Relationship between cumulative radiation dose and salivary gland uptake associated with radioiodine therapy of thyroid cancer

AIM: To estimate the individual absorbed dose to the parotid and submandibular salivary glands in radioiodine therapy and its dependence from the previous cumulative therapy. METHODS: Fifty-five patients with differentiated thyroid carcinoma after thyroidectomy received 1-21 GBq (131)I using single activities of 1-6 GBq. The patients were stratified according to the cumulative activities into low-activity (1-2 GBq), middle-activity (3-7 GBq), and high-activity groups (9-21 GBq). The time-activity curves over the respective salivary glands were derived from multiple static calibrated images measured for each patient up to 48 h after ingestion of the radioiodine therapy capsule with a gamma camera. Manually drawn regions of interests were used to determine the background activities and the activities arising from the salivary glands. The gland volumes were determined by ultrasonography using appropriate volume models. RESULTS: The median absorbed dose per administered activity of each single parotid and submandibular gland was about 0.15 Gy.GBq (range, 0.1-0.3 Gy.GBq(-1)) and 0.48 Gy.GBq(-1) (range, 0.2-1.2 Gy.GBq(-1)), respectively. The maximum uptake of both gland types was significantly lower for the high-activity than for the low-activity groups and correlated with the mean cumulative administered activity of the activity groups. CONCLUSION: The iodine uptake of salivary glands is significantly reduced, whereas the absorbed dose per administered (131)I activity was not significantly decreased during the course of therapy. Comparing the well-known dose-effect relationships in external radiation therapy, the absorbed dose per administered (131)I activity is too low to induce comparable radiation damage, suggesting an inhomogeneous distribution of (131)I in human salivary glands.     

Quantitative evaluation of proximal tooth movement effected by wedging: a pilot study

The major purpose of this pilot study was to develop a method to accurately measure proximal tooth movement. A preliminary clinical evaluation of anterior and posterior tooth movement was performed with five patients. The patients were carefully chosen to eliminate as many variables as possible. The controlled patient criteria included periodontal health, proximal contacts, the age of the patients, and the teeth selected for anterior and posterior displacement. The small sample size dictates that additional experimentation must be performed before definitive conclusions can be drawn.     

Effect of hydrosalpinx fluid on secretion of trophoblastic matrix metalloproteinases

OBJECTIVE: To determine if hydrosalpinx fluid affects trophoblastic metalloproteinases (MMPs) secretion. DESIGN: Measurement of the effect of hydrosalpinx and peritoneal fluids (as controls) added to the medium on the MMPs secreted by cytotrophoblastic cells. SETTING: Academic research center. PATIENT(S): Five samples of hydrosalpinx fluid were obtained at the time of ovocyte retrieval. Three samples of peritoneal fluids were collected at laparoscopic sterilization. MAIN OUTCOME MEASURE(S): The concentration and activity of MMP-2 and MMP-9, the concentration of the tissue inhibitor of metalloproteinases (TIMP-1), and the total gelatinolytic activity of the cytotrophoblastic cells were measured in the culture medium. RESULT(S): Hydrosalpinx significantly stimulated MMP-2, MMP-9, and TIMP-1. The net result was a significant stimulation of the total gelatinolytic activity. Peritoneal fluids increased MMP-2, MMP-9, and TIMP-1 concentrations, but the total gelatinolytic activity was not modified. CONCLUSION(S): In contrast to peritoneal fluids, hydrosalpinx stimulates the total gelatinolytic activity of cytotrophoblastic cells. This might indicate that the effect of hydrosalpinx on implantation rates may not be due to an inhibition of the capacity of an embryo to invade the endometrium. However, the stimulatory effect of hydrosalpinx on the net gelatinolytic activity could partly explain the increased incidence of ectopic pregnancies that have been described in the presence of hydrosalpinx.     

Value of 124I-PET/CT in staging of patients with differentiated thyroid cancer

The aim of this study is to evaluate the clinical significance of ¹²⁴I positron emission tomography (PET) using a combined PET/CT tomograph in patients with differentiated thyroid carcinoma and to compare the PET/CT results with ¹³¹I whole-body scintigraphy (WBS), dedicated PET and CT alone. Twelve thyroid cancer patients were referred for diagnostic workup and entered complete clinical evaluation, including histology, cytology, thyroglobulin level, ultrasonography, fluorine-18 fluorodeoxyglucose (FDG)-PET, FDG-PET/CT and CT. Lesion-based evaluation showed a lesion delectability of 56, 87 and 100% for CT, ¹²⁴I-PET, and combined ¹²⁴I-PET/CT imaging, respectively. Lesion delectability of ¹³¹I-WBS was 83%. We conclude that ¹²⁴I-PET/CT imaging is a promising technique to improve treatment planning in thyroid cancer. It is particularly valuable in patients suffering from advanced differentiated thyroid cancer prior to radio-iodine therapy and in patients with suspected recurrence and potential metastatic disease.     

Entropic DNA

The presence of mobile genetic elements without apparent biological function within genomes requires explanation. It is argued that consideration of DNA as an open thermodynamic system leads to the simple hypothesis that mobile genetic material increases the internal entropy thereby lowering the free energy of the DNA relative to DNA of the same size. This phenomenon enhances the survival of such sequences by simple structural stabilization. The consequences of this idea are discussed in terms of the proposed Bekenstein limit to the entropy to energy ratio of thermodynamic systems and biological entropy/information flow.     

Mutation screening of the BTK gene in 56 families with X-linked agammaglobulinemia (XLA): 47 unique mutations without correlation to clinical course

OBJECTIVES: To determine the utility of single-stranded conformation polymorphism (SSCP) analysis for mutation screening in the BTK (Bruton's tyrosine kinase) gene, we investigated 56 X-linked agammaglobulinemia (XLA) families. To obtain genotype/ phenotype correlations, predicted protein aberrations were correlated with the clinical course of the disease. PATIENTS: This study included 56 patients with XLA, with or without a positive family history, who were diagnosed on the basis of their clinical features, low peripheral B-cell count, and low immunoglobulin levels. Ten patients with isolated hypogammaglobulinemia and 50 healthy males served as controls. METHODS: SSCP analysis was performed for the entire BTK gene, including the exon-intron boundaries and the promoter region. Structural implications of the missense mutations were investigated by molecular modeling, and the functional consequences of some mutations also were evaluated by in vitro kinase assays and Western blot analysis. RESULTS: We report the largest series of patients with XLA to date. All but 5 of the 56 index patients with XLA screened with SSCP analysis showed BTK gene abnormalities, and in 2 of the 5 SSCP-negative patients, no BTK protein was found by Western blot analysis. There were 51 mutations, including 37 novel ones, distributed across the entire gene. This report contains the first promoter mutation as well as 14 novel missense mutations with the first ones described for the Tec homology domain and the glycine-rich motif in the SH1 domain. Each index patient had a different mutation, except for four mutations, each in two unrelated individuals. This result supports the strong tendency for private mutations in this disease. No mutations were found in the controls. CONCLUSIONS: Our results demonstrate that molecular genetic testing by SSCP analysis provides an accurate tool for the definitive diagnosis of XLA and the discrimination of borderline cases, such as certain hypogammaglobulinemia or common variable immunodeficiency patients with overlapping clinical features. Genotype/ phenotype correlations are not currently possible, making prediction of the clinical course based on molecular genetic data infeasible.