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Biomedical subjects

D B Drucker

Publications and source records attributed to D B Drucker.

At least 37 records · Page 2Linked to original sources
PubMed1999

Endotoxin in blood and tissue in the sudden infant death syndrome.

Although the explanation for sudden infant death syndrome (SIDS) remains unknown, an increasing body of evidence now exists to suggest a possible role for bacterial toxins in the aetiology, and a number of investigators have considered that endotoxaemia could explain some of the associated features. Following the development of an animal model which confirmed that endotoxaemia could be detected after death, we studied endotoxin levels in blood and tissue samples taken at autopsy from SIDS infants, child controls and adult controls. There were significant correlations between endotoxin levels in blood and the various organs sampled particularly in SIDS cases and child controls, and blood endotoxin levels in SIDS cases were higher in those infants where there was histological evidence of mild to moderate inflammation. However, overall no significant differences were found between endotoxin levels in blood or tissue in the three study groups. Further studies into possible actions or interactions of endotoxin in SIDS are required.

Adult↗
PubMed1999

Preliminary investigation of lethally toxic sera of sudden infant death syndrome victims and neutralisation by commercially available immunoglobulins and adult sera.

The aim of the study was to test the hypotheses (i) that sudden infant death syndrome sera are toxic to 11-day old chick embryos and (ii) that such a toxicity can be counteracted by immunoglobulin or adult sera. Serum samples from 11 SIDS victims and five controls were tested for lethal toxicity in the chick embryo bioassay. Five serum samples were used to challenge chick embryos injected with the following: sudden infant death syndrome serum plus Hank's balanced salt solution; Hank's balanced salt solution alone; sudden infant death syndrome serum plus 3% w/v commercial immunoglobulin; sudden infant death syndrome serum plus 6% w/v immunoglobulin; sudden infant death syndrome serum plus pooled sera of 40 healthy adults. Results obtained revealed that Hank's balanced salt solution, the pooled adult serum and the commercial immunoglobulin were all non-lethal, in the chick embryo test system. By contrast. 10 sudden infant death syndrome victims yielded sera containing lethal levels of toxin(s) compared to 2/5 controls which was statistically significant (P < 0.05, Fischer's exact test). In the tests of sudden infant death syndrome serum plus immunoglobulin or pooled adult serum, the lethality of sudden infant death syndrome serum was abolished in all cases. The reduction in toxicity of individual sudden infant death syndrome serum plus immunoglobulin or pooled adult serum was often statistically significant (P<0.05-P<0.00005, Fischer's exact test). We conclude that lethal levels of toxin are present in sudden infant death syndrome sera and that they can be neutralised by normal immune serum. These results indicate that passive immunisation is a potential treatment to protect babies considered at risk from sudden infant death syndrome.

Adult↗
PubMed1999

Phospholipid analogue distribution in Capnocytophaga.

Polar lipids of nineteen previously characterised culture collection strains of Capnocytophaga were analysed using fast atom bombardment mass spectrometry (FAB MS) in negative mode. All strains examined had a major peak at m/z 241, consistent with the expected presence of the pentadecanoate anion. The most intense higher mass anions, consistent with expected presence of phospholipid molecular species, were as follows: m/z 574, 588, 618 and 662 which are consistent with presence of PE(24:2), PE(25:2), PE(27:1) and PE(30:0) respectively. Other anions putatively identified as phospholipid anions were: m/z 572, 578, 592, 602, 604, 616 and 720 consistent with presence of PE(24:3), PE(24:0), PE(25:0), PE(26:2), PE(26:1), PE(27:2) and OH-PE(33:0). Capnocytophaga isolates share a distinctive phospholipid fingerprint which appears to lack the somewhat higher mass phospholipid analogues observed in related oral bacteria. Within the genus, the profiles obtained showed only quantitative differences which did not correlate with previous studies.

Capnocytophaga↗
PubMed1999

Phospholipid molecular species distribution of some medically important Candida species analysed by fast atom bombardment mass spectroscopy.

The aim of this study was to obtain detailed information on phospholipids (PL) of the medically important Candida species and to determine their possible chemotaxonomic significance. Lipids were extracted from 22 strains representing 8 Candida species and their PL molecular species distributions were determined by Fast Atom Bombardment Mass Spectroscopy (FAB MS) in negative ion mode. Fifteen major lower mass peaks (m/z 221 to 289) were attributable to the expected presence of carboxylate anions and 24 major higher mass peaks (m/z 557 to 837) were attributable to phospholipid anions. Major carboxylate peaks were of the following m/z and identities : 253, C16:1; 255, C16:0; 277, C18:3; 279, C18:2; 281, C18:1; and 283, C18:0. The most abundant peaks consistent with the presence of phospholipid molecular species anions include those of m/z 673, 743, 833, 834 and 836 tentatively identified as phosphatidic acid (PA) (34:1), phosphatidylglycerol (PG) (34:3), phosphtidylinositol (PI) (34:2) and two unknown molecular species. This profile is diagnostic for the genus Candida. Quantitative differences were observed between different Candida species. Thus, polar lipid molecular species distribution in Candida spp. has chemotaxonomic significance, especially so in the case of carboxylate anions.

Candida↗
PubMed1999

Sensitivity of Candida albicans to negative air ion streams.

Negative air ions (NAIs) are known to kill C. albicans; however, their precise mechanism of action is uncertain. Elucidation of this has been hampered by a lack of reproducibility between results obtained by different investigators. The aim of this study was to determine the influence of variation in experimental parameters on the sensitivity of C. albicans to negative air ions and the role of ozone in this process. Ten strains of C. albicans were exposed to NAIs generated at different emitter distances, exposure times, relative humidities and under aerobic and oxygen-free conditions. In further experiments, ozone levels were measured under the same conditions. The effect of NAIs on C. albicans growth was assessed by measuring the area of the zone of inhibition generated around the electrode of the ionizer. There was a significant reduction in area of zone of inhibition with increasing emitter distance (P < 0.05), relative humidity (P < 0.05) or under oxygen-free conditions (P < 0.05). Increases in exposure time resulted in a significant increase in growth inhibition (P < 0.05). Ozone levels increased with increasing exposure times (P < 0.01) but were significantly reduced as emitter distance increased (P < 0.01). When utilized in a nonventilated room, levels of ozone produced did not exceed recognized safety limits. These results (a) demonstrate the importance of careful control of experimental parameters if reproducibility of studies involving NAIs is to be achieved, and (b) highlight the possible role of ozone in the microbicidal effects of NAIs.

Air↗
PubMed1999

Possible potentiation of toxins from Prevotella intermedia, Prevotella nigrescens, and Porphyromonas gingivalis by cotinine.

BACKGROUND: Smoking is a recognized risk factor for the initiation and progression of periodontitis. However, the mechanism by which smoking induces its negative effects on the periodontium is not clear. This study aimed to test the hypothesis that synergy may occur between cotinine and bacterial products isolated from 3 putative periodontopathogens. METHODS: A chick embryo toxin assay was used to investigate bacterial toxins (cell-free extracellular toxins and cell-free cell lysates) from 5 species with and without cotinine. A total of 9 putative periodontopathogens (3 species) and 2 non-oral controls (2 species) were studied. The periodontal species were: Prevotella intermedia (n = 4), Prevotella nigrescens (n = 4), and Porphyromonas gingivalis (n = 1). The control species tested were: Staphylococcus aureus (n = 1) and Escherichia coli (n = 1). RESULTS: The toxicity kill was significantly greater than expected by simple addition alone (P <0.05, Fisher's exact test) between cotinine (800 ng/ml) and 1) the cell-free extracellular toxins of P. nigrescens MH1 and 2) the cell-free cell lysates of P. intermedia MH2. Synergy occurred with cotinine plus the cell-free extracellular toxins in all but 3 periodontal isolates, and the cell-free cell lysates in all but 2 periodontal isolates. Cotinine significantly (P <0.05, Fisher's exact test) enhanced the effects of cell-free extracellular toxins and cell lysates from one control species (E. coli), but not the other (S. aureus). CONCLUSIONS: These findings indicate that synergy in an in vitro assay can occur between cotinine and toxins from putative periodontopathogens. This may be one important mechanism by which smoking increases the severity of periodontitis.

Animals↗
PubMed1999

Effects of tobacco products on the attachment and growth of periodontal ligament fibroblasts.

BACKGROUND: Cigarette smoking is one of the most significant risk factors in the development and further advancement of inflammatory periodontal disease, however, the role of either nicotine or its primary metabolite cotinine in the progression of periodontitis is unclear. This study aimed to investigate the effects of nicotine and cotinine on the attachment and growth of fibroblasts derived from human periodontal ligament (PDL). METHODS: Primary cultures were prepared from the roots of extracted premolar teeth. Cells were used at both low (P3 to P5) and high (P11 to P13) passage. Cell numbers were determined over 14 days using either the 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay or with a Coulter counter. Cultures were exposed to culture medium supplemented with 1) 15% fetal calf serum (FCS) only; 2) 1% FCS only; 3) 1% FCS and nicotine (concentration range 5 ng/ml to 10 mg/ml); or 4) 1% FCS and cotinine (concentration range 0.5 ng/ml to 10 microg/ml). RESULTS: Nicotine significantly (P <0.05, by ANOVA) inhibits attachment and growth of low passage cells at concentrations >1 mg/ml and high passage PDL fibroblasts at concentrations >0.5 mg/ml. Cotinine, at the highest concentration used (10 microg/ml), appeared to inhibit attachment and growth of both low and high passage fibroblasts but this was not statistically significant (P >0.05, by ANOVA). CONCLUSIONS: Tobacco products inhibit attachment and growth of human PDL fibroblasts. This may partly explain the role of these substances in the progression of periodontitis.

Analysis of Variance↗
PubMed1998

Photosensitization of Staphylococcus aureus with malachite green isothiocyanate: inactivation efficiency and spectroscopic analysis.

The potential of malachite green isothiocyanate as a photosensitizer for the inactivation of bacteria has been evaluated. Samples of Staphylococcus aureus are treated with the dye and exposed to continuous-wave red light from a filtered xenon lamp. Reduction in cell viability is seen to increase with radiation dose, whilst non-photosensitized samples are largely unaffected with exposure. The mechanism of photosensitization and the subsequent inactivation is addressed. UV-Vis and Fourier-transform infrared absorption spectrometry have been applied to this biological system, revealing the rapid hydrolysis of the isothiocyanate group of the dye and the transition to the colourless carbinol base when in solution. On binding to Staphylococcus aureus via a complexation mechanism, the dye is seen to be stabilized in its cationic form. Involvement of the excited triplet state of the photosensitizer is suggested and identification of reduced dye photoproducts is made following irradiation.

Absorption↗
PubMed1998

Phospholipids of Fusobacterium spp.

The aim of this study was to analyse individual polar lipid analogues, within each lipid family present, of fusobacteria using fast atom bombardment mass spectrometry (FAB-MS). Polar lipid extracts were prepared, washed and dried. Samples, dispersed in a matrix of m-nitrobenzyl alcohol, were analysed by negative ion FAB-MS using xenon as the reagent gas. Major anion peaks observed in the low mass region of mass/charge (m/z), 211, 221, 225, 227, 239, 241, 249, 251, 253, 255, 273, 277, 279, 281, 289 and 291, were consistent with the presence of C13:1, C14:3, C14:1, C14:0, C15:1, C15:0, C16:3, C16:2, C16:1, C16:0, unknown, C18:3, C18:2, C18:1, unknown and C19:3 carboxylate anions. In the high mass region, major anion peaks observed with m/z 644, 646, 648, 660, 662, 672, 673, 674, 686, 688, 689, 690, 698, 700, 701, 703, 714, 716, 717 and 719 were consistent with the presence of phosphatidylethanolamine (PE) (29:2), PE (29:1), PE (29:0), PE (30:1), PE (30:0), PE (31:2), first isotope of PE (31:2), PE (31:1), PE (32:2), PE (32:1), first isotope peak of PE (32:1), PE (30:0), PE (33:3), PE (33:2), phosphatidylglycerol (PG) (31:3), PG (31:2), PE (34:2), PE (34:1), PG (32:2) and PG (32:1). We conclude that FAB-MS can provide data on individual analogues of PE and PG from Fusobacterium spp. not readily obtained by other means. Furthermore, the phospholipid profile is diagnostic for the genus.

Fusobacterium↗
PubMed1998

Phospholipid molecular species distribution of Porphyromonas asaccharolytica ATCC 25260T: effects of temperature, culture age and pH.

The aim of this study was to determine the extent to which phospholipid molecular species profiles are affected by different environmental factors in Porphyromonas asaccharolytica ATCC 25260T. Phospholipids were analysed by Fast Atom Bombardment Mass Spectrometry (FAB-MS) in negative-ion mode. Under standard growth conditions (37 degrees C, pH 7.0, 48 h), the most intense high mass anions were m/z 653 and 662. The latter is consistent with the expected presence of PE (30:0). The only changes in profiles were quantitative. These were compared using the Pearson Coefficient of Linear Correlation. The r-values for initial pH comparisons ranged from 0.82 (pH 7.0 vs pH 6.0) to 1.00 (pH 5.0 vs pH 8.0), for incubation period, from 0.86 (48 vs 72 h) to 0.97 (96 vs 168 h), and for temperature, from 0.57 (40 vs 37 degrees C) to 0.96 (37 vs 36 degrees C). Differences were also seen when plates were incubated in anaerobe jars as opposed to an anaerobic work station (r = 0.75). It is concluded that it is essential to standardize growth parameters, and to use an anaerobe jar or an anaerobe work station, but not both.

Hydrogen-Ion Concentration↗
PubMed1998

Phospholipid molecular species distribution of oral Prevotella corporis clinical isolates.

The aim of this study was to determine the distribution of phospholipid molecular species within Prevotella corporis of oral origin. Phospholipids of fresh clinical isolates were extracted and analysed by fast atom bombardment mass spectrometry (FAB-MS) in negative-ion mode. The major monocarboxylate anion peaks, with putative identification, observed for Prevotella corporis were m/z 241, C(15:0); 255, C(16:0); 269, C(17:1); 277, C(18:3); 279, C(18:2); 281, C(18:1). In the high mass region, major anion peaks putatively identified as individual phospholipid (PL) molecular species of Prevotella corporis were of m/z 677, PG(29:1); 691, PG(30:1); 705, PG(31:1); 706, first isotope peak of PG(31:1); and 707, PG(31:0). Related species have a different distribution of PL analogues. Separation of extracted lipid families by TLC confirmed that phosphatidylethanolamine (PE) and phosphatidylglycerol (PG) are the major polar lipids (PLs) in Prevotella corporis. Thus Prevotella corporis has a unique combination of phospholipid analogues of chemosystematic significance.

Chromatography, Thin Layer↗
PubMed1998

Polar lipids of Aspergillus fumigatus, A. niger, A. nidulans, A. flavus and A. terreus.

Little is known of the phospholipid composition of Aspergillus species. The aim of this study was to determine individual phospholipid analogues in Aspergillus. Twenty-nine clinical and environmental isolates from five Aspergillus species were analysed. Fast atom bombardment mass spectrometric data were considered in two ranges, m/z 190-500 and m/z 500-1000, to facilitate the recognition of major fatty acyl groups and phospholipids. Quantitative comparison of major anions in both m/z ranges was undertaken. Confirmation of major phospholipid anions from eight representative isolates was achieved by tandem mass spectrometry. The major phospholipid families were phosphatidic acid (PA), phosphatidylethanolamine (PE), phosphatidylinositol (PI), and phosphatidylserine (PS). Anions were detected consistent with the presence of specific phospholipid moieties, such as palmitoyl-linolenoyl phosphatidic acid, palmitoyl-oleoylphosphatidylethenolamine, oleoyl-linoleoyl-phophatidylserine and palmitoyl-linoleoyl-phosphatidylinositol. It appears that there is some commonality of sn1 or sn2 fatty acyl substituents, frequently C18:2 at sn1 accompanied by C16:0 at sn2, with differing molecular weights being attributable to analogues with differing head groups. Differences in certain phospholipids (e.g. minor peak with m/z 933) were detected between A. fumigatus, A. nidulans and other species examined which could have diagnostic value.

Aspergillus↗
PubMed1997

The role of gastric and postgastric sites in glucose-conditioned flavor preferences in rats.

Two experiments examined the role of gastric and postgastric contributions in the development of flavor preferences in rats. During training trials, food-deprived rats consumed, on alternate days, a cue flavor paired with glucose infusions and another flavor paired with water infusions. Preferences were assessed in choice tests between the two cue flavors without infusions. The first experiment compared preferences conditioned to a flavor paired with intraduodenal (ID) glucose infusions to those paired with intragastric (IG) infusions. ID glucose-conditioned preferences were as strong as that of IG glucose. The second experiment examined whether the actions of glucose in the stomach alone were sufficient to condition flavor preferences. Glucose infusions were restricted to the stomach with an inflated pyloric cuff and then removed at the end of 30-min training sessions before the cuff was deflated. Rats trained with this procedure did not develop a reliable flavor preference. Flavor preferences were obtained, however, when the cuff was inflated for 30 min after the end of the daily training sessions, or when the cuff was inflated during the training sessions but then deflated without removing the infused glucose. Both of these procedures allowed at least some of the infused glucose to empty into the intestine. Taken together, the results indicate that information from the stomach is neither necessary nor sufficient to produce glucose-conditioned flavor preferences. Such preferences are reinforced by the intestinal and/or postabsorptive actions of glucose.

Animals↗
PubMed1997

The detection of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia using an ELISA in an adolescent population with early periodontitis.

The aim of the study was to compare the occurrence and levels of A. actinomycetemcomitans, P. gingivalis, and P. intermedia in the subgingival plaque from sites with and without early periodontitis in adolescents using an ELISA. 47, 15- to 16-year-old adolescents (39 Indo-Pakistani, 8 white Caucasian) were examined for clinical attachment level, probing depth, supragingival plaque, subgingival calculus and bleeding on probing on the mesio-buccal and disto-buccal aspects of the 1st molars and the incisors. Based on the clinical data, 2 sites per subject were selected for subgingival plaque sampling 3 weeks later: in 32 subjects with loss of attachment > or = 1 mm, a diseased site (D) and a healthy comparison control site (C) were sampled; in 15 subjects in whom loss of attachment had not yet developed, 1 of the upper molar sites was selected, called the at-risk site (R), together with a C site. The presence and levels of A. actinomycetemcomitans, P. gingivalis, and P. intermedia were determined using an ELISA. The loss of attachment subgroup had significantly more pockets > or = 4 mm, subgingival calculus and bleeding on probing (p < 0.05). Significantly more of the D than C sites had P. gingivalis both at detectable and at measurable levels (p < 0.05). In subjects who had no loss in clinical attachment levels, fewer sampled sites harboured any of the suspected periodontopathogens investigated, and no significant differences were found between the R or C sites (p > 0.05). Although there was a significantly higher prevalence and extent of loss of attachment > or = 1 mm in the Indo-Pakistani subjects compared with the Caucasians (p < 0.05), no differences could be identified in the distribution of the bacteria. It is concluded that monitoring of the subgingival plaque may be useful in studies of early periodontitis in adolescents, and the role of P. gingivalis needs to be elucidated in prospective longitudinal investigations.

Adolescent↗
PubMed1997

Possible lethal enhancement of toxins from putative periodontopathogens by nicotine: implications for periodontal disease.

AIM: To test the hypothesis that lethal synergy in the chick embryo model may occur between nicotine and bacterial products (cell-free extracellular toxins and cell lysates) of five putative periodontopathogens. METHODS: The lethality of cell-free extracellular toxins and cell lysates of five periodontal species was assessed with or without nicotine in the chick embryo assay system. Ten putative periodontopathogens (five species) were studied: Prevotella intermedia (n = 5), Porphyromonas gingivalis (n = 1), Porphyromonas asaccharolytica (n = 1), Fusobacterium nucleatum (n = 2), and Fusobacterium necrophorum (n = 1). RESULTS: Simultaneous testing of cell-free extracellular toxins from isolates W50, PS2, PS3, PS4, and PS5 and nicotine resulted in a percentage kill significantly greater than expected (Fisher's Exact test). Simultaneous testing of cell lysates from isolates W50, PS2, and PS5 and nicotine resulted in a percentage kill significantly greater than expected (Fisher's Exact test). CONCLUSIONS: Lethal synergy in the chick embryo model may occur between nicotine and toxins from putative periodontopathogens (both cell-free extracellular toxins and cell lysates). This may be an important mechanism by which smoking increases the severity of periodontal disease.

Animals↗
PubMed1996

Phospholipid profiles in the oral yeast Candida.

Individual molecular species of phospholipids can now be readily detected using fast atom-bombardment mass spectrometry (FAB MS). The aim was to obtain detailed information on individual molecular species of Candida phospholipids using FAB MS. Lipids were extracted from Candida isolates and prepared for FAB MS analysis in negative-ion mode. Each isolate yielded several hundred anion peaks. The major anion peaks consistent with the presence of phospholipids included those of mass/charge (m/z) 836, 743, 715, 744 and 834 tentatively identified as phosphatidylethanolamine PE(43:5), phosphatidylglycerol PG(34:3), PG(32:3), PE(36:1) and PE(43:5). Major peaks consistent with the presence of carboxylate anions were of m/z 241, 253, 255, 277, 279, 281, 283, and 307 putatively identified as C15:0, C16:1, C18:3, C18:2, C18:1, C18:0 and C20:2 which also support the putative identifications of phospholipids. Such phospholipid profiles differ from those published for other microorganisms analysed by FAB MS. Quantitative differences were observed between different candidal species. Candida albicans may be readily differentiated from C. glabrata on the basis of its carboxylate anions. Within species, there are quantitative differences in phospholipid profiles. Thus, Candida has a unique combination of phospholipid analogues with potential chemosystematic significance.

Anions↗
PubMed1996

Associations of endodontic symptoms and signs with particular combinations of specific bacteria.

Significant associations have been reported between (a) specific bacterial species isolated from root canals and (b) between individual bacterial species and endodontic symptoms and signs. The prime objective of this study was to determine whether particular combinations of specific bacteria are associated with individual endodontic symptoms and signs. Seventy root canals were investigated microbiologically taking care to maintain the viability of obligate anaerobes, which accounted for 64% of the total species isolated, including Peptostreptococcus micros, Prevotella melaninogenica, Prevotella oralis, Eubacterium aerofaciens, Eubacterium lentum, Fusobacterium nucleatum, Prevotella buccae and Prevotella intermedia. Significant associations were found between individual clinical features and the following pairs of species: (a) pain (37 cases) and Peptostreptococcus spp./Prevotella spp., Peptostreptococcus spp./Prevotella melaninogenica, Pstr. micros/Prev. melaninogenica (all P < 0.01); (b) swelling (23 cases) and Pstr. micros/Prevotella spp. (P < 0.01); (c) 'Wet' canal (57 cases) and Prevotella spp./Eubacterium spp. (P < 0.01), Peptostreptococcus spp./Eubacterium spp. (P < 0.05). Thus data from this investigation suggests that statistically significant associations exist between individual endodontic symptoms and signs and particular combinations of specific bacteria.

Adolescent↗