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Biomedical subjects

S Pang

Publications and source records attributed to S Pang.

At least 37 records · Page 2Linked to original sources
PubMed2000

SULT1A1 catalyzes 2-methoxyestradiol sulfonation in MCF-7 breast cancer cells.

In a previous study of nine human breast-derived cell lines, rates of metabolism of 17beta-estradiol (E(2)) were greatly enhanced when cultures were exposed to the aromatic hydrocarbon receptor agonist, 2,3,7,8-tetrachlorodibenzo-p-dioxin. Elevated rates of E(2) hydroxylation at the C-2, -4, -6alpha and -15alpha positions were observed concomitant with the induction of cytochromes P450 1A1 and 1B1. In each cell line, 2- and 4-hydroxyestradiol (2- and 4-OHE(2)) were converted to 2- and 4-methoxyestradiol (2- and 4-MeOE(2)) by the action of catechol O:-methyltransferase. In this study, conjugation of these estrogen metabolites was investigated. A comparison of the levels of metabolites determined with and without prior treatment of the media with a crude beta-glucuronidase/sulfatase preparation showed that most of the 2-MeOE(2) present was in conjugated form, whereas 4-MeOE(2), 6alpha-OHE(2) and 15alpha-OHE(2) were minimally conjugated. Inhibitor studies suggested that it was the sulfatase activity of the preparation that hydrolyzed the 2-MeOE(2) conjugates in MCF-7 cell media; the presence of 2-MeOE(2)-3-sulfate in MCF-7 culture media was confirmed by electrospray ion-trap mass spectrometry. To identify the enzyme catalyzing this conjugation, the expression of mRNAs encoding five sulfotransferases (SULT1A1, SULT1A2, SULT1A3, SULT1E1 and SULT2A1) was evaluated in the nine cell lines by use of the reverse transcription-polymerase chain reaction. Only expression of SULT1A1 mRNA correlated with the observed conjugation of nanomolar levels of 2-MeOE(2) in these cell lines. Cloning and sequencing of SULT1A1 cDNA from MCF-7 cells revealed that mRNAs encoding two previously identified allelic variants, SULT1A1*1 ((213)Arg) and SULT1A1*2 ((213)His), were expressed in these cells. Heterologous cDNA-directed expression of either variant in MDA-MB-231 cells, which do not normally express SULT1A1, conferred 2-MeOE(2) sulfonation activity. The SULT1A1 allelic variants were also expressed in SF:9 insect cells, from which post-microsomal supernatants were used to determine K:(m) values of 0.90 +/- 0.12 and 0.81 +/- 0.06 microM for SULT1A1*1 and SULT1A1*2, respectively, with 2-MeOE(2) as substrate. These results show that SULT1A1 is an efficient and selective catalyst of 2-MeOE(2) sulfonation and, as such, may be important in modulating the anticarcinogenic effects of 2-MeOE(2) that have been described recently.

2-Methoxyestradiol↗
PubMed2000

Human immunodeficiency virus Env-independent infection of human CD4(-) cells.

CD4(-) epithelial cells covering mucosal surfaces serve as the primary barrier to prevent human immunodeficiency virus type 1 (HIV-1) infection. We used HIV-1 vectors carrying the enhanced green fluorescent protein gene as a reporter gene to demonstrate that HIV-1 can infect some CD4(-) human epithelial cell lines with low but significant efficiencies. Importantly, HIV-1 infection of these cell lines is independent of HIV-1 envelope proteins. The Env-independent infection of CD4(-) cells by HIV-1 suggests an alternative pathway for HIV-1 transmission. Even on virions bearing Env, a neutralizing antibody directed against gp120 is incapable of neutralizing the infection of these cells, thus raising potential implications for HIV-1 vaccine development.

CD4 Antigens↗
PubMed2000

Characterization of two novel homozygous missense mutations involving codon 6 and 259 of type II 3beta-hydroxysteroid dehydrogenase (3betaHSD) gene causing, respectively, nonsalt-wasting and salt-wasting 3betaHSD deficiency disorder.

We identified two homozygous missense mutations in the human type II 3beta-hydroxysteroid dehydrogenase (3/betaHSD) gene, the first in codon 6 of exon II [CTT (Leu) to TTT (Phe)] in a male infant with hyperpigmented scrotum and hypospadias, raised as a male and no apparent salt-wasting since neonatal age, and the second in codon 259 of exon IV [ACG (Thr) to ATG (Met)] in a male pseudohermaphrodite with labial scrotal folds, microphallus, chordee, and fourth degree hypospadias, raised as a female and with salt-wasting disorder since neonatal age. In vitro transient expression of mutant type II 3betaHSD complementary DNAs of L6F, T259M, as well as T259R for comparison was examined by a site-directed mutagenesis and transfection of construct into COS-1 and COS-7 cells. Northern blot analysis revealed expression of similar amounts of type II 3betaHSD messenger ribonucleic acid from the COS-1 cells transfected by L6F, T259M, T259R, and wild-type (WT) complementary DNAs. Western immunoblot analysis revealed a similar amount of L6F mutant protein compared to WT enzyme from COS-1 cells, but neither L6F from COS-7 cells nor T259M or T259R mutant protein in COS-1 or COS-7 cells was detectable. Enzyme activity in intact COS-1 cells using 1 micromol/L pregnenolone as substrate in the medium after 6 h revealed relative conversion rates of pregnenolone to progesterone of 46% by WT enzyme, 22% by L6F enzyme, and 8% by T259M enzyme and less than 4% activity by T259R enzyme. Using 1 micromol/L dehydroepiandrosterone as substrate, the relative conversion rate of dehydroepiandrosterone to androstenedione after 6 was 89% by WT enzyme, 35% by L6F enzyme, 5.1% by T259M enzyme and no activity by T259R enzyme. However, the L6F mutant 3betaHSD activity, despite its demonstration in the intact cells, was not detected in homogenates of COS-1 cells or in immunoblots of COS-7 cells, suggestive of the relatively unstable nature of this protein in vitro, possibly attributable to the decreased 3betaHSD activity. In the case of T259M and T259R mutations, consistently undetectable proteins in both COS cells despite detectable messenger ribonucleic acids indicate severely labile proteins resulting in either no or very little enzyme activity, and these data further substantiate the deleterious effect of a structural change in this predicted putative steroid-binding domain of the gene. In conclusion, the findings of the in vitro study of mutant type II 3betaHSD enzyme activities correlated with a less severe clinical phenotype of nonsalt-wasting and a lesser degree of genital ambiguity in the patient with homozygous L6F mutation compared to a more severe clinical phenotype of salt-wasting and severe degree of genital ambiguity in the patient with homozygous T259M mutation in the gene.

3-Hydroxysteroid Dehydrogenases↗
PubMed1999

Inductive and inhibitory effects of non-ortho-substituted polychlorinated biphenyls on estrogen metabolism and human cytochromes P450 1A1 and 1B1.

The effects of a series of non-ortho-substituted polychlorinated biphenyls (PCBs) on human cytochrome P450 1A1 (CYP1A1), a 17beta-estradiol (E2) 2-hydroxylase, and P450 1B1 (CYP1B1), an E2 4-hydroxylase, were investigated in HepG2 and MCF-7 cells. Elevated rates of 2- and 4-methoxyestradiol (2- and 4-MeOE2) formation in PCB-treated cultures were measured as activities of CYP1A1 and CYP1B1, respectively. Of the congeners investigated, 3,4,4',5-tetrachlorobiphenyl (PCB 81), 3,3',4,4',5-pentachlorobiphenyl (PCB 126), and 3,4',5-trichlorobiphenyl (PCB 39) caused marked stimulation of E2 metabolism in both cell lines. Northern blot analyses confirmed that exposure of MCF-7 cells to PCBs 81, 126, and 39 caused highly elevated levels of the CYP1A1 and CYP1B1 mRNAs. Exposure of MCF-7 cells to 3,3',4,4',5,5'-hexachlorobiphenyl (PCB 169) resulted in elevated levels of the CYP1A1 and CYP1B1 mRNAs, but did not cause elevated rates of E2 metabolism; rather, 4-MeOE2 production was depressed to below control levels in PCB 169-treated cultures. PCB 169 also inhibited the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced 4-MeOE2 and, to a lesser extent, 2-MeOE2 production in MCF-7 cells, as did PCB 126 and several other congeners. In microsomal assays, inhibition of cDNA-expressed human CYP1B1 by PCBs 169 and 126 was demonstrated. These studies with one subgroup of PCBs, the non-ortho-substituted congeners, underscore the complexity and diversity of effects of PCBs, as individual congeners were found both to induce expression and to inhibit activity of human CYP1B1 and CYP1A1.

Aryl Hydrocarbon Hydroxylases↗
PubMed1999

The natriuretic peptide clearance receptor locally modulates the physiological effects of the natriuretic peptide system.

Natriuretic peptides (NPs), mainly produced in heart [atrial (ANP) and B-type (BNP)], brain (CNP), and kidney (urodilatin), decrease blood pressure and increase salt excretion. These functions are mediated by natriuretic peptide receptors A and B (NPRA and NPRB) having cytoplasmic guanylyl cyclase domains that are stimulated when the receptors bind ligand. A more abundantly expressed receptor (NPRC or C-type) has a short cytoplasmic domain without guanylyl cyclase activity. NPRC is thought to act as a clearance receptor, although it may have additional functions. To test how NPRC affects the cardiovascular and renal systems, we inactivated its gene (Npr3) in mice by homologous recombination. The half life of [125I]ANP in the circulation of homozygotes lacking NPRC is two-thirds longer than in the wild type, although plasma levels of ANP and BNP in heterozygotes and homozygotes are close to the wild type. Heterozygotes and homozygotes have a progressively reduced ability to concentrate urine, exhibit mild diuresis, and tend to be blood volume depleted. Blood pressure in the homozygotes is 8 mmHg (1 mmHg = 133 Pa) below normal. These results are consistent with the sole cardiovascular/renal function of NPRC being to clear natriuretic peptides, thereby modulating local effects of the natriuretic peptide system. Unexpectedly, Npr3 -/- homozygotes have skeletal deformities associated with a considerable increase in bone turnover. The phenotype is consistent with the bone function of NPRC being to clear locally synthesized CNP and modulate its effects. We conclude that NPRC modulates the availability of the natriuretic peptides at their target organs, thereby allowing the activity of the natriuretic peptide system to be tailored to specific local needs.

Animals↗
PubMed1999

Caring attributes, professional self concept and technological influences in a sample of Registered Nurses in eleven countries.

Caring, the theoretical foundation of nursing, is identified as one of the core values by Hospital Authorities world-wide to be actualised in clinical practice. Exactly how caring attributes relate to nurses' professional self image and quality nursing service in the context of a contemporary technological environment have yet to be operationalised. In total, 1957 Registered Nurses from 11 different countries were involved in the study which aimed to: develop an understanding of and compare the responses to items relating to caring, professional self concept and technological influences. To collect data an instrument containing 104 Likert items was administered to RNs working in general hospitals. The instrument contained sections which examined professional self concept, technological influences and caring attributes. Descriptive and inferential statistics revealed that many of the Asian nurses in the sample were younger, had less experience yet were more qualified than their 'western' colleagues. The mean scores for the caring attributes for nurses from the Philippines, Sweden and South Africa were significantly higher than those from China (Beijing), Korea, China (Hong Kong) and Scotland. The Korean sample demonstrated the lowest mean score for professional self concept while the New Zealand sample the highest. The Australian, Canadian, NZ, Scotland and Swedish samples were strongly of the opinion that the increase in technology has not brought about the any more spare time in nursing and generally had a more negative opinion about the influence of technology when compared to those from China (Beijing), Philippines, China (Hong Kong) and Singapore. The results are discussed in the light of the cultural differences in the sample and recommendations for future research are considered.

Adult↗
PubMed1999

Clinical and functional effects of mutations in the DAX-1 gene in patients with adrenal hypoplasia congenita.

Adrenal hypoplasia congenita (AHC) is an X-linked disorder caused by mutations in a gene referred to as DAX-1. AHC is characterized by adrenal insufficiency and failure to undergo puberty because of hypogonadotropic hypogonadism. The DAX-1 protein is structurally related to orphan nuclear receptors, although it lacks the characteristic zinc finger DNA-binding domain that is highly conserved in other members of this family. In this report, we describe the clinical features and genetic alterations in six families with AHC. These patients reveal the variable clinical presentation of adrenal insufficiency in AHC and underscore the importance of considering this diagnosis. Nonsense mutations that introduce a stop codon were found in three cases (W171X, W171X, Y399X). Frameshift mutations (405delT, 501delA, and 702delC), each of which resulted in a premature stop codon at amino acid 263, were found in the other three families. Three of these mutations (Y399X, 405delT, 702delC) are novel. Using transient gene expression assays to assess DAX-1 function, these mutations were shown to eliminate the ability of DAX-1 to repress the transcription of genes that are stimulated by a related nuclear receptor, steroidogenic factor-1. These studies reveal the variable clinical presentation of DAX-1 mutations and emphasize the value of genetic testing in boys with primary adrenal insufficiency and suspected X-linked AHC.

Adrenal Insufficiency↗
PubMed1999

[Changes in TGF-beta 1 and type I, III procollagen gene expression in keloid and hypertrophic scar].

OBJECTIVE: The expression of mRNA for TGF-beta 1, type I, III procollagen in keloid and hypertrophic scar was investigated in order to elucidate the pathogenesis of and the difference between keloid and hypertrophic scar. METHOD: Dot-blot hybridization analysis was used to examine the type I, III procollagen and the expression levels of steady-state mRNA. In situ hybridization allowed direct assessment of the distribution of TGF-beta 1 mRNA in the tissue. RESULTS: 1. Our study indicated that the expression level of mRNA for TGF-beta 1 significantly increased in keloid and hypertrophic scar compared with normal scar and normal skin. 2. In keloid tissues, type I precollagen mRNA expression was selectively increased. However, in hypertrophic scar, type I and III collagen mRNAs expressions were simultaneously increased. CONCLUSION: TGF-beta 1 plays an important role in the pathogenesis of keloid and hypertrophic scarring. It implicates that distinct molecular mechanisms are operative in the development of keloid and hypertrophic scarring.

Cicatrix, Hypertrophic↗
PubMed1999

[Alteration of CD44v3 and CD44v6 expression in oral premalignant epithelia].

OBJECTIVE: To investigate the expression of CD44v3 and CD44v6 in oral premalignant epithelia and its relationship to the carcinogenesis of oral mucosa. METHODS: 85 normal, hyperplastic, dysplastic and malignant oral epithelia were studied by immunohistochemistry. RESULTS: Normal and hyperplastic epithelia showed strong CD44v3, v6 staining on cell membrane. Cells in the deep layers of moderate and severe dysplastic epithelia showed remarkably reduced staining intensity or no positive staining as compared with normal and hyperplastic epithelia. This down-regulation of CD44v3, v6 expression was noted in all 12 cases of severe dysplasia. In invasive front of squamous cell carcinoma and some metastases to lymphnode CD44v3 and v6 staining were also weak or negative. CONCLUSION: Low level expression of CD44v3 and v6 exists in moderate and severe epithelial dysplasia. This may be related to the reduction of cellular adhesion and thereby facilitates the infiltration of basement membrane by dysplastic cells.

Glycoproteins↗
PubMed1998

Highly efficient and consistent gene transfer into dendritic cells utilizing a combination of ultraviolet-irradiated adenovirus and poly(L-lysine) conjugates.

Dendritic cells (DCs) are capable of presenting tumor-associated antigens and subsequently play an essential role in T-cell activation. The aim of this study was to develop an efficient method for gene transfer into DCs. These genetically transduced DCs can then be used as potent inducers of specific cell-mediated immune response. When compared with physical methods for gene transfer (lipofection and calcium phosphate precipitation), adenovirus (AdV) vectors proved to be highly efficient for gene transfer into DCs. To overcome concomitant AdV gene expression and potential immunogenicity, AdVs were irradiated with UV. The UV dose was optimized to block AdV transcription without altering AdV receptor binding and endocytosis capacity. We subsequently used a polycationic amino acid compound, poly(L-lysine), to conjugate the irradiated AdVs to transgenes. The resulting complexes were found to mediate a highly efficient transfer of transgenes into DCs, without concomitant expression of AdV gene products. Low titers of irradiated AdVs were sufficient for a consistent gene transfer into DCs. This is the first study to demonstrate efficient, consistent, and practical gene transfer using an UV approach to irradiated AdV-poly(L-lysine) conjugates and should be useful for the development of DC-based tumor vaccine therapies.

Adenoviridae↗
PubMed1998

Electromyogram-triggered neuromuscular stimulation for improving the arm function of acute stroke survivors: a randomized pilot study.

OBJECTIVE: To assess the efficacy of electromyogram (EMG)-triggered neuromuscular stimulation (EMG-stim) in enhancing upper extremity motor and functional recovery of acute stroke survivors. DESIGN: A pilot randomized, single-blinded clinical trial. SETTING: Freestanding inpatient rehabilitation facility. PATIENTS: Nine subjects who were within 6 weeks of their first unifocal, nonhemorrhagic stroke were randomly assigned to either the EMG-stim (n = 4) or control (n = 5) group. All subjects had a detectable EMG signal (>5 microV) from the surface of the paretic extensor carpi radialis and voluntary wrist extension in synergy or in isolation with muscle grade of <3/5. INTERVENTION: All subjects received two 30-minute sessions per day of wrist strengthening exercises with EMG-stim (experimental) or without (control) for the duration of their rehabilitation stay. MAIN OUTCOME MEASURES: Upper extremity Fugl-Meyer motor assessment and the feeding, grooming, and upper body dressing items of the Functional Independence Measure (FIM) were assessed at study entry and at discharge. RESULTS: Subjects treated with EMG-stim exhibited significantly greater gains in Fugl-Meyer (27.0 vs 10.4; p = .05), and FIM (6.0 vs 3.4; p = .02) scores compared with controls. CONCLUSION: Data suggest that EMG-stim enhances the arm function of acute stroke survivors.

Activities of Daily Living↗
PubMed1998

Adenovirus-mediated interleukin-2 production by tumors induces growth of cytotoxic tumor-infiltrating lymphocytes against human renal cell carcinoma.

Combination therapy with interleukin-2 (IL-2) and tumor-infiltrating lymphocytes (TILs) demonstrates significant clinical activity in patients with metastatic renal cell carcinoma (RCC). To investigate whether local delivery of IL-2 via gene transfer is capable of improving the potency and efficacy of in vitro propagated TILs as compared with standard growth conditions [400 BRMP U (BU)/ml], a replication-deficient adenovirus expressing the human IL-2 gene under control of the cytomegalovirus (CMV) promoter (Ad-IL-2) has been constructed in our laboratory. RCC-TIL cultures were initiated by directly infecting RCC tumor suspension with Ad-IL-2 at a multiplicity of infection of 10:1. Subsequently the TIL cultures were restimulated with nonirradiated autologous RCC infected with Ad-IL-2 (RCC-Ad-IL-2) every 10 days (TIL/tumor = 50:1). Cell growth, phenotype, cytotoxicity, and cytokine messenger RNA (mRNA) expression were analyzed and compared with TIL growth stimulated with exogenous IL-2 (400 BU/ml). All five TILs tested responded to RCC-Ad-IL-2 activation, and a completed clearance of tumor cells was observed in cultures within 7-10 days. Lysis of nonirradiated RCC-Ad-IL-2 cells by TILs also was observed in cultures 3-5 days after restimulation. The IL-2 concentration in cell culture supernatants was maintained between 10 BU and 35 BU/ml (2 and 7 ng/ml), respectively. When compared with exogenous IL-2, RCC-Ad-IL-2 induced less growth expansion of TILs whereas a reduced CD56+ (23 +/- 14% vs. 44 +/- 13%; p < 0.05) but increased CD3+CD4+ cell population (32 +/- 11% vs. 15 +/- 6%; p < 0.05) with enhanced T cell-receptor use (59 +/- 10% vs. 42 +/- 7%; p < 0.005) was determined. An augmented human leukocyte antigen (HLA)-restricted and tumor-specific cytotoxicity was detected in RCC-Ad-IL-2-expanded TILs (day 35, 15.3 +/- 4.2 LU vs. 4.6 +/- 1.8 LU; p < 0.005). These properties were mediated by the CD8+ and CD4+ T-cell populations, as demonstrated by antibody-blocking assays. A unique cytokine profile also was detected in RCC-Ad-IL-2-induced TILs, which demonstrated an upregulation of both GM-CSF and IL-6 mRNA as compared with TILs expanded in the presence of exogenous IL-2. These data suggest that RCC-Ad-IL-2 is a potent immune stimulant that can be used in vitro as an immunogen to propagate cytotoxic RCC-TILs for adoptive immunotherapy or potentially in vivo by direct injection as a live tumor vaccine.

Adenoviridae↗
PubMed1998

Human health and chemical mixtures: an overview.

Unlike laboratory animals, people are rarely exposed to a single hazardous chemical. However, most of the information documenting adverse human health effects from environmental and occupational contaminants has come from studies focused on exposure to single chemicals, and there is little information available on how two or more contaminants affect humans. Most information on the effects of mixtures comes from animal systems and limited investigations of isolated human cells in culture, even though the study of mixtures in such systems has also been neglected. Two or more compounds may show additive, antagonistic, or synergistic interactions or may act on totally different systems and thus not interact. Furthermore, even a single chemical may have multiple effects and affect more than one organ system. Effects may vary with age, and metabolites may have totally different actions from the parent compound. This paper will review the variety of health effects in humans that may result from environmental contaminants and discuss how such contaminants may interact with each other. We will also present examples on how different contaminants interact from toxicologic studies of polychlorinated biphenyls performed as part of our Albany, New York, Superfund Basic Research Program project.

Animals↗
PubMed1998

Caring in context: caring practices in a sample of Hong Kong nurses.

In an effort to place the international literature and research in nursing in a Chinese cultural context a study was commenced to examine the caring practices of nurses in Hong Kong. In view of a recent study (Wilkes & Wallis, 1993) which utilised Roach's 5Cs of caring (Roach, 1987, 1992), a pilot study was commenced on a sample of 77 Hong Kong Registered Nurses studying a Diploma of Nursing. An open ended questionnaire was designed which asked nurses to respond to questions about caring in general and the 5Cs: compassion, competence, confidence, conscience and commitment. The questions asked what each of the concepts meant to them as a nurse. Data was analysed into themes based on key words for each of the six areas revealing that the sample of Hong Kong nurses viewed caring in a similar light to those in overseas studies. The sample highlighted compassion and competence as their major features and it is suggested that methodological problems may have inhibited a deeper analysis of their caring attributes and behaviours. When asked to expand on the 5 Cs in terms of their own practice they were able to supply themes which were closely related to Roach's definitions but which may have been more 'textbook' in their origin and certainly lacked a richness of response. The paucity of responses in terms of clarity and richness of data, followed by discussions with the participants led to conclusions about the methodological issues of cross-cultural research and recommendations for future research are made. Highlighted are the problems with attempting to use concepts such as the 5 Cs across cultures and the problems encountered with translation of concepts related to caring from Chinese into English, and vice-versa. The study has provided some insights into the concepts of caring in Hong Kong Chinese nurses. In the light of advances in China and unification of previously separate countries these findings provide and offer insights into nursing in China and are encouraging for future research.

Clinical Competence↗
PubMed1998

[Basaloid squamous cell carcinoma: clinical pathological and immunohistochemical study].

OBJECTIVE: To investigate the clinicopathological and immunohistochemical characteristics of basaloid squamous cell carcinoma of oral cavity. METHODS: Routine HE staining and immunohistochemical staining. RESULTS: Basaloid squamous cell carcinoma accounted for 1% of oral squamous cell carcinoma and was more common in male. It could be found at anysite of oral mucosa. The tumor was composed of basaloid cells and squamous cells. Basaloid cell, the main tumor cell, arranged in sheets and nests. Mitosis and comedoform necrosis was often seen. Adjacent oral epithelium often exhibited dysplasia. The tumor cells were cytokeratin positive, S-100 negative; PCNA index was high; 50% cases were p53 positive. CONCLUSION: Oral basaloid squamous cell carcinoma was a higher grade malignant tumor as compared with usual squamous cell carcinoma and should be paid great attention both in treatment and in pathological diagnosis.

Adult↗
PubMed1997

Identification of a positive regulatory element responsible for tissue-specific expression of prostate-specific antigen.

The prostate-specific antigen (PSA) promoter (PSA-P) has been identified, characterized, and determined to be tissue specific. Compared with high expression of the genomic PSA gene in prostate cells, expression of the transgene driven by the putative PSA promoter is low. This suggests that the identified promoter may be incomplete or may function optimally with additional regulatory elements. To identify the presence of additional regulatory elements, we screened sequences upstream of the PSA promoter and identified a DNA fragment of 822 bp, which enhances PSA gene expression. Combining the newly identified PSA gene regulatory sequence (PSAR) with our previously identified PSA promoter (PCPSA-P) exhibited enhanced expressional activity in the PSA-producing LNCaP cell line. With the addition of 10 to 100 nM dihydrotestosterone, a more than 1000-fold increase in expression was observed as compared to androgen-negative controls. Furthermore, although the combined regulatory element (PSAR)-PSA promoter (PCPSA-P) sequence resulted in high transgene expression in LNCaP cell lines, the combined regulatory element-promoter sequence resulted in minimal expression in the non-PSA-producing prostate cell line PC-3, renal tumor cell line R11, and cervical adenocarcinoma cell line HeLa. The newly identified 822 bp alone could also function as a promoter. Compared with the combined promoter, however, the 822-bp fragment alone demonstrated lower activity and lower responsiveness to androgen stimulation. Our results suggest that coupling the PSA promoter with an upstream regulatory element results in a marked increase in PSA expression, suggesting that the complete PSA promoter contains two functional domains: a proximal promoter and a distal promoter, which can also function as an enhancer. The enhanced gene expression of the new construct, combined with its tissue specificity and androgen responsiveness, in turn provides a foundation for the development of tissue-specific vectors for prostate cancer gene therapy.

Base Sequence↗
PubMed1997

Congenital adrenal hyperplasia.

Cogenital adrenal hyperplasia (CAH) is a family of genetic disorders from a deleterious mutation in a gene encoding adrenal steroidogenic enzyme essential for cortisol biosynthesis. Recent molecular advances have provided the genetic basis for the phenotypic variability in CAH, a means for accurately genotyping family members of CAH patients including prenatal prediction of the genotype in fetuses at risk of the disorder, and have helped to better define the hormonal criteria for the varying spectrum of CAH disorders. Biochemical advances have simultaneously aided the diagnosis and therapeutic monitoring of CAH patients. Prenatal maternal dexamethasone therapy for fetal CAH prevents or minimizes virilizing sequelae in the majority of prenatally treated affected females, but was associated with significant maternal side effects. Newborn screening for CAH has contributed to the prevention of morbidity of delayed diagnosis of CAH in more than two third of affected neonates. Current treatment methods, however, may not be optimal for achieving normal genetic height and appropriate weight in CAH patients, and more effective approaches to CAH therapy remain to be explored.

Adrenal Hyperplasia, Congenital↗