Autogenous bone graft and ePTFE membrane in the treatment of peri-implantitis. I. Clinical and radiographic observations in cynomolgus monkeys

The purpose of the study was to examine the effect of autogenous bone graft particles and expanded polytetrafluoroethylene (ePTFE) membrane in the treatment of peri-implantitis. The treatment outcome was evaluated by clinical and radiographic methods including quantitative digital subtraction radiography. A total of 64 implants with a titanium plasma-sprayed (TPS) surface was inserted in eight cynomolgus monkeys (Macaca fascicularis). After a 3-month healing period with plaque control, experimental peri-implantitis characterized by a bone loss of 4-6 mm was established during 14-22 months. Plaque control was then re-implemented and surgical treatment involving autogenous bone+membrane (B+M), autogenous bone (B), membrane (M), or a conventional flap procedure alone (control) (C) was performed. The animals were killed 6 months after treatment. Healthy peri-implant tissue was established irrespective of the applied surgical procedure. A mean bone gain of 4.7 mm was identified around implants treated with B+M, while, respectively, 4.0, 3.0, and 1.9 mm were recorded within the B, M, and C groups. Quantitative digital subtraction radiography confirmed considerable bone gain within defects treated with autogenous bone with or without membrane coverage. The bone gain, especially for defects treated with B+M, seemed to be almost to the level before development of peri-implantitis. By contrast, 38 and 25% of the defect was on average characterized by bone gain when, respectively, M or C was used alone. The present study of implants with a TPS surface in cynomolgus monkeys thus demonstrates considerable bone regeneration after treatment of experimental peri-implantitis with autogenous bone graft particles with or without ePTFE membrane coverage. Further stereologic and histologic evaluation of the treatment outcome is necessary before final conclusions about the effect of autogenous bone graft and ePTFE membrane can be made.     

Implant surface preparation in the surgical treatment of experimental peri-implantitis with autogenous bone graft and ePTFE membrane in cynomolgus monkeys

The aim of the present investigation was to assess the effect of four implant surface preparation methods used in the surgical treatment of experimental peri-implantitis with autogenous bone graft and expanded polytetrafluoroethylene (ePTFE) membrane. The methods were air-powder abrasive unit+citric acid, air-powder abrasive unit, gauze soaked in saline+citric acid, and gauze soaked alternately in chlorhexidine and saline. A total of 64 implants with a titanium plasma-sprayed (TPS) surface was placed in eight cynomolgus monkeys (Macaca fascicularis). After a 3-month period with plaque control, experimental peri-implantitis was induced. A bone loss of 4-6 mm was established after 9-17 months and plaque control was re-implemented. The peri-implantitis defects were surgically exposed, granulation tissue was removed, and each implant surface was prepared by one of the above-mentioned procedures. The defects were then filled with autogenous bone graft particles and covered by an ePTFE membrane. The animals were sacrificed after 6 months. Evaluation by clinical parameters, radiography including quantitative digital subtraction radiography, histology, and stereology did not reveal significant differences between the methods. Almost total bone regeneration and considerable re-osseointegration were obtained irrespective of the method applied. A mean bone-to-implant contact of 39-46% was observed within the defects. Therefore, the present study of implants with a TPS surface in cynomolgus monkeys indicates that the simplest method involving gauze soaked alternately in chlorhexidine and saline should be the preferred implant surface preparation method in the surgical treatment of peri-implantitis involving autogenous bone graft and ePTFE membrane.     

The second activating glucokinase mutation (A456V): implications for glucose homeostasis and diabetes therapy

In this study, a second case of hyperinsulinemic hypoglycemia due to activation of glucokinase is reported. The 14-year-old proband had a history of neonatal hypoglycemia, treated with diazoxide. He was admitted with coma and convulsions due to nonketotic hypoglycemia. His BMI was 34 kg/m(2), and his fasting blood glucose ranged from 2.1 to 2.7 mmol/l, associated with inappropriately high serum levels of insulin, C-peptide, and proinsulin. An oral glucose tolerance test (OGTT) showed exaggerated responses of these peptides followed by profound hypoglycemia. Treatment with diazoxide and chlorothiazide was effective. His mother never had clinical hypoglycemic symptoms, even though her fasting blood glucose ranged from 2.9 to 3.5 mmol/l. Increases in serum insulin, C-peptide, and proinsulin in response to an OGTT suggested a lower threshold for glucose-stimulated insulin release (GSIR). Screening for mutations in candidate genes revealed a heterozygous glucokinase mutation in exon 10, substituting valine for alanine at codon 456 (A456V) in the proband and his mother. The purified recombinant glutathionyl S-transferase fusion protein of the A456V glucokinase revealed a decreased glucose S(0.5) (the concentration of glucose needed to achieve the half-maximal rate of phosphorylation) from 8.04 (wild-type) to 2.53 mmol/l. The mutant's Hill coefficient was decreased, and its maximal specific activity k(cat) was increased. Mathematical modeling predicted a markedly lowered GSIR threshold of 1.5 mmol/l. The theoretical and practical implications are manifold and significant.     

Relations between various measures of iodine intake and thyroid volume,thyroid nodularity,and serum thyroglobulin

BACKGROUND: Iodine intake can be measured in various ways, and each method may have advantages and disadvantages. OBJECTIVE: We sought to investigate the potential associations of various measures of iodine intake with thyroid volume, prevalence of thyroid nodules, and serum thyroglobulin. We also sought to identify, if possible, groups at risk of thyroid disease because of their food choices. DESIGN: This cohort study included 4649 randomly selected subjects with mild-to-moderate iodine deficiency; the subjects lived in 2 cities in Denmark. Iodine intake was estimated by using a food-frequency questionnaire and by measuring iodine excretion in spot urine samples. Thyroid volume and nodularity were measured with ultrasonography. RESULTS: In multiple linear regression models, significant inverse relations were found between thyroid volume and estimated 24-h iodine excretion, iodine intake from diet plus supplements, iodine intake from diet/kg body wt, and milk intake (P = 0.001 for all), but not urinary iodine excretion measured as a concentration (P = 0.40). All measures of iodine intake were significantly related to serum thyroglobulin concentration (P 相似文献   

Chronic pain in land mine accident survivors in Cambodia and Kurdistan

The aims of the study were to study chronic pain in land mine accident survivors, and to study the impact of trauma and trauma care parameters on chronic pain. The level of chronic pain was registered (patient-rated and by clinical examination) in 57 severely injured adult land mine accident survivors in Cambodia and Northern Iraq more than one year after the accident. As all study patients had been managed by a standardized trauma system, we could assess the impact of injury severity and primary trauma care on chronic pain. 64% of the study patients (n=36) had chronic pain syndromes (non-significant difference between the two countries). 68% of the amputees (19 out of 28) had phantom limb pain. Pre-injury trauma exposure, the severity of the actual trauma, and the quality of trauma care had no impact on end point chronic pain. In 85% of cases (n=48), the economic standing of the patients' family had deteriorated after the accident. Patient-rated loss of income correlated with the rate of chronic pain syndromes.     

Soil microbial toxicity of eight polycyclic aromatic compounds: effects on nitrification,the genetic diversity of bacteria,and the total number of protozoans

Eight polycyclic aromatic compounds (PACs) were tested for their toxic effect on the soil nitrification process, bacterial genetic diversity, and the total number of protozoans (naked amoebae and heterotrophic flagellates). After four weeks of exposure in a well-characterized agricultural soil, toxic effects were evaluated by comparison to uncontaminated control soils. All PACs affected the nitrification process, and the calculated no-observed-effect concentrations (NOECs) for nitrification were 79 mg/kg for pyrene, 24 mg/kg for fluoranthene, 26 mg/kg for phenanthrene, 72 mg/kg for fluorene, 23 mg/kg for carbazole, 22 mg/kg for dibenzothiophene, 75 mg/kg for dibenzofuran, and 1,100 mg/kg for acridine. For all substances but acridine, nitrification was the most sensitive of the three toxicity indicators evaluated. No effect of the tested substances on bacterial diversity was found, as measured by denaturant gradient gel electrophoresis. In general, only weak effects at very high concentrations were found for the protozoans. However, for acridine, protozoan numbers were reduced at lower concentrations than those that affected the nitrification process, that is, with a 5% reduction at 380 mg/kg. For effects on nitrification, toxicity (NOEC values) expressed as soil pore-water concentrations (log10(micromol/L)) showed a significant inverse relationship with lipophilicity (log octanol-water partition coefficient) of the substances (r2 = 0.69, p = 0.011, n = 8). This finding could indicate that the toxicity of substances similar to those tested might be predicted by a quantitative structure-activity relationship with lipophilicity as the predictor variable.     

Allelic deletions of Rb and L-myc in urine sediments from patients with bladder tumors or carcinoma in situ

In a previous study we found allelic imbalances of Rb and L-myc associated with disease stage and disease course in bladder cancer. The primary aim of the present study was to determine whether the changes found in tumors were reflected in urine sediments. Secondly we wanted to test if Rb and L-myc were frequently lost in urine sediments from patients with carcinoma in situ and no bladder tumor at present. Based on this we examined allelic deletions of the Rb and L-myc genes in tumor and urine from 55 patients with bladder tumors or carcinoma in situ. Deletions were examined on extracted DNA from tumors and urine sediments by the use of microsatellite markers located as close to the genes as possible. Fifty-five patients and 10 controls were included. We found no strict correlation between allelic deletions in bladder tumors and urine sediments from the same patient. Allelic deletions in urine sediments were at least as common in patients with carcinoma in situ and no bladder tumor (32%) as in patients with bladder tumors (20%). It was possible to identify allelic deletions in urine sediment from 1 patient with cystitis and no history of malignant bladder disease (6%). In conclusion we found no strict correlation between allelic deletions in bladder tumors and urine sediments. Allelic deletions in urine sediments seem to be at least as common in patients with carcinoma in situ as in patients with bladder tumors.     

Analysis of gene induction in human fibroblasts and bladder cancer cells exposed to the methylation inhibitor 5-aza-2'-deoxycytidine

Hypermethylation of the promoters of cancer-related genes is often associated with their inactivation during tumorigenesis. Several preclinical and clinical trials have been developed to use DNA methylation inhibitors, such as 5-aza-2'-deoxycytidine (5-Aza-CdR) in attempts to reactivate silenced genes in human cancers. We used high-density oligonucleotide gene expression microarrays to examine the effects of 5-Aza-CdR treatment on human fibroblast cells (LD419) and a human bladder tumor cell line (T24). Data obtained 8 days after recovery from 5-Aza-CdR treatment showed that more genes were induced in tumorigenic cells (61 genes induced; >or=4-fold) than nontumorigenic cells (34 genes induced; >or= 4-fold). Approximately 60% of induced genes did not have CpG islands within their 5' regions, suggesting that some genes activated by 5-Aza-CdR may not result from the direct inhibition of promoter methylation. Interestingly, a high percentage of genes activated in both cell types belonged to the IFN signaling pathway, confirming data from other tumor cell types.