tournament selection mechanism based on the ordinal ranking. Goals and satisficing conditions can be defined to signal the ultimate and the minimum achievement levels in a given objective. A conventionally challenging case in radiosurgery was used to demonstrate the practical utility and the problem-solving power of the decision theoretic genetic algorithm. Treatment plans with one isocenter and four isocenters were derived under the autonomous scheme and compared to the actual treatment plan manually optimized by the expert planner. Quality assessment based on dose-volume histograms and normal tissue complication probabilities suggested that computational optimization could be driven to offer varying degrees of dosimetric improvement over a human-guided optimization effort. Furthermore, it was possible to achieve a high degree of isodose conformity to the target volume in computational optimization by increasing the degree of freedom in the treatment parameters. The time taken to derive an efficient planning solution was comparable and usually shorter than in the manual planning process, and can be scaled down almost linearly with the number of processors. Overall, the autonomous genetic algorithm scheme was found to be powerful and versatile as a computationally intelligent counterpart to human-guided strategies in treatment optimization for stereotactic radiosurgery and radiotherapy.

Algorithms↗
PubMed1997

Tobacco and smoking: environmental factors that modify the host response (immune system) and have an impact on periodontal health.

This review summarizes the current data on the effects of smoking and tobacco on the immune system and its potential impact on periodontal health. Smokers are 2.5-6 times more likely to develop periodontal disease than non-smokers, and there is evidence for a direct correlation between the number of cigarettes smoked and the risk of developing disease. Tobacco users also tend to exhibit increased severity of periodontal disease. Direct correlations between tobacco use and increased attachment loss and pocket depth and reduced bone crest height have been reported. Although the correlation between tobacco use and periodontal disease is quite strong, the role of tobacco in the pathogenesis of periodontal disease is uncertain. Recent studies indicate that one potential mechanism is that tobacco use exacerbates periodontal disease because it alters the immune response to periodontal pathogens. Indeed, smokers exhibit increased numbers of peripheral blood mononuclear phagocytes which appear to be functionally compromised. Inadequate phagocyte activity could reduce the clearance of pathogens from the oral cavity and thereby facilitate the development of periodontal disease. Tobacco-exposed B- and T-lymphocytes exhibit reduced proliferative capacities which could limit the production of protective immunoglobulins against oral pathogens. The risk factors for periodontal disease can be broadly classified as genetic, environmental, host-response factors, and host-related factors such as age. Tobacco, an environmental factor, undermines the host response and may facilitate the development and progression of periodontal disease. This review highlights the inter-relatedness of two of the risk factors associated with periodontal disease.

Alveolar Bone Loss↗
PubMed1997

The effect of smoking on serum IgG2 reactive with Actinobacillus actinomycetemcomitans in early-onset periodontitis patients.

High titers of serum IgG2 reactive with Actinobacillus actinomycetemcomitans are present in early-onset periodontitis (EOP) patients and it appears that anti-A. actinomycetemcomitans may be protective. Smoking is associated with increased periodontal disease severity in generalized early-onset periodontitis (G-EOP) patients, but is not associated with periodontal disease severity in patients with localized juvenile periodontitis (LJP). Furthermore, smoking is associated with reduced serum IgG2 levels in black patients with G-EOP but not in those with LJP. Based on this selective effect of smoking, we hypothesized that smoking would be associated with a reduction of specific IgG2 reactive with A. actinomycetemcomitans in black G-EOP patients but not black LJP patients. In addition, we examined IgG2 responses to carbohydrate antigens from non-periodontal pathogens including Haemophilus influenzae b oligosaccharide antigen (Hib) and the Streptococcus pneumoniae antigen phosphocholine (PC). Smoking status was assessed from serum cotinine levels, and IgG2 specific for A. actinomycetemcomitans, Hib, and PC was assessed by ELISA. Our study revealed that smoking was correlated with a dramatic reduction in serum IgG2 anti-A. actinomycetemcomitans in G-EOP smokers but not in LJP smokers. In contrast, anti-Hib IgG2 and anti-PC IgG2 were not affected in either G-EOP or LJP patients. In short, these results indicate that smoking is associated with a reduction in serum IgG2 anti-A. actinomycetemcomitans in black G-EOP subjects, but IgG2 reactive with other antigens may not be reduced in G-EOP smokers.

Adolescent↗
PubMed1996

Hyper-immunoglobulin G2 production by B cells from patients with localized juvenile periodontitis and its regulation by monocytes.

Localized juvenile periodontitis (LJP) runs in families, and a predisposition to develop disease appears to be inherited in an autosomal dominant fashion. Patients with LJP have elevated levels of serum immunoglobulin G2 (IgG2), and this is most striking in black LJP patients. We hypothesized that the markedly elevated serum IgG2 levels related to LJP status and race may be attributable to a fundamental difference in the response of black LJP leukocytes. To test this possibility, leukocytes from black LJP patients, black non-periodontitis (NP) controls, and white NP controls were cultured with a nonspecific mitogen (pokeweed mitogen) which stimulates immunoglobulin production. The levels of IgG2 produced were measured using an enzyme-linked immunosorbent assay. The results revealed that the serum IgG2 level differences among black LJP patients and white and black NP subjects were reproducible in peripheral blood leukocytes in vitro. Analysis revealed that B cells from the LJP patients appeared to be predisposed to produce high levels of IgG2. Further analysis supported the concept that the high IgG2 responses of B cells from black LJP patients were regulated by monocytes. Replacing the monocytes in cultures from white NP subjects with LJP monocytes from black patients resulted in production of IgG2 at levels that were comparable with those produced by the LJP B cells from black patients. In short, B cells from black LJP patients produce elevated levels of IgG2 in vitro, and at least part of this elevation appears to be attributable to regulation via the LJP monocytes.

Adult↗
PubMed1996

Influence of smoking and race on immunoglobulin G subclass concentrations in early-onset periodontitis patients.

Recent data indicate that smoking is an important risk factor for the development of periodontitis. Smoking is also known to reduce serum immunoglobulin G (IgG) levels. Interestingly, patients with the localized form of early-onset periodontitis (LJP) have elevated levels of serum IgG2, and those who smoke are not clinically different from nonsmoking LJ subjects. In contrast, patients with the generalized form of early-onset periodontitis (G-EOP) who smoke have more extensive destruction than their nonsmoking counterparts. Given the effects of smoking on EOP and the association of IgG2 with less severe disease, we hypothesized that smoking might reduce serum IgG2 and that this might be most apparent in G-EOP. We therefore examined the effects of smoking on serum IgG subclass concentrations in race-matched groups: LJP, G-EOP, and age-matched periodontally healthy controls (NPs). Smoking status was established from serum cotinine levels, and serum IgG subclass concentrations were determined by using radial immunodiffusion. The data indicated that the effects of smoking were remarkably selective with respect to both IgG subclass and race. Smoking did not appear to have any effect on the concentration of IgG1 or IgG3 in either black or white subjects. In contrast, smoking was associated with depressed serum IgG2 concentrations in both white NP and G-EOP subgroups. Serum IgG2 levels in black subjects did not appear to be depressed by smoking, with the single striking exception of the black G-EOP subgroup which also had depressed serum IgG4 levels. The results here confirm that smoking has effects on serum immunoglobulin levels, but the effects were both race and serum IgG subclass specific. Furthermore, the periodontal diagnosis of EOP subjects appeared to be important, as indicated by the fact that IgG2 and IgG4 levels were reduced in smoking black G-EOP subjects whereas the IgG2 and IgG4 levels in black LJP and NP subjects were not reduced by smoking.

Adult↗
PubMed1994

[Effect of panaxadiol saponin (PDS) on phorbol ester induced change of protein kinase C activity in cardiomyocytes].

Partially purified protein kinase C and protein kinase A were separately incubated with various concentrations of PDS (1-1000 micrograms.ml-1) for 10 min in vitro. The results indicate that protein kinase C activity was inhibited in a dose-dependent manner by PDS, but type I and type II protein kinase A were not. In cardiomyocytes preincubated with PDS (250, 500, 1000 micrograms.ml-1) for 10 min, PMA-induced decrease of cytosol protein kinase C activity and increase of membrane protein kinase C activity were greatly inhibited in the same manner. These results suggest that PDS not only inhibited protein kinase C in vitro, but also inhibited activation of protein kinase C in cardiomyocytes.

Animals↗
PubMed1993

Effect of various vehicles on ketoprofen permeation across excised hairless mouse skin.

The effects of glycerides, short-chain alcohols, and their binary vehicles as donor components on the permeation of ketoprofen (KP) across the excised hairless mouse skin were evaluated with the modified LOVEDAY-type diffusion cell. Among single vehicles, Panasate 800 as tricaprylin appeared to be the most favorable lipophilic vehicle, with no toxicity and with a short lag time (0.9 h), and methanol (MeOH) or ethanol (EtOH) as hydrophilic single vehicles showed the highest KP permeation flux (244.1 and 134.1 micrograms/cm2/h, respectively). Furthermore, KP permeation was enhanced remarkably by the combination of EtOH and Panasate 800 compared with each single vehicle as reflected in the decreased lag time and increased flux. The greatest enhancement was observed in the EtOH/Panasate 800 (40/60) binary vehicle (permeation ratio at 24 h, 40.0%; steady-state flux, 314.0 micrograms/cm2/h; lag time, 3.7 h). Further investigations involving stripping studies and KP accumulation within the skin were performed to explain the mechanism of enhancement caused by the above binary vehicle. It was suggested that the mutual enhancement effect of EtOH/Panasate 800 (40/60) binary vehicle is due to decreasing the barrier ability of the stratum corneum by EtOH and the viable skin by Panasate 800.

Alcohols↗
PubMed1993

[Comparison between the effects of (-)- and (+)-gossypol on protein kinase C and protein kinase A].

Protein kinase C(PKC) and protein kinase A(PKA) purified from rat liver were incubated with (-)- and (+)-gossypol. The activity of PKC was significantly inhibited in a concentration-dependent manner by both (-)-gossypol and (+)-gossypol. (-)-gossypol was found to inhibit type I PKA, whereas the inhibitory action of (+)-gossypol for type I PKA was less potent. Both (-)-gossypol and (+)-gossypol showed inhibition for type II PKA only at high concentration. These results suggest that administration of gossypol might impair cellular signal transduction.

Animals↗
PubMed1991

[Synthesis and analgesic activity of analogs of 4-methoxymethyl fentanyl].

In this paper, the synthesis and analgesic activities of some derivatives of N-[1-(2-phenylethyl)-4-methoxymethyl-4-piperidinyl]-N-propionylanilin e (4-methoxymethyl fentanyl) are reported. In mouse hot plate test, most compounds in this series showed strong narcotic analgesic activities but their activities were lower than those of compounds in the series of 4-methoxycarbonyl fentanyl.

Analgesics, Opioid↗
PubMed1991

Effects of gossypol on phorbol ester-calcimycin-induced prostaglandin synthesis by macrophages.

Arachidonic acid metabolism via cyclooxygenase pathway in mouse resident peritoneal macrophages were stimulated by phorbol-12-myristate-13-acetate (PMA), calcimycin and exogenous arachidonic acid, respectively. Racemic, (-) and (+)-gossypol dose-dependently inhibited PMA or calcimycin-induced synthesis of prostacyclin, thromboxane A2 and prostaglandin F2 alpha, but failed to affect arachidonic acid-induced synthesis of prostaglandin. It is suggested that both (-)-gossypol and (+)-gossypol inhibit synthesis of prostaglandin at the level of arachidonic acid release, and the inhibition of prostaglandin synthesis by gossypol might not be the main mode of its antifertility action.

6-Ketoprostaglandin F1 alpha↗
PubMed1989

[Method of optimization of the solvent system for thin layer chromatography].

In this article, we analyzed 81 usual solvents with Fuzzy group analytical method by a computer at first, and selected 20 better solvents for TLC. Then optimized the solvent system for TLC by means of uniform design test and optimization method--simplex method. We also worked out a modified chromatographic optimization function. This systematized method has been shown to be effective and practical in our experiments. It is not only fit to TLC, but also fit to paper chromatography and liquid chromatography. So far, no similar report has been found in the literature.

Chromatography, Thin Layer↗
PubMed1989

Effect of rhodamine 123 and total glycosides from tripterygium wilfordii (GTW) on ultrastructures, survival and fertilizing capacity of human sperm in vitro.

Human sperms were treated with rhodamine 123 or GTW in vitro. Comparisons were made of survival, fertilizing capacity and ultrastructures of sperms which had been exposed to different concentrations and treatment durations of the agents. The results showed that no prominent change could be observed when treated with lower doses. However, at higher concentrations of rhodamine 123, mitochondria were found to be swollen, vacuolated and deranged instead of surrounding the flagellar axoneme in the normal spiral way, and the mitochondrial cristae were broken or had disappeared. In some sperms, cracks at the flagellar axoneme and concave defects in the acrosome were seen. The sperms lost their fertilizing capacity, though some of them were still alive, whereas the sperms treated with GTW showed no morphological damage and maintained their ability to penetrate the hamster egg. Our results suggest that rhodamine 123 is a prospect in the search for an anti-sperm contraceptive.

Animals↗