Current Response in Ca V 1.3-/- Mouse Vestibular and Cochlear Hair Cells

Signal transmission by sensory auditory and vestibular hair cells relies upon Ca²⁺-dependent exocytosis of glutamate. The Ca²⁺ current in mammalian inner ear hair cells is predominantly carried through Ca_V1.3 voltage-gated Ca²⁺ channels. Despite this, Ca_V1.3 deficient mice (Ca_V1.3^–/–) are deaf but do not show any obvious vestibular phenotype. Here, we compared the Ca²⁺ current (I_Ca) in auditory and vestibular hair cells from wild-type and Ca_V1.3^–/– mice, to assess whether differences in the size of the residual I_Ca could explain, at least in part, the two phenotypes. Using 5 mM extracellular Ca²⁺ and near-body temperature conditions, we investigated the cochlear primary sensory receptors inner hair cells (IHCs) and both type I and type II hair cells of the semicircular canals. We found that the residual I_Ca in both auditory and vestibular hair cells from Ca_V1.3^–/– mice was less than 20% (12–19%, depending on the hair cell type and age investigated) compared to controls, indicating a comparable expression of Ca_V1.3 Ca²⁺ channels in both sensory organs. We also showed that, different from IHCs, type I and type II hair cells from Ca_V1.3^–/– mice were able to acquire the adult-like K⁺ current profile in their basolateral membrane. Intercellular K⁺ accumulation was still present in Ca_V1.3^–/– mice during I_K,L activation, suggesting that the K⁺-based, non-exocytotic, afferent transmission is still functional in these mice. This non-vesicular mechanism might contribute to the apparent normal vestibular functions in Ca_V1.3^–/– mice.

OP0118 EFFECT OF WITHDRAWING ETANERCEPT OR METHOTREXATE ON PATIENT-REPORTED OUTCOMES IN RHEUMATOID ARTHRITIS PATIENTS IN REMISSION ON COMBINATION THERAPY: RESULTS FROM THE SEAM-RA TRIAL

Background:

Limited studies have assessed the effect of withdrawal of either methotrexate (MTX) or etanercept (ETN) on patient-reported outcomes (PROs) in rheumatoid arthritis (RA).

Objectives:

To evaluate the baseline and change in PROs following withdrawal of MTX or ETN in RA patients with sustained remission receiving combination ETN+MTX.

Methods:

Adult patients with RA on ETN+MTX and in remission (SDAI ≤3.3) for ≥12 months (including a 24-week, open-label, run-in period) were randomized to a 48-week double-blind period to receive ETN 50 mg weekly (N=101), oral MTX 10-25 mg weekly (N=101) or continue ETN+MTX (N=51). The primary endpoint was maintenance of SDAI remission without disease worsening (DW) at week 48 between ETN and MTX groups. Patients who experienced SDAI >11 at any time after randomization, or SDAI >3.3 and ≤11 during 2 consecutive or on 3 non-consecutive visits were considered to have DW and resumed ETN+MTX. PROs assessed were patient global assessment of disease activity (PtGA, 0-100 mm), patient joint pain (PtJP, 0-100 mm), Health Assessment Questionnaire-Disability Index (HAQ-DI), and the 36-item short-form health survey (SF-36) component and domain scores. A 2-sample t-test was used to compare the treatment differences between groups. A subgroup analysis for patients with DW was also performed (DW analysis set) and compared PROs between ETN vs MTX arms (ETN+MTX not shown given the small sample size).

Results:

Of the 253 patients randomized, 121 (47.8%) experienced DW and were included in the DW analysis set. Baseline demographics were generally balanced between the 3 treatment groups. Most patients were women (76.3%), White (87.0%), and with a mean age of 55.6 years. The mean (SD) MTX dose was 16.3 (4.69) mg and the mean (SD) duration of RA was 10.3 (7.8) years. At week 48, a significantly greater proportion of patients on ETN vs MTX monotherapy maintained SDAI remission (49.5% vs 28.7%; P=0.004) after therapy withdrawal. In the overall population, PtGA and PtJP scores were very low at baseline (PtGA–MTX: 4.4, ETN: 4.5, ETN+MTX: 3.5; PtJP–MTX: 4.9, ETN: 5.5, ETN+MTX: 3.5) and showed some worsening over the study period in all treatment groups, with a mean change at week 48 ranging from 5.0 to 10.0 units for PtGA and 3.7 to 8.1 units for PtJP. Patients on ETN had less worsening, with a nominally significant treatment difference observed between ETN and MTX monotherapy groups for PtGA at almost all timepoints, and for PtJP at weeks 12 and 36 (Figure). Mean HAQ-DI (MTX: 0.32; ETN: 0.26; ETN+MTX: 0.28) and SF-36 scores (physical component [PCS]–MTX: 52.1, ETN: 52.7, ETN+MTX: 52.3; mental component [MCS]–MTX: 55.5, ETN: 55.8, ETN+MTX: 57.1) at baseline show that patients had low disability and excellent health-related quality of life compared with normative values for the general non-RA population. HAQ-DI scores were well maintained at weeks 24 and 48 (change from baseline at week 48–MTX: 0.14; ETN: 0.15; ETN+MTX: 0.21). The SF-36 PCS, MCS, and domain scores decreased minimally from baseline with treatment differences that were not nominally significant between groups. Among patients with DW during the study, those on ETN showed less PtGA and PtJP worsening from baseline than those on MTX at weeks 12, 36, and 48 (Figure). Other PROs (HAQ-DI [change from baseline at week 24–ETN: 0.34; MTX: 0.21; at week 48–ETN: 0.15; MTX: 0.15], SF-36 PCS, MCS, and domain scores) showed a similar degree of worsening in both the MTX and ETN arms.

Conclusion:

In patients with sustained SDAI remission on ETN+MTX, mental and physical health as measured by SF-36 was comparable with that of the non-RA population. Withdrawal of ETN (MTX monotherapy) resulted in a greater worsening of PtGA and PtJP than withdrawal of MTX (ETN monotherapy), and patients on ETN monotherapy restored these scores close to baseline towards the end of the treatment period. These findings demonstrate that ETN monotherapy has a greater effect on maintaining overall patient assessment of disease and joint pain compared with MTX monotherapy.

Disclosure of Interests:

Jeffrey Curtis Speakers bureau: AbbVie, BMS, Gilead, Lilly, Novartis, Sanofi, Scipher, Amgen, Corrona, Janssen, Myriad, and Pfizer, Consultant of: AbbVie, BMS, Gilead, Lilly, Novartis, Sanofi, Scipher, Amgen, Corrona, Janssen, Myriad, and Pfizer, Grant/research support from: AbbVie, BMS, Gilead, Lilly, Novartis, Sanofi, Scipher, Amgen, Corrona, Janssen, Myriad, and Pfizer, Elaine Karis Shareholder of: Amgen Inc., Employee of: Amgen Inc., Vivian Bykerk Speakers bureau: Amgen, BMS, Gilead, Pfizer, Sanofi-Genzyme/Regeneron, Scipher Medicine, and UCB., Consultant of: Amgen, BMS, Gilead, Pfizer, Sanofi-Genzyme/Regeneron, Scipher Medicine, and UCB., Grant/research support from: Amgen and Novartis, Greg Kricorian Shareholder of: Amgen Inc., Employee of: Amgen Inc., Priscilla Yen Shareholder of: Amgen Inc., Employee of: Amgen Inc., Paul Emery Speakers bureau: AbbVie, BMS, Celltrion, Gilead, Lilly, MSD, Novartis, Pfizer, Roche, Samsung, Sandoz, and UCB., Consultant of: AbbVie, BMS, Celltrion, Gilead, Lilly, MSD, Novartis, Pfizer, Roche, Samsung, Sandoz, and UCB., Paul Haraoui Speakers bureau: AbbVie, Celgene, Janssen, Pfizer, and UCB., Consultant of: AbbVie, Amgen, BMS, Celgene, Eli Lilly, Janssen, Merck, Pfizer, Roche, Sandoz, Sanofi-Genzyme, and UCB., Grant/research support from: Roche, AbbVie, Amgen, Merck, and Pfizer, David Collier Shareholder of: Amgen Inc., Employee of: Amgen Inc., Brad Stolshek Shareholder of: Amgen Inc., Employee of: Amgen Inc.

Hair cell maturation is differentially regulated along the tonotopic axis of the mammalian cochlea

Key points

Outer hair cells (OHCs) enhance the sensitivity and the frequency tuning of the mammalian cochlea.

Similar to the primary sensory receptor, the inner hair cells (IHCs), the mature functional characteristics of OHCs are acquired before hearing onset.

We found that OHCs, like IHCs, fire spontaneous Ca²⁺‐induced action potentials (APs) during immature stages of development, which are driven by Ca_V1.3 Ca²⁺ channels.

We also showed that the development of low‐ and high‐frequency hair cells is differentially regulated during pre‐hearing stages, with the former cells being more strongly dependent on experience‐independent Ca²⁺ action potential activity.

Abstract

Sound amplification within the mammalian cochlea depends upon specialized hair cells, the outer hair cells (OHCs), which possess both sensory and motile capabilities. In various altricial rodents, OHCs become functionally competent from around postnatal day 7 (P7), before the primary sensory inner hair cells (IHCs), which become competent at about the onset of hearing (P12). The mechanisms responsible for the maturation of OHCs and their synaptic specialization remain poorly understood. We report that spontaneous Ca²⁺ activity in the immature cochlea, which is generated by Ca_V1.3 Ca²⁺ channels, differentially regulates the maturation of hair cells along the cochlea. Under near‐physiological recording conditions we found that, similar to IHCs, immature OHCs elicited spontaneous Ca²⁺ action potentials (APs), but only during the first few postnatal days. Genetic ablation of these APs in vivo, using Ca_V1.3^−/− mice, prevented the normal developmental acquisition of mature‐like basolateral membrane currents in low‐frequency (apical) hair cells, such as I_K,n (carried by KCNQ4 channels), I_SK2 and I_ACh (α9α10nAChRs) in OHCs and I_K,n and I_K,f (BK channels) in IHCs. Electromotility and prestin expression in OHCs were normal in Ca_V1.3^−/− mice. The maturation of high‐frequency (basal) hair cells was also affected in Ca_V1.3^−/− mice, but to a much lesser extent than apical cells. However, a characteristic feature in Ca_V1.3^−/− mice was the reduced hair cell size irrespective of their cochlear location. We conclude that the development of low‐ and high‐frequency hair cells is differentially regulated during development, with apical cells being more strongly dependent on experience‐independent Ca²⁺ APs.

Outer hair cells (OHCs) enhance the sensitivity and the frequency tuning of the mammalian cochlea.

Similar to the primary sensory receptor, the inner hair cells (IHCs), the mature functional characteristics of OHCs are acquired before hearing onset.

We found that OHCs, like IHCs, fire spontaneous Ca²⁺‐induced action potentials (APs) during immature stages of development, which are driven by Ca_V1.3 Ca²⁺ channels.

We also showed that the development of low‐ and high‐frequency hair cells is differentially regulated during pre‐hearing stages, with the former cells being more strongly dependent on experience‐independent Ca²⁺ action potential activity.

Identifying consumer's needs of health information technology through an innovative participatory design approach among English- and Spanish-speaking urban older adults

OBJECTIVES

We describe an innovative community-centered participatory design approach, Consumer-centered Participatory Design (C2PD), and the results of applying C2PD to design and develop a web-based fall prevention system.

METHODS

We conducted focus groups and design sessions with English- and Spanish-speaking community-dwelling older adults. Focus group data were summarized and used to inform the context of the design sessions. Descriptive content analysis methods were used to develop categorical descriptions of design session informant's needs related to information technology.

RESULTS

The C2PD approach enabled the assessment and identification of informant's needs of health information technology (HIT) that informed the development of a falls prevention system. We learned that our informants needed a system that provides variation in functions/content; differentiates between actionable/non-actionable information/structures; and contains sensory cues that support wide-ranging and complex tasks in a varied, simple, and clear interface to facilitate self-management.

CONCLUSIONS

The C2PD approach provides community-based organizations, academic researchers, and commercial entities with a systematic theoretically informed approach to develop HIT innovations. Our community-centered participatory design approach focuses on consumer's technology needs while taking into account core public health functions.

Dynamic MR imaging of the temporomandibular joint using a balanced steady-state free precession sequence at 3T

The aim of our project was to develop an MR imaging protocol for dynamic imaging of the TMJ. We imaged a total of 24 joints in 12 subjects. We developed an imaging protocol on a 3T system using the true FISP sequence that yielded an acceptable spatial and temporal resolution for dynamic MR imaging.

Familial mosaicism of del(Y) and inv del(Y)

Molecular cytogenetic investigation of a male proband showing oligozoospermia (OAT I-II degrees ) has led to the detection of a Y-chromosome mosaicism. This mosaicism consists of a deleted Y chromosome with deletion of most of the long-arm heterochromatin, including the PAR2, del(Y), and a Y chromosome, which, in addition to that deletion, shows a paracentric long-arm inversion, inv del(Y), with breakpoints in the DAZ gene cluster in deletion interval 6 and within the remainder of the long-arm heterochromatin of the Y. The Y mosaicism is not confined to the sterile proband but is also detected in both his father and his fertile brother. Interestingly, the percentage of inv del(Y) is highest (80%) in the proband showing oligozoospermia.

Time course for early adaptive responses to ultraviolet B light in the epidermis of SKH-1 mice

Hairless SKH-1 mice were exposed once to UVB light (180 mJ/cm2), and mechanistically important early adaptive responses in the epidermis were evaluated by immunohistochemical and morphological methods. Interrelationships in the time course for these UVB-induced responses were examined. The number of epidermal cells with DNA strand breaks (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling-positive cells) or with thymine dimers increased to maximal levels within 30 min after UVB. The number of cells with DNA strand breaks located specifically in the basal layer of the epidermis was increased substantially by 3-30 min after UVB and gradually increased further over the next 5.5 hours. DNA strand breaks specifically in the basal layer of the epidermis were increased maximally at 6 h after UVB. The number of epidermal cells with DNA strand breaks or thymine dimers decreased markedly between 12 and 36 h. Pyrimidine (6-4) pyrimidone photodimers (6-4 photoproducts) in isolated epidermal DNA were increased immediately after irradiation of the mice with UVB and decreased markedly during the next 6 h. Exposure to UVB caused a rapid 8-fold increase in the number of epidermal cells with the DNA mismatch repair protein, MSH2 (within 30-60 min), and the level of MSH2-positive cells remained elevated for at least 48 h. These observations suggest a possible role of MSH2 in the repair of UVB-induced DNA damage. The number of epidermal cells with wild-type p53 protein started to increase at 1 h after UVB exposure and reached maximal levels by 8-12 h. The number of p53-positive cells fell markedly between 24 and 48 h. The time course for UVB-induced increases in the number of p53-positive cells was paralleled very closely by the time course for UVB-induced increases in the number of cells with p21(WAF1/CIP1), increases in morphologically distinct apoptotic sunburn cells, and decreases in the number of epidermal cells with bromodeoxyuridine (BrdUrd) incorporation into DNA. Although the start of UVB-induced increases in the number of p21(WAF1/CIP1)-positive cells was similar to that for the increase in p53-positive cells and very high levels of p21(WAF1/CIP1)-positive cells were observed at 8-12 h, maximal increases in p21(WAF1/CIP1)-positive cells were not achieved until 24 h after UVB irradiation (approximately 12 h after the peak value for p53). Myeloperoxidase-positive epidermal cells started to increase by 30 min after UVB exposure, and maximal numbers of myeloperoxidase-positive epidermal cells were observed at 2 h after UVB (18-fold higher than in nonirradiated control mice). An increased level of epidermal peroxidase enzyme activity in the epidermis was also observed from 1 to 24 h after exposure of the mice to UVB. Although neutrophil infiltration into the epidermis was not seen after exposure to UVB, neutrophil infiltration into the dermis (inflammatory response) was observed from 4 to 144 h after UVB exposure. In contrast to the marked inhibitory effect of UVB on BrdUrd incorporation into the DNA of epidermal cells observed at 8-12 h after UVB irradiation (>90% inhibition), BrdUrd incorporation into the DNA of epidermal cells was markedly increased (approximately 30-fold increase in the number of BrdUrd-positive cells) at 48 h after UVB exposure, and increases in epidermal cell layers and epidermal thickness (hyperplasia) were also observed. These later effects were associated with regeneration of the damaged epidermis.

Effect of dietary curcumin and dibenzoylmethane on formation of 7,12-dimethylbenz[a]anthracene-induced mammary tumors and lymphomas/leukemias in Sencar mice

Female Sencar mice (6 weeks old) were administered 1 mg of 7,12-dimethylbenz[a]anthracene (DMBA) by oral gavage once a week for 5 weeks. At 20 weeks after the first dose of DMBA, 68% of mice developed mammary tumors (the average 1.08 tumors per mouse) and 45% had lymphomas/leukemias. Feeding 1% dibenzoylmethane (DBM) in AIN 76A diet, starting at 2 weeks before the first dose of DMBA and continuing until the end of the experiment, inhibited both the multiplicity and incidence of DMBA-induced mammary tumor by 97%. The incidence of lymphomas/leukemias was completely inhibited by 1% DBM diet. In contrast, feeding 2% curcumin diet had little or no effect on the incidence of mammary tumors, and the incidence of lymphomas/leukemias was reduced by 53%.

Inhibitory effect of black tea on the growth of established skin tumors in mice: effects on tumor size, apoptosis, mitosis and bromodeoxyuridine incorporation into DNA

Female CD-1 mice were initiated with a single topical application of 7,12-dimethylbenz[a]anthracene and promoted with 12-O-tetradecanoylphorbol-13-acetate. Mice with established papillomas were then treated with black tea or decaffeinated black tea (approximately 4 mg tea solids/ml) as the sole source of drinking fluid for 11-15 weeks. In four separate experiments, oral administration of black tea inhibited the growth of papillomas (increase in tumor volume/mouse) by an average of 35%, 37%, 41% and 48%, respectively. Studies with decaffeinated black tea gave inconsistent results. In one experiment, administration of decaffeinated black tea inhibited papilloma growth (increase in tumor volume/mouse) by 27%, but in two additional experiments papilloma growth was stimulated by 14% and 193%, respectively. In a separate experiment, skin tumors were generated by treating SKH-1 female mice with ultraviolet B light (UVB; 30 mJ/cm2) twice weekly for 22 weeks, after which UVB administration was stopped. Tumors were allowed to develop during the following 13 weeks, and tumor-bearing mice were then treated with black tea (6 mg/ml tea solids) as the drinking fluid for 11 weeks. In this experiment, tumor growth (increase in tumor volume/mouse) was inhibited by 70%. Histological examination revealed that tea-treated mice had a 58% decrease in the number of nonmalignant tumors (primarily keratoacanthomas)/mouse and a 54% decrease in the number of squamous cell carcinomas/mouse. In addition, administration of black tea decreased the volume per tumor by 60% for nonmalignant tumors and by 84% for carcinomas. Mechanistic studies with tumors from these mice revealed that administration of black tea decreased the bromodeoxyuridine labeling index in squamous cell papillomas, keratoacanthomas and squamous cell carcinomas by 56%, 45% and 35%, respectively, and the apoptosis index was increased by 44%, 100% and 95%, respectively. Administration of black tea decreased the mitotic index in keratoacanthomas and squamous cell carcinomas by 42% and 16%, respectively. The results indicate that oral administration of black tea to tumor-bearing mice inhibited proliferation and enhanced apoptosis in nonmalignant and malignant skin tumors.

Comparative mapping of Xp22 genes in hominoids--evolutionary linear instability of their Y homologues

Several genes located within or proximal to the human PAR in Xp22 have homologues on the Y chromosome and escape, or partly escape, inactivation. To study the evolution of Xp22 genes and their Y homologues, we applied multicolour fluorescence in situ hybridization (FISH) to comparatively map DNA probes for the genes ANT3, XG, ARSD, ARSE (CDPX), PRK, STS, KAL and AMEL to prometaphase chromosomes of the human species and hominoid apes. We demonstrate that the genes residing proximal to the PAR have a highly conserved order on the higher primate X chromosomes but show considerable rearrangements on the Y chromosomes of hominoids. These rearrangements cannot be traced back to a simple model involving only a single or a few evolutionary events. The linear instability of the Y chromosomes gives some insight into the evolutionary isolation of large parts of the Y chromosomes and thus might reflect the isolated evolutionary history of the primate species over millions of years.

Enhanced skin carcinogenesis in transgenic mice with high expression of glutathione peroxidase or both glutathione peroxidase and superoxide dismutase

Female transgenic mice (C57BL/6 x CBA/J)F1 with a 1-fold increase in expression of glutathione peroxidase (GP) or with a 1-fold increase in the expression of GP and a 3-4-fold increase in the expression of superoxide dismutase (SOD) had an enhanced carcinogenic response to initiation by 7,12-dimethylbenz[a]anthracene (DMBA) followed by promotion with 12-O-tetradecanoylphorbol-13-acetate (TPA). GP- or GP+SOD-transgenic mice that were initiated by a single topical application of 200 nmol of DMBA followed by promotion with 8 nmol of TPA twice weekly for 30 weeks developed an average of 10.9 or 11.0 skin tumors per mouse and a 100% tumor incidence in comparison with the corresponding nontransgenic mice, which had 3.9 tumors per mouse and an 83% tumor incidence. After stopping TPA application, partial skin tumor regression occurred more rapidly in nontransgenic mice than in either type of transgenic mouse. At 10 weeks after termination of TPA treatment, 9-11% of the tumor-bearing transgenic mice and 26% of the tumor-bearing nontransgenic mice had complete regression of their tumors. Histopathological examination of 96 skin papillomas revealed that the area, location, degree of tumor dysplasia, bromodeoxyuridine labeling index, and p53 protein levels were closely intercorrelated. Further analysis indicated that papillomas with the same grade of dysplasia had a higher bromodeoxyuridine labeling index and a greater p53 protein level in GP- or GP+SOD-transgenic mice than those in nontransgenic mice. The data indicated that overexpression of skin antioxidant enzymes GP or GP+SOD, which are enzymes that are believed to protect cells from oxidative damage by scavenging reactive oxygen species, lead to the increased, rather than the decreased, tumorigenesis in a DMBA/TPA two-stage skin carcinogenesis model.

Inhibitory effects of topical application of low doses of curcumin on 12-O-tetradecanoylphorbol-13-acetate-induced tumor promotion and oxidized DNA bases in mouse epidermis

The effects of topical applications of very low doses of curcumin (the major yellow pigment in turmeric and the Indian food curry) on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced oxidation of DNA bases in the epidermis and on tumor promotion in mouse skin were investigated. CD-1 mice were treated topically with 200 nmol of 7,12-dimethylbenz[a]anthracene followed one week later by 5 nmol of TPA alone or together with 1, 10, 100 or 3000 nmol of curcumin twice a week for 20 weeks. Curcumin-mediated effects on TPA-induced formation of the oxidized DNA base 5-hydroxymethyl-2'-deoxyuridine (HMdU) and tumor formation were determined. All dose levels of curcumin inhibited the mean values of TPA-induced HMdU formation in epidermal DNA (62-77% inhibition), but only the two highest doses of curcumin strongly inhibited TPA-induced tumor promotion (62-79% inhibition of tumors per mouse and tumor volume per mouse). In a second experiment, topical application of 20 or 100 nmol (but not 10 nmol) of curcumin together with 5 nmol TPA twice a week for 18 weeks markedly inhibited TPA-induced tumor promotion. Curcumin had a strong inhibitory effect on DNA and RNA synthesis (IC50 = 0.5-1 microM) in cultured HeLa cells, but there was little or no effect on protein synthesis.

Genomic structure of a Y-specific ribonucleic acid binding motif-containing gene: a putative candidate for a subset of male infertility

The genetic basis of infertility remains unclear in a majority of infertile men. Deletion mapping studies suggest that genes on the long arm of the Y-chromosome (Yq) may be important in the spermatogenic process and may play a pathogenetic role in a subset of infertile men. Complementary DNA sequences of two Y-specific genes that contain ribonucleic acid binding motifs and, therefore, referred to as RBM genes (previously named YRRM) were published recently. To develop a PCR-single strand conformation polymorphism strategy for detection of point mutations in the RBM gene(s) in infertile men, we determined the genomic structure and flanking sequences at the intron-exon junctions. Two separate strategies were used in parallel to isolate the genomic fragment bearing the RBM gene. The first strategy employed screening of a P1 genomic library using PCR primers corresponding to the sequences in the 5'- and 3'-ends of the published RBM-1 complementary DNA sequence. The second strategy used subcloning of the YAC clone 925D10 (that contained the RBM gene described here) into cosmids. The P1 and cosmid clones were further restriction mapped and subcloned for DNA sequencing. Because the sequences contained in the P1 and cosmid clones were identical, the sequence information was pooled. A 15-kilobase genomic segment includes the entire RBM gene. The genomic structure of this RBM gene is characterized by 12 exons and 11 introns. There is considerable homology among exons VII, VIII, IX, and X; each encodes one of the SRGY boxes. Several introns also have a high degree of homology among them (introns VI, VII, VIII, and IX). Eleven of the 12 exons have complete sequence homology with the RBM-1 sequence. There is 1 base difference in exon IV at position 495 (a T in the previously published DNA sequence vs. an A in the sequence reported here). The exonic sequences of this gene are distinct from that of the RBM-2 gene. The flanking sequences at the exon-intron junctions were also determined and are reported. Reverse transcription-PCR analysis, using human testis ribonucleic acid suggests that this gene is either not expressed in the testis or, more likely, the single base difference from RBM1 represents a polymorphism in the YAC clone. A high degree of homology between intronic and exonic sequences within the same gene and between different members of the RBM gene family (data not reported in this paper) suggests origin from common ancestral sequences; this also indicates that development of a single strand conformation polymorphism approach for detection of point mutations is likely to prove difficult for some of the exons of this gene.

Sparse-wavelength angle-multiplexed volume holographic memory system: analysis and advances

We present and analyze our hybrid wavelength-and-angle-multiplexed volume holographic memory system. The hybridization of wavelength and angle multiplexing relaxes demands on spectral-tuning sources, angle-tuning devices, and optical system numerical apertures while maintaining a large K-space addressability. We consider realistic properties of our volume holographic memory system, addressing practical issues such as storage density and material-dependent photon-limited information throughput. Finally, we present experimental results of the storage of 2000 sparse-wavelength angle-multiplexed volume holograms in a 1.86-cm3 volume of lithium niobate.

Substantial prevalence of microdeletions of the Y-chromosome in infertile men with idiopathic azoospermia and oligozoospermia detected using a sequence-tagged site-based mapping strategy

Genes on the long arm of Y (Yq), particularly within interval 6, are believed to play a critical role in human spermatogenesis. Cytogenetically detectable deletions of this region are associated with azoospermia in men, but are relatively uncommon. It has been hypothesized that microdeletions of Yq may account for a significant proportion of men with infertility. The objective of this study was to validate a sequence-tagged site (STS)-mapping strategy for the detection of Yq microdeletions and to use this method to determine the proportion of men with idiopathic azoospermia or severe oligozoospermia who carry microdeletions in Yq. STS mapping of a sufficiently large sample of infertile men should also help further localize the putative gene(s) involved in the pathogenesis of male infertility. Genomic DNA was extracted from peripheral leukocytes of 16 normal fertile men, 7 normal fertile women, 60 infertile men (50 of whom had azoospermia and 10 of whom had severe oligozoospermia with no other recognizable cause of infertility), and 15 patients with the X-linked disorder, ichthyosis. PCR primers were synthesized for 26 STSs that span Yq interval 6. None of the 16 normal men of known fertility had microdeletions. Seven normal fertile women failed to amplify any of the 26 STSs, providing evidence of their Y specificity. No microdeletions were detected in any of the 15 patients with ichthyosis. Of the 60 infertile men typed with 26 STSs, 11 (18%; 10 azoospermic and 1 oligozoospermic) failed to amplify 1 or more STS. Interestingly, 4 of the 11 patients had microdeletions in a region that is outside the Yq region from which the DAZ (deleted in azoospermia gene region) gene was cloned. In an additional 3 patients, microdeletions were present both inside and outside the DAZ region. In 3 subjects, the microdeletions were verified by Southern analysis using labeled PCR products corresponding to the deleted STSs as probes. These data suggest a high prevalence (18%) of Yq microdeletions in men with idiopathic azoospermia/severe oligospermia. The physical locations of these microdeletions provide further support for the concept that a gene(s) on Yq deletion interval 6 plays an important role in spermatogenesis. The presence of deletions that do not overlap with the DAZ region suggests that genes other than the DAZ gene may also be implicated in the pathogenesis of some subsets of male infertility.

Inhibitory effects of caffeic acid phenethyl ester (CAPE) on 12-O-tetradecanoylphorbol-13-acetate-induced tumor promotion in mouse skin and the synthesis of DNA, RNA and protein in HeLa cells

Topical application of caffeic acid phenethyl ester (CAPE), a constituent of the propolis of honeybee hives, to the backs of CD-1 mice previously initiated with 7,12-dimethylbenz[a]anthracene (DMBA) inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced tumor promotion and the formation of 5-hydroxymethyl-2'-deoxyuridine (HMdU) in epidermal DNA. Topical application of 5 nmol TPA twice weekly for 20 weeks to mice previously initiated with 200 nmol of DMBA resulted in 18.8 skin papillomas per mouse. Topical application of 1, 10, 100 or 3000 nmol of CAPE together with 5 nmol of TPA twice a week for 20 weeks inhibited the number of skin papillomas per mouse by 24, 30, 45 or 70%, respectively, and tumor size per mouse was decreased by 42, 66, 53 or 74%, respectively. Topical application of 5 nmol of TPA twice weekly for 20 weeks to mice previously initiated with DMBA produced an average of 12.6 HMdU residues per 10(4) normal bases in epidermal DNA. Topical application of 1, 10, 100 or 3000 nmol of CAPE with 5 nmol of TPA twice weekly for 20 weeks to DMBA-initiated mice decreased the level of HMdU in epidermal DNA by 40-93%. The in vitro addition of 1.25, 2.5, 5, 10 or 20 microM CAPE to cultured HeLa cells inhibited the synthesis of DNA by 32, 44, 66, 79 or 95%, respectively, the synthesis of RNA was inhibited by 39, 43, 58, 64 or 75%, respectively, and the synthesis of protein was inhibited by 29, 30, 37, 32 or 47%, respectively. The results indicate a potent inhibitory effect of CAPE on TPA-induced tumor promotion and TPA-induced formation of HMdU in DNA of mouse skin as well as an inhibitory effect of CAPE on the synthesis of DNA, RNA and protein in culture HeLa cells.

Characterization of the promoter region of human steroid sulfatase: a gene which escapes X inactivation

The human X-linked steroid sulfatase gene (STS) was among the first genes shown to escape X inactivation. At least fourteen genes regulated in this fashion have now been recognized. They are dispersed into several regions of the X chromosome and may be controlled in a locus specific manner. Studies of the promoters of these genes could provide insights into the mechanism of X inactivation, however little information of this nature is currently available. For this reason we examined 5' flanking sequences of the human STS gene for promoter function. Four transcription start sites scattered over a 50bp region were identified. Functional domains of this TATA-less and GC poor promoter were identified by study of a series of terminal and internal deletions. A putative promoter sequence was identified which by itself exhibits little or no basal activity. However when combined with upstream regulatory elements, this segment showed weak but reproducible activity in a CAT (chloramphenicol acetyltransferase) reporter assay. Several regulatory domains acting as enhancers and repressors were subsequently identified. The relationship of this 5' sequence to the ability of the STS gene to escape X-inactivation is discussed.

Isolation and characterization of XE169, a novel human gene that escapes X-inactivation

Overlapping cDNA clones for a novel human X-linked gene, XE169, have been isolated and characterized. The composite cDNA sequence comprises 5910 bp (or 5901 bp) plus a poly(A) tail, with a 531 bp 5' and 696 bp 3' untranslated regions. The sequence represents a full-length or near full-length cDNA for the gene since Northern blot analysis reveals only a single prominent band approximately 6 kb in size. Alternative splicing generates two distinct transcripts either containing or missing a stretch of nine nucleotides in the XE169 single large open reading frame, which in turn predict two XE169 protein isoforms composed of 1557 and 1560 amino acids, respectively. Southern hybridization analysis of a panel of human-mouse somatic cell hybrids containing various portions of translocated human X chromosomes has assigned XE169 to the proximal half of the X short arm between Xp21.1 and the centromere. XE169 is expressed in multiple human tissues tested and homologous sequences exist on the human Y chromosome and in the genomes of five other eutherian mammals examined. RT-PCR analysis of somatic cell hybrids containing either an active or an inactive human X chromosome on a rodent background demonstrated that XE169 escapes X-inactivation.

Directed isolation of human genes that escape X inactivation

Existing methodologies have been combined to produce a directed approach to the isolation of human genes that escape X inactivation. A mouse-human somatic cell hybrid line was established that has an inactive X as its only human chromosome, and nuclear RNA from this cell line was used to construct a cDNA library. Transcribed human sequences were isolated by screening the library with labeled human DNA. The corresponding genomic sequences were isolated in phage or cosmid clones, and exons were identified by detection of transcripts on northern blots. By these means three human loci have been identified that contain genes expressed from an inactive X chromosome. Fluorescence in situ hybridization has been used to map these genes to Xp21.1-22.1, Xp22.1-22.2, and terminal Xp/Yp. One of the three genes (XE45) corresponds to the ZFX gene, while the other two genes (XE7 and XE59) represent novel cloned sequences. Physical and genetic evidence indicate that XE7 is a newly identified pseudoautosomal gene.

Isolation and characterization of a yeast artificial chromosome (YAC) contig around the human steroid sulfatase gene

The region surrounding the steroid sulfatase (STS) locus on Xp22.3 is of particular interest since it represents a deletion hot spot, shares homology with the proximal long arm of the Y chromosome (Yq11.2), and contains genes for several well-described X-linked disorders. Here we describe yeast artificial chromosomes (YACs) covering 450 kb around the STS gene. Eight YAC clones were isolated from a human YAC library. Their STS exon content was determined and the overlap of the clones characterized. Two of the YAC clones were found to contain the entire STS gene. The most proximal and the most distal ends of the YAC contig were cloned but neither of them crossed the breakpoints in any of the previously described patients with entire STS gene deletions. This is consistent with deletions larger than 500 kb in all these patients. One of the YAC clones was found to contain sequences from the STS pseudogene on Yq11.2. Two anonymous DNA sequences, GMGXY19 and GMGXY3, previously mapped in the vicinity of the STS locus, were found within the YAC contig and their assignment with respect to the STS locus was thus possible. This contig is useful for the overlap cloning of the Xp22.3 region and for reverse genetic strategies for the isolation of disease genes in the region. Furthermore, it may provide insight into the molecular mechanisms of deletion and translocation events on Xp22.3 and in the evolution of sex chromosomes.

Evolution of the pseudoautosomal boundary in Old World monkeys and great apes

Mammalian sex chromosomes are divided into sex-specific and pseudoautosomal regions. Sequences in the pseudoautosomal region recombine between the sex chromosomes; the sex-specific sequences normally do not. The interface between sex-specific and pseudoautosomal sequences is the pseudoautosomal boundary. The boundary is the centromeric limit to recombination in the pseudoautosomal region. In man, an Alu repeat element is found inserted at the boundary on the Y chromosome. In the evolutionary comparison conducted here, the Alu repeat element is found at the Y boundary in great apes, but it is not found there in two Old World monkeys. During the evolution of the Old World monkey and great ape lineages, homology between the sex chromosomes was maintained by recombination in the sequences telomeric to the Alu insertion site. The Alu repeat element did not create the present-day boundary; instead, it inserted at the preexisting boundary after the Old World monkey and great ape lineages diverged.

A long range restriction map of the distal human X chromosome short arm around the steroid sulfatase locus

The distal short arm of the human X chromosome is of interest because it contains genes which escape X chromosome inactivation and because it is subject to frequent deletions in human patients. The steroid sulfatase gene has been particularly well studied as an example of a gene which escapes X inactivation and which is included in a number of these deletion events. For these reasons a physical map of the region around the STS gene would be of interest. We have constructed a rare cutting enzyme map of this area and have determined the position of several nearby markers with respect to STS. We have also oriented the 5' and 3' ends of the STS gene on this map and have determined the centromeric and telomeric portions of the region. Finally, we have shown that this map can be used to locate deletion breakpoints in STS deficient patients.

Molecular studies of deletions at the human steroid sulfatase locus

The human steroid sulfatase gene (STS) is located on the distal X chromosome short arm close to the pseudoautosomal region but in a segment of DNA that is unique to the X chromosome. In contrast to most X chromosome-encoded genes, STS expression is not extinguished during the process of X chromosome inactivation. Deficiency of STS (steryl-sulfatase; steryl-sulfate sulfohydrolase, EC 3.1.6.2) activity produces the syndrome of X chromosome-linked ichthyosis, which is one of the most common inborn errors of metabolism in man. Approximately 90% of STS- individuals have large deletions at the STS locus. We and others have found that the end points of such deletions are heterogeneous in their location. One recently ascertained subject was observed to have a 40-kilobase deletion that is entirely intragenic, permitting the cloning and sequencing of the deletion junction. Studies of this patient and of other X chromosome sequences in other subjects permit some insight into the mechanism(s) responsible for generating frequent deletions on the short arm of the X chromosome.

Transformation with DNA from 5-azacytidine-reactivated X chromosomes

It has been shown that 5-azacytidine (5-Aza-Cyd) can reactivate genes on the inactive human X chromosome. It is assumed that the 5-Aza-Cyd acts by causing demethylation of the DNA at specific sites, but this cannot be demonstrated directly without a cloned probe. Instead, we have utilized the technique of DNA-mediated transformation to show that the 5-Aza-Cyd-induced reactivation occurs at the DNA level. DNAs from various mouse-human or hamster-human hybrid cell lines, deficient for mouse or hamster hypoxanthine phosphoribosyltransferase (HPRT, EC 2.4.2.8) and varying in whether they contained either an active or inactive human X chromosome, were used in transformation of HPRT- cells. DNA from the active human X chromosome-containing cell lines yielded HPRT+ transformants, whereas DNA from the inactive X chromosome-containing cells lines did not. The inactive X chromosomal DNA was able to transform thymidine kinase-deficient mouse cells, indicating that the DNA solution was normal. These results confirm that inactivation of the X chromosome involves a DNA modification. Furthermore, DNAs from three cell lines with a 5-Aza-Cyd-reactivated X chromosome also transform HPRT- cells, demonstrating that the 5-Aza-Cyd has altered the DNA structure and supporting the idea that methylation plays a role in X chromosome inactivation.