Green light for steroid hormones.
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3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
Biomedical subjects
D W Russell
Publications and source records attributed to D W Russell.
Foamy virus vectors.
Human foamy virus (HFV) is a retrovirus of the spumavirus family. We have constructed vectors based on HFV that encode neomycin phosphotransferase and alkaline phosphatase. These vectors are able to transduce a wide variety of vertebrate cells by integration of the vector genome. Unlike vectors based on murine leukemia virus, HFV vectors are not inactivated by human serum, and they transduce stationary-phase cultures more efficiently than murine leukemia virus vectors. These properties, as well as their large packaging capacity, make HFV vectors promising gene transfer vehicles.
3T3 Cells↗
UCLA Loneliness Scale (Version 3): reliability, validity, and factor structure.
In this article I evaluated the psychometric properties of the UCLA Loneliness Scale (Version 3). Using data from prior studies of college students, nurses, teachers, and the elderly, analyses of the reliability, validity, and factor structure of this new version of the UCLA Loneliness Scale were conducted. Results indicated that the measure was highly reliable, both in terms of internal consistency (coefficient alpha ranging from .89 to .94) and test-retest reliability over a 1-year period (r = .73). Convergent validity for the scale was indicated by significant correlations with other measures of loneliness. Construct validity was supported by significant relations with measures of the adequacy of the individual's interpersonal relationships, and by correlations between loneliness and measures of health and well-being. Confirmatory factor analyses indicated that a model incorporating a global bipolar loneliness factor along with two method factor reflecting direction of item wording provided a very good fit to the data across samples. Implications of these results for future measurement research on loneliness are discussed.
Adult↗
Immunohistochemical localization of steroid 5 alpha-reductase 2 in the human male fetal reproductive tract and adult prostate.
The activity of the type 2 isozyme of steroid 5 alpha-reductase is crucial for normal development of the external genitalia and prostate in human males. We used immunohistochemistry to localize type 2 isozyme expression in the human male fetal reproductive tract and adult prostate. In fetal tissue, the stroma of the seminal vesicles, corpus cavernosum, corpus spongiosum, dorsal vein complex, scrotal skin, and prostate expressed the enzyme. In addition, the epithelial cells of the fetal urethra and proximal prostatic ducts stained positively. The type 2 isozyme could not be detected in epithelial cells of the fetal prostatic acini, seminal vesicles, prostatic utricle, ejaculatory ducts, epididymides, and Cowper's glands. Adult prostate specimens were derived from transurethral prostatectomies performed for benign prostatic hyperplasia. Enzyme expression in these benign prostatic hyperplasia samples localized to the stroma and epithelial cells of the urethra and proximal ducts. No staining was detected in the acinar (luminal and basal) epithelial cells. Double staining with an antismooth muscle actin antibody localized type 2 isozyme expression to the stromal fibroblast cells of the prostate. Double staining with an androgen receptor antibody localized AR expression to the acinar epithelial cells and stromal fibroblasts. These data indicate that 5 alpha-reductase type 2 is expressed throughout the developing male genitourinary tract and functions as both an autocrine and a paracrine mediator of growth and differentiation.
3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
Increased expression of early growth response-1 messenger ribonucleic acid in prostatic adenocarcinoma.
PURPOSE: We isolated genes whose expression differs between normal and malignant prostate. MATERIALS AND METHODS: Differential display polymerase chain reactions revealed a messenger ribonucleic acid (mRNA) with higher expression in prostatic adenocarcinoma versus age matched normal tissue. Deoxyribonucleic acid sequencing identified this mRNA as the product of the early growth response-1 gene. RESULTS: Early growth response-1 mRNA levels were elevated in 12 of 12 intraprostatic adenocarcinomas but not in breast or ovarian cancers, or in rapidly dividing rat ventral prostate cells. Early growth response-1 mRNA was detected in epithelial and stromal cells at tumor margins but not in lymph node metastases. CONCLUSIONS: Early growth response-1, a nuclear transcription factor, is implicated in the growth and invasion of intraprostatic cancers.
Adenocarcinoma↗
DNA synthesis and topoisomerase inhibitors increase transduction by adeno-associated virus vectors.
Viral vectors based on adeno-associated virus (AAV) preferentially transduce cells in S phase of the cell cycle. We recently found that DNA-damaging agents increased the transduction of nondividing cells. However, the optimal concentrations were toxic to cells. Here we show that the transduction of normal human fibroblasts by AAV vectors is increased by prior exposure to DNA synthesis inhibitors, such as aphidicolin or hydroxyurea, and topoisomerase inhibitors, such as etoposide or camptothecin. Transduction efficiencies could be increased > 300-fold in stationary cultures at concentrations that did not affect cell viability or proliferative potential. Both S-phase and non-S-phase cells were affected, suggesting that cellular functions other than replicative DNA synthesis may be involved. Applying these methods to gene transfer protocols should improve prospects for gene therapy by AAV vectors.
Aphidicolin↗
The effects of human serum and cerebrospinal fluid on retroviral vectors and packaging cell lines.
Human serum is known to inactivate many retroviruses, including murine leukemia viruses (MLV). Exposure of vectors based on MLV to human serum components would presumably decrease the efficiency of gene transfer in vivo. Human serum also lyses xenogeneic cells, which would affect the survival of retroviral vector packaging cells in vivo. The effects of other body fluids, such as cerebrospinal fluid (CSF), on MLV vectors and packaging lines have not been studied. We have found that retroviral vectors packaged in ecotropic, amphotropic, and gibbon ape leukemia virus (GALV) envelope proteins were all inactivated by human sera, and human sera also lysed mouse NIH-3T3 cells and the retroviral vector packaging cells derived from them. Human fibroblasts producing amphotropic vector particles were resistant to lysis, but the particles produced by them were inactivated. In contrast, CSF did not inactivate MLV vectors, nor did it lyse murine retrovirus packaging cells. Our results suggest that exposure to human serum may prevent in vivo gene transfer by MLV vectors and xenogeneic packaging lines, but gene transfer within the central nervous system should be more successful.
3T3 Cells↗
Women with steroid 5 alpha-reductase 2 deficiency have normal concentrations of plasma 5 alpha-dihydroprogesterone during the luteal phase.
Steroid 5 alpha-reductase 2 deficiency has been identified in two adult women from unrelated families, one a homozygote and the other a compound heterozygote. The homozygote carries the G183S mutation and is the sister of an affected male; the compound heterozygote (R246W/splice junction abnormality) is married to a heterozygote (splice junction abnormality) and is the mother of two compound heterozygotes and two homozygotes. The fact that these two women are the mothers of seven children and appear to be endocrinologically normal confirms the previous deduction that this disorder is not manifest in women. Concentrations of plasma 5 alpha-dihydroprogesterone were normal in these two women during the luteal phase; this finding implies that circulating 5 alpha-dihydroprogesterone in women is derived principally from the steroid 5 alpha-reductase 1 isoenzyme and leaves unresolved the question of whether 5 alpha-dihydroprogesterone plays a physiological role in women.
3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
Expression and regulation of steroid 5 alpha-reductase in the urogenital tract of the fetal rat.
Two androgens, testosterone and dihydrotestosterone, are required for the development of the male urogenital tract in the rat. Testosterone is secreted by the fetal testes and is thought to elicit differentiation of the Wolffian ducts into seminal vesicles, vas deferens, and epididymides. Testosterone is converted into dihydrotestosterone by steroid 5 alpha-reductase in the urogenital tract, and this conversion is necessary for the differentiation of the prostate and external genitalia. Genes encoding two 5 alpha-reductase isozymes, designated type 1 and type 2, have been identified. We examined the expression and regulation of these genes on days 17-21 in the urogenital tracts of male and female fetuses. Expression of the type 1 gene predominated in epithelial cells, whereas type 2 gene expression was limited to mesenchymal cells. Surprisingly, this expression pattern was detected in both testosterone-dependent and dihydrotestosterone-dependent anlagen of the urogenital tract and was the same in both male and female fetuses. Furthermore, transcripts encoding the two isozymes were present in their respective cell types before the overt differentiation of internal genitalia. Androgens stimulated expression of the type 2 gene in the urogenital tracts of both sexes, but did not effect expression of the type 1 gene or the cell type-specific expression patterns of the 5 alpha-reductase genes. In the adult prostate, 5 alpha-reductase gene expression is under feedforward control, in which the product of the enzyme, dihydrotestosterone, stimulates the expression of the gene. However, no evidence for feedforward regulation of either 5 alpha-reductase gene was detected in the fetus.
3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
Four is not more than two.
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Cytochrome P-450 CYP11B2↗
Adeno-associated virus vectors preferentially transduce cells in S phase.
Vectors based on adeno-associated virus can stably transfer genes by chromosomal integration in recipient cells. In this study we have infected stationary and dividing primary human fibroblast cultures with adeno-associated virus vectors encoding alkaline phosphatase and neomycin phosphotransferase. We find that the transduction frequency of S phase cells is about 200 times that of non-S phase cells. However, neither S phase nor mitosis is essential for transduction. Single-stranded vector genomes survive in stationary cultures and can be recruited for transduction by stimulating these cultures to divide. Stable transductants contain randomly integrated vector sequences. These findings have important implications for the use of adeno-associated virus vectors in gene therapy.
Alkaline Phosphatase↗
Natural mutagenesis study of the human steroid 5 alpha-reductase 2 isozyme.
The enzyme steroid 5 alpha-reductase utilizes NADPH to reduce the double bonds of a variety of steroid substrates with generalized 3-oxo, delta 4,5 structures. One substrate for this membrane-bound enzyme is testosterone, whose reduction to dihydrotestosterone is required for the embryonic differentiation of the external male genitalia and prostate. There are two 5 alpha-reductase isozymes, designated types 1 and 2, which have different biochemical and pharmacological properties. Inherited deficiencies of 5 alpha-reductase type 2 result in a form of male pseudohermaphroditism in which the external genitalia fail to develop normally. Here, nine additional mutations in the 5 alpha-reductase 2 gene in subjects with 5 alpha-reductase deficiency are described. The biochemical consequences of these mutations, as well as 13 previously identified missense mutations, were characterized by recreating the mutations in an expressible cDNA and transfecting into mammalian cells. Twelve of the 22 mutations inactivated the enzyme. The remaining 10 mutations impaired enzyme function by affecting either substrate or cofactor binding. Almost all mutations decreased the half-life of the protein, and all but one of the impaired enzymes had an altered pH optimum. The mutations provide insight into functional domains in the protein as well as an unusual acidic pH optimum characteristic of the 5 alpha-reductase type 2 isozyme.
3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
The molecular genetics of steroid 5 alpha-reductases.
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3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
Expression and regulation of steroid 5 alpha-reductase 2 in prostate disease.
The androgen dihydrotestosterone is synthesized by the enzyme steroid 5 alpha-reductase, and it is required for growth and development of the prostate. We used immunohistochemistry to examine the expression of the type 2 isozyme of 5 alpha-reductase in benign prostatic hyperplasia and prostate cancer. The type 2 isozyme is highly expressed within stromal cells in both disease states. No type 2 isozyme is detectable in a lymph node metastasis. Immunoblotting studies show that androgen ablation therapies substantially decrease isozyme expression in the epididymis but have a lesser effect on expression in the prostate. Finasteride therapy (2 weeks to 3 years) did not abolish expression of the prostatic type 2 isozyme nor did this drug treatment induce expression of the type 1 isozyme.
3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
Cell type specific expression of steroid 5 alpha-reductase 2.
Isozymes of steroid 5 alpha-reductase (5 alpha-reductase) have crucial roles in androgen physiology by synthesizing the potent hormone dihydrotestosterone. The expression pattern of the 5 alpha-reductase type 2 isozyme was determined in genital and extragenital tissues by developing an immunohistochemical assay using formalin-fixed tissue and affinity purified polyclonal antibodies that specifically recognize this isozyme. Expression was detected in basal epithelial and stromal cells of the normal prostate but not in luminal epithelial cells. Stromal cells of the seminal vesicle also expressed the type 2 isozyme. In contrast, staining was detected in epithelial cells of the epididymis but not in the surrounding stroma. Myofibroblasts in foreskin samples of normal and hypospadiac individuals expressed antigen and were distributed in bands throughout the prepuce, suggesting a clonal origin. In most cells the type 2 isozyme exhibited a perinuclear subcellular distribution. However, in liver hepatocytes the protein was distributed throughout the intracellular membrane compartment.
3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
Perceived parental social support and academic achievement: an attachment theory perspective.
The study tested the extent to which parental social support predicted college grade point average among undergraduate students. A sample of 418 undergraduates completed the Social Provisions Scale--Parent Form (C.E. Cutrona, 1989) and measures of family conflict and achievement orientation. American College Testing Assessment Program college entrance exam scores (ACT; American College Testing Program, 1986) and grade point average were obtained from the university registrar. Parental social support, especially reassurance of worth, predicted college grade point average when controlling for academic aptitude (ACT scores), family achievement orientation, and family conflict. Support from parents, but not from friends or romantic partners, significantly predicted grade point average. Results are interpreted in the context of adult attachment theory.
Adolescent↗
Male pseudohermaphroditism caused by mutations of testicular 17 beta-hydroxysteroid dehydrogenase 3.
Defects in the conversion of androstenedione to testosterone in the fetal testes by the enzyme 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) give rise to genetic males with female external genitalia. We have used expression cloning to isolate cDNAs encoding a microsomal 17 beta-HSD type 3 isozyme that shares 23% sequence identity with other 17 beta-HSD enzymes, uses NADPh as a cofactor, and is expressed predominantly in the testes. The 17 beta HSD3 gene on chromosome 9q22 contains 11 exons. Four substitution and two splice junction mutations were identified in the 17 beta HSD3 genes of five unrelated male pseudohermaphrodites. The substitution mutations severely compromised the activity of the 17 beta-HSD type 3 isozyme.
17-Hydroxysteroid Dehydrogenases↗
DNA-damaging agents greatly increase the transduction of nondividing cells by adeno-associated virus vectors.
None of the vector systems currently available for gene therapy applications have been shown to be capable of both efficient gene transfer into nondividing cells and long-term expression through stable integration into host cell DNA. While integrating vectors based on adeno-associated virus are capable of mediating gene transfer into nondividing cells, this process is 200-fold less efficient than transduction of dividing cells. We demonstrate that the transduction efficiency of adeno-associated virus vectors can be increased by treatment with DNA-damaging agents. Nondividing cells are especially responsive, with increases in transduction efficiency of up to 750-fold. This finding has the potential to facilitate gene therapy applications requiring gene transfer to nondividing cells.
Alkaline Phosphatase↗