Identification and characterization of two androgen response regions in the human neutral endopeptidase gene

Transcription of the human neutral endopeptidase 24.11 (NEP) gene is androgen regulated in prostate cancer cells. Homology search identified a sequence GTCACAaagAGTTCT similar to the ARE consensus sequence GGTACAnnnTGTTCT within the 3'-untranslated region of the NEP mRNA. A double-stranded radiolabelled oligonucleotide containing this NEP-ARE sequence formed a DNA-protein complex with nuclear proteins from LNCaP cells or COS-7 cells co-transfected with an androgen receptor (AR) expression vector, and with full-length AR synthesized by baculovirus in mobility shift assays. Unlabeled NEP-ARE or consensus ARE but not mutated NEP-ARE replaced radiolabelled NEP-ARE. Steroid-dependent enhancement of transcription was assayed by transfecting ptkCAT reporter constructs containing the NEP-ARE into CV-1/AR cells and prostate cancer cells (PC-3/AR). Enhancement of chloramphenicol acetyltransferase (CAT) activity was increased four-fold by androgen, seven-fold by dexamethasone and three-fold by progesterone in CV-1/AR cells, and the NEP-ARE bound to glucocorticoid and progesterone receptor in mobility shift assays. We next performed DNase-I footprinting analysis of the NEP promoter and identified a 23 bp sequence GGTGCGGGTCGGAGGGATGCCCA (NEP-ARR) which was protected from DNase I cleavage by nuclear extracts from COS-7 cells expressing AR. This sequence was 62.5% homologous to an androgen responsive region (PSA-ARR) identified in the promoter of the prostate specific antigen (PSA) gene. A double-stranded radiolabelled oligonucleotide containing this NEP-ARR sequence formed DNA-protein complex with AR but not GR proteins. Unlabeled NEP-ARR, PSA-ARR and NEP-ARE replaced radiolabelled NEP-ARR. Steroid-dependent enhancement of transcription assays in PC-3/AR cells revealed that the enhancement of CAT activity was increased 2.3-fold by androgen, but not by glucocorticoid or progesterone. In a thymidine kinase promoter, the NEP-ARE and NEP-ARR together stimulated a five-fold increase in promoter activity in PC cells. These data suggest that steroid regulation of the NEP gene involves at least two elements including a typical ARE which binds androgen, progesterone and glucocorticoid receptors, and a unique ARR which only binds androgen receptor.

Neutral endopeptidase inhibits prostate cancer cell migration by blocking focal adhesion kinase signaling

Neutral endopeptidase 24.11 (NEP, CD10) is a cell-surface enzyme expressed by prostatic epithelial cells that cleaves and inactivates neuropeptides implicated in the growth of androgen-independent prostate cancer (PC). NEP substrates such as bombesin and endothelin-1 induce cell migration. We investigated the mechanisms of NEP regulation of cell migration in PC cells, including regulation of phosphorylation on tyrosine of focal adhesion kinase (FAK). Western analyses and cell migration assays revealed an inverse correlation between NEP expression and the levels of FAK phosphorylation and cell migration in PC cell lines. Constitutively expressed NEP, recombinant NEP, and induced NEP expression using a tetracycline-repressive expression system inhibited bombesin- and endothelin-1-stimulated FAK phosphorylation and cell migration. This results from NEP-induced inhibition of neuropeptide-stimulated association of FAK with cSrc protein. Expression of a mutated catalytically inactive NEP protein also resulted in partial inhibition of FAK phosphorylation and cell migration. Coimmunoprecipitation experiments show that NEP associates with tyrosine-phosphorylated Lyn kinase, which then binds the p85 subunit of phosphatidylinositol 3-kinase (PI3-K) resulting in an NEP-Lyn-PI3-K protein complex. This complex competitively blocks FAK-PI3-K interaction, suggesting that NEP protein inhibits cell migration via a protein-protein interaction independent of its catalytic function. These experiments demonstrate that NEP can inhibit FAK phosphorylation on tyrosine and PC cell migration through multiple pathways and suggest that cell migration which contributes to invasion and metastases in PC cells can be regulated by NEP.

Pulmonary complications in patients with AIDS: a report from a Beijing hospital

OBJECTIVE

The aim of this study was to improve the awareness of pulmonary complications in patients with AIDS.

METHODOLOGY

Nine patients with AIDS with pulmonary involvement from March 1992 to March 2000 were analysed.

RESULTS

Of the nine cases, there were eight cases complicated with Pneumocystis carinii pneumonia (PCP). The clinical presentation of PCP was fever (8/8), dyspnoea on exertion or at rest (7/8), and hypoxaemia with a mean PaO2 of 58 mmHg. Chest X-ray films showed bilateral diffuse interstitial or alveolar infiltrates. Pulmonary tuberculosis, tuberculous lymphadenitis and bronchial fungal infection were found in three cases.

CONCLUSIONS

AIDS patients are at high risk of suffering from pulmonary complications, of which PCP is most common. If young patients who were healthy in the past suddenly suffered from pneumonia and respiratory failure, PCP should be considered. When opportunistic pulmonary infection is diagnosed under special circumstances, one should be alert to the possibility of AIDS and examine serum antihuman immunodeficiency virus (HIV) antibody.

Neutral endopeptidase promotes phorbol ester-induced apoptosis in prostate cancer cells by inhibiting neuropeptide-induced protein kinase C delta degradation

Phorbol esters induce apoptosis in androgen-sensitive LNCaP cells, which express neutral endopeptidase (NEP), but not in androgen-independent prostate cancer (PC) cells, which lack NEP expression. We investigated the role of NEP in PC cell susceptibility to 12-O-tetradecanoylphorbol-13-acetate (TPA). Western analysis showed that expression of NEP and protein kinase Cdelta (PKCdelta) correlated with PC cell sensitivity to TPA-induced growth arrest and apoptosis in LNCaP cells and in TSU-Prl cells expressing an inducible wild-type NEP protein. Inhibition of NEP enzyme activity using the specific NEP inhibitor CGS24592, or inhibition of PKCdelta using Rottlerin at concentrations that inhibit PKCdelta but not PKCalpha, significantly inhibited TPA-induced growth inhibition and cell death. Furthermore, pulse-chase experiments showed PKCdelta is stabilized in LNCaP cells and in TSU-Pr1 cells overexpressing wild-type NEP compared with PC cells lacking NEP expression. This results from NEP inactivation of its neuropeptide substrates (bombesin and endothelin-1), which in the absence of NEP stimulate cSrc kinase activity and induce rapid degradation of PKCdelta protein. These results indicate that expression of enzymatically active NEP by PC cells is necessary for TPA-induced apoptosis, and that NEP inhibits neuropeptide-induced, cSrc-mediated PKCdelta degradation.

Myostatin and insulin-like growth factor-I and -II expression in the muscle of rats exposed to the microgravity environment of the NeuroLab space shuttle flight

The mechanism of the loss of skeletal muscle mass that occurs during spaceflight is not well understood. Myostatin has been proposed as a negative modulator of muscle mass, and IGF-I and IGF-II are known positive regulators of muscle differentiation and growth. We investigated whether muscle loss associated with spaceflight is accompanied by increased levels of myostatin and a reduction in IGF-I and -II levels in the muscle, and whether these changes correlate with an increase in muscle proteolysis and apoptosis. Twelve male adult rats sent on the 17-day NASA STS-90 NeuroLab space flight were divided upon return to earth into two groups, and killed either 1 day later (R1) or after 13 days of acclimatization (R13). Ground-based control rats were maintained for the same periods in either vivarium (R3 and R15, respectively), or flight-simulated cages (R5 and R17, respectively). RNA and protein were isolated from the tibialis anterior, biceps femoris, quadriceps, and gastrocnemius muscles. Myostatin, IGF-I, IGF-II and proteasome 2c mRNA concentrations were determined by reverse transcription/PCR; myostatin and ubiquitin mRNA were also measured by Northern blot analysis; myostatin protein was estimated by immunohistochemistry; the apoptotic index and the release of 3-methylhistidine were determined respectively by the TUNEL assay and by HPLC. Muscle weights were 19-24% lower in the R1 rats compared with the control R3 and R5 rats, but were not significantly different after the recovery period. The myostatin/beta-actin mRNA ratios (means+/-s.e.m. ) were higher in the muscles of the R1 rats compared with the control R5 rats: 5.0-fold in tibialis (5.35 +/- 1.85 vs 1.07 +/- 0.26), 3.0-fold in biceps (2.46+/-0.70 vs 0.81 +/- 0.04), 1.9-fold in quadriceps (7.84 +/- 1.73 vs 4.08 +/- 0.52), and 2.2-fold in gastrocnemius (0.99 +/- 0.35 vs 0.44 +/- 0.17). These values also normalized upon acclimatization. Our antibody against a myostatin peptide was validated by detection of the recombinant human myostatin protein on Western blots, which also showed that myostatin immunostaining was increased in muscle sections from R1 rats, compared with control R3 rats, and normalized upon acclimatization. In contrast, IGF-II mRNA concentrations in the muscles from R1 rats were 64-89% lower than those in R3 animals. With the exception of the gastrocnemius, IGF-II was also decreased in R5 animals maintained in flight-simulated cages, and normalized upon acclimatization. The intramuscular IGF-I mRNA levels were not significantly different between the spaceflight rats and the controls. No increase was found in the proteolysis markers 3-methyl histidine, ubiquitin mRNA, and proteasome 2C mRNA. In conclusion, the loss of skeletal muscle mass that occurs during spaceflight is associated with increased myostatin mRNA and protein levels in the skeletal muscle, and a decrease in IGF-II mRNA levels. These alterations are normalized upon restoration of normal gravity and caging conditions. These data suggest that reciprocal changes in the expression of myostatin and IGF-II may contribute to the multifactorial pathophysiology of muscle atrophy that occurs during spaceflight.

The protein tyrosine phosphatase Shp-2 regulates RhoA activity

Remodeling of filamentous actin into distinct arrangements is precisely controlled by members of the Rho family of small GTPases [1]. A well characterized member of this family is RhoA, whose activation results in reorganization of the cytoskeleton into thick actin stress fibers terminating in integrin-rich focal adhesions [2]. Regulation of RhoA is required to maintain adhesion in stationary cells, but is also critical for cell spreading and migration [3]. Despite its biological importance, the signaling events leading to RhoA activation are not fully understood. Several independent studies have implicated tyrosine phosphorylation as a critical event upstream of RhoA [4]. Consistent with this, our recent studies have demonstrated the existence of a protein tyrosine phosphatase (PTPase), sensitive to the dipeptide aldehyde calpeptin, acting upstream of RhoA [5]. Here we identify the SH2 (Src homology region 2)-containing PTPase Shp-2 as a calpeptin-sensitive PTPase, and show that calpeptin interferes with the catalytic activity of Shp-2 in vitro and with Shp-2 signaling in vivo. Finally, we show that perturbation of Shp-2 activity by a variety of genetic manipulations results in raised levels of active RhoA. Together, these studies identify Shp-2 as a PTPase acting upstream of RhoA to regulate its activity and contribute to the coordinated control of cell movement.

Interaction of retinoic acid and interferon in renal cancer cell lines

Retinoic acid (RA) can potentiate the antitumor effect of interferons (IFN) in a variety of tumor types, including renal cell carcinoma (RCC). The mechanisms by which RA and IFN increase the antitumor effects in RCC are unknown. We used growth assays and mobility shift assays to examine the effects of combining 13-cis-retinoic acid (CRA) and IFN-alpha (plus IFN-gamma) on proliferation and on the expression of the IFN-specific transcription factor IFN-stimulated gene factor 3 (ISGF3) in RCC cell lines. Combining CRA and IFN-alpha resulted in a significant increase in growth inhibition in four cell lines compared with IFN-alpha or CRA alone. Binding of nuclear extracts from RCC cells to an IFN-stimulated response element (ISRE) oligonucleotide probe following incubation with IFN-alpha was not increased by CRA but was significantly increased by pretreatment by IFN-gamma in a time-dependent fashion. Proliferation assays showed that sequential addition of IFN-gamma and IFN-alpha significantly increased growth inhibition. IFN-alpha but not IFN-gamma or CRA increased the cellular levels Stat2 and p48 but not Statl. IFN-gamma pretreatment enhanced the upregulation of p48 levels by IFN-alpha. Combining RA and IFN results in additive growth inhibition on RCC cell lines. This increase in growth inhibition is not mediated by increased ISGF3 expression.

Astrocytes contribute to the brain-metastatic specificity of melanoma cells by producing heparanase

Neurotrophins (NTs) modulate the brain invasion of melanoma cells and the activity of an extracellular matrix degradative enzyme, heparanase, that has been recently cloned. Heparanase degrades the heparan sulfate proteoglycans (HSPGs) and is a critical mediator of tumor metastasis and angiogenesis. Because astrocytes are among the first brain cells encountered by extravasating melanoma cells, they may play important roles in the development of brain metastases. To test this hypothesis, we used purified in vitro astrocyte cultures and found that they express heparanase transcript and functional enzyme that were up-regulated by the prototypic NT, nerve growth factor. Coincubation of astrocytes (or their conditioned medium) with brain-metastatic cells resulted in a superadditive effect on heparanase activity and up to an 8-fold increase of in vitro chemoinvasion using purified HSPGs. These observations indicate that astrocytes significantly contribute to the brain colonization of melanoma cells via heparanase-driven modalities.

4-Anilino-6,7-dialkoxyquinoline-3-carbonitrile inhibitors of epidermal growth factor receptor kinase and their bioisosteric relationship to the 4-anilino-6,7-dialkoxyquinazoline inhibitors

The synthesis and SAR of a series of 4-anilino-6, 7-dialkoxyquinoline-3-carbonitrile inhibitors of epidermal growth factor receptor (EGF-R) kinase are described. Condensation of 3, 4-dialkoxyanilines with ethyl (ethoxymethylene)cyanoacetate followed by thermal cyclization gave, regiospecifically, 6,7-dialkoxy-4-oxo-1, 4-dihydroquinoline-3-carbonitriles. Chlorination (POCl(3)) followed by the reaction with substituted anilines furnished the 4-anilino-6, 7-dialkoxyquinoline-3-carbonitrile inhibitors of EGF-R kinase. An alternate synthesis of these compounds starts with a methyl 3, 4-dialkoxybenzoate. Nitration followed by reduction (Fe, NH(4)Cl, MeOH-H(2)O) gave a methyl 2-amino-4,5-dialkoxybenzoate. Amidine formation using DMF-acetal followed by cyclization using LiCH(2)CN furnished a 6,7-dialkoxy-4-oxo-1,4-dihydroquinoline-3-carbonitrile, which was transformed as before. Compounds containing acid, ester, amide, carbinol, and aldehyde groups at the 3-position of the quinoline ring were also prepared for comparison, as were several 1-anilino-6,7-dimethoxyisoquinoline-4-carbonitriles. The compounds were evaluated for their ability to inhibit the autophosphorylation of the catalytic domain of EGF-R. The SAR of these inhibitors with respect to the nature of the 6,7-alkoxy groups, the aniline substituents, and the substituent at the 3-position was studied. The compounds were further evaluated for their ability to inhibit the growth of cell lines that overexpress EGF-R or HER-2. It was found that 4-anilinoquinoline-3-carbonitriles are effective inhibitors of EGF-R kinase with activity comparable to the 4-anilinoquinazoline-based inhibitors. A new homology model of EGF-R kinase was constructed based on the X-ray structures of Hck and FGF receptor-1 kinase. The model suggests that with the quinazoline-based inhibitors, the N3 atom is hydrogen-bonded to a water molecule which, in turn, interacts with Thr 830. It is proposed that the quinoline-3-carbonitriles bind in a similar manner where the water molecule is displaced by the cyano group which interacts with the same Thr residue.

Pharmacokinetics of a novel testosterone matrix transdermal system in healthy, premenopausal women and women infected with the human immunodeficiency virus

The clinical consequences of androgen deficiency in human immunodeficiency virus (HIV)-infected women remain underappreciated. The pharmacokinetics of transdermally administered testosterone in premenopausal women and HIV-infected women have not been studied. In this study we compared the pharmacokinetics of a novel testosterone matrix transdermal system (TMTDS) in healthy premenopausal women and women infected with HIV. Eight menstruating HIV-infected women, 18-50 yr of age, who had been receiving stable antiretroviral therapy, including a protease inhibitor, for at least 12 weeks and nine healthy, menstruating women of comparable age were enrolled. After baseline sampling during a 24-h control period in the early follicular phase (days 1-6), two TMTDS patches were applied with an expected delivery rate of 300 microg testosterone daily over an application period of 3-4 days. After 72 h, the patches were removed, a second set of two patches was applied, and blood samples were drawn over 96 h. Baseline serum total and free testosterone levels were lower in HIV-infected women than in healthy women. A diurnal rhythm of testosterone secretion, with higher levels in the morning and lower levels in the late afternoon, was apparent in both groups of women. Free testosterone levels were in the midnormal range at baseline in healthy women and increased above the upper limit of normal during TMTDS application. In HIV-infected women, free testosterone levels were in the low normal range at baseline and rose into the upper normal range during patch application. Serum total testosterone levels increased into the midnormal range in HIV-infected women and into the upper normal range in healthy women during patch application. The mean increments in free and total testosterone levels were significantly lower in HIV-infected women than in healthy women. Testosterone bioavailability, expressed as the mean +/- SEM baseline-subtracted area under the total testosterone curve, was significantly greater in healthy women than in HIV-infected women [3323 +/- 566 ng/dL x h (115 +/- 20 nmol/L x h) vs. 1506 +/- 316 ng/dL x h (52 +/- 11 nmol/ L x h); P = 0.016]. Assuming a daily testosterone delivery rate of 300 microg/day, the apparent plasma clearance was significantly higher in HIV-infected women than in healthy women (2531 +/- 469 vs. 1127 +/- 217 L/day1 P = 0.022), respectively. There was no significant change from baseline in serum LH, sex hormone-binding globulin, and estradiol levels in either group. Serum FSH levels showed a greater decrease from baseline in healthy women. A regimen of two testosterone patches applied twice a week can maintain serum total and free testosterone levels in the mid- to upper normal range, respectively, in HIV-infected women with low testosterone levels. During TMTDS application, the increments in serum total and free testosterone levels are lower in HIV-infected women than in healthy women, presumably due to increased plasma clearance or decreased absorption. Further studies are needed to assess the effects of physiological androgen replacement in HIV-infected women.

Recombinase-activating gene (RAG) 2-mediated V(D)J recombination is not essential for tumorigenesis in Atm-deficient mice

The majority of Atm-deficient mice die of malignant thymic lymphoma by 4-5 mo of age. Cytogenetic abnormalities in these tumors are consistently identified within the Tcr alpha/delta locus, suggesting that tumorigenesis is secondary to aberrant responses to double-stranded DNA breaks that occur during V(D)J recombination. Since V(D)J recombination is a recombinase-activating gene (RAG)-dependent process, we generated Rag2(-/-)Atm(-/-) mice to assess the requirement for RAG-dependent recombination in thymic lymphomagenesis. In contrast to expectation, the data presented here indicate that development of malignant thymic lymphoma in Atm(-/-) mice is not prevented by loss of RAG-2 and thus is not dependent on V(D)J recombination. Malignant thymic lymphomas in Rag2(-/-)Atm(-/-) mice occurred at a lower frequency and with a longer latency as compared with Atm(-/-) mice. Importantly, cytogenetic analysis of these tumors indicated that multiple chromosomal abnormalities occurred in each tumor, but that none of these involved the Tcr alpha/delta locus. Nonmalignant peripheral T cells from TCR-transgenic Rag2(-/-)Atm(-/-) mice also revealed a substantial increase in translocation frequency, suggesting that these translocations are early events in the process of tumorigenesis. These data are consistent with the hypothesis that the major mechanism of tumorigenesis in Atm(-/-) mice is via chromosomal translocations and other abnormalities that are secondary to aberrant responses to double-stranded DNA breaks. Furthermore, these data suggest that V(D)J recombination is a critical, but not essential, event during which Atm-deficient thymocytes are susceptible to developing chromosome aberrations that predispose to malignant transformation.

Glucagon-like peptide 2: a new treatment for chemotherapy-induced enteritis

BACKGROUND

Glucagon-like peptide 2 (GLP-2) is a recently identified intestinal epithelium-specific growth factor that has been shown to reduce the severity of inflammatory disorders of the intestine in rodent models. We hypothesized that GLP-2 administration would be beneficial in chemotherapy-induced enteritis either by preventing injury or by promoting recovery.

MATERIAL AND METHODS

Rats received no drug (control), chemotherapy alone [5-fluorouracil (5-FU), 190 mg/kg, ip] (Chemo), 5-FU followed by 3 days of GLP-2 analog (ALX-0600, 0.1 microg, sc twice daily) (CH-G), or GLP-2 analog for 6 days prior to 5-FU and for 3 days afterward (G-CH-G). Animals were pair fed. Rats received 5-bromo-2-deoxyuridine (Br-dU, 50 mg/kg, 2.5 h prior to sacrifice on Day 3 postchemotherapy) for immunohistochemical assessment of cellular proliferation.

RESULTS

Chemotherapy induced significant reductions in body weight, villus height, and crypt depth compared with controls. Intestinal wet weight, villus height, and crypt depth were significantly higher for the CH-G group compared with the Chemo group. The CH-G group also showed a significant improvement in villus height compared with the G-CH-G group. Crypt depth, but not jejunal wet weight or villus height, was significantly improved in the G-CH-G group compared with the Chemo group. The percentage of Br-dU-labeled cells in the intestinal crypts did not differ among the groups.

CONCLUSIONS

These results suggest, for the first time, that GLP-2 treatment initiated after chemotherapy administration enhances intestinal recovery. In contrast, GLP-2 treatment initiated prior to chemotherapy administration to prevent injury has less beneficial effect. GLP-2 administration may be beneficial to patients suffering from chemotherapy-induced enteritis.

Methylation of the neutral endopeptidase gene promoter in human prostate cancers

Neutral endopeptidase 24.11 (NEP) is a cell surface peptidase expressed by prostatic epithelial cells that cleaves and inactivates neuropeptide growth factors implicated in the growth of androgen-independent prostate cancer (PC). Decreased NEP expression in hormone-refractory metastatic PCs can result from hormonal therapies because NEP transcription is induced by androgens and down-regulated by androgen withdrawal. NEP is encoded by a gene that contains a 5' CpG island spanning a transcriptional regulatory region. In this study, we investigate whether DNA hypermethylation of the NEP promoter accompanies decreased NEP expression in PC cell lines and whether it occurs in human PC tissues in vivo. DNA isolated from PC cell lines and from normal and neoplastic human prostate tissues was restriction-digested with a methylation-sensitive restriction endonuclease and analyzed by Southern blot using a 5' sequence-specific NEP probe. Methylation-specific PCR was performed using PCR primers designed to discriminate between methylated and unmethylated alleles, and reverse transcription-PCR using NEP-specific primers was performed on cDNA extracted from PC cells treated with 5-aza-2'-deoxycytidine. Methylation of the NEP promoter was present in androgen-independent PC cell lines but not in androgen-dependent or small-cell derived PC cell lines and in 3 of 21 (14%) primary PCs from patients with androgen-dependent disease. Exposure of PC cells to the demethylating agent 5-aza-2'-deoxycytidine led to an increase in NEP transcripts in DU-145 and PC-3 cells. These data show that hypermethylation of the 5' CpG NEP island is associated with a loss of NEP expression in PC. Loss of NEP expression via hypermethylation of the NEP promoter may contribute to the development of neuropeptide-stimulated PCs.

Androgen-induced growth inhibition of androgen receptor expressing androgen-independent prostate cancer cells is mediated by increased levels of neutral endopeptidase

Androgen-mediated growth repression of androgen-independent prostate cancer (AIPC) cells has been reported in androgen-independent PC-3 cells overexpressing the androgen receptor, and in androgen-independent derivatives of LNCaP cells that develop following prolonged culture in androgen-free media. Using two models of AIPC, PC3/AR cells and LNCaP-OM1 cells, a subclone of LNCaP cells derived by prolonged culturing in charcoal-stripped media, we investigated whether expression of neutral endopeptidase 24.11 (NEP), a cell-surface peptidase that cleaves and inactivates neuropeptides implicated in the growth of AIPC, is induced by androgen, and whether NEP contributes to the observed androgen-mediated growth repression. These cell lines each express high levels of androgen receptor. Culturing in dihyrotestosterone (DHT) resulted in a 30-56% (PC3) and 35-43% (LNCaP-OM1) decrease in cell number over 7 days concomitant with a significant increase in NEP enzyme specific activity. Northern analysis detected an increase in NEP transcripts following DHT treatment in PC3/AR cells. The addition of the NEP enzyme inhibitor phosphoramidon to PC3 and LNCaP-OM1 or the NEP competitive inhibitor CGS 24592 to LNCaP-OM1 blocked the increase in NEP enzyme activity and reversed the DHT-induced growth inhibition. Neither phosphoramidon or CGS 24592 alone inhibited cell growth. Furthermore, the reversal of growth inhibition in LNCaPOM1 cells was dose dependent on the concentration of CGS 24592. These data indicate that androgen-induced growth repression of AIPC cells PC3 and LNCaP-OM1 results in part from androgen-induced expression of NEP in these cells.

Testosterone replacement and resistance exercise in HIV-infected men with weight loss and low testosterone levels

CONTEXT

Previous studies of testosterone supplementation in HIV-infected men failed to demonstrate improvement in muscle strength. The effects of resistance exercise combined with testosterone supplementation in HIV-infected men are unknown.

OBJECTIVE

To determine the effects of testosterone replacement with and without resistance exercise on muscle strength and body composition in HIV-infected men with low testosterone levels and weight loss.

DESIGN AND SETTING

Placebo-controlled, double-blind, randomized clinical trial conducted from September 1995 to July 1998 at a general clinical research center.

PARTICIPANTS

Sixty-one HIV-infected men aged 18 to 50 years with serum testosterone levels of less than 12.1 nmol/L (349 ng/dL) and weight loss of 5% or more in the previous 6 months, 49 of whom completed the study.

INTERVENTIONS

Participants were randomly assigned to 1 of 4 groups: placebo, no exercise (n = 14); testosterone enanthate (100 mg/wk intramuscularly), no exercise (n = 17); placebo and exercise (n = 15); or testosterone and exercise (n = 15). Treatment duration was 16 weeks.

MAIN OUTCOME MEASURES

Changes in muscle strength, body weight, thigh muscle volume, and lean body mass compared among the 4 treatment groups.

RESULTS

Body weight increased significantly by 2.6 kg (P<.001) in men receiving testosterone alone and by 2.2 kg (P = .02) in men who exercised alone but did not change in men receiving placebo alone (-0.5 kg; P = .55) or testosterone and exercise (0.7 kg; P = .08). Men treated with testosterone alone, exercise alone, or both experienced significant increases in maximum voluntary muscle strength in leg press (range, 22%-30%), leg curls (range, 18%-36%), bench press (range, 19%-33%), and latissimus pulls (range, 17%-33%). Gains in strength in all exercise categories were greater in men assigned to the testosterone-exercise group or to the exercise-alone group than in those assigned to the placebo-alone group. There was a greater increase in thigh muscle volume in men receiving testosterone alone (mean change, 40 cm3; P<.001 vs zero change) or exercise alone (62 cm3; P = .003) than in men receiving placebo alone (5 cm3; P = .70). Average lean body mass increased by 2.3 kg (P = .004) and 2.6 kg (P<.001), respectively, in men who received testosterone alone or testosterone and exercise but did not change in men receiving placebo alone (0.9 kg; P = .21). Hemoglobin levels increased in men receiving testosterone but not in those receiving placebo.

CONCLUSION

Our data suggest that testosterone and resistance exercise promote gains in body weight, muscle mass, muscle strength, and lean body mass in HIV-infected men with weight loss and low testosterone levels. Testosterone and exercise together did not produce greater gains than either intervention alone.

Analysis of the insertion/deletion polymorphism of the human angiotensin converting enzyme (ACE) gene in patients with renal cancer

The angiotensin I-converting enzyme (ACE) contains an insertion/deletion (I/D) polymorphism, with the DD genotype associated with benign renal diseases. The distribution frequencies of the D and I alleles, and the DD, DI and II genotypes were determined in DNA extracted from kidney tissues of 58 renal cancer patients. The observed frequencies in patients who develop renal cancer was not significantly different than the normal population.

Serum dihydrotestosterone and testosterone concentrations in human immunodeficiency virus-infected men with and without weight loss

Weight loss is an important determinant of disease outcome in human immunodeficiency virus (HIV)-infected men. Others have suggested that a defect in dihydrotestosterone (DHT) generation contributes to weight loss in HIV-infected men. To determine whether DHT levels correlate with weight loss independently of changes in testosterone levels, we prospectively measured serum total- and free-testosterone and DHT levels in 148 consecutive HIV-infected men and 42 healthy men. Thirty-one percent of HIV-infected men had serum testosterone levels less than 275 ng/dL, the lower limit of the normal male range; of these, 81% had normal or low LH and FSH levels (hypogonadotropic), and 19% had elevated LH and FSH levels (hypergonadotropic). Overall, serum testosterone, free-testosterone, and DHT levels were lower in HIV-infected men than in healthy men, but serum DHT-to-testosterone ratios were not significantly different between the two groups. Serum total- and free-testosterone levels were lower in HIV-infected men who had lost 5 lb or more of weight in the preceding 12 months than in those who had not lost any weight. Serum DHT levels and DHT-to-testosterone ratios did not differ between those who had lost weight and those who had not. Serum testosterone and free-testosterone levels, but not DHT levels, correlated with weight change and with Karnofsky performance status. We also performed a retrospective analysis of data from a previous study in which HIV-infected men with serum testosterone levels less than 400 ng/dL had been treated with placebo or testosterone patches designed to nominally release 5 mg testosterone over 24 hours. Serum testosterone-to-DHT ratios did not change after testosterone treatment. Changes in fat-free mass were correlated with changes in both serum testosterone (r = 0.42, P = 0.018) and DHT (r = 0.35, P = 0.049) levels. Serum total- testosterone and DHT levels were highly correlated with one another, and when the change in serum testosterone was taken into account, serum DHT levels no longer showed a significant correlation with change in fat-free mass. We conclude that DHT levels are lower in HIV-infected men than in healthy men but that neither DHT levels nor DHT-to-testosterone ratios correlate with weight loss. During testosterone treatment, serum DHT levels increase proportionately, but the increments in serum testosterone correlate with the change in fat-free mass. Our data do not support the hypothesis that a defect in DHT generation contributes to weight loss in HIV-infected men independently of changes in testosterone levels; it is possible that such a defect might exist in HIV-infected men with more severe weight loss.

A src-related kinase in the brush border membranes of gastrointestinal cells is regulated by c-met

Hepatocyte growth factor (HGF) elicits pleiotropic cellular responses by binding to c-met, a PTK transmembrane receptor. The recent identification of HGF in fluids which enter the gut lumen suggests a mechanism by which c-met molecules are accessible to ligand that is present near the apical surfaces of polarized enterocytes. A subset of c-met molecules was detected, by confocal and immunoelectron microscopic analysis, which colocalizes with a recently identified src-related gastrointestinal tyrosine kinase (gtk) in the brush border membranes of enterocytes. Furthermore, treatment of c-met/gtk-transfected cells with a chemical cross-linking agent revealed that c-met forms a physical complex with gtk, in vivo. Not surprisingly, activation of the receptor molecules with HGF rapidly stimulated gtk enzymatic activity. Similarly, the stimulation of gtk activity occurred when nontransfected primary hepatocytes were exposed to ligand. These findings suggest a model in which HGF binding to luminally accessible c-met stimulates gtk activity. This brush border-associated c-met-linked pathway may be associated with a defined set of epithelial cell responses.

Gab2, a new pleckstrin homology domain-containing adapter protein, acts to uncouple signaling from ERK kinase to Elk-1

We describe a novel human adapter molecule containing a pleckstrin homolgy (PH) domain at the N terminus that is closely related to human Grb2-associated binder 1, Gab1, and Drosophila daughter of sevenless. We designate this protein as Gab2. Northern blot analysis indicates that Gab2 is widely expressed and has an overlapping but distinctive expression pattern as compared with Gab1, with high levels of Gab2 mRNA detected in the heart, brain, placenta, spleen, ovary, peripheral blood leukocytes, and spinal cord. Upon tyrosine phosphorylation, Gab2 physically interacts with Shp2 tyrosine phosphatase and Grb2 adapter protein. Strikingly, Gab2 has an inhibitory effect on the activation of Elk-1-dependent transcription triggered by a dominant active Ras mutant (RasV12) or under growth factor stimulation, whereas Gab1 acts to potentiate slightly the Elk-1 activity in the same system. In contrast to the reciprocal effects of Gab1 and Gab2 in mediating Elk-1 induction, these two molecules have a similar function in extracellular signal-regulated kinase activation induced by either oncogenic Ras or growth factor stimulation. Taken together, these results argue that Gab1 and Gab2, two closely related PH-containing adapter proteins, might have distinct roles in coupling cytoplasmic-nuclear signal transduction. This is the first evidence that an intracellular molecule with a PH domain operates as a negative effector in signal relay to the regulation of gene expression.

Regulation of mRNA export by nutritional status in fission yeast

We have isolated a mutation in nup184(nup184-1) that is synthetically lethal with the mRNA export defective rae1-167 mutation in Schizosaccharomyces pombe. The consequence of the synthetic lethality is a defect in mRNA export. The predicted Nup184p is similar to Nup188p of Saccharomyces cerevisiae, and a Nup184p-GFP fusion localizes to the nuclear periphery in a punctate pattern. The Deltanup184 null mutant is viable and also is synthetically lethal with rae1-167. In a rae1(+) background, both the nup184-1 and Deltanup184 mutations confer sensitivity to growth in nutrient-rich medium (YES) that is accompanied by nuclear poly(A)+ RNA accumulation. Removal of the cAMP-dependent protein kinase, Pka1p, relieved the growth and mRNA export defects of nup184 mutants when grown in nutrient-rich medium. The activation of Pka1p is necessary, but not sufficient, to cause the severe poly(A)+ RNA export defects when nup184 mutant cells are incubated in YES, suggesting nutritional status can also regulate poly(A)+ RNA export. Our results suggest that the regulation of poly(A)+ RNA export by Pka1p kinase appears to be indirect, via a translation-dependent step, but post-translationally in response to YES.

Irreversible inhibition of epidermal growth factor receptor tyrosine kinase with in vivo activity by N-[4-[(3-bromophenyl)amino]-6-quinazolinyl]-2-butynamide (CL-387,785)

It has been shown previously that 4-anilino quinazolines compete with the ability of ATP to bind the epidermal growth factor receptor (EGF-R), inhibit EGF-stimulated autophosphorylation of tyrosine residues in EGF-R, and block EGF-mediated growth. Since millimolar concentrations of ATP in cells could reduce the efficacy of 4-anilino quinazolines in cells and the activity of these compounds would not be sustained once they were removed from the body, we reasoned that irreversible inhibitors of EGF-R might improve the activity of this series of compounds in animals. Molecular modeling of the EGF-R kinase domain was used to design irreversible inhibitors. We herein describe one such inhibitor: N-[4-[(3-bromophenyl)amino]-6-quinazolinyl]2-butynamide, known as CL-387,785. This compound covalently bound to EGF-R. It also specifically inhibited kinase activity of the protein (IC50 = 370+/-120 pM), blocked EGF-stimulated autophosphorylation of the receptor in cells (ic50 approximately 5 nM), inhibited cell proliferation (IC50 = 31-125 nM) primarily in a cytostatic manner in cell lines that overexpress EGF-R or c-erbB-2, and profoundly blocked the growth of a tumor that overexpresses EGF-R in nude mice (when given orally at 80 mg/kg/day for 10 days, daily). We conclude that CL-387,785 is useful for studying the interaction of small molecules with EGF-R and may have clinical utility.

Effects of qigong on late-stage complex regional pain syndrome

CONTEXT

Despite the growing popularity of qigong in the West, few well-controlled studies using a sham master to assess the clinical efficacy of qigong have been conducted.

OBJECTIVE

To study the effect of qigong on treatment-resistant patients with late-stage complex regional pain syndrome type I.

DESIGN

Block-random placebo-controlled clinical trial.

SETTING

Pain Management Center at New Jersey Medical School.

PATIENTS

26 adult patients (aged 18 to 65 years) with complex regional pain syndrome type I.

INTERVENTIONS

The experimental group received qi emission and qigong instruction (including home exercise) by a qigong master. The control group received a similar set of instructions by a sham master. The experimental protocol included 6 forty-minute qigong sessions over 3 weeks, with reevaluation at 6 and 10 weeks. Assessment included comprehensive medical history, physical exam, psychological evaluation, necessary diagnostic testing. Symptom Check List 90, and the Carleton University Responsiveness to Suggestion Scale.

MAIN OUTCOME MEASURES

Thermography, swelling, discoloration, muscle wasting, range of motion, pain intensity rating, medication usage, behavior assessment (activity level and domestic disability), frequency of pain awakening, mood assessment, and anxiety assessment.

RESULTS

22 subjects completed the protocol. Among the genuine qigong group, 82% reported less pain by the end of the first training session compared to 45% of control patients. By the last training session, 91% of qigong patients reported analgesia compared to 36% of control patients. Anxiety was reduced in both groups over time, but the reduction was significantly greater in the experimental group than in the control group.

CONCLUSIONS

Using a credible placebo to control for nonspecific treatment effects, qigong training was found to result in transient pain reduction and long-term anxiety reduction. The positive findings were not related to preexperimental differences between groups in hypnotizability. Future studies of qigong should control for possible confounding influences and perhaps use clinical disorders more responsive to psychological intervention.

Organization of the human myostatin gene and expression in healthy men and HIV-infected men with muscle wasting

Myostatin, a member of the transforming growth factor-beta superfamily, is a genetic determinant of skeletal muscle growth. Mice and cattle with inactivating mutations of myostatin have marked muscle hypertrophy. However, it is not known whether myostatin regulates skeletal muscle growth in adult men and whether increased myostatin expression contributes to wasting in chronic illness. We examined the hypothesis that myostatin expression correlates inversely with fat-free mass in humans and that increased expression of the myostatin gene is associated with weight loss in men with AIDS wasting syndrome. We therefore cloned the human myostatin gene and cDNA and examined the gene's expression in the skeletal muscle and serum of healthy and HIV-infected men. The myostatin gene comprises three exons and two introns, maps to chromosomal region 2q33.2, has three putative transcription initiation sites, and is transcribed as a 3.1-kb mRNA species that encodes a 375-aa precursor protein. Myostatin is expressed uniquely in the human skeletal muscle as a 26-kDa mature glycoprotein (myostatin-immunoreactive protein) and secreted into the plasma. Myostatin immunoreactivity is detectable in human skeletal muscle in both type 1 and 2 fibers. The serum and intramuscular concentrations of myostatin-immunoreactive protein are increased in HIV-infected men with weight loss compared with healthy men and correlate inversely with fat-free mass index. These data support the hypothesis that myostatin is an attenuator of skeletal muscle growth in adult men and contributes to muscle wasting in HIV-infected men.

Effects of testosterone replacement with a nongenital, transdermal system, Androderm, in human immunodeficiency virus-infected men with low testosterone levels

Although weight loss associated with human immunodeficiency virus (HIV) infection is multifactorial in its pathogenesis, it has been speculated that hypogonadism, a common occurrence in HIV disease, contributes to depletion of lean tissue and muscle dysfunction. We, therefore, examined the effects of testosterone replacement by means of Androderm, a permeation-enhanced, nongenital transdermal system, on lean body mass, body weight, muscle strength, health-related quality of life, and HIV-disease markers. We randomly assigned 41 HIV-infected, ambulatory men, 18-60 yr of age, with serum testosterone levels below 400 ng/dL, to 1 of 2 treatment groups: group I, two placebo patches (n = 21); or group II, two testosterone patches designed to release 5 mg testosterone over 24 h. Eighteen men in the placebo group and 14 men in the testosterone group completed the 12-week treatment. Serum total and free testosterone and dihydrotestosterone levels increased, and LH and FSH levels decreased in the testosterone-treated, but not in the placebo-treated, men. Lean body mass and fat-free mass, measured by dual energy x-ray absorptiometry, increased significantly in men receiving testosterone patches [change in lean body mass, +1.345 +/- 0.533 kg (P = 0.02 compared to no change); change in fat-free mass, +1.364 +/- 0.525 kg (P = 0.02 compared to no change)], but did not change in the placebo group [change in lean body mass, 0.189 +/- 0.470 kg (P = NS compared to no change); change in fat-free mass, 0.186 +/- 0.470 kg (P = NS compared to no change)]. However, there was no significant difference between the 2 treatment groups in the change in lean body mass. The change in lean body mass during treatment was moderately correlated with the increment in serum testosterone levels (r = 0.41; P = 0.02). The testosterone-treated men experienced a greater decrease in fat mass than those receiving placebo patches (P = 0.04). There was no significant change in body weight in either treatment group. Changes in overall quality of life scores did not correlate with testosterone treatment; however, in the subcategory of role limitation due to emotional problems, the men in the testosterone group improved an average of 43 points of a 0-100 possible score, whereas those in the placebo group did not change. Red cell count increased in the testosterone group (change in red cell count, +0.1 +/- 0.1 10(12)/L) but decreased in the placebo group (change in red cell count, -0.2 +/- 0.1 10(12)/L). CD4+ and CD8+ T cell counts and plasma HIV copy number did not significantly change during treatment. Serum prostate-specific antigen and plasma lipid levels did not change in either treatment group. Testosterone replacement in HIV-infected men with low testosterone levels is safe and is associated with a 1.35-kg gain in lean body mass, a significantly greater reduction in fat mass than that achieved with placebo treatment, an increased red cell count, and an improvement in role limitation due to emotional problems. Further studies are needed to assess whether testosterone supplementation can produce clinically meaningful changes in muscle function and disease outcome in HIV-infected men.

Additional possible tools for identification of proteins on one- or two-dimensional electrophoresis

Additional, essentially chemical, identification methods of proteins in polyacrylamide gel electrophoresis are described. Two cleavages of peptide bonds were used at the C-side of aspartic acid with a 0.2% pentafluoropropionic acid (PFPA) aqueous vapor at 90 degrees C for 4-16 h, and the N-side of serine/threonine with an S-ethyl trifluorothioacetate vapor at 50 degrees C for 6-24 h. The products were analyzed by mass spectrometry-peptide mass fingerprinting. A new type of C-terminal sequencing at multisites of protein was introduced. An aqueous vapor of 90% PFPA at 90 degrees C for 2-16 h provided cleavages at the C-side of aspartic acid and the N-side of serine/threonine and simultaneous successive truncation at the C-termini of the cleaved fragments. The product resulted in C-terminal sequences at multisites in proteins by mass spectrometric analysis. The following chemical deblocking methods were used. Anhydrous hydrazine vapor at -5 degrees C for 8 h deblocked the N-formyl group, and the vapor at 20 degrees C for 4 h deblocked pyrrolidone carboxylate. N-acetylserine/threonine was deblocked by aqueous vapor of 75% PFPA at 50 degrees C for 1 h, followed by reaction with p-sulfophenylisothiocyanate at pH 6.0. These methods were applied to a variety of protein spots on polyacrylamide gels. A new stepwise C-terminal sequencing of protein from polyacrylamide gels is also described.

The use of a sensitive equilibrium dialysis method for the measurement of free testosterone levels in healthy, cycling women and in human immunodeficiency virus-infected women

Measurements of total and free testosterone levels in women have lacked precision and accuracy because of limited assay sensitivity. The paucity of normative data on total and free testosterone levels in healthy women has confounded interpretation of androgen levels in women with human immunodeficiency virus (HIV) infection and other disease states. Therefore, the objectives of this study were to develop sensitive assays for the measurement of the low total and free testosterone levels in women to define the range for these hormones during the normal menstrual cycle and assess the total and free testosterone levels in HIV-infected women. By using a larger volume of serum, increasing the incubation time, and reducing the antibody concentration, the sensitivity of the total testosterone assay was increased to 0.008 nmol/L, and that of the free testosterone assay was increased to 2 pmol/L. The mean percent free testosterone was 1.0 +/- 0.1% of the total testosterone. Serum total and free testosterone levels in the follicular and luteal phases were not significantly different, but both demonstrated a modest preovulatory increase, 3 days before the LH peak. Serum total [0.50 +/- 0.32 (14.60 +/- 9.22) vs. 1.2 +/- 0.7 nmol/L (34.3 +/- 21.0 ng/dL); P < 0.0001] and free testosterone levels (5.56 +/- 2.70 (1.58 +/- 0.80) vs. 12.8 +/- 5.5 pmol/L (3.4 +/- 1.7 pg/mL); P < 0.0001) were significantly lower in HIV-infected women (n = 37) than in healthy women (n = 34). Serum total and free testosterone levels were also significantly lower in HIV-infected women who were menstruating normally. There were no significant differences in serum total and free testosterone levels between those who had lost weight and those who had not. Testosterone levels correlated inversely with plasma HIV ribonucleic acid copy number. Serum FSH, but not LH, levels were significantly higher in HIV-infected women than in controls. Using assays with sufficient sensitivity, we defined the range for total and free testosterone levels during the normal menstrual cycle. Serum total and free testosterone levels are lower in HIV-infected women and correlate inversely with plasma HIV ribonucleic acid levels. The hypothesis that androgen deficiency contributes to wasting in HIV-infected women remains to be tested.

A randomised placebo controlled trial of suppressive acyclovir in late pregnancy in women with recurrent genital herpes infection

OBJECTIVE

To evaluate the efficacy and safety of a suppressive course of acyclovir in late pregnancy in women with recurrent genital herpes infection on the incidence of viral shedding, herpes lesion development and caesarean section for recurrent genital herpes.

DESIGN

Double-blind, randomised placebo controlled clinical trial.

SETTING

A department of genitourinary medicine in Sheffield and an antenatal clinic in London.

POPULATION

Pregnant women with recurrent genital herpes infection at < 36 weeks of gestation.

METHODS

Participating women were given acyclovir 200 mg four times a day (or matching placebo) from 36 weeks of gestation until the time of delivery. Women were seen weekly and viral cultures were obtained from the cervix and vulva. Decisions regarding mode of delivery were left to the discretion of the attending obstetrician.

MAIN OUTCOME MEASURES

Delivery by caesarean section for recurrent genital herpes infection. Number of episodes of recurrent genital herpes infection and number of episodes of asymptomatic viral shedding during the treatment period. In addition blood was taken at two weekly intervals to determine acyclovir levels.

RESULTS

The total number of women recruited was 63 (31 received acyclovir and 32 received placebo). The number of women undergoing delivery by caesarean section for recurrent herpes at the time of delivery was 12 (19%). The odds ratio for delivery by caesarean section in women taking acyclovir, compared with those taking placebo, was 0.44 (95% CI 0.09-1.59). The odds ratio for clinical recurrences during treatment was 0.10 (95% confidence interval 0.00-0.86) and the odds ratio for clinical recurrence or asymptomatic shedding during treatment was 0.32 (95% CI 0.05-1.56).

CONCLUSION

This trial was unable to demonstrate that acyclovir can significantly decrease the number of caesarean section deliveries; however, the number of clinical recurrences was significantly reduced. Two episodes of asymptomatic virus shedding both occurred in women taking acyclovir. At the present time there is little evidence to suggest that acyclovir should be used outside randomised controlled trials for the suppression of recurrent genital herpes infection during pregnancy.

[The biodegradation of trichloroethylene by a methanotrophic bacterium]

A Methylomonas (strain GYJ3) isolated in our laboratory was identified as the type II methanotroph on the basis of the intractytoplasmic membrane of the ultrastructure. The optimal culture conditions for production of the soluble from of methane monooxygenase (MMO) were determined, in which the ratio of methane to air in atmosphere was 2 to 1 and Cu2+ concentration was 1.5 mumol/L. The biodegradation of trichoroethylene(TCE) by the resting cells of the strain GYJ3 was studied. All experiments were performed with cells grown under above conditions and thus expressing soluble MMO. This results showed that TCE at the high concentration of 30 mg/L did not inhibit to the enzymes in the cells. Addition of formate increased the initial specific TCE degradation rates. The product of TCE oxidation was found to be toxic to the cells. The degree of inactivation of MMO was proportional to the amount of TCE degraded. The TCE degradation capacities(Tc) of resting cells was determined. In no-formate and formate-fed experiments, the TCE degradation capacities were found to be 0.0778 and 0.0851 mg of TCE/mg of dry cell, respectively.

Transforming growth factor-beta1 (TGF-beta1) in penile and prostate growth in the rat during sexual maturation

The goal of this study was to determine whether transforming growth factor-beta1 (TGF-beta1) may contribute to the arrest of penile growth and the down-regulation of androgen receptors (AR) that occur during sexual maturation in the rat penis. For this purpose, body, penis, and prostate weights were obtained from male rats of increasing ages, and penis and prostate TGF-beta1 concentrations were determined by a sandwich enzyme-linked immunosorbent assay. The cytosol fraction was obtained from the shafts and glandes of immature (19-day-old) and adult (90-day-old) rat penises, and ARs were measured by a western blot assay. The effect of exogenous TGF-beta1 on penile growth was examined in vivo in two groups of immature rats (21 and 27 days old) implanted with miniosmotic pumps delivering either human TGF-beta1 or vehicle only directly into the corpora cavernosa for 6 days. The penises, prostates, and testes were weighed, and the AR content was estimated by western blot. The growth rate of the penis declined after 8 weeks of age, whereas the ventral prostate growth rate increased until 14 weeks of age and then slowed down. The content of penile AR protein decreased seven-fold in the adult rats compared to the immature animals. Penile TGF-beta1 concentration increased nearly three-fold from the 19-day-old rats to a peak at 60 days of age and then decreased over the next 4 months to the initial levels. In contrast, TGF-beta1 concentration in the prostate was not significantly affected by age and remained below the lowest penile values in all age groups. Transforming growth factor-beta1 given locally to the penis reduced penile shaft weight by 38 and 22% in two groups of immature rats, while the weights of the penile glans, testis, and ventral prostate remained unaffected. Androgen receptor content was higher in the glans than in the shaft and was not changed by TGF-beta1 treatment. These results suggest that the increase of TGF-beta1 levels in the penis may reinforce growth arrest caused by the down-regulation of penile ARs, whereas the maintenance of a high content of ARs and a low TGF-beta1 concentration may allow prostate growth to continue.

Npp106p, a Schizosaccharomyces pombe nucleoporin similar to Saccharomyces cerevisiae Nic96p, functionally interacts with Rae1p in mRNA export

To identify components of the mRNA export machinery in Schizosaccharomyces pombe, a screen was developed to identify mutations that were synthetically lethal with the conditional mRNA export allele rae1-167. Mutations defining three complementation groups were isolated, and here we report the characterization of npp106 (for nuclear pore protein of 106 kDa). This gene encodes a predicted protein that has significant similarity to the Nic96p nucleoporin of Saccharomyces cerevisiae. Consistent with Npp106p being a nucleoporin, a functional green fluorescent protein (GFP)-tagged Npp106p localized to the nuclear periphery. In contrast to NIC96, the npp106 gene is not essential. Moreover, a delta npp106 mutant did not show cytoplasmic mislocalization of a simian virus 40 nuclear localization signal-GFP-LacZ reporter protein, and a fraction of cells had accumulation of poly(A)+ RNA in the nucleus. A consequence of the synthetic lethality between rae1-167 and npp106-1 was the accumulation of poly(A)+ RNA in the nucleus when cells were grown under synthetic lethal conditions. In addition to npp106-1, which is a nonsense mutation that truncates the protein at amino acid 292, the delta npp106 mutation was synthetically lethal with rae1-167, suggesting that the synthetic lethality is a consequence of the loss of a function of npp106. We further demonstrate that a region between amino acids 74 and 348 of Npp106p is required for complementation of the synthetic lethality. These results uncover a potential direct or indirect involvement of Npp106p in mRNA export.

Direct evidence for a soluble methane monooxygenase from type I methanotrophic bacteria: purification and properties of a soluble methane monooxygenase from Methylomonas sp. GYJ3

The hydroxylase and reductase components of a soluble methane monooxygenase from type I methanotrophs--Methylomonas sp. GYJ3--were purified by a multiple-step LC procedure. The hydroxylase (approximately 240 kDa, determined by an HPLC-size exclusion chromatography method) has three subunits with molecular masses of 56, 43, and 27 kDa, suggesting that the enzyme has an (alphabeta gamma)2 subunit structure. The HPLC method was developed to purify the hydroxylase component, and the purified protein has a specific activity of 541 nmol propene oxide x mg(-1) protein x min(-1), which is two times the specific activity of the protein purified by the two-step LC procedure. The iron content in the hydroxylase purified by the two-step LC procedure is 2.1 mol of Fe per mole of protein, but the iron content in the protein by the HPLC procedure is 3.78 mol of Fe per mole of protein. The diversity of iron contents in this protein is due mainly to the use of different purification methods. The reductase has a molecular mass of 42 kDa. The UV-VIS spectrum of the protein is similar to that of proteins from other methanotrophs, suggesting that the protein contains a FAD cofactor and a [2Fe-2S] center. The partially purified component B stimulated the MMO activity of the hydroxylase and reductase system by 40-fold.

Complementary deoxyribonucleic acid cloning and characterization of a putative human axonemal dynein light chain gene

Immotile Cilia Syndrome (ICS) is characterized by recurrent sinus and lung infections, bronchiectasis, and sperm immotility. Nasal cilia and sperm tails in patients with ICS exhibit a variety of ultrastructural defects, often including shortening or absence of the inner dynein arms. Immotile mutant strains of Chlamydomonas, a biflagellated algae, have ultrastructural defects similar to those seen in patients with this clinical disorder. Furthermore, splice-site mutations in the Chlamydomonas inner dynein arm gene (p28) are associated with impaired flagellar motility. We therefore hypothesized that the human homologue of the Clamydomonas dynein p28 gene would be an attractive candidate gene for patients with ICS. Accordingly, we cloned the full length complementary DNA (cDNA) and genomic clone by screening of appropriate libraries and databases, using the protein sequence of the Chlamydomonas p28 gene. The human homologue is encoded by a 921 bp transcript (accession no. AF006386) with an open reading frame of 257 amino acids. Using somatic cell and radiation hybrid panels, the hp28 gene was mapped to human chromosome 1p35.1. The hp28 cDNA probe hybridizes to sequences in all species on a zoo blot containing genomic DNA from yeast to human. Northern blot analysis reveals two hp28 gene transcripts, 0.9 and 2.5 kb, in many tissues. The 0.9 kb transcript is expressed at a 20-fold higher level than the 2.5-kb transcript in the testis. The entire gene is included in a 20-kb EcoRI genomic fragment and has 7 exons and 6 introns. Cloning of the hp28 cDNA and mapping of the intron-exon junctions should now make it possible to test whether a subset of ICS is a consequence of mutations in the human axonemal dynein light chain gene hp28.

A deletion mutation in the SH2-N domain of Shp-2 severely suppresses hematopoietic cell development

Shp-1 and Shp-2 are cytoplasmic protein tyrosine phosphatases that contain two Src homology 2 (SH2) domains. A negative regulatory role of Shp-1 in hematopoiesis has been strongly implicated by the phenotype of motheaten mice with a mutation in the Shp-1 locus, which is characterized by leukocyte hypersensitivity, deregulated mast cell function, and excessive erythropoiesis. A targeted deletion of 65 amino acids in the N-terminal SH2 (SH2-N) domain of Shp-2 leads to an embryonic lethality at midgestation in homozygous mutant mice. To further dissect the Shp-2 function in hematopoietic development, we have isolated homozygous Shp-2 mutant embryonic stem (ES) cells. Significantly reduced hematopoietic activity was observed when the mutant ES cells were allowed to differentiate into embryoid bodies (EBs), compared to the wild-type and heterozygous ES cells. Further analysis of ES cell differentiation in vitro showed that mutation in the Shp-2 locus severely suppressed the development of primitive and definitive erythroid progenitors and completely blocked the production of progenitor cells for granulocytes-macrophages and mast cells. Reverse transcriptase PCR analysis of the mutant EBs revealed reduced expression of several specific marker genes that are induced during blood cell differentiation. Stem cell factor induction of mitogen-activated protein kinase activity was also blocked in Shp-2 mutant cells. Taken together, these results indicate that Shp-2 is an essential component and primarily plays a positive role in signaling pathways that mediate hematopoiesis in mammals. Furthermore, stimulation of its catalytic activity is not sufficient, while interaction via the SH2 domains with the targets or regulators is necessary for its biological functions in cells. The in vitro ES cell differentiation assay can be used as a biological tool in dissecting cytoplasmic signaling pathways.

Abnormal mesoderm patterning in mouse embryos mutant for the SH2 tyrosine phosphatase Shp-2

Shp-1, Shp-2 and corkscrew comprise a small family of cytoplasmic tyrosine phosphatases that possess two tandem SH2 domains. To investigate the biological functions of Shp-2, a targeted mutation has been introduced into the murine Shp-2 gene, which results in an internal deletion of residues 46-110 in the N-terminal SH2 domain. Shp-2 is required for embryonic development, as mice homozygous for the mutant allele die in utero at mid-gestation. The Shp-2 mutant embryos fail to gastrulate properly as evidenced by defects in the node, notochord and posterior elongation. Biochemical analysis of mutant cells indicates that Shp-2 can function as either a positive or negative regulator of MAP kinase activation, depending on the specific receptor pathway stimulated. In particular, Shp-2 is required for full and sustained activation of the MAP kinase pathway following stimulation with fibroblast growth factor (FGF), raising the possibility that the phenotype of Shp-2 mutant embryos results from a defect in FGF-receptor signalling. Thus, Shp-2 modulates tyrosine kinase signalling in vivo and is crucial for gastrulation during mammalian development.

[High-malar plasty through an intraoral approach]

Request for high-malar plasty, a purely aesthetic surgery, is fairly common in the Oriental. For an optimal result, consideration should be given to integrating the malar reconstruction with the facial features. A new method for correction of the high-malar deformity was introduced, in which the intraoral approach through an L-shaped incision and osteotomy were employed. The technique is simple, safe and can be done with local anesthesia on an outpatient basis. From December 1994 to February 1996, we have successfully treated 25 cases with this method. Postoperative follow-up for 6 months to 1 year revealed aesthetically satisfactory results. Complications are minor, including swelling, ecchymosis, etc. We conclude that high-malar plasty through the intraoral approach is a safe, effective and relatively simple technique for mild and moderate high-malar deformity.

[Study on transposition behavior of IS5376 in Bacillus stearothermophilus]

IS5376 and IS5377 are two transposable elements discovered in Bacillus stearothermophilus. Analysis of random samples revealed that the frequency of transposition of IS5376 from CU21 chromosome to plasmids pFDC5 and pFDC12 was much higher at 65 degrees C than that at 48 degrees C while that of IS5377 was very low at both 48 degrees C and 65 degrees C. The exact nature of the temperature effect is obscure at present from evidences obtained so far it is concluded that this is a consequence of the innate property of IS5376. Furthermore, it was found that a certain degree of site specificity in transposition was evident and that a direct repeat of 4 or 5 bp of the target DNA appeared at the site of transposition.

Molecular characterization of specific interactions between SHP-2 phosphatase and JAK tyrosine kinases

Interactions between SHP-2 phosphotyrosine phosphatase and JAK tyrosine kinases have recently been implicated in cytokine signal transduction. However, the molecular basis of these interactions is not well understood. In this study, we demonstrate that SHP-2 is tyrosine-phosphorylated by and associated with JAK1 and JAK2 but not JAK3 in COS-1 cell cotransfection experiments. SHP-2 phosphatase activity appears not to be required for JAK and SHP-2 interactions because SHP-2 with a mutation at amino acid 463 from Cys to Ser, which renders SHP-2 inactive, can still bind JAKs. We further demonstrate that SHP-2 SH2 domains (amino acids 1-209) are not essential for the association of JAKs with SHP-2, and the region between amino acids 232 and 272 in SHP-2 is important for the interactions. Furthermore, tyrosine residues 304 and 327 in SHP-2 are phosphorylated by JAKs, and phosphorylated SHP-2 can associate with the downstream adapter protein Grb2. Finally, deletion of the N terminus but not the kinase-like domain of JAK2 abolishes the association of JAK2 with SHP-2. Taken together, these studies identified novel sequences for SHP-2 and JAK interactions that suggest unique signaling mechanisms mediated by these two molecules.

6-Hydroxycatecholine, a choline-mimicking analogue of the selective neurotoxin, 6-hydroxydopamine

The synthesis and properties of 6-hydroxy-N,N-dimethylepinephrine (6-hydroxy-catecholine) are reported. This agent is intended for use as a selective presynaptic cholinotoxin and is based on previously reported neurotoxins of the same type. 6-hydroxycatecholine is a close structural analogue of the catecholaminergic neurotoxin 6-hydroxydopamine, and is expected both to be selectively reactive at cholinergic sites and to undergo less vigorous and potentially more selective inactivating reactions. It is also possible that in specific dementia-inducing pathologies, 6-hydroxycatecholine could be formed endogenously.

Surface-epitope masking and expression cloning identifies the human prostate carcinoma tumor antigen gene PCTA-1 a member of the galectin gene family

The selective production of monoclonal antibodies (mAbs) reacting with defined cell surface-expressed molecules is now readily accomplished with an immunological subtraction approach, surface-epitope masking (SEM). Using SEM, prostate carcinoma (Pro 1.5) mAbs have been developed that react with tumor-associated antigens expressed on human prostate cancer cell lines and patient-derived carcinomas. Screening a human LNCaP prostate cancer cDNA expression library with the Pro 1.5 mAb identifies a gene, prostate carcinoma tumor antigen-1 (PCTA-1). PCTA-1 encodes a secreted protein of approximately 35 kDa that shares approximately 40% sequence homology with the N-amino terminal region of members of the S-type galactose-binding lectin (galectin) gene family. Specific galectins are found on the surface of human and marine neoplastic cells and have been implicated in tumorigenesis and metastasis. Primer pairs within the 3' untranslated region of PCTA-1 and reverse transcription-PCR demonstrate selective expression of PCTA-1 by prostate carcinomas versus normal prostate and benign prostatic hypertrophy. These findings document the use of the SEM procedure for generating mAbs reacting with tumor-associated antigens expressed on human prostate cancers. The SEM-derived mAbs have been used for expression cloning the gene encoding this human tumor antigen. The approaches described in this paper, SEM combined with expression cloning, should prove of wide utility for developing immunological reagents specific for and identifying genes relevant to human cancer.

Androgens are not major down-regulators of androgen receptor levels during growth of the immature rat penis

This study was undertaken to investigate the prevalent hypothesis that androgens are responsible for the organ-specific down-regulation of penile androgen receptors (ARs) and decline of penile growth in the rat during sexual maturation. Sexually immature male rats (21 days old) were castrated and treated for 3 days ("short-term"), with high doses of: (a) testosterone and the alpha-reductase inhibitor finasteride (T/F); (b) dihydrotestosterone (DHT); or (c) finasteride alone (F). Intact and castrate controls received vehicle only. PolyA + RNA was analysed by Northern blot hybridization and ARs were estimated in the penis and ventral prostates by (3-H)R-1881 binding in the cytosol. Short-term castration, with or without F, increased penile AR mRNA, whereas high doses of T/F and DHT reduced it considerably. Although penile cytosol AR concentration in the control castrates, with or without F, paralleled the AR mRNA rise, treatment with androgens left cytosol AR content per organ and AR concentration above those of the intact rat penis despite the drop in AR mRNA. A "long-term" treatment (10 days) on 19-day-old rats with either medium or high doses of T/F and DHT also failed to down-regulate penile cytosol ARs below the intact controls. Western blot analysis of penile cytosol AR levels confirmed these results. Block of pituitary FSH and LH release by a GnRH antagonist in castrates receiving T/F or DHT at high doses did not modify the response. In the case of intact rats, high doses of T/F or DHT actually increased penile cytosol AR content. No difference was observed between T/F and DHT effects. In contrast to what occurs during sexual maturation, the prostate ARs and growth rate responded to all treatments in a similar way to what was observed in the penis. Our results suggest that increases in serum T or DHT are not major factors in the physiological down-regulation of ARs and androgen-dependent growth in the rat corpora cavernosa.

Lability of N-alkylated peptides towards TFA cleavage

Trifluoroacetic acid (TFA) is a common reagent in both solid-phase and solution peptide synthesis. It is used for the deprotection and/or cleavage of the synthesized peptide from the resin. The use of TFA under these standardized conditions is thought to be sufficiently mild, thereby preventing degradation of the desired product. However, peptides of the general structure R1-(N-alkyl X1)-X2-R2 are hydrolyzed by standard TFA solid-phase peptide synthesis (SPPS) cleavage/deprotection conditions providing fragments R1-(N-alkyl X1)-OH and H-X2-R2. The fragmentation is observed during a TFA cleavage both from the resin and in solution. The hydrolysis is proposed to proceed via an oxazolone-like intermediate in which equilibration of the chiral center of the N-alkylated residue occurs. This mechanism is supported by H/D exchange as observed MS and NMR in conjunction with HPLC.

[Detection of intrauterine transmission of human cytomegalovirus by nested polymerase chain reaction]

OBJECTIVE

Using nested polymerase chain reaction (PCR) to detect Intrauterine transmission of human cytomegalovirus (HCMV).

METHODS

Ninety one cases of pregnant women were devided into three groups according to their gestational stages. In the first and second trimesters, they terminated pregnancy voluntarily. HCMV-DNA in maternal and cord blood as well as placenta were detected respectively by nested PCR.

RESULTS

In the first trimester, 20 out of 30 cases were infected, Intrauterine transmission occured in 8 of the 20 infected mothers (HCMV-DNA were found in the chorionic villus). In the second trimester, 21 out of 30 cases were infected, 7 of them transmitted HCMV to their fetus through placenta. In this term, the placenta infection rate is 40% (12/30). In the third trimester, 23 out of 31 cases women infected HCMV, 18 of them transmitted HCMV to their fetus through placenta, the placenta infection rate is 66.67% (20/30). The congenital infection rate is 58.06% (18/31), much higher than the reported levels marked by cord sera IgM and (or) infants viremia.

CONCLUSIONS

HCMV transmitted from mother to infant mainly through placenta. Nested PCR provides a valuable method that can detected virus infection not limited by virus reproduction state and human immuno-reaction ability.

Identification of the human prostatic carcinoma oncogene PTI-1 by rapid expression cloning and differential RNA display

Elucidating the relevant genomic changes mediating development and evolution of prostate cancer is paramount for effective diagnosis and therapy. A putative dominant-acting nude mouse prostatic carcinoma tumor-inducing gene, PTI-1, has been cloned that is expressed in patient-derived human prostatic carcinomas but not in benign prostatic hypertrophy or normal prostate tissue. PTI-1 was detected by cotransfecting human prostate carcinoma DNA into CREF-Trans 6 cells, inducing tumors in nude mice, and isolating genes displaying increased expression in tumor-derived cells by using differential RNA display (DD). Screening a human prostatic carcinoma (LNCaP) cDNA library with a 214-bp DNA fragment found by DD permitted the cloning of a full-length 2.0-kb PTI-1 cDNA. Sequence analysis indicates that PTI-1 is a gene containing a 630-bp 5' sequence and a 3' sequence homologous to a truncated and mutated form of human elongation factor 1 alpha. In vitro translation demonstrates that the PTI-1 cDNA encodes a predominant approximately 46-kDa protein. Probing Northern blots with a DNA fragment corresponding to the 5' region of PTI-1 identifies multiple PTI-1 transcripts in RNAs from human carcinoma cell lines derived from the prostate, lung, breast, and colon. In contrast, PTI-1 RNA is not detected in human melanoma, neuroblastoma, osteosarcoma, normal cerebellum, or glioblastoma multiforme cell lines. By using a pair of primers recognizing a 280-bp region within the 630-bp 5' PTI-1 sequence, reverse transcription-PCR detects PTI-1 expression in patient-derived prostate carcinomas but not in normal prostate or benign hypertrophic prostate tissue. In contrast, reverse transcription-PCR detects prostate-specific antigen expression in all of the prostate tissues. These results indicate that PTI-1 may be a member of a class of oncogenes that could affect protein translation and contribute to carcinoma development in human prostate and other tissues. The approaches used, rapid expression cloning with the CREF-Trans 6 system and the DD strategy, should prove widely applicable for identifying and cloning additional human oncogenes.

Fractal dimension of exon and intron sequences

In this paper, the concept of fractal is applied to describe the features of nucleotide sequences. We introduce the mapping from nucleotide sequences to two-dimensional metric space. Then we use this mapping to study quantitatively the self-similarity of exon and intron sequences in different scales. We find that self-similarity exists in the geometrical range and main range of a nucleotide sequence and define the fractal dimension in these ranges. The results show that the fractal properties of exon sequences are quite different from those of introns, reflecting their difference in structure and function. The fractal dimension of the geometrical range may be used to predict the exon regions of a raw nucleotide sequence.

Involvement of SH2-containing phosphotyrosine phosphatase Syp in erythropoietin receptor signal transduction pathways

Erythropoietin (Epo) regulates the proliferation and differentiation of erythroid precursors. The phosphorylation of proteins at tyrosine residues is critical in the growth signaling induced by Epo. This mechanism is regulated by the activities of both protein-tyrosine kinases and protein tyrosine phosphatases. The discovery of phosphotyrosine phosphatases that contain SH2 domains suggests roles for these molecules in growth factor signaling pathways. We found that Syp, a phosphotyrosine phosphatase, widely expressed in all tissues in mammals became phosphorylated on tyrosine after stimulation with Epo in M07ER cells engineered to express high levels of human EpoR. Syp was complexed with Grb2 in Epo-stimulated M07ER cells. Direct binding between Syp and Grb2 was also observed in vitro. Furthermore, Syp appeared to bind directly to tyrosine-phosphorylated EpoR in M07ER cells. Both NH2-terminal and COOH-terminal SH2 domains of Syp, made as glutathione S-transferase fusion proteins, were able to bind to the tyrosine-phosphorylated EpoR in vitro. These results suggest that Syp may be an important signaling component downstream of the EpoR and may regulate the proliferation and differentiation of hematopoietic cells.