Atom-photon dressed states in a waveguide-QED system with multiple giant atoms

We study the properties of bound states in waveguide-QED systems consisting of multiple giant atoms coupled to a coupled-resonator waveguide. Based on the general analytical expressions for these states and the corresponding energy spectra, we analyze in detail the threshold conditions for the appearance of bound states and the photon-mediated interactions between dressed atoms for different configurations. In addition, when multiple giant atoms are coupled to the waveguide, different types of interacting atomic chain can be obtained by manipulating the coupling configurations. Accordingly, the energy spectra of the bound states form metaband structures in the photonic band gaps. This makes the system a useful platform for quantum simulation and quantum information processing.

[Growth rate of adult obesity prevalence in China and target population for prevention and control from 2013 to 2018]

Objective: To investigate the annual growth rate of obesity prevalence of residents aged 18 and above in China and prevention keypoints for target populations from 2013 to 2018. Methods: This was a cross-sectional study. Subjects from China Chronic Disease and Risk Factor Surveillance project in 2013 and 2018 were included. The prevalence of obesity and growth rate in 31 provinces (autonomous regions and municipalities) in China were collected through survey questionnaires and on-site measurements. Other demographic data such as the proportion of obesity control measures, diet, exercise and drug use was also analyzed. Obesity among adults was defined as body mass index≥28.0 kg/m². Results: A total of 174 736 residents, aged (51.5±14.2) years, which included 74 704 (42.8%) males were recruited in 2013, and 179 125 residents, aged (55.1±13.8) years, which included 79 337 (44.3%) males were included in 2018. The average annual increase rate of adult obesity prevalence in China from 2013 to 2018 was 3.2% (uncertainty interval (UI) 2.7%-3.6%), and the average increase rate of obesity prevalence among men (5.2% (UI 4.6%-5.9%)) was higher than that of women (0.9% (UI 0.5%-1.3%)). For subgroups analysis, the average increase rate of obesity prevalence among residents aged 18 to 29 (7.4% (UI 6.9%-7.9%)), education level beyond college degree (6.3% (UI 5.5%-7.1%)), and unmarried population (11.2% (UI 10.2%-12.1%)) were higher than that of other subgroups between 2013 and 2018. The residents in Hainan province showed the highest average annual growth rate of obesity. With the exception of Shanxi, Hunan, Gansu and Ningxia province, the annual growth rate of obesity prevalence among adults increased in all other provinces (autonomous regions and municipalities) from 2013 to 2018. For the obese population, the proportion of people who took weight control measures increased from 22.6% in 2013 to 32.7% in 2018. Conclusions: The prevalence of obesity growth characteristics in subpopulations and regions in China are obviously different. Accordingly the focus points of obesity prevention and control in different regions should have their own emphasis.

[Associations between glycated hemoglobin and glucose indicators in adults in areas at different altitude in China]

Objective: To explore the associations of glycated hemoglobin (HbA1c) with FPG and oral glucose tolerance test 2-hour (OGTT-2 h) in areas at different altitude in China. Methods: Subjects who participated in 2018-2019 China Chronic Disease and Risk Factor Surveillance and had no prior type 2 diabetes diagnosis were included. Subsequently, they were categorized into three groups based on altitude of living area (<2 000, 2 000- and ≥3 000 m). With adjustment for intracluster correlation, multivariable linear regression analysis was performed to evaluate the associations of HbA1c with FPG and OGTT-2 h in the context of HbA1c was normal (<5.7%) or abnormal (≥5.7%). Furthermore, the shape of relationships between HbA1c and glucose indicators was examined using restricted cubic spline. Finally, receiver operating characteristic curve was used to evaluate the diagnostic performance of HbA1c for diabetes. Results: A total of 157 277 subjects were included in the analysis. While FPG and OGTT-2 h levels gradually decreased with increase of altitude, HbA1c level was similar among the three groups. When HbA1c was <5.7%, its association with FPG and OGTT-2 h was weak and no obvious difference was observed among the three groups. When HbA1c was ≥5.7%, the FPG and OGTT-2 h increased by 15.45% (95%CI:14.71%- 16.18%) and 24.54% (95%CI:23.18%-25.91%) respectively per one standard deviation increase in HbA1c in group in area at altitude <2 000 m. However, the FPG and OGTT-2 h increased by 13.08% (95%CI:10.46%-15.76%) and 21.72% (95%CI:16.39%-27.31%), respectively, in group in area at altitude 2 000- m, and increased by 11.41% (95%CI:9.32%-13.53%) and 20.03% (95%CI:15.38%- 24.86%), respectively, in group of altitude ≥3 000 m. The restricted cubic spline indicated that the curve showing the association of HbA1c with FPG and OGTT-2 h was flat when HbA1c was <5.7%, but showed a positive linear relationship when HbA1c was ≥5.7%. The area under curve for detecting diabetes was 0.808 (95%CI:0.803-0.812) in group of altitude <2 000 m and 0.728 (95%CI:0.660-0.796, P=0.022) in group of altitude ≥3 000 m. The relevant optimal cutoff value of HbA1c was 5.7%, with a sensitivity of 65.4% and a specificity of 83.0%, and 6.0%, with a sensitivity of 48.3% and a specificity of 93.7%, respectively. Conclusions: When HbA1c was ≥5.7%, the association between HbA1c and glucose indicators became weaker as the increase of altitude. In the area at altitude ≥3 000 m, it may not be appropriate to use HbA1c in the diagnosis of diabetes.

Analysis of retinal arteriolar and venular parameters in primary open angle glaucoma

AIM

To measure the retinal vessels of primary open angle glaucoma (POAG) patients on spectral domain optical coherence tomography (SD-OCT) with a full-width at half-maximum (FWHM) algorithm to better explore their structural changes in the pathogenesis of POAG.

METHODS

In this retrospective case-control study, the right eyes of 32 patients with POAG and 30 healthy individuals were routinely selected. Images of the supratemporal and infratemporal retinal vessels in the B zones were obtained by SD-OCT, and the edges of the vessels were identified by the FWHM method. The internal and external diameters, wall thickness (WT), wall cross-sectional area (WCSA) and wall-to-lumen ratio (WLR) of the blood vessels were studied.

RESULTS

Compared with the healthy control group, the POAG group showed a significantly reduced retinal arteriolar outer diameter (RAOD), retinal arteriolar lumen diameter (RALD) and WSCA in the supratemporal (124.22±12.42 vs 138.32±10.73 µm, 96.09±11.09 vs 108.53±9.89 µm, and 4762.02±913.51 vs 5785.75±1148.28 µm², respectively, all P<0.05) and infratemporal regions (125.01±15.55 vs 141.57±10.77 µm, 96.27±13.29 vs 110.83±10.99 µm, and 4925.56±1302.88 vs 6087.78±1061.55 µm², all P<0.05). The arteriolar WT and WLR were not significantly different between the POAG and control groups, nor were the retinal venular outer diameter (RVOD), retinal venular lumen diameter (RVLD) or venular WT in the supratemporal or infratemporal region. There was a positive correlation between the arteriolar parameters and visual function.

CONCLUSION

In POAG, narrowing of the supratemporal and infratemporal arterioles and a significant reduction in the WSCA is observed, while the arteriolar WT and WLR do not change. Among the venular parameters, the external diameter, internal diameter, WT, WLR, and WSCA of the venules are not affected.

[Allelopathic effects of velvetleaf volatile oil on germination and seedling growth of wheat, maize, and soybean]

Velvetleaf (Abutilon theophrasti) is a common weed in dryland, which can reduce crop yield. Allelopathy is one of the possible reasons resulting in crop yield reduction. In this study, we analyzed the allelopathic effect of velvetleaf volatile oil components on germination and seedling growth of three dryland crops, wheat (Triticum aestivum), maize (Zea mays), and soybean (Glycine max). A total of 26 compounds in velvetleaf volatile oil were identified by GC-MS, accounting for 98.1% of the total chromatographic peak areas. The terpenes with lower molecular weight in the volatile oil were α-pinene, eucalyptol, α-terpinolene, β-terpinene, trans-α-ionone, and trans-β-ionone. The saturated aqueous solution of velvetleaf volatile oil could inhibit seed germination of three crops by filter paper and soil. Velvetleaf volatile oil could inhibit the seedling growth of three crops through air, filter paper, and soil. Wheat was the most susceptible to volatile oil, followed by maize and soybean. The inhibitory effect of volatile oil on the growth of wheat was the strongest in air medium, followed by filter paper and soil medium. The lower molecular weight of terpene components from volatile oil might be the important allelochemicals.

Site-Saturated Mutagenesis of Histidine 234 of Saccharomyces cerevisiae Oxidosqualene-Lanosterol Cyclase Demonstrates Dual Functions in Cyclization and Rearrangement Reactions

Site-saturated mutagenesis experiments were carried out on the His234 residue of Saccharomyces cerevisiae oxidosqualene-lanosterol cyclase (ERG7) to characterize its functional role in ERG7 activity and to determine its effect on the oxidosqualene cyclization/rearrangement reaction. Two novel intermediates, (13alphaH)-isomalabarica-14(26),17E,21-trien-3beta-ol and protosta-20,24-dien-3beta-ol, isolated from ERG7(H234X) mutants, provided direct mechanistic evidence for formation of the chair-boat 6-6-5 tricyclic Markovnikov cation and protosteryl cation that were assigned provisionally to the ERG7-catalyzed biosynthetic pathway. In addition, we obtained mutants that showed a complete change in product specificity from lanosterol formation to either protosta-12,24-dien-3beta-ol or parkeol production. Finally, the repeated observation of multiple abortive and/or alternative cyclization/arrangement products from various ERG7(H234X) mutants demonstrated the catalytic plasticity of the enzyme. Specifically, subtle changes in the active site affect both the stability of the cation-pi interaction and generate product diversity.

Tryptophan 232 within Oxidosqualene−Lanosterol Cyclase from Saccharomyces cerevisiae Influences Rearrangement and Deprotonation but Not Cyclization Reactions

[reaction: see text] Oxidosqualene-lanosterol cyclases convert oxidosqualene to lanosterol in yeast and mammals. Site-saturated mutants' construction of Saccharomyces cerevisiae oxidosqualene-lanosterol cyclase, at Trp232 exchanges against proteinogenic amino acids, and product profiles are shown. All mutants, except Lys and Arg, produced protosta-12,24-dien-3beta-ol, lanosterol, and parkeol. Overall, Trp232 plays a catalytic role in the influence of rearrangement process and determination of deprotonation position but does not involve intervention in the cyclization steps.

Common trisomy mosaicism diagnosed in amniocytes involving chromosomes 13, 18, 20 and 21: karyotype-phenotype correlations

Karyotype-phenotype correlations of common trisomy mosaicism prenatally diagnosed via amniocentesis was reviewed in 305 new cases from a collaboration of North American cytogenetic laboratories. Abnormal outcome was noted in 10/25 (40%) cases of 47,+13/46, 17/31 (54%) cases of 47,+18/46, 10/152 (6.5%) cases of 47,+20/46, and in 49/97 (50%) cases of 47,+21/46 mosaicism. Risk of abnormal outcome in pregnancies with less than 50% trisomic cells and greater than 50% trisomic cells were: 26% (4/15) versus 60% (6/10) for 47,+13/46, 52% (11/21) versus 75% (6/8) for 47,+18/46, 4.5% (6/132) versus 20% (4/20) 47,+20/46, and 45% (27/60) versus 59% (22/37) for 47,+21/46. Phenotypically normal liveborns were observed with mean trisomic cell lines of 9.3% for 47,+13/46, 8.6% for 47,+18/46, 27% for 47, +20/46, and 17% for 47,+21/46. Cytogenetic confirmation rates were 46% (6/13 cases) for 47,+13/46 mosaicism, 66% (8/12 cases) for 47, +18/46, 10% (10/97 cases) for 47,+20/46, and 44% (24/54 cases) for 47,+21/46. There were higher confirmation rates in pregnancies with abnormal versus normal outcome: 50% versus 44% for 47,+13/46 mosaicism, 100% versus 33% for 47,+18/46, 66% versus 7% for 47, +20/46, and 55% versus 40% for 47,+21/46. Repeat amniocentesis is not helpful in predicting clinical outcome. It may be considered when there is insufficient number of cells or cultures to establish a diagnosis. Fetal blood sampling may have a role in mosaic trisomy 13, 18, and 21 as the risk for abnormal outcome increases with positive confirmation: 1/5 (20%) normal cases versus 5/8 (62%) abnormal cases. High resolution ultrasound examination(s) is recommended for clinical correlation and to facilitate genetic counselling.

Wolf-Hirschhorn (4p deletion) syndrome: report of one case

Wolf-Hirschhorn syndrome is an uncommon chromosomal disorder caused by loss of material from the distal aspect of the short arm of chromosome 4. Its characteristic features include profound growth retardation with psychomotor delay, severe mental deficiency, facial dysmorphia, midline defects and skeletal anomalies. We herein report a case of 4p deletion syndrome and review related literature.

Human T-lymphocyte transformation with human T-cell lymphotropic virus type 2

Human T-cell lymphotrophic virus type 2 (HTLV-2), a common infection of intravenous drug users and subpopulations of Native Americans, is uncommon in the general population. In contrast with the closely related HTLV-1, which is associated with both leukemia and neurologic disorders, HTLV-2 lacks a strong etiologic association with disease. HTLV-2 does shares many properties with HTLV-1, including in vitro lymphocyte transformation capability. To better assess the ability of HTLV-2 to transform lymphocytes, a limiting dilution assay was used to generate clonal, transformed lymphocyte lines. As with HTLV-1, the transformation efficiency of HTLV-2 producer cells was proportionately related to the number of lethally irradiated input cells and was comparable to HTLV-1-mediated transformation efficiency. HTLV-2-infected cells were reproducibly isolated and had markedly increased growth potential compared to uninfected cells; HTLV-2 transformants required the continued presence of exogenous interleukin 2 for growth for several months and were maintained for over 2 years in culture. All HTLV-2-transformed populations were CD2 and/or CD3 positive and B1 negative and were either CD4+ or CD8+ populations or a mixture of CD4+ and CD8+ lymphocytes. Clonality of the HTLV-2 transformants was confirmed by Southern blot analysis of T-cell receptor beta chain rearrangement. Southern blot analysis revealed a range of integrated full-length genomes from one to multiple. In situ hybridization analysis of HTLV-2 integration revealed no obvious chromosomal integration pattern.

Rare trisomy mosaicism diagnosed in amniocytes, involving an autosome other than chromosomes 13, 18, 20, and 21: karyotype/phenotype correlations

In order to determine the significance of trisomy mosaicism of an autosome other than chromosomes 13, 18, 20, and 21, 151 such cases diagnosed prenatally through amniocentesis were reviewed. These rare trisomy mosaicism cases include 54 from 17 cytogenetic laboratories, 34 from a previous North American mosaicism survey, and 63 from published reports. All were cases of true mosaicism with information available on pregnancy outcome, and with no evidence of biased ascertainment. There were 11 cases of 46/47, +2; 2 of 46/47, +3; 2 of 46/47, +4; 5 of 46/47, +5; 3 of 46/47, +6; 8 of 46/47, +7; 14 of 46/47, +8; 25 of 46/47, +9; 2 of 46/47, +11; 23 of 46/47, +12; 5 of 46/47, +14; 11 of 46/47, +15; 21 of 46/47, +16; 7 of 46/47, +17; 1 of 46/47, +19; and 11 of 46/47, +22. As to the risk of an abnormal outcome, the data showed a very high risk (> 60 per cent) for 46/47, +2, 46/47, +16, and 46/47, +22; a high risk (40-59 per cent) for 46/47, +5, 46/47, +9, 46/47, +14, and 46/47, +15; a moderately high risk (20-39 per cent) for 46/47, +12; a moderate risk (up to 19 per cent) for 46/47, +7 and 46/47, +7 and 46/47, +8; a low risk for 46/47, +17; and an undetermined risk, due to lack of cases, for the remaining autosomal trisomy mosaics. Most cases were evaluated at birth or at termination, so subtle abnormalities may have escaped detection and developmental retardation was not evaluated at all. Comparison of the phenotypes of prenatally diagnosed abnormal cases and postnatally diagnosed cases with the same diagnosis showed considerable concordance. Since the majority of anomalies noted are prenatally detectable with ultrasound, an ultrasound examination should be performed in all prenatally diagnosed cases. In cytogenetic confirmation studies, the data showed much higher confirmation rates in cases with abnormal outcomes than in cases with normal outcomes [81 per cent vs. 55 per cent for fibroblasts (from skin, fetal tissue, and/or cord); 88 per cent vs. 46 per cent for placental cells; 22 per cent vs. 10 per cent for blood cells]. The confirmation rate reached 85 per cent when both fibroblasts and placental tissues were studied in the same case (with trisomic cells found in one or the other, or both). Therefore, one must emphasize that both fibroblasts and placental tissues should be studied. Except for 46/47, +8 and 46/47, +9, PUBS is of limited value for prenatal diagnosis of rate trisomy mosaicism. DNA studies for UPD are suggested for certain chromosomes with established imprinting effects, such as chromosomes 7, 11, 14, and 15, and perhaps for chromosomes 2 and 16, where imprinting effects are likely.

Identification and characterization of three genes and two pseudogenes on chromosome 13

A study was conducted on the feasibility of isolating genes and pseudogenes that map to chromosome 13 by a hybridization-based approach using a 13-specific library and pools of repeat-free cDNA clones. Five pairs of cDNA and chromosome 13 genomic clones were identified and characterized. Partial or full-length sequence was derived from all cDNAs, and database searches were performed for putative gene identification. Partial sequence was also obtained from the chromosome 13 genomic clones for comparison with those of the hybridizing cDNAs. As a result of these analyses we identified three genes, a putative homologue of a porcine mRNA encoding an unidentified hepatic protein, a putative homologue of a yeast integral membrane protein, and a gene for a translationally controlled tumor protein, and two processed pseudogenes, ribosomal proteins L23a and S3a. The latter was formerly identified as the v-fos transformation effector gene, Fte-1, and recently cited as a possible candidate for the BRCA2 gene on chromosome 13. All genes and pseudogenes were localized to cytogenetic bands by in situ hybridization of metaphase chromosomes with probes derived from the chromosome 13 genomic clones.

Incidence and significance of chromosome mosaicism involving an autosomal structural abnormality diagnosed prenatally through amniocentesis: a collaborative study

Among 179,663 prenatal diagnosis cases collected from ten institutions and two publications, 555 (0.3 per cent) were diagnosed as having chromosome mosaicism. Of these, 57 (10.3 per cent) were mosaic for an autosomal structural abnormality, 28 (5 per cent) for a sex chromosome structural abnormality, and 85 (15.3 per cent) were mosaic for a marker chromosome. Ninety-five cases of prenatally diagnosed mosaicism with a structural abnormality in an autosome and a normal cell line, and with a known phenotypic outcome, were collected for karyotype-phenotype correlations through our collaboration (40 cases), a prior survey (26 cases), and published reports (29 cases). They included 13 balanced reciprocal translocations, one unbalanced reciprocal translocation, four balanced Robertsonian translocations, four unbalanced Robertsonian translocations, four inversions, 17 deletions, three ring chromosomes, 19 i(20q), seven +i(12p), six other isochromosomes, and 17 partial trisomies resulting from a duplication or other rearrangement. All cases mosaic for a balanced structural rearrangement resulted in a normal phenotype. All cases of 46/46,i(20q) resulted in normal liveborns. Five of seven cases with 46/47,+i(12p) had an abnormal phenotype compatible with Killian-Pallister syndrome. The overall risk for an abnormal outcome for a mosaic case with an unbalanced structural abnormality, excluding 46/46,i(20q) and 46/47,+i(12p), is 40.4 per cent. In the same category, the study also suggested a correlation between the percentage of abnormal cells and an abnormal phenotype. For mosaicism involving a terminal deletion, the possibility of a familial fragile site should be considered.

Differential expression of alternatively spliced forms of MAP4: a repertoire of structurally different microtubule-binding domains

We previously reported that the microtubule (MT)-binding domain of microtubule-associated protein 4 (MAP4) contains three 18-amino acid imperfect repeats that are homologous to the repeats found in the MT-binding domains of the neuronal MAPs, MAP2 and tau [Chapin, S. J., & Bulinski, J. C. (1991) J. Cell Sci. 98, 27-36]. Here we report the isolation of clones encoding additional isoforms of MAP4, which differ in the number of repeated elements contained within their MT-binding domains. In addition to clones encoding three repeats, we isolated clones encoding a four-repeat isoform, whose MT-binding domain bears a striking similarity to the four-repeat isoform of tau. Other MAP4 clones that we isolated encode five repeats. The additional repeat in the five-repeat isoform of MAP4 is quite unusual in its amino acid sequence; this unusual repeat was also found by Aizawa et al. [Aizawa, H., et al. (1990) J. Biol. Chem. 265, 13849-13855] among the repeats encoded by bovine MAP4 clones possessing four repeats. In humans, MAP4 was recently shown to be encoded by a single-copy gene [West, R. R., et al. (1991) J. Biol. Chem. 266, 21886-21896]; we demonstrated that the human MAP4 gene is located on human chromosome 3p21. Expression of multiple MAP4 isoforms from this gene, which appears to result from alternative RNA splicing, was investigated by RNase protection analysis of mammalian cell lines and rat tissues. The five-repeat isoform was the only form detectable in most cell lines, and it was the most abundant isoform expressed in rat lung, liver, kidney, spleen, and testis. However, in rat brain, heart, and skeletal muscle, although the five-repeat isoform was expressed at all developmental stages examined, the tau-like four-repeat isoform was also expressed, and its expression increased during development. The three-repeat isoform was expressed in heart and, to a lesser extent, in brain, skeletal muscle, and lung. Our results demonstrate that several different MAP4 isoforms are expressed in the rat in different tissues and at various developmental stages. Furthermore, our data suggest that differential expression of MAP4 isoforms possessing distinct MT-binding domains may be involved in the changes in MT dynamics or function that are known to accompany differentiation.

Selection of cDNAs using chromosome-specific genomic clones: application to human chromosome 13

We have developed a general method for en masse isolation of cDNAs present in a normalized library by hybridization to arrayed chromosome-specific phage lambda clones; we have used this approach to initiate exon-mapping of human chromosome 13. An advantage of the simultaneous isolation of cDNA/lambda pairs is that it allows cytogenetic assignment of a bona fide genomic clone by in situ hybridization, which also verifies that the corresponding cDNA or a homologous expressed sequence resides on chromosome 13. This information is enriched by partial sequencing of a selected cDNA from both ends. The sequence of the 3' noncoding region provides an 'identifier' that is used to develop STSs, while the sequence from the 5' end, often corresponding to a coding region, is used for homology searches in databases that occasionally reveal gene functions.

Assembly of ordered contigs of cosmids selected with YACs of human chromosome 13

We have developed an efficient method for assembling ordered cosmid contigs aligned to mega-YACs and midi-YACs (average insert sizes of 1.0 and 0.35 Mb, respectively) and used this general method to initiate high-resolution physical mapping of human chromosome 13 (Chr 13). Chr 13-enriched midi-YAC (mYAC) and mega-YAC (MYAC) sublibraries were obtained from corresponding CEPH total human YAC libraries by selecting colonies with inter-Alu PCR probes derived from Chr 13 monochromosomal cell hybrid DNA. These sublibraries were arrayed on filters at high density. In our approach, the MYAC 13 sublibrary is screened by hybridization with cytogenetically assigned Chr 13 DNA probes to select one or a small subset of MYACs. Inter-Alu PCR products from each MYAC are then hybridized to the MYAC and mYAC sublibraries to identify overlapping YACs and to an arrayed Chr 13-specific cosmid library to select corresponding cosmids. The set of selected cosmids, gridded on filters at high density, is hybridized with inter-Alu PCR products from each of the overlapping YACs to identify subsets of cosmids and also with riboprobes from each cosmid of the arrayed set ("cosmid matrix cross-hybridization"). From these data, cosmid contigs are assembled by a specifically designed computer program. Application of this method generates cosmid contigs spanning the length of a MYAC with few gaps. To provide a high-resolution map, ends of cosmids are sequenced at preselected sites to position densely spaced sequence-tagged sites.

Regional localization of 32 NotI-HindIII fragments from a human chromosome 13 library by a somatic cell hybrid panel and in situ hybridization

Relatively few DNA probes have been regionally assigned to chromosome 13 bands, and these tend to be clustered in the proximal end of the chromosome in the regions where intensive mapping efforts have been focused because of the retinoblastoma and Wilson disease genes. We have developed a chromosome 13-specific half-linking library of NotI-HindIII fragments and regionally mapped 32 of these on chromosome 13, using a somatic cell hybrid panel that subdivides chromosome 13 into 11 regions and nonisotopic in situ hybridization with silver amplification of a digoxigenin-labeled probe.

Homogeneously staining region in anthracycline-resistant HL-60/AR cells not associated with MDR1 amplification

Anthracycline-resistant HL-60/AR cells and their drug-sensitive HL-60/S counterparts were characterized by karyotypic analysis and examined for the overexpression of DNA and mRNA sequences coding for P-glycoprotein (Pgp). The HL-60/S cells were karyotypically stable over a 5-year period of study (1986-1991), except for an additional small Giemsa-positive band noted at 7q22 in cultures harvested in 1987, but not in 1986. This change did not affect drug sensitivity. The drug-resistant HL-60/AR cells examined in 1986, 1987, and 1991 demonstrated a very stable karyotype. The most striking feature was a large homogeneously staining region in the long arm of chromosome 7 (7q11.2), and translocation of the remainder of the long arm to another centromere. Other changes in the HL-60/AR cells included inversion in 9q, partial deletion of the short arm of chromosome 10p, addition of material to the p arm of der(16), loss of chromosome 22, and the appearance of a new marker chromosome. Both HL-60/S and the HL-60/AR cells were found not to amplify DNA or mRNA sequences coding for the Pgp. Thus, although the HL-60/AR cells possess the classical multidrug resistance phenotype and demonstrate a homogeneously staining region near the region of the MDR1 gene, their resistance is due to mechanisms other than those coded for by MDR1.

A shuttle vector system for the investigation of immunoglobulin gene hypermutation: absence of enhanced mutability in intermediate B cell lines

Somatic hypermutation focused to the rearranged V(D)J segment of the immunoglobulin (Ig) loci contributes substantially to antibody gene diversification. However, neither the precise B cell subset subject to hypermutation nor the molecular mechanism(s) involved is known. One model proposes that Ig segments may be uniquely susceptible to DNA nicking and subsequent error-prone repair during a specific B cell developmental stage. We describe an SV40-based shuttle vector system for testing such a model. Plasmids containing two distinct Ig segments juxtaposed to the supF marker gene have been passaged through cell lines representing intermediate stages of B cell development, rescued and screened for marker gene mutations. To date we have not demonstrated enhanced supF mutation in any cell line examined, irrespective of the adjacent Ig segment. Thus, these cell lines exhibit normal DNA repair mechanisms and no evidence of increased endonuclease activity on the Ig segments tested. The feasibility of this system will allow similar experiments using other Ig target sequences exposed to a broader range of B cells.

The aminoquinazoline group as a replacement for the salicylamide group: the design and synthesis of a novel highly selective beta 1 adrenoceptor partial agonist

The high potency at beta 1 receptors, excellent selectivity (beta 1/beta 2) and high degree of agonism displayed by compounds such as 1 is believed to be due in part to the salicylamide side chain. Two conformations of salicylamide are known to exist in the crystal state (2 and 3), but ab initio calculations suggest that in the absence of crystal packing forces 2 should be more stable. The aminoquinazoline group was judged to be a good replacement for salicylamide in 1, and consequently the oxypropanolamine derivative 4 was prepared. 4 shows extremely high potency at the beta 1 receptor, and excellent beta 1/beta 2 selectivity. It has comparable in vitro activity to 1, although it displays a lower degree of agonism. These results suggest that in this system aminoquinazoline appears to be an excellent mimic of the salicylamide group.

c-myc hypermutation is ongoing in endemic, but not all Burkitt's lymphoma

Deregulation of c-myc oncogene secondary to chromosomal translocation appears to play an essential role in the genesis of both endemic (African) Burkitt's lymphoma (eBL) and sporadic Burkitt's lymphoma (sBL). In most eBL, mutations in or near exon 1 disrupt normal c-myc regulatory sites. We examined c-myc sequences from a patient with sBL and two patients with eBL to determine (1) whether mutation is ongoing as the tumor clone expands, (2) the nature of mutations in the protein-coding exons 2 and 3, and (3) the extent of c-myc hypermutation in the two clinical forms of BL. Using the polymerase chain reaction (PCR), we amplified segments of c-myc from bulk tumor samples, cloned the products into plasmid vectors, and sequenced multiple subclones of each segment. The mutation frequencies in the control (remission bone marrow) and sBL tumor subclones were 0.65 x 10(-4) and 3.0 x 10(-4) (mutations/base), respectively (P greater than .25). Subclones from the two eBLs exhibited mutation frequencies of 20 x 10(-4) and 16 x 10(-4), respectively (P less than .001 v control). In addition to the consensus mutations seen in one eBL, a random pattern of unshared mutations was observed throughout c-myc in both samples, demonstrating that mutations may be introduced in a stepwise fashion. We noted a clear excess of transitions over transversions (30:9), which is qualitatively similar to the pattern observed in diverse examples of eukaryotic gene mutation. These data demonstrate that c-myc hypermutation is an ongoing process as the eBL tumor clone expands, is qualitatively different from immunoglobulin gene hypermutation, and is not a universal feature of BL, perhaps reflecting the nature of the translocation or the stage of tumor cell maturation.

Monochromosomal rodent-human hybrids from microcell fusion of human lymphoblastoid cells containing an inserted dominant selectable marker

An improved system for the production of a series of rodent-human hybrids selectively retaining single human chromosomes marked in known locations is described. Such hybrids have significant applications in gene mapping and other genetic studies. Human lymphoblastoid lines were infected with the retroviral vector SP-1, which contains the bacterial his-D gene allowing mammalian cells to grow in the presence of histidinol. Microcell fusion of the infected lymphoblastoid cells with CHO cells was used to produce hybrids containing single human chromosomes retained by histidinol selection. Hybrids containing a single human chromosome 9 and a single human chromosome 19 are described. These have been characterized cytogenetically by G-banding, in situ hybridization, and Southern blot analysis.

Improved methods of direct and cultured chromosome preparations from chorionic villous samples

A new method is described for preparing direct mitotic chromosome spreads from chorionic villous samples, which has resulted in sufficiently high yields of well-banded metaphases to permit a complete standard chromosomal diagnosis in 20 of 20 cases. A method of establishing monolayer cultures from this material that can be harvested from 3 to 7 days after initiation is also presented.

Chromosomal DNA homologous to Herpes simplex virus 1 in a mouse L-cell line

Cytological hybridization in situ was used to identify chromosomes carrying DNA sequences homologous to Herpes simplex I (HSV-I) DNA in a HSV-transformed L-cell line. The L-cell karyotype, frequency of chromosome distribution, and possible homology to the normal chromosome complement are given. The major chromosomal sites for transcription of ribosomal RNA (rRNA) were also determined.

On the chromosomal location of 5.8S DNA in people and mice

The genes that transcribe 5.8S RNA in people and mice have been localized to the previously assigned sites for ribosomal DNA. No other sites of transcription for 5.8S RNA were detected.

The localization of mouse globin genes: a test of the effectiveness of hybridization in situ

Hybridization of rabbit reticulocyte mRNA to banded mouse chromosomes in situ labeled several regions, including the globin loci. Whereas the labeling was sufficient to detect unknowns in the globin size class, the chromosome assignments would be doubtful without some means of removing trace contaminants from the probe or of recognizing chromosomal regions to which they hybridize. Mammalian gene mapping by means of hybridization in situ might be feasible with probes cloned in microbial host-vector systems or with kinetic analysis of the hybridization process at every labeled site.

The site of 5S RNA genes in primates. I. The great apes

A major site of genes for 5S RNA has been localized in representative members of the family Pongidae by means of hybridization in situ. These genes are shown to be concentrated in the most distal bands of the primate chromosome arm homologous to human chromosome 1q.

Variation in ribosomal RNA gene number in mouse chromosomes

Hybridization of ¹²⁵-I-ribosomal RNA to mouse chromosomes in situ produced significant differences in grain count at known rDNA sites, depending on the strains from which they were derived. This is interpreted to mean that the number of rRNA genes in a given nucleolar chromosome, and in the entire genome, is polymorphic among strains and among outbred individuals.

Does the T-locus in the mouse include ribosomal DNA?

The proportion of rDNA in the mouse genome is shown to have no systematic relation to the T-locus genotype, and hybridization in situ with 125I-RNA does not label chromosome 17, which carries the T-locus. Thus rDNA need no longer be taken into account in explaining the unique properties of the alleles at this locus. The number of genes for rRNA precursor averaged 153 per haploid genome, but a large measure of individual variation is suggested.

The site of 5S RNA genes in human chromosome 1

The major site of genes for human 5S RNA is in the long arm of chromosome 1. We find no evidence of sites in other chromosomes; if such exist, they are much smaller than the site in 1q.

Location of the genes for 16S and 23S ribosomal RNA in the genetic map of Escherichia coli

By means of RNA-DNA hybridization with DNA from different merodiploids of Escherichia coli, the genes for 16S and 23S ribosomal RNA were found near minute 74 of the genetic map.