Detection of human papillomavirus in routinely processed biopsy specimens from laryngeal papillomas: evaluation of reproducibility of polymerase chain reaction and DNA in situ hybridization procedures

The frequency of human papillomavirus (HPV) in laryngeal papillomas varies largely among different studies. DNA in situ hybridization (ISH) has been the most widely used method for detection of HPV. The aim of this study was to compare the reproducibility and sensitivity of ISH with polymerase chain reaction (PCR) in 35 specimens of laryngeal papillomas routinely fixed in buffered or unbuffered formalin. Out of 12 specimens fixed in buffered formalin, 10 were positive for HPV 6/11 using ISH. The procedure was repeated three times and three specimens were positive only twice. Nine biopsies were positive for HPV using PCR with consensus primers (My 09/11) on dewaxed tissue without extracting DNA. In three repeated PCRs, the results were inconsistent in three samples. After DNA extraction, all 12 samples were positive with PCR. Of the 23 specimens fixed in unbuffered formalin, 14 were HPV-positive with ISH, while only one was positive with PCR. We concluded that PCR with My 09/11 consensus primers is a highly sensitive method for detection of HPV in laryngeal papillomas fixed in buffered formalin, but useless for samples fixed in unbuffered formalin. When DNA was extracted from the former type of fixed tissue, the results were highly reproducible. In contrast to PCR, ISH appeared to be less influenced by fixation procedure, but it was not as reproducible and sensitive as PCR. Negative results did not necessarily mean absence of HPV.     

Comparison of Markov model and fault tree approach in determining initiating event frequency for systems with two train configurations

This study explores the use of Markov models in some areas of systems analysis in which time evolution of the system may be a significant factor in influencing the system reliability or availability. Comparisons are made between the Markov models and the time-averaged fault tree models for determining support system failure initiating event frequency in a nuclear power plant, for both power and shutdown conditions. Factors affecting consistency between the fault tree approach and the Markov model approach are studied for systems with common two train configurations. A correlation is developed to estimate the ratio between initiator frequencies through both approaches for a two parallel component system. Insights are developed as to when time averaged and simplified fault tree models support a good approximation to the more rigorous time-dependent Markov models.     

Intermediate-term outcome of cervical spinal cord-injured patients older than 50 years of age

STUDY DESIGN: This study retrospectively reviewed the intermediate-term clinical outcome of patients who were 50 years of age or older at the time they experienced their cervical spinal cord injury. OBJECTIVES: To establish reasonable expectations for the functional outcome in the older patient with cervical spinal cord injury. BACKGROUND DATA: The long-term morbidity and mortality of large groups of patients with spinal cord injury have been reported. The specific functional ability, disposition, morbidity, and mortality of this group of older patients injured after 50 years of age, however, have been less well defined. METHODS: Forty-one consecutive patients older than 50 years of age at the time of cervical cord injury were studied, and functional abilities, independence, need for assistance in activities of daily living, disposition, morbidity, and mortality were assessed. All patients had more than 2 years of follow-up examinations (mean, 5.5 years) by the same spine injury service. RESULTS: There were 13 complete and 28 incomplete cervical cord lesions. The mean age of the patients at follow-up examination was 67.5 years. The average follow-up period was 5.5 years after injury. None of the patients with complete cord injury improved, and all required extensive care. Twenty-one (80%) of 26 of the patients with incomplete cord injury were able to ambulate with some assistance. Nineteen of 26 patients had independent or near-independent abilities with activities of daily living. Twenty (77%) of 26 were able to return home. All patients with complete cord injury (13 of 13) had died by the time of the follow-up visit. Seventy-seven percent (10 of 13) of this patient group had died within the first year. Those surviving lived an average of 3.5 years after their injury. Fourteen of 28 patients with incomplete cord injury (50%) had died by the time of the follow-up visit. Six (43%) of the 14 deaths were attributed to complications of their spinal cord injury. CONCLUSION: The functional outcome of the person older than 50 years with a complete cervical cord injury is poor. Of the 14% who survived the first year, all required extensive attendant care, and no neurologic improvement was seen. The patient with an incomplete cord injury has an overall good outcome regarding ambulation and returning to home.     

Gestational choriocarcinoma metastatic to the brain treated successfully by stereotactic radiosurgery and chemotherapy

This report analyzes the intracorporal lengths of 236 consecutive organically impotent men who underwent insertion of a penile prosthesis. The average right or left intracorporal length in this series was 20.9 cm, with a standard deviation of 2.2 cm. Intracorporal length ranged from 14-27 cm. This data may be used as reference ranges for penile prosthesis manufacturers, and for Urologists who implant prostheses or perform penile lengthening procedures.     

Expression of topoisomerase II, bcl-2, and p53 in three human brain tumor cell lines and their possible relationship to intrinsic resistance to etoposide

We characterized three human brain tumor cell lines (D54, HBT-20, and HBT-28) with respect to resistance to etoposide (VP-16), a topoisomerase II-reactive drug. All three cell lines were inherently resistant to VP-16 when compared to other human cell lines, with D54 showing the greatest resistance using colony formation assays. Resistance to VP-16 has been attributed to decreased drug uptake and changes in topoisomerase II; however, drug uptake and topoisomerase II protein levels (immunoblot) were no lower in D54 than in HBT-20 and HBT-28, cell lines relatively more sensitive to VP-16. More to the point, measurement of topoisomerase II-mediated DNA cleavage of cellular DNA after treatment with VP-16 showed that the topoisomerase II in these cells was active. These data indicate mechanisms other than those attributable to decreased drug uptake or altered topoisomerase II exist for clinical resistance to VP-16. VP-16-induced DNA cleavage has been associated with apoptosis in some cell lines; however, neither DNA laddering nor morphological changes characteristic of apoptosis were detected in these cell lines after treatment with VP-16. Bcl-2 and mutant p53 were present in these cells. Either of these conditions can prevent apoptosis and could explain a dissociation between the proximal mediator of VP-16-induced cytotoxicity (topoisomerase II-DNA complex formation) and cellular death.