Limb-salvage treatment of malignant tumors of the limbs

The aim of this study was to explore the clinical efficacy of limb-salvage therapy for malignant bone tumors of the limbs using two surgical methods. This investigation presents a retrospective study of malignant bone tumors of the limbs in 42 patients. Participants were divided into two groups: group A of 25 patients who were treated with artificial prosthesis replacement, and group B of 17 patients treated with bone inactivation. By collection of clinical data, the survival rate, surgical complications, quality of life, pain relief and postoperative limb function following artificial prosthesis replacement and tumor inactivation were comprehensively evaluated in patients with malignant bone tumors of the limbs. Group A had significantly higher Karnofsky quality of life scores compared to group B after six months (P=0.027). The Enneking scores of limb functions in group A were significantly higher than those of group B (P=0.022). In group A the postoperative limb function score was good and excellent in 92% and in group B in 64.7%. There were significantly more postoperative complications in group B compared with group A (P=0.027), but no significant difference in the recurrence rate in the two group (P=0.976). The study results can provide reference for surgical treatment of the patients with malignant bone tumors.

Effect of branched chain amino acids on perioperative temperature, glucose level and fat metabolism in patients with gastrointestinal tumors

This study aimed to investigate the effect of branched chain amino acids (BCCAs) on perioperative temperature, glucose and fat metabolism in patients with gastrointestinal tumors. Fifty-six patients undergoing gastrointestinal tumor surgery were included in the study and randomly divided into two groups of 28 patients each: an experimental and a control group. During surgery, the experimental group received 5.64mL·Kg-1·h-1(4KJ·Kg-1·h-1) of BCCAs intravenously, through an infusion pump, and the control group received an equal volume of NaCl 0.9%. Vital signs were continuously monitored during the operation. Nasopharynx temperature levels of glucose, insulin, free fatty acid and ketone bodies in the blood were determined 30 min before anesthesia (t 0), after anesthesia and before surgery (t 1), 30 min after the start of surgery (t 2), 2 h after start of surgery (t 3) and 1 h after the end of surgery (T4). Patients’ shivering intensity (Wrench grading) and pain degree [Visual analogue scale (VAS)]) were estimated 1 h after the endotracheal tube was removed. Nasopharynx temperature was decreased (p less than 0.05) in both groups after anesthesia induction, while 1 h after the tube was removed it was higher in the experimental group than the control group (p less than 0.05); compared with pre-surgery values, blood glucose levels were increased during surgery in both groups, but the experimental group had a lower increasing trend compared to the control group, though without statistical significance (p>0.05). Insulin levels were significantly different between the two groups at all time-points during surgery (p less than 0.05). However, the rising trend of the experimental group was more dramatic during the period from t 0 to t 3. One hour after surgery (t 4), the insulin levels varied, but still at higher levels than pre-surgery, with a significant difference (p less than 0.05); levels of free fatty acids had a downward trend in both groups, and levels in the experimental group continued to decline until 1 h after surgery. Patients who received branched chain amino acids had less temperature decrease during surgery. Moreover, blood glucose levels were not increased, which limits fat mobilization and leads to production of ketone bodies, reduces the shivering and its intensity after surgery.

Effect of dexmedetomidine on stress reactions and cellular immune function of patients in perioperative period following radial resection for rectal carcinoma

The study aimed to assess the effects and the further mechanism of action of dexmedetomidine with regard to stress reactions and cellular immune function of patients during the perioperative period following radical resection for rectal carcinoma. A total of 36 patients with rectal carcinoma were selected for radical resection under general anesthesia. The patients were divided into two groups, namely an experimental and a control group. In the experimental group (dexmedetomidine group) 1 μg/ kg/bw dexmedetomidine was injected intravenously 10 min prior to the induction of general anesthesia, and then infusion was carried out at a rate of 0.2 μg·kg-1·h-1 for 30 min prior to the end of surgery. With regard to the control group, the same amount of normal saline (NS) was infused with the same method as the experimental group. Controlled intravenous analgesia was conducted following surgery to all of the patients. Regarding the effect of dexmedetomidine on the reaction of stress, a decrease of VAS scores was noted in the experimental group following extubation compared with the control group (P less than 0.05). Furthermore, a significant decrease in the consumption of morphine in the first 24 h was observed that was accompanied by a decrease of plasma cortisol levels at 6 and 24 h following surgery compared with the control group. The levels of IFN-γ/IL-10 in the experimental group were lower than those of the control group (P less than 0.05). The percentages of CD8+ and CD4+/CD8+ cells in the experimental group were increased compared with those of the control group (P less than 0.05). By infusing dexmedetomidine continuously, stress reactions during the perioperative period were significantly decreased, whereas the analgesic effects of opioid were increased.

Relationship between genetic variants of ACE2 gene and circulating levels of ACE2 and its metabolites

WHAT IS KNOWN

Angiotensin-converting enzyme 2 (ACE2) plays an important role in the development of essential hypertension (EH). Genetic factors remarkably influence circulating ACE2 level.

OBJECTIVE

Because heritability had remarkable effects on circulating ACE2, we designed this study to shed light on whether circulating levels of ACE2, angiotensin-(1-7) and angiotensin-(1-9) were linked to single nucleotide polymorphisms (SNPs) and haplotypes in ACE2 gene.

METHODS

A total of 213 patients with newly diagnosed mild to moderate EH were enrolled in the present study. Four ACE2 tag SNPs (rs2074192, rs4646171, rs4646155 and rs2106809) were genotyped, and major haplotypes consisting of these 4 SNPs were reconstructed for all subjects. Circulating levels of ACE2, angiotensin-(1-7) and angiotensin-(1-9) were measured using enzyme-linked immunosorbent assay.

RESULTS

In female subjects, linear regression analysis suggested that rare alleles of ACE2 rs2074192 and rs2106809 were associated with reduced circulating angiotensin-(1-7) levels (P=.007 and P=.006, respectively). ACE2 haplotype CAGC was associated with elevated circulating angiotensin-(1-7) levels (P=.03) whereas TAGT was associated with reduced circulating angiotensin-(1-7) levels in females (P<.001). Univariate linear regression analysis revealed that circulating ACE2 levels were positively associated with systolic blood pressure (P=.02), mean arterial pressure (P=.02) and serum creatinine (P<.001) in females whereas circulating ACE2 levels were positively associated with age (P<.001) and serum creatinine (P<.001) in males.

WHAT IS NEW AND CONCLUSION

ACE2 SNPs and haplotypes are associated with circulating angiotensin-(1-7) levels. ACE2 genetic variants may be the determinants of circulating angiotensin-(1-7) levels in hypertensive females.

Impact of ACE2 gene polymorphism on antihypertensive efficacy of ACE inhibitors

Angiotensin-converting enzyme 2 (ACE2), a newly discovered member of renin-angiotensin-aldosterone system, counterbalances the actions of angiotensin-converting enzyme. The objective of our study was to assess the association between rs2106809 polymorphism in ACE2 gene and the blood pressure response to ACE inhibitors in untreated hypertensive patients. After a 2-week, double-blind placebo run-in period, either benazepril or imidapril was administered for 6 weeks to 497 patients with mild to moderate essential hypertension. The achieved changes in BP were analyzed for their association with genotypes at ACE2 gene loci. In female hypertensive patients, the genotype frequency of ACE2 rs2106809 was 36.7%, 45.2% and 18.1% for CC, CT and TT genotypes, respectively. After 6 weeks of treatment, the reductions in diastolic blood pressure were significantly greater in female patients carrying the CC or CT genotype compared with those carrying the TT genotype (9.62±6.83 or 10.2±7.2 versus 6.81±6.31 mm Hg, respectively; P=0.045, analysis of variance (ANOVA)). Moreover, the reductions in mean arterial pressure were significantly greater in female patients carrying the CC or CT genotype compared with those carrying the TT genotype (12.1±7.5 or 12.0±7.9 versus 8.38±6.83 mm Hg, respectively; P=0.035, ANOVA). In male hypertensive patients, the genotype frequency of ACE2 rs2106809 was 58.1% and 41.9% for C and T genotypes, respectively. However, no association could be observed in males. We conclude that ACE2 rs2106809 is an important predictive factor of the response to antihypertensive treatment with ACE inhibitors in Chinese female hypertensive patients.

Peri-implant conditions and their relationship with periodontal conditions in Chinese patients: a cross-sectional study

OBJECTIVES

To analyze the relationships between peri-implant conditions and periodontal conditions in Chinese patients with dental implants in place for at least 1 year.

MATERIAL AND METHODS

Seventy-six patients (mean age, 41 ± 10 years; range, 21-69 years) who received placement of 120 dental implants (Straumann(®) ), (mean 1.6 implants per subject; range, 1-5 implants per subject) after a mean period of 25 months (range, 12-66 months) responded to recall. Clinical examinations were performed around the implants and natural teeth. Periapical radiographs were taken by the long cone technique for implants, and radiographic bone level (BL) was measured. Comparisons of the peri-implant conditions were performed between the patients with different periodontal conditions by t-test and chi-square test. The relative risk of periodontal condition as a risk factor for peri-implant conditions was analyzed by logistic regression.

RESULTS

Subjects who presented with ≥5% sites with probing depth (PD) ≥ 4 mm and ≥30% sites with bleeding on probing (BoP) in the dentition showed significantly poorer peri-implant conditions (58% vs. 18% subjects who had maximum modified gingival index (mGI) 2 or 3, P = 0.003; 94% vs. 62% subjects who had maximum PD ≥ 4 mm, P = 0.008; 100% vs. 79% subjects who had BoP, P = 0.044; mean PD 3.36 ± 0.66 vs. 2.75 ± 0.66 mm, P = 0.002; and sites% with BoP 68 ± 23% vs. 36 ± 31%, P < 0.001), as compared with those who had <5% sites with PD ≥ 4 mm and <30% sites with BoP on the remaining teeth. The relative risk for subjects with the more severe and extensive periodontal conditions compared to those with better periodontal conditions to have PD ≥ 5 mm with BoP at peri-implant sites was 23.3 (P = 0.003, 95% CI, 2.8-192.3.

CONCLUSIONS

The peri-implant conditions were significantly related to the periodontal conditions around the remaining natural teeth, which implies that control of periodontal disease is essential for successful implant treatment.

Expression profile of macrophage migration-inhibitory factor in human gingiva and reconstituted human gingival epithelia stimulated by Porphyromonas gingivalis lipopolysaccharide

BACKGROUND AND OBJECTIVE

Macrophage migration-inhibitory factor (MIF) plays crucial roles in the recruitment and activation of macrophages as well as in helping to kill bacteria. This study investigated the expression profile of MIF in human gingiva under different periodontal conditions and its expression patterns induced by Porphyromonas gingivalis lipopolysaccharide (LPS) in gingival epithelia.

MATERIAL AND METHODS

Gingival tissue samples were collected from deep pockets and clinically healthy sites of 22 nonsmoking subjects with chronic periodontitis. The expression of MIF mRNA and protein was evaluated using real-time PCR and immunohistochemistry, respectively. The in vitro study analyzed the effects of P. gingivalis LPS on the expression of MIF in a reconstituted human gingival epithelia (RHGE) model.

RESULTS

In gingival epithelia, MIF protein was diffusely expressed from the basal layer to the granular and spinous layers; whereas, in the underlying connective tissues, MIF was observed around the dilated blood vessels in the deep-pocket tissues. A significantly lower level of expression of MIF mRNA and an increased level of expression of MIF protein were found in deep-pocket tissues compared with clinically healthy tissues. Expression of MIF mRNA in the RHGE model was significantly down-regulated by P. gingivalis LPS.

CONCLUSION

The present study suggests that MIF expression may be related to periodontal conditions and that its expression profile could be modulated by P. gingivalis LPS. MIF may play a role in periodontal pathogenesis.

Nuclear factor-κB and p38 mitogen-activated protein kinase signaling pathways are critically involved in Porphyromonas gingivalis lipopolysaccharide induction of lipopolysaccharide-binding protein expression in human oral keratinocytes

Lipopolysaccharide (LPS) -binding protein (LBP) plays a crucial role in innate host response to bacterial challenge. Porphyromonas gingivalis is a keystone pathogen in periodontal disease and the shift of P. gingivalis LPS lipid A structure from penta-acylated (LPS(1690)) to tetra-acylated (LPS(1435/1449)) isoform may significantly contribute to periodontal pathogenesis. We recently demonstrated that LBP is expressed in human gingiva and contributes to periodontal homeostasis. Furthermore, different isoforms of P. gingivalis LPS differently modulate the immuno-inflammatory response, and P. gingivalis LPS(1690) induces LBP expression in human oral keratinocytes (HOKs). This study further examined the signaling mechanisms of P. gingivalis LPS(1690) -induced and Escherichia coli LPS-induced LBP expression in HOKs. Both P. gingivalis LPS(1690) and E. coli LPS were potent inducers of LBP expression in HOKs. The former activated phosphorylation of IκBα, p65, p38 mitogen-activated protein kinase (MAPK) and stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK), whereas the latter phosphorylated IκBα, p38 MAPK and SAPK/JNK. A nuclear translocation of NF-κB transcription factor was confirmed upon stimulation by both forms of LPS. Further blocking assay showed that P. gingivalis LPS(1690) induction of LBP was through NF-κB and p38 MPAK pathways, whereas E. coli LPS-induced LBP expression was mediated by NF-κB, p38 MPAK and JNK pathways. This study demonstrates that NF-κB and p38 MAPK signaling pathways are involved in P. gingivalis LPS(1690) induction of LBP expression in HOKs. The current findings could enhance the understanding of the molecular mechanisms of innate defense in maintenance of periodontal homeostasis.

Pseudomonas aeruginosa lipopolysaccharide inhibits Candida albicans hyphae formation and alters gene expression during biofilm development

Elucidation of bacterial and fungal interactions in multispecies biofilms will have major impacts on understanding the pathophysiology of infections. The objectives of this study were to (i) evaluate the effect of Pseudomonas aeruginosa lipopolysaccharide (LPS) on Candida albicans hyphal development and transcriptional regulation, (ii) investigate protein expression during biofilm formation, and (iii) propose likely molecular mechanisms for these interactions. The effect of LPS on C. albicans biofilms was assessed by XTT-reduction and growth curve assays, light microscopy, scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM). Changes in candidal hypha-specific genes (HSGs) and transcription factor EFG1 expression were assessed by real-time polymerase chain reaction and two-dimensional gel electrophoresis, respectively. Proteome changes were examined by mass spectrometry. Both metabolic activities and growth rates of LPS-treated C. albicans biofilms were significantly lower (P < 0.05). There were higher proportions of budding yeasts in test biofilms compared with the controls. SEM and CLSM further confirmed these data. Significantly upregulated HSGs (at 48 h) and EFG1 (up to 48 h) were noted in the test biofilms (P < 0.05) but cAMP levels remained unaffected. Proteomic analysis showed suppression of candidal septicolysin-like protein, potential reductase-flavodoxin fragment, serine hydroxymethyltransferase, hypothetical proteins Cao19.10301(ATP7), CaO19.4716(GDH1), CaO19.11135(PGK1), CaO19.9877(HNT1) by P. aeruginosa LPS. Our data imply that bacterial LPS inhibit C. albicans biofilm formation and hyphal development. The P. aeruginosa LPS likely target glycolysis-associated mechanisms during candidal filamentation.

Periodontal therapy decreases serum levels of adipocyte fatty acid-binding protein in systemically healthy subjects: a pilot clinical trial

BACKGROUND AND OBJECTIVE

Adipocyte fatty acid-binding protein (A-FABP) is expressed in adipocytes, macrophages and microvascular endothelial cells, and it plays a central role in inflammation, atherosclerosis and metabolic responses. This pilot study investigated the effect of nonsurgical periodontal therapy on the serum levels of A-FABP in subjects with chronic periodontitis.

MATERIAL AND METHODS

A pilot clinical trial was conducted in 24 otherwise healthy Chinese subjects with moderate to severe chronic periodontitis. The treatment group (n = 12) received nonsurgical periodontal therapy immediately, whereas in the control group (n = 12) the treatment was delayed for 3 months. The serum levels of A-FABP were measured by ELISAs. Other inflammatory and endothelial biomarkers and periodontal conditions were evaluated at baseline and at the 3-month follow-up appointment.

RESULTS

A-FABP levels decreased significantly in the treatment group compared with the control group (treatment effect: -1.7 ng/mL; 95% confidence interval: -2.8 to -0.6; p = 0.003). The treatment also significantly improved periodontal conditions but had no significant effect on other biomarkers. In the multivariable regression model, the change in the percentage of sites with detectable plaque was significantly associated with the change in the level of A-FABP (beta: 0.04, 95% confidence interval: 0.01-0.06, p = 0.004).

CONCLUSION

Within the limitations of this pilot study, the current findings suggest that treatment of periodontitis may significantly decrease the serum levels of A-FABP. Further longitudinal study with a large sample size is warranted to confirm this finding and elaborate the relevant clinical implications.

Microbial chemical signaling: a current perspective

Communication among microorganisms is mediated through quorum sensing. The latter is defined as cell-density linked, coordinated gene expression in microbial populations as a response to threshold signal concentrations followed by induction of a synchronized population response. This phenomenon is used by a variety of microbes to optimize their survival in a constantly challenging, dynamic milieu, by correlating individual cellular functions to community-based requirements. The synthesis, secretion, and perception of quorum-sensing molecules and their target response play a pivotal role in quorum sensing and are tightly controlled by complex, multilayered and interconnected signal transduction pathways that regulate diverse cellular functions. Quorum sensing exemplifies interactive social behavior innate to the microbial world that controls features such as, virulence, biofilm maturation, antibiotic resistance, swarming motility, and conjugal plasmid transfer. Over the past two decades, studies have been performed to rationalize bacterial cell-to-cell communication mediated by structurally and functionally diverse small molecules. This review describes the theoretical aspects of cellular and quorum-sensing mechanisms that affect microbial physiology and pathobiology.

Rhodiola algida improves chemotherapy-induced oral mucositis in breast cancer patients

OBJECTIVE

Oral ulcerative mucositis, a common adverse effect due to mainstream cytotoxic drugs, limits the nutritional intake of cancer patients. Rhodiola algida is widely used in traditional Chinese medicine to stimulate the immune system. The aim of this study is to investigate the effect of this herbal extract on healthy human lymphocytes in vitro, the homeostasis of cancer patients and the healing time of oral ulcers.

METHOD

The constituents of Rhodiola algida were analyzed by RP-HPLC. Lymphocytes isolated from 462 healthy subjects were treated with 100 ug/ml Rhodiola algida for 48 h. The activity of the cells was measured by cell proliferation reagent and ATP assay. The level of various cytokines and mRNA content of lymphocytes were determined. Rhodiola algida demonstrated no toxicity in animals, which had been orally fed with 1 mg/ml Rhodiola algida for 30 days. 130 breast cancer patients from Huaxi Hospital of Sichuan University were recruited between 2006 and 2007. They received four cycles of 5-fluorouracil, epirubicin and cyclophosphamide after modified total mastectomy. These patients were randomly assigned to test and control groups. Rhodiola algida mixture was consumed by the test group for 14 consecutive days after each cycle of chemotherapy. All patients were given 0.2% chlorohexidine mouth wash to be used every day. Complete blood counts, liver and renal function tests together with the number and size of oral ulcerations were analyzed after each cycle. Weight loss, complaints of nausea or vomiting and degree of pain were noted.

RESULTS

The optimal concentration of Rhodiola algida favored the proliferation of lymphocytes. The levels of IL-2, IL-4, granulocyte-macrophage colony-stimulating factor and the mRNA content of these cytokines were also enhanced. White blood cell (WBC) levels returned to normal range in both groups 1 week after every cycle of chemotherapy. WBC count increased faster in patients using Rhodiola algida; they presented with smaller and fewer oral ulcers. There were no liver or renal complications observed in any patients.

CONCLUSION

Rhodiola algida increases immunity of patients who are receiving chemotherapy post mastectomy and decreases the quantity of oral ulcers. Thus Rhodiola algida has the potential to be used concurrently with chemotherapy to alleviate the occurrence of oral ulcers.

Bacterial lipopolysaccharides variably modulate in vitro biofilm formation of Candida species

The objective of this study was to evaluate the effect of the bacterial endotoxin LPS on Candida biofilm formation in vitro. The effect of the LPS of Pseudomonas aeruginosa, Klebsiella pneumoniae, Serratia marcescens and Salmonella typhimurium on six different species of Candida, comprising Candida albicans ATCC 90028, Candida glabrata ATCC 90030, Candida krusei ATCC 6258, Candida tropicalis ATCC 13803, Candida parapsilosis ATCC 22019 and Candida dubliniensis MYA 646, was studied using a standard biofilm assay. The metabolic activity of in vitro Candida biofilms treated with LPS at 90 min, 24 h and 48 h was quantified by XTT reduction assay. Viable biofilm-forming cells were qualitatively analysed using confocal laser scanning microscopy (CLSM), while scanning electron microscopy (SEM) was employed to visualize the biofilm structure. Initially, adhesion of C. albicans was significantly stimulated by Pseudomonas and Klebsiella LPS. A significant inhibition of Candida adhesion was noted for the following combinations: C. glabrata with Pseudomonas LPS, C. tropicalis with Serratia LPS, and C. glabrata, C. parapsilosis or C. dubliniensis with Salmonella LPS (P<0.05). After 24 h of incubation, a significant stimulation of initial colonization was noted for the following combinations: C. albicans/C. glabrata with Klebsiella LPS, C. glabrata/C. tropicalis/C. krusei with Salmonella LPS. In contrast, a significant inhibition of biofilm formation was observed in C. glabrata/C. dubliniensis/C. krusei with Pseudomonas LPS, C. krusei with Serratia LPS, C. dubliniensis with Klebsiella LPS and C. parapsilosis/C. dubliniensis /C. krusei with Salmonella LPS (P<0.05). On further incubation for 48 h, a significant enhancement of biofilm maturation was noted for the following combinations: C. glabrata/C. tropicalis with Serratia LPS, C. dubliniensis with Klebsiella LPS and C. glabrata with Salmonella LPS, and a significant retardation was noted for C. parapsilosis/C. dubliniensis/C. krusei with Pseudomonas LPS, C. tropicalis with Serratia LPS, C. glabrata/C. parapsilosis/C. dubliniensis with Klebsiella LPS and C. dubliniensis with Salmonella LPS (P<0.05). These findings were confirmed by SEM and CLSM analyses. In general, the inhibition of the biofilm development of LPS-treated Candida spp. was accompanied by a scanty architecture with a reduced numbers of cells compared with the profuse and densely colonized control biofilms. These data are indicative that bacterial LPSs modulate in vitro Candida biofilm formation in a species-specific and time-dependent manner. The clinical and the biological relevance of these findings have yet to be explored.

Pseudomonas aeruginosa inhibits in-vitro Candida biofilm development

Background

Elucidation of the communal behavior of microbes in mixed species biofilms may have a major impact on understanding infectious diseases and for the therapeutics. Although, the structure and the properties of monospecies biofilms and their role in disease have been extensively studied during the last decade, the interactions within mixed biofilms consisting of bacteria and fungi such as Candida spp. have not been illustrated in depth. Hence, the aim of this study was to evaluate the interspecies interactions of Pseudomonas aeruginosa and six different species of Candida comprising C. albicans, C. glabrata, C. krusei, C. tropicalis, C. parapsilosis, and C. dubliniensis in dual species biofilm development.

Results

A significant reduction in colony forming units (CFU) of C. parapsilosis (90 min), C. albicans and C. tropicalis (90 min, 24 h and 48 h), C. dubliniensis and C. glabrata, (24 h and 48 h) was noted when co-cultured with P. aeruginosa in comparison to their monospecies counterparts (P < 0.05). A simultaneous significant reduction in P. aeruginosa numbers grown with C. albicans (90 min and 48 h), C. krusei (90 min, 24 h and 48 h),C. glabrata, (24 h and 48 h), and an elevation of P. aeruginosa numbers co-cultured with C. tropicalis (48 h) was noted (P < 0.05). When data from all Candida spp. and P. aeruginosa were pooled, highly significant mutual inhibition of biofilm formation was noted (Candida P < 0.001, P. aeruginosa P < 0.01). Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM) analyses confirmed scanty architecture in dual species biofilm in spite of dense colonization in monospecies counterparts.

Conclusions

P. aeruginosa and Candida in a dual species environment mutually suppress biofilm development, both quantitatively and qualitatively. These findings provide a foundation to clarify the molecular basis of bacterial-fungal interactions, and to understand the pathobiology of mixed bacterial-fungal infections.

Architectural analysis, viability assessment and growth kinetics of Candida albicans and Candida glabrata biofilms

The human fungal pathogen Candida is able to form biofilms in almost all the medical devices in current use. Indeed, biofilm formation is a major virulence attribute of microorganisms and account for a majority of human infections. Therefore, understanding processes appertaining to biofilm development is an important prerequisite for devising new strategies to prevent or eradicate biofilm-related infections. In the present study we used an array of both conventional and novel analytical tools to obtain a comprehensive view of Candida biofilm development. Enumeration of colony forming units, colorimetric (XTT) assay, Scanning Electron Microscopy (SEM) and novel Confocal Laser Scanning Microscopy (CLSM) coupled with COMSTAT software analyses were utilised to evaluate growth kinetics; architecture and viability of biofilms of a reference (ATCC) and a clinical strain each of two Candida species, C. albicans and C. glabrata. Biofilm growth kinetics on a polystyrene substrate was evaluated from the initial adhesion step (1.5 h) up to 72 h. These analyses revealed substantial inter- and intra-species differences in temporal organisation of Candida biofilm architecture, spatiality and cellular viability, while reaching maturity within a period of 48 h, on a polystyrene substrate. There were substantial differences in the growth kinetics upon methodology, although general trend seemed to be the same. Detailed architectural analysis provided by COMSTAT software corroborated the SEM and CSLM views. These analyses may provide a strong foundation for down stream molecular work of fungal biofilms.

Escherichia coli and its lipopolysaccharide modulate in vitro Candida biofilm formation

Demystification of microbial behaviour in mixed biofilms could have a major impact on our understanding of infectious diseases. The objectives of this study were to evaluate in vitro the interactions of six different Candida species and a Gram-negative coliform, Escherichia coli, in dual-species biofilms, and to assess the effect of E. coli LPS on Candida biofilm formation. A single isolate of E. coli ATCC 25922 and six different species of Candida, Candida albicans ATCC 90028, Candida glabrata ATCC 90030, Candida krusei ATCC 6258, Candida tropicalis ATCC 13803, Candida parapsilosis ATCC 22019 and Candida dubliniensis MYA-646, were studied using a standard biofilm assay. Each Candida species was co-cultured with E. coli on a polystyrene surface and biofilm formation was quantified by a c.f.u. assay. The biofilm was then analysed by Live/Dead staining and fluorescence microscopy (confocal laser-scanning microscopy, CLSM), whilst scanning electron microscopy (SEM) was employed to visualize the biofilm architecture. The effect of E. coli LPS on Candida biofilm cell activity at defined time intervals was assessed with an XTT reduction assay. A significant quantitative reduction in c.f.u. counts of C. tropicalis (after 90 min), C. parapsilosis (after 90 min and 24 h), C. krusei (after 24 h) and C. dubliniensis (after 24 and 48 h) was noted on incubation with E. coli in comparison with their monospecies biofilm counterparts (P <0.05). On the other hand, a simultaneous and significant reduction in E. coli cell numbers occurred on co-culture with C. albicans (after 90 min), and an elevation of E. coli cell numbers followed co-culture with C. tropicalis (after 24 h) and C. dubliniensis (after 24 h and 48 h) (P <0.05). All quantitative findings were confirmed by SEM and CLSM analyses. By SEM observation, dual-species biofilms demonstrated scanty architecture with reduced visible cell counts at all stages of biofilm development, despite profuse growth and dense colonization in their single-species counterparts. Significantly elevated metabolic activity, as assessed by XTT readings, was observed in E. coli LPS-treated C. tropicalis and C. parapsilosis biofilms (after 48 h), whilst this had the opposite effect for C. dubliniensis (after 24 h) (P <0.05). These data indicate that E. coli and Candida species in a mixed-species environment mutually modulate biofilm development, both quantitatively and qualitatively, and that E. coli LPS appears to be a key component in mediating these outcomes.

Exploring the oral bacterial flora: current status and future directions

OBJECTIVE

The oral cavity forms an indispensable part of the human microbiome, for its unique and diverse microflora distributed within various niches. While majority of these organisms exhibit commensalism, shifts in bacterial community dynamics cause pathological changes within oral cavity and distant sites. The aim of this review was to appraise the current and emerging methods of detecting bacteria of the oral cavity paying particular attention to the cultivation independent methods.

DESIGN

Literature pertaining to cultivation based and cultivation independent methods of oral bacterial identification was reviewed.

METHODS

The specific advantages and disadvantages of cultivation based, microscopic, immunological and metagenomic identification methods were appraised.

RESULTS

Because of their fastidious and exacting growth requirements, cultivation based studies grossly underestimate the extent of bacterial diversity in these polymicrobial infections. Culture independent methods deemed more sensitive in identifying difficult to culture and novel bacterial species.

CONCLUSION

Apart from characterizing potentially novel bacterial species, the nucleic acid sequence data analyzed using various bioinformatics protocols have revealed that there are in excess of 700 bacterial species inhabiting the mouth. Moreover, the latest pyrosequencing based methods have further broadened the extent of bacterial diversity in oral niches.

Molecular mechanisms of interaction between the neuroprotective substance riluzole and GABA(A)-receptors

The antiepileptic drug riluzole is used as a therapeutic agent in amyotrophic lateral sclerosis due to its neuroprotective effects. Besides presynaptic inhibition of GABAergic and preferentially glutamatergic transmission, it also potentiates postsynaptic GABA(A)-receptor function. We investigated the postsynaptic effects of riluzole on GABA(A)-receptor channels by use of the patch-clamp technique. Recombinant alpha1beta2gamma(2s) and alpha1beta2 GABA(A) receptors were expressed in HEK 293 cells by transient transfection. Pulses of GABA were applied in combination with different concentrations of riluzole to whole cell or outside-out patches with either alpha1beta2gamma(2s) or alpha1beta2 GABA(A)-receptor channels. Co-application of riluzole led to a slight decrease of absolute peak current amplitudes and steady-state currents in prolonged presence of GABA at saturating concentrations. In the presence of riluzole, enhancement of current amplitudes was observed with lower concentrations of GABA at alpha1beta2gamma(2s) receptors and to a lower extent also at alpha1beta2 receptors. Thus, the potentiating effect of riluzole was shown to be not abolished in the absence of the gamma(2s)-subunit. A further prominent effect of riluzole was a highly significant acceleration of the time course of current decay, most probably pointing to an open-channel block-like mechanism of action. As both receptor subtypes were affected similarly by the block, it could be concluded that the respective binding sites should be assumed within a region of high sequence homology like it is given for the channel-lining M2 domain of GABA(A)-receptor subunits. In conclusion, three different molecular mechanisms of interaction of the neuroprotective compound riluzole were observed at two different subtypes of GABA(A) receptor channels. The results further point to the impact of the inhibitory as well as the excitatory synaptic activity as a pharmacological target to counteract chronic excitotoxicity and reveal molecular mechanisms of action of the only one neuroprotective drug in current clinical use in patients suffering from amyotrophic lateral sclerosis.

Phospholipase, proteinase and haemolytic activities of Candida albicans isolated from oral cavities of patients with type 2 diabetes mellitus

The aim of this study was to biotype and characterize phospholipase, proteinase and haemolytic activities of oral Candida albicans isolates from 210 Chinese patients with type 2 diabetes mellitus (DM) and 210 age- and sex-matched healthy controls. Seventy-six and 50 C. albicans isolates were obtained from type 2 DM patients and controls, respectively, using the oral rinse technique. The isolates were characterized with a biotyping system based on enzyme profiles, carbohydrate assimilation patterns and boric acid resistance of the yeasts, and the isolates were further tested for in vitro phospholipase, proteinase and haemolytic activities. The major biotypes of C. albicans isolates from the type 2 DM and control groups were A1R (42.1 %) and J1R (36.0 %), respectively. Significantly higher proteinase and haemolytic activities were found in the isolates from the type 2 DM group (P<0.05). Proteinase activity was higher in isolates from patients with > or =10 years of DM history than those with <10 years (P<0.05). Haemolytic activity was significantly higher in isolates from female DM patients than in those from male counterparts (P<0.05). These data provide evidence of increased extracellular enzyme activity in Candida isolates taken from DM patients.

IL-1alpha, IL-1ra and IL-8 are differentially induced by Candida in experimental oral candidiasis

OBJECTIVE

To investigate the expression of interleukin-1alpha (IL-1alpha), IL-1ra and IL-8 by the oral epithelium challenged by various Candida species.

MATERIALS AND METHODS

In vitro candidiasis was induced by C. albicans wild type SC5314, its EFG1, CPH1 and secretory aspartyl proteinase (SAP) mutants and, ATCC isolates of C. albicans, C. tropicalis and C. dubliniensis using a reconstituted human oral epithelium (RHOE) model. IL-1alpha, IL-1ra and IL-8 levels in culture media were quantified by an enzyme-linked immunosorbent assay at 12, 24 and 48 h. Fungal invasion and IL-1ra expression in RHOE were detected by periodic acid-Schiff staining and immunohistochemistry.

RESULTS

Overall, the invasive Candida induced relatively higher levels of IL-1alpha, IL-1ra and IL-8 in the culture media than the noninvasive isolates. IL-1alpha and IL-1ra levels induced by Candida with hyphal invasion were significantly higher (P < 0.05) than those induced by the isolates without hyphal invasion at 12, 24 and 48 h. Candida albicans SC5314 induced IL-1ra expression in RHOE at 12 and 24 h but not at 48 h consistent with its hyphal invasion; while the noninvasive mutants and non-albicans Candida induced IL-1ra expression at 48 h.

CONCLUSIONS

The cytokine expression profiles in experimental oral candidiasis may be associated with the invasive potential of Candida.

Periodontitis and premature death: a 16-year longitudinal study in a Swedish urban population

BACKGROUND AND OBJECTIVE

Growing experimental evidence implicates chronic inflammation/infection due to periodontal diseases as a risk factor for death. The objective was to evaluate the role of periodontitis in premature death in a prospective study.

METHODS

The causes of death in 3273 randomly-selected subjects, aged 30-40 years, from 1985 to 2001 were registered. At baseline, 1676 individuals underwent a clinical oral examination (Group A) and 1597 did not (Group B). Mortality and causes of death from 1985 to 2001 were recorded according to ICD-9-10.

RESULTS

In Groups A (clinically examined group) and B, a total of 110 subjects had died: 40 subjects in Group A, and 70 in Group B. In Group A significant differences were present at baseline between survivors and persons who later died, with respect to dental plaque, calculus, gingival inflammation and number of missing molars in subjects with periodontitis (p < 0.001). The multiple logistic regression analysis results of the relationship between being dead (dependent variable) and several independent variables identified periodontitis with any missing molars as a principal independent predictor of death.

CONCLUSIONS

Young individuals with periodontitis and missing molars seem to be at increased risk for premature death by life-threatening diseases, such as neoplasms, and diseases of the circulatory and digestive systems.

A survey on the preference for continuing professional dental education amongst general dental practitioners who attended the 26th Asia Pacific Dental Congress

AIMS

To identify the subjects of interest and to examine the modes as well as means of study for continuing professional dental education amongst general dental practitioners who attended the 26th Asia Pacific Dental Congress, 28 May-1 June 2004, Hong Kong.

METHODS

A total of 381 general dental practitioners as the registered conference delegates from Hong Kong, Mainland China and other Asia-Pacific regions were randomly selected for the present survey. The survey was conducted through face-to-face interviews by a group of practising dentists in Hong Kong.

RESULTS

Overall, orthodontics and prosthodontics were the most popular subjects for clinical degree programmes, whilst oral implantology and cosmetic dentistry were the highly preferred subjects for continuing education courses. Concerning the preferred mode of study for degree programmes, the part-time study mode was chosen by 68.3% of the participating dentists. A didactic teaching approach was preferred by most of the participants (81.7%) for postgraduate study. The majority of the interviewees (76.5%) were interested in a proposed clinical degree programme to be offered jointly by The University of Hong Kong and a leading university in the Mainland. Overall, there was no marked difference in the preference for continuing dental education amongst the respondents from Hong Kong, Mainland China and other Asia-Pacific regions.

CONCLUSIONS

The present survey shows the currently preferred specialty areas and subjects for continuing professional dental education amongst the general dental practitioners who attended the 26th Asia Pacific Dental Congress, with didactic teaching as the most preferred mode of study on a part-time basis.

Human histologic and electromicroscopic analysis with synthetic peptide enhanced hydroxyapatite in the maxillary sinus elevation procedure: a case report

Elevation of the sinus floor to augment the alveolar process to place implants is an effective treatment. The traditional use of autologous bone implies a secondary donor site and the related morbidity, and, hence, is not readily accepted by many patients. The new graft material, synthetic peptide enhanced hydroxyapatite (PepGen P-15 Flow, Ceramed Dental, Lakewood, CO, DENTSPLY Int.,York, PA), shows the ease in use and ability to generate new bone growth in the sinus elevation procedure. Histologic and electromicroscopic analysis was performed on the new bone formed after the application.

The prevalence of dentine hypersensitivity in a hospital clinic population in Hong Kong

OBJECTIVES

Dentine hypersensitivity is a common clinical finding with a wide variation in prevalence values. The aim of this study was to establish the prevalence of dentine hypersensitivity and to examine some associated aetiological factors in a cross-sectional study of patients visiting the Periodontology and Oral Hygiene Clinic at Prince Phillip Dental Hospital, Hong Kong over a three-week period.

METHODS

226 patients were examined over a three-week period using a triple syringe to administer a blast of cold air to confirm the diagnosis of dentine hypersensitivity. Additional factors such as smoking habits, initiating stimuli, gingival recession and cervical tooth surface loss were noted.

RESULTS

153 patients were diagnosed as having dentine hypersensitivity, giving a prevalence figure of 67.7%. The commonest teeth affected were the lower incisors and the commonest initiating factor was cold drinks.

CONCLUSIONS

The prevalence of dentine hypersensitivity in a hospital periodontology clinic population in Hong Kong was 67.7%.

The effects of tobacco use on oral health

OBJECTIVE

To review the effects of tobacco use on oral health, with particular emphasis on the effects of periodontal diseases, dental implant failures, and risk of development of oral cancers and precancers.

DATA SOURCES

Medline literature search (1977-2002).

STUDY SELECTION

Key words for the literature search were 'tobacco smoking', 'periodontal disease', 'dental implant', and 'oral cancers and precancers'.

DATA EXTRACTION

Evidence-based literature review.

DATA SYNTHESIS

The prevalence and severity of periodontal diseases in their various forms are higher among smokers than among non-smokers. The success of dental implant treatments is significantly influenced by addiction to tobacco smoking. The failure rate of implant osseointegration is considerably higher among smokers, and maintenance of oral hygiene around the implants and risk of peri-implantitis are adversely affected by smoking. The risks of developing oral cancers and precancers are greater in smokers. Betel nut chewing and smokeless tobacco produce similar risk to cancer incidence as tobacco smoking. Cessation of tobacco use has a beneficial effect on halting the progression of periodontal diseases and on the outcome of periodontal therapy.

CONCLUSIONS

Medical and dental teams should be aware of oral problems associated with tobacco use. Counselling on smoking cessation and smoking prevention programmes should be an integral component of medical and dental teaching and practice.

Are periodontal diseases risk factors for certain systemic disorders--what matters to medical practitioners?

OBJECTIVE

To review recent data on the nature and pathobiology of periodontal infections and to elaborate how periodontal infections might increase susceptibility to some important systemic diseases and conditions.

DATA SOURCES

Medline literature search and websites of the American Academy of Periodontology and American Medical Association.

STUDY SELECTION

Literature and data on periodontal diseases and their links to systemic diseases.

DATA EXTRACTION

Review of relevant information and data.

DATA SYNTHESIS

Periodontal diseases, including gingivitis and periodontitis, are among the most common infections of humans. They are induced by bacteria and bacterial products of dental plaque and are characterised by inflammatory destruction of tooth-supporting connective tissues and alveolar bone. A growing body of scientific evidence has shown that severe periodontitis may enhance susceptibility to certain important systemic diseases and conditions, for example, cardiovascular disease, diabetes mellitus, adverse pregnancy outcomes, and pulmonary infections. The clinical implications of the emerging specialty of periodontal medicine for dental and medical practitioners are postulated.

CONCLUSIONS

Periodontal diseases may be risk factors for cardiovascular disease, diabetes mellitus, adverse pregnancy outcomes, and pulmonary infections. Dental and medical practitioners should be aware of the clinical implications of these inter-relationships and treat affected patients in collaboration for better oral and general health.

Oral colonisation by aerobic and facultatively anaerobic Gram-negative rods and yeast in Tibetans living in Lhasa

Sample groups of children (n=50) and adults (n=38) were selected from pools of 207 children, (11-13-year olds from two primary schools) and 94 adults (25-44-year olds from four governmental agencies) who were the subjects of an oral health survey among Tibetans living in Lhasa, Tibet Autonomous Region. Mean ages of the study groups of children (38% females) and adults (61% females) were 11.6+/-0.9 and 37.1+/-6.1 years, respectively. All had lived in Tibet since birth. Oral rinse samples were selective cultured to isolate, quantify and speciate aerobic and facultatively anaerobic Gram-negative rods (using the API 20E kit) and yeasts (using API 20C AUX and API ZYM kits). For children, the isolation rates for oral coliform bacteria and yeasts were 84 and 14%, respectively, for adults, the respective rates were 26 and 40%. The corresponding quantities of coliforms/yeasts for children and adults were 0.4+/-1.6 x 10(3)c.f.u./15.8+/-72.3 and 0.2+/-0.6 x 10(3)c.f.u./57.2+/-137.5c.f.u. per millilitre oral rinse, respectively. Aerobic and facultatively anaerobic Gram-negative rods and Stenotrophomonas maltophilia, a free-living saprophytic and ubiquitous bacterial species of wide geographic distribution, were significantly more frequently recovered from the children's oral rinses. The isolation rates of facultatively anaerobic Gram-negative rods in adults and yeasts in both groups were similar to those found in similar cohorts from southern China in earlier studies. Randomly amplified polymeric DNA analysis showed that the S. maltophilia spp. isolated from children were of several different clonal types and were school specific. This study shows that the colonisation rate of facultatively anaerobic Gram-negative rods in adults and yeasts in both groups are similar to those in populations living at lower altitudes, the native young, urban Tibetans appear to exhibit a high oral carriage rate of S. maltophilia spp.

Subgingival microbiota of renal transplant recipients

Renal transplant patients undergoing immunosuppressive therapy may experience periodontal side-effects such as gingival overgrowth. This study evaluated the subgingival microbiota of renal transplant recipients with or without periodontal tissue destruction who may have concurrent gingival enlargement. Subgingival paper point samples taken from the deepest probing sites of 38 subjects (one per patient) were examined using direct microscopy and culture techniques. A complex microflora comprising gram-positive and gram-negative cocci, rods and filaments, fusiforms, curved rods and spirochetes was observed using microscopy. Yeasts were occasionally detected. Significantly higher proportions of gram-positive morphotypes, including gram-positive cocci, were observed in samples from periodontally healthy patients. The predominant cultivable microflora from anaerobic culture comprised several species of facultative and obligate anaerobes. Colonization of the subgingival sites by 'foreign' microbes that are normally dermal, intestinal or vaginal flora was detected in up to 50% of the samples. High mean proportions of lost or unidentified species were also occasionally noted. The results showed that the subgingival biofilm of renal transplant recipients with chronic periodontitis comprised mainly gram-negative rods and spirochetes. Besides the usual predominant cultivable subgingival microbiota associated with periodontitis, the high prevalence of unidentified and 'foreign' microbes indicates the possibility of subgingival microbial alteration in renal transplant patients.

Relationship of changes in interleukin-8 levels and granulocyte elastase activity in gingival crevicular fluid to subgingival periodontopathogens following non-surgical periodontal therapy in subjects with chronic periodontitis

OBJECTIVES

To determine the effect of scaling and root planing (SRP) on the interrelations of subgingival periodontopathogens and both interleukin-8 (IL-8) and granulocyte elastase activity in gingival crevicular fluid (GCF), and to assess their relations to the short-term treatment response in management of chronic periodontitis.

MATERIAL AND METHODS

GCF and subgingival plaque were collected from 16 subjects with untreated chronic periodontitis at baseline and 4 weeks after SRP. IL-8 levels were determined by ELISA. Granulocyte elastase activity was analyzed with a specific substrate, pGluProVal-pNA, and the maximal rate of elastase activity (MR-EA) was calculated. 5 DNA-probes were used to detect the presence of A. actinomycetemcomitans (A. a.), B. forsythus (B.f.), P. gingivalis (P.g.), P. intermedia (P.i.), and T. denticola (T.d.), with a sensitivity = 103 cells/paper point.

RESULTS

IL-8 and MR-EA levels in GCF decreased significantly after SRP (p < 0.001) with a corresponding reduction of total count of the species. Of the sites with probing depth (PD) >/= 5.0 mm and co-infection by B.f., P.g., P.i. & T.d. at baseline, the sites without persistent co-infection of these species after SRP exhibited a significant reduction of IL-8 levels (p < 0.02), MR-EA levels (p < 0.02) and PD (p < 0.01). No such change was found in the sites where such a co-infection persisted. Moreover, reduction of IL-8 levels in those pocket sites was accompanied by a concomitant reduction of MR-EA (p < 0.02) and PD (p < 0.01), while no significant change in MR-EA levels and PD was noted in those pocket sites that exhibited an increase of IL-8 levels after SRP. At baseline, the former group of sites showed significantly higher IL-8 levels than the latter group of sites (p < 0.02).

CONCLUSIONS

IL-8-related granulocyte elastase activity was related to the change in infection patterns of the target periodontopathogens following scaling and root planing. Varying initial IL-8 levels in GCF and a corresponding shifting change of granulocyte elastase activity in GCF may characterize the different short-term treatment responses.

Granulocyte elastase, matrix metalloproteinase-8 and prostaglandin E2 in gingival crevicular fluid in matched clinical sites in smokers and non-smokers with persistent periodontitis

BACKGROUND/AIMS

Smokers with persistent periodontitis may have granulocytes with impaired function. This study aimed to determine the levels of granulocyte elastase, matrix metalloproteinase-8 (MMP-8) and prostaglandin E2 (PGE2) in gingival crevicular fluid (GCF) in smokers and non-smokers with persistent periodontitis.

METHODS

We analyzed GCF from 70 matched sites in 29 periodontitis and 6 gingivitis sites in 34 subjects, 17 smokers, and 17 non-smokers. We also analyzed separately GCF from 28 of these subjects, 14 smokers and 14 non-smokers in 14 matched periodontitis sites. The following measurements were made: elastase complexed to alpha1-antitrypsin (EA-alpha1AT) and MMP-8 with ELISA, functional elastase with a chromogenic substrate, and PGE2 with radioimmunoassay (125I RIA). The significance of the findings was determined with Mann-Whitney test.

RESULTS

In the 29 matched periodontitis sites, smokers had significantly more functional elastase (p<0.005) and more EA-alpha1AT (p<0.05) than non-smokers. In the 14 matched periodontitis sites in 14 smokers and 14 non-smokers, the former had significantly more functional elastase than the latter (p<0.001). A significant correlation was found between EA-alpha1AT and MMP-8 in smokers (p<0.05) and non-smokers (p<0.001) and a positive correlation between levels of functional elastase and MMP-8 in non-smokers (r2=0.98; p<0.001).

CONCLUSIONS

Granulocyte function seems to be impaired in smokers with persistent periodontitis. The cells react to the bacterial challenge by releasing serine proteases, which reflect the degradation of connective tissue. The risk of progression of the disease is therefore higher in smokers with persistent periodontitis than in non-smokers.

Miniaturized electrophoresis: an evolving role in laboratory medicine

The promise of capillary electrophoresis (CE) for supplanting conventional methods in the clinical laboratory led to intense interest in this analytical tool a decade ago. Since then, a number of clinical applications have been defined along with those that have impacted the pharmaceutical, environmental, and forensic arenas. Concurrent with the development of CE applications was the emergence of electrophoresis in the microchip format. The main attraction of this platform, the ability to execute high-resolution separations in a few hundred seconds, was not its only attribute. The capability for parallel processing of separations was complemented by the potentialfor integrating sample preparation into the same device. This Review highlights recent progress towards CE and microchip electrophoresis as clinical diagnostic tools, with literature coverage from 1996 to 2000.

Dynamic labeling during capillary or microchip electrophoresis for laser-induced fluorescence detection of protein-SDS complexes without pre- or postcolumn labeling

The analysis of proteins under denaturing conditions is routinely performed with SDS-polyacrylamide gel electrophoresis. The automated capabilities of CE, use of nongel sieving matrixes, and on-line optical detection by either ultraviolet (UV) absorption or laser-induced fluorescence (LF) promise to revolutionize this method. While direct on-line detection of proteins is possible as a result of their intrinsic ability to absorb light in the UV part of the spectrum (detection sensitivity comparable to Coomassie Blue staining of gels), LIF provides more powerful detection but requires pre- or postcolumn fluorescence labeling of the proteins. The development of a protocol analogous to that used for double-stranded DNA analysis, where fluorescent intercalating dyes are simply included in the separation medium, would simplify size-based protein analysis immensely. This would avoid the complications associated with covalent modification of the proteins but still exploit the sensitivity of LIF detection. We demonstrate that this is possible with CE and microchip detection by incorporating, into the run buffer, a fluorescent dye that interacts hydrophobically with protein-SDS complexes. Key to this is a dye that fluoresces significantly when bound to protein-SDS complexes but not when bound to SDS micelles. Comparison of electropherograms from CE-based denaturing protein analysis with UV and LIF detection indicates that the presence of the fluor does not alter separation of the proteins. Moreover, comparison with electropherograms generated from microchip electrophoresis with LIF detection shows that equivalent patterns can be obtained. Despite the unoptimized nature of this separation system, a dynamic labeling protocol that allows for LIF detection for proteins is attractive and has the potential to circumvent the tedious labeling steps typically required.

Oral colonization of aerobic and facultatively anaerobic gram-negative rods and cocci in irradiated, dentate, xerostomic individuals

This study aimed at investigating the oral colonization of aerobic and facultatively anaerobic gram-negative rods and cocci in head- and neck-irradiated, dentate, xerostomic individuals. Subjects were recruited from a nasopharyngeal carcinoma clinic and were segregated into group A: <60 years (n=25, 48+/-6 years, 5+/-5 years post-irradiation) and group B: >or=60 years (n=8, 67+/-4 years, 2+/-2 years post-irradiation) and were compared with age- and sex-matched normal individuals, group C: <60 years (n=20, 44+/-12 years) and group D: >or=60 years (n=10, 70+/-3 years). Selective culture of the oral rinse samples was carried out to isolate, quantify and speciate (using API 20E kit) aerobic and facultatively anaerobic gram-negative rods and cocci recovery. All test subjects were put under comprehensive oral and preventive care for 3 months, and 12 group A and 5 group B subjects were recalled for reassessment of aerobic and facultatively anaerobic gram-negative rods and cocci colonization. All identical isolates, pre- and post-hygienic care, were phenotypically (Vitek, Hazelwood, MA and antibiogram profile) and genotypically (pulsed-field gel electrophoresis) evaluated. The aerobic and facultatively anaerobic gram-negative rods and cocci isolated from the first round oral rinse samples included: Acinetobacter, Neisseria, Chryseomonas, Flavimonas, Pseudomonas, Citrobacter, Enterobacter, Escherichia, Klebsiella, Flavobacterium and Weeksella species. The aerobic and facultatively anaerobic gram-negative rods and cocci isolation rate was high for irradiated individuals, and they were 64/25% and 100/80% for groups A/C and B/D, respectively. Recovery of aerobic and facultatively anaerobic gram-negative rods and cocci and Klebsiella pneumoniae subsp. pneumoniae in oral rinse samples were found to be significantly more prevalent in the irradiated subjects (groups A and B). Enterobacteriaceae were more frequently isolated from oral rinse samples of aged irradiated subjects (group B vs D, P<0.05), where the quantity of Citrobacter freundii (colony-forming units/ml oral rinse) was also significantly elevated. The isolation rate of aerobic and facultatively anaerobic gram-negative rods and cocci after hygienic care remained unchanged; 3 of 12 and 3 of 5 of the recalled subjects from groups A and B, respectively, harbored same aerobic and facultatively anaerobic gram-negative rods and cocci species. However, only two pairs of K. pneumoniae subsp. pneumoniae, sequentially isolated from same patients in group B, were found to be identical by pulsed-field gel electrophoresis. This may be due to reinfection of the microbes from the same source or permanent colonization. In conclusion, irradiation-induced xerostomia seems to favor frequent, repeated, transient intraoral colonization of aerobic and facultatively anaerobic gram-negative rods and cocci.

Oral health status and treatment need of 11-13-year-old urban children in Tibet, China

OBJECTIVE

To describe the oral health status and treatment need of 11-13-year-old children in urban Tibet and to determine if there was a difference in oral health status between the Tibetan and Han children. SURVEY DESIGN AND SUBJECTS: The two largest primary schools in Lhasa, Tibet, were selected and all children aged between 11 and 13 years were surveyed. Each child was interviewed and clinically examined in the schools, using portable equipment, by one of four calibrated examiners. The examination procedures and diagnostic criteria used followed those recommended by the World Health Organization.

RESULTS

347 children (207 Tibetans and 140 Han) were surveyed. Over 90% of the children claimed to brush their teeth at least once a day. Three-quarters had never visited a dentist. Caries prevalence was 44% in the Tibetans and 24% in the Han (P<0.001). The mean DMFT scores of the Tibetans and Han were 0.8 and 0.4 respectively (P<0.001). Only 1% of the children in both ethnic groups had healthy gums (highest CPI score = 0) and about two-thirds of them had calculus. One-third of the children were in need of treatment for dental caries and most of the required treatment items were one-surface fillings but 10% of the children needed extraction.

CONCLUSION

Dental caries and treatment need level of both Tibetan and Han children in Tibet was low but their periodontal health status was unsatisfactory.

[Cloning and sequencing of the maize ribosome-inactivating protein gene]

A gene encoding maize Ribosome-inactivating protein was amplified by means of PCR using mRNA of maize leaves as a template, and cloned into pUC19 vector. The amplified DNA sequence has been determined, which consists of 828 bp and encodes 275 amino acid residues. Comparison with previously reported sequence shows 98.4% homologies in nucleotide sequence and 97.4% in amino acid sequence, respectively.

Oral colonization, phenotypic, and genotypic profiles of Candida species in irradiated, dentate, xerostomic nasopharyngeal carcinoma survivors

The aim of this study was to investigate oral yeast colonization and oral yeast strain diversity in irradiated (head and neck), dentate, xerostomic individuals. Subjects were recruited from a nasopharyngeal carcinoma clinic and were segregated into group A (age, <60 years [n = 25; average age +/- standard deviation (SD), 48 +/- 6 years; average postirradiation time +/- SD, 5 +/- 5 years]) and group B (age, >/=60 years [n = 8; average age +/- SD, 67 +/- 4 years; average postirradiation time +/- SD, 2 +/- 2 years]) and were compared with age- and sex-matched healthy individuals in group C (age, <60 years [n = 20; average age +/- SD, 44 +/- 12 years] and group D (age, >/=60 years [n = 10; average age, 70 +/- 3 years]). Selective culture of oral rinse samples was carried out to isolate, quantify, and speciate yeast recovery. All test subjects underwent a 3-month comprehensive oral and preventive care regimen plus topical antifungal therapy, if indicated. A total of 12 subjects from group A and 5 subjects from group B were recalled for reassessment of yeast colonization. Sequential (pre- and posttherapy) Candida isolate pairs from patients were phenotypically (all isolate pairs; biotyping and resistotyping profiles) and genotypically (Candida albicans isolate pairs only; electrophoretic karyotyping by pulsed-field gel electrophoresis, restriction fragment length polymorphism [RFLP], and randomly amplified polymorphic DNA [RAPD] assays) evaluated. All isolates were Candida species. Irradiated individuals were found to have a significantly increased yeast carriage compared with the controls. The isolation rate of Candida posttherapy remained unchanged. A total of 9 of the 12 subjects in group A and 3 of the 5 subjects in group B harbored the same C. albicans or Candida tropicalis phenotype at recall. Varying degrees of congruence in the molecular profiles were observed when these sequential isolate pairs of C. albicans were analyzed by RFLP and RAPD assays. Variations in the genotype were complementary to those in the phenotypic characteristics for some isolates. In conclusion, irradiation-induced xerostomia seems to favor intraoral colonization of Candida species, particularly C. albicans, which appeared to undergo temporal modifications in clonal profiles both phenotypically and genotypically following hygienic and preventive oral care which included topical antifungal therapy, if indicated. We postulate that the observed ability of Candida species to undergo genetic and phenotypic adaptation could strategically enhance its survival in the human oral cavity, particularly when salivary defenses are impaired.

High-speed chiral separations on microchip electrophoresis devices

High-speed electrophoretic chiral separations have been successfully performed in a microfabricated device by employing cyclodextrin-modified micellar electrokinetic chromatography (CD-MEKC). Utilizing short separation channels and relatively high field strengths in combination with small volume-defined injection plugs, and operating in counter-electroosmotic flow conditions, fast and efficient separations of fluorescein insothiocyanate (FITC)-labeled amino acid enantiomers were obtained. Analysis time ranged from 75 s for the most basic amino acids to 160 s for the most acidic ones with associated efficiencies from 7000 up to 28 000 effective plates (100 000 to 395 000 plates/m). Buffer parameters were varied in order to study the effect on chiral resolution. A buffer system consisting of 100 mM borate (pH 9.4), 30 mM of SDS, and 10 mM gamma-CD as chiral selector provided adequate resolution of the majority of FITC-amino acid enantiomers tested.

Screening of carbohydrates in urine by capillary electrophoresis

Carbohydrate analysis of urine is clinically important in assisting diagnosis of disorders of carbohydrate metabolism and understanding its pathologic significance. Paper chromatography and thin-layer chromatography are the techniques that are often employed for the determination of urinary carbohydrates. An aim of our experiments was to investigate the utility of capillary electrophoresis to develop a fast screening procedure of urinary carbohydrates. Simultaneous resolution of eight carbohydrates involving maltose, lactose, D-mannose, D-glucose, D-ribose, D-xylose, L-arabinose and D-galactose as markers was obtained with 130 mM borate (pH 10.2). Ethanol/water (80/20 v/v) and acetonitrile proved to be efficient reagents for urine sample clean-up which produced symmetrical peaks. The urine sample from a normal subject was determined to contain lactose, glucose, xylose and arabinose that fall within normal ranges of these carbohydrates in urine. The investigations made in this study may be potentially useful in carbohydrate screening, especially in neonatal urine screening.

Granulocyte elastase activity and PGE2 levels in gingival crevicular fluid in relation to the presence of subgingival periodontopathogens in subjects with untreated adult periodontitis

This study aimed to determine the association between the levels of granulocyte elastase and prostaglandin E2 (PGE2) in GCE and the concomitant presence of periodontopathogens in untreated adult periodontitis (AP). GCF and subgingival plaque were sampled by paper strips and paper points respectively, from various periodontal sites in 16 AP subjects. Granulocyte elastase activity in GCF was analyzed with a low molecular weight substrate specific for granulocyte elastase, pGluProVal-pNA, and the maximal rate of elastase activity (MR-EA, mAbs/min/site) was calculated. PGE2 levels in GCF were determined by radioimmunoassay. 5 species-specific DNA probes were used to detect the presence of A. actinomyceterncomitans (A.a., ATCC 43718), B. forsythus (B.f, ATCC 43037), P. gingivalis (P.g., ATCC 33277), P. intermedia (P.i., ATCC 33563), and T. denticola (T.d., ATCC 35405), with a sensitivity of 10(3) cells/paper point. No A.a. was detectable from all sites sampled. The predominant combination of species detected was B.f., P.g., P.i. & T.d. and it was significantly higher at periodontitis sites (68%) than at healthy (7%) or gingivitis sites (29%) (p<0.05). Overall, MR-EA values were strongly correlated with PGE2 levels (r=0.655, p<0.001), especially at these periodontitis sites co-infected by B.f., P.g., P.i. & T.d. (r=0.722, p<0.001). The periodontitis sites co-infected by the 4 species were observable from 15 subjects. These sites were sub-grouped into 8 subjects with a high MR-EA and 7 subjects with a low MR-EA. The PGE2 levels in the high MR-EA group were significantly higher than in the low MR-EA group (p<0.05). No significant differences in clinical or bacterial data were found between the two groups. While within the high MR-EA group, similar results were found between the paired periodontitis sites in each subject with highest and lowest MR-EA values. This study shows that the local host response to bacterial challenge in untreated periodontal pockets is diverse in terms of the intensity of inflammatory response measured by granulocyte elastase and PGE2 levels in GCE A more thorough evaluation of the risk for active periodontal disease may involve the combined approaches to the test of the dynamic bacteria-host relations.

Indirect laser-induced fluorescence detection of valproic acid in human serum by capillary electrophoresis

A capillary electrophoresis (CE) method with indirect laser-induced fluorescence detection for the analysis of valproic acid in human serum has been explored. The buffer system was optimized with 2.5 mM borate-phosphate at pH 8.4; fluorescein sodium was used to generate background signal at a concentration of 6 microM. Hexanoic acid was selected as internal standard. Serum sample was deproteinized by acetonitrile. Analysis was performed by direct injection of the supernatant. CE separation was carried out at 30 kV and the total analysis time was less than 15 min, including sample treatment and electrophoresis time. No interference from other common anticonvulsant drugs occurred under the experimental conditions used. The interference of human serum matrix was reduced by using a high ratio of acetonitrile to serum (minimum 5:1) for deproteinization. Interference of ionic components in serum could occur, depending on the sample source. The linear range of concentrations for standard drug was between 4.5-144.0 microg/mL (r = 0.9947). The limit of detection was 0.9 microg/mL at S/N > or = 3; the limit of quantitation at S/N > or = 20 was 3 microg/mL. The recoveries of valproic acid spiked into serum were 69.2% and 60.2% for concentration levels of 90 and 54 microg/mL, respectively. This CE method was shown to be successful in the analysis of valproic acid in standard solutions. However, interference from the matrix was observed in the analysis of this compound in serum samples. Additional work should be done to develop a highly selective sample preparation technique.