A simple method for measuring plasma power in rf-GDOES instruments.

A method for determining plasma power in rf-GDOES is presented. It is based on an effective resistance located in the inductive coil of the impedance matching. The amount of electrical power consumed in the matching system depends on the capacitive current flowing through the matching system, which depends on the applied voltage, the stray capacity, and the frequency. This correction method is experimentally evaluated and compared with the integral plasma power calculation.

Task demands affect manual asymmetries in pegboard performance.

Previous work by Bryden and Roy (1999) showed a larger performance difference between the hands for placing pegs into holes on the Grooved Pegboard test than for removing pegs from the holes. The authors argued that these data provided evidence of the importance of task demands in manual asymmetries. However the study failed to control for the differing starting positions of the pegs. To clarify this possible confound, the purpose of the current investigation was to determine the influence of starting position on the between-hand performance differences on the Grooved Pegboard Test. To do so, both the start and end positions were manipulated, such that participants moved the pegs from the receptacle to another receptacle or to a set of holes, or participants moved the pegs from a set of holes to a receptacle or another set of holes. A total of 30 right-handed individuals (as classified using the Waterloo Handedness Questionnaire) participated in the experiment, completing five trials with each hand for each of the four conditions. While no significant effects of start position were found, a significant interaction between hand and end position, F(1.29) = 30.85, P<.001, was found for the time to complete the task, where larger differences between the hands, fovouring the right hand, were seen for placing pegs into the holes as opposed to the receptacles. This effect was also found when the data were expressed using a laterality quotient. The results are discussed in terms of the influence of task complexity on manual asymmetries.

A comparison of immunohistochemical stain quality in conventional and rapid microwave processed tissues.

Same-day turnaround of pathology specimens is desirable in this era of managed care, and rapid microwave tissue processing produces histologic features of a quality equivalent to overnight processing. We studied whether microwave-assisted rapid tissue processing adversely affects the quality of immunohistochemical staining. We selected 30 specimens (20 neoplastic and 10 nonneoplastic) from our routine surgical pathology workload. Paired large tissue blocks were made from each specimen type, one for microwave-assisted rapid processing and one for conventional processing. Two microarrays of 60 punches each were made from the donor blocks. The microarray blocks were examined for intensity and extent of staining by 44 commonly used antibodies. Slides were reviewed independently by 2 pathologists blinded to the type of processing used. In 5,280 tissue punches examined, we found a high degree of concordance in quality, as measured by intensity and extent of immunohistochemical staining, between microwave and routinely processed tissues. Our study demonstrates that quality of immunohistochemical staining is similar between rapid microwave and conventional processing. The potential need for immunohistochemical analysis is not a contraindication for microwave-assisted rapid tissue processing.

Global hypomethylation is common in prostate cancer cells: a quantitative predictor for clinical outcome?

This study was designed to determine if cytological detection of 5-methylcytosine (5MC) was feasible on prostate tumor sections and to determine if levels of 5MC differed in malignant compared to normal prostate tissue. We further sought to see if 5MC levels correlated with any clinical outcome data. Thirty prostate tumor sections were obtained from patients who underwent radical prostatectomies from 1988 to 1995; these represented a mix of low to high grade tumors. Clinical data were maintained for each of these patients with a minimum of 7 years of follow up. Sections were stained with a commercially available antibody to 5MC and immunocytochemistry levels were subsequently quantified using a computer-assisted true-color imaging system. Tumor and benign regions of the same archived sections were compared, in addition to a series of 12 normal prostate samples. Prostate cancer cells exhibited a pronounced global decrease in methylation compared with benign and normal tissue. This was observed in 29 of 30 patients (96.7%) studied and densitometric scanning of methylation staining indicated that this value was quantifiable. Overall, higher methylation values were detected in men who had positive surgical margins and recurrent disease. These data suggest that loss of methylation is a feature of prostate cancer, and partial gain of methylation (presumably at promoters of specific genes) is associated with clinical outcome and is measurable using whole-cell assays.

Resorption rate and biocompatibility characteristics of two polyester ventilation tubes in a guinea pig model.

OBJECTIVES: Determine the resorption rate and biocompatibility characteristics of 2 polyester ventilation tubes, and to determine whether soap and water exposure accelerates polyester tube degradation. STUDY DESIGN AND SETTING: 50/50 poly (D, L-lactide-co-glycolide; PLGA-50) and poly (L-lactide; PLA) polymers were placed into the tympanic membranes of Hartley pigmented guinea pigs. Integrity of the tubes was determined by weekly otoscopic examination. Biocompatibility was assessed by comparing auditory brainstem response (ABR) thresholds and by examining tympanic membrane changes following tube resorption. Shah minigrommet ventilation tubes were used as controls. In the second portion of this study, implanted PLGA-50 and PLA tubes were exposed weekly to a mixture of soap and water (1:5) until complete resorption was observed. Biocompatibility was assessed by periodic ABR testing and tympanic membrane examination. RESULTS: The PLA tubes remained in the tympanic membrane for a longer period (63.2 +/- 19.3 days) than the PLGA-50 (18.8 +/- 8.1 days). The tympanic membrane and resorbable tube interface demonstrated equivalent findings for auditory thresholds and tissue histopathology at the implant site compared to nonresorbable controls. The resorption behavior was not altered by exposure to soap and water. Tympanic membranes of all animals following tube degradation and soap water exposure were intact with minimal scarring and no signs of persistent foreign body response. The histological analysis showed that implantation of resorbable tubes was not accompanied by secondary infection with otorrhea through the tube, did not result in a permanent perforation or dislocation of the tube into the middle ear cavity, and was not followed by excess tympanosclerosis or localized or diffuse membrane atrophy. CONCLUSIONS AND SIGNIFICANCE: Resorbable polyester pressure equalization tubes demonstrate predictable resorption behavior and similar biocompatibility characteristics when compared with nonresorbable Shah minigrommet ventilation tubes. Exposure to soap water does not accelerate polyester tube degradation nor change the host tissue response during the indwelling period or after complete resorption. The data suggests that resorbable ventilation tubes are substantially equivalent to other FDA-approved tympanostomy devices with regard to safety and biocompatibility in the guinea pig model examined and may provide improved clinical performance by combining this approach with sustained release technology. EBM RATING: B-2.

Multiple abnormalities detected by dye reversal genomic microarrays in prostate cancer: a much greater sensitivity than conventional cytogenetics.

Prostate cancer remains the most common male malignancy in Western countries, yet limited information exists regarding genetic changes and clinical correlations. The advent of comparative genomic hybridization microarray (GM) technology has recently allowed for precise screening of DNAs for genetic copy number changes; this offers an advantage over previous techniques, including conventional cytogenetics. A problem with cytogenetic prostate cancer analysis has been the study of the appropriate cell types because this is a highly heterogeneous tumor. We have performed GM using the Spectral Genomics Inc. dye reversal platform on 20 primary prostate tumors. These tumor samples were from frozen tissue collected over the last 10 years and multiple clinical parameters, including follow-up were collected on these patients; cytogenetic analysis was previously attempted on all patients. Eighty percent (16/20) of specimens showed copy number changes, 65% of which were losses and 35% were gains of genetic material. The most common changes observed were loss of an interstitial region of 2q (8 cases, 40%), followed by loss of interstitial 6q (6 cases, 30%), loss at 8p and 13q (5 cases each, 25%), gain at 3p and loss at 5q, 16q, and Xq (4 cases each, 20%), and gain at 8p (3 cases, 15%). There was evidence of correlation of loss at 5q with a positive node status. Cytogenetic studies on these same patients only detected clonal changes in 40% (8/20) specimens and did not detect the majority of abnormalities seen by the GM technique. We propose this technology for the evaluation of prostate and other heterogeneous cancers as a rapid and efficient way to detect genetic copy number changes.

Adenocarcinoma arising in association with gastric heterotopic pancreas: A case report and review of the literature.

We report a case of adenocarcinoma arising in a focus of heterotopic pancreas, occurring in the stomach of a 52-year-old man. The patient presented with gastric outlet obstruction. Radiographic studies revealed thickening of the gastric wall, but endoscopy failed to reveal a mucosal abnormality. A 50% distal gastrectomy was performed, along with vagotomy. Microscopic examination revealed extensive involvement of the muscularis propria of the distal stomach by heterotopic pancreas. The ectopic pancreas had a microscopic appearance consistent with Heinrich's class III, in which the majority of the heterotopic pancreas was characterized by cystically dilated duct structures. Occasional islets were present. Intimately associated with the cystically dilated ducts was a prominent number of small infiltrating ducts lined by columnar or cuboidal cells with enlarged hyperchromatic nuclei containing prominent nucleoli. These were consistent with a well-differentiated invasive adenocarcinoma. Despite multiple sectioning, no connection between the adenocarcinoma and the overlying gastric mucosa was seen. Adenocarcinoma arising within ectopic pancreas is a rare occurrence with fewer than 30 well-documented cases reported in the world literature to our knowledge.

Human DNA topoisomerase I: An anticancer drug target present in human sarcomas.

New anticancer drugs targeting DNA topoisomerase I (topo I) are showing activity against human sarcomas. Laboratory studies have indicated that cells responsive to topo I-targeted drugs have elevated levels of topo I, require active DNA replication, and may require a functional apoptotic pathway. In this study, we evaluated these potential markers of topo I-targeted drug sensitivity in 55 cases of human sarcoma (42 high grade, 4 intermediate grade, and 9 low grade). By immunohistochemical staining, we observed elevated topo I expression in 20 of 55 neoplasms (36%). Immunohistochemical staining for the proliferation marker DNA topoisomerase II-alpha (topo II-alpha), showed that 15 of 55 neoplasms (27%) had topo II-alpha indices >50, indicating a large number of actively cycling tumor cells. Abnormal p53 expression was observed in 19 of the 55 cases (35%). None of the cases were interpreted as positive for ALK-1. To complement our immunohistochemical staining of topo I, we isolated functionally active topo I from extracts of a human sarcoma. These isolates demonstrated that sarcoma topo I is sensitive to topo I-targeted anticancer drugs. Of the 55 cases of human sarcoma, 7 (13%) had high levels of topo I, a large number of cycling tumor cells, and normal p53 expression. These are the molecular parameters that might suggest responsiveness to drugs targeting topo I.

A comparison of routine and rapid microwave tissue processing in a surgical pathology laboratory. Quality of histologic sections and advantages of microwave processing.

Rapid processing of histopathologic material is becoming increasingly desirable to fulfill the needs of clinicians treating acutely ill patients. Traditional techniques for rapid processing of paraffin-embedded tissues require 4 to 5 hours, delaying treatment for some critically ill patients and requiring additional shifts of technologists in the laboratory. Microwave processing further shortens this time, allowing even more rapid histopathologic diagnosis. Few data exist comparing quality of microwave-processed tissue with that processed by more traditional techniques. We randomly selected 158 paired specimens from 111 patients. One member of the pair was processed routinely overnight, while the other was processed by the rapid microwave technique. The slides then were compared for quality of histologic preparation in a blinded fashion by 2 pathologists. Eight routinely processed specimens were judged as suboptimal, while 6 microwave-processed specimens were judged as suboptimal and 1 was considered unsatisfactory for evaluation. In the remaining cases, the material obtained by the 2 techniques was considered of identical quality. Microwave processing considerably shortens the preparation time for permanent histologic sections without a demonstrable decrease in section quality or "readability."

Characterization of the D-xylulose 5-phosphate/D-fructose 6-phosphate phosphoketolase gene (xfp) from Bifidobacterium lactis.

A D-xylulose 5-phosphate/D-fructose 6-phosphate phosphoketolase (Xfp) from the probiotic Bifidobacterium lactis was purified to homogeneity. The specific activity of the purified enzyme with D-fructose 6-phosphate as a substrate is 4.28 Units per mg of enzyme. K(m) values for D-xylulose 5-phosphate and D-fructose 6-phosphate are 45 and 10 mM, respectively. The native enzyme has a molecular mass of 550,000 Da. The subunit size upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis (90,000 Da) corresponds with the size (92,529 Da) calculated from the amino acid sequence of the isolated gene (named xfp) encoding 825 amino acids. The xfp gene was identified on the chromosome of B. lactis with the help of degenerated nucleotide probes deduced from the common N-terminal amino acid sequence of both the native and denatured enzyme. Comparison of the deduced amino acid sequence of the cloned gene with sequences in public databases revealed high homologies with hypothetical proteins (26 to 55% identity) in 20 microbial genomes. The amino acid sequence derived from the xfp gene contains typical thiamine diphosphate (ThDP) binding sites reported for other ThDP-dependent enzymes. Two truncated putative genes, pta and guaA, were localized adjacent to xfp on the B. lactis chromosome coding for a phosphotransacetylase and a guanosine monophosphate synthetase homologous to products of genes in Mycobacterium tuberculosis. However, xfp is transcribed in B. lactis as a monocistronic operon. It is the first reported and sequenced gene of a phosphoketolase.

Hypermethylation of the caveolin-1 gene promoter in prostate cancer.

BACKGROUND: Hypermethylation of CpG islands in the promoter regions of tumor suppressor genes is one mechanism of tumorigenesis. Caveolin-1 (Cav-1), a gene coding for the structural component of cellular caveolae, is involved in cell signaling and has been proposed to be a tumor suppressor gene in several malignancies. This gene maps to 7q31.1, a site known to be deleted in some prostate tumors. We chose to examine the methylation status of the promoter region of Cav-1 to determine whether this gene could function as a tumor suppressor in prostate cancer METHODS: Genomic DNA from both tumor and normal prostate epithelial cells was obtained from paraffin-embedded prostate sections by laser capture microdissection (LCM). The methylation status of 24 CpG sites at the 5' promoter region of Cav-1 was analyzed by bisulfite-direct-sequencing after amplification by PCR using primers specific for bisulfate modified DNA. Immunohistochemistry staining with a cav-1-specific antibody was also performed to evaluate the expression of the gene RESULTS: Twenty of the 22 (90.9%) informative cases showed promoter hypermethylation in the tumor cell population when compared with adjacent normal prostate cells with an average Methylation Index (potential frequency of total possible methylated Cs) from tumor cells equal to 0.426 vs. 0.186 for normal cells (P = 0.001). While no association with Gleason grade was found, overall increased methylation correlated with PSA failure (P = 0.016), suggestive of clinical recurrence. Elevated immunoreactivity with a Cav-1 antibody was observed in tumor cells from 7 of 26 prostate samples tested; this was associated with a Gleason score but not correlated with PSA failure or Methylation Index CONCLUSIONS: CpG sites at the 5' promoter of Cav-1 are more methylated in tumor than in adjacent normal prostate cells. Hypermethylation of the Cav-1 promoter supports the notion that Cav-1 may function as a tumor suppressor gene in prostate cancer and evidence is presented suggesting that methylation status of this gene is not only a marker for cancer but also may be predictive of outcome.

A common deletion at chromosomal region 17q21 in sporadic prostate tumors distal to BRCA1.

Prostate cancer is the most common cancer in males in the United States, yet the etiology of this disease is still poorly understood. In previous work from our laboratory, one or more deleted regions were found in prostate tumors distal to the breast and ovarian cancer susceptibility gene (BRCA1) on chromosome 17. This suggested that genes at 17q21 may play a pivotal role in prostate cancer progression, and there may be new tumor suppressor genes at this locus. We now present a physical map built with P1, P1 artificial chromosome, and bacterial artificial chromosome clones encompassing a DNA sequence anchored by multiple STS markers. The analysis of prostate tumors indicated an 85-kb novel commonly deleted interval flanked by D17S1184-D17S183-D17S1203-D17S1860, which is at least 470 kb distal to the BRCA1 gene. Fifty-four of 126 prostrate cancer cases (43%) showed a deletion by a direct FISH technique using P1 probes in this region. Searching with clone end sequences in the sequence database BLAST, the deleted clone covered genomic DNA sequence that contained upstream binding factor (UBF), EPB3 genes, SHCL1, ASB-4-like sequence, and acidic protein-like sequence. PCR for the ESTs confirmed that these genes or ESTs are within the deletion region. Our results will be helpful for finding candidate tumor suppressor genes in prostate cancer.

Microdissection, DOP-PCR, and comparative genomic hybridization of paraffin-embedded familial prostate cancers.

There is a clear genetic component to prostate cancer susceptibility. Regions reported to be linked to prostate cancer include 1q24-25 (HPC-1), 1q42.2-43, and Xq27-28. There is limited genetic information on familial prostate tumors. We used the Utah Population Database to identify familial prostate cancer cases and selected 35 cases from high-risk families. Tissue blocks containing discernable tumor were available from 19 cases; 13 of these yielded adequate specimens for analysis. Six cases came from families with linkage to HPC-1, 3 were known to have linkage to Xq27-28, and 4 had no linkage to a known locus; 7 cases were analyzed from patients who showed no known linkage (sporadic tumors) as controls. These paraffin-embedded tumors were laser microdissected, degenerate oligonucleotide (DOP)-amplified, and labeled for fluorescence detection by comparative genomic hybridization (CGH). Loss of 7q, 10q, and 16q and gain of 8q were common abnormalities present in both familial and sporadic tumors. Distinctive abnormalities included loss of 3p12-3p22 in 3 of 6 HPC-7-linked cases and in 2 of 3 X-linked cases and gain of 6q11-6q21 in 2 each of HPC-1 and X-linked tumors. In conclusion, laser microdissection, DOP-PCR, and CGH is a feasible method for analysis of paraffin-embedded prostate tumors. This study provides preliminary data suggesting that familial prostate cancer harbors some unique genetic changes when compared with sporadic prostate tumors.

Subperiosteal ganglion of the distal radius: a case report.

We present an unusual case of a subperiosteal ganglion of the distal radius.

Chromosome 7 abnormalities in prostate cancer detected by dual-color fluorescence in situ hybridization.

Aneusomy of chromosome 7 and loss at 7q (especially 7q31.1) have been reported in prostate cancer. To further investigate abnormalities of 7q and the relationship with whole chromosome 7 changes, we have conducted a dual-color fluorescence in situ hybridization (FISH) analysis on isolated nuclei from 28 primary prostate cancers. A pericentromeric probe for chromosome 7, five newly isolated sequence-specific bacterial artificial chromosome (BAC) probes from 7q31.1, and one BAC for the epidermal growth factor receptor (EGFR) gene at 7p12 were used in dual color hybridizations. Pericentromeric probes for chromosomes X and 4 were also used as controls. Sixteen (57.1%) of the 28 tumors showed clonal aberrations. Nine of them were trisomy 7 and four were hypertetrasomy for chromosome 7. Deletions at 7q31.1 were found in two of the high grade tumors. With the exception of these two cases, all other cases showed concordant results using all probes. These findings confirm previous studies that aneusomy of 7 is associated with prostate cancer progression, and there may be a tumor suppressor gene (TSG) at 7q31.1 which is associated with tumor progression. In addition, our study indicates: (1) the deletion pattern of individual nuclei infers that deletions at 7q31.1 precede reduplications of chromosome 7; and (2) the amplification of EGFR was not detected at the DNA level, suggesting that activation of this oncogene may play a minor role in prostate cancer.

Commonly occurring loss and mutation of the MXI1 gene in prostate cancer.

One of the most common chromosomal abnormalities in prostate cancer involves loss of 10q22-qter. Rarely, a smaller deletion, involving 10q24-q25, has been observed, suggesting the presence of a tumor suppressor gene at this site. We previously demonstrated that the MXI1 gene maps to 10q24-q25 and is mutated in some tumors with cytogenetically detectable deletions of this locus. MXI1 encodes a basic-helix-loop-helix protein that suppresses the transcriptional activity of the MYC oncoprotein by competing for the common dimerization partner, MAX, and binding to identical DNA sites. Because more than 90% of prostate tumors contain no cytogenetic abnormality of 10q, the relevance of MXI1 loss and/or mutation to the vast majority of cases remains unclear. We prospectively evaluated prostate tumors for loss of MXI1 by fluorescence in situ hybridization (FISH) and cytogenetic techniques. Twenty-one of 40 tumors (53%) demonstrated loss of a single MXI1 allele as determined by FISH. Ten cases with cytogenetically normal 10qs, but with FISH-documented deletion of MXI1, were examined at the molecular level, and eight mutations were identified, albeit at low frequency. Five of the mutant proteins were unable to bind DNA in association with MAX. We conclude that MXI1 gene loss in prostate cancer is common and most frequently involves a cytogenetically undetectable deletion.

Allelic loss detected on chromosomes 8, 10, and 17 by fluorescence in situ hybridization using single-copy P1 probes on isolated nuclei from paraffin-embedded prostate tumors.

We have implemented a reliable new technique for preparing isolated prostate cancer nuclei from paraffin-embedded tissue sections followed by analysis with single-copy fluorescence in situ hybridization (FISH). Our initial validation is described by comparison of our data with fresh prostate tumor tissue and loss of heterozygosity (LOH) studies. We also describe evaluation of 36 previously unstudied prostate cancer patients. Fifteen archival samples were selected from patients who underwent radical prostatectomy in which direct FISH and LOH data were available. Isolated nuclei were prepared and allelic loss was detected on 17q using a single-copy DNA (P1 phage) probe by FISH. A high (80%) concordance was found when comparing isolated nuclei data with 17q results from fresh preparations and LOH studies. We also examined loss at sites on 8p, 10q, and 17q in samples from 36 patients for whom clinical information was available. Loss was found at any of the three loci in 32/36 (89%) of the specimens with specific loss in 53% of the cases at the 8p locus, 33% at the 10q locus, and 61% at the 17q locus. Studies indicate that, as well as providing potential clinical information, isolated nuclei preparations are as reliable as fresh tissue for single-copy FISH studies.

Renal cryoablation in a canine model.

OBJECTIVES: To assess the potential safety and utility of cryoablation for treatment of selected renal tumors in a canine model. METHODS: Ultrasound and direct physical measurements (depth and width) of five cryolesions were compared. Cryolesions were examined histologically in 6 animals, which were killed at 4 hours, 2 days, 1 week, 3 weeks, 6 weeks, and 12 weeks. Mortality/morbidity was assessed in 12 animals over a 1-month interval, where 6 animals received small (approximately 2 cm) cryolesions and 6 animals received large (one third to one half of kidney) cryolesions. Laparoscopic cryoablation was performed in 2 animals. RESULTS: A statistically significant association of physical and ultrasound dimensions was observed (correlation coefficient R = 0.9295; P = 0.0001). Histologic studies in animals killed up to 1 week after cryoablation revealed complete coagulative necrosis within the cryolesion. The boundary transition from normal to complete tissue necrosis occurred in 1 to 2 mm. Animals killed 3 weeks to 3 months after cryoablation revealed progressive organization with granulation tissue, chronic inflammation, hemosiderosis, fibrosis, and contraction of the cryolesion with parenchymal loss. Untreated renal tissue was histologically normal in all kidneys. No mortality or morbidity was detected in the 12 animals followed for 30 days regardless of the size of the cryolesion. Laparoscopic cryoablation was performed successfully in 2 animals without modification of standard laparoscopic methods. CONCLUSIONS: Sonographic, histologic, and laparoscopic data in a canine model suggest that cryoablation may be a safe, feasible, and useful method for treatment of selected renal neoplasms.