The dynamic change of circulating tumour cells in patients with operable breast cancer before and after chemotherapy based on a multimarker QPCR platform.

BACKGROUND: The possible presence of early tumour dissemination is the rationale behind the use of systemic adjuvant chemotherapy in patients with operable breast cancer. Circulating tumour cells (CTC) in peripheral blood may represent the possible presence of early tumour dissemination. However, relatively few studies were designed to investigate the relationship between the change of CTC status and the efficacy of adjuvant chemotherapy in operable breast cancer patients. METHODS: In a prospective study, we established a multimarker real-time quantitative PCR platform to detect CTC in peripheral blood of breast cancer patients. By using this platform, we detected CTC in peripheral blood of 94 operable breast cancer patients. Control group consisted of 20 patients with benign breast disease and 20 healthy volunteers. For 72 patients who underwent systemic adjuvant chemotherapy, the dynamic CTC status at three different time points (1 day before initiation of chemotherapy, 1 week after three cycles of chemotherapy and 1 week after all cycles of chemotherapy) was observed. RESULTS: Circulating tumour cells were detected in 56% (53 out of 94) of patients with operable breast cancer. The specificity was 95%. Seventy-two patients who received systemic adjuvant chemotherapy were followed up. After three cycles of chemotherapy, 47% (18 out of 38) of patients who were CTC-positive before chemotherapy changed into negative status. In addition, another 5% (2 out of 38) of patients had changed into negative status after all cycles of chemotherapy. CONCLUSION: Systemic adjuvant chemotherapy had a significant impact on CTC status, and this effect could be observed after three cycles of chemotherapy. Circulating tumour cells detection had the potential to be used to evaluate the efficacy of systemic adjuvant chemotherapy immediately after the chemotherapy was finished in operable breast cancer patients.

Pseudomonas aeruginosa transmission is infrequent in New Zealand cystic fibrosis clinics.

Pseudomonas aeruginosa is an important pathogen in cystic fibrosis (CF). Although most patients harbour unique P. aeruginosa isolates, some clinics report patients sharing common strains. The overall importance of person-to-person transmission in P. aeruginosa acquisition and whether routine patient segregation is necessary remains uncertain. The present authors therefore investigated the extent of P. aeruginosa transmission in New Zealand CF clinics. New Zealand's seven major CF centres were assessed, combining epidemiological data with computer-assisted SalI DNA fingerprinting of 496 isolates from 102 patients. One cluster of related isolates was significantly more prevalent in the largest clinic than expected by chance. The seven patients with isolates belonging to this cluster had more contact with each other than the remaining patients attending this centre. No other convincing evidence of transmission was found in any of the other smaller clinics. Three P. aeruginosa strains believed to be transmissible between patients in Australian and British CF clinics are present in New Zealand, but there was no definite evidence they had spread. Pseudomonas aeruginosa transmission is currently infrequent in New Zealand cystic fibrosis clinics. This situation could change rapidly and ongoing surveillance is required. The current results confirm that computer-assisted SalI DNA fingerprinting is ideally suited for such surveillance.

Association between betel quid chewing, periodontal status and periodontal pathogens.

The present investigation examined whether an association exists between betel quid chewing and signs of periodontal disease and determined the prevalence of Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis by polymerase chain reaction. The periodontal status of 34 betel quid chewers and 32 non-betel quid chewers were compared. A significantly higher prevalence of bleeding on probing was found in betel quid chewers than non-chewers among the subjects with higher plaque level, greater gingival inflammation, deeper probing depth or greater attachment loss. Also, the results suggested that betel quid chewers may harbor higher levels of infection with A. actinomycetemcomitans and P. gingivalis than non-betel quid chewers. The association persists after adjusting for severity of the clinical parameters. In conclusion, betel quid chewing was associated with a higher prevalence of bleeding on probing where higher clinical levels of disease existed, and with a likelihood of subgingival infection with A. actinomycetemcomitans and P. gingivalis.

Effects of areca nut extracts on the functions of human neutrophils in vitro.

Aqueous extracts of ripe areca nut without husk (ripe ANE) and fresh and tender areca nut with husk (tender ANE) were examined for their effects on the defensive functions of human neutrophils. Exposure of peripheral blood neutrophils to ripe ANE and tender ANE inhibited their bactericidal activity against oral pathogens, including Actinobacillus actinomycetemcomitans and Streptococcus mutans, in a dose-dependent manner. At the concentrations tested, ripe and tender ANEs did not significantly affect the viability of neutrophils as verified by their ability to exclude trypan blue dye. However, both ANEs inhibited the production of bactericidal superoxide anion by neutrophils as measured by cytochrome c reduction. Moreover, the ripe ANE inhibited neutrophils more effectively than did tender ANE. Arecoline, a major alkaloid of areca nut, only exhibited an inhibitory effect on the functions of neutrophils when high concentrations were used. Therefore, arecoline could not be used to explain the inhibitory effects observed for ANEs. In conclusion, our results demonstrated that ripe and tender ANEs reduced the antibacterial activity and the superoxide anion production of neutrophils. This effect may contribute to a less efficient elimination of bacteria from the periodontal environment. Inhibition of the antimicrobial functions of neutrophils may alter the microbial ecology of the oral cavity, and this may be one possible mechanism by which areca nut compromises the oral health of users of areca nut products.

A new method for protein domain recognition.

A fuzzy cluster method is presented to recognize protein domains. This algorithm can identify domains globally. A protein structure set was used to test the algorithm. Among 219 proteins, 66.7% yielded results that agreed with the reference definitions, 30.6% showed minor differences, and only 2.7% (six proteins) showed major differences with the reference. The new method is more than 20 times fast than previous algorithms.

Guided tissue regeneration with and without demineralized freeze-dried bone allografts for maxillary Class II furca invasions of rapidly progressive periodontitis.

BACKGROUND: Guided tissue regeneration (GTR) using an expanded polytetrafluorethylene (ePTFE) membrane is an established treatment modality for periodontal disease. This study was designed to compare the effects of ePTFE membranes with and without demineralized, freeze-dried bone allografts (DFDBA) for treating maxillary class II buccal furca invasions of rapidly progressive periodonitis. METHODS: Seven patients with pairs of maxillary class II buccal furca invasions comprised the study group. The clinical parameters investigated were probing depth, probing attachment level and marginal tissue recession. One defect from each pair of teeth was randomly selected for the ePTFE membrane and DFDBA group and the other tooth defect received ePTFE membrane treatment only. During the operation, horizontal probing depths at the buccal furcation areas were measured. The membrane was removed 6 weeks after insertion. All measurements were repeated 1 year later at surgical re-entry of the buccal furcation. The Wilcoxon ranked sum test was used to test the significance of the difference between the groups 1 year after treatment. RESULTS: In the ePTFE membrane and DFDBA group, the mean probing depth reduction was 2.1 +/- 0.8 mm. The probing attachment gain was 2.6 +/- 1.0 mm and the bone fill was 3.1 +/- 1.7 mm. There was no statistically significant difference between the groups for these parameters. The marginal tissue recession was reduced 0.4 +/- 0.7 mm in ePTFE membrane and DFDBA group but increased 0.9 +/- 0.6 mm in ePTFE membrane only group. This difference was statistically significant (p = 0.016). CONCLUSIONS: There was no difference in probing depth reduction, probing attachment gain or bone fill between the two treatment modalities for treating maxillary class II buccal furca invasion of rapidly progressive periodontitis. Marginal tissue recession can be significantly reduced with the treatment of combined ePTFE membrane and DFDBA.

Emergency center categorization standards.

The SAEM EC Categorization Task Force was developed in response to the 1994 Macy Foundation's recommendation that emergency medicine (EM) organizations "should revise the classification of emergency departments ... to reflect the level of care available in emergency departments, and indicate whether or not facilities are adequate and whether appropriately qualified and credentialed emergency physicians are available 24 hours a day." By holding Level 1 emergency centers (ECs) to objective standards based on the quality of care delivered as well as administrative, research, and educational efforts, SAEM hopes to improve patient care. The SAEM EC Categorization Task Force is now beginning the process of reviewing ECs that provide comprehensive emergency care and serve as regional resources for education, research, and administration in EM. This standards document describes relative and critical criteria to be met in order to receive designation as a Level 1 emergency center. Such centers must meet all critical criteria, and be in sufficient compliance with most or all relative criteria, in order to achieve this designation. This process is entirely voluntary. Any EC is eligible for review. Any institution can initiate the review process by applying. Application materials and further information, including the policies and procedures of the SAEM EC Categorization Task Force, are available from SAEM.

Proceedings of the Future of Emergency Medicine Research Conference, Part I: Executive summary.

The five articles presented in this section were written by representatives of the emergency medicine research community during the "Future of Emergency Medicine Research Conference," March 6 and 7, 1997, in Washington DC. Each presentation was balanced with commentary by two conference participants from outside emergency medicine. The discussion of each presentation was opened to scrutiny and analysis by all the conference participants. The participants included representatives from governmental agencies and other clinical specialties with the experience and understanding of specialty research enhancement. The objectives and recommendations in this final summary are the result of considerable insight and discussion from all participants. The specialty of emergency medicine owes a special thanks to those from outside the specialty who volunteered their time and effort to share their wisdom with us. Although the 35 participants represent many points of view, not all potential viewpoints were included. Hence, there may be other actions that need to be taken by organizations and individuals to advance emergency medicine research. It is now the responsibility of each individual emergency physician to carefully consider his or her own role and commitment in the process of advancing emergency medicine research. Our collective will as academic departments and the organized emergency medicine community must reaffirm our belief in the importance of emergency medicine research. Individually and collectively, we will need to dedicate the necessary resources to implement the strategies suggested for enhancing emergency medicine research training extramural funding, national organization support, multicenter research, and new research outcomes.

Molecular dynamics simulation of protein folding with supersecondary structure constraints.

We integrate molecular dynamics simulation methods with a newly developed supersecondary structure prediction method and compute the structure of a protein molecule, crambin. The computed structure is similar to the crystal structure with an rms error of 3.94 A.

Current concept of guided tissue regeneration with non-absorbable membrane.

Guided tissue regeneration has been well established as a treatment modality for periodontal disease. Proper case selection and delicate surgical skills can lead to the predictable success. Additionally, the GTR may also be used to treat marginal tissue recession, peri-implantitis, and palato-gingival grooves. Furthermore, osteopromotion with membrane techniques can be used as a means to provide ridge augmentation in ridge defects, or as an adjunct to implant placements. It does play a very important role in implant dentistry and aesthetic dentistry.

Research directions in emergency medicine.

The goal of emergency medicine is to improve health while preventing and treating disease and illness in patients seeking emergency medical care. Improvements in emergency medical care and the delivery of this care can be achieved through credible and meaningful research efforts. Improved delivery of emergency medical care through research requires careful planning and the wise use of limited resources. To achieve this goal, emergency medicine must provide appropriate training of young investigators and attract support for their work. Promotion of multidisciplinary research teams will help the specialty fulfill its goals. The result will be the improvement of emergency medical care which will benefit not only the patients emergency physicians serve but also, ultimately, the nation's health.

The effect of oral deferoxamine on iron absorption in humans.

Acute iron overdose is a serious cause of morbidity and mortality, however, optimal gastric decontamination procedures in iron overdose are unclear. In order to determine the effectiveness of oral deferoxamine mesylate solution in humans to prevent the absorption of iron in acute exposures, the following prospective case control crossover study was designed. Seven informed adult human volunteers were given an oral dose of 5 mg/kg elemental iron alone in a control phase and again in an experimental phase followed by a single equimolar dose of oral buffered deferoxamine solution. Plasma iron concentrations were determined spectrophotometrically for eight hours following administration of iron alone and following doses of iron with deferoxamine. There was no significant difference in peak iron concentration, time to peak iron concentration or area-under-the-curve between the two groups. Based on our results, equimolar doses of oral deferoxamine do not appear to decrease the absorption of low doses of oral iron in humans.

Guided tissue regeneration in surgically created 3-walled and 2-walled periodontal osseous defects in monkeys.

BACKGROUND: In the previous clinical studies, guided tissue regeneration resulted in periodontal regeneration after treatment of 3-walled intrabony defects. The purpose of the present study was to compare the regenerative potential of 3-walled and 2-walled surgically created periodontal osseous defects in monkeys following placement of a biocompatible, porous polytetrafluorethylene membrane. METHODS: In each of 8 Taiwan monkeys, 2 maxillary and 2 mandibular teeth were selected for experimentation. Using a diamond bur, 3-walled osseous defects were created on the distal of the maxillary cuspid and the mesial of the mandibular second bicuspid of one side. Two-walled (lingual wall and proximal wall) osseous defects were created on the contralateral side. After root planing, teflon membranes were applied to the mandibular test teeth. In the maxilla, all procedures were the same except for the placement of teflon membranes. Two monkeys were sacrificed 3, 6 and 9 months after operation and prepared for histologic and histometric evaluation. Reentries were performed while the other 2 monkeys were terminated 11 months after operation. RESULTS: Histologic evaluation revealed that new connective tissue attachments were found to a greater extent in the 3-walled periodontal osseous defects treated with teflon membranes compared with the non-membrane sites (p = 0.05). More periodontal regeneration was not predictably obtained in the surgically created 2-walled osseous defects when the teflon membranes were used. CONCLUSIONS: For 3-walled periodontal osseous defects, guided tissue regeneration was superior to conventional periodontal flap surgery. For 2-walled defects, new connective tissue attachment could not be predictably achieved.