Endotoxin affinity for orthodontic brackets.

Endotoxin, cell envelope lipopolysaccharide produced by gram-negative bacteria can activate an immune response through a variety of pathways. In addition, it can stimulate bone resorption and reduce the periodontal tissue's healing capacity. Previous studies have documented the affinity of lipopolysaccharide for restorative materials. This study evaluated the affinity of lipopolysaccharide for commercially available orthodontic brackets. Stainless steel, ceramic, plastic, and "gold" brackets were exposed to 10 EU/mm2radiolabeled Porphyromonas gingivalis or Escherichia coli lipolpoysaccharide in water and incubated for 24 hours at 37 degrees C. Brackets were then transferred to fresh lipopolysaccharide-free water and incubated for 24 hours at 37 degrees C to evaluate elution. This elution transfer was continued up to 96 hours total incubation. Lipopolysaccharide adherence and elution levels were calculated after treatment, and elution solutions were evaluated through liquid scintillation spectrometry. Mean initial lipopolysaccharide adherence ranged from 2.42 +/- 0.26 EU/mm2(E. coli, plastic) to 6.75 +/- 0.34 EU/mm2 (P. gingivalis, stainless steel). P. gingivalis lipopolysaccharide adherence was significantly greater than E. coli lipopolysaccharide adherence for all bracket types. Moreover, for each lipopolysaccharide type, stainless steel brackets exhibited significantly greater lipopolysaccharide adherence. Regarding elution, only the P. gingivalis lipopolysaccharide-exposed ceramic and plastic brackets at 24 hours and the stainless steel and ceramic brackets at 48 hours eluted measurable lipopolysaccharide. Results from this study demonstrate that P. gingivalis and E. coli LPS exhibit a high affinity for orthodontic brackets. In vivo, this affinity could affect the concentration of LPS in the gingival sulcus, thereby contributing to inflammation in tissues adjacent to the brackets.

Width/length ratios of normal clinical crowns of the maxillary anterior dentition in man.

The purpose of this investigation was to analyze the clinical crown of the 3 tooth groups of the maxillary anterior sextant of the permanent dentition of normal subjects with respect to (i) width, length and the width/length ratios and (ii) determine if there is a correlation between tooth dimensions or tooth group ratios and subject height. Subjects (> or = 20 y.o.) were recruited for this study if (i) the free gingival margin on the facial surface of teeth in the maxillary sextant was positioned apical to the cervical bulge, (ii) there was no evidence of attachment loss; as determined by lack of a detectable CEJ and (iii) the marginal tissue was knife edged in form, firm in consistency and coral pink in color. Teeth were excluded if (i) there was evidence of gingival alteration, i.e., gingival overgrowth/hyperplasia, inflammation, altered passive eruption, attachment loss, gingival recession or history of periodontal surgery, or (ii) there was evidence or history of incisal edge/proximal tooth alteration as in, i.e., restorative intervention, traumatic injury or occlusal wear into dentin. At least 1 suitable tooth from each tooth group of the maxillary anterior dentition had to be present. A maxillary impression was taken and poured in yellow die stone. The widest mesial-distal portion and the longest apical-coronal portion of the test teeth were measured. Gender, ethnicity and subject height (SH) were recorded for each participant. Due to a limited ethnic diversity only data from the Caucasian group were analyzed. The mean coronal tooth width (mm) of males versus females was CI: 8.59 versus 8.06, LI: 6.59 versus 6.13 and CA: 7.64 versus 07.15. The mean coronal tooth length (mm) of males versus females was CI: 10.19 versus 9.39, LI: 8.70 versus 7.79 and CA: 10.06 versus 8.89. All width and length measures were significantly greater for males than for females. The mean coronal tooth width/length ratios for males versus females was CI: 0.85 versus 0.86, LI: 0.76 versus 0.79 and CA: 0.77 versus 0.81. A comparison between genders of the width/length ratios of the CI and LI were found not to differ, however the CA ratio for females was significantly greater than for males. A statistically significant difference was found to exist between the mean (cm) SH for males versus females: 181.2 versus 164.0. A positive correlation (p < or = 0.0001 to 0.0691) was found to exist between tooth group width/height ratios within genders. No significant correlation was found between any of the tooth dimensions or tooth group ratios and SH. The results of this study indicate that within male and female Caucasians, the mean width/length ratio of the maxillary 3 anterior tooth groups is 0.81. As well, within both genders there is a positive correlation between tooth group width/length ratios. The significance of these findings with respect to periodontal mucogingival plastic surgical procedures is discussed.

Human fatty acid ethyl ester synthase-III gene: genomic organization, nucleotide sequencing and chromosomal localization.

The complete gene for human fatty acid ethyl ester Synthase-III (FAEES-III) was isolated from a human genomic lambda phage library for functional and structural determination. The gene spans approximately 3.3 kb which includes 791 base pairs of the 5' and 124 base pairs of the 3' flanking regions. The gene is comprised of seven exons and is interrupted by six introns. Several transcription regulatory sequences were identified in the promoter region. Primer extension experiments demonstrated the existence of two possible transcription initiation sites at nucleotide -29 and 32 position, 5' to the start of the translation. In addition to a TATA box at position-29 relative to the transcription initiation site and two Spl GGGCGG recognition sequences at nucleotide positions -42 to -37 and -50 to -45, the promoter contains a sequence motif matching the transcription activating factor AP-1. We also found an A + T rich region between nucleotide -505 and -390 which contained twenty-two AAAAT tandem repeats. The gene for FAEES-III was localized to human chromosome 11 by hybridizing the genomic fragment Xh01 to Chinese hamster/human somatic cell hybrid panels. These data extend our knowledge of non-oxidative alcohol metabolism and permit linkage analyses between this pathway and alcohol-related phenotypes.

Co-expression of tissue inhibitor and matrix metalloproteinase in myocardium.

Matrix metalloproteinases (MMP) are present in the latent form in normal myocardium. To examine the stringent balance between MMP and tissue inhibitor of metalloproteinase (TIMP) and to determine whether MMP are secreted simultaneously and in co-ordination with their inhibitors, we analysed MMP and TIMP by immunological, isolation by gel-permeation and affinity chromatography, and enzymatic assays in tissues and extracts. Using antibodies to MMP-1 and TIMP-1, we found strong in situ staining of MMP-1 and TIMP-1 in tissues. The staining was uniform in the endo- and subendomyocardium as well as in the interstitial space. TIMP-1 was present wherever MMP-1 was localized. From the tissue extract, proteins were separated on a gel-filtration column (Sephacryl S-200) and analysed for MMP and TIMP activity by zymography as well as by using succinyl-Gly-Pro-Leu-Gly-Pro-4-amido-7-methyl coumarin (Suc-GPLGP-AMC) as a selective fluorogenic substrate for collagenase. TIMP and MMP were further purified on collagen-Sepharose affinity column. The results indicated that MMP activity was co-eluted with TIMP activity. MMP-1, MMP-2 and TIMP-1 were further analysed by Northern blot for mRNA levels in the heart, skin, lung, liver and kidney. Results suggested co-expression of MMP-1 and TIMP-1 at the transcription level in all tissues. The level of MMP-2 mRNA was specifically higher in the heart tissue, which suggests a role of MMP-2 in the integrity of cardiovascular structure. The study indicated that myocardium as well as other tissue have an endogenous inhibitory system, suggesting that the MMPs activity is co-ordinated by their inhibitors at both the gene and protein levels. Furthermore, MMP and TIMP were co-expressed and were tightly regulated in maintaining the architecture of the interstitial tissue.

A comparison of the effects of first premolar extractions on third molar angulation.

The effect of third molars on the stability of orthodontic treatment has been studied extensively. Yet the effect of orthodontic treatment, particularly premolar extractions, on third molars has not been substantially studied. The purpose of this investigation was to compare the changes in third molar angulation in patients treated with and without extractions. Records of 45 Class I, nonextraction and 33 Class I, first premolar extraction patients were examined. The pretreatment and posttreatment pantographs were digitized, and the angles between the third molar long axes and the occlusal plane were measured. Changes in third molar angulation from pretreatment to posttreatment for the two groups were compared for statistical differences using a Student's t-test. Statistical analysis revealed there were no significant differences in the change in third molar angulation in either group. On average, the maxillary and mandibular third molars showed an improvement in angulation relative to the occlusal plane. The results suggest that factors other than first premolar extractions may influence third molar angulation.

Marked elevation of serum transaminase activity associated with extrahepatic biliary tract disease.

Nine patients with choledocholithiasis or cholelithiasis developed transient elevations of serum glutamic oxalacetic transaminase (SGOT) levels of greater than 600 units. Awareness of such transient biliary disease will prevent an unnecessary evaluation of a primary hepatocellular disorder. In our study, we concluded that 1) The SGOT level rose and fell rapidly within a 24- to 72-hour period. 2) Higher SGOT levels were seen in patients with choledocholithiasis in whom the gallbladder had been removed. 3) In patients with choledocholithiasis a fall in SGOT level did not necessarily mean the stone had passed.

Approach to patients with multiple relapses of antibiotic-associated pseudomembranous colitis.

Twenty-two patients with multiple relapses of antibiotic-associated pseudomembranous colitis underwent a tapering dose of oral vancomycin for 21 days and a pulse dose of vancomycin for 21 days. In follow-up ranging from 2-12 months with a mean of 6 months, all patients have been without recurrence of the antibiotic-associated pseudomembranous colitis.

Abnormal liver-spleen scan associated with hyperviscosity syndrome.

A patient with hyperviscosity syndrome was noted to have an abnormal liver radionuclide scan. Ultrasound and normalization of the liver scan after plasmapheresis confirmed the non-neoplastic nature of the patchy labeling defects. This case suggests a new cause for labeling abnormalities on liver radionuclide scans in patients with a syndrome where liver biopsies would be unusually hazardous. Possible mechanisms for this scintigraphic pattern in the hyperviscosity syndrome are briefly discussed.