Childhood thyroid cancer. Characteristics and long-term outcome in children irradiated for benign conditions of the head and neck

OBJECTIVE: To determine the characteristics and long-term outcome of radiation-induced thyroid cancer in children. DESIGN: Retrospective review of a cohort of 4296 irradiated patients who received childhood radiation treatment to the head and neck area at the same hospital. PATIENTS: Forty-one children who were younger than 20 years when thyroid cancer developed in them and 77 adults in whom thyroid cancer developed. All 118 cases were diagnosed before 1974 and were followed up for a median of 19.4 years. RESULTS: Children presented with clinically palpable lymph nodes more often than adults (30.7% vs 15.1%, P = .05) and had more recurrences (39% vs 16%, P = .05). Despite these frequent recurrences, only one patient (an adult) died of thyroid cancer. Seventy percent of the recurrences occurred during the first 10 years of follow-up, but recurrences continued after 20 years. The adults had previously identified factors that predicted the risk of recurrences, but none could be identified in the children. CONCLUSION: The presentation and relatively good outcome of radiation-induced thyroid cancer in children is similar to that in nonirradiated children. Frequent and late recurrences call for lifelong follow-up.     

Structural plasticity in RNA and its role in the regulation of protein translation in coliphage Q beta

We have analyzed both conformational and functional changes caused by two large cis-acting deletions (delta 159 and delta 549) located within the read-through domain, a 850 nucleotide hairpin, in coliphage Q beta genomic RNA. Studies in vivo show that co-translational regulation of the viral coat and replicase genes has been uncoupled in viral genomes carrying deletion delta 159. Translational regulation is restored in deletion delta 549, a naturally evolved pseudorevertant. Structural analysis by computer modeling shows that structural features within the read-through domain of delta 159 RNA are less well determined than they are in the read-through domain of wild-type RNA, whereas predicted structure in the read-through domain of evolved pseudorevertant delta 549 is unusually well determined. Structural analysis by electron microscopy of the genomic RNAs shows that several long range helices at the base of the read-through domain, that suppress translational initiation of the viral replicase gene in the wild-type genome, have been destabilized in delta 159 RNA. In addition, the structure of local hairpins within the read-through region is more variable in delta 159 RNA than in wild-type RNA. Stable RNA secondary structure is restored in the read-through domain of delta 549 RNA. Our analyses suggest that structure throughout the read-through domain affects the regulation of viral replicase expression by altering the likelihood that long-range interactions at the base of the domain will form. We discuss possible kinetic and equilibrium models that can explain this effect, and argue that observed changes in structural plasticity within the read-through domain of the mutant genomes are key in understanding the process. During the course of these studies, we became aware of the importance of the information contained in the energy dot plot produced by the RNA secondary structure prediction program mfold. As a result, we have improved the graphical representation of this information through the use of color annotation in the predicted optimal folding. The method is presented here for the first time.     

Impairment of energy metabolism and excitotoxic cell death in Huntington disease

The gene for Huntington's disease is widely expressed in brain and yet the illness is characterized pathologically by a distinct regional pattern of cell death. Various theories for this selective vulnerability have been offered but the most compelling remains that of abnormal energy metabolism. These issues are reviewed.     

Update on the use of percutaneous nephrostomy/balloon dilation for the treatment of renal transplant leak/obstruction

PURPOSE: Retrospective evaluation of the efficacy of percutaneous nephrostomy and nephroureteral stent placement for treatment of post-transplant ureteral leak, and percutaneous nephrostomy and balloon dilation for treatment of post-transplant ureteral obstruction. PATIENTS AND METHODS: Data were reviewed for all patients who underwent percutaneous therapy for complications after renal transplantation between January 1985 and June 1995. A total of 61 patients with complications (leak, n = 17; obstruction, n = 44) had been treated. Patients underwent percutaneous nephrostomy followed by antegrade placement of a nephroureteral stent. In addition, all patients with obstruction also underwent ureteral balloon dilation. Follow-up ranged from 9 weeks to 24 months. Positive outcome was defined as nonsurgical closure of leak, significant improvement in renal function, and removal of the nephroureteral stent with maintenance of stable renal function. RESULTS: Regarding ureteral leak, 10 of 17 patients (59%) healed after treatment. Seven patients (41%) did not respond and went on to surgical repair. All patients with early (n = 13) ureteral obstruction (< 3 months after transplantation), had improved renal function (P < .025). Sixty-two percent of patients with early obstruction were cured (tube out with stable renal function) and 38% went to surgery for ureteral repair. In patients with late (n = 31) obstruction (> 3 months after transplantation), renal function improved in only 58% (P < .01). Only 16% of patients with late obstruction were cured (tube out with stable renal function). Ureteral obstruction was persistent in the remaining patients and did not respond to multiple balloon dilations. All complications were minor and included 23 of 61 (38%) patients with urinary tract infections and nine of 61 (14%) patients with limited hematuria. CONCLUSION: Percutaneous nephrostomy is very effective in improving renal function in patients with early obstruction. It is moderately successful in treating ureteral leak. Ureteral balloon dilatation is moderately effective for treatment of obstruction in the early (< 3 months) postoperative period. However, balloon dilation is minimally successful in curing ureteric obstruction occurring more than 3 months after transplantation.     

Peptide amidating activity in human bronchoalveolar lavage fluid

Monitoring respiratory epithelial biology may reveal individuals with incipient lung cancer. The expression of neuroendocrine (NE) markers in pulmonary epithelium is thought to be central to lung development, repair of injury and may contribute to carcinogenesis. In this study, we evaluate several candidate NE markers to determine the feasibility of prospective analysis of clinical specimens. The potential NE markers include the enzyme L-DOPA decarboxylase (DDC), the neuropeptide gastrin releasing peptide (GRP), and peptidyl-glycine alpha-amidating monooxygenase (PAM), the bifunctional enzyme responsible for the final bioactivation step of many neuropeptides. A comparison of PAM activity and DDC levels in 30 lung cancer cell lines indicated that peptide amidating activity may be an indicator of NE status. Bronchoalveolar lavage (BAL) fluid from subjects at risk of developing second primary lung cancer and from volunteers was obtained. The activity of the first PAM enzyme, peptidylglycine alpha-hydroxylating monooxygenase (PHM), ranged from not detectable to 507 pmol/h/mg protein in 57 specimens. The second PAM enzyme, peptidylamidoglycolate lyase (PAL), ranged from not detectable to 414 pmol/h/mg protein in 56 specimens. Using cluster analysis by the average linkage method, a group of enzyme values with PHM greater than 230 pmol/h/mg protein was determined. Long-term follow-up of these patients for new second primary lung cancers may help to determine the potential predictive value of PAM detected in the BAL fluid.     

The Second Canadian Gastroesophageal Reflux Disease Consensus: moving forward to new concepts

Gastroesophageal reflux disease (GERD) is a disease with serious consequences that may result in significant impairment in quality of life and disease morbidity. Across all grades of severity of symptoms and severity of underlying esophageal disease, proton pump inhibitors (PPIs) provide therapeutic gains over prokinetics (PKs) or H2 receptor antagonists (H2RAs). The potential cost effectiveness of using medications with higher acquisition costs that may lower health care costs overall is often disregarded when conducting cost comparisons with medications having lower 'up-front' costs. Limiting therapy to less effective agents condemns many patients to protracted suffering, repeated physician visits and needless reinvestigation of symptoms that could have been resolved by appropriate initial therapy. Based on current data, use of any classification of symptom severity as a basis for selecting one class of therapeutic agents over another for first line therapy (i.e. PKs, H2RAs for 'mild' GERD, versus a PPI for 'severe' disease) is unwarranted.     

The prospects for using the genetically engineered surface antigen of the hepatitis B virus (HBsAg) expressed by recombinant poxvirus strains as the basis for vaccines against hepatitis B

The use of a recombinant poxvirus (RPV) strain, expressing HBsAg in the process of reproduction in different bioreactor systems under stationary and bioreactor conditions of cultivation, made it possible to obtain highly purified HBsAg. The identity and purity of HBsAg was confirmed by the analysis of its amino acid composition, SDS electrophoresis in polyacrylamide gel, electron microscopy and high-performance liquid chromatography. Good prospects of the use of RPV-expressed gene engineering HBsAg as the basis vaccines against hepatitis B was demonstrated in 10 experimental batches of vaccine. All batches of the preparation had pronounced immunogenicity and were safe and nontoxic in animal experiments. The ID50 of experimental batches did not exceed 211 ng/ml, which, according to the data of comparative experiments, was lower than, or equal to, corresponding values of analogous foreign commercial preparations, based on plasma or yeast HBsAg.     

Leptin levels do not change acutely with food administration in normal or obese subjects, but are negatively correlated with pituitary-adrenal activity

Modern liver surgery is based upon deep knowledge of the surgical anatomy of the liver and improvements with ultrasounds imaging techniques have provided multidimensional interpretations of the liver anatomy intraoperatively. The technical advances with real-time scanning combined with the pioneering efforts of the Japanese liver surgeons have permitted the dynamic adaptation of the functional liver anatomy to the real anatomy, thus intimately aiding in segment oriented anatomical resection. Intraoperative ultrasound afford several advantages such as viewing the internal anatomy in direct relationship to the surface landmarks under the probe, enabling higher frequencies resulting in greater image resolution. The utilization of intraoperative ultrasound can modify the tactics involved with resection of both primary and metastatic liver tumours. The routine use of intraoperative ultrasound is strongly advocated since more complex procedures can be performed safely since the surgeon proceeds with complete knowledge of the real liver anatomy when deciding the feasibility and extent of liver resection.