The course of headache in idiopathic intracranial hypertension: a 12-month prospective follow-up study.

BACKGROUND AND PURPOSE: Our aim was to prospectively describe the course of headache during the first year of idiopathic intracranial hypertension (IIH). METHODS: Patients with newly diagnosed IIH were consecutively included from December 2010 to June 2013. Treatment according to standard guidelines was initiated. Headache history was obtained by headache diaries and standardized interviews performed at baseline and after 1, 2, 3 and 12 months. Parallel changes in papilledema were assessed by optical coherence tomography (OCT). All patients had comprehensive neuro-ophthalmological examinations including automated perimetry. RESULTS: Forty-four patients were included. Thirty-five patients completed the 12-month follow-up. Dramatic improvement in headache occurred within the first weeks after diagnosis. After 1 year, 15 patients reported no or only infrequent headache. However, 15 of the remaining 20 patients reported sustained chronic headache. Early age of onset and high diagnostic intracranial pressure (ICP) were associated with better headache outcome (≤1 headache days/month) after a year. Papilledema decreased rapidly within the first 2 months of diagnosis. After 1 year, OCT measures had normalized. Visual outcome was excellent in most patients. CONCLUSIONS: Although headache in 43% of patients responded well to ICP management, sustained long-term headache was seen in the remaining patients, despite resolution of papilledema. Headache in IIH may thus be attributed to more complex mechanisms than ICP elevation alone. High ICP and young age were associated with better headache outcome. Early treatment according to standard guidelines seems sufficient to ensure excellent visual outcome in the vast majority of patients.

First detection of TR46/Y121F/T289A and TR34/L98H alterations in Aspergillus fumigatus isolates from azole-naive patients in Denmark despite negative findings in the environment.

Azole-resistant Aspergillus fumigatus harboring the TR34/L98H or TR46/Y121F/T289A alterations is increasingly found in Europe and Asia. Here, we present the first clinical cases of TR46/Y121/T289A and three cases of TR34/L98H outside the cystic fibrosis (CF) population in Denmark and the results of environmental surveys. Four patients (2012 to 2014) with 11 A. fumigatus and 4 Rhizomucor pusillus isolates and 239 soil samples (spring 2010 and autumn 2013, respectively) with a total of 113 A. fumigatus isolates were examined. Aspergillus isolates were screened for azole resistance using azole-containing agar. Confirmatory susceptibility testing was done using the EUCAST microbroth dilution EDEF 9.1 reference method. For relevant A. fumigatus isolates, CYP51A sequencing and microsatellite genotyping were performed. Three patients harbored TR34/L98H isolates. Two were azole naive at the time of acquisition and two were coinfected with wild-type A. fumigatus or R. pusillus isolates, complicating and delaying diagnosis. The TR46/Y121F/T289A strain was isolated in 2014 from a lung transplant patient. Genotyping indicated that susceptible and resistant Aspergillus isolates were unrelated and that no transmission between patients occurred. Azole resistance was not detected in any of the 113 soil isolates. TR34/L98H and TR46/Y121F/T289A alterations appear to be emerging in the clinical setting in Denmark and now involve azole-naive patients. Two recent soil-sampling surveys in Denmark were unable to indicate any increased prevalence of azole-resistant A. fumigatus in the environment. These findings further support the demand for real-time susceptibility testing of all clinically relevant isolates and for studies investigating the seasonal variation and ecological niches for azole-resistant environmental A. fumigatus.

A prospective survey of Aspergillus spp. in respiratory tract samples: prevalence, clinical impact and antifungal susceptibility.

A three-month laboratory-based prospective survey was conducted at four major university hospitals covering one-third of the Danish population in order to determine the prevalence, significance, and susceptibility pattern of aspergilli in airway samples. Samples received in January-March 2007 for routine microbiologic investigation were examined for Aspergillus following routine procedures and with extended incubation (5 days). Identification was done by morphologic criteria and susceptibility testing using EUCAST method for azoles and amphotericin B E-test. Invasive aspergillosis (IA) was evaluated using modified EORTC/MSG criteria. A total of 11,368 airway samples were received. Growth of Aspergillus spp. was found in 129 and 151 patients using routine and extended incubation, respectively. Three patients had proven IA (2%), 11 probable (7%), four had allergic bronchopulmonary aspergillosis (ABPA) (3%), but the majority was colonised (88%). Underlying conditions were cystic fibrosis in 82 patients (55%), chronic obstructive pulmonary disease in 19 (13%) and haematological disorder in 11 (7%). Twenty-six patients (18%) were at intensive care unit and 69 (47%) received steroid treatment. Azole MICs were elevated for five isolates as follows (itraconazole, posaconazole, voriconazole MICs [mg/L]): two A. fumigatus isolates (>4; >4; 2 and >4; 0.125; 1), one A. lentulus isolate (2; 2; 0.5) and two A. terreus isolates (2; 2; 2 and 2; 0.125; 1). For four isolates the amphotericin B MIC was >1 µg/ml (3/112 A. fumigatus, 1/2 A. terreus). In conclusion, Aspergillus appears to be an important pathogen in Denmark. Elevated itraconazole MICs were detected in 4% of the isolates including a multi-azole resistant isolate.

Medication overuse as a cause of chronic headache in shunted hydrocephalus patients.

PURPOSE: To highlight the group of hydrocephalus patients known to have a long history of shunt revisions and refractory chronic headache. When a shunt in perfect working order has no effect on headache, other causes of headache should be investigated. In this paper, patients with medication overuse headache are identified and the positive effect of medication withdrawal are described. MATERIALS AND METHOD: Patients with hydrocephalus and shunt referred from the neurosurgical department to the Danish Headache Centre were identified. In all cases, over- and underdrainage was ruled out prior to referral. Six patients with medication overuse headache were documented and their charts were reviewed retrospectively with specific attention to: shunt revisions, inpatient and outpatient contacts, headache data and medication use before and after withdrawal of analgesic medication overuse. RESULTS: A marked reduction in shunt revisions and inpatient contacts in five out of six patients was found and a reduction in outpatient contacts in four out of six patients. Furthermore, an improvement in headache intensity was found in three out of six patients and a reduction in duration was found in two out of six patients. CONCLUSION: This study indicates that it is important to identify shunt patients with persistent chronic headache from causes other than shunt malfunction. By reducing their analgesic intake, it is possible to reduce headaches, the number of surgical interventions and hospital contacts. Hopefully this will raise awareness and lead to further research on the subject.

Characterization of the TSU-PR1 cell line by chromosome painting and flow cytometry.

TSU-PR1 was originally reported as a prostatic carcinoma cell line derived from a lymph node metastasis. Recently, however, this cell line was reported to be derived from T24 bladder carcinoma cells, and thus further definition of its origin is needed. Conventional cytogenetic study of TSU-PR1 showed aneuploidy, ranging from 65 to 86 chromosome with a modal number of 80, and with 10 marker chromosomes, thus conventional cytogenetics cannot be used to determine which chromosomes or regions of chromosomes are critical in cancer development and progression of this cell line. The present study was conducted to characterize genetic changes of the cell line using comparative genomic hybridization (CGH), fluorescence in situ hybridization (FISH), and flow cytometry. CGH results showed that green-to-red fluorescence ratios were within the range of 0.85-1.15, except for a few chromosomes, which reflected near tetraploidy in TSU-PR1. Flow cytometric analysis of TSU-PR1 revealed a DNA index of 3.46n, which is close to the 3.48n calculated from a modal number of 80. The copy numbers of chromosomes 4, 6, 7, 17, and 20 determined by the DNA index and the CGH analyses were 2.85 +/- 0.09, 3.22 +/- 0.77, 3.01 +/- 0.26, 4.05 +/- 0.44, and 4.99 +/- 0.48, respectively. These numbers are also in accordance with the chromosome copy numbers determined with FISH: 2.98 +/- 0.23, 2.91 +/- 0.44, 2.74 +/- 0.44, 3.93 +/- 0.38, and 5.05 +/- 0.78 for chromosomes 4, 6, 7, 17, and 20, respectively (P > 0.05).

DNA copy number alterations in HIV-positive and HIV-negative patients with diffuse large-cell lymphomas.

Individuals infected with HIV are at increased risk of developing aggressive non-Hodgkin's lymphoma with a worse prognosis than those similarly afflicted without HIV infection. The underlying genetic differences in tumor behavior between these two groups are not known. We explored the hypothesis that lymphomas from HIV-positive individuals have distinct somatic genetic changes that may provide clues to the genetic basis of disease progression and outcome. Genome-wide DNA copy number alterations (CNAs) in primary tumors from 14 HIV-positive and 11 HIV-negative patients with diffuse large B-cell lymphoma (DLCL) were quantified using comparative genomic hybridization (CGH). Tumors from HIV-positive patients displayed fewer regional DNA-CNAs than those from patients who did not have HIV. When CNAs were present, they occurred at lower frequency in HIV-positive patients. Gains at chromosomes 8q and Xp were the most frequent changes in the HIV-negative group, and gains on 2p and 12q were common in the combined HIV-positive and HIV-negative groups. No alteration was specific to AIDS-related DLCL. These data suggest that fewer somatic genomic changes are needed for progression to DLCL in HIV-immunocompromised hosts, and that other factors, such as reduced immune surveillance, may contribute to neoplastic progression.

Detection of genetic changes in anal intraepithelial neoplasia (AIN) of HIV-positive and HIV-negative men.

Compared with HIV-negative individuals, HIV-positive individuals have a higher prevalence of anogenital human papillomavirus (HPV) infection, as well as a higher incidence of HPV-associated anal cancer. Little is currently known of chromosomal changes occurring in anal intraepithelial neoplasia (AIN), the probable precursor to anal cancer. Genetic changes in AIN were characterized by comparative genomic hybridization (CGH) in a study of samples obtained from 19 HIV-positive and 11 HIV-negative men. The proportion with genetic changes significantly increased with the severity of the histopathologic grade with none diagnosed as (0%) AIN 1; 5 of 17 (29%) as AIN 2; and 5 of 9 (56%) AIN 3 showing genetic changes (p = .02). This correlation was also found in study subjects who had multiple biopsies with different grades of pathology concurrently or serially over time. The most common regional DNA copy number change was gain mapped to chromosome arm 3q (12% of AIN 2 and 33% of AIN 3). This alteration was previously reported to be commonest alteration in cervical cancer, which suggests a common molecular pathway for these two HPV-associated anogenital neoplasias.

Measurement of DNA copy number at microsatellite loci using quantitative PCR analysis.

This report describes the development and validation of quantitative microsatellite analysis (QuMA) for rapid measurement of relative DNA sequence copy number. In QuMA, the copy number of a test locus relative to a pooled reference is assessed using quantitative, real-time PCR amplification of loci carrying simple sequence repeats. Use of simple sequence repeats is advantageous because of the large numbers that are mapped precisely. In addition, all markers are informative because QuMA does not require that they be polymorphic. The utility of QuMA is demonstrated in assessment of the extent of deletions of chromosome 2 in leukemias arising in radiation-sensitive inbred SJL mice and in analysis of the association of increased copy number of the putative oncogene ZNF217 with reduced survival duration in ovarian cancer patients.

Genetic instability and hematologic disease risk in Werner syndrome patients and heterozygotes.

Werner syndrome (WRN) is an uncommon autosomal recessive disease in which progeroid features are associated with genetic instability and an elevated risk of neoplasia. We have used the glycophorin A (GPA) somatic cell mutation assay to analyze genetic instability in vivo in WRN patients and heterozygotes. GPA variant frequencies were determined for 11 WRN patients and for 10 heterozygous family members who collectively carry 10 different WRN mutations. Genetic instability as measured by GPA O/N allele loss variant frequency was significantly increased, and this increase was strongly age-dependent in WRN patients. GPA O/N allele loss variants were also significantly elevated in heterozygous family members, thus providing the first evidence for in vivo genetic instability in heterozygous carriers in an autosomal recessive genetic instability syndrome. Our results and comparable data on other human genetic instability syndromes allow an estimate of the level of genetic instability that increases the risk of human bone marrow dysfunction or neoplasia.

Genetic alterations in microdissected prostate cancer cells by comparative genomic hybridization.

Molecular genetic abnormalities were assessed on 23 cases of prostate adenocarcinoma by performing microdissection on archived tumor tissue sections followed by degenerate oligonucleotide primed PCR (DOP-PCR) on extracted DNA, providing sufficient product to carry out comparative genomic hybridization (CGH). The results of CGH show a significant regional DNA copy number alteration in 100% of the cases. Copy number gains were detected most frequently in chromosome 8q (91.3%), followed by chromosome X (43.5%), and chromosomes 20, 7, 4, and 3 (8.7%). DNA copy number losses occurred most frequently in chromosome 18 (34.8%), followed by chromosome 20 (21.7%), chromosomes 16 and 22 (17.4%) and chromosomes 12, 17, and 19 (8.7%). Since tissue microdissection and DOP-PCR yields product for analysis that represents DNA from pure tumor cells. CGH shows high sensitivity in detecting copy number alterations. This method indicates regions of the genome that are likely to be driven to amplification or deletion by the presence of oncogenes or tumor suppressor genes, respectively. The most common alteration detected was a regional gain in copy number in chromosome 8 near 8q21, indicating an oncogene in this region may be key to development of prostate adenocarcinoma. Prostate Cancer and Prostatic Diseases (2000) 3, 110-114

Whole genome amplification and molecular genetic analysis of DNA from paraffin-embedded prostate adenocarcinoma tumor tissue.

PURPOSE: Often tissues obtained from prostate adenocarcinoma tumors embedded in paraffin are heterogeneous in cell type and must be carefully microdissected to acquire tissue fragments that provide homogeneous aliquots of tumor clones. Such tissue fragments rarely contain sufficient DNA to perform genomic characterization needed as an early step in localizing relevant oncogenes or tumor suppressor genes. We report that PCR using a degenerate oligonucleotide primer (DOP-PCR) can be applied to DNA samples from microdissected paraffin-embedded prostate adenocarcinomas, and this provides sufficient product for fluorescent allelic imbalance measurements or comparative genomic hybridization (CGH). MATERIALS AND METHODS: Samples were selected to be representative of those routinely obtained during prostatectomies, based on typical tumor stages (T2 and T3) and Gleason grades (range 3 +3 to 4 +5). For DNA analysis without prior DOP-PCR, only large tumors were selected to be sectioned. More than 50 specimens were analyzed. Close comparison of data obtained from analysis of DOP-PCR with those from non-DOP DNA was obtained on a subset 8 samples. To compare the allelic balance of DOP-PCR amplified DNA with that measured for non-DOP DNA, we analyzed allelic ratios on DNA from 5 different tissue samples processed by both microdissection and conventional sectioning. RESULTS: Systematic comparison of allelic imbalance results shows close similarity between DOP-PCR amplified product and non-DOP DNA, indicating that PCR product is a valid representation of the tumor genome. In addition, the difference between allelic balance and imbalance is more distinctive when microdissection followed by DOP-PCR is performed. Performing CGH on products of DOP-PCR also shows distinctive regional copy number alterations in DNA from microdissected tumor tissue. CONCLUSION: Either of these procedures allows distinction between benign and malignant genomes, and also allows independent analysis of genomic alterations in different portions of tumors. They also may be applied clinically for genomic characterization of small foci that frequently appear in prostates of elderly men who are showing no obvious pathological symptoms of adenocarcinoma.

Allelic imbalance mapping of chromosome 16 shows two regions of common deletion in prostate adenocarcinoma.

Allelic imbalance (AI) has now been reported on the long arm of chromosome 16 in several cancers including breast, prostate, hepatocellular carcinoma, and Wilms tumor. Such nonrandom AI is commonly associated with the presence of a tumor suppressor gene (TSG) at or near the tested locus. Previous studies in our laboratory indicated that prostate cancer genomes frequently exhibit a region of allelic loss near the q terminus of chromosome 16. Here we report a detailed, PCR based, allelic imbalance study at ten polymorphic loci on 16q. The data indicate that there are two common regions of 16q AI in prostate cancer, one at 16q21-22 (50% of informative cases) and another at 16q24.2-qter (56% of informative cases). These are similar to regions of 16q previously shown to exhibit AI in breast cancer. Neither of these regions shows correlation of AI with the clinical parameters; Gleason grade, tumor stage, or metastases.

Biological dosimetry of radiation workers at the Sellafield nuclear facility.

The British Nuclear Fuels plc facility at Sellafield performs a range of nuclear-related activities. The site has been in operation since 1950 and has, in general, employed a stable work force, many of whom have accumulated relatively high occupational exposures to ionizing radiation. This paper compares the physical dosimetry with two biological end points for evaluating radiation exposure: fluorescence in situ hybridization with whole-chromosome painting probes to quantify stable chromosome aberrations (translocations and insertions), and glycophorin A (GPA) analysis of variant erythrocytes. For the cytogenetic analyses, 81 workers were evaluated in five dose categories, including 23 with minimal radiation exposure (< or = 50 mSv) and 58 with exposures ranging from 173 to 1108 mSv, all but 3 being > 500 mSv. In a univariate analysis, the mean stable chromosome aberration frequencies showed a significant increase with dose category (P = 0.032), and with cumulative dose when dose is treated as a continuous variable (P = 0.015). The slope of the dose response for stable aberrations is 0.79 +/- 0.22 aberrations per 100 cells per sievert (adjusted for smoking status), which is less than that observed among atomic bomb survivors, and suggests a dose and dose-rate effectiveness factor for chronic exposure of about 6. Analyses of the data for GPA N/O and N/N variants from 36 workers revealed no correlation with dose. Neither was there a correlation between the frequencies of N/O GPA variants and stable aberrations, although a weak negative association was observed between N/N variant frequency and stable aberrations (r = -0.38, P = 0.05). These results provide clear evidence for the accumulation of stable aberrations under conditions of chronic occupational exposure to ionizing radiation and show that stable chromosome aberrations are a more sensitive indicator for chronic radiation exposure than GPA variants. In comparison with human studies of brief exposure, chronic low-dose exposures appear substantially less effective for producing somatic effects as reflected by stable chromosome aberrations.

Cumulative genetic damage in hematopoietic stem cells in a patient with a 40-year exposure to alpha particles emitted by thorium dioxide.

Thorotrast, a colloidal suspension of the long-lived radionuclide, thorium-232, was widely used as a radiographic contrast medium for several decades. Due to the poor excretion of the sol, however, Thorotrast would deposit in the liver, bone marrow and other tissue, and patients would receive alpha-particle irradiation for life. To gauge the cumulative genetic damage to hematopoietic stem cells due to chronic exposure to alpha particles, we conducted a multi-end-point evaluation in a 72-year-old man who had been administered a 32-ml bolus of Thorotrast during cerebral angiography performed over 40 years ago in 1950. Peripheral T lymphocytes were cultured to quantify the frequencies and cellular distributions of asymmetrical and symmetrical types of chromosome aberrations in first-division metaphases and micronuclei in cytokinesis-arrested interphase II cells. Aberrations were scored using classical chromosome group analysis methods and chromosome painting techniques. Assays of glycophorin-A (GPA) mutations in red blood cells were also performed to obtain a relative measurement of damage sustained by the erythroid stem cell population. Results revealed that approximately 30% of the lymphocytes in this patient contained one or more chromosome aberrations, the majority of which were of the "stable" type. About one-third of the lymphocytes with chromosome damage carried multiple aberrations, suggesting that significant numbers of stem cells survive exposures to alpha-particle radiation that induce complex genomic alterations. Increased frequencies of GPA mutations were observed, demonstrating that genomic damage is also induced in erythroid progenitors. The numbers of micronuclei in lymphocytes were only moderately increased compared to expected values for persons of comparable age, and thus this end point was not useful for quantifying exposure level. Despite the relatively severe burden of somatic cell damage induced by 40 years of internal alpha-particle irradiation, the patient remains surprisingly free of any serious illness.

Glycophorin A as a biological dosimeter for radiation dose to the bone marrow from iodine-131.

The frequency of peripheral blood erythrocyte variants exhibiting allelic loss of glycophorin A (N/M antigen) has been used previously as a biological dosimeter to assess somatic mutations in bone marrow cells from external whole-body irradiation. The aim of the present study was to determine whether this marker could be used as a measure of bone marrow genotoxicity induced by 131I in the treatment of thyroid cancer. Flow cytometry of immunolabeled erythrocytes was performed to enumerate glycophorin A variants before and after eight therapy doses of 131I administered to five patients with differentiated thyroid carcinoma. Bone marrow radiation exposure from each dose was calculated from the integrated retention of 131I in the whole body and in the blood. In addition, the accumulated dose to the bone marrow received from earlier 131I therapy was calculated for each patient. Regression analysis was performed on the frequency of two glycophorin A variant cell types (N/O and N/N) as a function of accumulated dose to the bone marrow. Frequency of N/O variant cells showed a significant dose-related increase with a slope of 10.9 x 10(-6) per sievert. This dose effect is about one-half that previously observed after whole-body external irradiation at high dose rate. This decreased response could be explained by the low dose rate of the radiation to the bone marrow from 131I.

'Spontaneous' genetic damage in man: evaluation of interindividual variability, relationship among markers of damage, and influence of nutritional status.

The 'spontaneous' frequency of genetic damage (normal background) and the possible relationship of this damage to nutritional variables in humans were investigated in 22 subjects using several indices of genetic damage. The subjects were chosen, out of 122 initially analyzed, for being at the extremes of the highest and lowest values of one index of genetic damage, the frequency of micronucleated erythrocytes in peripheral blood. This index reflects chromosomal damage and loss in bone marrow erythropoietic cells. The assay for micronuclei is convenient but is restricted to splenectomized individuals because the human spleen removes micronucleated cells. The initial 122 subjects were splenectomized, but all were normal and healthy at the time of this study and none had a previous history of neoplastic disease. Factors investigated were stability of micronucleus frequency as a function of time, correlations among multiple markers of genetic damage, and influence on damage indices of nutritional variables, including blood levels of folate, B12 and antioxidant vitamins. Among different individuals, the range of values was 10-fold or more in the erythrocyte micronucleus, glycophorin A, plasma ascorbate and urinary 8-hydroxydeoxyguanosine (oxo8dG) assays, was approximately 6-fold in the lymphocyte micronucleus assay, and was 2-fold in the lymphocyte sister chromatid exchange (SCE) assay. Red blood cell folate and plasma folate, B12 and alpha-tocopherol values varied by up to 10-fold among individuals. Micronucleus frequencies in erythrocytes and peripheral blood lymphocytes ranged from < 0.3 to 16.9/1000 in mature red blood cells, < 1 to 33/1000 in reticulocytes, and 2.5 to 15/1000 in binucleate lymphocytes. Frequencies of glycophorin A variant erythrocytes ranged from 5.6 to 77.3 x 10(6) N/0 cells and 3.2 to 16.2 x 10(6) N/N cells, and oxo8dG excretion varied from 32 to 397 pmol/kg/day. Although a wide range of values was observed in each genetic endpoint, the extreme values for various endpoints of genetic damage were not observed in the same individuals. The frequency of micronucleated erythrocytes varied over time within individuals and indicated that individuals with the highest levels of damage exhibit greater variability than those with lower levels. In some subjects, frequencies of micronucleated erythrocytes changed dramatically over an interval of 2-3 years: four subjects with initial micronucleated reticulocyte frequencies of 20.4, 5.9, 6.4 and 33/1000 changed to 2.5, 20.5, 18.5 and 12/1000, respectively. Among more than 150 individuals we have studied, including the 64 individuals studied by Everson et al. [(1988) J. Natl. Cancer Inst., 80, 525-529] and Smith et al. [(1990) Cancer Res., 50, 5049-5054], the seven individuals with the highest observed frequencies of micronucleated erythrocytes all had exceptionally low values of plasma folate, red cell folate, or plasma B12, suggesting that folate and B12 status are the major determinants of the types of damage that lead to spontaneous micronucleus formation in erythrocytic cells.

Biodosimetry of Chernobyl cleanup workers from Estonia and Latvia using the glycophorin A in vivo somatic cell mutation assay.

The reactor accident at Chernobyl in 1986 necessitated a massive environmental cleanup that involved over 600,000 workers from all 15 Republics of the former Soviet Union. To determine whether the whole-body radiation received by workers in the course of these decontamination activities resulted in a detectable biological response, over 1,500 blood samples were obtained from cleanup workers sent from two Baltic countries, Estonia and Latvia. Here we report the results of studies of biodosimetry using the glycophorin A (GPA) locus in vivo somatic cell mutation assay applied to 734 blood samples from these workers, to 51 control samples from unexposed Baltic populations and to 94 samples from historical U.S. controls. The data reveal inconsistent evidence that the protracted radiation exposures received by these workers resulted in a significant dose-associated increase in GPA locus mutations compared with the controls. Taken together, these data suggest that the average radiation exposure to these workers does not greatly exceed 10 cGy, the minimum levels at which radiation effects might be detectable by the assay. Although the protracted nature of the exposure may have reduced the efficiency of induction of GPA locus mutations, it is likely that the estimated physical doses for these cleanup worker populations (median reported dose 9.5 cGy) were too low to result in radiation damage to erythroid stem cells that can be detected reliably by this method.

Glycophorin A somatic cell mutation frequencies in Finnish reinforced plastics workers exposed to styrene.

We have used the glycophorin A (GPA) in vivo somatic cell mutation assay to assess the genotoxic potential of styrene exposure in 47 reinforced plastics workers occupationally exposed to styrene and 47 unexposed controls matched for age, gender, and active smoking status. GPA variant erythrocyte frequencies (Vf), reflecting GPA allele loss (phi/N) and allele loss and duplication (N/N) somatic mutations arising in vivo in the erythroid progenitor cells of individuals of GPA M/N heterozygous genotype, were flow cytometrically determined in peripheral blood samples from these subjects. Measurements of styrene exposure of the workers at the time of blood sampling showed a mean 8-h time-weighted average (TWA8-h) styrene concentration of 155 mg/m3 (37 ppm) in the breathing zone. Mean urinary concentrations of the styrene metabolites mandelic acid (MA) and mandelic acid plus phenyl glyoxylic acid (MA+PGA) were 4.4 mmol/liter (after workshift) and 2.1 mmol/liter (next morning), respectively. Multivariate analysis of covariance on log-transformed GPA Vf data with models allowing adjustment for age, gender, smoking status, and styrene exposure showed that N/N Vf were nearly significantly increased among all of the exposed workers (adjusted geometric mean, 6.3 per million versus 5.0 in the controls; P = 0.058) and were statistically significantly elevated (adjusted geometric mean, 6.8 versus 5.0 in the controls; P = 0.036) among workers classified into a high-exposure group according to personal TWA8-h concentration of styrene in the breathing zone of > or = 85 mg/m3 (20 ppm; Finnish threshold limit value). Women in this high exposure group showed especially elevated N/N Vf (adjusted geometric mean 8.5 versus 5.3 in control women; P = 0.020); this elevation was also significant if urinary MA+PGA of > or = 1.2 mmol/liter was used as the basis of classification (adjusted geometric mean, 8.3; P = 0.030). The occupational exposure could not be shown to influence phi/N Vf. Cigarette smoking was associated with significantly elevated GPA Vf among active smokers (P = 0.042 for phi/N and P = 0.020 for N/N) and among active and ex-smokers combined (P = 0.014 for N/N). Its influence on phi/N Vf was especially clear among active smokers in the control group (P = 0.005). An effect of smoking, nearly statistically significant, was also observed for the phi/N Vf of control ex-smokers (P = 0.055) and of all active and ex-smokers combined (P = 0.050). Thus, the two characterized chemical exposures experienced by this group of workers and controls appear to produce differential effects on the two independent classes of GPA variants enumerated in the assay. This result suggests that the genotoxicity of these agents is mediated, at least in part, by different genetic mechanisms. Styrene exposure is associated with a specific increase in GPA N/N Vf; these allele loss and duplication variants reflect predominantly somatic recombination mechanisms in erythroid progenitor cells. Tobacco smoke exposure in active and ex-smokers is also associated not only with an increase in N/N Vf but also with an increase in phi/N Vf, reflecting the induction of GPA gene-inactivating mutations, including point mutations and deletions. This finding is consistent with a broad mechanistic spectrum of tobacco smoke genotoxicity associated with this complex mixture of chemical mutagens. Finally, there was no detectable effect of age on phi/N Vf; however, a highly significant (P = 0.0002) increase in N/N Vf with age, even after adjustment for other variables, was observed.

Genetic alterations in untreated metastases and androgen-independent prostate cancer detected by comparative genomic hybridization and allelotyping.

A newly developed method of comparative genomic hybridization (CGH) employing quantitative statistical comparisons was applied to DNA from two different types of advanced prostate cancer tissue. Multiple CGH analyses were obtained for each chromosome in each tumor, and the results of point-by-point comparison of the mean tumor:normal color ratio to a control normal:normal color ratio in each of 1247 evenly distributed data channels constituting the entire human genome were interpreted as loss, gain, or no change in copy number in the tumor genome. Group I tissue was obtained from prostate cancer metastases from 20 patients, 19 of whom had received no prior prostate cancer treatment. This DNA also was analyzed by Southern and microsatellite allelotyping at 53 different loci on 20 different chromosome arms. CGH results agreed with allelotyping results at 92% of the informative loci studied. These samples, which contained highly enriched tumor DNA, showed the highest rates of alteration yet reported in several chromosomal regions known to be altered frequently in prostate cancer: 8q gain (85%), 8p loss (80%), 13q loss (75%), 16q loss (55%), 17p loss (50%), and 10q loss (50%). Group II tissue was obtained predominately from primary or recurrent tumor from 11 patients who had been treated with long-term androgen-deprivation therapy and developed androgen-independent metastatic disease. Quantitative CGH analysis on DNA from these tissues showed chromosomal alterations that were very similar to those found in group I, suggesting that untreated metastatic tumors contain the bulk of chromosomal alterations necessary for recurrence to occur during androgen deprivation. In the entire data set, a number of previously undetected regions of frequent loss or gain were identified, including losses of chromosomes 2q (42%), 5q (39%), 6q (39%), and 15q (39%) and gains of chromosomes 11p (52%), 1q (52%), 3q (52%), and 2p (45%). Chi-squared analysis showed a significantly higher frequency of gain of the 4q25-q28 region in tumors from African-American patients, indicating a possible oncogene whose activation may play a role in the higher rate of progression seen in this ethnic group. Additional study of these frequently altered regions may provide insight into the mechanism of prostate cancer progression and lead to important tools for tumor-specific prognosis and therapy.

Molecular characterization of glycophorin A transcripts in human erythroid cells using RT-PCR, allele-specific restriction, and sequencing.

Glycophorin A (GPA) is an erythroid-lineage-specific membrane sialoglycoprotein which occurs in two allelic forms, M and N, which form the antigens of the MN blood group. Purified cDNAs and RNAs isolated from peripheral blood and erythroleukemia cell lines, HEL and K562, were used to develop an RT-PCR technique for amplifying GPA gene transcripts (GYPA). The relative expression of transcripts from the M and N alleles was determined using restriction analysis of these amplified products with four allele-specific restriction endonucleases. The use of this method permits the sensitive identification of GYPA transcripts in these cells and confirms GPA protein expression in the erythroleukemia cell lines and the MN phenotypes of individuals determined by immunolabeling with GPA allele-specific monoclonal antibodies. A novel restriction pattern was obtained using peripheral blood RNA from two individuals with a rare inherited variant allele, GPA Mg. Sequencing of the cDNA obtained using this method revealed a single C to A transversion in the fourth codon in the mature GYPA N coding sequence is responsible for the difference between GYPA Mg and GYPA N.