Dosimetric evaluation of the effect of dental implants in head and neck radiotherapy.

OBJECTIVE: The aim of the study was to examine the dose enhancement from scattered radiation at bone-dental implant interfaces during simulated head and neck radiotherapy. STUDY DESIGN: Four cylindrical titanium dental implants with 3 different sizes and lengths were implanted into a human mandible in 4 different positions. Ionization measurements for 6 MV X, 25 MV X, and Co-60 gamma rays were done. Thermoluminescent dosimeter (TLD 100 ) chips were used to measure radiation dose enhancement due to the scattered electrons from titanium and electronic disequilibrium at the tissue-metal interface. RESULTS: The results showed that for Co-60, there is a 21% maximum increase in dose to alveolar mandibular bone at the close proximity to the titanium. For 6-MV x-rays the dose enhancement increase was almost the same or slightly lower than for Co-60, while for 25-MV high-energy x-rays, dose enhancement was lower than that of others. This increase in dose enhancement fell off rapidly and became insignificant at 2 mm from the interface. CONCLUSION: Total dose that may lead to osteoradionecrosis risk of the mandible is slightly but not significantly affected by the scattered dose of the dental implants of lower jaw in the radiation field exposed to 3 different radiation beams.     

Is there any relationship between human leucocyte antigen class II and chronic urticaria? (chronic urticaria and HLA class II)

The Human Leukocyte Antigen (HLA) typing of large groups of patients with various autoimmune diseases has demonstrated that some HLA alleles occur at higher frequencies in specific diseases than in the general population. Chronic urticaria has been shown to have an autoimmune basis by a previous study which found an association between chronic urticaria and specific HLA groups. We investigated the HLA subtypes of Turkish chronic urticaria patients. For this purpose 42 Turkish patients with chronic urticaria and 115 healthy controls were typed for HLA-DR and DQ by PCR-SSP (Polymerase Chain Reaction Sequence Specific Primers) low resolution DNA technique. We found an increased frequency of DR4 (42.9%, p=0.01) in chronic urticaria patients in comparison with that in healthy controls. This study supports the hypothesis that HLA alleles may be involved in the pathogenesis of chronic urticaria and that they appear to be directly involved in the initiation of the immune response.     

Prognostic and immunohistochemical validation of the capella classification of pancreatic neuroendocrine tumours: an analysis of 82 sporadic cases

AIMS: To study the clinical outcome of 82 cases of pancreatic neuroendocrine tumours classified according to the recent histological and prognostic classification of Capella. METHODS AND RESULTS: Eighty-two surgical cases of pancreatic neuroendocrine tumours were examined histologically with immunohistochemical staining of paraffin sections using streptavidin-biotin complex and application of antibodies against chromogranin A and 10 hormonal peptides. Classification in four groups correlated with long follow-up and outcome of these cases. Histological examination showed 30 group I, four group II, 41 group III and seven group IV tumours. Twenty-one (70%) of group I tumours were insulinomas, whereas 25% of group III tumours were glucagonomas and 25% were unclassified. Most group IV tumours were unclassified, showing no immunohistochemical staining with any of the 10 hormonal peptides tested. Outcome was clearly correlated with tumour group. Among the 14 patients who died of the disease, four had group IV and 10 group III tumours. Thus, unclassified asymptomatic tumours without immunohistochemical staining had a poorer prognosis than asymptomatic tumours with staining. CONCLUSION: This study validates the Capella classification as easy to apply and useful in predicting clinical outcome.     

Andrology: Pentoxifylline-enhanced acrosome reaction correlates with fertilization in vitro

To evaluate the possible effect of pentoxifylline on the acrosomereaction (AR) and its correlation with in-vitro fertilization(IVF), sperm samples obtained from 51 patients who underwentIVF treatment were studied. Acrosome reactions were evaluatedas spontaneous, pentoxifylline-treated and calcium ionophore(A23187) induced, before and after treatment. The correlationof AR with fertilization in vitro in spermatozoa pre-treatedwith pentoxifylline was sought. In cases with failure or verylow fertilization rate (10%) in their previous trials, spermatozoaafter swim-up were treated before insemination. Spontaneousacrosome loss remained low even after treatment (mean ±SD: 8.18 ± 1.74%). Response to A23187 was enhanced significantly(P < 0.001) by pre-treatment with pentoxifylline in 33 controlcases (group A) in which fertilization in vitro was previouslysuccessful without this treatment. Patients with at least twoepisodes of failed fertilization were divided into two groups.In 11 cases (group B), the IVF rate was improved significantly(P < 0.001) by the treatment. This was not observed in sevencases (group C) in which the treatment induced no increase inIVF rate. We achieved nine (27.3%) pregnancies in group A andfive (45.4%) pregnancies in group B. This study demonstratedthat pentoxifylline enhanced A23187 induced the acrosome reactionand this effect was correlated with improvement in IVF rate.     

Survival rates during the first trimester of multiple gestations achieved by ICSI: a report of 1448 consecutive multiples

BACKGROUND: The purpose of this study was to determine the rate of spontaneous gestational sac loss during the first trimester in women achieving multiple pregnancies by ICSI. METHODS: A retrospective analysis was performed of 1448 consecutive multiple pregnancies conceived by ICSI. RESULTS: Of the cohort of 1448 pregnancies, twin gestations constituted 59.6% (864), triplets 30.2% (438) and quadruplets 10.0% (146). During the first trimester, 69 (4.7%) patients miscarried, while 179 (12.3%) continued their pregnancies and had fewer gestational sacs at the end of the first trimester than at the beginning. The overall loss rate of any gestational sac during the first trimester in these multiple pregnancies was 10.1%. There was a significant difference in the frequency of spontaneous reduction to twin or singleton pregnancies in the first trimester between women carrying triplets (11.7%) and those carrying quadruplets (3.5%) [P = 0.004; odds ratio (OR) 3.5; 95% confidence interval (CI) 1.3-9.1]. The frequency of gestational sac loss was significantly greater among women >35 years old (20.9%) than in women less than 35 years old (15.9%) (P = 0.03; OR 1.4; 95% CI 1.0-1.9). CONCLUSION: In multiple pregnancies there is a significant risk of spontaneous loss of any embryo during the first trimester. These findings should be considered prior to any decision about selective embryo reduction.     

The effects of vitamin A, pentoxyfylline and methylprednisolone on experimentally induced amyloid arthropathy in brown layer chicks.

The effects of vitamin A, pentoxyfylline and methylprednisolone on experimentally induced amyloid arthropathy were investigated. In this study, 175 1-day-old brown layer chicks were used. Throughout the study Group II (vitamin A) received high doses of vitamin A (75,000 IU/kg), whereas Group I (negative control), Group III (positive control), Group IV (pentoxyfylline) and Group V (methylprednisolone) received normal levels of vitamin A in the diet. At the fifth week, the experimental Groups II, III, IV and V were injected with Freund's adjuvant intra-articularly to induce amyloid arthropathy. Group IV received pentoxyfylline and Group V received methylprednisolone (10 mg/kg, intramuscularly) once. Joint and blood samples were examined 13 weeks after the injections. The values in Groups I, II, III, IV and V, respectively, were as follows: amyloid arthropathy formation (%), 0, 100, 87, 76, 66; serum amyloid A (ng/ml), 166+/-17, 607+/-40, 423+/-39, 342+/-27, 293+/-22; serum retinol (microg/dl): 59.75+/-3.8, 42.72+/-3, 59.24+/-3.6, 102+/-9.1, 101.3+/-12.3; heterophil/lymphocyte ratio: 0.504, 0.75, 0.75, 0.087, 0.44. In conclusion, it was observed that vitamin A enhanced the development of amyloid arthropathy and there were positive associations between amyloidosis, increased levels of serum amyloid A and increased numbers of tissue infiltrating macrophages. Methylprednisolone had a more successful inhibitory effect on amyloid arthropathy than pentoxyfylline.     

Effects of vitamin E supplementation on oxidative stress in streptozotocin induced diabetic rats: investigation of liver and plasma

This experimental study was designed to investigate the effects of vitamin E supplementation, especially on lipid peroxidation and antioxidant status elements 3/4 namely, glutathione (GSH), CuZn superoxide dismutase (CuZn SOD), and glutathione peroxidase (GSH Px), both in blood and liver tissues of streptozotocin (STZ) diabetic rats. The extent to which blood can be used to reflect the oxidative stress of the liver is also investigated. In diabetic rats, plasma lipid peroxide values were not significantly different,from control,whereas erythrocyte CuZn SOD (p < 0.01), GSH Px (p < 0.001) activities and plasma vitamin E levels (p < 0.001), were significantly more elevated than controls. Vitamin E supplementation caused significant decreases of erythrocyte GSH level (p < 0.01) in control rats and of erythrocyte GSH Px activity (p < 0.05) in diabetic rats. Liver findings revealed significantly higher lipid peroxide (p < 0.001) and vitamin E (p < 0.01) levels and lower GSH (p < 0.001), CuZn SOD (p < 0.001) and GSH Px (p < 0.01) levels in diabetic rats. A decreased hepatic lipid peroxide level (p < 0.01) and increased vitamin E/lipid peroxide ratio (p < 0.001) were observed in vitamin E supplemented, diabetic rats. A vitamin E supplementation level which did not cause any increase in the concentration of the vitamin in the liver or blood, was sufficient to lower lipid peroxidation in the liver. Vitamin E/lipid peroxide ratio is suggested as an appropriate index to evaluate the efficiency of vitamin E activity,independent of tissue lipid values. Further, the antioxidant components GSH, GSH Px and CuZn SOD and the relationships among them, were affected differently in the liver and blood by diabetes or vitamin E supplementation.