The effect of different surface treatments of demineralised enamel on microleakage under metal orthodontic brackets

Background

The aim of this investigation was to assess the effects of different treatments of demineralised enamel on microleakage under orthodontic brackets.

Methods

Seventy-five intact premolars were randomly assigned to five groups. The teeth in groups 2 through 5 were immersed in a demineralising solution for 16 weeks. In groups 1 (control) and 2 (demineralised/control), conventional acid etching was used. In group 3, sodium hypochlorite (NaOCl) was applied on the enamel surface for 1 min after acid etching, and in group 4, Transbond Plus (3M Unitek, Monrovia, CA, USA) self-etching primer (SEP) was used. The teeth in group 5 were treated with 2% sodium fluoride (NaF) for 4 min before etching. After bracket bonding, the specimens were thermocycled, sealed with nail varnish, immersed in 0.5% basic fuchsine solution for 24 h and sectioned. Microleakage was measured under a stereomicroscope for the enamel-adhesive and adhesive-bracket interfaces of both occlusal and gingival sides.

Results

Demineralised teeth showed more microleakage at the enamel-adhesive interface on both occlusal and gingival sides compared to sound teeth, but the difference was not significant (P > 0.005). Treating the demineralised enamel with 5% NaOCl or Transbond Plus SEP was not effective in reducing microleakage. NaF treatment followed by acid etching of demineralised enamel resulted in significantly lower microleakage in most comparisons (P < 0.005).

Conclusions

The use of 2% NaF on hypomineralised enamel before the bracket bonding procedure is an effective way to decrease microleakage.     

Whole chromosome 17 loss in ovarian cancer

Chromosomal deletions, associated with the loss of normal function of tumour suppressor genes, have been identified in a variety of both familial and sporadic human cancers. Although the molecular pathology of ovarian cancer is not understood, several studies have reported deletions in chromosome 17 in ovarian tumours. We have used 13 restriction site polymorphic, microsatellite, and variable number tandem repeat markers to make a detailed analysis of chromosome 17 deletions in 12 benign and 19 malignant ovarian tumours. Two benign and 11 malignant tumours were informative for at least one marker on each arm of the chromosome. Loss of heterozygosity (LOH) was detected in both arms (by all informative markers) in 5 malignant tumours from four women (three with the disease at FIGO stage la). In a further bilateral ovarian tumour a partial LOH affecting 17q22-q25 was present in one ovary only. By contrast to a number of previous studies, none of the 19 malignant and 12 benign tumours showed ERBB2 (17q12ndash;22) amplification. The data presented show that the loss of a whole copy of chromosome 17 is a frequent and relatively early event in the development of some ovarian cancers. This suggests the possible involvement of multiple chromosome 17 loci in the pathogenesis of ovarian cancer. Equally plausible is that the loss of a whole chromosome copy could be the product of chromosomal instabilities induced by loss of the normal allele of tumour suppressors, such as TP53, located on this chromosome. © 1993 Wiley-Liss, Inc.     

Percutaneous vertebroplasty in symptomatic hemangioma versus osteoporotic compression fracture

Background:

Percutaneous vertebroplasty (PVP) is more commonly used for osteoporotic compression fractures (OCFs) and osteolytic vertebral body tumors. This study aimed to study the differences between OCFs and vertebral hemangiomas (VHs) treated with PVP.

Materials and Methods:

Between September 2007 and January 2010, we prospectively treated 28 consecutive patients of OCFs (43 recently symptomatic OCFs) and 24 cases of VHs (26 VHs). We used visual analogue scale (VAS) pain and Oswestry Disability Index (ODI) to evaluate the patients. The followup period in group 1 and 2 were 25.1 months (range 12 - 31 months) and 21.3 months (range 14 - 28 months), respectively. Comparison of means was carried out with the Chi Square Tests, t-test, and N Par-Test for multiple comparisons, whenever appropriate. The level of statistical significance was set at P < 0.05.

Results:

Following PVP the VAS score decreased to 4.57 and 4.17 in group 1 and 2, respectively. The ODI scores were 32.5% and 30%, respectively. This decrease in ODI scores lasted throughout the followup period.

Conclusions:

Although the preoperative scores were significantly different between group 1 and 2, there was no significant difference between two groups following the PVP.     

Long-term NaHS administration reduces oxidative stress and apoptosis in a rat model of left-side varicocele

The main aim of this study was to assay the testicular H₂S levels in the varicocele rat model and then to investigate the protective effects of NaHS on morphometric changes, sperm parameters, oxidative stress and apoptosis markers in rat's testis. D,L-propargylglycine (PAG) was administrated to show the effects of cystathionine γ-lyase enzyme (CSE) inhibition in the varicocele. Rats were assigned to four groups: (a) Sham, (b) varicocele, (c) varicocele + PAG and (d) varicocele + NaHS. Animals in varicocele + NaHS group received 30 µmol/L NaHS in drinking water for 56 days. In the varicocele + PAG group, animals received PAG 19 mg/kg twice a week. Morphometric assessment, oxidative stress markers, testicular H₂S levels, sperm parameters, TUNEL assay and expression of Bax/Bcl2 were evaluated at the end of experiment. Testicular H₂S levels were significantly decreased in varicocele group. NaHS significantly improved sperm parameters, morphometric characteristics and oxidative stress compared to varicocele group. Oxidative stress status deteriorated in the PAG group compared to the varicocele group. This study showed that a low testicular H₂S level might play a critical role in male infertility. Thus, NaHS administration may be a promising treatment strategy for male infertility in varicocele. In addition, CSE may not be the only important enzyme in testicular H₂S production.     

Mass smallpox vaccination and cardiac deaths, New York City, 1947

In April 1947, during a smallpox outbreak in New York City (NYC), more than 6 million people were vaccinated. To determine whether vaccination increased cardiac death, we reviewed NYC death certificates for comparable periods in 1946, 1947, and 1948 (N = 81,529) and calculated adjusted relative death rates for the postvaccination period. No increases in cardiac deaths were observed.     

Radiolabeled antibody therapy in non-Hodgkins lymphoma: radiation protection, isotope comparisons and quality of life issues

Anti-CD20 antibodies radiolabeled with I-131 tositumomab (Bexxar) or Y-90-Ibritumomab tiuxetan (Zevalin), are similarly efficacious in treating chemotherapy-refractory non-Hodgkin's lymphoma. The relative merits of both radioimmunoconjugates with respect to practical issues, including radiation exposure risk, the advantages and disadvantages of the respective isotopes and other parameters that could affect a patient's quality of life are also important. I-131-labeled antibody treatment often requires inpatient hospitalization due to the inherent risk of exposure from gamma emissions, and patients and families should follow detailed instructions to prevent undue exposure. Other issues relevant to patients and medical staff include: (1) the need for dosimetry to calculate effective therapeutic doses of I-131-labeled anti-B1 (Bexxar) compared with the lack of correlation of dosimetry with marrow toxicity for IDEC-Y2B8 (Zevalin), (2) determining the acute and long-term toxic effects of each agent, (3) time commitments for nuclear medicine staff and patients along with the relative ease of administration, and (4) cost considerations. A more challenging future issue will be to determine the optimal use of Bexxar and Zevalin alone and in combination in ways that will significantly affect patient outcome without compromising quality of life. The recent demonstration of significant response rates in patients having chemotherapy-refractory Non-Hodgkin's Lymphoma (NHL) using both on I-131- and Y-90-labeled anti-CD20 antibodies with minimal toxicity has stimulated comparison of I-131 tositumomab (Bexxar) and Ibritumomab tiuxetan (Zevalin) in terms of radiation safety requirements, the advantages and disadvantages of both radionuclides, and quality-of-life (QOL) issues. Therefore, in this review, we attempt to compare the relative merits of (Bexxar and Zevalin) and address important practical considerations that may influence patient and physician choices regarding treatment using these agents.     

Dental implant treatment in diabetic patients

The purpose of the present study was twofold: (1) to investigate how many diabetic patients and types of cases that are treated with dental implants in our clinic; and (2) assess the outcome of such treatment. Medical records from 782 patients were examined in patients treated by the Br?nemark method for partial or total edentulism with implant supported bridges. From these records, 25 patients (3.2%) with diabetes before implant treatment (136 implants) were identified and further studied with respect to age, gender, type of diabetes, treated jaw, degree of edentulism, bone graft, implant survival, periimplant inflammation, bleeding on probing, and radiographic bone loss. Furthermore, the patients' opinion about the outcome of the treatment was registered. The implant success rate was 96.3% during the healing period and 94.1% 1 year after surgery. Of all 38 bridges, one was lost. Few complications occurred and all patients, except for one, were satisfied with the treatment. Today, diabetic patients are being treated successfully for all types of edentulism, including bone-grafting treatment. Diabetics that undergo dental implant treatment do not encounter a higher failure rate than the normal population, if the diabetics' plasma glucose level is normal or close to normal as assessed by personal interviews.     

Comparison of the effects of simultaneous administration of vitamin C and omega-3 fatty acids on lipoproteins,apo A-I,apo B,and malondialdehyde in hyperlipidemic patients

BACKGROUND: Control of hyperlipidemia is vital in patients with cardiovascular disease (CVD). Omega-3 fatty acids (n-3FAs) have desirable effects on serum triglyceride (TG) levels, thrombosis, and arrhythmia, but lead to increases in serum low-density lipoprotein (LDL) and apo-B as well. OBJECTIVE: To determine and compare the effects of administration of n-3FAs, vitamin C (VitC) and n-3FAs + VitC on the serum levels of LDL, apoB, other serum lipids, and malondialdehyde (MDA). The present study was performed in Tehran University of Medical Sciences from 2000 to 2001. DESIGN: In a double-blind, placebo trial of parallel design, 68 hyperlipidemic patients [total cholesterol (TC) and TG greater than 200 mg/dL] were randomly assigned to receive daily 500 mg VitC, 1 g n-3FAs, 500 mg VitC + 1 g n-3FAs, or placebo (control) for 10 weeks. Fasting blood samples were collected at the beginning and at the end of the period. TG, TC, LDL-cholesterol-C (LDL-C), and high-density lipoprotein-cholesterol (HDL-C) were measured enzymatically, VitC and MDA colorimetrically, and apo-B and apo-A-I immunoturbidometrically. The pattern of food consumption, socio-economic, and anthropometric indices were determined; there was no significant change in these indices during the study. RESULTS: There was a significant difference in the blood VitC level at the end of the study in comparison to the initial value in the VitC (p = 0.001) and VitC + n-3FAs (p = 0.027) groups. Similarly, the serum TG level at the end of study was significantly different from the initial value in the n-3FAs group (p = 0.002) and also from the final value in the control group (p = 0.013). In the VitC group, there was a significant decrease in TC (p = 0.004), apo-B (p = 0.005), and MDA (p = 0.015) at the end of study as compared to the respective initial values. There was also a significant increase in blood VitC compared to the control value (p = 0.018) and a significant decrease in MDA compared to the n-3FAs group (p = 0.034). At the end of study, in the n-3FAs group, there was a significant (p = 0.04) and a marginally significant decrease (p = 0.05), respectively, in TG/HDL and apo-B levels as compared to the initial values, and the TG/HDL ratio showed a significant decrease as compared to the control group (p = 0.047). CONCLUSION: Simultaneous administration of n-3FAs and VitC had no beneficial effects on the lipid profile of hyperlipidemic patients, but 1 g purified n-3FAs daily for 10 weeks is a beneficial supplement for decreasing TG without any increase in LDL-C, apo-B or MDA. Administration of 500 mg VitC for more than 10 weeks might decrease significantly TC and apo-B in hyperlipidemic patients.