beta(2)-adrenergic receptor Arg16/Arg16 genotype is associated with reduced lung function, but not with asthma, in the Hutterites.

In a genome-wide screen for asthma loci in the Hutterites, a marker locus on chromosome 5q23-31 showed evidence of linkage to asthma (C. Ober and colleagues, Hum. Molec. Genet. 1998;7:1393). To determine whether the beta(2)-adrenergic receptor (beta(2)AR) gene is the 5q-linked asthma locus in the Hutterites, we genotyped this sample for polymorphisms in the beta(2)AR gene. Neither the Arg16Gly nor Gln27Glu polymorphisms showed evidence of linkage to qualitative measures of asthma and bronchial hyperresponsiveness (BHR) (p > 0.10) or to quantitative measures of serum IgE and airway reactivity (p > 0.10). In contrast, FEV(1) percentage of predicted and FVC percentage of predicted were significantly lower among individuals homozygous for the Arg16 allele (FEV(1) %: 98.3 +/- 13.2% versus 103. 8 +/- 14.9%, p = 0.003; FVC %: 104.2 +/- 12.3% versus 108.3 +/- 13. 2%, p = 0.02 by t test). These findings held true for adolescents and adults, but not for children

Variation in the interleukin 4-receptor alpha gene confers susceptibility to asthma and atopy in ethnically diverse populations.

After a genomewide screen in the Hutterites was completed, the IL4RA gene was examined as the 16p-linked susceptibility locus for asthma and atopy. Seven known variants and one novel variant, representing all nonsynonymous substitutions in the mature protein, were examined in the Hutterites; on the basis of studies in the Hutterites, outbred white, black, and Hispanic families were genotyped for selected markers. All population samples showed evidence of association to atopy or to asthma (P values.039-.0044 for atopy and. 029-.0000061 for asthma), but the alleles or haplotypes showing the strongest evidence differed between the groups. Overall, these data suggest that the IL4RA gene is an atopy- and asthma-susceptibility locus but that variation outside the coding region of the gene influences susceptibility.

Induction of mutations by 2-acetylaminofluorene in lacI transgenic B6C3F1 mouse liver.

Mutations induced in liver cells by the hepatocarcinogen 2-acetylaminofluorene (2-AAF) were characterized after i.p. administration on 4 consecutive days at 100 mg/kg per injection in male B6C3F1 Big Blue transgenic mice that harbored the Escherichia coli lacI reporter gene. Animals were sacrificed at 5, 10 or 60 weeks following the last injection, livers removed and DNA packaged in vitro into bacteriophage lambda particles. The bacteriophage were assayed for lacI function by plating on E. coli in the presence of X-gal. Approximately 3 x 10(5) plaques were assayed per animal. Solvent-treated control mice exhibited a slight increase in mutant frequency over time, from 3.93 x 10(-5) at 5 weeks to 5.02 x 10(-5) at 60 weeks. In contrast, treatment with 2-AAF yielded an approximately 2-fold increase in mutant frequency at 5 and 10 weeks after treatment relative to controls, with frequencies of 8.13 x 10(-5) and 7.43 x 10(-5) respectively. However, by 60 weeks post-treatment the mutant frequency was not significantly increased over concurrent controls. Similar to results in other systems, 2-AAF induced predominantly single base changes targeted to G:C base pairs, primarily G:C-->T:A transversions (27%). In contrast to results in other bacterial and eukaryotic systems, no deletions were observed among the 2-AAF-induced mutations and the 4 base hot spot deletion that is frequently observed in lacI in E. coli was not observed in this system, suggesting that the lacI transgene may be relatively refractory to frameshift mutations in vivo in the mouse.

Assessment of the mutagenicity of dichloroacetic acid in lacI transgenic B6C3F1 mouse liver.

Dichloroacetic acid (DCA) is a chlorination byproduct found in finished drinking water. When administered in drinking water this chemical has been shown to produce hepatocellular adenomas and carcinomas in B6C3F1 mice over the animal's lifetime. In this study, we investigated whether mutant frequencies were increased in mouse liver using treatment protocols that yielded significant tumor induction. DCA was administered continuously at either 1.0 or 3.5 g/l in drinking water to male transgenic B6C3F1 mice harboring the bacterial lacI gene. Groups of five or six animals were killed at 4, 10 or 60 weeks and livers removed. At both 4 and 10 weeks of treatment, there was no significant difference in mutant frequency between the treated and control animals at either dose level. At 60 weeks, mice treated with 1.0 g/l DCA showed a 1.3-fold increase in mutant frequency over concurrent controls (P = 0.05). Mice treated with 3.5 g/l DCA for 60 weeks had a 2.3-fold increase in mutant frequency over the concurrent controls (P = 0.002). The mutation spectrum recovered from mice treated with 3.5 g/l DCA for 60 weeks contained G:C-->A:T transitions (32.79%) and G:C-->T:A transversions (21.31%). In contrast, G:C-->A:T transitions comprised 53.19% of the recovered mutants among control animals. Although only 19.15% of mutations among the controls were at T:A sites, 32.79% of the mutations from DCA-treated animals were at T:A sites. This is consistent with the previous observation that the proportion of mutations at T:A sites in codon 61 of the H-ras gene was increased in DCA-induced liver tumors in B6C3F1 mice. The present study demonstrates DCA-associated mutagenicity in the mouse liver under conditions in which DCA produces hepatic tumors.

Diagnostic accuracy of an international static-imaging telepathology consultation service.

Static-image and dynamic- (real-time) image telepathology are competing technologies. Although some studies suggest that the diagnostic accuracy of the dynamic-image telepathology approaches the accuracy of light microscopy, few reports have documented the diagnostic accuracy of static-image telepathology as used in the setting of an actual surgical pathology consultation practice. We report the results of an analysis of 171 telepathology consultation cases submitted to the Arizona-International Telemedicine Network (AITN). Digital images were submitted by pathologists from six participating institutions in Arizona, Mexico, and China. Telepathologists could render a telepathology diagnosis (TP) or defer rendering a diagnosis to obtain additional video images, glass slides for detailed analysis, or to obtain tissue blocks for special studies such as immunohistochemistry. The telepathologists rendered diagnoses for 144 cases and deferred 27 cases. Two pathologists retrospectively evaluated-glass slides from each case and rendered a consensus glass slide (GS) "truth" diagnosis. There was 88.2% concordance between TP and GS diagnoses (127 of 144 diagnoses). Concordance of 96.5% was achieved for clinically important diagnoses (139 of 144 diagnoses). Telepathologists deferred making a diagnosis to obtain glass slides for conventional light microscopy in 14 cases (8.1%) and for results of immunohistochemistry studies in 13 cases (7.6%). Thus, correct diagnoses were rendered by static-image telepathology in 127 of 171 cases (74.3%) at the time of telepathology diagnostic sessions. Inappropriate field selection and sampling biases of referring pathologists, as well as a tendency of static-image telepathologists to underestimate the complexity of some cases, may reduce the value of consultations based on the viewing of static images.

Cytogenetics of 158 patients with regional or disseminated melanoma. Subset analysis of near-diploid and simple karyotypes.

We report on the cytogenetic analyses of 158 cases of metastatic malignant melanoma, comprised of 63 cases with regional disease (RD) and 95 cases with distant (metastatic) disease (DD). Clonal structural abnormalities were identified in 126 (80%) cases and were significantly increased ( < 0.01 after adjusting for multiple comparisons) on chromosomes (in order of frequency of involvement) 1, 6, 7, 11, 9, and 3. Clustering of breakpoints occurred at 1p36, 1p22-q21, 6p11-q21, 9p, 11q23-qter, 13p (especially for cases with DD), and 19q13. The most common clonal numerical abnormalities, in a subset of 49 near-diploid cases were -10, -22, -9, +7, -19, and -Y. Analysis of chromosome segment gains and losses (CSRP) showed frequent loss of chromosomes 6 and 10, followed by equal rates of involvement of chromosomes 1, 7, and 9. Whole or segmental losses of chromosome 9 (especially 9p) correlate well with recent molecular genetic studies identifying putative suppressor genes, and are also likely important genetic abnormalities. However, based on the frequency of abnormalities in this large series of metastatic melanomas, it is likely that structural abnormalities of 1 and 6, and 10 are important in the pathogenesis of sporadic advanced melanoma.

Case triage model for the practice of telepathology.

OBJECTIVE: To implement and evaluate a practice model for telepathology. METHODS: A case triage practice model was devised in which general pathologists review all cases and refer them to subspecialists only when necessary. In 1993, the Arizona-International Telemedicine Network (AITN), a high-resolution static imaging telepathology diagnostic network, linking six sites to the University of Arizona in Tucson, began testing the model. Work flow through the network was analyzed, and diagnostic concordance was assessed in 150 surgical cases by comparing the diagnoses of the referring (transmitting) pathologists with diagnoses of the consulting (receiving) telepathologists as well as by comparing the referring pathologists' diagnoses with the consensus diagnoses reached by an independent review panel. Data analysis was controlled for subspecialty case type. Telepathologists had access to the referring pathologists' preliminary diagnoses, and the review panel had access to the original glass slides and the surgical pathology reports prior to rendering their respective diagnoses. RESULTS: The triage pathologist completed the telepathology consultation without the assistance of a subspecialty pathologist in 66% of the cases. The review panel examined the original glass slides from 134 cases by light microscopy. Concordance rates of the telepathologists' or review panel's diagnoses with the referring pathologists' diagnoses were not statistically different (93.1% v 83.6%, respectively; P > 0.05). CONCLUSION: The case triage model is suitable for the practice of telepathology. It significantly reduces the need for subspecialty pathologists. Static imaging telepathology is useful and reasonably efficient for rendering diagnostic opinions in the majority of referred cases. Tissue sampling limitations imposed by static imaging occasionally resulted in diagnostic errors.

Emphysema alters the deposition pattern of inhaled particles in hamsters.

How does pulmonary emphysema affect aerosol deposition? Groups of awake hamsters with emphysema (intratracheal elastase, 0.2 mg/100 g body wt) and age-matched controls (intratracheal saline) were exposed for 30 minutes to an insoluble radioactive aerosol (0.45 mu aerodynamic diameter) at 30, 60, or 90 days after instillation. Immediately after exposure, the animals were sacrificed. The lungs were excised, dried at total lung capacity, and sliced into 1-mm thick sections. Each slice was cut into pieces, which were counted for radioactivity and weighed. Then a measure of the uniformity of deposition, the evenness index (EI), was calculated. With perfect uniformity, all EIs would be one. We found fewer particles in the emphysematous, as compared with the control, lungs at 60 or 90 days after elastase instillation. The deposited particles were distributed less uniformly throughout the emphysematous lungs than in the control lungs. In controls, the standard deviation (SD) of the EI distribution (mean 1.0) averaged 0.33 for the three times studied. In elastase animals, the SD increased to 0.48 at 30 days, and at 60 days and 90 days the distributions were no longer normally distributed. This increased heterogeneity of deposition was also manifested as a loss of the normal apex-base gradient observed in control animals, an increase in the amount of nonventilated parenchyma, enhanced airway deposition, and an altered lobar deposition pattern. Morphometric analysis showed an increase in the mean linear intercept (MLI) of emphysematous lungs as compared with control lungs. However, the author found no correlation between MLI, a measure of emphysema, and EI, a measure of deposition, quantified in the same lung pieces. It is concluded that the emphysematous lesions produced by elastase markedly alter the deposition of an inhaled submicrometric aerosol. Factors that may contribute to these changes include airway obstruction and differences in breathing pattern in emphysematous as compared with control animals.

Computer-assisted correlation of structure and biological activity in a set of retinoids.

A computer-assisted pattern-recognition system (ADAPT) designed to elucidate structure-activity relationships was applied to a set of retinoids, potentially useful inhibitors of carcinogenesis. A data set of 67 retinoids was used as input to the ADAPT system; their structures were entered, and their 3-dimensional configurations were optimized by a molecular modelling algorithm. Forty of these retinoids were defined as the "more active" class based upon their ability to reverse keratinization in vitamin A-deficient hamster tracheal organ cultures at 10(-10) M or less. The remaining 27 retinoids were defined as the "less active" class due to their lack of ability to elicit this effect at 10(-8) M or more. Thirteen descriptors were generated by ADAPT for each of these retinoids based upon their structures, including: number of ring atoms; double bonds; del Ré sigma charges; and principal moments. Pattern recognition analysis techniques were applied to this data set to determine if information contained in these descriptors could generate a discriminant function equation which could separate more active from less active retinoids, successfully. Computer recognition of more active from less active retinoids was demonstrated by a number of pattern recognition techniques, and the discriminant function could predict correctly the relative activity of retinoids of "unknown" activity in 87% of trials. These results indicate the existence of distinct structure-activity relationships in this set of biologically important molecules.

Heterogeneity in responses of human and rodent respiratory epithelial cells to tumor promoters in culture.

Phorbol ester tumor promoters enhance the ability of primary normal rat tracheal epithelial cells to form colonies in a time-dependent fashion. The potency of phorbol derivatives in inducing this effect is relative to their potency as tumor promoters in mouse epidermis. Agents which do not interact with the putative TPA receptor are not effective. In contrast, both hamster tracheal and human bronchial epithelial cells are inhibited from forming colonies by phorbol esters. The sensitivity of human cells varied among individuals but could not be related to age, smoking history, or presence of a cancerous condition. These results bear some similarity to those of Harris et al. where levels of BP-DNA binding were measured in organ cultures of human bronchus. An interindividual variation of 120-fold was observed in 37 specimens of human bronchus, however, no correlation was apparent between levels of binding and whether the specimens were from patients with cancer. It would be of interest to determine if there is a relationship between carcinogen metabolism or binding and the ability to respond to promoters in specimens from normal and lung cancer patients. It is conceivable that lung cancer arises in individuals that have rare peculiarities in carcinogen metabolism combined with peculiarities in their responses to promoters present in cigarette smoke. Several conclusions can be drawn from these data. Species vary in response to tumor promoting agents, and the type of response may be a result of the biochemical events which are triggered by interaction with protein kinase C or another cellular receptor. Both responses, that of enhanced growth of epithelial cells observed in the rat, or that of inhibition of growth (induction of terminal differentiation) seen in human and hamster epithelial cells are consistent with proposed mechanisms by which tumor promoters may function. A general enhancement of cell proliferation may lead to fixation or expansion of genetic damage in initiated cells, while induction of terminal differentiation in normal cells could lead to expanded cell proliferation in initiated cells resistant to differentiation controls. This indicates that both responses may be useful in detecting environmental promoting agents. In light of these studies perhaps the hamster trachea may more closely mimic the responses of the human bronchus than does the rat. This is consistent with observations of the difficulty in transforming hamster tracheal epithelium (Dr. Brooke Mossman, personal communication) and human bronchial epithelium compared with rat tissue.(ABSTRACT TRUNCATED AT 400 WORDS)