Nitric oxide/cGMP signaling inhibits TSH-stimulated iodide uptake and expression of thyroid peroxidase and thyroglobulin mRNA in FRTL-5 thyroid cells.

OBJECTIVE: Nitric oxide (NO) induces morphological and functional alterations in primary cultured thyroid cells. The aim of this paper was to analyze the direct influence of a long-term exposition to NO on parameters of thyroid hormone biosynthesis in FRTL-5 cells. DESIGN: Cells were treated with the NO donor sodium nitroprusside (SNP) for 24-72 h. MAIN OUTCOME: SNP (50-500 micromol/L) reduced iodide uptake in a concentration-dependent manner. The inhibition of iodide uptake increased progressively with time and matched nitrite accumulation. SNP inhibited thyroperoxidase (TPO) and thyroglobulin (TG) mRNA expression in a concentration-dependent manner. SNP enhanced 3',5'-cyclic guanosine monophosphate (cGMP) production. 3',5'-cyclic adenosine phosphate (cAMP) generation was reduced by a high SNP concentration after 48 h. 8-Bromoguanosine 3',5'-cyclic monophosphate (8-Br-cGMP), a cGMP analog, inhibited iodide uptake as well as TPO and TG mRNA expression. The cGMP-dependent protein kinase (cGK) inhibitor KT-5823 reversed SNP or 8-Br-cGMP-inhibited iodide uptake. Thyroid-stimulating hormone pretreatment for 24-48 h prevented SNP-reduced iodide uptake although nitrite levels remained unaffected. CONCLUSION: These findings favor a long-term inhibitory role of the NO/cGMP pathway on parameters of thyroid hormone biosynthesis. A novel property of NO to inhibit TPO and TG mRNA expression is supported. The NO action on iodide uptake could involve cGK mediation. The long-term inhibition of steps of thyroid hormonogenesis by NO could be of interest in thyroid pathophysiology.     

Applying new clinicopathological characteristics to prognostication in advanced thyroid carcinoma

In the February 2011 issue of Endocrine-Related Cancer, Deandreis et al. reported that increased FDG uptake was prognostic in patients with metastatic thyroid cancer. Fludeoxyglucose-positron emission tomography (FDG-PET) is routinely used in the staging and follow-up of patients with cancer. This study gives further evidence for the role of FDG-PET scanning in metastatic thyroid cancer, especially to identify patients with aggressive disease requiring systemic therapy.     

Eleven novel mutations in the factor VIII gene from Brazilian hemophilia A patients

The molecular characterization of the mutations in hemophilia A patients is hampered by the large size of the factor VIII gene and the great heterogeneity of mutations. In this study, we have performed a protocol involving multiplex polymerase chain reaction in which 19 exons were amplified in four different combinations followed by nonradioactive single-strand conformational polymorphism (SSCP) to screen for mutations. Southern blotting was used to detect inversion of the factor VIII gene resulting from recombination between copies of the gene A (F8A) located in intron 22 of the factor VIII gene and two copies close telomeric region of X chromosome. Forty-two hemophilia A patients (21 with severe and 21 with mild-to-moderate disease) were studied. The inversion of factor VIII occurred in 13 of 21 patients affected by severe hemophilia A. One patient showed a large extra band in addition to the three bands observed after Southern blotting with the F8A probe. An abnormal electrophoretic pattern of SSCP was detected in 85% and 50% of the patients affected by mild-to-moderate and severe disease, respectively. Sixteen different mutations were identified. Eleven mutations were novel and comprised 9 point mutations and 2 small deletions. This study shows that the methodology used is safe and rapid and has potential for detecting almost all of the genetic defects of the studied hemophilia A patients.     

Detection of the hemoglobin E mutation using the color complementation assay: application to complex genotyping

The color complementation assay (CCA) is a method of allele-specific DNA amplification by which competitive priming and extension of fluorescently labeled oligonucleotide primers determine the color of DNA amplification product. This diagnostic method precludes the need for radioisotopes, electrophoresis, and multiple high-stringency reaction conditions. The multiplicity of mutant globin genes present in Southeast Asians complicates clinical diagnosis and underscores the importance of DNA-based diagnostic methods. We have applied CCA to distinguish beta A and beta E alleles. Competing 15mer primers were a fluorescein-labeled complement to beta A and a rhodamine-labeled complement to beta E, identical except for their central nucleotides. A common unlabeled primer was used to amplify DNA product, the color of which was determined by the perfectly complementary primer. Color photography and spectrofluorometry, as well as a method of black-white photography that we developed to distinguish fluorescein- and rhodamine- labeled DNA, were used to record results. We applied CCA to define the complex genotype of a Thai woman with thalassemia intermedia, 96% HbE, and 4% HbF whose possible genotypes included several permutations of alpha-thalassemia, beta-thalassemia, and beta E genes. zeta-Globin gene mapping of DNA doubly digested with Bg/II and Asp 718 showed the -alpha 3.7/--SEA genotype, and CCA confirmed homozygous beta E/beta E. The CCA is useful for diagnosing the compound hemoglobin genotypes of Southeast Asians and could be applied also to prenatal diagnosis in this population.     

Effects of intensive induction chemotherapy for extensive-disease small cell bronchogenic carcinoma in protected environment-prophylactic antibiotic units

Fifty-five patients with extensive-disease small cell bronchogenic carcinoma received three courses of intensive, inpatient, remission induction chemotherapy in (25 patients) or out (30 patients) of protected environment-prophylactic antibiotic (PEPA) units. Chemotherapy consisted of ECHO induction (E = epipodophyllotoxin VP-16-213; C = cyclophosphamide; H = hydroxydaunorubicin; O = Oncovin) and PRIME maintenance (PR = procarbazine; I = ifosfamide; ME = methotrexate). All evaluable patients (22 in the protected environment group and 26 in the control group) had a complete (50 percent in the protected environment group and 54 percent in the control group) or partial (50 percent in the protected environment group and 46 percent in the control group) remission. Median response and survival durations for both treatment groups were similar. The median survival duration of patients with a complete remission favored the protected environment group (16.5 versus 12.67 months; p = 0.20). Two patients (one from each group) are alive and disease-free for more than four years. Myelosuppression was intense and more pronounced in the protected environment group (p ≤ 0.01). Infectious complications were less common in patients receiving intravenous prophylactic antibiotics and in those treated with intravenous antibiotics in PEPA units (p ≤ 0.04). There were no treatment-related deaths, although treatment might have contributed to the death of three patients in the protected environment group and four in the control group. The administration of intensive ECHO induction chemotherapy to patients with extensive small cell bronchogenic carcinoma produced a high complete remission rate, although there was no significant long-term survival advantage over a program of less intensity. The administration of intravenous prophylactic antibiotics and the use of PEPA units significantly reduced the infectious morbidity of chemotherapy.     

Association between diabetes and nonretention of root filled teeth: a systematic review and meta‐analysis

Previous studies have found an association between the outcome of root canal treatment (RCT) and diabetic status. This systematic review and meta‐analysis aimed to analyse the potential relationship between diabetes and the occurrence of extracted root filled teeth (RFT). The clinical PICO question was as follows: in adult patients with RFT, does the absence or presence of diabetes influence the prevalence of RFT extraction? The key words used in the systematic search were as follows: (Diabetes OR Diabetes Mellitus OR Hyperglycaemia OR Diabetic) AND (Endodontic OR Endodontics OR Endodontic Treatment OR Root Canal Treatment OR Root Canal Preparation OR Root Canal Therapy OR Root Filled Teeth OR Endodontically Treated Teeth) AND (Extraction OR Retention OR Survival OR Success OR Failure OR Outcome). The primary outcome variable was odds ratio (OR) for the frequency of extracted RFT in diabetics and healthy subjects. The method of DerSimonian–Laird with random effects was used to calculate the overall OR. Three hundred titles were identified, and three studies achieved the inclusion criteria. Data from 54 936 root canal treatments, 50 301 in nondiabetic control subjects and 4635 in diabetic patients, were analysed. The calculated overall odds ratio (OR = 2.44; 95% CI = 1.54–3.88; P = 0.0001) implies that diabetics had a significantly higher prevalence of extracted RFT than healthy nondiabetic subjects. The results of available studies indicate a significant relationship between DM and increased frequency of nonretained root filled teeth. Diabetes mellitus should be considered an important preoperative prognostic factor in root canal treatment.