Effects of autoclave sterilization on properties of dental rubber dam as related to its use as barrier membrane in guided tissue regeneration

BACKGROUND AND OBJECTIVE: Dental rubber dams (RDs) were used as barrier membranes in guided tissue regeneration for the treatment of periodontal intraosseous defects with acceptable clinical results. The aim of the present study was to investigate the effects of autoclave sterilization on properties of RD as related to its use as a barrier membrane in guided tissue regeneration. METHODS: RDs were sterilized by either an autoclave, gamma irradiation, or chemical agents and then co-cultured with human gingival fibroblasts. The cell responses to sterilized RDs were investigated by inverted phase contrast microscopy, scanning electron microscopy (SEM) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) technique. The surface alterations of the autoclaved RDs were observed under SEM. The tensile strength, tear strength and elongation at break of the autoclaved RDs were tested by a universal testing machine. RESULTS: The results from cell culture, microscopic and MTT studies showed that RDs sterilized by autoclave and gamma irradiation did not deteriorate gingival fibroblasts and provided surfaces suitable for cell attachment, whereas chemical-sterilized RDs were toxic to these cells. Ultrastructurally, surface changes from the non-autoclaved RDs, including some melted areas, small pores and folds were observed on the autoclaved RD surface. The tensile strength and tear strength of the autoclaved RDs were significantly lower than those of the non-autoclaved RDs (p = 0.042, p < 0.001, respectively). In contrast, the elongation at break of the autoclaved RDs was higher than that of the non-autoclaved RDs (p < 0.001). CONCLUSION: These results suggest that the autoclave sterilization deteriorated the physical properties of RDs even though they seemed to be compatible to the cultured human cells. Therefore, the sterilization method should be taken into consideration when RDs are utilized as barrier membranes.     

Highest accuracy of combined consensus clinical criteria and SNRPN gene molecular markers in diagnosis of Prader-Willi syndrome in Thai patients.

BACKGROUND: Prader-Willi Syndrome (PWS) is a complex human genetic disease arising from a loss of paternal allele expression of imprinting genes on chromosome 15q11-q13. Normally the CpG islands at this site are heavily methylated in the maternal allele, but unmethylated in the paternal allele and therefore activated in gene expression. only the methylated allele should present in pws patients when methylation-specific pcr (msp) is analyzed. METHODS: This paper reports an analysis of PWS in Thai patients using consensus diagnostic criteria based on a combination of clinical data, basic G-banding and fluorescence in situ hybridization (FISH) cytogenetics, PCR-based methylation assay, and bisulfite sequencing of the CpG islands of SNRPN to confirm 15q deletion or the methylation pattern of the SNRPN promoter and exon 1. Lack of complete clinical reports or inadequacy of the minimum laboratory support required had made it difficult to diagnose PWS, Angelman syndrome and other microdeletion disorders. RESULTS: Accuracy of 100% was obtained for diagnosis of the PWS study patients using the minimum requirements necessary. A total of 20 patients were diagnosed as PWS based on clinical criteria and the scoring tool for PWS, and the same approach was applied to four separate patients with some unmatched criteria but phenotypic similarity to PWS. Findings showed that 70% of those clinically diagnosed as PWS patients (14/20) had a deletion at 15q11-q13 according to FISH, while all 20 patients showed MSP positive of SNRPN gene. Six cases (30%) without a paternal deletion were confirmed to have maternal uniparental disomy (mUPD) of PWS by MSP and methylation sequencing approaches. Noteworthy, two of the six cases with mUPD were 3.5 year-old twins. None of the five cases with scores lower than the reported consensus criteria showed positive G-band, FISH or MSP results. CONCLUSIONS: We demonstrate here the high power of combining clinical findings, FISH and MSP in definitive diagnosis of PWS and in distinguishing between the two major different types of molecular mechanisms. No false positives or false negatives were observed in our analysis.     

Urinary pesticide metabolites in school students from northern Thailand

We evaluated exposure to pesticides among secondary school students aged 12-13 years old in Chiang Mai Province, Thailand. Pesticide-specific urinary metabolites were used as biomarkers of exposure for a variety of pesticides, including organophosphorus insecticides, synthetic pyrethroid insecticides and selected herbicides. We employed a simple solid-phase extraction with analysis using isotope dilution high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). A total of 207 urine samples from Thai students were analyzed for 18 specific pesticide metabolites. We found 14 metabolites in the urine samples tested; seven of them were detected with a frequency > or=17%. The most frequently detected metabolites were 2-[(dimethoxyphosphorothioyl) sulfanyl] succinic acid (malathion dicarboxylic acid), para-nitrophenol (PNP), 3,5,6-trichloro-2-pyridinol (TPCY; metabolite of chlorpyrifos), 2,4-dichlorophenoxyacetic acid (2,4-D), cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acids (c-DCCA and t-DCCA; metabolite of permethrin) and 3-phenoxybenzoic acid (3-PBA; metabolite of pyrethroids). The students were classified into 4 groups according to their parental occupations: farmers (N=60), merchants and traders (N=39), government and company employees (N=52), and laborers (N=56). Children of farmers had significantly higher urinary concentrations of pyrethroid insecticide metabolites than did other children (p<0.05). Similarly, children of agricultural families had significantly higher pyrethroid metabolite concentrations. Males had significantly higher values of PNP (Mann-Whitney test, p=0.009); however, no other sex-related differences were observed. Because parental occupation and agricultural activities seemed to have little influence on pesticide levels, dietary sources were the likely contributors to the metabolite levels observed.     

Five-year study of antimicrobial susceptibility and beta-lactamase production in Haemophilus influenzae

We evaluated 582 Haemophilus influenzae isolates from patients between January 2000 and December 2004. Overall, 433 isolates were obtained from sputum and bronchial washings, 124 isolates were from pus, 19 isolates were from blood and 6 isolates form cerebrospinal fluid. H. influenzae was sensitive to amoxicillin/clavulanate, ampicillin/sulbactam, gentamicin, cefuroxime, ceftriaxone, cefotaxime, ciprofloxacin, ofloxacin, imipenem, meropenem (range 97-100%), chloramphenicol (75%), ampicillin/amoxicillin (52%), but resistant to trimethoprim-sulphamethoxazole. As for beta-lactamase production, 48.4% of the isolates tested were positive.     

Serotypes and antimicrobial susceptibilities of Streptococcus pneumoniae isolated from hospitalized patients in Thailand

Two hundred seven Streptococcus pneumoniae isolates were obtained from patients admitted to Siriraj Hospital. One hundred two, and 105 isolates were from sterile sites and non-sterile sites, respectively. They were serotyped by Quellung reaction with specific antisera from Statens Serum Institut; 81.6% of these pneumococci were typeable. These serotypes were included in the 23-valent pneumococcal polysaccharide vaccine. The five most common serotypes were serotype 6 (22.5%), followed by serotype 23 (18.9%), serotype 19 (16.6%), serotype 3 (7.7%) and serotype 11 (5.3%). Among typeable pneumococci (169 isolates), 52.7% were from sterile sites and 47.3% were from non-sterile sites. Serotypes 6, 23 and 19 were the predominant serotypes isolated from sterile sites. Of the 9 drugs tested, pneumococcal isolates were sensitive to ofloxacin (99%), ciprofloxacin (81.5%), meropenem (80%), imipenem (66.5%), ceftriaxone (65%), cefotaxime (63%), erythromycin (58%), penicillin (48%), and trimethoprim-sulfamethoxazole (34.5%).     

Comparison of the bioactive secondary metabolites from the scale insect pathogens, Anamorph Paecilomyces cinnamomeus, and Teleomorph Torrubiella luteorostrata

A scale insect pathogen Paecilomyces cinnamomeus BCC 9616 and its teleomorph Torrubiella luteorostrata BCC 9617, collected on the same host specimen, were fermented and chemically explored. Both fungi produced paecilodepsipeptide A (1) and zeorin (4) as major constituents of mycelia extracts. The culture broth extract of BCC 9616 provided a known diketopiperazine, terezine D (5), and a new xanthone glycoside, norlichexanthone-6-O-beta-(4-O-methylglucopyranoside) (6). On the other hand, the broth extract of BCC 9617 contained small amounts of a new naphthopyrone glycoside, rubrofusarin-6-O-beta-(4-O-methylglucopyranoside) (7) along with 5. Structures of the new compounds, 6 and 7, were elucidated by interpretation of NMR and mass spectroscopic data. The overall results demonstrated that the metabolite profiles of the cultured anamorph (BCC 9616) and teleomorph (BCC 9617) originating from the same host specimen resemble each other closely. The (1)H-NMR spectroscopic analysis of the culture extracts from other strains of P. cinnamomeus and T. luteorostrata revealed that zeorin is the most commonly occurring fermentation product of these fungi, whereas paecilodepsipeptide A was the metabolite specific to the particular isolate BCC 9616/BCC 9617.     

The influence of neck pain on sensorimotor function in the elderly

Greater disturbances in sensorimotor control have been demonstrated in younger to middle aged groups. However, it is unknown whether or not the impairments documented in these populations can be extrapolated to elders with neck pain. The aim of this study was to investigate the influence of neck pain on sensorimotor function in elders. Twenty elders with neck pain (12 women and 8 men) and 20 healthy elder controls (14 women and 6 men) aged 65 years and over were recruited from the general community. Tests for sensorimotor function included; cervical joint position sense (JPS); computerised rod-and-frame test (RFT); smooth pursuit neck torsion test (SPNT); standing balance (under conditions of eyes open, eyes closed on firm and soft surfaces in comfortable stance); step test and ten-meter walk test with and without head movement. Elders with neck pain had greater deficits in the majority of sensorimotor function tests after controlling for effects of age and comorbidities. Significant differences were found in the SPNT (p<0.01), error in the RFT (frame angled at 10° and 15° anticlockwise) (p<0.05), standing balance (amplitude of sway) - eyes open on a firm surface in the medio-lateral (ML) direction (p=0.03), and total number of steps on the step test, both left and right sides (p<0.01). Elders with neck pain have greater sensorimotor disturbances than elders without neck pain, supporting a contribution of altered afferent information originating from the cervical spine to such disturbances. The findings may inform falls prevention and management programs.     

Control of bleeding in children with Dengue hemorrhagic fever using recombinant activated factor VII: a randomized, double-blind, placebo-controlled study.

OBJECTIVES: We evaluated the efficacy and safety of recombinant activated factor VII (rFVIIa) in children aged < 18 years old with grade II or grade III Dengue hemorrhagic fever (DHF) who required blood component therapy for controlling bleeding episodes. STUDY DESIGN: Patients were randomized to the rFVIIa group or placebo group in a ratio of 2:1. rFVIIa or placebo (100 microg/kg body weight) was given by intravenous bolus injection. When bleeding was not effectively controlled, a second dose of rFVIIa or placebo (100 microg/kg) was given 30 min after the first dose. RESULTS: Nine and 16 patients received placebo and rFVIIa, respectively. The demographics, bleeding manifestations and grade of DHF were similar for the rFVIIa and placebo groups. Apart from petechiae and ecchymosis, one to four additional bleeding sites were found in each patient, including hematemesis (n = 15), epistaxis (n = 14), gum bleeding (n = 12), melena (n = 7), hypermenorrhea (n = 4), hematochezia (n = 2) and hematuria (n = 2). The mean total dose of rFVIIa (138.4 +/- 50.9 microg/kg) and placebo (145.4 +/- 53.7 microg/kg) were comparable. The efficacy of bleeding control at 2 h after the first dose was completely ceased (rFVIIa 75.0% versus placebo 44.4%), decreased (rFVIIa 18.7% versus placebo 11.2%), and unchanged or worsened (rFVIIa 6.3% versus placebo 44.4%). Some patients with active bleeding received platelet concentrates 3-12 h after the first dose of rFVIIa or placebo. The subsequent efficacy of bleeding control at 6, 12 and 24 h was comparable between the two groups. The cumulative use of red blood cells (rFVIIa 31.3% versus placebo 33.3%) and plasma (rFVIIa 25% versus placebo 22%) during the 24-h period was not significantly different between the two groups. In contrast, platelet concentrate requirement in the rFVIIa group (6.3%) was lower than the placebo (33.3%). No clinical evidence of thromboembolic complications or mortality as a result of bleeding was observed. CONCLUSION: rFVIIa appears to be a useful adjunctive treatment to blood component transfusion for controlling active bleeding in children with DHF especially when platelet concentrate is not readily available.     

Clinical characteristics and mutation analysis of propionic acidemia in Thailand

Background

Propionic acidemia (PA) is caused by a deficiency of propionyl CoA carboxylase. A characteristic urine organic acid profile includes 3-hydroxypropionate, methylcitrate, tiglylglycine, and propionylglycine. The diagnosis of PA is confirmed by detection of mutations in the PCCA or PCCB genes. We herein report the clinical and molecular findings of four Thai patients with PA.

Methods

Clinical findings of four Thai patients with PA were retrospectively reviewed. Urine organic acids were analyzed by gas chromatography-mass spectrometry. PCR-sequencing analyses of encoding exons and intron/exon boundaries of the PCCA and PCCB genes were performed.

Results

All patients had neonatal onset of PA. One patient died of cardiomyopathy, and another one of pneumonia and metabolic decompensation. The remainder experienced significant neurocognitive impairment. Mutation analysis of the PCCA gene identified homozygous c.1284+1G>A in patient 1, c.230G>A (p.R77Q) and c.1855C>T (p.R619X) in patient 2, homozygous c.2125T>C (p.S709P) in patient 3, and only one mutant allele, c.231+1G>T in patient 4. No PCCB mutation was identified. Four mutations including c.230G>A, c.231+1G>T, c.1855C>T, and c.2125T>C have not been reported previously.

Conclusions

The clinical and molecular study of these Thai patients provided additional knowledge of the genotype and phenotype characteristics of PA. The results of the study suggested that PCCA mutations in Asian populations were distinct from those of other populations.